Spray Application Methods For Furniture Finishing

Transcript

Spray Application Methods for Furniture Finishing November lo, 1994 Greensboro-High Point Marrion Greensboro, North Carolina Sponsored by the Society of Manufacturing Engineers in cooperation with the Association for Finishing D -------- -I riir I I __ - SPRAY APPLICATIONS FOR FURNITURE FINISHING BY JERRY P. H U N D m SPRAY APPLICATIONS FOR FURNITURE FINISHING TABLE OF CONTENTS SUBJECT .................................................... .................................... Dirt Is A Four Letter Word to Furniture Finishers .............. Viscosity ....................................................... Compressed A i r Spray Gun Principles ........................... A i r Nozzle Selection ............................................ High Volume Low Pressure - HVLP ............................. Fine Tuning Your HVLP System ................................ Hose and Fittings .............................................. Compressed A i r Supply ........................................ Material Supply ................................................ Plural Component Spray Systems ............................... Airless Spraying ............................................... A i r Assisted Airless ............................................ High Transfer Efficiency Spray Application Systems ............ Hot Spraying ................................................... Automatic Spray Equipment ..................................... Safety Considerations in Paint Application ...................... Introduction Spray Application Processes Paint Curing By Infrared Catalytic Thermoreactors ............. .................................................. Operator Techniques ............................................ How To Maintain A Spray Gun .................................. Guide To Finishing Technology ................................. Notes .............................................. ;............ Spray Booths PAGE . 1 11 16 18 20 33 36 43 45 53 71 90 100 111 115 117 121 126 131 135 155 161 164 168 SPRAY APPLICATIONS FOR FURNITURE FINISHING Jerry P. Hund INTRODUCTION Since the days of the cave man, man has applied materials of one type or another to protect and/or decorate his possessions. Furniture has always been one of man's most prized possessions. Although many materials have been used, wood has remained the most popular material for furniture. Many people down through history have worked with wood in one form or another the most famous of which being the one referred to as "The Carpenter's Son". One thing that has always posed itself as the most difficult challenge is how do we finish our furniture in order to give it that protection and decoration that will make it out-sell the competion. @, Q! kLl&G - . - J=Y a4-Q-p-+-F Man has developed many coatings and methods of applying these coatings to furniture down through history, many of which remain in use today, and rightly so. With the dawn of the Industrial Revolution, newer coatings and processes emerged. Compressed air atomization became popular in the early part of the twentieth century. This process allowed furniture finishers to speed up production in order to keep up with demand. In the middle part of this century, newer finishing processes emerged to compete with compressed air. Airless and electrostatic spraying proved worthwhile to many furniture manufacturers and other manufacturers as well. What's new in spray equipment for furniture finishing? Really, the last major breakthrough was the invention of the spray gun to replace the brush. In .the decades since that time changes have been in the form of continuous improvements and refinements in the equipment to obtain better atomization of the coatings, better finishes, improved production and lower cost. new and improved coating materials have entered the market, spray application equipment has been adapted to spray them. As production became mechanized, finishing equipment met the challenge with automatic equipment. When regulations called for reduced emission of volatile organic compounds (VOC), manufacturers of spray equipment found new ways to improve the transfer efficiency of spray equipment and to clean exhaust air. As Today, this evolution in spray equipment continues unabated as new coating materials and manufacturing methods come into use. Although the basic principle of operation remains unchanged, spray equipment has become highly refined and diversified. New manual and automatic spray gun designs and nozzle combinations meet the requirements for optimum coverage of an almost endless range of paints, lacquers, stains, twocomponent materials , adhesives, and other materials. The application of coatings by computer operated vertical and horizontal reciprocators, spindle and rotary machines, and similar automatic devices remains a major method of increasing production and controlling the quality of the finish. These systems can be varied to meet many requirements. Overspray and paint consumption are minimized by electronic sensors to control the triggering of the guns in conformance with the shape, size and movement of the product being finished. ! Electrically driven robots are probably the latest addition to the wide array of finishing equipment on the market today. Their adaption to spray finishing operations solves many problems beyond the capability of standard automatic equipment. Because a robot can reach into and around a product, it is ideal for painting irregular shapes and the interior of enclosed areas. Prior to the use of robots, these operations required manual finishing, frequently with considerable operator discomfort or hazard. Robots offer economies where the conveyor in the finishing department carries a variety of products, each requiring its own spray pattern. Thanks to today's advanced electronic equipment, a robot can sense the product in front of it and select the right program from its memory to finish the product uniformly. A robot is also an ideal substitute where the health and safety of workers is in question. However, most furniture lines still require the skill of trained sprayers to "read the surface" of the wood before manually spraying the furniture. Recent development in finishing equipment include a process which combines two finishing processes into one. Air Assisted Airless, when used under ideal conditions, employs the best features of compressed air and airless spraying. This method uses a specially designed gun and pump. The fluid is delivered to the spray gun at low airless pressures (150-800 psi) where it is partially atomized by an airless tip. Atomization is completed by introducing low amounts of atomizing air (5-30 psi) into the airless pattern. The result is a finely atomized pattern that closely resembles that of compressed air. This process also reduces fog and overspray, allows spraying into cavities, provides a higher film build per pass, while consuming up to 5 0 % less air that an ordinary compressed air finishing system. All this adds up to improved transfer efficiency and costs savings. We can also include the process of electrostatic air assisted airless for even greater transfer efficiencies. Although most wood furniture finishers would select air assisted airless, many metal finishers may want to consider the electrostatic options available to them. Recently, the need for furniture finishers in many areas of the country to comply with stricter emissions regulations has forced them to change to more efficient spray systems. Several new processes have recently emerged that offer great Potential for furniture finishers. F I i The first process is commonly referred to as high volume low pressure (HVLP) atomization. HVLP atomization works similarly to conventional air spraying with several notable exceptions. First, jets of high pressure low volume air exiting the nozzle are now replaced by soft columns of high volume low pressure air. Secondly, larger interior diameter air hoses feed specially constructed spray guns which may restrict the atomizing air pressure within the spray gun, or have its pressure restricted prior to its entry. Finally, air used to atomize the coating can originate from high speed turbine operated blowers or from existing air compressors. Regardless of the manufacturer, all HVLP systems use between 15-30 cfm (volume) and 1-10 psi (air pressure) to atomize a soft highly efficient air spray. Although exceptions exist, many turbine operated HVLP systems have found a home in smaller wood finishing operations due in part to their portability. Air conversion HVLP systems have made a dominant showing in larger furniture plants mainly because of their ability to use existing shop air. Newly released HVLP air assisted airless spray guns allow high speed furniture lines to keep up with production while still achieving the benefits of HVLP. The second process is known as low pressure low volume (LPLV) air atomization. It can also be considered a low pressure air assisted airless system. LPLV atomizes material with jets of low pressure low volume compressed air strategically impinged into a flattened cross sectional fluid stream exiting the spray gun. Fluid pressures range from 20-70 psi, air pressures from 5-15 psi and air volume consumption between 3-8 cfm. When compared to air assisted airless and compressed air atomization the figures illustrated here demonstrate that it truly is a low pressure low volume atomization process. As with turbine operated HVLP sprayers, LPLV systems are also very portable. LPLV is ideal for spraying low viscosity coatings such as Stains, sealers and some top coats on a low production finishing line or custom finishing operation. Both methods described here offer unique advantages such as high transfer efficiency ( 6 5 - 7 5 % ) , sprays well into recesses without excessive bounce back, reduced material costs, lower emissions, reduced booth maintenance and hazardous waste and are easy to operate. As improvements are made in both systems, look for improved atomization quality. In some cases, these newer systems may not match the ultimate finish quality of compressed air atomization. However, most furniture finishers are finding both systems to adequately meet their needs and the EPA's. new process, developed by Union Carbide, called the UnicarbR process substitutes carbon dioxide for a substantial quantity of the fast evaporating solvent (up to two thirds) normally used in the spray application of certain coatings. A The UnicarbR process uses carbon dioxide that has reached a super critical state. When C02 is heated to a critical temperature of @ 00'F and a super critical pressure of @ 1070 psi the gas turns into a dense fluid which is used as a substitute for a large portion of the solvent. Delivery equipment is used to accurately meter and mix the C02 with.the coating concentrate. Finally the mixture is sprayed under airless conditions either manually or automatically. The furniture industry is targeted as a major end user for this process for obvious reasons. As improvements are made and costs reduced, the UnicarbR process will become a major player in this industry as well as other industries. Electrostatic application of coatings has ushered in new economies in the finishing of furniture. This method has long been an advantage in finishing metal desks, filing cabinets, and other metal furniture, but recent developments make it practical for use with wood furniture when the surface is properly prepared. The high transfer efficiency of electrostatic spray finishing not only saves material but is a major help in reducing VOC levels (due to the reduction of the coatings used) in the exhaust from spray booths. i 4 4 I I with other spray equipment, electrostatic applicators are constantly undergoing improvements. Smaller, safer, more maneuverable hand guns are now in use. Some even use air operated turbines mounted directly on the spray gun which provide the necessary voltage. This eliminates the power supply and cable to the gun. As Electrostatic HVLP is now available for those operations that require high transfer efficiency along with electrostatic "wrap". The development of compact high speed, electrostatic rotary bells and discs are adding a new dimension to this method of applying coatings. Some of the first electrostatic rotary' disc installations involved the coating of spindles, gun stocks and other long cylindrically shaped wood components. Transfer efficiencies as high as 95% are possible with these units. This equipment also makes it possible to effectively atomize the new high solids and water borne coatings which are becoming popular in furniture finishing. The rapid growth in the use of two-component materials such as polyesters (i.e. Wet Look), epoxies, polyurethanes, etc. has given rise to new equipment for precise metering, mixing and dispensing of the two components. Such equipment ranges from fairly simple but accurate metering pumps delivering a given ratio, to highly sophisticated computerized systems that permit selection of a wide range of component ratios which accurately monitor and report each step of the finishing operation. new generation of color changers now make it easier, faster and more economical to shift from one color or material to another in operations where products are finished in a range of colors or coatings. The change is quick, and eliminates the time-consuming job of purging one material before another can be sprayed. A Circulating systems, serving'from two to many spray stations, deliver coatings to all spray guns in the plant at the same uniform viscosity and color, assuring that parts finished in different work areas match in the final assembly. Such a system offers greater safety by eliminating the handling and clutter of individual material containers located at the spray stations. The development of improved paint pumps make circulating systems more efficient. Pumps, used to supply coating to spray equipment and to move it through circulation systems, have also been subject to evolution. New designs and materials contribute to extended service life and greater efficiency. Abrasive and corrosive fluids can be pumped for longer periods without pump maintenance. Air motors used on such pumps are now much quieter, operating at noise levels under those required by OSHA. Hydraulic power supplies have replaced air motors at many locations with little or no maintenance. Diaphragm pumps cah handle most coatings with less down time and is simple to repair. There will continue to be many and constant changes and mergers in existing equipment and methods as new materials and technologies come from the research and development Many of the revolutionary laboratories of the world. developments in electronics and computerization will be adapted to product finishing to improve automation, finish quality, and lower cost. Spray booths have undergone some major changes of late. For many companies the spray booth may still be the dirtiest place in the shop. For some spray operators, the feeling is the sooner they could transfer out of this area the better. Often it is unclean, noisy, poorly ventilated and illuminated. Coupled with this is the problem of what to do with the hazardous waste at clean up time. Those purchasing water wash spray booths soon realized they also purchased a problem with waste disposal. Those converting to or purchasing dry filter spray booths were not exempt from these problems either. OSHA inspectors continue to find more violations in the spray booth and adjoining areas than anywhere else on their inspections. Finally, dirty finishes are usually attributable to poor housekeeping in the spray booth. Spray booth suppliers understand these concerns and are busy developing alternatives. Newly improved centrifuge cleaning systems can now turn 12 drums of hazardous liquid waste into 1 or 2 drums of dry waste which in some cases can be considered landfill. Quiter fans help keep noise levels within OSHA levels. Easy to spray water based strippable white and clear booth coatings help keep walls and windows clean. Improved holding capacity of dry filter media can now reduce filter Cost. Long lasting galvanized or stainless steel booth panels have replaced the rust prone black iron panels of several years ago. Carbon adsorbtion and incenerators may become more popular as costs are reduced. When spray booth manufacturers find a way to easily remove solvent emissions from coating materials before being discharged into the atmosphere, EPA guidelines could become almost extinct. As we approach the 21st Century, the furniture industry will see a major emphasis placed on cutting emissions, (through the reduction or elimination of solvent based coatings) improving quality while cutting costs, and improving the transfer efficiency of its finishing operations. Improving transfer efficiency will not only cut material and disposal costs, but also allow furniture plants in many states to remain open for business. Recently enacted EPA regulations in some states now require methods of application to provide a 6 5 % transfer efficiency. Thus many furniture plants will want to reexamine their finishing operations to see if they can switch to more efficient and less polluting methods of atomization. I Regardless of the hype associated with today's spray application systems, all have their advantages and limitations. What may be suitable in one plant or operation may not be suitable in another. Equally important is the idea that regardless of the process selected, and the equipment supplier, all require maintenance. There is not maintenance free spray equipment in existence for sale today. I I II The purpose of this manual is to introduce you to the most current and popular forms of spray finishing and its related equipment used in the furniture field today, to show each one's advantages and limitations, and to reinforce . the 1ettureJdiscussions of the workshop. Although limited discussion on coating materials is made, this manual will deal primarily with the proper selection, operation, and maintenance of the spray finishing equipment. I .- 1, . Although many illustrations furniture related trades, my regardless of the product, or that material onto the product efficient and references are of nonpurpose is to show you that ware, our objective is to put in the most successful and cost The spray equipment and materials you're be found in other trades. using today may also Armed with this knowledge and a little common sense, you should be able to examine your own furniture finishing operations and see what improvements can be made to save you money, improve quality and allow you to meet EPA emissions requirements. I hope you will try out some of the ideas suggested in this manual. Many thanks go out to those assisting me and contributing to the contents of this manual. Spray Application Processes Rd. No. 1. 1.1 hOGe8B Umltrtloni -8WS Air Atomizatii-Most m m o o l y used for industrial finishing. Ccmplete pattem control. Finest atmizalim. Uses m m air. Creates most fog. Low transfer effiiancy. Siphon Fed-Uses Lcwest cost. Operata canies w g h t of material a gun. Sprays lght materials only. One qi. max. Spray position limited, vacuum created at mzzle to draw material from cup. External atomizati. Less maintenam. Change colon q u w . 12 Pressure Fed (extemal atomizalloo)-Uses external pressure source. tank or pump, to force material f r m nozzle. Material and air mix outside of nozzle. Delivers m m material than 1.1. Wider viscoriiy range. Sprays mosi materials. No air nozzle Mer. Spray in any posiiim. Mependent control over air and fluid pressures. C w u m e s most air. Creales moa log. 1.3 Pressure Fed (internal atomization)-Material and air mix inside Less fog than 12. Larger pattems. Less air msumpiion. Coarse a t m i z a t i . Fixed pattems. Nozzles war. Fast drying coatings noule. not reCo"ende4. 1.4 Pressure Fed (external atomization) with heated material-Same as 1.2 except material is heated to reduce viscosity. Better control. Fledumd air and fluid pressures. Limits overspray and rebound. Finer stomizatm for a better finish. Better adhesion. More film build per coat. Reduced Mushing. Reducedsoknt use. Not all materials can be heated. Special paint f m u l a t m s are required. A d d t i equipment to maintain. Equipment must be explosion proof (el%arical). Hgh electrical demand. Reduces pot lib for catalyzed coatings. 1.5 Low Fmssure Low Volume Atomization-Material is atomized by LPLV jets of air optimumly positioned to impinge onto Me fluid stream of elleptical cross section (inslead of the cowentiara1 round me)exiting the spray gun. Hgh lrdnsfer efficiency(65% to 75%). Sprays well into recesses and cavities. Very portable -em. Atomizatin not as fine as that of air spray. Not recommendedfa heavy materials Q where hqh pfoduciicm is Rquired. 1.6 Hgh Volume Low Ressure Atomizatm-Similar to that described in 1.2 except higher d u m e and l m r pressure (HVLP). Same advantages as described in Same disadvantages as described in 1.5 plus m e systems fa generating HVLP air may be 1.5 plus cDmpties with most air quality regulations. expensive. 2. Airless (hydraulic) AlomizatimAtomization caused by release of hgh fluid pressure through small oriflce. Most widely used by painting UXltraCtors & maintenance painters. Hgh fluid capability. Large patterns. Fastest spray applicatm process. Low air m s u m p i h . Limited fog and "bounce back -permits spraying into cavities. Potentially hazardous hydraulic injection. Hgher rate of werspray Sharp patterns: dHKuit to blend. Expensive nozzles (tips). Coarse atomizatm may flood surface. Equipment requires top maintenance. 2.1 Airless A l m i z a t i (heated)same as 2 except with heat to reduce viscosity. Used by furniture manufacturers and industrial finishers. Better Row of material. Hgher solids per pass of gun. Viscosity control. Finer atomization than 2. Strki maintenance. Same limitations as 2. 2.2 Air-AssistedAirless-lower fluid pressures than airless (normally below 1OM) PSI). Low pressure air IS added via the air nozzle to furlher atomize the already pre-atomized spray Used by furniture and industrial finishers. Material savings 50% better than air spray plus lower overspray and fog. Less tip wear: longer pump life ihan airless. Hgher film build per pass than air spray. Atomization not as fine as Air Spray. Hydraulic injecton may occur. Tip plugging. Stra maintenance. I h..r Rd. NO. Adnnla9.r Umitatlonr 2.3 Air Assisted Airless (Heated). Uses same principle as 2.2 with the a d d i l i of heat to reduw viscosity and improve flow. Better flow of material. Higher solids per pass of gun. Viscosity mlrol. Finer atanizatm than 2.2. Stnct matntenarce. Same iimitatlons as 2.2. 3. Electrostatic Atmiraton-VoHage differem between paint dispenser flow s~eedrotatino disc or bell) and *ran causes paint-to be attract& to the grounded work. Used by most appiiance manufacturers. Hgh production of uniformly shaped pa*. Hgh transfer efficiency @ 65-95%. "Wrap" around effect. waling other surfaces. Minimum overspray. Parts must be conductlw. 3.1 Electrostatic Attractim-Material is atomized using t W B n t i i a l air. airless. or air-assisted airless principles. Particles are electrically charged and attracted to the work. Electeity may be turned olf to permit normal spraying. "Wrap" around effect. Material savings through minimized overspray. Use with or without e l e c t d l Charge. Scme COnductive materials will require special equipment, Parts must be cwductiw. Difficultto penetrate cavities or recesses with power supply on. 3.2 Electrostatic Attraction (Using Heated Materials)-Same as 3.1 except materials are heated. Ahiliy to usa systems coupled together to get all the advantages as in 1.4.2.1.2.3 and 3.1. Same limitatis as in 1.4. 2.1 and 3.1. 3.3 Hgh Speed Rotataral AtanizersHQhspeed (10K-70K RPM) rotating disc a bell gives exiting paint particles veloctty and directiar. Voltage differential then takes m r and allows etectriiy charged paint particles to attract themselves to a grwnded part. High transfer efficiency. "Wrap" around effect. waling other surfaces. Works wll with hgh solids coatings. Minimum overspray Par& must be conductive. Limit to shapes that may be coated. Hgh productm rate required. HQh voltage and spinning cup or disc may be hazardous. Limit to shapes that may be coated. Hiah oroductlcn rate reouired. . ~. HGh &Itage andspinning cup or disc may be hazardous. I TYPICAL SPRAY SYSTEMS 1. URATOMUATION 13 PRESSUREFEEDTANK HOOKUP (Extanml atomizatlon) 011L Wstar 1.1 SIPHON FEED HOOKUP (External atomization) 1.3 PRESSURE FEED TANK HOOKUP (Intenul atomization) Slphm Cup 1.4 PRESSURE FEED HEATED MATERIAL (ExtomI atomization) 2.1 AIRLESS ATOMluTlON (Hutod) Air Suaa1v I .. u u 8.sk Pmssum Valva 1.5 LOW PRESSURE LOW VOLUME ATOMIZATION (LPLV) 1.6 HIGH VOLUME LOW PRESSURE ATOMIZATION (HVLP) 22 AIR ASSISTED AIRLESS ATOMlZATlON 2.3 Fluid 2. Fnssurc lank AIRLESS (Hydraulic atomization) AIR ASSISTED AIRLESS (Heated) . I Paint Film Defects ~ APPEARANCE CHALKING Lou of p1-r Pwdcry coaling on Ihe vlriace of I& pain1 tilm CHECKING. CRAZING. CRACKING crovioa reprratm Ichccki Irregular line spanlion ~slll$alorchccli Furmnuun l A c dried mud icrxkmpl CAUSE REMEDY &mow pourdcry tilm with A mild Wuthertng u l paint tilms lndficicnt panni apilailan U s of p r l y balanced thrnning pule rbnrive Sand and rcfinah a chronic fallme dW"l< CDndltWll In.witic~en1 drying of films prlor IO mcoriing Ealnme lemperriurc chanpn C u m roo huvy lcheckingi lnpredicnlr n u thoroughly mixed Adding i m p p c r mucrtals t inrmpalibiliiy 1 Rccoaimg checked linish Thinner rolicning acrylk i n u r n p i I L m m finirhdwn IhNvgh Ihc checked pain! film and rchnirh U x )oIvcm recommcndcdby Ihc punt rmnufaaurer Rut. oil or g m under suriace Moirlvrc in spny line T n p p d rolvenis Eapzmun of film 10 conrlinl or rrperted high humidity Sad and ntinirh dimrgrd area) lmpmper w i v e clunrng lmpmpr undercoats S'nd and rctinirh dnmrpcd a r m wbcc Unbalancedthinning wIyent> FISHEYES. CRATERING lmproperduning of old wrlvc Spraying m r finirhn that conuin silicm. oil. m o r w e r Wash off p r m while wll WCI Rub WI hnirh with P prlishtng mnpwrnd Snd and Kfinirh Rcmmc lilted surlaco and rcnnirh h r l thinnm an high humsdu? Unbdancedthinncn Cundcnwlmn on d d surface 3VCrKdUClwn E a t n 4~ thinning \dveni* X I burface being painted lmvmxrlr cleaned surfxc Add rcllrdcr IO lhinncr and mprr! %nd d ntinlrh PREVENTION A p u l e p i n 1 thomughl! UX d y Kcamended thmning solvents OT a d d i l m Thoroughly clean and irwi rubsirale Dram water Imm air itnn often Thinpmdunspropcrl) A l l w wlfincni drvine iime beiwccn INCREASING PRODUCTIVITY DIRT IS A FOUR-LETTER WORD TO FURNITURE Isolating the sources of contaminationis the h t step m getting dirt under control in fKIing operations. FINISHERS F o r ~ d o a n u l Gf i U s h c u l t h e p v l ' S hnd pasawways mm r o l ~ n tFu m e mum@ ckannp. remove rorrltr and w needles and soak the a n e m areas wipe dorm the exterm 01 the gm mm soivent. bnah and mpe SV " D e r . do not SDak me entire spray gun n wlvdnt. pst &an the affected areas Plpmo used m air Iims mll ususliy MI of moa as a reWn 01 mOatue laden air entermg the canpenor ll the compesxx uses 04 as a lubncant. chances are as d wears cul. ah. along wm cwdematlon. mll Unmteiy attunulate m the an supply hcs F h t m d e w k K m as 011 and water extractors. must be use3 to renwve lhese n n p n l ~ lrom ~ s the air betore at"mg the coawg These filters mll remove wbd partculate matter down to 5 m m orless WenwasthelasltmSomeone drained the mislue of totally cleaned oul snd replaced the disposable Mer n the extractcfs7 An examtion 01 meSe hlters mlt tell yw a lot abeut the condmcn ot the an svstem n use Don't l ~ g e to t r6p1?~t the low secbon of the an regulatms (of &'I as well Never lutxicate a regu!atot or extractu p s t clean them - ma worklng arm. h dirty More often than not. the q x a y area 01 a f W e Plant IS a n m but a clean and dni-free mnnronment Good haackeepnp K a must n order to rcduce ds,wntam~bon Raove &I and pant acummton from wak. (bcrs &ags. m-d Qll laMer regularly Pn~W~cally wet down nWrr and walls n and a r m the w a y area to captule and hold dust The tpray boom W i d be properly wscand e q ~ l p ped mm an aulunatc damper to p e m t back dralts Do rxlt saw M sand n u rear me w a y area k a w r g c d n " t K usmp &an. mliaammable papn on me l b ? s n and arand the spray area M t forgel to keep un~Umo(uedpnsornel aR 01 me spray area and spray boom They may be ds, caners 1mprop.r omration of ma rpray booth The o w r a l m of a spray boom IS a mpk ConCePt its purpose K to exhaust I w s and overspray away I r a n the spray opera tor and hnished pan However as me air IS reptaced there IS a teMency to draw dtrt mto the lx" from wrrDvnding areas n a w a y boom telles cn unhllered rnop ar as its an s w c e . men din m the hrush may never be mder COntIOl One soidon 15 to emlose the boothard use s ~ e u a Intake l hlters to remove the dirt belore it enters the spray area These hIters must be kept clean and should be me ~ecanmended type Ch some booms mese Inlake hltefs are cn the main 03M5 mlcn o w to allow the pans to be k q h t n a m wi ~ , ~ ~ m u s Mula tplw I W U s system to keep dul cul Q a d r m C ~ o f h c x l u a k ~ m f s b y w y n g a s c n p p n . and h l e It S SWI Wet. PrSU d drsCtly *I the make-up u Ibw Then. " c t d for dirt Otten nbratlom n the bruldinp or from bocm Ccus mll allow sure din to escape hm hcre Men and mto the fmsh When m dcubt. rwlace thasc Anen The deal h~lulm n any spray m m K to have an mdepadsnt lwced an make up system tor your encloKd boom The air eemanded by tkd booth comes lrom a =parate aw replacement vw( w i x h pcr ndes the unect m t 01 heated M c&Sd au wtuchKatJofWed By S u p p l y q a m 10 percent m e air nto the booth man SI beinp exhawsted. a poslhve p a a u e mll ds~elophat and dirt mll not enter wn rrmce doors are opened of hrwph seam and cracks 01 Me structure hstead they mll be forced away M a ~ p e m m tmay want 10 contldn svvltchmg to an e k t m a t c hnlshtnp system when pracbcal Donp so allows a 40 percent reducten of the amount 01 exhast at! requned by the 0ccupalional Salety and HealthAdmrustram Not my mll thls draw ~ n as t and 6n mrwphtwi me spayarea b u l a ~ a i w s a v e o n m e avm'r and coolinp bilk and c m W emw01-6 and r e d m costing co51s Don't OW the "riame 01 the exhast fiiim H IS an OSHA rcpulatun mat an 6,finer spray booms have a ww.1 p i g e or maTyyM)ter. ndicatiq when It e WU to change the exham Mters Tho draft gauw measures air resistance tha@meFdle!sWnoperatm Not cnly K 0 &gal to untrme to operate a boom mm the filters LXVW their capacity bul it a h u n ~ t e s t dul o m me fmnh haw poor oporator tochnlqua The operator WM sprays mm expcuues 01 excetsrvs Ian patters wiU untrlbute lar!piy to &st and overspray n the boom M IQ proper apraytrq tech rnques WII put m e of the coahng cm me pDdut and less on the walk lkcf.bases. extractors. etc Eventually mo dned mateMI wdl Wodpe from tnese U a c e s and m u p a s dKI n me hnrsh A 9pod rule to follow when Setting pessues K to always use the lowest DfeSSWeS mat will r wn n a satslactcq spay pattern The operator can improve Ius tech N Q U ~by controllng these five vanabk mainminng me pcper dsIance be weenme gun and the work. l Mhouph t e it M ~y te unwssible to control lhese a r u m s a11 the mn. try to teach gcca habits to w a y pctmneim wotr to reduce reject.% AnomCr pood &a IS to nan sMayiq areas of the praduct farlhest lrom the exhaust Ian. TI% w m i ~ the overspray and onspray to move wim the air I!Oover W mnmtshea Maces mto the exhaust. Dlrt and lint on tho clothing IS often overbked. M ckny overalls mm dust and Imt m cuffs. pockets. etc.. may destroy a perlect I ". Disposableor wash and wear overalb made 01 an anastatic matenal may be necessary to control din n the finsh. Many operattons are r o w prowdinp sprayers mth paper crommg. strue .Iectflclly electrluty IS often hard to accept as a culpit in the hishmp rcinn. Static elecWily. erpeclally when me humidity is low. will amact h o t parlicks like a macnet. Stabc newvaluers of eliminators may be requited. especial$ when s p a y q plastic pam. Tha best way to conuol statlc elecmny is to neuualue M g~oundau e k t r r calk conductive objects m the spray booth. T ~ I Sincludes the pan. the spray boom. the unveyu. the w m hoiders. and don't fofcet. the sprayer. The sprayer is gcweed by h o m g the w a y gm h the owfatot's bare hand. A " way ISto use cOMUttlve air a m Ikud W s m the system. h ' t l o r p i 10 Drounj thc matenal w p l y pump wim a pornd mre: Funlture mohen may fnd it IS almost impcasMc to cnmpktely eliminate din in the frrsh. kR by lollowinp some 01 me atow recommendatm. my S W d . at bast. be aMe to get it under control n waddbe very ww to ask the help 01 yar matenal wpller as well as your e q U l W t WrpplnW VI order 10 fight contarrmatun of your fintsnea Drffluct Don't omlook the pwrbiltty 01 payins an IC&. hshnp c m t t a n t to examine me Wnl's fauship operaton. Not only will he be aMe to troubleshocl the din problem. bul he can show you how to improve me overall applicatm enrlency as well. ovefIapping each pecediq stroke by 50 Percent. 0 keeplnp the pun perpendrcular 10 the w&. mamtaimng thc wnett gun movement. and trmring the gun betote and after each pa= 17 FINISHING ! VIScosm The paint user will find the EFFLUX Method (14) the most ;enerally employed. Bah Zlhn ud Ford cups are available with different size orifices to p i d e a wide nngc'of viscosity measurements. However. the two most widely used for print are he zrhn #2 and Ihc Ford #4. EOUIPMENT Viscosity cup. stopwatch. ucaroria as illusmted. PROCEDURE I . Rcplrr merial to be tested. Mix. suain, ctc. 2. Insure that cup is dean and orifice is free of residual dried Briefly, thc viscosity of a mutrial is an indicaticm of its ability to rrri,r flow.The now characteristics of liquids relate directly to the degree of internal friction, therefore, uything that will influence the internal friction (such as solventsthinners-or temperature change) will influence flow.SimiLily. it is the flow characteristics that determine how well a material will atomize. how well it will "flow out" on the work. and the lype of equipment necusary to mow it. Viscosity control, therefore. is essential in obtaining a uniform &ish quality fmm day to day or job to job. Your material supplier will recommend the best viscosity 10 apply the material chosen for your job-stick with it. There arc many methods by which viscosity determinations are made and each method may have one or more units of measurement: I . The measurement of resistance to movement of a device through the material in a rotary maim (such L( a paddle or fork). is expressed in Krebs Units (KUS). 2. The resistance offered by the material to a falling body passing through it. usually a ball of specific size and weight. is Poise or Centipoise (100 poises). 3. The lime necessary for an air bubble to rise through a quantity of the material in a tube is the Gardncr-Holt Bubble Method. 4. The time necessary lor a given quantity of thc nutcrirl to flow through M orifice of a specific size in thc batan of a special cup is thc Efflux Method. murial. 3. Raise (or h e r ) temperature of test material to standard I d (lldeg. F nxanmcndcd). 4. Fill cup: a. khn-submerge cup in material. b. Ford-Pour material from container into cup until it overflows into surrounding reservoir while simultanmusly holding a linger at the orifice IO prevent flowout. Place conuim under cup. 5. Release flow of material and simuluncously trigger stop watch. Keq eyes on the flow,nu the watch. a. Zlhn-Raise cup out of the material. vertically, by IYlmns of split key ring. b. Ford-With quick movement remove finger from mi6a 6. When solid stream of material pouring from orifice 'brutr" (indicating p w g e of sir through orifice). slop the vuch. 7. Record slopwnch elapsed time, e.&. 20 x c a d s . No. 2 wn. 8. Rcfer to the ctun (opposite page). 10 determine viscosity fclatedtoclpedtimc. --/ 18 VISCOSITY CONVERSION CHART FOR MATERIALS AT 77" E WITHOUT SPECIAL THIXOTROPIC CHARACTERISTICS I L I G H T CONSISTENCY Watery or light oil IVIKmalerials with translucent or very line grind mlor. I MEDIUM CONSISTENCY Light creamy or thin syrup t y materials ~ with medium to fine color or filler orind. CAUTION Your ~iscosimeteri s a precision instrument requiring careful handling, cleaning, and storage. Improper care will adversely affect i t s accuracy. HEAVY CONSISTENCY Fluffy cream or slow pouring syrup type materials with medium lo coarse mind color Compressed air spray gun principles 1 GENERALDESCRIPTIONOF AN AIR ATOMIZING SPRAY ~- GUN The b i c function of an air atomizing spray gun ir to use compressed air to break up material into s m d droplets and give these droplets direction. The spray gun itself rovides taro convenient valves to start and ntop tie flow of com ressed air and fluid. The mixing of air and m a t e d m take lace outside the s ray g u n between the "horns" o the air nozzle. T?his is described as "external mix atomization". If the mixinn of air and material rpkes dace inside the a i r nozzh of t h e y a y gun. we 'use the term, "intemd mix nozzle Material can be brought to the spray gun by creating a vacuum at the face of a siphon type extemd mix nozzle. This vacuum draws the material through a tube coming from an open top m a t e d container to the air nozzle of the spray gun for atomL0tian. This method of atomizPtion and material delivery is d e d *si hon spraying". See Fig. Y1. When heavier fluids or !&her production rates are requirrd. the material can be pressurized and forced up to the air n o d e for atomization. This method is then called "pressure feed Sprayhf. n. beloar. A. Heavy Duty Production Spray Guns: P 1. High volume of materid output, 2 Rugged construction. 3. Must be able to handle a wide range of materials, 4. Rovide the widest range of controls. . - SPRAY GUN SELECTION The selection of a spray gun is determined by its function or end use. The most common t y p e s of air atomizing spray guns and their. features are listed 6. E w of operation, 6. Modular design of components. B. Standard Production Spray Guns: 1. Performs the m e as heavy production spray guns; normally tokes the same air and fluid nozzles, 2. Lighter construction C. TouCh-Up Spray Guns: 1. Light weight, 2. Light construction. 3. Handle only light materials, 4. Small physical nize. D. Heavy Fluid S p y Guns: 1. Rugged ermrtruetim, 2 High apreity nodes, 3. Handle heavy materials. E. Automatic Spray Guns: 1. h e requirements and nodes as for production type sprny guns listed plwiwsly, 2 Spray gun is operated by remote mtrol. F. Special Purpose Spray Guns: 1. Air blow guns, I 2 Caranshingguns. 3. En* dealling guns, 4. Rold muking, 6. Extension pole guns, 6. Flora guns, 7. Flock spray guns, 8. Plural component spray guns. G. Special Spray Gun Attachments: 1. Fluid strainers, 2. CirmLting connections. 3. N o d e extensions, 4. Extension arms. 20 ni. mms of A SPRAY GUN The basic parts of a modem production spray gun are outlined as follows: Item Description A . _- The air nouk of a S D ~ run Y is the most important part of the entire spray gun. The air n o d e directs air jets to ptomim tbe Buid and to give the particles velocity to reach the product surface. B Thtprrid nouk is the a e c d m a t i " ( m t part of a spray gun, for this part pmvidea a mhl for metering matvinl delimy. C Needle assembly acts aa a s t o g s u r t valve for the m a t e d flow thmugh the s p n y gun in emjunction with the duid n d . D sidc porl tonhol or fan control reguhtas the spray pattern width by controlling the air supply to the % o m " of the air d e . E Fluid control aasembly pmvidas mechanical pressure on the needle valve so that it will dose when the trigger is released. F The m y gun body h o d & is deaigned fa hold d the oprts and mve the owntorahnlanmi and cothonpble L d l e for-sprayiug. G Air inlet to provide a connectingpoint for the air hose. nonnallv 114 in. N.P.S. H Triggcrectivatds and controls the air and material movement to the nodes. I The air valve controls t h e air movement through the spray gun. Fluid inlef connecting point for siphon cup or J material hose. normnllv 318 in. N.P.S. The versatilit? of using compressed air to atomize material has made this type of spray gun the main means of applying a mating in the hishing industry today. These spray guns can handle all types of sprayable liquid materials and can be controlled to such a degree as t o pmluce the hest possible 6nish on a product, with lowest possible equipment cost. This type of spray gun is a precision tool. The rpray operating efficiency is dependent upon a knowledge of proper s p r q gun selection, spraying techniques and maintenance. W. SPRAY GUN DESIGN A. Bleeder or non-bleeder type spray gun. Most production spray guna are non-bleeder type. Air flowthmu h spray gun only by the action of the trigger. B eeder type spray guns are normally used with d portable air mnpreMor to maintain eonatant pressure, and prevent the polaibility of rtOrtiag u p tbt compresror against a load. Air discharges from the air nozzle continuously. B. CMStruction Features: 1. Removable head, 2 M d g e type valve rssemhlies, 3. Adjutable needle .ssembly, 4. Triggw bearings and a wear plate. , C. bterid Used In Tbe Gmatruction Of The Spray 'i Gun: 1. utr", 2 Bnss, 3. st.inless steel. D. Method of Construction: 1. Drop forging, 2. Die asting, 3. h g h ensting. E. Spray OpeRtms Features: 1. Weight, 2 Location of controls ( h tor rear of spray gun), 3. Handling ehpReteristics, 1. BPLnce. F. Design Features: 1. Number of pnru, 2 Ease of air flow through spray gun (pressure drop), 3. Air nozzle and 5uid n o d e desim. 4. Protective finish. 5. TvDe of material used in construction of fluid ~ ~_. Compare these points to the expected service one may receive as compared to the initial cost of the spray gun Seleaed. 21 V. UR NOOLES 4. On p m u u m feed air noules, a second set of holei may be indexed 90’ from the containment holes. Theae holes are called angular converging holes. This i, &led second stage atomization. (See Fig. A 4 , these air pas-a d d additional force to help atomize the duid stream since in a pressure system. the fluid comes aut of the n o d e at a higher velocity than a siphon sptem. The air m m m e n t a t thia point, creates an air cushion at the face of thc nozzle; thh helps to keep the face of the air d e dun. 6. The air piwagmap in the “horns” (sometime all4 ”wings” or uears”h are d e d side port jeb. (See Fig. A-3). 6. The side port j e t s of air, strikes the fluid stream just ahead of the second stage atomization point. The primary purpose of these rt air jets is to form or shape the air ?%Kid stream into a “fan” shape. Some additional atomization may nlso result. 7. The &e of the “fan” width a n be controlled by regulating the amount of air diverted to the side-port jets (See Fig. B, Side Port A. Airspnypm n d u fall into tkfolla6iingate porig: AIR NOZZLES r i EXTERNAL SIPHON FEED 1 PRESSURE FEED Cootrol Stem). FIGURE A - EXTERNAL MIX ATOMIZING HOLES SIDC.COR? COUTROLKNOW B. The control and operation of these air nozzles depend on many factha such u: 1. Pmper trpe of air n d e , 2 The 8k.e selected, 3. SPnY gun d. 4. Method of feeding m a t e d to the n d w . 6. Material to be sprayed. 6. Setting of p r e s ~ ~ r air r s and fluid, 7. Adjustment of spray gun controls. C. External Mix Air N o d e . The most common type of air n o d e used today is the external mix n o d e . The reason for ita wide acceptance is that it will produce the best atomization which,if controlled properly, wiU gin p u the best possible finish. These air nozzles u e designed~toput compressed air to work in the following m e r 1. The annular ring, the space between the fluid nozzle and the air n o d e , provides a column of air to s m d the fluid stream. (SeeFig. A-1). 2. The fluid 6tream expands and mixes with the air coming from the annular ring of the air nozzle. This is d e d first r b g c atomization. 3. The holes which we in a straight line with the “wings”, “ears” or “horns” of the air nozzle are containment holes (See Fig. A-2). a To keep the spray pattern f ” expanding too rut. b. To keep the %oms”dean. 0 ANNULAR RING ARWNO THE FLUID NCZZU TIP. @ *‘CONTAINMENT MOLES” @ ‘WNCS“. “HORNS’* OR ”EARS” @ SIDE*PORT HOLES @ ANGULAR CWVERGING HOLES 22 D. The Evolution Of An Extend M i Air Nozzle spray Pattem. The above illustration represents the evolution of a spray pattern h m "round" to "fan". Assuming that the fluid and air pressures remain constant for aIl the patterns, the mwt of fluid deposited in each instance will remain constant. "Ius, it can be noted that as the area of the pattern increpses, the fluid fiLn coating thidmess must deerense. The duid film coating (or fluid deposit) is measured as mil thickness (1 mil equals .001 inches). For example, if the pattern on the extreme left hns an area of .800 square inches and a thicknw coating of 4 mils, the pattern on the extreme right with an area of 1,600 square inches will have a thickness mating of 2. mils. Gencrplly, proper atomizntion can be achieved in any pattern, dthatgh with some nozzles and fluids. minute adjustments of fluid and air pressure may be necessary since more overspray and solvent flash-off will occur with the fan pattern thu,with themud putern. Since this fluid is 'lost" and not deposited on the surface being ~ p ~ y endc,t d 5lm thickness in di cases should be determined by measurement. Also a dry Alm will memure leu than a m t 5lm because only the "solids" remain after the solvents have enprated in drying. SIPYON E. Determining Siphon And PRsSure Feed Extend Mix Air Nodes. External mix air nozzles break down into tam types. They are either siphon or pressure feed. The siphon feed n o d e can be determined by the fluid n o d e protruding beyund the face of the air nozzle. The angle at which the side port jet holes are drilled in a siphon n o d e is different from that in a pressure nozzle because a vacuum must be created at.the face of the siphon air n d e . (See illusvations at right) . Pressure nozzles can and s h d d be used with lmer atomizing air pressure since the vacuum condition is not required as in the case of the siphon node. Pressure spraying is more efficient, faster and cleaner. Siphon spraying is best suited when s d quantities of materkl are being used such as in an automotiw body shop. Resure feed &e horns are shorter and the face hns additional air holes to help keep the face of the nozzle clean. The side port jet angles can be drilled at a closer angle be cause no vacuum must be created at the face of the pressure feed n o d e . The numbering designation will indicate whether or not they are siphon or presIurr ~ o r ~ l by e sthe letters "S" or " P stamped . : 3 the n o d e . F. Requirements. Advantages And Limitations For External Mix Nodes. 1. Equipment requirements. a An air supply capakde of meeting the repuirements of the air nozzle. There a r e many different types of external mix air nozzles available. These nozzles difIer by the amount of air they consume, spray pattern size and materials they uill atomize. Sales literature and engineering data must be checked for 23 thlinlomstim b. The sLr no& m& be dedi& m for praanac rpnying. nozdea do not produce very 5ne atomization but b v c bigb production apabiitiea and am Nitable for mwt msintcmn punting work. Not dl materide un be sprayed taith thin type of nozzle. They are limited to dower drying materials becruse fast dqing matednh tend to plug the exit bole. A. The equipment requirements, advantages and limitstiia~for intend mix air node pre: I. E&"t Rqimmta: a. Thin type of air nozzle can only be used witb a p r e m r e feed system. h. The nozzle requires the use of low air and duid p r r s w t k c Tbe lir and 5uid pressures must be closely rrgul.ted. d. The air .ad fluid preu8w-e mt be appmxW y equal ai tbe n o d e . e. Intemd mix n o d e s are available in many rizes and constructed of many types of the choice is dependent upon the mate* kind of materid you arish to spray and the rate at wbihieh p~ wish to apply it. (Refer to dcs .ad enginering bulletins for selection for liphm c Pressure feed nozzles require that the material be supplied under pres." to the s p n y P. d. Pressure feed nozzles omnot be wed for e. dphon feed spmyinp. Siphm feed nodes can be used for prranm apraying hut the spray patem drc w i l l k smaller. Siphon feed nozzles are often used tor p~surr feed &g of sdbwivea. 2 Mvmt.gas. ExtunJmixnoszlasernpmdueethe~oest possible hi&mnldng . it ideal for furniture Md epT finishing. b. This air nozzle baa great flexibility in eonbullingthe spmypattemsize and thedegree of paint u0"L c A siphon nozzle can be us€d for drawing motelinl hum a container and atomizing it. 3. Limitations. a. Theyrequirelnrger~titieaofair. b. T b e y o p r p t e u n l n t i v e l y h i g h a i r ~ . e.. They maycreate large amounts of overspray a d rebound if air md flnid pressure -e+Y-. daw. 2 Advantages. a. Lorp volume air emsumptian (cubic feet per minute). b. Lorpsirpraaure(paundspersqunrrinch), c By ruinglaw air p ~ a s u r rand fluid p m s u r e tbemrapmy or rebound will k minimal, d. clp.bsity of higb Rtc of fluid cutput, e. Cm produce Lge spray pattenul. t Hw the ability to break up heavy, filled moterkb, g. Noarle tip can be replaced at low east. 8. Limitrtioas: a. Thia sir n o d e produees coarse atomhtion and is not recommended for extra fine VI. INTERNAL MIX AIR NOZZLES In M intend mix air nomle or l w preasrne &e, air and fluid a r e mixed in a cavity inside the air nozzle before being released to the atmosphere. These air n o d e s have eitber s round hole or a slot from which the mated sprays. When tbe mate4 lesrns the air n o d e it will "fsn cut"sndumf0rm toa ahape as determined by the air node ope*. -9 b. Some fast drying fluids have a tendency to dog tbe exit slot or bole, e. Tbere is no control except by n o d e seleclim for the spray ppttem size or shape. d. Noak wesm due to abrasion. Tips must be rrplsced. B. Stutup proeedurc fw internal mix sir nozzle. For maximum efficiency, both the fluid pressure INTERNAL nix and the air pressure should be the same at the nozzle. To initially adjust, always start with the air p m u r e . Tben d w l y Rise the fluid pressure, gradually lowering rhe air pressure until the desired flow rate and spray is reached. NEVER open tbe duid valve &ut, since without air atomization pressure. the fluid will tend t o back up into the air psaages of the gun. AIR NOZZLE These air n d e s find wide acceptance in the maintenance psinting market for applying mating to Lge s r e a s very rspidly. These internal mix .air 24 M. S P E C U E F F E C T U NOaLES specid rffect l l r Wrrles ue gelnnlly prrawe fed These nouls are upd to meate rpckl effectr rlth certdn types of mrtnirk by using extremely low ah mi fluid p m s u m which have been accuntely COP trolled. These spedd effects .I(m d y sprayed to a t e exotk type rlndom rpng patterm mch n wiling. iprtter and dWeadng (sometimes called "fly rpeeking"). ThMZZlS UC M h b k Md &tWchangeable with d.adud production spny pas No rpeid cpny p n LC requlrrd Thaefote an .It nonle with a larger C.F.M. rating wP1 provide a fwer nt.of application of the uumiJ on the Nbrtnte. i t which the air b. The &her the Ilr pimt2k must operate, the mter the air l n o a a . rir volume (C.F.M.) re. L putted llm Lacrgwr EXTERNAL MIX AIR NOZZLF. n INTERNAL MIX AIR NOZZLE r A. Eguipment Requizemnu: 1. A specid mix nozzle kit for the tjp of effect you want to achieve, mounted in your rpny ADVAMAOES LIMITATIONS Coaru atomtauon F i x d m y pnnn Fim Atomiution Control of spay p n r n .U* Iun, 2 Two air ~ e g ~ for h precis t ~ ~ control of both lir lnd fluid preasums is required. Air m I a t i p will v m r Rmurs f n d only Siphon and wmura m z z l n .milable 3. A one or two quut p n w r e cup, or pressure Unk. depending on the amount of material that is required to be sprayed. B. Advmtapa: 1. The ability to n u s produce a rpeid effect, 2 Added rsles appeal to a product, 3. Hiding ibUlty to cover defect& LIMITATIONS ADVANTAGES Rquira mors C.F.M. 01 air Worbwrirh hi$! air pmure only Hximum o n n p a v Minimum lilm build P Pfl U n i r " size rpw Rquiri 1 6 s C.F.M. of air R q u i r n low air P.uuII Minimumowmcay hbiimum film build PIPE hiin'" size I P ~ V pnnn m6Il C. Limitations: The spray opentor must be more highly skilled when applying these eftear. in order to iru&Wn @me uniformity. . WII. PROPER AIR NOZZLE SELECTION A The following points must be *en tion when m k a i an ah n d e : into oonridm. 1. The type of matexid you M Eoingto spray will determine the spny pattern size .nwell u how it atomize& B w u w diffmnt nvtcrkls rill cheu or tea^ spur according to their cohaivr NIUR. 2 The volume of air you have available In C.F.b!.not prasure. Do not choose UI air wale r l t h a cubic foot per minute r a t i i wbich k luger than that which your m m p n s o r a n supply. A ruleof thumb you a n foilow is that a one home power electric mL0r driven comprrsDr W~II provide four cubic feet of .ir per minute at a hundred pounds per square inch 3. All air nozzles will not physically flt over Iu fluid nozzles so it b nerrs6vp to select t h e e item LI I matched set.hpr nutching of air and fluid nozzles mud be checked out on a chat propided by the equipment mlnufictum which shows 111 avallable mmbirutiow 4. The higher the C.F.M. rating of M air nozzle, the m a t e r the volume of matn*l that the air nozzle k upable ofatomizing. 25 Fluid N e t d m 0 1 H k s Rang# Idnmtn) .022-.028 .w.o52 .059-.070 .o86.110 .115.5w iw v Thin Thin hilum VV I Hrrl vwb v y U. ACnOM Water 5 A E No. 10 oil SAE No. K ) oil VSChnC 4. TO d e t w i n e nuid now nt.for p-m fw spriylnl, &ut offthe itomiring air and puU the rpny gun triggn to bleed the nuid Into a graduated container for OM minute. The following flow nte chuI for i 20 r c o n d mta*l wing I number 4 Ford cup, tt t ternpentwe of 75oF, m y be of some help In pndkting now d. A NIU of thumb t h t a n be followed with clandud rmterbk wben rtting resum k t h t rlth the rL ~ p p l ycut off the p i n t rill flow In imlld a c m a T h t fluid strum lhouid begin to bend down ahout t h m feet from the spray pa Anyrbl In m e % of t h m fwt mu Loo higb i%id velocity. (seer i m below). ntar Delivery in Ounca Pn Minuta .059 24.0 28.0 3l.O 40.0 48.0 X. NEEDLE ASSEMBLY The b u i c function of the needle is to shut off the h i d flow. It rL0 can be wed to meter the makrinl pming thmugh the fluid no&. (c2sabove) Needle lelcaim t bwd m: 1. Th &le must be nude of the proper mpterid and the right *Le to match the fluid nouie. L Standard needles i r e corrosion resistant. huded stainless &el. b. Abrasive resktant needles ue tungsten carbide tippd. c. Needies which require positive shut ofr u e nude of nylon. 2 Tbc d e is part of amrtrhed et urd if not the ight *Le it aill caw problem: L Leak at tbe h i d n d e . b. Split the d of the fluid node. c. Turnmtbeduidheforetherir. d E x d n prorwion of the needle tip which rill mIrkt fluid deli-, e. A nqcdk tip which Q too *rge will not dun out tbe fluid d e sri5n when luted. 3. Needle idjultment is mquimd on certain spray gum to compensate for wear. The adjustment is accomplished by changing the position of the lboulder .nd locking nu& (See right band figure belW.) a. Determine the amount of adjustment re. qulcd-lund guns should hove an ur stroke of 3132 of an inch (ipprox.) and automatic 8pny gum .bout 1/16 of an inch (see figures helm). h. Looren the lock nut and move the shoulder forayd to shorten the air stroke or rearward to kng'tben the stroke. Try the needle in the r p n Y gun. c. Adjustment is by trial and ermr-when correct position is found tighten the lock nut to hold the shoulder nut. 5. For i more =curate reading of fluid delivery and prcrsurr i t the inlet of a rpriy gun for i puticulu size fluid wzzk otUice i t icertain IMtRirl viscosity, the following folu c h u t ~ showing the most common &e nuid nozzle orifices used will be of ulstanca, To use theae graphs one must measure tbe fluid d d i r a y and i t the inlet of riscohity to find out the prthe spray gun When the rqulnd delivery b known for i particukr vimsity mitdul, the fluid plegurr rad nuid nozzle oriflee dzc in i spray gun a n be determined by drawing &sight lines connecting the known nlua to find the unknown dues. Example. wb.1 &e fluid nozzle will give i28 fluid 02. per min delivery i t 12 P.S.I. fluid prrrsum with 4 15 m n d material? Answer.052 om-. 6. Material from which the nuid nozzle k m d e will nry depending o n the ehurc(crlLia of * the fluid to be sprayed: L SUndud p h t s use hardened rbcl norrla. b. Corroave mtnws (water hued, 4etc.) use Iwnles steel nozzles c Abrrzivc materials (mamkr. etc.) use tungsten arbide quipped w a k C. Control of nuid flow: 1. Siphonspraying. L The nuid n o a l e orifice. h. The idjuament of the nuid control on the Y" gun. 2. Reswrerpnying. L The nuid nozzle orifice. b. The nuid presure setting. Note: Not to ex. ceed 18 P.S.I. i t the spray gun inlet for standard type of materials, excesive nuid pressure causes high fluid velocities which prevent the lir nozzle from itomking the nuterial properly. Always ur the west possible nuid nozzle orifce urd the low& possibiefluid pressure to give you the mrteriaI delivery you require. E. The adjustment of the fluid control knob on the spray gun should be in the maximum open position on I pressure feed systems This is just about that point where the screw threads appear on the nuid wntml knob. The nuid control knob is the irrt Item t h t is adjusted for fluid delivery. 1/16'. 26 * XI. SPRAY GUN CONTROLS A. Operator Spraying Techolqua The ntrr ? q u i z " Y propa handling of tbe spny pa The spray p a should be held papendieulu to the ruzfece being covered. and movd In even stroke p a d e l with the ruzfrec. The stroke rhould be stuted kfore the tzigger k pulled Md reluvd belore the stroke k flnkhed. Thk is easy ud gives accurate control of the ~ p m yp n and m t e W The distance the spray gun is held I " d a c e is determined by the materid a d a t o m . tion praacre, and may wry from 6 to 12 lncbq but the material deposited should always be om ud wet. Overlap each stmke by 50 per cent over tbe preceding stroke to ohmin a unlform llnih For additional information on rpnyitqtechniques see Training Divkion Bulletin No. TD49.1 per. taining to this subject Ya.*i.l cmnw I.2I.l. Spray width *i""lM"I. C. Siphon Spraying. Set atomhtion pressure at appmxinutely 25 P.S.I. and kst spray pattern with fluid control knob opened. If material atomization k tea come, in. crease air pressure by 10 P A L and est spny pattan 4Jn Continue this untll you have 50 to 60 P.S.I. at the spray p n If material rtomiwtion is ctii too muse dose (turn dockwise) the fluid control knob on the spny gun slightly. Adjust the rpny pattern width and repeat adjustment until a proper spray pattern is achieved using the lowest possible ah premtre that will produce the desired fin& Additional thinning ofmaterial m y a h be WUind. D.Rnarre Spray@ Select conect fiuid n o d e orifice size using the previous fluid nozzle seiectin charts and set nuid presure for required materid delivery. Set atomi. a t i o n air at about 25 P S I . and test spray pattern. If spray pttern is too come, n*e ah prepsure. Adjust desired spray pattern width, repeat spray gun adjustments and nuid pressure fating if n m s u y . In some inrtuKes material m y require addltbnd thinning. Remember keep fluid control mew in "open" position Use mmct fluid nozzle size and pmper fluid pressure setting to obtain pmper flyid delivery. NOTE: To reduce "over. spray" and obtain muimum efflciency. always spray with the lowest posihle atomization air pressure and the lowest possible fluid presrure that will give y w the required finish you ue seeking. E. Spray httm The spray panem of M external mix nozzle on a spray gun quipped with a fan control k variable from r w n d to fan with all spny patterns in WRONG RIGHT E. Adjustment of Spray Gun Controls a. The proper adjustment of spray gun controls permit a spray operator to control the size of the rpny pattern and the m o u n t of material coming out of the spray gun h. The spray gun controls will he louted on most spray guns in one of the three following positions: between Spmy -,I+ odiu.tn.nt. Turn v q h t for round. 1.h lor Ion In normal operation, the wings on the nozzle are positioned horizonrally IS illustrated here. Thic I spny pattern which provides a verticai ~ Ushape gives maximum coverage IS the spray gun is moved hack and forth pmliel to the wrface being 27 M. S P W Y GUN INSTALLATIONS There uc nuny ways in which a apny p n CUI k inlulled .nd used. Ihe rynun I c l d will *nd on the amount of material )w wish to sptay, che fluid viscosity and the atomizing air MI haw ~ i l a b l e . SIPHON FEED HOOKUP For limiud spraying md toudwp. Atomization air is Icgulated at exmaor. Amount of fluid and alomiutitm is adjusted by fluid contcol ccmw on gun. PRESSURE FEED CIRCULATING SYSTEM HOOKUP Atomization air rcguhtcd at extractor. Ruid pressure regulated at nuid regula~or.Recommended for heavy F" .*s INITIALLY-Always prepare paint to be sprayed in accordmce with MnnuJncrurrr's Insrrucrionr. Material should always bc h n e d h. cmsiamcy of paint ud air presuuc. . PRESSURE FEED CUP HOOKUP Atomization air is regulated at exmc~or.Fluid p m ~ ~atr e cup regulator. Atomization air pas= thmugh cup replator. T h i s method is ideal for fine finishing with limited spraying. Pressure cup also available las cup Icgulator. Fluid pmSUR q u a l to atomization pressure. For heavy fluids ud internal mix nozzle spraying, fluid adjuned by conml screw on gun. .".I E PRESSURE FEED INTERNAL MIX NOZZLE SET LIP For maximum efficiency. nuid and air pressure should k idendul at the nozzle. To set up chis caditton easily. Jwys introduce air p s u r r fim. Then. slowly inuoduce fluid pressure while simultaneously lowcring air pmsurc until UK desired flw rau and spray p a " are achieved. " E R introduce fluid pressure first since, without air pmsure. fluid will back up into.the air passages of the guo and caw subsequent malfunaioning. XIII. MAINTENANCEPROCEDURESFOR THE AIR NOZUE. FLUID NO=€ AND NEEDLE ASSEMBLY PRESSURE FEED TANK HOOKUP (Si& R r g h o r ) Atomization ur is regulated .t exa-". Fluid pressure at tank regulator. This system is ideal for medium productm spraytng. PRESSURE FEED TANK HOOKUP (Double Regulaior) Atomizatioi6air and fluid pressure is regulated by two individual air regulators on unk. This is proven highly efficient for portable painting operations. A. All air nozzles, fluid nozzles and aecdla. regardlas of h e i r cost, LIC prccisicn made and care must be ' taken when handling thcw puu. 1. Do nol makc m y Illeratioar. howcwr slight; these could Uuy finishing difficultia (with the exception of d l e adjuament). 2. To dun air and fluid nozzles. soak the parts in rolvcnt to dissolvc the dried material on them and blow dean with air only. 3. Do nu probe m y of the holes of the nozzles wth mcul insnuments. If you feel probing is necessary. w mly I tool that is softer than brass. 4. The needle assembly m u be adjusted so that the lir turns on bcfore the fluid docs. 8. To chcck out a spray gun properly and be certain that the air and fluid nozzle uc functioning correctly. a sene$of spray panem checks should bc made. Stan by opening the side port control io the maximum open position. Turn on the air supply using B h air pressure setting. then turn on the fluid supply if needed. Increase air pressure in 5 P.S.I. increments until che de. sired spray pattern is created. Increase fluid prcrsulr slwly if needed to hel,pbalance out the spray pattern. Trigger the spray gun in short bums on a dean surface and wtch the spray pattern lake shape. (See Page 41. TYPICAL FAULTY AIR NOZZLE SPRAY PATTERNS I cluu cmlction 1. Drld paint in ow of the dde port bola of air male. 1. D M i v e print in dde pod hole with thinner; do not probe iu any of the bola with a tool buder than brui. RtfWl ~ e”’? -9 e:*:. I ‘- c,,-‘. I ... I .... I 1. Fluid build up on side of fluid mule. 1. Remove llr m a l e and rip 2 D u ~ p a dfluid wuk b u m spny v drop@. 2 Replace damaged fluid m n l e . Lhprrrurrtoobu. 2 Spny pattern too ride. 8. Fluid n l c a u too ~ low. 1. Reduce rir pressure. 2. Reduce fan width. male. 2 Usesmrlln fluid nozzle n r l l i , lower fluid mcuuw. fluid 1. Air mtahg tbe fluid supply could be auaed by: Loor fluid nozzle, or mt sating pmpedy due to dbt. b. Loose or missing packing nut or dried nuid packing. E Fluid connection -l. L b. It dissolves the lubriatlon on the spray gun awing the purr to wear Iura. L It causes dbt or rolkds to build up or become bose In the dr pasages wbicb will m n t i m h t e tbe linkb. 6 It h p h thc opntion ofthe spray gun. 4. Wash down the outside of the equipment with mlvent dampened rag% XIV. GENERAL MAINTENANCE PROCEDURES FOR SPRAY GUN A. Pointers on cleaning a apny gun When a spny gun b umd r i t b a riphon cup. thinner or suihble alvent should be dpboned through the spray gun by inserting t h cup tube into an o p n top container of that wlvent. “rigger repeatedly to thoroughly nu& the pastageway and c l a n the tlp of tbe needle. C k a n i ~ r p r a y g u nused with apt 0 m n n t on t.+ and l o o m air nozzle. Hold a pi& of clotb wadded in tbe hand over the llr nozzle and pull the trigger. The llr wlu back up through tbe nuid nozzle and force the fluid in tbe hose back into the t.d (mmetimes r d e m d to as ”blowing back”). Next, put enough clean thinner or solvent into the tar& to wash the inmior of tbe bore and spray gun thoroughly and spray this througb the spray gun until it N N clean. B. NOTE: It ic extremely poor pnctice to h m e m the entire spray gun in thinner. When this is done, the mlvent removes the oil In the leather packings and causes the spray gun to “spit and leak”. 1. Immerse the rpray gun herd untll the solvent just covets the nuid inlet connection. 2. Use a hau briale brush with solvent to wash or scrub off any accumulated paint on the spray gun. 3. Do not place the entire spny gun in solvent v l h beau=: L Tahten fluid wzzk. or dun fluid nozzle 8eat area. b. Tighten packing nut. or replace missing or dried fluid packing. E Tighten 111 fluid supply mnnections Inding to m n y gun. L It dirsolves the o h in the leather packhgs, ausing them to dry out. 29 L- 5. Lubrkatbn of cpny gun &odd be done d e (preferably before using). Oil parts (a) thmugh (d) with l i h t machine oil. CAUTION: Neva use lubricants containing silicone, 15 ailimae m n o t mtisfrtorily be flushed from cpny (un or h o r a once contaminated. L Fluid needle packing. b. Air nlve packing. e Side port control packing. d. m e r pivot points e. Cort the needle vdve " b l y spring with petroleum jelly. C. All put sheets packed with spray equipment should be retained for future reference for the purpose of odering spare parts and performing rmintemee operatiom When corresponding with the equip ment manufacture In the event of difficultis, to aide in the solution of your problem p l u v indL a t e the following points whenever poarible. 1. Spray gun model number 2. Nozzle r t up. Air-FluidNeedle3. -re feedSiphon f+4. BleederNon bleeder5. Air S o w * CFMPSI 6. Type paint used I . Type reducer used 8. Vismsity or reducing ratio 9. Type product being punted 10. Production ntc 11. Any other Information felt p a t i i n t , rucb u - prrrarre SettingE. XV. LIST OF COMMON TERMS USED WHEN DESCRIBING SPRAY GUN PRINCIPLES SPRAY GUN: A precision mol desicned to spny rpply a mteri.1 using one of the thm brdc principles to atomize the material. AIR NOZZLE: (Air-Chp) The put of the spray gun which utilizes comprersed air to atomize and dimc the material to the work surface. FLUID NOZZLE: (Fluid Tip) That put of a spny gun which directs the fluid into the ah e",md du,r m e s to porition the air nozzle. NEEDLE VALVE: That part of a spny p a wbicb regulates the material pasing through the nuid nozzle. TRIGGER: O p m t e s the ab vdve id fluid needle valve. FLUID CONTROL: Controls the volume of fluid by restricting the movement of the needle vdve. SIDE-PORT CONTROL: (FM Control) Controls ab flow to the h o m or wings to regulate pattern size and hpe. AIR VALVE: Turns the air on and off. FLUID PACKING NUT: Provides controlled pesp~re on the packing. preventing air from entering the fluid pasage or fluid from leaking out of spray gun dong . the needle. LUBRICATION POINTS OF A SPRAY GUN: a. Trigger pivot, b. Fluid needle packing. e AlrnJVrpctinl. 6 Fluid needle sprlng, e. Sidcport control packing. SIPHON SPRAYING: When m t e r i d ls fed into a spny gun by atmospheric pressure due to a putial slcuum created by the design of the air and fluid nozzle. PRESSURE FEED: Term used to describe the procm of force feediw material to the spny gun using a pressure cup, tsnk or materLI pump, used for luge volume spraying or when the numid is too heavy to riphoe BLEEDER GUN: Fmvides uniform ih prmure at the ah mule of spny gun; air constantly flows through 41nazzle of spmy g u e (Recommended when small portable ab mmprePors are to be used.) Has no air vdve unully. NON-BLEEDER SPRAY GUN: Air flows through spray gun only when trigger is actuated. EXTERNAL MIX AIR NOZZLE: Accomplisher a. tomization by mixing compressed air and fluid out. side tbe air nozzle by the action of air jets from holes which ue drilled Into the air nozzle. This method k normrlly used when fine finishes are required. SIPHON NOZZLE EXTERNAL MIX: Designed to cmie a vacuum in front of the fluid nozzle and draw rmteri.l from a cup by atmospheric prwure. This nozzle un u s l d y be identified by the fluid nozzle protruding beyond tbe air nozzle. Most Binks siphon nozzles ofthis type CUI be identKHd by the letter "S" in tbeh nomenclature. (Example: 66SF.) PRESSURE NOZZLE EXTERNAL MIX: Requires qrrzcure to feed the rmterbl to the fluid nozzle. May be i d e n t K i by the Iztm "P" in the nozzle d w tioe The fluid M Z k ~flush with the air nozzle. (Example: 66PE) INTERNAL MIX AIR NOZZLE: Atomization k obuinedmd spray panern k formed by tbe mixing of compressed air and fluid ilcjde the air nozzle. These noaks usually a n be i d e n t i f i by a dot or round hole in the center of the air n o d e . Up~dIyused to spray heavy mintemnee paints where a fine finish is not required. ADJUSTABLENEEDLE ASSEMBLY: One where the rhouldn of the needle is moveable to compenvte for wenr as in the Binks spny gum MUSHROOM NEEDLE, A needle with I flat tip instad of a tapred (point) one u d with fluid nozzles with luge openings, which are made to spn? henry mteri.lr FLUID CONNECTION: The point where fluid hose or ripbon cup connects to the spray gun. usually 318" &ugh1 pipe thread. AIR CONNECTION: The point where the air hose mnnects to the spny gun norrmlly at the bottom of tbe cpny gun handle. Urudly k 114" straight pipe thrud. AUTOMATIC SPRAY GUN: Used for automatic spraying applicatiorrr where the work k carried past the spray gun. I Fluid Nozzle Selection made e r m m ~ . N O t t W m u c h t r o u b k i a r ~ ~ u n t e r e d f ~ v ~ m a o ~ ~ ~ l o ( OEach ( horizontal bar on the chart npnsents the range of nuid practical lvlwkdge a d experknce with the nuny &ea of p~rrunsthat can M u608 lw each size of fluid nozzle for nui8 nozzles available and the tremendous variety of coating optimum apnying. The 18-psi maximum m u w e listed in materiaIa.Howewr.forthe haa info“,me p r o p o r ~ k m uch bar wu ChOMn bcuutr. h moat -a, any higher u n M quite a myaiery. prosrum brings poor atomkation at the eir nozzle. a6 the axil mlocny olthe finishing malerial leavingthe nua n m e oMce The choice of a fluid nozzle b dictaled bythe amount of coatb axmaaiw. ing mdlarkl to be apmyad per minute, and the virc0aHy.Th. greater VM amount to be sprayed or the heavbr the viscosny, An eumpk of uring th. chart follows: H a 2 0 - w ~4 1 Ford the larger me fluid nome orhic. must M. matrri.1 ia lo M used an8 26 01 per m h llcy rata b deairee. 10lloWthe26-02lineuplntothemiddl~~iono~tnsctmrttor Two primary mahodr of wntmlling the amount oi finbhhg mint when il intenMtl wlth th.three ban tor me 0.046-In.. malerial 10 be ~ p m W are by th. proper choice of th. nuld The 2&02 vertical line 0.052-In. end 0.059-ln. (luM -a. nome orihm and bythe preuure exrrt.d on me material bye mms “ u g h a11three banb best cho~mofe nua nome preuure 1.nh or pump. lor them wndabnr would be th. 0.052-in. &e, M me msAlthough most spray gun mnnuhctunrs have quRe I raw ol sum to give IM2 6 a fiow rate ia abcul mamy between me fluid orifice aizes. 0.022 to 0.500 In.. generally, this e r t i i pi minimum and maximum owraling nnge. Soiecting the deals with t h w commontothe spraying Of l a q u a n , O M ~ ~ i s 0.046-h. nozzle would be umirr.as the r e a u l d operating and umihr coatings. p n u u n w w M ba too hmh. chooring th. 0.059-in. n e e As a guide m M+ accurate ulection of a nuldnord..me chart wwldalw ~ i n c w n c ~ u ~ n c a b w r y o p e r a tpi nn gu u n ahwid be helplul.The chart ir In “an d i w accordingto nwldMwIlar. FLOW RATE IN OUNCES PER MINUTE kb ,I i "- Air Nozzle Selection AIR NOZZLES Siphon typo air nozzlas u n be used under fluid pressure wndllions bul prossun *pr air n o m unnot k made t0 dPhon. A spray gun nunuf.cturar'8 norria c h l r l l oHar nunmrous comblnatlona 01 air and Wid nozzles. Ju8118 in me wlactlon 01 a fluid nozzle, discuaaad in an earlier brua. ma uiedion 01 an air nozzle can also k confuaing. e Siphon lype air noztlaa are uaed mostly where amall quantttiea of paint are used lor normal aprayingonly. Decorallve work auch as veiling. apatler and normal high production apraylngmust be done wllh pressura type nozzles. An air no?zel. Of courae. is that device which break8 UP the solid column 01 paint exiling from me fluid nozTle Into a finely alomizad and wall delined ahapad p . t t m . The dagrw 01 slomlution and dimanlion 01 lha p.tIWII are related 10 air noule I y w and lo impoaad air pmaura. charta will also serve aa 8 guide 10 what types 01 air no~Ie.8aragenarillyuued~ilhmcvarioustypeaol coatinp materials. il should be noled that internal mix nozzles are 0 The For air atomizing spray guns them are two typrr of air recommended lor very alow drying paintr only nozzles usad. wllhvarialionrin bolhtypo~.Thase tw01yp.a are termed 'internal mix. and 'external mix' air nozzles. Tho external mix type la the moa1 commonly uaed: however, the inlernal mix is jual as important. Tho Charta indiuta mare each lype is appliubla. The menulec~urer'snozzle and needla charta should k your guide and will furniah Wch Intormallon as follows: e A series ot eir nozzlaa that will physiufly In o w a given wriea 01 fluid noaka. A manuladwar may have lhrw or lour physically dIHaran1fluid noalaa and M.ralon special air nculas for U c h or( Wad. 0 Tho Cham Wlll lndiula wtmther M. alr IWZZh h presauraor aiphontypeand OlanaxlarnaIorinteriuI miX1ypo.A prassuratype air nozzla. olenharan exlam1 or 1nt.rrul mix type. isonathatrequireathe p ~ i n ~ t o k l e d ~ o m r w r a y g u n under praaaure provided b y a preuurized vassal or e pump. A aiphon lypc nozzle. exlarnal m u only, k daaignad IO u u a e a vacuum lo be lormad on !ha fluid n m and merelore u u a e the paint to r i up~lromavesaalaltachad 10 the apray gun. Some charla will provide a column lhal Indicates !he maximumwidth of fen pattern that u n be expected at some specific diatanca hom me work 0 . fliully. me chart will normaliy have three columns devoted 10 air consumplion. Thaw are very importan1as mey raiate IO me sha 01 the comprasaor rewired. Nozzle conaumflion of air ia usually reted d 30 psi, 50 psi. and 70 pai. ThB higher ma Dreaaura ma greater lha amounl of air. lhla .mount b 1.rm.d cubic I n 1per minula (clrn).ila n be a6aum.d ma1 s compreuor will dallver k l w w n 3 and 5 ctm. Theralora. Il an air nozzle thn-8 ratad at 10 cfm and 70 psi were chosen, a ~ o o compressor d ot no iers lhan two horwpowar would k nMdOd. R u n be raid mal the higher me ctm rating of an air nozzle. me more volume 01 fluid per minula u n k atomized. In this win,~lollowslh.tIhalowcknno~lerun beowraledwilh small compraaaon by virtue 01 their having law orifice holaa. Those nozzlea with many orifices I r e high air uaera and must k u u d wllh large u ~ c t t compreuors. y SIDE PORT 1. Annular rinp around the fluid nouie tip. 2. Containment holes. 3. Wings. horns or arm. NEEDLEVAWE 2 STEM 4. Side-port holes. 5. Anpular converpinp holes. 33 INLET . AIR ATOMIZING NOZZLE 8 N E E D L E SELECTION VeilinglDistressing There are three basic components to consider when selectmg the proper nozzle and needle set-up lor y o u gun: ( 1 ) the air nozzle. (2) the nuid nozzle. and (3) the nuid needle valve assembly. AIR NOZZLES are 01 the following types: External Mix Nozzles may be siphon or pressure fed. They are the mosl commonly used and produce me finest finishes. Exlernal mix nozzles dim3 air into the Ruid after it has leh the gun to accomplish atomization. Spiral Needle Valve A u " core Special Efled Nozzles are generally 01 internal mix tyDe. They use vary closely regulated. low lluid and air pressures. These are usee lor such effects as: veiling, spatter, and distressing. They interchange with standard noxles on Bin& production guns. Reler to following charts. FLUID NOPLES perform these lunctions: (a) meter the fluid volume by the orifice size, (b)direct me fluid into the air stream. (e) form a sea1lor the lluid needle lor shut olf and. (d) align tha air nozzle lor attachmenl to the gun. External Mix FLUID NEEDLE VALVE ASSEMBLIES are used to shut on fluid now and 10 meter the nuid to some degree Needle adjustment is provided on some guns to compensate for weer. Air Nouls External Mix-Siphon Fed ere B e d to siphon mateital trom a gun cup. Primarily used when small wlumas 01 low viscosity paint are required. Designated ty me loners 'SE" in the "TYPE" column d me foliowhg cham. Extenul Mix-P~rrunkd require pressure to supply me paint to Me gun. uwally a pmssure cup. pressure lank. or a pump. Used when large quantities d fluid am sprayed in production won. This nozzle type has a l a r g e r a w 01 selection lor fluid Row and does no( limit paint container size. Designated by the ldtleK 'PE" in the WPE: column of the lollnving cham. Nozzleand Needle Selection Air Nozzle H . . Reler to the 'Tvue of Fiui to be Srmved" columns lor exemph of n&e types.ioiiowee by iecommenoed nozzle setups m me -nuid x Air Nozzles wiJmn (2) Determine tha method of atomizalion. I e siphon or pressum Ibbdaxternal or internal mix (3)Select air n o d e with an alr demand within the output limit 01your compnrror. Remember to conrlder lhe air rwqulnmnt of omer equipment also rupplkd by the compnrror. (4) Internal mix air nozzles are 01 nvo primary malerials '100 senes are 01 tungsten caroioe and 200 series a n 01 nnnlloy Internal Mix Fluid Nozzle (1) Choose me fluid nozzld by determining the apDiarton speed you want and the approximate flu0 VISCOSII~ The tancr Me speed or the heavlcr the Iuid Ihe l a r y none onhce sue snould be Reter lo page 19 for an orifice sue reterenm chan (2) Match the fluid nozzle to Ihc oesired air nozzle Der the chan Needle Valves 8ase Fluid "Z!+ Fluid Nozzles Internal Mix Nozzles must be pressure led either with pressure cup. Pressure tank, or pump. The spray pattern is determined by the nozzle shape and cannot be changed. These are recommended lor maintenance spraying where fine firujhes am not required. internal mix ryuzles cause the air and A u d (0 be mred inside the nozzle. therefore are no1 recommendedtor fast dry malerials such as lacquers. Less lcg is reahed man with external mix nozzles. Designatedby the lelters 'PI" m the "TYPE mlumn 01 the following d a m . (3)SeW the material 01 wnslruction: Standard lluid nozzles are hardened steel. Add "SSto nozzle number if stainless steel is desired or " V T iftungsten carbide is desired. Reler to Fluid Nozzle Reference Fluld Nweie Vatve ( 1 ) Select the proper needle size number per the cham (2) I1needle number is no1 shown in the than wtumn. nozzle setup listed lhereto is not applicable lor that gun 34 Air Atomizing Nozzle Extensions Nozzle Extensionsdesigned to reach oul-of-*way places. Models for general use and for specific applications. 7A Ex(efn8lu 6.9,12,15.16,24 "naMIX 30.36.48.w.72.84 s!d. bloflul of lnWnul MIX 17~ sc + a 30' 6.9.12.15.18.24 30.36.48.W 7 2 . 8 4 6.9,12,15.18.24 30.36,48. 80.72.84 2% Sld.ExtUWof lnleml Mix 6.9.12.15.18.24 30. 36.48. w. 72. 84 1Y. 1" of InumrlMix 30.36.48.w.72.84 6.9.12.15.18.24 EnemI of 6.9.12.15.18.24 lntemlMIX 30.36.48.60.72, 84 34 Circular (360') 6.9.12.15.18.24 30.36.48. MI. 72.84 38 Cimlar ( W ) 9.12,15.18.21,27 33.39.51.63.75.87 1% ERX tarrml u h"lMu I I High Volume Low Pressure - HVLP HIGH VOLUME LOW PRESSURE SPRAYING Hw (high volume low pressure) spraying has quickly become the biggest trend in Anishing today. uses Baseline Tnruter Eltlci.ny approximately the same volume ofair p1 a conventional spray p.m. but at lower p r e y u r e ~to atomize the fluid. Reducing air pressure at the n o a l e reduces the velocity of the air stream and atomized fluid. This in tun has a positive effect by reducing the “bounce back’ of material from the surface being coated. The resulting spray is high in m f e r efetiency. wmss”ic REASON FOR HVLP World-wide concern over air quality and hazardous emissions has generated an enormous interest in HVLP spray eqwpmenr Assuming a leading role in mandating more environmentally sound painting operations,the cplifomia South Coast Air Quality Management Disaict (SCAQMD) has spccised HvLpspray guns as one ofonlytwo types of spray equipment approved for w within im disuict (the Los Angeles bppin). Similar legislation has been adopted, or is now under consideration. in many other i n d u u i a k e d are= thmughout the United States.As these areas i n d u c e their own rules, the EPA will require them to be as rrrin. or stricter, as the California legislation. High -fer eficient equipment may ultimately be a requirement of operaring in the finishing industry. Recognuing that the essential channerktic of HVLP is low air velocity created by low atomidng prrssum. the SCAQMD d e h e s HVLP as any device that atomizes paint with an operaring pressure at the air noale between 0.1 and 10 B I G . Ovenpray IS a mqor problem for many compmes m the finuhing industry Vutuaily all spray fituslung opemom can be advenely affected by overspray and ttus can result m costly mamtenance and downume operators of painting equipment are ais0 directly afrected by overspray. The fumes emitted into the air can be hazardous to their health. Visibility in the spraying area is also reduced by fumes and this contributes to mistakes and low productivity. TRANSFER EFflClENCY A higher uansfer efeciency improves the quality of the work place by reducing unnecessary pollution and it improves the quality of products by providing an excellent finish. w .. -..- - . . . . . . . . . . . . . . . . . . . . . w.-m- ...... .... ..-.-.. I - . I ” AirEh”i2 Air-AuDwUrbs . I _ _ . . . . . . - .... .-. HVLP spraying can be two to three times as efscient as conventional air spray which can cut material costs and waste. Conventional air spray usually proves to be 30%to 40% eiecient This means that over two gallons of paint ye w u t e d due to overspray. for every three gallons that ye sprayed. With H” spraying at an efetiency rate of 6j% to Bw4 p1 Ilde as one pint ofpaint would be wasted for every gallon sprayed. Another major problem for finishers u waste dsposal. By uaing m.HVLPsystem. with its high -fer emciency, wasti disposal costs are lowered. Productivity will likely increase with an HVLP system became fewer passes are needed to build up the same Blm chicheu since more material is applied with each pa!w due to HvLp’s high transfer efedency. HVLP vs. ELECTROSTATIC When comparing HVLP and electrostatic spraying you must consider the part that is to be sprayed. Unlike electrostatic. HVLP works equally as well with nonconductivepans like plastics and Woad as it d m with me@ substrates. No special prrp.ndon o r ofthaaprrr b to MIR condnuioto mrmdmea3llwrdn, of the put is also a faaorrhen mMng chb e o "U the pan is @e a n U o r h t an Hvtp system Mneet or exceed the rrpruler emaeneg of most clacmaudc spny systcmr On the olhcr hand Kthe pur hm a lot ofCYUP &idshapes or open rp.ca.U e bicycle m a or chain Unk fences.electmwic syxtem wiU provide be= mansfer emaency than an HVLP -em due to the 5mp' eUecr An HVLP system eliminua the pmblem of Fanday cage effm which a n p-t eleetmstPdc rysturu from pencaving into maredMIL operatan tend to accept an HVLP ryncm mote readily than an 'c m m for severdl rew~nr.The main "on for iu quick acceptance is there is no high voltage 'stignu" associated with KvLp like there L somerimes connecccd to eleemrrun'c handguns. Another major mason for high accepunce for an HVLP system is that it can be used with waterbawd coatinp without the need to Isolate marenal supply wk, or the c i r c u k hg system from the electncai muna HVLP uw onen berm dpke orienrarion control when applying metdlics. u The fact that an HVLP ~m h pacer adapubiliry and it is genenlly leu ucpendve than an e l e c t " ' system rlso makes it v u p popular with Enishing Opvnrlons on a tight budger One advYluge of an elecmmrticsyncm ptprrxnf may lie in iu ability to hand&tugh solid rmfcripI?Iand pmvide higher flow r&m to keep up mth dcmMdfag pmducrion SChcdulU HVLP VS. AIRLESS AND AIR-ASSISTEDAIRLESS Spray from high prusure. n o n - e l e " ' C y n * r u c h P 1 airless or air-8sist.d airless,we gm.uy in ita owfu edicienrl fromrppUcadon IO apptieadoa 'hperformance of each apptierdon muR be documentad on a cmc by-case basis because many MInot meet the mmi" 65% udnsfer emaency requiremenu For thir won airI ~ S S a d =-P i r ls ~ystem hpvc not ka univerw l l y accepted u complying with mini" murex eficiency sunduds u dnucd by gownmmnlwenaea On the other hm4 the 'soft spray' &om an H M p gun will provide a genenlly higher Udnsfer etliaency with a k n e r overall tinrrh. Recently. a study wu made of print droplet sizes. Three methods of atomization,working u peak ef8ciennes. were meamred for droplet sizes. Compressed air. including HVLP.produced droplets rangingin size from less than 1 micron to 150 microny. ~ - u s i m nW l w produced droplets ranging in &e I "IWZtYl microns. Airless produced drupleu ranging in size from IO0403 microny. Needless IO say, the method of aromirvion chosen will g'eaUy effectthe dnish For this reason airless spray untplly is not considered the Ultirna~ pmens for applying a high grade tlnirh masand air-&ed airless aUow for an haeased working speed due to theu higher flow We. bur lack the Ene &rish cPprbilitiia of HvLp spraying. The m f e r elllciency and llnish quality of M pirltss and air-assistedairless system m a y be improved by udliring a heated m a t e d supply system -- Whenit coma to selecting M HVLPswm that is bet for a parfieulprjob the factontha! affect thir decision are the that should inauence the seleedon of any W h - insSome ofthe most important components in rhir decision umking p m c a are the RVLP system' uomizPrion quality, mbabllity. the mpplien technical support and the availabiIity hxrvlce and spare par?sfrom the supplier. Among &me, a m e o n L.r probably the most c r u d element @the system Remember.Property selected air caps and h i d t&nare needed IO aswe proper atomization with an W g r m W e m c y p e r of air soare available aith WVLP rhnt will provide a wide range of delivery volumes andprrmvaThexsoUnaBnbecenmlized,xrving multiple guns. or can be dedicated to sindngltgun w. -nu Genenlly,maximum~rrmycisben,buttheairprmurr measured at the n o d e should be h r e d to 10 PSI, It's volume, ~t pres" rhat atomizes the coarink RVLP sysuem hm a d e t y Of%Y¶ in which material h supplied to the gun Among these are siphon cups. pressure wks pumps and other " m t i o n a l fluid supply systems. n o w n!quiremenu are Usurll~lower with HvLp than with for simiiar rppticatioru because of the air spray higher " f e r efEaCnCY. As a "UIt muller onfice fluid n~~~~esareuntpllychmen TURBINE va. AIR RESfRlCfED HVLP'SYSTEMS The moa imponam decision h e n choosing an HYLP JYStan is be*seen the two U C air supply designs. One wes a mrbine generator tD m d e air flow and the other conVCN GOPSIshop air 10 10 PSI air Uthe gun n o d e . Both mnh& have their own advMuges and limirariorui. ADVANTAGES A N D U M l l A T l O N S OF TURBINE HVLP SYSTEMS When luing the turbine a V P W YOU get W a r ponu not paprible when YOU'R Cotltlecrcd to shop hdcy pLT tines. NO^ d naushmg done III a s p n y booth wth an unlirmted supply Of COmPrrued w. m g shop UT sources a h may not be able to oRer suBlaent v o h w for an Hvtp system. ADVANTAGES AND UMITATIONS OF W AIR RESTRICTED AND AIR CONVERSION SYSTEMS A Lm ~ a dHVLP spnY gunt are desiped to m a aw pressure within the gun body. Ihe d t u a low p m s w &charge of UI unpmgurg into the d u d sueam mulung III an " u e d spmy pycem wlth Im rurbulence and w m e AU " n e d models Mthe most popular HVLP guns in we. (See R p . 14). U the UT m a k e m e m and Its ater are well designed and mrunurned. turbine pu generaton pmvlde nkuvely dean. otl-he and dry UT. &r convenlon wrs take hgh p~essurecompressed w a n d mmct its flow so low PFessure u u delivered IO the spray gun. As with aar mtncted HVLP systems. the volume ofau Irmrunmed. Mcdon from a nubine wt can generate enough heat to p m d e m o d e m m temperdturm. but the t e m p e r " of the au depends on the d e w of the nubine, its distance from the gun and the m h g value of the m conduL T~ISf r i m o d heat ISnot always conaollable however. One must also consider the inconveruence of large and bulky ax hoses connccang the m i n e to the spray gun 7he nvo msJor drawbacks ofmost turbme synenw are that they offer uuufEclent pressure to a t o m some hgh mmity or hgh solid matenals properly. Turbma EM also be m t e n a n c e prone. The use of air restricted and air convenion uniu enable you to conml imporlant variables. such as hear and pres' sure, which aaect application p e r f o m e ~ . Air resuicted and air conversion units can be outRtted with optional air heaters which pmvide the operator t o u l conm1over the air temperature. The heat can be varied or it can be turned off completely. An HVLP system which uses exbthg shop air always d o m the user to add conmlled heated air which may improve tack or dssh m e . which reduces ~ l land s sags. Many tests conEm rhnc atomization of some matine from a turbine unit can be d e q u a r e with lerr than 10 PSI. Uncontrolled heaced air may upsel the balanced chenusuy of the material and interfere with the proper leveling of the 6Jm M e n you reduce the coating material with solvents m y of its expected qualities like coverage or hiding wiu be lost Doing so may also violate local air quality maictions. With turbines that generate less than 4 PSI of pressure Enish quality may be greatly affected. The p m ~ u r eof the air matso be regulated with air m a i d and air convemion units.They can be adjusired to deliver pressures mging from several pounds to 10 PSI or more. The friction that results from the w of a turbiie CM atso be the source of serious maintenance problems. Many tur. bines are not designed for continuous sprayylg, therefore. the higher the t e m p e m gets. the higher the friction gets. and higher friction m e w shon bearing life. Because of the possibility for increased temperuurrs. mon turbines that are to be used inside a spray booth must be of a m t l y multi-stage explosion-proof design. The inadequacies of air restricted and air conversion mts pnmyily revolve around its relationship with the air sup ply. Most H" spray Buns will require a 3 H.P.compressor or larger per gun t o satisfy the CFM demand of the air nozzles. Edsting shop airlines and flexible hose must be capable of delivering a sufecient volume of clean. dry,oil-free air in order for the spray gun to work emciendy. Remember, most turbine IWnUtacturen supply performance data independent of 'load" use. For example. a unit rated at 7 PSI may only deliver 3 PSI under load. Ask your vendor to d e m o n s m e Pressure at the gun n o d e of any system you are interested in. U the existing system is adequate for conventional air spray syscems. it will sufRce for an WLP system as well. It is ako recommended chat HVLP gum w a minimum of 5/16' ID. air hose. 38 OCMionrl nuintnunce pmcedura and ddiclorul esuip menrnuy be rrquuedto UNR r h u t h e sirir dan. dry and oil-free.If conrnminued air d o u d o r thm@ the s p tem it could ruin the appLia(l0n. If the e m sir supply system is pmpedy mainminedfor conventionrl air spray Mhing, however, these same procedures and equipment d ls d c e for an XVLP syrr~m. Roblems WDClofed ' with either type ofair supply method, turbine units or air rrrroined units are manageable. An educated buyer should be aware of potenrial pitinlL ofany given approach and look for the solution that will offer the fewest o v M n Ilmitations. HVLP IS EASY TO USE No specid haining is required to use an m e" Operyors will m n lean the subtle difference between spnying with an HVLP synem and spraying with a m v e n tiond air m e m XVLP, like mnvendond spraying,is available in siphon, @miryand presswe feed spaem* As with conventional air atomization, operatOK should learn to use the lowest p ~ thatwis necessuy to produce a SaIiSfactOry spray ppncrn hother difference is in openuor technique. 'Ihe gun should be held closer to the surface of the work piece when using HVLP equipment because ofthe slower forward weed of the atomized particles. Greater dimnee from the p M results in euyI.dyc dryspny and lackof tllm A good rulcof-thumb is to hold the gun 6'to 8 ' b m the PM that is to be sprayed M y llrs~ time HVLP w m get the impression chu BVLP spraying b slower than convendondair spny. Genually, this b not the cpx. However, because the dlm thkhm with HVLP is often greater than air spray rynemr.fewer total passes are needed for the desired build Sometimes HVLP appticadon might be slower, but chis is g e n d y due to operaton who prefer a h e r dnish aver speed of npplicodor~M e n who require fvrcr applicafioru HCZP compliance and higher -fer emdency m y want to examine HVLP air-assisted airless. See Binbs TD113 for funher d e u i t . Figuru 1-6 show typical air resuicted HVLP spray synuns. In conclusion. HVLP spraying has become a viable p r o e m in the Enishing industry, so. like any new approach, it can present many pitfalls for the unwary user. M o n of these IWS can be avoided with a thorough understanding of the process. The end result is a spray appticadon p m a s that will quickly pay for itself and lead to a better environment. due to the fact that HVLP system create less waste. HVLP should not be considered as the cure for all Bnuhing problems. Remember. all methods of a m e o n will have their advantages and limitations.This include the process h o m as HVLP. 39 HVLP OPERATORS CHECKLIST 1. Is your compressed air MlDcc large enough? A typical air Rspicted HVLP spny gun rquiruat lerrr a 3HP c o m p m r . 2. whrr is the lengfhand inside dipmctv o.) dthe air hose? It Is " m e n d e d that the s h o n a length and largest LD.air hose that is pracricd for thejob be used 5/16"LD.minimum air hwe is recammendcd 3.Are you using quick disconnects on yournirhau? II your air mppiy s ) "Is borderhe, stpy away tram rhea Although these items are a convenience,they also ~~~unw~tedp-drop3whichmaymbbuable AiIp- 1.Have you seleetcd the pmper .irand fluid d e ? Your csuipment SllpPliv should be able m give pmper rrcommendrdom.Remunberasyourllownta incrrw.youratomizacioncluali(ymrydeaeme. Experiment with a v a r i e ~ of n d e c o m b ~ o n i to 6nd the combindon that works kn 5. Checkyouratoznizationairp-alth.nairnde Mgauge assembly. 'Ibis should tell you the pctrul .(omizadon air pnrnve being used as well p1 if you meet anyspeallc airpuPUry ngullnom (Ste F& ;3 AIR PRESSURE Atonunng pressurr must be set to pllow lor the dmp m au premtre between the regulator and the spray gun with 60 PSI applied at air supply: Only41 PSI h 54 PSI at gun inlet 25fsetof 25 feet of 5/16' I.D. hcse has a drop of only 5 PSI. For 1/4' I.D. & *aamx.bPSI at gun inkt hose cswesadrop of 16 PSI batween the au supply and the gun. ths reason we mommend the use of 5/16' h e . NOT RECOMMENDED) (RECOMMENDED1 Cross section view showing companson of mlde nose diameters (actualme). 40 5/16' OPERATOR TECHNIOUES The 8114conridemion for a pruperly o p e d n g HVLP gun h operacar technique Mthoush no apecui ttduuques UT requtnd a m i e w of m e common faulty spny patterns and spray technique is u followa: TYPICAL FAULpl AIR NOZZLE SPRAY PAITERNS Pattem L Cause 1. Dned pant in one of Me side port holes of ar nozzle. Correction 1. Dissolve paint in side port hole with thinner; do not probe in any of the holes with a tool harder than brass. 3. Fluid pressure too low. 3. Increase fluid sup~ly. 1. Air pressure too low. 2. Excessive fluid velocity or loo much fluid. 1. Increase air pressure. 2. Use smaller fluid nozzle orifice, lower fluid pressure. 1. Air enlenng Me fluid supply could be caused by: a. Loose fluid nozzle. or not seating properly due to dirt. b. Loose or missing packing nut or dried fluid packing. c. fluid connection loose. I SPITTING SPRAY TECHNIQUE The Bnt requirement for a good resultant f h h b the prop er handling of the gun. The gun should be held perpendicular to the surface being covered. and mmedpuallel with i t The m k e should be Raned before the uigger is pulled. and the trigger should be released before the m a k e is ended. This grves ac-e m n w l of the gun and material. t 6bllhdm %ti c- N -9Ww v-F- a.Tighten fluid nozzle. or clean fluid nozzle seat area. b. Tighten packing nut, or replace missing or dried fluid packing. c. TigMen all fluid supply connections leading to spray gun. The distance between gun and surface should be 6 to I? inches depending on mated and atomizingpressure. The material deposited should always be wen and weL k p each m k e over the preceding moke to obtain a uniform Bnrsh. GENERAL SPRAY INSTRUCTIONS To reduce overspray and ob"umefUaency, d w a p spray mthlowest possible flulcvlv p ~ s u r thu e produces M . m p u b l e S P ~ Ypaaem - Excanve v o m r n n g air PrruUra can Increase ovenpray, reduce " f e r eficiency, and w ~ t hsome maten&. m u t t in poor &ush W r y f"dry spray. Atormnng a r presshould not exceed 10 PSL For best d e ~3 U, 6 PSI 8tud pressure. Higher than 6 PSI fluid Pbe reguued for heavy Wed m e r u i s . Low Uiud PW pmduce a narrower than normal spray paEtcm. Generally use 3035 PSI PV at gun lniet Unusually heavy, difecult to a t o m may rrqutre up to 50 PSI ~ at II gun d e r For bmn mfflsimnsy, 0l.c spray and n b o u n d should h l l t o w u d uripaintmd surh e n (abovm). Alr movmmmt ovmr t h m p m d u n and uny. o1.r d t h m d - s p n y and n b o u n d 8hould ba toward tha unpaintmd surlacm (right). FINISHING FINE TUNING YOUR HVLP SYSTEM Some tips to achieve optimum quality from an HVLP spray system Stan nroke Puli lnpper I I t4 - Coaling will be Ihghl a1 lh16 P o m lngger moke . I I I// I A GENUINEc o n c e r n over the environment is changing the spray finishing of wood producrs. High-volume, low-pressure atomization has emerged as t h e most widely accepted method of spray finishing in furniture plants. I n fact, HVLP and electrosratics are the only accepted methods of spray finishing in Southem California today and possibly in your area tomorrow. Most finishers who have switched to HVLP report they are pleased with its overall performance. Finish quality generally meets or even exceeds expectations. As with any method of spray finishing. however. there can be problem. Some of the problems associated with HVLP a r e n ' t t h e result of equipment failure, but rather maapplication and operator error. With some fine tuning of your HVLP system. this gap between success and - Release End of Coaling w~llbe heavy at fhiS pOm1 BY JERRY P. HUND I A good finish begins with proper handling of the aprey gun. Hold the gun perpondiculer to thb sutlsce being covered. end move it parallel with the sutlece. Holding chs gun 6 to 12 inchea from the surfeem, NR tho moke before the trigger la pulled. end nleese it before the stroke ia mnded. failure could be reduced. HOWdo you determine if your HVLP system is properly fine tuned? First. examine t h e energy source or air supply. If you're using a turbine. is it adequate in sire to handle the number of spray guns and does i t have enough pressure to atom. ire the coating! Do your math If you're using airrestricted type HVLP guns, examine every component of the compresxd an r up ply svsiem. Determine the air con. sumption of the spray gun in terms of air pressure (psi) as well as air volume (cfm.) These fipres are usually available from equipment supplier data sheers. Never expect the HVLP gun to periorm properly when its air requirements exceed the availability. A typical H\'LP gun m a y q u i r e up to ZL! cfm t0 perform FrOperl)'. Becaw rhe average elecmcally dnven compressor provider about 4 cfm per horsepower, simple anth-imetic tells you 3 5 h p compreso: is required. A simple test to deter- I I CHECK YOUR HVLP SYSTEM If the raulrs from YOUI HVLP spny system aren't quite 1 what you wantI here are some areas to check. Make sure air supply is adeqrute for your needs HVLP guns require up to 20 cfm. Are bath air and fluid pressure at proper Icvck? Air preuure l a than 10 psi. fluid pressure between 3 and 6 psi. Check the air hose. It should be at least 5/16.inch inside diameter. and as shon as pouible. Examine spray gun nodes to re+ if they've been properly selected and maintained. Review operator techniques. For b n t mtflcimncy. o v e r spray and rebound should fall toward unpaintmd s u r tmcms Iebovel. Air movement ovmr t h m product and uryover of the off-spray and n b o u n d should be toward thm unpeintmd surtmcm (right). mine if t h e H V L P g u n has enough air is to slowly spray across a flat surface such as a cardboard box. If the spray pattem gradually decreases in size. the air v o l u m e is inadequate. If excessive orange peel is evident. the air pressure is too low. Next, e x a m i n e h o w the air gets to the s p a y gun. When using a flexible rubber hose. it5 highly recommended that i t be the shortest length and largest inside diameter practical for the job. For air-resmcted HVLP guns. the minimum inside diameter air hose should be 5/16 inch. Stay away from 1/4-inch diameter hose. k a w e air pressure drops as it flows through a how. it's wise to keep hose lengths that are just long enough for the job. Stay away from quick. disconnect fittings if the air supply is minimal. These devices cause pressure drop and may lead to frntsh problems. If ywr atr , s u p ~ISl a~ d q t ~however, they aren't a problem Watch your pressure Don't overlook t h e pressure dmp through the spray gun inelf. Although s o m e HVLP guns a r e designed to cause a pres sure restriction within the gun body, for the gun to perform properly it's preferable to have a n a d e q u a t e supply of air available as it enten the spray gun. Newer turbine H V L P spray guns a r e a v a i l a b l e t h a t have almost n o pressure drop as air travels through the gun handle. As a result. the spray gunb air nozzle should perform at peak efficiency. Air nozzle test gauges are a convenient way to accurately monitor actual nozzle prwurcs. They are also used to determine complmce with local airquality codes by irpectors. Spray gun nozzles also should be examined to determine if they h a v e been selected and maintained properly. Consult the equipment supplier's data sheers to determine proper fluid nocle orifice size and air nozzle selec. cion. Experiment with a variety of nozzle combin a t i o n s to find w h i c h components work best for your panicukr coating. Generally, expect finish quality to decrease as flow r a t a increase. Common sense tells us t h a t with a given amount of energy available. t h e more fluid available, the larger t h e droplet. T h e less fluid available. t h e smaller the droplet. Thus. if higher mil thickness and finish quality are desired. spray two t h i n c o a t s i n s t e a d of o n e heavy coat. O n e more tip The final consideration for a properly tuned HVLP gun is operator technique. Although n o special techniques a r e required. a review of some of the basics can always improve spray application eiiiciencl: To reduce overspray, always spray w i t h the lowest possible fluid and air prmure that produces an acceptable pattem. L t c u ~ i v eatomiring air PrCSSUrCS c a n increase ovenpray. Atomiiing air pressures shouldn't e x cetd 10 psi. For bcst results we 3 to 6 psi fluid pressure. Hold the gun perpcndicular t o t h e surface being covered and move it parallel with the surface of the workpiece. Stan the stroke before t h e trigger. is pulled: release the trigger before the stroke is ended. T h e gun should be 6 to 12 inches from the sur. fdce. Lap each stroke over the preceding rcroke for a uniform fiiuh. * Hose and Fittings 1. PRESSURE DROP A The most important mnsideration one must give to the p r o m selection of hoses rad fitting8 k the premue dmp. The realization of what prexue drop k rad how It effects the equipment$ oper. ation must he understood. In order to understand p m r e dmp one must have a hasic knowledge of what C.F.M. (cubic feet per minute) and p.hL (pounds p e ~s q w e inch) uu C.F.M. k defied as a given volume rir that nons past a given point in one minutes time, and P.LL is the m o u n t of force pushing the a b l e foot of alr through the hose or t w L The m o u n t of ah that a tool c o m m a will re, main conrtrnt for a given rt of conditions. The prrsrure rill always drop whenma the tool L W e d on rad, when the air begins to now through the hose. The prraurr drop will vary in relation to the djurtment nude on the tooL The n m e pressure loss o m when we rpert of moving a fluid through a hose. Therefore one must rlso mDlrder p"1066 for the pmpersefedion of nuid hoaa m d fittings P "drop CMIlOt be elirninlted beclue it wffl always be present. The only t h i i one can do k remgnize the u u a a then " i i the effects by considering the following: 1. Frictional redstance between the fluid arid the walls of the hose. 2. Frictional lo5 as the fluid hu to flow o v a itself (internal resistsnn or shear). ThL k M u s e the nuid moves kan through the center of the hose m d slower against the walk. 3. The restriction of flow due to the change of d h c t i o n the air or fluid must take. 4. The volume of air cr fluid the hose must euy in a given period of time. This h determined by the amount of hick pin the +em. 5. The aehul weight of the rir or nuid h e i i a u i e d in the hose. For b e e , the elevation must be recounted for at the approximatexate of .5 p s i . per foot of Ut hred on water. 6. Rcstridion through asx~chtedit" Qch us. hone connections, adapters, nippleq valve& N t m and air and fluid controls that are being umd in the system 6. The condition which effeck the p m 1 0 s in the selection of the h a e ue: t The h i d e dkmeter or oosseetional uea of the hose hrr the pertest effect.(c.g.when a 117. inch ID.hose k used indead of a 114 inch 1.D. hose, the prermre ion in the half inch hose wlll he almost 20 times lea than the 114 inch hose for the aw conditions). \ \. I I 2. Ar the length of the b e increws the p ~ n u r e dmp inThis dmp h pmportiond through out the total length of the hose. 3. The conditions of the surface of the inner tube will greatly innuence the p m drop; a rough tube CUI cause u much as L 50% haease In prarure drop. I. 7 , kctumr lltenture for amount& Thir factor determine6 the h i d e d h e t e r of the hose raluw NOTE Remember. the greater the volume (CFM) of air that must p a s through the hose in a given time the greater the presnv:. drrn will be. Below k a list of Y)he typical ail u ~ . ~ : l ~ - d equipment and theapproxlmtc C F,!,f. r y i + e d air at 100 p.ai II. HOSE CONSTRUCTION: A The basic wmtmction of most ah and fluid hoses &e comprised of tbe following pa%: ... ... .. .. .. .. . . .. ;:, . . . .... .. ..... ... .. . .. . . . .. .. .. .. .. .. .. . . . .. AIr Motor bpiutor t v p l . . ., C'h, &rlm Pump lone G.P.M.1 .. , . , 6.10 CFM Airlm Pump Imo G.P.M.1 , . 20.50 CFM Airlm Pump l t h m G.P.M.1 , , 3040 CFM Duttinppun Blow P n l . . 3 5 CFM Low promura Pump lJic+n l ~ i i l l i i . 4.16 CFM Low prP1ura Pump lnudium m n r u l c l 10.22 CFM Low p e w r e Pump lhow mnnislrl. 2340 CFM R m u r a u n k bnvrizel. , 1 CFM sprsv gun Ihonmoyw w ~ d . .2-6 CFM a r 8 V QUn (woduction @Xl." mix1 . . . 1015 CFM Soraiiun i k d u n m n t v p lmaMl mix1 5-10 CFM Spav gun I u n d a c M l q imerrul mml 1bx) CFM 1. TUBE., The only put In contact with the coating nutaid. It Is urefuuy selected to redst the mlvent action of the coating under application temperaturesand pressure. 2 CARCASS.. One or more L pz of high tendle fabric or mew braid bondled to the tube and jacketquired to provide satisfactorily high working and designed to provide d m u m rlz.tEty. 3. JACKET.. Tbe protective outer wvercbosen to resid damage from abrasion and wur, o h and cbemiak and atmospheric exposure. . III.AIR HOSE CONSIOERATION A. When selecting an air hose consider the following points: t Tbe w h m e of air h t tbc bole must any; tbis m a y be d e t e r m i d by t o W i the air conrumption CFM) of dl the ab tools supplied by the we at one time. See the m u - . . 2 Tbe second factor In determining the inside uired Is the toul length. This diameter length c b o 3 be determined by measuring the distdnn between the ln ut point of the au and tbe point of ndt If pong distances are en. wunted, the reduction of the inside diameter in Wes will bel d u c e pressure Loa and Iowa the cost o! the bose over the entire length or by using a wipend. Tbe charts below indicate the pressurrs dmp in boss for tbe foUowIng condnionr: 6 AIR HOSE SELECTION GUIDE brd on R . a u n Drop At 90 PSI Input S / W ' I.D. I l o n - H.P. Rmaui" 81.1311 I a 6108HP 81012np Y - 8 - 11.12 12-13 13.14 14-15 1516 le-18 iex) 2025 3.0 3.5 4.0 8.0 6.3 7.4 @.3 9.5 Y 8 c - I P I " I 2.5 i i Y 2.0 4106HP 6108 HP - - '5.0 .O 6.0 7.0 8.0 3.0 3.5 4.0 6.0 6.0 7.1 82 10.0 - + 10.0 10.0 1.4 1.6 1.8 2.0 2.6 3.2 4.0 4.8 6.0 8.2 5.1 6.6 10.1 10.6 - - 1 9.0 - I 3. The total kngth of the fluld how from the point of dlcharge is another factor in deter. minlng the h i d e diameter required for the hose. To help In determining this, the following pressure l o r chut is submitted for approxi. mating this demension NOTE: For dud production rpny gun appliutlons, 5/16 1.D. for a nuximumof50 ft. isthe recommended &e. For pump appllcatbns 318 I.D. should be used at a nuximum length 01 50 feet from the ah supply to the pump. 3. The third factor In rlecting an ab hose b the matems worklnn oresswe. The workine pressure of the hose &&id be selected according to the blghew amount of prexure the system is caw blc of machlm? 4. The forth factor In the election is the materlal used in the construction of the hose. This should be b a d on the MtUm of m y llqUMS that may be introduced into the alr hose, either intentionally or IS a result of equipment wear, such 16 catalysts to CUR a plastic coating or oil leaknee " from a comorewr. 5. The flexibility requirements should be determined by how many times the hose is bent or moved m d who will be holding the hose. For a m p i e , men or women rpny opentorh - E. Cost-Hose should not be based on initial cost but on the benefits one wIU receive over the e n t i life expectancy of the hOK. D. Basic Types of Air Hose Construction: 1. Non-oil Ipsistant-a general purpose air hose recommended for spny guns, pumps and pre& sure pots, where oil is not present in the air supply. 2 OU reslstantmcommcnded for Industrial use and to paint rpny applications where cntmined oil and u t d oU mntamilytion b quid. 3. N Ion m t n c k hose pmnrnently coiled nylon -eMce where it is desirable to have the lir hose ntmct to an unobtrusive loution 4. A h how with a static (noundine wire Samers h e oil resistant hose exceot it incorooralcs a copper groundine wire 1; tbe bnid. Used mainly to prevent the poxibiiity of fire due to static d i r c h q e m d puticululy belpful .in minimizing a finish failure commonly mfemd to IS mottiing. V. FLUID HOSE A. When selecting fluid hoses I.D., consider the following: 1. The uohmc gf material to be curied by the hose in a riven period of time. This may be determined by checking the volume of nuid required by the tool being used. 2. The uiscosity of the material should be measured by instruments or compared to the way some Nbslances move. For example: Ulsuid hiption AkOhol Very thin Thin mter K:sOS.?"c Medwm Motor 0 1 1 X 1 0 wmght SAE Medium H u v y M o r Oil nnw Cwn 011 V R y hUvy WlDSSCS Extra huvy cmtipar .2 1.w 10.00 1w.w I.m.w lo.m.w 1w.m.w b o l" Feet-4 r n Size of inside diameter required no. I.D. Of uud 1 Y 1.0. 11, I,D, 3/8 I,D. 318 I.D. T Y P ol Fluid U d Ddir.ry in FI ozMinuti 32 FI o z M 32 FI OZIM 32 FI ozlM 32 FI ozlM I1 I Water (21 DOP 111 Water 121 DOP Approrimmi R-ri Drop 3 prl 76 psi .5 mi 16 mi b a t 71OF. 131 SA€ 33 Welahl Oil mr mururld 81 63 wands in a f 4 Ford It must be remembered that if the hose has any bends in it or fittings, the p m u r e lonwill be grater. If the fluid viscosity is greater than water the pressure l o x will also be greater. if the vkosity is l e x then DOP the prermre ion will be less. Therefom, since most l i h t consistency paintshaveviswsities that fall between water and DOP. a 318 1.D. hose is recommended to minimize the pressure 1% When the vixosity is grater then DOP larger I.D. hose should be selected. The approximate m o u n t of material one can expect to find in wious sizes of hose lengths might be of some interest and are therefore listed below: we Of nou L-h ol ((OM 1N 1.0. 1N 1.0. I H I.D. 15 Fret 25 Feel 1W Feet 3/8 I.D. 3/8 I.D. 318 I.D. 15 Feel 25 Feet 100 Feci Comma in Gallons 05 D6 25 .on .14 .6 The amount of materiel necegvy to til! a hose is quite d l , therefore. when storing nuid hose it would be goad practice to keep the hose filed with a solient which will not attack the tube of the hose. Keeping the hose wet prevents matcrial from IiarJrning 111 r h c illsi-!c. brelking loow, and later plugging the nuid nozzle ,,r 11, Even though one may flush r)vt a how. a small amounl of residue can remain behind and cause problem- B. Considartion of the fluid how mratruetion: 1. Solwnt resirtoner. Not dl fluid b o s s ue able to rryd rU types of solvent and cheml& There fore. It is important to select the rIgt fluid hose for a c h application. Check the rmnutacturerr mlvent nrirwlce chut howtng the suitability of nriour b o s a to m i s t different chemiulr and solvent& As an ride in decting the p r o p fluid bow for the vuiour rolvents, one might consult the foUowing chut. I FLUID HOSE SERVICE AND SELECTION CHART TYPES OF FLUID HOSE AND TUBING ROOM TEMPERATURE SERVICE: CONTIN HEATED MATERIAL SERVICE: CONTIN TYPES OF SOLVENTS, THINNERS, AI kvdr IN.pmk.1 I I 0OO.O C k k . Rub. Zinc Rich Stliconn iRVlCE iRVlCE Nvlon High Prwwi Airla Polvnhyler* Tubing 0. IMinnrl Spwntl EP0o.v Enen Coal Tart 1 PkP Urnhlnn IN~phlh, Toluene Blind1 - 0OO.O 0A.C 0. 0a.c 0. 0 00,. 000 0 0. 0 0. 0 0 0. 0 0. 0 0. 0 I- Poivatus PolyCStn Zinc Rich IMEIO IMIBIO I'""""" Ene! Blend1 - 0 0 0 - I I 0 0 1. 0 0 48 0 IUSSERVN 'US SERVIC 0 0 - 0 0 2. The wrking pressure of the fluid hose should be gmter tbur the highest porcmle pressure the system h apable of m c b i n g H o r a ue n o d . ly rated according to the working p m r e and the b u m parun. The type of QIC.~ and the numbex of braids required u c determined by tbe working pnrrure. 3. The tempvoture of the material and the am bknt (surrounding) conditions determines the materid the tube and jacket are made of. (No& anmy solvenu and fluids b e ” e more m t i v e when they are bated). 4. The flexibility requirements, 5. ”he weight of the bow. C. Types of fluid hope available: 1. Fluid All; a nylon tube low p m fluid hose with 1 rubber cover cabable of handling almost any type of fluid, 2 Standard thiokolfhid hose for mort type paints, 3. Compor hose for fine finishing matemk and h a t e d paints (NOTE: Not recommended for water bued pints).. 4. High pressure wire braided teflon hose for rll type of airless applications. 5. Nylon high pressure hose with a static pound. ing wire for mort standard type airless ippiia. tions, 6 . Polyethylene catalyst hose (braided). is the only hose recommended to be used where atomired atab-st u e injected into tbe air stream. 7 . Eztruuon high pnsamre hoses bave an intenvl wire bnid wbkh is used witb heavy mrrtic type mit- 0. Fhid tmmfer (high pnnure) hose dmllu to nylon aillar hose except it does not incorporate a static pounding wire, 9. Electrostatic hose (lowpruamre). a special com. position material, k used in its coastrubion m that it is able to conduct electricity, 10. Synflex nylon tubinp (low pressure). a hehly wlvent m b n t tubing witb a maximum amount of flexibility for nylon tubing, 11. Polyethylene tub@ (low pressure) designed to be used witb water type applications. 12. Retmct nylon horc (lowpnsam). N O T E Generally used IS an air bore but may be usedrsa fluid hose U desked. V. CONNECTIONS A.Hou connections and flttings u e available in vuiour thread styles and riza. The most common thread style used in the spray pinting industry are either N.P.S. (National Pipe Stnight) or N.P.T. (National Pipe Tawed). The N.P.S. style is the preferxed thread used on mort s p n y pns, rir and fluid inlets The N.P.T. t b m d style 6 the common type used for piping. Tbe most common size connections and fittings used &re 1/4”. 318”. 112”. 3/4”, and 1” in both the N.P.S. or N.P.T. style. In wme special Lnstonca 118” might also be used. Sometimes cpehl types ue used such IS J.I.C. (joint industrial conneetbn) whicb are high pres. sure hydnuiic fittings. Airlsr flttings which .IC nomully over a 114” and ue used at high prearure ire J.I.C. BB Not one type hose fitting will adapt to rll types of b o s s Therefore, selection of the proper type conngction necesury is dependent on the following: 1. The type of bore being used, 2. The size of the hose selected-ita inside dinmeter and outside diameter. 3. Method of fpdening the connection to the hose. 4. The thread style and type, fltting size, male or female type, required on the tool, rccersories such IS adaptors. nipples or valves etc., 5. The working pressure of the connection. 6. The chemial and solvent resistance of the wet parts of the connection. B. Some of the typical type connections that are available ue: 1. Reuseable Connections are those connections wbicb may be used over again when a hose has b e ” e unserviceable. They are available for ail production type air and fluid hour. Thir type of conneetion UXI a compression ring which wedges the hose into a ferrule, binding :he connection in the hose. This type connection is recommended for most conventional ipplicstion. . *Note: Without 1 comprrsion ring. 2. Ferrule connections ue used on low cost bore ueemblies. They ue not reunble. D 3. Stmp connections for standud medium pressure hose available in 1/2”, 3/4”, 1” 1.D. they aiso require a special tool for mounting. 4. D.Coupling or Reducer Coupling. This has two female ends which permits two pipes to be joined together, perhaps of the same size or different size. Cbmp Scrra Type m o b l e conM6tiom. used where the hose hr an odd size outside diameter du,used for low cost inrt.llltionr. E. Elbows, Street els or Swivel e l b o w r A fitting de. signed for credting I bend in the line. Standard types have two female threads, not necerssrily the same size and are available in either a 4 5 O or 900 5. Hose menders. a low pressure device designed to repair damaged h w by clamping the hose ends together JRW the damaged portion hu been removed. bend. Street cis are basically the 5 m e except one side has I male thread. VI.FITTiNGS Fittings are small miscellaneous items thU u e used In F. Tees and C r o s e d o r Interconnecting a third or various wavs to intemonnect hoses. piping and equip fourth line into a piping system. ment to nuke up an air or fluid distribution system. A. NipplePDouble Male u e fittings with a male thread on each end; these end threads ue not necessarily the same size or style. Some nipples m y Incorporate I wrench hex in the center poition. They u e used to: U I. Connect lengths ofhose together, VII. VALVES 2. Convert a female thread to I nule t h m d . V d v a ue used in I system to turn air andfor nuid 3. To adapt one thread style to mother. alpply on or off. A. The Upered plug v d v c u a e s matching tapers on a plug and seat to provide a seal. rimilu to a gas 4. Note: They have a tendencs to freeze or ai&when used with fluids. . DOUBLE MALE NIPPLE B. Adaptelshave one male t h m d and one female thread. not nerrvprily of the fame thread style or size. They are used for converting one mde thread size or type to another. Available in either standud or high pewre. B. Ball V d v c r r r e the mort efficient means of con. trolling air and nuid. They us? a ball rotating in tenon sem to provide the following advantages: 1. A minimum restriction to the flow of air or nuid 2. h e of actuation. T h y turn easily under full load p w r e or no load prentre, 3. Wide nnge of intRchangeabie fittings for flex. ibility of appliutioa Available in either stand. u d prreure or hqh pressure types, 4. They an be connected to indicate direction of flow. C. Swivel Adapter or Union k a connetion wNch has either two female ends or one male and one female. Designed with a swivel joint, which will permit one to break into a system or add a piece ofequipment without having to twist the line. 50 C.Air adjustment or needle *-A malldc aigned to regulate a continuous Bow of air to i piece of operating equipment. Uses a needle or stan to rearrib the now. Straight IX. HOSE CLEANERS Hose cleaners are designed to flwh out fluid hoses preparatory to storage. wing a minimum of solvent in iminimum of time. The cleaner forces a minure of lotvent and air through the hose producing a scrubbing action that cuts away paint residue and kans interIor wpli of the hose clean. Advantages are longer hose life. reduced solvent usage. and de. u e w d cleaning Ume. go-oeg. 1 quarl capacity D.Aircontroller-The Aircontroiler is a lightweight valve and pressure gauge Lpsem bly for mounting at the air inlet to the spray gun. It oUers the time saving convenience of adjusting and controlling atomizing air pressure right at X PRESSURE DROP NU. QUlCI$CHANGE CONNECTIONS: Quick change connections are designed to interconnect hoses or i n m h a n g e pieces of equipment rapidly and are availabk in either air or low pressure duid W.Considerations in .eketing these Items are: AForAir 1. Recommended when air line must be switched from one piece of equipment to another quickly. 2. They provide a swivel connection which helps keep h o u s u d g h ~ 3. They can be used u a valve because air will flow only when the stem is mm mom L-2 mcu U I C U With valve d d . pressure is equal throughout. nom mgnged. of quick change dtungs must meet requirements of production spray guns which nominally are 20 CFM .nd 4 PSI pressure drop. B For Fluid. 1. Recommended for paint supply syy5 terns where quick color changing is nee-. 4. Air now capacity mar 1.0 114 Inch 2. Fluid flow capacity of quick change dtrings must meet requirements of p m duction spray guns which nomidiy is 32 n. oz./min. f o r a 20 centipoise material. NOTE. Fluid connecuons, when coated or lined with paint, tend to malfunction when the paint drys. To prennt this, keep connections wet with solvent or .ohrent vapor. 51 m w am XI. NOTES OF CAUTION 1. Always know w h t kind of chemiulr, mlvents or thinners the materials contain m that t h right type fluid h o u and connections m y be selected. 2. F m U i i z e yourulf with the materials used in the construction of the hose that you ue deal. lng with 3. Never exceed the mommended working p m m e or temperature of any hose. hose or flttlngs for high pressure ipplicattiom. 5. When working with high prerarre d e s hose. never bend the hose in LESS than a 4“ d i u , otherwke it will kink and m y burst. 6. Check 111 connections to make &in they ue tight before turning o n the air or fluid supply system Eye protection should also be used s p c i d l y when using dangerous mat7. Always use proper tools when working with I an open end wrench, box connections. such . =“h ! k e or adj&ble wrench= Never use pliers, v k @p, or pipe wrenches. 8. Do not lose or overlook the comp&on ring or &ewe f” connectiom wbere this method k used to bold and sed the hou to the connection 9. Always match proper pipe thmd rita m d 4. NWR use standard p- 10. Never open partiilly a valve or use it for regu. h t i o n Always h o e It open or dopd 111 the way. Disreguding this wU ause the nlvr ylts or stem to wear out prematurely. or %ire dnWl”. XII. GLOSSARY OF COMMON TERMS FOR HOSE AND FITTINGS AIR HOSE-A N h k r ho+c nude espcidly for sup plying air to a s p n y gun or other a i r q e n t d equip ment. Binks u s 6 the color red to desigmte air hosc and it comes in the following inside diameters: 1/4”, 5/16“, 3/8”,1/2”. 3/4”, and 1 Inch. Brown ls uud to indicate an air hose with a static grounding wire. CENTIPDISE-A unit of rlcority. conveniently and approximately defined as tbe viscosity of n a t a at mom temperature. The following table of approximate viscosities i t mom tempenture m y be useful for mugh complrison. Liquid V i s i t y in Cmcipoita Water 1 Kerosene Motor oil g10 weight SAE C.rror oil 10 100 Corn oil MoLees 1000 10.000 100.000 CFMih-Cubic F e d Per Minute which k i measure m n t of a T O I U ~of &dud air mewring 12” I 12” x 12” p i n g a given point Inone minute. COMPAR (Hot bcqun Hod-A rpecLI nuid hose used witha piastic lining when hot spny work ls to be done; never to bc used with a water based materid HIGH PRESSURE HOSE CONNECTIONS-Used on I nylon hqh presswe hosc for rules spnylng. INSIDE DIAMETER lI.D.)-The h i d e dimeter of the tube, hose linlng or fittings. J.I.C. CONNECTION ( h i m Industrial Commission Connactionl-Theseconnectlons ue g e n d y used by hydnulic or electronic industries and have been used in some rules application& OUTSIDE DIAMETER (O.D.)-The measurement amp.t h outside diameter of the jacket of the hose. p3.i. Pounds Pa Squin Inch Is a measure of energy or force ahow ivacuum. RE-TRAK HOSE-A b o o that k Wound in a coll and rill spring back into a compact stre when released. This nylon hose k milahie in I/(” m d 318” LD. It may be u d for fluids too. STAINLESS STEEL HIGH PRESSURE BRAIDED HOSE-Urd for d e s ipplicationr m d is more flexible t h n h i pnylon and more solvent misun: WiU lLC0 withrrud more ahuse and has a I O D ~ R life thn the nylon bigh ptype. STRAIGHT PIPE THREADS-A drrdud t h m d system b a d on pipe &iza uod by BinLr for moa air and fluid connections on rpny equipment. Relier on ’ matcbing Upud o l t s to provide a seal. STANDARD AI R-Is denned as one cubic foot of air i t iatmospbaic of 14.7 p.6.i. temperature of 680F. and a humidity of 36%. STANDARD FLUID HOSE-A Nbbcr hose made q e c i d l y for supplying mataid to a rpny gun. CM m u & be taken in choodng i fluid hose with the proper tube m that the mlvents used will not attack the inaa lining. B W supplies this hose in black and is arnitble in the m e si26 . I the air hose. STATIC GROUNDING WIRE-A wire built into a hose which k used to ground the spray gun Y) that there b ’ t an Clectricrl charge built up in the rpmy gun or opentor. SYNFLEX HOSE-A nylon hose, m.ky white in i p p m n c t . used to any fluid m d solvents which noraully lnect r u b k r boric Advantages ye light weight, chemially I”,cleans asily, minimum p” l o q tnnducmt and low in cost. TAPERED PIPE THREADS-A standud thread sys tem found in -dud plumbirg system. Relies on interferena of t h m d s to provide a d i n g slrkce. TWO BRAIDED CONSTRUCTION-Whereto bnids of reinforcement is woven uuund the tube giving the bore higher b W strength or working pressure nting. WIRE DRAW-A term used todescribe the p r m by which hydnulic erosion WPM i a n y i portion of a d v e o l t or dem / CompressedAir Supply 1. COMPRESSED AIR of the canpm is kept to a mini".When air is expanded. due to high temperatures. h e on-off running cycle will be imrascd. D. Cubic feet per mlnute (C.f.M.) and pounds per quare Inch (pd) Cmpmscd air is "red on the basis of wiume of air u . 4 (C.F.M.)EI. a given presuur (psi). The reference to volume of canprcrred air is alwdys a measurement of air in iu free aate; ar standard atmospheric condition. The following illustration sbwr a cubic Imc of free air, Mlparrd IO a cubic loa of air c0mpm.d IO 100 psi pressm Canpressed air k atmospheric air which has been m e c h d l y f O I d kt0 1QCngC fhamkr Undn p a V e d then, With 1 means of u " l . relared to perform a spedficdrrr of WrL. This atmosphere. the air we b d . m i s s of rpproximUely 78 percent nitmgcn and 21 p a n t oxygen. Aii has weight d this weight'is called atmospheric pressure. At sea level this p m m is 14.7 psi. This m w s h a t the air p m m ucrted m evny quare inch of the eanh's surface at sea lcvel is 14.7 psi. This pressure is alm umed IO the sides and upwuds fromthe eanh: therefore when air is at the canpressor inlakc. h entm with the presm of 14.7 psi. A. AitRude The atmospheric pressure and density of air dccrcpsa as the a l d ~ d cin-. For example: around Denver, Colondo (6ooo h . ) t h e a t m o s p h c r i c p m L 11.7psi.Duetothcbwcrprrssure and laxr density of the air. 1 smaller (output) quanlhy of air is delivered by the canpressor. Air delivery of a e m p " i s reduced by appmxima&y 3 percent for &cry l@X~fcctin &muon a h sea i d . B. Temperature There is an ad~ f on fan air ~ cmpmm'r prlormylce when lhe inlet air tempcramre rim above n o d . sludud air has k c n defined as being 689.. having an umosphaic pasure of 14.7 psi. and a 36 percent relative humidity. Stpndnrd au IS w d when tesls M ma& and effiacncia cmpuud; sund a d air is also the basis for rating compmmrr as to volume dcfiww cauabilida. Sbould thc tcmDmNIc r k sbon 689.. there 6 11 a 105s of air delivery e&alcnt to 2 "cent for ~ r y l .O 9 , i n b in air tempcram. Far aample: if a canpmsor IS operaung on a summer day, ar in a hated mrm aith an air t e m p t u n of 989..thm would k a 6 prccnt drop in the volume of air d e l i v d frcnn its rated capability. Tkrcforc, haw the compmsor inaallcd in a cool WaiOD of thc plant ar mr a window, where good air drculation can be bad. m - C. Heal of Compression Air from the discharge side of a compressor is h a becaw it has been canpmwd. The temperatun of discharged air rdnga from 1509. to 500"F.,depending upon the typ of cmpresm and the working pressure. The higher the working pmm. the p u r amount of heat is gcncnlcd. W h e n this heated air g w into the air rccciver wc m e t i m a gel I falx reading of thc air gauge. As the h a t is dissipated from the air receiver. the temperature drops and the pressure will dmp eYCn though no air is being uwd.This is becduw ha air requires more space and. conversely. cold air, having p a l e r density. r e q u k less space. In order to have a -me"volume of air in lhe QOngC lank or air recckr. this temperature m w be brought to room cf rurrwnding tempentun. This is done by means of an I f t e ~ dWith ~ ~ . a -me*'volume of air in the receiver. ihe on-off running cyde Note: inncara,volume dmcaus. . . mde O f d OT Nbbsr C U U p i h . Thir UD prodUCC 8 lchivdy high lir wcplt la the mQoT S L r Tbc canplavd lif delimrd is vrullly oildhe, but na moisture-free. ud presnues M in tbc 30-35 psi nnge. Tbc diaphragms and AVM muire tqlaccmcnt horn time (0 time d e p e d i on use. Tbe bouring die u l t h L l i Q g 8 hri2ed e m U r U C h . bUh h10Ct i c 4 uid .ctrhetic in design. Wbcn sad. chc uni~will run cmsatly, b“,hey be &signed for automatic moff opcmtion. Ewasive air p~tsslmis r e l i e d bough i built-in unboder nlve. Thic unit m a sun agninn bad-dl air must - beIcmavcdf”thecwprcsvlrbeforc~. Diaphragm comprrrrorr vc designed for intermittent openh,bm a t ud generally urcd ly the mer.small plin* umuaclor, or bobbyin. B. Rotary Compnrron l h i s type hu become ~ a POpuLrduring y the p u t few years. ’Ibey LR usually quieter. easier IO insull. and lerc upearivc ~rcciprocatingtps.This d a i i s bocedm the oprndng principle of 1mor, filed with nnes ecccnrrically mMlnrcd in 1 bousii. During option. the nnes at held against the houing by centrifugal force. A lubricating lluid is used in thac tps la bah d i n g 4cmling. RoprmsiDtenrnce of the sq~mttmin tbae canprrvon is my imporunt IO prevent excask wry mer of the lubricmt into air system. An absorbent type flier d m s v r p m from the unit would be te“dd. C. RoclprouUng Alr Compnrron This type is thc l m S t c I ” n ~ Tbc . pItsslm dumberamriro of a pistm htled arih automain type pistm rings. a cylinda and intake and discbuge n l v c ucemblies. Com- 8 MAKi air calm1 dcvica. .piIating opmtials. pneumuic .wp1cT arp ply systcms. t e m p r a m ud insrmmcnt cmud. 6n p” sprinkler systems. liquid or solid msfcr ly canpared air. uid cvcn rodent conml. Howcva. hem UR will IOM our menhm mmprcyed air .ad iu usein tbe rpny plintbgimiusq. hm LI cbm LR “y w forsanpnsed air, mac Ucmrny tps Of”prr+uns. Each type of air C o m p r s a a puticulrpurpo~e.Tbe b m ~ t l uwill r dcsaibe n k diffn~ a t tps of comprrYors. their dnnuges lad limiulias. A. DIaphngmTypaAlr Compmaaor4ll-Free This is 1s d l hand Unied ~ f a s m p l plint l rpptUbons. Air prcvurc is dcvelopcd through.& reciprocating or oscillating action of a flexible disc. Normally the disc is parion can tskc pLce on either si& of the piston or m bah rides. W l m ccinprusicn rnlvs phx on both sides of k piston it is d l c d double ming. For genenl plrporcs the single aing type is most commmly w d . Single acting comprrssors CUI be cithcr single suge, or IWO sage or multi-stage. air or - antacoded. When air is dram tiun the atmosphere *ad cmprcstcd IO I given prcsrum in a single mok. k canprrrsor is a ‘single sage” unit. S i l e or multiple c y l i ” of cqwl bo= size may be employed. nKse units produce p”up to 100 psi, sam M.11 fractional H.F! units of this ryp habe 150 psi capability. Tbc efficiency of single stage uniu mr 100 psi is ycry poor. Operatan mr 100 psi is ucually nu recommended. 54 TWO STAGE COMPRESSOR 55 Ill.COMPRESSED AIR SUPPLY SYSTEM be canpressed air rupp~ysystem is designed to an dcquuc alpply of compraced liru aprdctcrmiDcdpaam m efficient opcntioa of .U air-opntcd alui~mmt. IyacmCpI ny in r i a fran a d. h.ad clnicd unit to in-* ' m &if ~uircmenu and cm&j"sflJrtbac sywmue the yme: 1. A sangnrror. romecimarefemd to a s 1 bad orpunp, UD be mc cunpmsnr or iseries of c a n p " 2. 'Ibc p w u m e can be an el& rEuor, 0rpoSs:My 188s * . we driven udit. The component units can be combined, or maraled iDdirrclly on a c o r n " hre, or mounted m up+ne foundations. Drive connections most commonly empbvea ue.bcls and couplingr. 3. A c m m l or s t of conmls regulate the o p n t i o a of the rmmlndclnl~. a. The control can be a constant speed unloidcr which lllam the canpressor to opnte conlinuousfy, maintaining a pmet prrsr;un without awing the maM to stm rad stop. This system is genmlly utilized m pwuble when compressed air is emlinuourlyr q u k d ty @uctian equipment. b. The inlcrmittent type control is basically a pressure milch and is IrrcdmelcQriCS U t i o D P r y a m The ~ prrsune switch mpinuins a "CUI-in". bw prrrauc point. br example. 80 psi. WYCU the prrsave in the airrrccircr drops to this bar point. thc maor will stm and the ampnrror will then pump up to i& "t-off high prr~nvc point which m y be 100 psi. thw brrrLing cmLcc and stopping the mator; when fbc prrrauc dmpr to its bar point. cbc cydc is rcplud. c. Illere h c l u bc acombinuim of maefmbdr-cmIUD1 spca unlodaand prrram $wiIdl. TaL combin, tim is = f e d to as dud cmrmlr. to be used when air deaudc nry. 4. Air intake fillen or silencers, or a combination of both silencer md hlm. are 'designed to mume intake noises as 4as hlurout dun and din. The air fileris wy impofi.nt as dl air going in10 the c a n p r w u mun pus lhmugh mir film. The Nter element must bc mr& of fme msh or felt mrcerinl in ordcr lhll small pudcla of grit ud lbnsk msl d o n a pas into the cylindm. thus pmsnting d WCIT m cylinder 4 s . pistm rings. and nhei 3. It is prcfenblc to h a w i mcansforcodingthe dirchpgtdair before it enten the air rcfeiw. The m01t imporunt can" medns is a unit knom as an Incrcoder. An lfiacoolna n be made in many wyr. The most efficient is a arrursodcd unit which brings the discharged air t e m p e r " down to within a few degrees of the inlet ~ t e ICInpenNR. r An .ficrrooln is a necosvy pan of a good ~nprrssa syrum d is th primary requirement lor m o i s m " I . 6. ' b e air receiver must be properly sized. It c m m be ma rmrll or it will cause thc canprcnor to q d e to o h thus causing cxcevivc load on the motor. It should nu be too large because of spice problems and alm unnecessary apaciv. On a portable canprrrcor, cbe lir mim can be relatively small as it acts. primprily. u a pululing chamber ruher rhrn as a norage lank. 'Ibe Bumu of Standards, Washingtm D.C.. has st suIId a d s designating the minimum size of air receiver to k raed bprcd on the air displacement rahg or the h o r w p w r for any given compressor. This has been accepted by the ramp"ri"yrrast"iandis*nnllyIollaKd. volume of l i r for rhon whp an q !e"rcquLa a periods. alugc airrrcciveris frcqwnyld. Using luge aongc unka and mull ampresfom is f i l s , scmany. This ccmbinrtim wuld q u k the air c a m p r c ~ to ~ ropnu lor a longer pmod io maintain ldcquau volume. R c m d of this storrd air is nry npid md UD m l t in a temporuy shutdown of operations undl the compr~sorbuilds up the air rcfeim IO is full capldty. The only working air chat is mailable is what the comprcnor u11 produce rciording to iu r a d capnbiity 7. The in~mneaingpiping. mU is. the piping beween the complnd h e receiver, can be copper Nbing or gdvanizcd iron pipe. If the unit is wncr-cwled. this will a p p l y m t h e p i p i n g u q i e g s t o t h e canprrssorand carrying W " y to the dnin. or to the wm-cooling w r . 8. 'Ibc disuibuticm system is the key link in the canprrsred air system. This is cbe hare or piping, or unngement of hose ud piping fran the & miVa to didbution poinu rcquiring mpressed air. This disuibutm system consists of the pmpcr shes of hose or pipe. finings. valva, air NUIS.oil and wter c~pIRors.regulators. gauges, lubricators md such other items that will provide for the effective and efficimt o p t i o n of rpcdrc air devices, tools. md spraying quipmnt. a. Thcpmprsia of piping 8s well 8s the " i d it is cmstructed of is i m p o m t . Copper tubing would k the bat. thn galmaizcd or blpdr ima pip. If cbe canpmKW quires oil lor lubricntim. the air hare must be oil h w the coma p i p size m i s m t . The fdbwinB Chnn s ~ in b. Thsc uebasiicooljdmhsand will have to k modihcd to manmodate the piping fw a canprcsxd air syrtcm in .ny prdcullr hution. At tima. 1 customcr m y run a " p r r r w i n Q buerqent or from a mck and the hare or pip m y goouuidc and up IIU or four C floors C ad back in10the building. If this wm the SiNauOn ad ic (v1s cold outside. lhen c a d e n s a h would bc a pmb km. ODC d d have freezing of the hose or p i p . This is inadequate piping even chough it may be of the proper sia. h i s good pnaia if the plant is kng and narmw to instdl an exira air receiver at the far cod to act as a cushioa and help reduce prryurc drop when peak loads ue plnced m the compressed air supply. F'msure drops. IO a p a : extent. UD k m i & by encirding the plant- or boping the distributm system. This is accomplished by running the piping in a full cirde or loop hum the air rrccim around the pLni and back OI the air receiver. A double bop or cirdc is wcanpliskd by installing a tec in the lim and then running a bop orcirdc in bolh dmctimr back to the air Y C C C ~For ~ . this ryp of insllllaticm it is ncanmcnded that an am air I U C ~ k ~ inslllled at (he 56 far end to baiana wt p k loads. mw IV. CO"wwmIN SELECTING AN AIR COMPRESSOR A Appllcatlon Fm.d y tbe apphlim. Fud out whu type and how many c. whst typ of film,how many,or what reguluon rbould be installed in a compressed air system will depend entirely upon the intended end uy of the air pwr Oac inmlhticm may bc uring quipmcnt that requires oil lub ricltj, lor air t d s ; h e then an utanrtic line t u b M should be insullcd. In anuhu use. wherespying is dme. a lubricator wwld meate a problem. Rcguktion of air is vcry imporant. Less air is consumcd w k n urtd at low ptnaur:than at high prrraua.Thereh.if1 t d can be opcratcd u 5Opsi ud plMt air is 80 psi or lW psi, 1 regulua should k instnlled to mud tbe air being supplied and i t iu k t opuscing .p msquently using minimum volume of air and rffording Iwropcntingconr Airline film or urnaorauc necessary parts of compmred air supply system. No nvncrhow wcll the unit is W l e d tbm is alwyr tbe possibility of contamination in air lines. Ai Blms or umam of the absorbent type arc tbe b a t for this purp; h w v c r , drops or drop kgs can k &. d. Ihe nuin discharge pipc (hcak) Wing the air ncciva should k slopcd away fmn the comprrsx thrwghan the entire distance it runs, with a d n i n s f f 11 all low poinu. The take off from the main header in the lir supply system should be f"the top of the hcdcr. Lasull 1 tee in the main M e r facing upwards wih two elbows returning back d w n t m r d the E m . This will keep condensed moisture from entering the mol being ured. 'Ihis d a s ma. houcva. prcvcnt moirmn t h i s cu mdenwd fmn entering the mol or the line. THE PROPER METHOD OF REMOVING AIR FROM THE MAIN HEADER air consuming d c v i i .IC cumntly b c i i uscd. what the air caxwmpbic f o r d tad. ud w h a l m u i " p r r y u r c r tbill b c m p i d for any mc &ice. 0n.x wc know bmw mvch air is & UDdn m n t openling wnditiaaC. rmuidmcion g u l d bc g h r n p m v i r i forthe fuan d d i t i m o f l i r ~ devices This anticipated requirement should be added to the " ~ rystem 1 requirement. In dditim. a safety f w of 1 last U percent must k allowed to compensate lor b w c d efficiency.luh. unforeseen contingencies. 'life t w l of the .boK will give ur the required capacity to be rocanwndcd. Qlaru uc Milable S h m i n g the air c " p h ud ptnaur: nting for various trpes of air opuucd quipmcnt. his wry imponnnt that h e canprrssoryou relea is the wnui type and size foryourraxls. Scludor chpnr No. 1 and No. 2 tvill hclp you mpLc the p p r choice. 6. Pmasun whm is me h i g k t prasurr required for anyrirdevice? This will de& whcha or na )vu will quire 1 single sage or two stage c m . C. Typa of Unll DeIaminc what c m or UmprcssoIS uc to be rcfanmended. One should always rmuider the poyibility of using nvo comprcson. ax b e or full UpaCiIy unit brtbe d. full-rhin vmking dly and 1 rrmllaunit fortbe vford rbift or panid working day operation where full u p d t y is no( requid. Tberr uc llromrnycascs W k me rarl air quire"1 is supplied lrj la4 "-; chis,cln LIsllc 1 constant s0lu.a of airsupply in the uce of flilm or l "m ' OfaK d me unik In operalion5 W b air suppry is critical. 1 Mmmm pnccice is to provide i sundby unit and normally, this d b y uuit is opnted almnmly m a weekly basis to insure PoprfUDaioning ud WOrLing Nlilabiity. The combination to be selected is Io k determined by an mluiticm of the needs id economic factors involved with tbc p r q u n i g h t given to cuh. 0. Controls In &torelea . ud . pmvidc the p"typ of ccntrol q u i p "I. 1 dctmrunnwn h tok made as to the openting cydc of tbe comprryor. This &"hation will be mpdc by uamining the UWI 10 the lohving questions ud then relating the mode of a m p " cpmtim b a t suited to the inended use. 1. W i l l the air usage requirement be intermittent? Here. an utatutic run-stop control would be b a t ud set u)that the opcming cyde ntio is Ipprorirmcely 113 running time and 213 dum timc. 2. W i l l tbe air w g c requirement be fairly constant? Here. I amsuit service c o n d w u l d k bat. 3. Is me air w g e pallern 1 coolof me lbove, intennitmt during YIlM pnodrud conslat u ahar, rothat PJ hm an imgukr requiremenu s i n " ? 'Iben. in such an inruna the b a t u w ~ e r i tso h m I dlul c0n~0I--bah the iuvxlutic sun-stop ud constant m i c e inrutlath. This permits the w r to obtain the best economic h u g e in canprrya op€" in this drcumsuaa. Ibc pmardecdm rbould k dctcrmiasd by am of p h t b mode of openth d mticipced fucurr mob 0 nrb opndao. Mury rima (IY lypofccmrml will be selected for the immediate need with pmviricus lnade forthe d d i I h 0 f the dtcrmtc mafml. MNJN some rddltlonrl SuggOStIms: 1. LiadI0ftheliropvrleddevica)auexpnto~fmmthe compressor with the average free air consumption. (Use aun No. I for clplcities) 2. TaJrheseflulirCaWm*figurrr 3. Nae the highest p+ssurr q u i d to o p n t c my rml. 4. Fa inlermjmnt vrvise refa to chn No. 2. cdumn A. Fa n "~ v h a Lodr c LIC in CQISUDIISC. uucdwna E. a. Deccrminc prrzwc m g e nu&d fa opcmtioo. b. Within this range, hate total camnpfim of tmlr c. F o h line OCIOL( to the ~~cmmended B i Cwprrs$01Model Numkr. A v e n i e *k Coar~mntionof AirPorered D d c n c 16. 7.27 2.2 7.29. 1.8 7.8-1 1.9. 4.24.9.. 1.8 E. Voium al& lircanprrva dMcd for the Mlrld u m (cfm)dclivered. n a for canpurcd ccanpnrcor displfcmcnt. A d e of thumb for figuring rcnul cfm delivery u 100 psi L: EleCPiEMaor = 4 c f m p e r b o n e p w r Cis Engine = 2 cfm per honcpower F. Elrwtlon AI what ~ I M I ~ is the ~ Ycomprrssor to opntc? A canprayrc bra 3 pment in efficiency for every loo0 fcet of elcntica. G. TOmpWJtUN What will the (ambient) surrounding temperature k? The higher the ambient tempentun the more m o i s m the & can contain and therefore. the Ius air the camp- will pump. Wamsooled units might be required. n. VOkJgO I~M el& maor is what d u g e and phue ue q u i d or available? Nae: lor k dp w r cost. mmm of 2 h.p. ud L r g a should utilize higher voluga and thrrc-phru current. &. 1. Loullon Will the elcctric mmor m the compressor k in ihuvdwr h a Q a ? A rpci.lcrrpbipm0f"risquirCd wbcDHa dust or g u mly be prrvnl in the Lwirmmcnul umorpherr. V. ACCESSORY EQUIPMENT A. Controlr-El.strlul 1. Pmsure Switch: coauols starting and stopping motor i t ret ptuwe. W d to maor lads k w e n manual s m r ud motor. or '2-way pila" device in magnetic s u e r . Wbcn air pressure reaches cut-out p i n t . the contacts in tbc pressure d t c h open and stop the motor. Cmml can k adjusted for vuious prruurrr drpmdhg upon requirements. NOIC:never change the pressure switch without cmrulting the "ufraum. 2. Ignition Stop Switch: Grounds out ignition cumnt at ret prcssun. stopping g u engine. Engine must be resuned when required pressure is to be supplied. Conucts work oppaitc to thc of p"switch. 3. h h d SUna: Uruplly hu sun-~topb u m in UNCI with arrsabunm vadcrthe ccrverlrud when the maor has kea rbutdavll bcuuw of an omlord.uudprimvily for mO(0r protenion. conuins thcrmil overload relays which will open. stopping motor when overloaded or low voltage occurs. Power line goes dmctly thmugh mmud SURU. ducugh p"d u b to h e maor. 4. hrgpetic Suns: A more diable mclnr for mota placeCoo hr a p w h - b u m p a d to mad m-off opemtim. Lo mL, mc p o m g a r uvarph runcrdirca to the ma. using the p"switch u a rrwo-pde pilam .crintc a mapoetic coil whish, wbcn energid. c a w cbe c m w to meet. f d h g pwrdLsl to the maor. Thir isthebcst mbodof mdor paCnim. espec*lly for m o m larger Ihan 2 h.p. 5. Fused Disconnect Switch: This is iknife-type. off-on switch. coouining the proper sized furc. This should be prcd It a DCII the c m ~ u n i wiul c the liac going han the hued dircmnut 10 the s u k . Fuses should k hrge eaougb to hudle 2% dmcr thc m t ndng stamped on the "r. A qualified dcarich should ah^ m k cbe elecuiul bookup of m air mnprssm. B. ConholcMsnwl I . Lodlar SWMg Mcchmiul. Tbir is, in c M . imcuu of Leeping tbc comprsm from working until the m o r EM revh its full OpndnD sped. ky lrccpmgthe suning load of the mdor u its minimum. a. Swim UIJovling Val=: Most air cmprrssors ISC this mum to recmoyc che bad fmm the cmnpresor. It merely bolds tbc s u c h (ainuke) whe diu off its scat when audng the mnpso that when air is b u m into the cylirder a m rbe inuke srmk it is exhausted through the open inuke nlvc preventing buildup of prruurr in the cylindcr ud, cmsquently, h e maor d m n a wrk during chis phru. b. Diaphragm or Piston Unloader: This is the p i n which opens and closes the suction nlves. It consists of i diiphngm or piston (that comes in contra with canpaced &) ud a linkrgc ora pin capins. which operatc m cbe nlve disc causing it toopen. The lir to opentc the diaphragm or piston unloidcr is controlled by I pilot nlvc (>wry de)WM in ~WII is controlled by prrya speed. oil prrzwc. or ail p==ue. - 3. Ikrl cmaofr. This u a combO f W me mstvnirm (hindmt opntion)ad t k mat ~peeaunl~rder(for cmtiouwr opruiao).tbc durl armml cmr*o of rh ekmcatt rapuind forsunpl- & pikc wrbdn. a ShUIoff nhr rad UI airopr& nlvc. The rhut-afl nlw is inrullcd 0 che air ida ride of rhpikt. nK pila is sa to opauc .(1praaur m l e u c IO psi k b w r h ~ ~ mrinp. u h -the nln is dosed, che compressor will opente thmugb the $witchmud(iitcrmimt); with che rbaofldw qm.me C a n p r r y o r d operuc W U B h Ibe pihc lmkakr (cminwuc).n e UIQ glinsbeaefur fmm IhL. becloopr.IC the unit m conrunt speed when the d e d lor air is @u rad t. can switch toinramimtrcrvicc WheDdCmudis small or to merely maintain pressure lor small jobs. Tbc rmrll dditirml COM of durl cmrrdr is 1vcry arofiharhile imamcat for my customer who may have a tluccuaIing * dnnrrdforiwmpascdair. 4. Uand Unloadcr. Uand unloading is simply taking the bmd f " a umpby manually keeping the in& or nutim valve off its KPI. The unloading is accanplished by muns of a auction unloading n l v e and a scrcw-rypc or kva-rypc linkage thnt is opened by h a d to force che in- ukc ntve open. This mcaac is ucedprimrrily w h r r a c a n p l a s n i s akded a d y ocusk4lally and is avmd m ud off by a mrinuMnct man: typical insullations k i n g Fm RacnioD md Wucr supply Svrrrmz 5. G u Engine Idling Wit. This is M air-opmted dcviEc mu. w k n iarullcd a l a gas mgiDe driven ccmprrsoz will C.UIC rh engine u)idk when mCsanpasl*mdmio Y( pressure. As cbe c o m m unloads. the air bolding the diaphragm d w n is also applied to& i d l a c m u d m t k engine Tbe i d l a control. in nm.pushrs %aimthe cu- ~ . s e n u c b r i n b r ~ c o " . 6. W w r ~ f n w u e r z m l c d .fm~ d Wden VI. PREVENTIVE MAINTENANCE A. 011Changes. Fdlow faaw nm" inchmging oil. Most manufaaurcrs require an oil change every 9X hours; sooner if cbe oil tccumn dirty. Use a nmdcmgcnt, oil(dimatid) or rpccul oil devebped k r air wmpersorr. Oil will cktmiomu due tochpngiag tempknue and muminatim fmm lbsorbed dirt. Note: Saw smnll porublc uniu do NoTRquirr oil. B. Inlet Flllsm. huc rad dirt arering rhrwgh the inuke can cause rmsiderpblc dunage to h . riup rad cylindm. Fdmbecanedogged rad CllldmLe the in& c r d q UI exEcIsiw ylfuum. thus curring 'Oil pumping: ' C. Bslt Adjultment. New 'V" belts will saetch slightly lftcr about one week of operation. Tbcy sbould be adjusted at that time. Belts should tlex about 112". If they are too tight. and excessive load is placed on both motor and compressor main bearings. If they are too Loose. they will slip causing them to wear excessively; a h . the compmsor may run slown real- in inefficient pdn"c. D. Working Parts. Tbc old rd.ge--'m ounce of prevention is wonh a pound of cure", C a n be literally interpreted 8s it applies to maintenance of a compressor system. A periodic inspzion of valves. rings, kpringr, contml mechanism and a h r puu s u b j a to wear rad their replacement wbere such is needed, can pment costly breakdown which may occur during critical productim priodr E. Dlatrlbutlon Syatom. Small air l u k s are costly and tmnccarary. A pcriodii soaping of dl connections a d the ccmaing oficakl will gunnlct &dcnt ~ n n l n c from c the WmPleJra LNJlemrCcild m.sbwiIlg IhccrlgiDe. WbcnchepKsuTC F. Clean Air. Thc use of .flcrcmlen md proper typc aten dmps due t o p " b c i i d d -the idkrs"J. acxuauon is auntid in hwing a dean rad dry air system. the comprrsror R Y L ~to pump -mg tbe s p e d of the ~ ' I h i r d e v i c e i s ~ ~ f o r u s e a r i l b t h e ~0.2Dnlnlng Air Recelnr. Tbir may be h by opning the dninnhr (daily) al me unk ainnrlling 8n lutanatic dnin. Cv-c. satsty Acceuo*s H. Rating Tho Air Recelvw. Rriodic testing of the air 1. A safety nlvc is furnished with ocb c u n p " unit .odis r e s e i v e r i s I c 4 ~by mrny Nte rad bell coda.Asreceivm ret to blow before the pmsurr rub rh nccd working begin to age. mci l b i t y to opruc uadcr high prusure loa& pasurc of the air rrcciva. nK yruy dw is to be lotcd begins Io dexrase tbmInc. hydmsufjcmling to validate the paiodrally to m a k sure it .&si Not.:If it is DQ air rrcciver'l A.S.M.E. kbel is q u i d . 0pCnf.k.or the oprntim is sluggish, SWmQI smsc dicutcs that the valve be replaced. Compressed air can be WI. TROUBLE SHOOTING A uur A Low Air PNsrun. Tbc custaner says he d o a n a have dangerous and its pmvcr should be given due enough air or rh.1 his pmavc is na high enough to o p n ~ who attempts to opnte a comprrrcor with the safety.n l.v c his equipment poprly. Thc uuse can be amibutcd to one of DQoperalinp.ldefeaive airrcfcim, or any "trig maol device 00 the unit can apa to encounter suioui the folbwing: 1. Insufficient &pacity. Gcnenlly one will 6nd Ihat the re~ucnccs. quirements for air exceed the supply-the compressor 2. Bclt Guud: Thisis 8 safety devLt Ihat islegally q u i d i n docs no1 have sufficient capacity-primarily due to the m01t sum. A comprrssor unit is to be insulled in rmrd subsequent addiam of air dcvioa. Here ihe lolutiOr, is to with &e manufacturer's recommendation that the pulleys provide an additional compressor or replace the present face a wall. hereby dimking any possibility of &nu unilwithODC&ViilLrgercrpuity. D. Ylscsihneous Accessorbr larufficient capacity can bs due to a dfunaioning inukc 1. Flexible hose connection betwen air rrccim rad piping valve. A very simple check can be mide to determine ryrcem. wbcthcr or lkx the unit is FcdCmbg properly. Fmt, RmOYC 2. W t d i m & . b e air filter from che inukc on unit ud hold chc palm of 3. In& m1Pr uld SiIcnCerr )wrhnd ova& in& hole. U w h u d is dnwn to the 4. Handler and holding brackets for hoisting portable air hole ud held tight by maim tben p u my assume the c w somprryon. , p r r p r x i s o p e n d 4 s ~ff.bomrpurhndis ~. n a held cight but Nheris buffed bocfr o r p a f d1 p h i l l g facc m me pdmofpmw. lhm me* in me unit ire n a sating proprrfy d tbe&tbrt is being drwp into Q comprrswis b c i bbvDbn2 wtthmueb me dischrrge. if it is n u btiq crmpsscd t b ~ @ thedie nlvc into Q air r&civa. A slight lclk in.= in* *spLreducC meeffidmcy.'Tbc r c d y bere istobm Q ryacm iroomplndy d c d ud drcmnlr i n e c dkaica. n n y b tbecomprsroZ hkallyrruoolblc IOthu my forcia rmttcr in the air iystem b u puscd lhrough &e campesrnin* oris me rrrull of smefhhg t h u h t prrced lhrough I h e c n " i n i n u k e . This ismemlyvay airlines in icomprersed air system can become coauminmd. What cause3 mu"? Tbe fdbuing uc rypiul: I . Moisturr me unit "i. Moiin~euuy( pipes to mt ud.Lptcru it dries. scales uc 2. Inadquite Piping. The inside di.wtcr of tbc p i p is (00 formed Which bKak bac ud M urried in the airmclm-to dto~tbcKquireddvduminIgivmpriodof~ bdge in 1VdW S W OT @Ug 111 d e 1 IO M & &am l t i n g in clcersivc WC.I or malfuncticaing.To rcmm 'Ihirsmk rbc main l i n e , b ~ & . ain many ara.QEmoistwe, lir must be coded below its dew point. prefcrably miaed flow is c a d by the rubberhaK utendjng to Ibc be& it is discharged into an lir rrccivcr. Air d e n canmd. By rcfming to lir capacity Iables orchlm kr wious prcssedir ha, rad it is nccusary to wol this air, to force size base rad p i p . OM uo determine wkrhaorwC I* cmdcusatim s o ~ t o ~ resulting p p ~ Mtabeforcitentm uuna hu the proper size of p i p C a m p 4 air should be the canpressed air system. l l lir ~rseivcr ~ .Nas 111 initial delivmd to itool with I minimum of pdrop. The -for was, radoil. butthis is nuits funaion;it is M air d y ties in eitherinacrci Q size of the p i p 01 hm. nmge rank. orifthic is i m m , toprwidc 111 UlditiaJlIcomprrrvn in the uu w h m difficulty is h e i q encouowd. Anaher The moisture cmmt of tbe auwrphm nris with temprremedy would k to 'bop" the disuihution system.lhacby mnc. Whatever the moistwe m t e n t of air is wbm it cntm m i d q drastic prruurc dropr. In this typc of distribution the compressor inukc. the air temperature king funher system.the additioo of a lir m i v a w i l l insure I nircdbytbe~ofwmpmsionrrsuluinimoisnvcmbem smrrd of linc prrrsllrr. It is g e d y rrcanmclujcd tent m b t i o n to a higha ydpor state enahling it to k h t h c minimum p i p size touy 8s imnin be should mcuried io the air meam without difficulty. As lhis moiscua k l a than the sizc of the canprrundirchnrge opening. r i d air tmcls lhrough the system. the t e m p r a m will hctors to carrider M hou,the air is king 4. the numkr dmp uod it rcyha ram u m p m OT i u dnv pint, then of dtopoffs. md wherha the air is being wd cc"fly or the moisture in lhis air GQdcnrer ud is the "e of wur intermimntJy. U the shop is large rad the main line Ius I in tbc system. Thc pmpr method of cmaolling this uadicanidaablc dirtnaa to mu, t sewad air nceivn ianrlled tioa is to rrce I waumled IhcMola. By "ingcod wpu the far end of tbe run would hclp s t D b i prryurr.h is ter through the rftcrcwlcr. rtducing the air umperaturc Icrmetiwr more CCmOmiul to dd ID airrraiwthul to bum .bwl4oodegrra to lbout 70dcpm. tppmrimucly hm Dcu piping installed. 90 p r a n t of tbc moiaarrr d be IcIL)(Ned rad cadenrcd of air bar is 6nd in 3. Airkkap. A vay canwa into water. Sinee WKCX is buvi cbm air, it aill seck the tlw disaibutioo system w h m . duc (0 6cuoIuI UmpaDm low.Stpoin1 radhrc U this point. i m p is insulled. If. h g s , thc awming ud Eoolingof heswill d t in btmp is n a 4 , wwer will colla in the baurm of the air age U vuiols linings ud .xmMkas. 0 t h c r C " b u ~ to rrcciva. lir !us uc WmI out quick duage dirmDea couplerr. l a k IfM .freMolermubc lncd ud ifthedimibution lioa ing nlver m air dcvica. open nlvcr (uon drop legs or uc!tmg enough todlw me l i r to cool before a i used. dnia lines). d i m p p a use of air (annc). ~ICU itlla i t the far cod of the air spurn would k the next Leakage in the distribution system can k chccked by tbc bar thing. l l i s film should h m an rbrorbcnt dement .nd c o m " method of %aping''. A soapy ~olutionapplied pmvisions to d a t the w.3 It the ln"of the dcvict. with a brush to each pit wiu indiucc *rha or Do( mu 2. oil joint is tight. Rognmmed maintcnlnce of air devices to Anulm oyy ofmis the prrrcaoc of oil in the rtplacc worn scats. cw.. rad to rtphcc faulty discollnur ryaun. Grmally,lir mnpiw i l l hnr I aruin m u o l couplers will pmrc to be the mort eMnanical sdutim. Air of oil vaporprrscnt in the discharge air. This is the surplus oil is nu k.A small. continuow leak, say a hole .bout 1116' c h s t i s ~ w i p c d n n fmnlhc y cylindawbythepism dim=UD cmt Ihe l ~515.00 f ~IO 530.00 p r m t h . Reringr udis urricd into me air s "LT Oil npor-the high vcntive maintenance is less upnsive. tempmnvc in the cylindcruiuing the of oil. As 4. Misuse. By misuse we mean waste. A worker will use his the oil "par cadchccs. it canbina with the m i m thnt is dusting gun IO d m off his dotha or cool himself in the plcsmtto lorm amilk-like liquid. One dropof oil uo m a n sumMlTiM or to dust the floorinsrpdof nveeping it with 1 Mof appmxinutdy 9 square feet of Ipan of wucr-idb". Anaherca~lar~ o u m of mte is on thc dnin line athe c m m when a pisum type canprssor\rurrbout OT drop leg whcrc the d v r Ius been *cracked" to permit ax 4uu( of oil forerery 4,000.oa)CUbK fcuof air it pumps. constant draining of condensed water. 7 h e remedies for This oil when used in 1 rprny gun will mix with CoDting m u these arc obvious: Improved supervisory conlrol of emd s d caw f i s h failpbycs, r c d of surplus airirdcvica when nu in uy ud Oil is much morc difficult to r e m m than water since oil provision of an rutomatic dump n l v c IO control the diswill with the rir nw. oil ~ l be l l ~movedonlywith PD charge of mdenvd tntcr. rbrorbmt type fkr. Passii rir thrwgh UI.bsorknl hlur will r c m m the oil; when h e filter dement bccoms satu9. Contwnlmtlon. Amha common diffidty caearnlcrrd Ned. it must be rrplafcd. in Oanprrvcd SysUmS CCQMMhI Of air k. s h , .. An lftcrcoda will mp 1d .mount of mc oil SeepiW imotbc rynrmin iu nonlul O p n I i a I . utbc -is bkily Wml and l n acariK lmountof oil is rwDdinIk air lyncm. me prill ccasI8nlIy k dunging Blurr Thir unit is c 0 " C n l y d C d M 'd-punPr" ld thc P m p a d Y is Alnyr operate immor U the highesI volugc possible. Man lqa thrn 1.5 h.p. rbovld pefcnbly k operated mchreeplluc u cbe inidarn, aswellu openting a t . will be higher tor single phzce mdor acecdrng 1.5 h.p. kwrcnm cbc maor is UMmCd lothe pmpr*duge and toovahulthc~. Ijnc phnc u spccif~edm the mdor l u w p l t e . 3. Din 6. W b c n ~ uan extension cord is rrquirrd. use me having QD bc very crrily rcmorsd with iproper 6lta m tbc the proper sire wire in relacioo to its length IO ~ssmit wmprrvor inkt port. M M y fitcn arc nailable. the most willcclrrythekd. common k i n g the screen ryp.This ryp has nu pmKd 1. Alwryr fuse 1 comprrvort el& iupply. nryeffectivck u u c e it is M* king wed pmpaly. fi is sup 8. Be crmia rhu the dcctrk supply is upable of handling "bcdippdinoiltogivethcrreear'~"t0 the canprruort electrical load. R C m any aher elccarcb the dinpm*les astheypystJuough. H a m u few triul equipment that m y k on the same circuit. will maintain this 6lrnin chis and. therrfo~.it is 9. Running M air c w p m r o r i t iphigher than i u seldom used.Ibe majority of ierullacioos will pmvide m rued capability will l o m the air volume output, cause oil bifh type of filter i t the intake port; the air passes a d d i t i d %tar, and rhorim the life of the quipmen:. h g h the oil oronrthc oil. tberrbyremoving the dusIor 10. Chcck "load heater elements in magnetic motor SURdin pracnt in the inwdng air. ?hir is LD effecrive means crs. Hater elements i r e ilwdys stamped with ampere brdin ud dust Kmoupl. Among ahercypcS Of din @IUS ratings. These should read Ippmximtdy 5 to 15 prcent mailable, the felt ryp is wd in many insrallstimr Local higher than the full load rating of motor a1 operating cadiwill dLure thc typc most suirable fa chc pmicuvoltage. This full load rating is sumped on the motor kr inrullatios. nameplate ad is also indicated in amperes. Too high a VIII. GENERAL NOTES cuing of heater elements giver no praedon. Too low a 1. Alwnys fill a new air comprasan ifrrquired. with nudvd rating c a w stanex 10 Chmarout during surting periods iufomariVe omdetergent oil having the proper W E weight or in ha -Iller. or the special oil which has been formulated for air c a p 11. The air rrccivcr should k LD A.S.M.E.cmihed wsscl. prcyorr. (See low oil prryurr item la, Page 12.) This means rhu it carria ilabel cmiryi rhu it is con2. Keep air ccinplcyorrc far iwy u possible hun the paintm u d in accord with the A.S.M.E. (A" Society ing M. of Mcduniul Enginem) mde lorunfued prasurc wsscls. 3. air infs.h fitels dean u 9 times. If tbc row cmuips Most nrrccodarqui~~ periDdic bydroswjc cstingto see ihavy cmccnmtion of dust OT has ihigh humidity, pLec thu tbc tlnlu continue t oc "to code rquinmcnts thc air intake outside. If limg pipe ~ l l uc s midabk. i Altemtimr nudt to thc air receiver in .ny manner will d e of thumb is to inncrse the size of tbc pip in the Nn indidate the A.S.M.E.cmifiuu a i d m y violate loul one pipe size for each eight foa length or tun. h i d e i cods .od lffea me plantr io5llnnce cwmgc. large enough Nter ud a wcllha shield for Moutside intaLr 12. c h c ~ k d i " of rotacioo. Mok air comprcrpon indicate 4. If the comprtsor is not q u i p p d with iloadleu suning dirrcdm O f r0Ufh byM -a &he)' Whccl OTConmechanism, do not stan the ccinprc+ror against i,badrult tbe manufacturer's compmror inslallrtion manual. 6rsh remove 111 air from the system. N O k somUnitsrmyopaucin my direnim. 5 . Form el& moor drivcn camp-, the voltage, a m p 12r.laar oil prrravc UII k caused by OM of UX following: age and proper phasc ~ l ~must n bet known ud milable to (a,) No oil. operate the elecuic mmor. The follovring m y be of ym @.)Wrong direction of mtition of the compressor k i p io detemrining the proper kngth of extenrim ond for Ry-VM.. . rrmll pomble el& comprcssorr: k. ) oil pump. 314 b.p.. l l S volts. single phue q u i m 10 amps while 13. Discharge piping must k adequately sized and installed w) operating ud a No. 14 cord lor SO h. u to sbpe away or Mnrd the comph+m. Drains should 1 h.p.. 1 1 5 v o l ~ . s i n g l c p h a x ~ u i r c s 1 5 u n p r w v h i l c o ~ be pmVided u low poinu in cbc system. uing ud a No. 12 cord lor SO h. I k exercised in using pmablc (hand carried) 14. C . u h is O 1.5 b.p.. 1 IS volw. single phase q u i m 20 amps while cornThey haw iundcncy to 'wplk" or crap. operating and iNo. 10 cord for 50 fi. when in operahn and care should k u k c n in their placeNote: Suning cumnt draw can be thrrt tima u high rc men:. In 111 insunas. it is rcfanmerded thnt the unit k the operating current. and fuse pmcctian should k i recurdy anchored. especially if placed in overhead locaminimum of two md one-half times the operating tions LW a r k damage is porsible if the unit should crccp. currcnt, whenwr possible. 15. buIl a sewer dmin in h e heon of icomprasor 100m for A rule of thumb for calculating the ippmximrtc the r e m d of cordenred water from the air receiver or c u m n t consumption of i n clenric motor for a& lfummia. boryxnvcr of energy dcliwrrd: 16. Rcrd all iamuaionr pcruining to the air ccunpraror and 1.h.p.. 110 volts. single phase q u h 12.8 amps. cbe related equipment kfon openring UX unit. Additianal 1 h.p.. 220 vdw. single p b q u h 6.4 unps. lnfonmptian can be obtlincd hunthe quipment manufac1 h.p., 220 vdu. thrrt phase q u i r e s 3.2 amps. turers. For information on the installation and trouble shooting of Bink's air cmprators. see Pan Sheet 1767. 1 h.p.. 440 vdu. three p h w q u i r e s 1.6 amps. 62 QSan.’Ibc kl&tb atering a “praxnvill ”h.o mersarivruurrnd pcm” puu rrplromau. dcrreueeffianry, daaiome litdnirarrd in UIQ Iucb as Gnihing. dfathe quality ofthe bairb. ff MI is pamc in t k disdurged air, it Mutes thu the pips or r e a h LII: mud. nbt rc” in the sysum a unit has been ind c d ul8t is Cmmuaed of incomcc “ i l l . IX. THERMAL CONDITIONING AND PURIFICATION EOUIPMENT A. 0.n” *removal of m0-u fmmarmprevpd airh imprmnc in the inlclcst of dery and pmccnion agliart dunrge to lit rods. “ials.rrd pmauac. ll is impatsnt Ihu Callprsai air be d c d . dried. and d d b e h it is disaibuud for we 1. m e n lir is compressed it becomes very ha, ud in chis uulitim. it is a paentid expbsi. Danger of a Callbustion explosion. in either the air receiver or pipe liner, is always present if the air is not sufficiently cooled after laving the comprrssor. Heated air will result in less air k i n g s t d in the nceivcr. hold more water and cause the pipe lines to expand with subsequent conmion when the compressor i t shut down and the pipes cool. This cooling will cause condensation and the dtcrnate lengthening of tbe lines ultimarncly produca leaky pis. 2. The air in the atmosphere is ncvcr rully dry. Water in a vaporized condition is dwayi p m n t . the mount b e h d e n s a t i o n occurs is in d k a proportion to the tempennuc of the air and inwscly pmp”lo the presswe In ocher words, the haur the air. the more moisMc it Mhold in vapor form the greater the presure. the I C 0 anrcrwpor it can hold. A change in either praurc or tempenlure up sets the equilibrium of water vapor hlled air. If the air pssure i n c m c r and the temperature remains consunt. air bws i s ability to hold water and cadensation ulra pLcr This is the procus which awes nin. orwaur rcumutrtiaa in air roceiven. pipes, rrd wur a Corn+ air k o m s s d a as it lpprorha the cnd of the b e In cooling. it baa i s capability forwrying moisrum in vapor form lad thereby tbc m o i s m it cmdenstd md discharged in liquid form (water). Sudden expamica of compressed air at the point of dischuge c a w rapid.(iring). The water vapor in the air is thcn funher cmdcnsd nnd carried through the air dcvicc and discharged inq Ihe armospherc. or in many i n s m a dischqed mto the wrk or process k i n g p!”cd. In pneunuticdly openledmachhes. lhis Idcase of w.1cT rem o m lubricating oil m l t i n g in equipment irvfficicncy and deuriwption. It may cause excarive 115u m nlm, faulty opention of air contmlled quipment, rust. -km, finish failure and if thm is a possibility of lim: f“g,the Ycumulation of w t e r in b w points in the distribution system may wlr in bursted pips. 3. Vapori2cd oil can present operating and maintenance prob. Icms. Too high a temperature and excessive oil npor in 1 critical mixture with air can mu11in a combustism upk lion. Adherence to safety prncedurrs nnd proper mainrem c c of control quipment is panmount. Oil should be removed beforc it enten the distribudan system;c n a then it will creep through and most likely cmlnminnte the prcduct or pmcas. Oil is inuoduced into the air supply because of compressor w a r or i a high operating temperature. Note: ’IXs problem is ncf present in the oil-lss typ corny. 4. If rdid plnjdcs or aher impurities, such as rust. dust. dwnt vapors, overspray, etc. are present in che immediate a m p h m . t h e may be drnwn thmugh the canpressor ip takes and find their way into the air distribution 8. Aflercoolan The primary consideration is to nduce the tcmperaNre of c o m p d air. Hut.as well as m e impurities. u11 be a&by ins~allingan lftafmler in the system. Aftercoders arc very efficient in bwering air temperature and removing mt of the oil ud w m w . the residue of oil and waur slill be rcmowd before it enters the air receiver. There arc several different designs or typa of aftercoolen mailable. The most common is the water-cooled “air tube” design in which air pasts bough s d l Nba rrd rc-eireularing water is dirracd back and fonh moss the rubes by 0fbPwc-s and moves in a direction counter to the flow of lit.This cross-flwprinciple is acccpled Y the most efficient means of k~ apnsfer. The air is cooled to within IS’ of the incoming city water temperature. using approximately 1‘h gallons of water Tor each 100 cubit feet nf compressed air passing through the unit. For example. on a 5 h.p. unit with I9 cubic feet capacity. a cooler would w I H gdlms of water for each 5 minutes that the compressor was actually pumping. The water flow is controlled by a solenoid operated water controlled valve which operates only when the canprrtror is “ing.If the comprersor is opcnting with 8 consIan1 specd unbader. then an air operated water control should be installed. Oil nnd wmter leave the lhmoolcr in a liquid state. king condensed by c&#. Ir is either dLened to flow back into the air miver or tn a moisture ud oil rcp.ntor which can be l U t c a U t i u l l y or rmalully dnincd. ’Ibe afurcmlnis an ascntid ppn o r a CDmpletc and pmprly functioaing ccinprrswd air supply system.The larger the air compra~orand the higher the operating prcyurr. the greater the need for an Iftmmla. 1. Cmsihtion in vkaing afummlm arc: a. lhc m i m u m volume of air the lftncmlnmust hmdle. b. 7bc m i m u m working prcyun of the aftercoder. c. The required temperature drop for the compressed air WPplY. d. The milability of an incoming cold water supply and its tempenlure. e. The sire of the pipe connections at the aftercooler for thc inlet and outlet of bah air and water supply. f. The mans for removing c a d e n s d oil pnd waur from .the system. f WATER OUT . WARM AIR IN - f Water-cooled aftercooler 63 WATERIN C. Automatic Dump Trap This mp, iorulled u Q bwspoint bclw Iheailrraive. will d l e a cordcnvd moisture. I! is 10 designed t h u k mp opcns automatically IO discbarge a predetermined volume. Due to the air pnrauc kbind the pntcr. the mp opens and doses with a snapaction that insures proper rU&g Of the dosing valve. A s d line mrina should k insulled lhud of any automatic device to keep loreign particles from dogging tbe working purr. If this unit is properly .iasulled. with a line smincr. it d l giw long and satisfactory service wivith minimum rmintenancc. D. Air Dryen Good Iftcrcoolm will r e m m the greatest percenmgc of pntcr vapor but the midue can nil1 caw problems. For example, if 10 cubic fon of free air holds I a.of water pr cubic foot and this volume is compressed into 1 cubic foot. at a higher pressure and temperature the moisture that YN in the IO cubic feet will k ccntlined in Q I cubic loa d u m in the form of w e r vapor IS long as the temperature remains cleated. When the air cools down to i u original incoming temperature (into the compressor), a11 the water vapor will condense except for that amount lhnt was in the original cubic loa volume of free air. This will condense out vrmnrherc in your distribution system or k carried inIo your air tools or finished product. There are many designs of air drym milable: among there the most common are chemical. desiccant and refri&ntion types. All dryers arc designed 10 r e m m mOiSNrC from the compressed air supply 10 that no condensation will ulre pl.cc in the distribution system d e r m a l ororking eoaditions. 1. chemical Dryar (deliquesanc. dcbydnIor typ) Chemical drymopemem h e principle chntaminchemh i s d l ma with moisnuc. forming a d u t i m tvhicb will dnin Io rhe baum of chc dryer and krrmowd. The &m- a sused in the o p e ” have Io k replaced IS they M consumed in the process. The chemical can be salt or a specially lormulaled material. a soluble chemical desiccant which is more efficient than salt and is non-comive and Don-toxic. Most u r dryers “scrub” the air h e times: Fmt, by the mechanical separator; second, by the misting system; and third, by the soluble chemical desiccant. The plh that air b l w bough a chemical dryu is Y follows: a. Mechanically-the entering air s t r u m parwr through II d e wbich atanircc the mOiSNrC drippings from the desiccant chamber. The air strum is then merscd in direction. causing condensation (free water) to be thrown dear. collecting in the bonom of the unit for autormtic OI rrrmlul discharge. Daicuat min prc-dria the air. h p l e u from the dericcant bed are a mild chemical solution, created by moisture vapors slowly dissolving the desiccant beads. AtomiUtion of tbe dropleu by the entcring air strrun creates a bg-lik m i x ~ r e a, c h panicle uill retaining an affinity lor moisture. This rrsulu in about 60% of mc pntcrnporbeiig RmOved prior I o t h e air ”’r contact with the desiccant bed. minimizing the usage of . ,the n w daiccant buds. AIR SUPPLY LINE NORMAL INSTALLATIONWITH AFTERCOOLER Desiccant dryer U 3. Rcfrigmaim Air Dryen Amtfhaovnl ' refrigeration system soolr Ihe h a t exchanger by chilling the air to itemperature klmw the minimum tempen- hu is utainablc in tbe disaibutim system. As hmg u the temperature in the system remains above the dryaqlqmuwe. the Smditiarr fortbe b l m a h of a- dcnuticm & na &. ";'," -f= 1 9 - AIR OUT Refrigerated dryer 4. Ddiqucrcnl Dryen The deliquescent type dryer removes moisture from the ~omprrrredairthro~gh mcm~.l-. 'ibe a i r n w uuuugh a cmlaincr of memiul pll*s u sbwn Q F W 8. As Ibe moisture (liquid ud npor) in the lilcmuN meJe pcllcu it comb- with (be @let dmming irolutim in the boaom of -the auiner. This rduticm mwt be dnimd rany m a periodic basii Also. siaa the water divdva the chemical it must be replaced periodically. Deliquescent dryers cm hudle my Lrge airvdumes but M uw.lly lerr ~ & U d r y i i a i r ~ a b m ofdrym ~ Deliquescent dryer 5. tiDcFJmaOildWatcrExuufors A line 6Iur is to be insulled at any point in the dirmbutiw Boa where air must be dry and oil-fm. This is “ d a t o r y if a comprrrred air system is used wifhout M rhnsodu. The best typ line iilter is the absorbent type where air plsa through an element of YIW marerial that will absorb water rad oil panida. Remember t h t water always seeks a lmv point. whoil putides uc urried vith tbe air. Some oil and water extractors are combination filtcrregulators Ud UT convenient where prryurr rephion is necnsary:Wherc pressure regulation is no1 necessary, main liDe c x m c t m ut nu only sufficient. but better than moIt line bltm. n e prirmry tra5on f w t b i s is &I oil rad water cxuaam are made of nonconusive maccrials rad (heir Life exceeds that of my steel or irm arm lbese Oil Ud water CXUaC(016 1TC baled in the dirm b u h system rhcr the air wivn.Tbc proper disma should be at lust 25 feet w a y from the air receiver so that the air bar a chance to cool down sufficiently before d i n g the UmCWI. TbV UC M e f f h UlCaIlS for ICm o d of impurities n o d l y found in the majority of air distribution systems. An extractor’s efficiency is wriable rad is rclarcd to the t e m p r a m lad humidity of the compressed air. These units do not provide results as CffCUbdY air dryers, h-r. the& lower hitill C a t is a factor m sclectioa of alternative mum. One unit ail1 be required u ucb &-off point on fhe main line (header). a. Oil a d water extractors must be drained daily. under pres”.to remove impurities. If the umditims are exmmely m.h e y may have to be h i d periodically duringibedly b. Extractors having filters must be disassembled and Ibc 6lter e l e m i dcpned or -la&, otherwise the mount of air passing through the unit 4 1 be appreciably dud. c. Maintenance schedules should be establishedlo.clcan. dnin Ud @iUX frlICK U.pCriodic h l C d S . d. 1! is good pnniee to keep apue air s a l s for oil d wam c x m o r s on had. * 0p.ntiar: The rollo%kgbriefly dcrcriks OperUioDll ch.nacn’SliCS of Common rypa of’exernon: 1. m e pLter uc used to forn Ihe lir “S toch.nge dinaiaD very rapidly causing the bmviu din panides to be dislodged and carried h g the side d s to the bottom of the extractor. Others incorporate a lead screw principle which creates a cydonic effea or a whirlwind rype of air mowment. This muion causes the havier p a n i d a IO be dislodged against the inside 4 1 s of the unit. b. Another method is IO hive the air strike the cooler 4 1 s of the umaor’r oum body. This in cmbmcioa wiIb Ibe pressure drop resulting from air being used will -use water to condense out of the air. c. Filters are employed to trap solid psrtides u well as absorb moisturt. Some of the different rypa of &ICK available uc: -prous OI S i n t ~ bd m -metal or plastic cylinders -high abrorbent dah -water absorbent chemicals Selectlon Conrlderatlonr: be required to dean. b. Maxiium working prcssure on the umaor. c. Method of filtration and water extraction. d. Piping inlet and outlet size. e. Distance for Ibc compressor to the extractor. Note the minimum recommended distance is 25 feet. The piping should slop towsrd the ccmpmsor lor best m l u . a. Volume of rir bot the e x m n a uill W E. Flltera m normally a mechanical means by which solid partides ue reu.wed fmm che air supply. Filter uniu normally do od re”c moimvc as it is a watu npot (gaseous) form ud will pass through with the air swam. The principle function of a iilter is to remove he solid parades out of the rir smam t h t may cause a malfunction of an air device or may damage the equipment. 1. Selcnion Considerations: a. The vdume of air required to flow through. h. The maximum working prrsrurr. c. Met Ud outlet piping sue. Nlen d. Materials of consmction-corrosim mistmt. ctc. e. Si of film clement-this will determine how often it hs to be dcancd or rcplaccd. 1. The smallest size panidc it will filter out (retain). 2. Mvlouges: a. Will filter out solids to a fine degree depending o? w r e n mesh selected. b. LWI cost. E. Easy maintenance. 3. timitntions: a. Element must be d u n c d as conditions require, otherwise efficiency Ud rir flow will decnaw. MalnteMnce: T h e following are yrrognm: . _ the requirements of a baric maintenance 66 COALESCERS,AND AIR DRYERS Ty#uL OIL L WUER CONDmOW MDlWToR H W 8H W RnAINER - lV8E DESICCANT CWLl8ER TlE ROD R*lE FILTER INSPECTION WINDOW TUBE n EROD RETAINER RETAINER SEN NUT SEAL STEM ExTRAclvR DRYER COALESCER X AIR REGULATORS 8. Qw Air rcgulatocs uc desi& in NO diffcrmt wks The ”nL.l ppnr of each uc the YIDC, the diffpcnce b e i in the m y cbc body has beell drilled. Ih 6rst ud mod1 fo”Bl style is referred to as a standard regulator. Swdnrd regulators are d y uud m oil and vnur exaactor reguhor crmbinaticms ora9 tbc Iccad re&” 1 prcsult unk. Ihe wmd style is r e f d to LI a by-pss ~ g U hwhich t ~ has U U h h C pnSW O rCguhrcd MltlCL5 md 8 b y - p for m.By-prsr regulators uc wully nnployed LI the hnt regulator m prrra~lank. when manifolding regulatm tqcthcr or even used as uke-offs from main air supply lines. Bypass regulators may be identified by i n d u c i n g air into the inlet pons msrlred ud observing if& air p”res h u g h wihut lirregulntion laking *. A General Dmerlptlon An air regulator is 1 l r l e d m . d deviccwh*hrrhmsthcuniLl line airpresavcto a rpdficopcntingprasuc. ODfe thcopaathg prcrauc is set. the regulator will autanariully cain this setdng. For a m p l e : if a IO0 psi main liac supply of air is to k reduced to .D operating prcsurc of 40 psi. then the air regulator wiU h.K to k yi u)m u a 60 psi dmp inthc syum. If the IO0 psi supply changa. the regulator will wtunati. ully canpensau br this change. Once the regutatom .IC yi. any reduaim in prrsnvc will cpuv the reguluor to pro mole lir. if the pincreases. the regulator will pro Ius air. ’Ibe prrsnvc set in thc regulator will dways be consun1 Lrrspaive of the main BK Euctualioo. A regulator will NEVER pmvide higher air pressure than the air distribution system has to offer. The fdlowing dewrib the sequence of operatiom -ty turning the conml knob in a dockwise dimtion, the tollml knob screw will push a button. -the buaon p u s h against the regulating spring @re-baded). -the valve sum, in Nm. moves the valve away fmn its sea. -air e m ty thc seat into the regulated outlet. -air pressure an the regulated side increases, this prruurc p u s h against the diaphragm and regulating spring. -when the air m Ihe regulated side is balanced, it then against the diaphragm and regulating spring causing the vPtvctorenua to its seat (dosed). -as air is consumed from the regulated side, the mulunt pnxwc drop will m u an unbalance of folra (air pnsurc) against the diaphragm and thc spring caming the valve to unseat ud. again. pas that mount of air needed to balance the m u m . C. Selection Condderrtlon 1. the d lor a standard or by-pas ngulator. 2. thc volume of air the regulator will k q u i n d to handle. Nota: to &de Ior future necdr. always relea a regulator ltaving a capacity about 125% of your c m n t determined volume, 3. IIIChighest operating phcarrr the regulator mun conml. 4. the propcr size of gauge required lor the regulator. S. thc sire of pipe c ” of inleu and outlctr. D. Trouble ShootlIq 1. scc pall sheet pertaining to pur specific regullor. 61 2. Robkm: airlcrLzan of hde in rop of -. kmcdy: tighten lc~cln m bo~uwtEmpc. %J. AIR LINE LUBRICATORS If his doa w( stop the l u k . it is likely that the diiphngm his been p”d. 3. Roblem: regulator grugc dimbs In rmin line preram. Rcmcdy: duo m .od stem or npLcc with new puu. 4. Roblem: regukor will DO( rephte pre” Rcmcdy: spring returning the n l v e stem is rusted or V r l ~ sum is held fast by c o m i o o ; duo puls a f f d or repl.ce u qltired. 5. Roblem: regulator rinp or h u m Rcwdy: tighten scews m bonnei tlmgc, rcpLct Bukecm 1 l e c d g=k: m tbe d e r si& of the di.Pbgm. 6. h b l e m : no air p i n g thmugh regu1oM. Rcmcdy: mrkc sure ail supply is ”d m; check Io ree if rir passer k l y through oil d water eamctw, ICC Uut air is ruching the air regulator; inspect regulitor filter screen: dun 111 air passageways in regulator; replace or dean regulator fiur m n if required. A. Genom1 D08crlptlm The dctrimenul effect of oil in an rir line system bas been arcscd rcpcplcdly thmughout this Tniniag Bulletin. H Qrr are inswhen iproper mount of oil d y atomLcd is essential IO the opentim of anaio rypcs of rir cools or air openud devices. huuduaica of this aMtid lubricant prrm t s sorrosica. sizing of Qse tolcrure taring surfaces. .nd main& the rcrfiCacC O f ’0” IiUgS d vrlc hthirpurpac lubricuon CM be mound mora the oprrrtipgdevicc. built into the device (many a i r i r s hrvc this f a m),mbeinrulledin C& airmtunjmuprr” of I& inler U, thc rir cod. ODKiubricnton in~ulicddthe propr M of lubsiutico is rmiouirud. they will pDvide autwaric l u U m u, equipment. - SIGHT DOME 8. S.leclion Conddomtlon 1.cuprrquindTormCippliacioo. 2. dumcofairtheunitmustp.’ 3. .mwllt Of hbIiCM1 R@d. 4. VOrLing praaue of the unit. 5. pipe inlet lad ouuu sia. 6. quantity of oil in the lubriutort rrscrvoir. 7. cup of lubrimlt quid. DUPCIIUQY OASKET C. Adv8nt.90~ I . UK cquipawnt quiring ilubricant will rscivc the corIUXl”t.ndcyp. 2.minimitarOdrrp.ir. 3. beau qmat@ efficiency. 4. rods and d e r air opentd dcvim my be stored and slbsequeally urcd without cmccm IS OI oil sludge being crcaudinmetod. 5. 1ubric.n~i r e fed into the tquipmcnt d y when unit is oparting. D.Llmit8tbl8 1. it is iddilionnl piece of equipment that q u i r e s mainIeNna. 2. ddr diffmnr weiglu oils IO spxific typr of air opcraud irr 3. nu dI rypa of lubriunt uI1 be uwd. 4. mervoirs may require hrqucnt filing when lubricant requirements uc high. E. PlOC8UtlOMry NO108 1. Using imuM-tool lubrkator thm is dways the danger thlt me unit mly nul dry .nd damage to the tods using Ihc same system. Lubricating-maintcnmcc of the oil kvcl in such insmcs-is of primc mccm. 2. Keep air lines short; oil sludge my rccumulale in low rpau of bng rir Lms. N R REGULATOR 68 3. S k rypr of lubriunt rbould DO( be used u cbse oils will create paint drrishing problems. ochn rypc of lubria n t s arcb as mdy-graphite. sewing MchiDe or 3-io-1 oil Cmuio ldditives wtlicil m y h g e crmin tyF6 of vrlr and surfaces. It is recommended that a sundard noa&lagent automotive oil or the special oil *pod (or lir mam k &. 4. To function properly. lubricators mu1 be matched to the aluipmcntt o&dr 5. Thc propcr.mount oflubricant is imporuntrrux) much LI *rll u ux)little ullcrcote pmblemc. A good d e is toadjust the lubricant feed until a small of oil is prccpiblc u the & u t pon of the cod. An -supply of.oil bas a teodcncy to create an "oil fog" which can k objcuiauble to popre wrking in dose proximity. amainof the rrpnsica *'ro lir". d i n this TDBUllctirr t h e " m s a i r 8 t the rtmorpherk cadiuolu u me point W h the canplum is iatcnlled. HORIZONTAL COMPRESSORS have the compressing clement in a boriznnul p h . INTERCOOLERS uc dnica for rcmwing the heat of canF b Of the & M PPI UmsCfvbVC SURM Of mUlUnrgccanprraon. LOAD FACTOR is the nfioforthe m g e ccinprruor output - ."eht LOW PRESSUREORIFICE E S T is a method of sccuntelv meawing the air delivered by a compmsm. It is the me& the CanprrVed hUNte. MECHANICAL EFFICIENCY is the ratio of the indicated boncpwer in the ccmprcsing cylirdm to the indicated honepwr in the pawrcylinders, in the case of ncun driven or intcmal combuticn engine driven fanprcsson and to the brcak horsepower delivered to the rhaf! in case of a paver driven machine. II is cxpmscd in per cent. MOISTURE SEPARATORS arc devices for collecting and rcmovinp moisnvc . precipitated hthe air or ~ a durine c the . proeas Of cooling. MULTI-STAGES COMPRESSORS PR those in which canpressim from initial to hal prcrauc is completed in two or mon d i i n a steps or stages. NORMAL AIR has ken vuiouslydcfinod.In this bmk the tcrm rcfm to air with a 36% rdabVC humidity u 689.This may be mLtidned an " a g e d t i m of the . r" in I tempnte ctimuc 'Ibe &of spedfic hm~5OT 'n" is I.3947fornonnd air. Density is .075 Ibslf~.'u14.7 k d m ? d 689. OVERALL EFFICIENCY is the prcdw of rhc comprcrrioo ' 11 efficiency. efficiency and the lncchNc PORTABLE COMPRESSORS ue hosi in which cach e m prarina element consists of a oistca movinn back and fonh in i cy&. ROTARY COMPRESSORS uc Ihose having a m e mor or its cquivllent mounted eccenuicm in a s & q cuing. SINGLE-ACTING COMPRESSORS are those in which com~rrrtionuka olpce m but one smkc cer rcvdution in erch rompressing element. SINGLE STAGE COMPRESSORS uc thorc in which comprrsrim frrm initial to final prrrarre is canpleu in a single step or stage. TWO STAGE COMPRESSORS arc those in which compression from initial to final prcrwve is completed in IWO distirm stcpr or suges. VALVES ate clasribed in two distinct types. Mechanically operated valves depend for their opening and dosing on "e u d ,~ ~ ~ ~ c h v means. l i c a l They uc usually driven fmm the mnk shaf~.Their time of opning and dosing is fixed in etariOn to the mwement of the piston. Autaralic valves depend for .their opening and dosing entidy on p ~ a a r r diffcrcnca. c In the CLY of the inlet valve. b e t w e n inukc ud cylinder p r e s " and in the case of the discharge valy, ktwcen cylinder and discharge prcsaya. VERTICAL COMPRESSORS haw the ~ n m c -~element i n ~ iuavmjcdpIMc. VOLUMETRIC EFFICIENCY is the ratio of the actual capacity of the compmror to displacement ud is expressed in per cent. rrcognized XII. GLOSSARY OFTERMS FOR COMPRESSEDAIR SUPPLY SYSTEM ABSOLUTE PRESSURE is the existing atmospheric gauge pre~aue: plu atmospheric p""rc. At vp I d thc gauge pras m in pounds per squue inch plus 14.7 psi gives the abwluu' preJaue: in pounds per square inch. ACTUAL CAPACITY of an air or gas compressor is the quantity of air or gns comprcrrcd and delivered. II is vsually expressed in cubic feci per minute (CFM) at intake pmsvrc and tempemure. AFTERCOOLERS ue dfor rcmaving thc h u t of can. prcsia~of the air M gas afur ccmprcssion is rompletcd. They ue me of the mest effcujvc m r a s of mnwingmoisnuc from canprcycd air. AIR RECEIVERS ue unks into which eclmprsed air M gu is discharged for the compressor. Receivers help eliminate F u h i a l s in the dischlrge line ud also m u rrongc capacity during intcrvrlr when the d e d Rfeeb the upldry of the - - crmplaun. COMPRESSORS ue machines designed br rompresing lir or gas from an initial intake pmsurc to a higher discharge P===. COMPRESSION EFFICIENCY is the ntio of tbe theorcciul horvplmto the larul indicated h o n e p w r q u i d to canpress a dc6nite mount of gas. The thcorctiul pwr m y k cdculated according to the isothermal base or tbe adiabatic base ud the compccssion efficiency comspoldingly dchncd and up& in per cent. DISPLACEMENT OF A COMPRESSOR CYLINDER is che volume swept through by the piston. aillh proper deduction for the pistm rod. This is w a l l y c x p d in cubic feet per minute. DISPLACEMENT OF A MULTI-STAGE COMPRESSOR is that of the h n t stage only. since the same gns passes through dl stage in wria. DOUBLE ACTING COMPRESSORS arc t h a e in which crmprruia~ULeS place m buh smlrer per moluriOn in a h canprasing element. FREE AIR is air at normal atmospheric conditions. Becaw the alti~de.barometer and tempennrrc vuy at different localities md i t different times. it follows that this term docs not mean air under identical caditicas. Considerable c d m hns existed icganiing the l ~ r m 'iiu air" and it hs o h k e n interprcted to k air at sea I d condirjans. namely at absolute p~sslrc of 14.7 psi and u a tempnturc of 689.This is na the 69 - ~ HOWMuch Does An Air Leak 1/64 .36 HP .09 1/32 1.47 .37 .30 .38 8.23 98.76 0 3/64 3.28 .82 .66 .85 18.42 221.oo 0 1/16 5.87 1.47 1.18 1.51 32.72 393.00 0 3/32 13.10 3.28 2.62 3.35 72.58 871.OO 0 118 25.80 6.45 5.16 6.60 143.00 1716.00 03/16 58.30 14.58 11.66 14.92 323.00 3876.00 103.00 25.75 20.68 26.47 574.00 6888.00 LEAK 2 $/MONTH Cost ? 0114 SCFM KWH $/DAY .07 .09 1.95 23.40 I $/YEAR Based on 90 P.S.I., $.OB per KWH, 2-8 hour shifts, 5 days per week. An arbitrary cos1which varies with time 6 place. -< Material Supply THE SPRAYING SYSTEM A spraying system is an inter-related urembly ( ip ment that contains, conveys, and sprays liquid material; and which includes all of the control apparatus for operating this equipment. ' h e material supply portion ofa spraying system consists of the container. the agitator, the pump, and the auxiliary components that filter and regulate flow of the driving medium (compressed air) and of the driven medium (liquid material). 'his bulletin describes the material supply equipment and discusses their use. operation, and maintenance. 1. METHOOS OF FEEDING MATERIAL TO THE SPRAY GUN Rint spraying systemi axe either gravity. riphon. or pressure fed. A GRAVITY FEED Gravity reed preceded the present, and now more widely uud. pressure feed method of nuterLl delivery to the spny gun. ' h e main r q u h m e n t of gnnvity feed L that the container be vented so that atmospheric air cu~.re. p l w the material u i t is being spnyad. The gravity feed equipment is relatively inexpensive in Initial cost and in operation. The container can be refdled without interrupting the spraying operation because it is at atmospheric pressure. Howenr. this method does have some limitations. Viscosity and flow characteristics of the material directly affect rate of flow to the gun: s does how sire and how length. Row is also affected by changes in pressure head which will vary with vertical position of the gun and with material in the container. The container may be of any convenient size with 2 gallons most common. Its location should suit the materkl supply requirementr of the gun, Wdng into account that resistance to materid flowincreases with length of hose and with additional valves and fittings. Its location should also mate Nling convenient The container materid should be compatible with the contents. to avoid corrosion and chemical reaction. It should be lidded and the Hd should have a vent bole. E. SIPHON FEE0 Siphon feed can be wed only with an air spray gun: and only with a gun in which the material is atomized outside the n o d e of the gun (in some guns atomization is internal). This is because in the siphon feed gun the siphon type"external &"air nozzle (we Fig. I ) rends a hollow column of moving air around the fluid nozzle and in so doing draws material out of the siphon cup. ." >.... *..& ' . . < ?he siphon feed s p n y p n E O h w t s of a hand heid cup and p n ruambly that h used 8s a single unit. Since it h held in one hand by the opentar. Its weight, Including liquid material, has to be limited. Cup sizes nnge fmm 1 qt. capacity (maximum), for gencnl spraying, down to about 114 ounce (minimum) tor air brush applications. Siphon feed spny guns usually operate at 30 to 60 psi. Fluid material flow is controlled by m adjusting screw on the gun. Fluid material viscosity is in the same viscosity nnge as SAE 30 to SAE 40 oil at room temperature. Siphon CUD 1. ADVANTAGES ?he minimum apparatus of siphon feed equipment allows the installation of a spray system at low initial invert. ment. It provides the convenience of wing small q u o tities of material which can be changed easily for color or type. The spray gun, and its container of material, can be carried to work that is situated at remote places. The Only limitation to this would be hose length and air pressure capacity. 2. LIMITATIONS In siphon feed. the siphon tube y u r t always have its intake end submerged in the liquid material. In practice, however, this is not a limitation since the dogleg shape of the tube, and its adjustable position in the cup. allows aiming the spray gun through 180° from vertically down. ward to vertically upward. The nozzle design and pressure range neefor useful siphon effect on siphon feed guns limits the shape and size of the spny pattem. It also limits the rate of spray application to a maximum of 16 nuid ouncmper minute, m e weight of the siphon cup and its contents can be tiring to an operator if he is obliged to spray for periods of long duration. Mix Air Atomizing Nozzle 3. MAINTENANCE & CLEANING The cup gasket should be replaced whenever It drys out, becomes cracked, or otherwise deteriorated. The cup should be washed thoroughly In a solvent that will cut Ihe paint. Solvents Ihnt might attack or react with the cup material. should not be used. After the cup is Ihoroughly cleaned, it s e m i as the container for a supply of clean solvent for Iinai cleaning flush-out ofthe S P ~ gun. Y 4. PRECAUTIONS ?he vent hole should be checked frequently to be certain it is open. The siphon cup should never be altered for the purpose of converting it to a pressum vessel. 5. ACCESSORIES The following accessories for siphon cups M available from Binh: llasticdisposible linen to facilitate clean-up and color change. Cupstniners. Cup agitator (roUry or trigger actuated reciprocating type). Seal-tight coven for short-term storage of paint in the cup. . . d Punucots' 72 Airbrush ?hc prenwe eont~inorh capable of handllq l y e num. ben of rpny guns; the only Umitation h that It be dzed and adequately quipped. C PRESSURE FEED In thh method, materid ls delivered, under pmture, to the spray gun either by a pres" (compresed lk)container, or by a materid handling pump. I h e preuurizcd container delivers material one-way (deadend) to the rpny gun. ?be pump IIW delivers materid "deid+nd", or. It may be uud to drculate material continuously I "the c o n k e r , out to one or more s p n y rLltionr, and back to the container. Origind material container or an inner-liner can be p i m d h i d e the prczrure nucl IO ntinimizetime lost in clean.up. I h e presswe vcrrel tenes u a sealed storage container for the material. 1. M E PRESSURE CONTAINER ?be prrsnvl container h a cup or tank containing the material that la supplied to the spny gun under lk pres. m e . I h e container and gun may be coupled together u one w m b l y . or. the gun may be hooked up to a con- k e r by hose. Tbe tank M designed to withstand pressures up to the of each vewl. Pressure tank conform to ASME (American Society of Mechmierl Engineers) swIduds M labeled for 110 psig maxi. mum air pmnrre. Ihey nnge in capacity from 2 gdlonr to 250 gallons. Non-ASME tank ue n t e d and b l e d for 80 pdg maximum. capacity stamped on the dde Fluid Resure cups are aizcd for 1qt..and 2 qt. capacities. ?bey are n t e d for DRSSURcapacities of lex than 50 F& and M so marked by the rkufrcturer. R e m &PI are non-ASME 'Ibe ASME tank ue e l t i n e d by the manufacturer and curg his permanent stamp. I h e pressure ntinp on contriners ue Invalidated when they M reworked by being belted, drilled into, or rclded onto. Mart city, ate, and I n d u e d safety codes require that pressure tank be ASME Ilkled. Such containen ue refsmd to u "code" tank. U ?be lk presswe capacity for which pressure vessels M nted must not be exceeded because Its Wiure under pressure could be harmful to personnel. All pressure vessels rhould be quipped with pressum limiting controls. 2. OPERATION AND CONTROL I h e delivery of compressed air supplled to the container ls controlled by a pressure re-tor. k u r e control, together wlth selection of nuid n o d e orina size, and muvn M adjustment of nuid now valve, provides control of n t e of now of material from the spray gun. Fluid pressure mgulaton are used in the nuid lines when more than one spray gun is fed from a single tank. 4. LIMITATIONS Container refilling mtermptr the work by mrkinp it necessary to depmrurize the system. 3. ADVANTAGES A simple and low cost controlled way to force feed material to a spny gun. llme lost in dean-up during color changes. However, thii can be minimized in set-ups consisting of only I few colors by having a separate tank for each color. Capable of delivering a wide nnge of materials. Simple maintenance - no momg parts. Weight of large tanks and contents require lifting equip. men) far handling and relocating. Utilizes alr pressure which is already available in a plant or at the contranor's job site. Ressure containers M be used only in a deadend (one. wry now) system, (pumps M required in a circulating system where materid is retumed to the container). Spny guns supplied by hose from a container my be operated in any position. Containers must be kept vertical to avoid sloshing, splashing. and frothing of the m a t e d in the container. 73 R e m m the remaining mated. Clean the container and pow in a small quantity of suitable solvcnt. Wipe off .spray gun, container. and hoses with solvent dampened mg. Remove air n o d e and clean as necessary. (Caution: Do not use wire brush nor metal probe in air holes). Replace lid and pre.suri7.e the container. Tum off atomizing air to spray gun. Squirt solvent through spray gun into a suitable waste container: “triggering” spray gun until solvent comes through clean. ‘Blow out” solvent f”spray gun, container, and hose. Ressure capability is limited to the rating of the vessel and to the air supply cap8city of the plant. 5. CONSIDERATIONS FOR SELECTING PRESSURE VESSELS The volume capacity of spray gun pressure vessels range from 1 qt. to 250 gallons. In general, pafnting contractors and industrid maintenance departments find the 1 qt. to 10 gallon sues useful. In-plant production painting, departments. in continuous flow manufacturing operations. select capacities up to 250 gallons. Thk type of container to be selected s h d d also take into m n t material viscosity. Heavy materials such as SAE 50. oil. or heavier, must have bottom cutlet containers. Another consideration is whether or not ingredients in the material tend to “settle out”. If so, a container with an agitator wiil be required. If the matelial is corrosive or reactive with certain metals. the tank may need to be stainless steel or specially lined. If a variety of materials pre being used, it may be desirable to use removable liners. he in-plant compressed air mrCe must have the piessure and volume capacity to meet both the pressure container and spray gun requirements. Coil the hose. In some instances it may be desirable to keep the system wet by filling it with a small quantity of petroleum hsed solvent such as kerosene. This prevents hardening of any residue material. ABOVE ALL KEEP THE EQUIPMENT CLEAN. I. MAINTENANCE Pressure container head gasket s h d d be reolaced when air leaking occurs around top of container kith clamps HAND TIGHTENED. CLAMPS SHOULD NEVER BE WRENCH TIGHTENED. When unable to control fluid pressure. check air I’eguIator to sn that it does not “climb” above ”set” pressure. The spray gun will “spit” when the fluid pick-up tube connection is lwse inside container, Remwe tube. Seal with D Uue& compound such as pipe dope or teflon tape. Replace tube and tighten. &place gaskets or sepk t o stop air leaking out of container dagitator M. Tighten cap and replace gasket to stop air leaking quiek-fill cap. d- 6. START-UP PROCEDURE Connect air hose from the air supply to the inlet side of the regulator on the container lid. Check d m i o n of air flow. “Back off’ regulator to prevent air flow into the container. Open relief valve. Connect air hose from air pressure regulator t o the S P r s Y gua. &ect fluid hose f”container to spray gun. Remwe lid from container and pour in a small quantity of compatible solvent (this material is to be used as a test fluid). If container is a pressure cup. at this point connect cup directly to the spray gun. Securely tighten lid. Tighten clamps uniformly, going around several t i e s . and turn on air supply to container. Listen for air Am from relief valve. Close relief wlve and set air pressure level at regulator. Check air and fluid lines to spray gun for I&. Remove solvent from pressure container (seeshutdown procedure) and hi1 with material. Do not fill the pressure tank to its brim. Leave several inches of air space to permit .proper operation. The materid will flush the solvent out of t h e Auid hose leading to the spray gun. I 7. SHUT-DOWN PROCEDURE Fluid Pickup- Close air supply valve to container. Release air pressure in container by opening relief valve. Leave relief valve open. Do not use safety ”pop“ valve on ASME tanks. I t is a violation of code to use safety relief devices for normal operating functions. Tube j I i i S. PRECAUTIONS Never exceed the pressure rating of the container as marked thereon. Never make any physical modifications to a pressure container. Never use corrosive materials in a container not designed to handle such materials. Never remove the safety relief valve. Attach a ground wire for added protection from static electricity. Open container to the atmosphere. Loosen air n o d e on spray gun. Hold a piece of wadded cloth over the air nozzle and trigger the spray gun. Atomizing air pressure will force the material back down the hose into the tank. 74 , Never we name to clean I pmrure contrincr. Use only paint stripper or solvent. Air control assemblies available with ule followins com. twions: No rqulatoa (air must be controlled from I remote Always tighten clamps on a pressure container by band, two at a time, diametric& opposed c h p s . W W ) . Never tilt a pressure container while it contains material. This fllls the air regulator pawages with m a t e d and causes unnecessary elean.up of the lid w m b l y . Never position a container lid so that oil drains out of its agihtor drive gem box. Never attempt to open I pressum container without flrst venting the pressure. Main Air Never use high pressure air or a hammer to loosen a container lid. Remove lid by prying with a bar gently and only at clamp points. Always refill the pressure tank through the quick-fill port whenever possible. This minimizes frequency of removing the lid and thereby extends the life of the lid gaskets and clamps. Air 1 Always clean spiiied paint off the tank rim before in. stalling lid. Keep rim clean. 10. ACCESSORIES Pre-formed plastic disposable liners for 2-gal.non-ASME and for 2-. 5-, B 10-gal. ASME pressure tanks. Remote Air Control -TOP Outlet Container With Hand Apit.10r One regulator to regulate air only into the container. Single Regulator Air Control TOPOutlet Contamer Multiple air or fluid outlets for muiti spny p n operations. - Two rcgulator-control: one t o regulate air into the container; the second,IO regulate air to the spray gun. \ - Double Replator Air Control Ilottom Outlet With Follovrcr Plate 7s - Agitator assemblies: Hand, air motor or electric motor driven. peller to the fluid outlet near the outside. These pumps m m a high volume (1,000,000 GPM) of marcrial at lmv pressure (2,000 psi) and can handle either abrasive o r corrosive materials. They are usually not aelfpriming and can only be used to move low viscosity fluids. M Centrifugal pumps Fluid stminers for filtering the material as it leaves the container. Caster bases for mobility of the pressure container. Nonsparking wheels available. Turbln8 Pumps Turbine pumps use a high-speed turbine to move low viscosity materials at moderately high pressures (up to 500 psi) and moderate flow rate (200 GPMLThey are designed to handle non-abrasive, low viscosity materials and are normally not self-priming. Inner liners for containers to minimize labor in color change and clean-up; may be plastic. galvanized. or stainless steel. Turbim Pump "Off-set" funnel fluid strainer for adding paint to the container through the quick-fill inlet. D. FLUID HANDLING PUMPS Fluid handling pumps are available in a wide variety of designs to meet the requirements of various applications. Each type of pump hu its own performance characteristics which make it suitable for specific uses. Pumps fall into two major classifications: hydrndynamic or hydrostatic. Hydrodynamic Pumps Hydrodynamic, o r non-positive displacement pumps, a r e primarily used t o transfer fluids when minimal resistance t o flow is present. They provide smooth continuous flow of material. but their output is greatly reduced as resistance increases. These pumps continue to run when flow is completely stopped. Two main types of hydrodynamic pumps are centrifugal and turbine. C.ntrifug8l Pumps Centrifugal pumps use a rotating impeller to push the material from the fluid inlet near the center of the im- HydmNtic Pumps Hydrostatic, or positive displacement. pumps deliver a given volume of material for every cycle or revolution. Their rate of delivery depends on cycle rate or speed and the amount of displacement per cycle or revolution. Hydrostatic pumps are available in a variety of designs, including gear, helical screw, flexible impeller, rotary vane, peristaltic, piston, and diaphragm. G88r PumpS Gear pumps use two meshed gears to draw material into the pump and discharge it. Gear pumps can dispense medium volumes (3.000 GPM) at pressures up to 2.000 psi. They can handle viscous and corrosive materials but should not be used with a b m i v e materials and should never be n m dry. They are self-priming and are usually bidlectional. n HIIiul8anr Helical acrew pumps uae I drive screw and meahing idler screw to create continuously moving poekeu dong the u i s of the pump. These poeketa draw materid into the inlet and puah it out the outlet. Helical a m pumps can develop fluid pressures to 550 pai and volumca to 270 CPM. They provide smooth, continuous flow and can be rued with corrosive materials up to 1.000,OOO centipoise viscoaity. They have excellent suction lift and are selfpriming but should not be run dry. Helical Screw Pump flaxibla Impdler Pumps Flexible impeller pumps make use of the changing volume of chambers to drnw materid into the pump and discharge it. They can deliver volumes to 300 GPM at pressures to 100 psi. They can handle viscosities up to 1o ,OO centipoise as well as corrosive materials. They are self-priming but should not be run dry. krh0)tlC Pump. Periatlltie pumps we a aerier of mllen or cams to push t h e fluid through a piece of tubing. The fluid being pumped comea in contact with only the inside of the tubing, which eliminates contamination of the fluid and compatibility problems. These pumps can pump abrasive or corrosive materials at a rate of up to 300 CPM at pressures of 100 psi. They are self-priming, can be run dry, and can handle marerial viscosities up IO l0,oOO centipoise. Plston Pumps Piston pumps use a reciprocating piston and a series of check valves t o draw fluid material through the inlet into a chamber and force it out through the fluid outlet. These pumps can deliver volumes of material up to 3.000 CPM and extremely high pressures in excess of 75,000 psi. They are self-priming and can handle high viscosity materials up to 1.000.000 centipoise. Piston pumps can be used with mildly abrasive or corrosive materials. Flexible Impeller Pump Rotary Vane Pumps Rotary vane pumps use vanes which slide in and out of a mtor to form chambers within the pump. Because the mtor is mounted eccentrically within the cylinder, the chambers become larger and smaller as the rotor turns, which draws material into the pump and discharges it. Rotary vane pumps deliver medium volumes (100 GPM) of material at pressures to 1000 psi. They can handle mildly abrasive or corrosive materials and viscosities up to 10,OOO centipoise. The sliding vanes compensate for wear. These pumps are self-priming. Diaphragm Pumps Diaphragm pumps are one of the oldest pumps used by man. We have progressed from animal skin dmphragms through mechanically driven single diaphragms to air driven double diaphragm pumps. In the past 35 years. design innovations have made the air driven double diaphragm pump one of the most reliable. versatile broad application pump available. Ir Diaphragm Pump H-High M-Medium L-Low Y-Yes 78 N-NO 1. THE RECIPROCAnNGPISTON PUMP The reciprocating piston pump is the type most commarly uaed in a moterial spraying aystem. It consists of tw d o n s : the power section and the fluid section. The power section either can be an air driven or hydraulic motor driven piston thnt is d i t m e c t e d to the W i d handling "Euid" pism (* be'w)* Or & "lMd"piston can be driven by an electric motor thrpKh a piston rod and crankshaft linknge system.! B i n h Comet pump q d Binka Super Bee pump outfit are examples of air dnven and electric motor driven reciprocating piston system respectively. . NOMENCIA'LIRE me mgement of eomponenrs in a recipmating piston pump and thew sequence of operation are shown %hemtidy hiow. Pilot VaIw Piston7 Pilot Valn Pinon- Air In d Air Exhaust Pinon Rod T h r M Packing Prruun Onchug* ChamMr Flu16 Piston Flwd Cylinder Pntm Bad" V.IW Inpke Chambar FWI V l l w Mitend In A,. Input Vmmd Pilot A W - -- - Exhwrt Air --- Air Motor Driven Reciproating Piston Fluid Pump 79 pomacuon RounDischam Chambn The air powered piston-cylinder "motor" ansembly h a t e d In the fluid cylinder, this chamber receives nuid from the intake chamber on the downstroke of the fluid pirton. including valving, rod, seals, etc. The electric motor, gear reducer, crankshaft, and piaton rod assembly, Fluid Section b. WMPOPERAnON RIM -on Compressed air enters chamber above piston. Piston moves downward. I b e pistonsylinder awmbly driven by the power section that pressuredelivers liquid material to the wv gun. At end of piston Stroke. lctwtor triprod reverses air idve which: Stops flow of compreued lir to upper chamber. Aliowa upper chamber air to exhaust to atmosphere. Wows compressedair to enter chamber below piston. Air Piston The reciprocating member in the power section. ?he piston is poweted by compressed air. Air Valve NOTE: Switch-over of air flow fromtop of pirton to Directs the flow of compressed air altemately and. in correct timing, to each side of the air piston. bottom of pistonis ahNpt and occwr instantaneously at g& of piston stroke. It is not related to movement of the piston but, nther. to -P of the piston. This mode ofvalve action minimizes the time during which pressurized lir is flowing simultaneously to top and to bottom ofpiston. Acruator Trip-Rod Controls the sequencing of the air valve. It is directly connected to, and is actuated by, the air piston. Fluid Piston Piston moves upward. Tne reciprocating member in the fluid section. ?his piston is directly connected to. and driven by, the air piston. At end of upstroke, actuator trip-rod revems air nlve which stops flow of compressed air to lower chamber. AUows lower chamber air to exhaust to atmosphere. Mows compressed air b enter chamber above piston. Piston Rod l%e member directly connecting the air piston to the Piston moves downward. nuid piston. I b e repeating cyde of the power section describedabove is olled the reciprocating power rtion. Ibis r t i o n is h.nrmitted dimtly. by piston md connection, to the piston in the fluid section ofthe pump. Air Motor W i n g and Throat Rdting Rubber, leather, or synthetic mterid serving to pmvent leaking of air m d nuid out of the power and fluid sections at the piston dDd: Air Cylinder and Fluid Cylinder I b e '&rarting power stroke is alled "double-acting" k a u w the air piston is "driven" by compressed air on the downstroke and llso on the upstroke. ' h e tube-like chambers containing the air piston and fluid piston. They are appropriately valved IO as to receive and discharge air and fluid respectively. of mciprocatlon is controlled by n t e of now ofpmsurizld air into the power section. An air regulator in thecompressed air h e isused for thii control function. For a patticulu nte of flow of pressurized air into the power section, the speed of miproation rill increase with a d m l v in resistance of now of the m a t e d out of the spny gun, and vice vem. fluid Section I b e speed Top Cap and Bottom Cap T n e end members of each cylinder that close off the tube to form chambers. Cup S a l and Piston Body Rdting Rubber, leather. or synthetic material nxed to the peripheries of the air piston and the fluid piston, respectively, to prevent air and nuid from leaking past Upstroke the pistons. Intake Chamber At the piston moves upwud. it dnws m a t e d through the foot valve into the intake chamber. As the piston Foot Valve moves downward. prrsure OD the material forces the foot valve to d w and the piston body valve to open. Continurd d o m w u d movement of the piston forces material through the p ' d body d s e into the p m r e d s ic h w chamber. Revents e m p e of fluid material out of the intake chamber on the downstroke ofthe fluid piston. Piston Body Valva At the piston again moves upwud, pressun on the material in the discharge chamber form the piston body valve to dose. Thi action rlro pushes the material out of the dischage chamber into the supply line Controls nuid flow from intake chamber to pressure discharge chamber in the fluid cylinder. to the rpny gun and, simultaneously. again dnws matexidinto the intake chamber. h a t e d in the nuid cylinder. This chamber receives fluid from the material supply on the upstroke of the nuid piston. 80 ! i Ar the piston again moves downward. material is f o m d into the direhuge chunber from the intake chamber. u described above. A highly desireable feature of pump opention h to Iuve constant, noniurging, nte of flow of material output. The pistoniess pump shown in section "D", for example. would deliver material at a flow nte that is u constant u the nte of flow of compressed air into the pump. During opention of the recipmating power pump (des. cribed above), material would flow out of the spny gun only on the upstroke of the fluid piston. On the down. stroke, material would NOT flow out of the gun because the motion of the fluid piston. and its compression effort, are in a direction opposite to that of the material flow. However, through ingenious design, this opposite compression effort has been made to wist flow of material out of the gun rather than to retud it. This mistance serves to maximi= uniformity of flow and to minimize surging. This was accomplished by sizing the diameter of the pis. ton rod to a dimension that would make the volumetric capacity, swept by the fluid piston, twice as iuge in the intake chamber u in the pressure discharge chamber. Thus. one hair of t h e material entering the pressure dm. charge chamber from the intake chmber, on the d o m stroke, remains in the pressure dischuge chamber. The other half, also entering the pressure discharge chamber, must, necessarily. move out into the spny gun SUP ply line. ?hen.on the upstroke. the remaining one half of the m a t e d moves into the supply line. Therefore, the m o u n t of material that is moving out into the supply line is the sune on the upstroke u on the downstroke. c. PUMPRATIO The term "pump ntio" derribes pump perfoomunce. It h useful in comparing one pump to another and in appraising the condition of a pump during its working lifetime. "Pump ratio" is a general term. It un refer to theoretical pump ntio, stalled ntio. or openting pump ~ t i o . These latter. more speciflc terms. should be rued when discussing pump ntios in order 0 avoid misunderstanding. THEORETiCALPUMP RATIO is the ntio of"efreective" area of'the air piston to that of the fluid piston (not counting piston rod). "Effective"uea is the contact m a of compreswd air on the air piston (and of fluid mated on the fluid piston). STALLED PUMP RATIO relates pump nuid pressure to & p m m when the pump h stalled out. S W e d pump ntio is less than theorctial pump ratio b c u w of friction within the pump. OPERATING PUMP RATIO relates fluid pmsure to air pressure during the time that a pump is stroking. When a pump is stroking. under constant air pressure, the stroke nte will increase if Spray gun nowle size is increased. or if material viscosity is demased, or both. Under these "if" conditions. at constant air pressure. mterial nte of flow will increme because resistance to flow h u decxeued. d. ADVANTAGESOF RECIPROCATING PISTON PUMPS They cm handle a wide variety of fluid or semi-fluid materials. They have a wide range of operating pressures. They cm draw material directly from the original container. Material can be circulated to keep pigment in suspension. They M be controlled to deliver material in large or r d i measured quantities. or at random demand. They permit fast color change and clean-up in small ryrtem* lhey cm be used d e i y in hiurdous locations because they ue air operated. a. CONSIOERATIONSWHENSELECTING AIR-OPER- ATE0 RECIPROCATING PISTON PUMPS The customer flnt must know what his maximum Rquirements ye concerning nuid dkharge nter (gallons per minute) and p-re (pounds per square inch). These h c t o n ue reiated to fluid nozzle orifice size. After determining the required fluid disdruge rate and pressure, the appropriate pump fluid section and corresponding power section can be selected from manuhchued charts and tables. These tables -late fluid dis. durge nte (gallons per minute), pump speed (cycles per minute).and comprerced air requirements (cubic feet per minute) at various air pressure levels (pounds per squue inchi. The following general guide rill sene in relecting suitable theoretical pump ntios to handle adequately the various kinds ofmaterills encountered in spny painting: Selections should always be on the high side. Ovemze pumps will have a longer life and, genenlly. wiii suffer less wear m d will require less maintenanee. Note that material ingredients, viscosity, and distance to be pumped. are facton in selecting pump size. Ratio THEORETICAL PUMP RATIO Uquid tnnrfer 1:1 lhin & medium viscosity 21 (dmllU to SAE 10 oil) Horizontal, short distances Horizontal. long distances 2 1 plus Vertial rise (0.5 p81 per 1'-0" rirc for rater) Medium & heavy sircoslty 4:l to 6:l (slmllU to SAE 10 oil) Materials that contain short fibers or sand Nlen Heavy Nlers E l to 101 Long horizontal distances Vertlal rises Hot airlev spraying ' 17:l Industrial coating materials 30:l at room temperature,such as for general maintenance. Extrusion materia 6 1 to40:l Difficult to atomize materials Shut-Down R o a d u r a With pump running at slow speed remove it from ma. terial container. and let it pump air just long enough to empQ fluid section. Race pump into container of clean solvent and circulate solvent through the pump back to the container. Repeat this procedure with dean solvent until pump NUSclean. Several "short" nushes ue more effective Uun one long flush. Remove and clean any fllteers that may be in the system. Rslacemble Nters. KWD svstem "wet". Fill pump with an oil base solwnt or & &en plnstidsu, such Di Octyl Terephthalate (D.O.T.P.)or Tricresyi Phosphate (T.C.P.). This will keep parts lubricated and AI prevent any residual m a t e d from drying and hardening inside the pump and causing subsequent damage. Wipe down 111 exparcd p u t r of pump with solvent dunpened rag. Lubricate air motor with a light machine oil or T.C.P. A few d r o p in the air inlet is sufficient. Caution: Do not use oils that contain silicone. f. OPERATION & MAINTENANCE Grease the fluid section If it is equipped with a grease sonup ntting. Set pump in a solvent compatible with the material to be used. Store pump with the piston in the muimum down position; keep upright in storage. Run pump In solvent 10 u to nwh it thoroughly. g. ACCUMULATORS IANTIPULSATION CHAMBERS1 Take pump to Its sW1 pressure. Check for leaks in the system either externally or i n t e d y . The p r e s s m applied to material during repeating cycles of a recipmxting power pump, varies as shmn. If the pump does not stall and there uc no extemd leaks, make sure the back pressure valve (if any) is dosed. Continued failure to sWI Indicates that piston packings or check valves are leaking. Shut down pump, relieve pressure and =pair u needed. (see p u t sheet for instruction dealing with your model pump) Tbe pressure on the fluid reaches I& muimum level very quickly at the s t u t of each stroke and material is forced thmugh the system. The pmsure holds constant throughout the stroke. At the end of the stroke there is a m e w n r y t drop In fluid prruurr u the piston changer h t i o n in order to commenrr the rem stroke. During tbi~ very brief period, a drop in premue is experienced at the spray pn. lhir lnercue and d e " in pressure is d e dm e . When pump stalls correctiy, mmove fromsolvent and place pump in the material container. M o w pump to dircharge the solvent used In the start. up procedure and begin spray opention. Surging Is undesirerble because It show up visibly on the f i e d paint surface u an uneven mating. To some extent, surging M be conuolled by fluid prwure regu. W n ,p a r t i d u l y if the p r r u m on the high side of the mfulitor is considerably higher than that on the low side. However, If the high side pressure is only slightly higher than the pmture muired at the spray gun, surgine at thegun will bemorepronounced. A common way to minimize surging is to use an accumutntor. Essentially, this device, is a rese w o i r of stored-up material. under pressure. The pressure may be supplied by weights, compression springs. or compressed air. During Spny Operation The pump delivers material to the spray gun on de. mand; the more material required the Cuter the pump will opelate. Operate pump a t the lowest possible pressure that will deliver the quantity of material needed or the atomi. a t i o n required. Keep pump filled with material at all times. Do not let pump draw air or lose Its prime. Ovamight Holding Practice An amptable ovemight holding practice is to allow the pump to circulate material slowly through the pipe or hose line from container to spray gun and Tbe pmsurr In the accumulator is developed during the mrin portion of the pump stroke. %en, during the inter. vd that the pump is reversing Its stroke. and normal line back again. This holding practice must not be used with materials that "set-up" through a t d y t i c , or chemical curing, or which tum abrasive or corrosive. pressure momentarily drops. the stored up material will be fed into the line to cover the brief intend of pump depresuriution. The ovemight holding period should not exceed 16 houK. 82 UpnIOb Sun Downstroke Uptroke End Oownnmk. Umtroke ASCumuImOr Wn they will wort safely under the pressures. tempenhun, degm of rough handling, and other conditions they are subjected to. 3. PRECAUTIONS Never e x m d the manufactured spcei5ed muimum d e livery ntig of the pump. 4. ACCESSORIES Never use excess air pressure to drive the pump. Excessive speed will cause undo we= on the pump and will wute material. Strainers and Nte~ at inlet to. and discharge from,the pump. Alr regulators to control air pressure to the pump air motor and to the air atomizing spny gun. Always check material to mlke certain it will not d m q e the fluid section ofthe pump. For exampie: Agitators for mklng the material to prevent settling. to prevent buildup of stall Uquld p ~ u r regulators e pressures and thereby avoid surge of material when the spny gun is higgered Anti-freeze i n k t o r s or oilen installed in the alr Unes to lubricate the &,motor and prevent freeze-up. Mixing tanks and standpipes for mounting circulating Water bued materials require corrosion resistant puts in the 5uid section. Materials that contain strong solventr may require special plckinting. Materials which contain Nlen or abruives should be handled by a pump with a large-volume delivery capability. Such a pump will run slowly and thus will have minimum wear in the fluid seetion. Hardened components may be used In the pump to further minimize weu. pumps for miring, distributing. and storing large volumes of matefi. Accumulaton to reduce 5uid pulsation and assure uni- fonn spray pattern when using air operated reciprocating Always supply the pump with an adequate volume of air to do the job. 'Ihe air supply hose should be of sufficient inside diameter to handle the zequired air volume at the available supply pressure. pump Manual presture relief valves to bleed the line of high P .Intemai drum strainers for suction feed from drum. Keep pump lubricated u recommended by the manuhcturer. One method of lubrication Is, periodidy. to pour a small quantity oflight oil or T.C.P. down the incoming air line to the pump. Be certain that the oil does not contain silicone and that the b a u and intemrlah motor parts will not be damaged by the lubricant. E. TYPICAL MATERIAL PUMP INSTALLATIONS 1. "DEAD-END" NONCIR~ULATING 'Ihe dead-end system delivers matefi on a one-way trip to the l p n y station, either neuby or remotely located. It is the m a t common type of pump Instahtion. It gives a qlulity linwl rltb materials that do not settle out and that do not requite heat. The s p n y gun material hose is hooked up directly to the pump (see below). With e o n v e n t i d air atomizing equip Pump quipped with dpbon tubes must be kept "wet" and must have dl their connections tight. W p u m p ahould be eleehidly grounded to prevent the .ceumulation of static electricity which could spark m d cause fits. Use only " e t SYSTEM ment. a Sseond how supplies the atomizing air to the spny gun. With airlesa spny, d y one high pressure hosc is conmtcd to th rpny gun. hoses and 5ttings on pumps. W e cer. Alomiz,na Air HOU Non-Circulating Systems 84 . I h e "um prrirurr ap.dty of the filter housing l b d d be greater thm tbe mrbg pressure of the ryrtcm. I h e degree of comdveness and abnrivrncu of the fluid to be handled will determine the type of mated used in the filter houring and element. 2 CIRCULATING SYSTEMS The circulating system moves material continuously through a closed loop of hose or pipe, through one or more spray stations. and back to the material supply container. The spray station may be either nearby or remotely located. The arculadng system offen a number of advantages: 2 MAINTENANCE OF FLUID FILTERS Experience will establlsb a best rminterunce schedule. Once established. It should bf followed The clored loop drcuhw system M be provided with heaters and material m i r i n g agitators that will insure holding comct applicadng- tempenhues m d prevent settling out of materid ingredients. lbis erpabillty d o a s spny application of I widevariety of mated.lr. including wphlstlcated ones formulated with exotic ingredients. to provide particular coating fllm properties. Various subputc may be painted at different spny sadons and yet have perfect color match when w m b l e d because they ue supplied and sprayed with the identical paint. Nten must be cleaned regularly. Nten should be inspected when the following conditions become noticeable: Matedal flow is sluggish or excessive pressure is needed to deliver the required material. This ndrmally indicates the Nter requ!aes cleaning. Some fllters automrtiuUy indicate need for cleaning. mal Iinish is rough, p i n y , or dirty. This Indicates the filter element is either b m h n or being bypassed. A comet p u t aheet and an adequate supply of span putc should be stocked. F. FLUID FILTERS A fluid fitter is used to remove thou particles from the material which would contaminate the Gnat finish or plug the fluid nozzle orifice of the spray gun. 0. FLUID PRESSURE REGULATOR A fluid pressure m a t o r is a device for controlling the prnsure of Guid flow to the spray guns. It is mounted on the dischuge side of the fluld pump as dosc to the rpny guns as is practicable, 1. CONSIDERATIONS IN SELECTING A "FILTER" a. FILTER TERMINOLOGY Mah 'Ihe number of openings In a linear inch. Sunen o w i n g ?he site of the r m n holcopening measured In thousandths of an inch. Microns l b e unit of measurement for putlde size. It is equal to one thousandth of a millimeter (.001 mm). 25.4 microns equal one thousandth of an Inch (.001 In.). Particles Iaqer than the micron n d n g of the fluid filter cannot p a s through the fiiter screen. Filtering am h a of m Ruld p m rrpulatonue sized recording to the degree of eontml m d to the mgr in prnrun that is desired For example: A rpnying.opendon bas a pump capacity . of 160 pdg. lhir "vm pressure can be regulated so that the spny p n rrclivn fluid materid at from 3 to 55 psi& or, with a d e r dze regulator, It Mreceive fluid material h m 1 to 12 pslg. For m y wtthg of the larger apadty regulator, adjustment in premve un be made lo incremerib of approximately 1 pig; of the smaller, approximately 1/4 Mg. 1. OPERATION OF A FLUID PRESSURE REGULATOR Ibc setting of regulated prrsrure level Is accomplished by adjustment of spring c o m p d o n against one side of a diaphragm. Fluid pressure in the Une, on the outlet d& of the regulator, prrrses on the other side of the dhphngm balancing the compression spring load. 'Ihe movement of the diaphragm, caused by a change either in spting load or in outletaide pressure, controls a needle nlve oriflm which, in turn, controls material flow tbrougb the regulator. MW n expoxd to the material flow. b. SCREEN SIZE REQUIRED FOR A PARTICULAR MATERIAL Screen Opening Mesh Microns Metallic paints and primers Solid colors Sealers and solvents Low pigmented fluids BufGng compound Mrttics and sound deadenen Mrttia containing long fibers .009 .005 .003 .002 .020 .030 .050 .030 .040 .050 60 100 228 149 76 43 500 An inneve in outlet&& nuid pressure (as when turning on one of v v e d spny guns) d l unbalance the diap m load. This will compres the spring and cause the diaphragm lo move and to decrease the am of the needle nlve oriflce. Fluid flow through the regulator into the r p n y gun supply line will then be reduced as will be the 200 325 35 Perfonted mew nuid p " e . screen "Stab" s e m n openinjp. Made by stabbing holes into sheet meW 10 L1 b produce bum. 85 Id Fluid Re 1n-Llna Filter 1 Circulating Systems 86 . 8.d: Prarrura Regulator “dli 2 CONSIDERATIONS FOR SELECTING FLUID REGULATORS TION. and PRECAUTIONS for a back pressure regulator ue dmuU to thav for a fluid p m r w regulator. What is nuximum required volume flow nte of matedd? What is maximum required working pre*iure nnge and pressure controi sensitivity of the system? Select 0.12 Ibs. for the delicate control required with electrostatic spnying or pressure sensitive fluids. Select 0.100 Ibs. for normal spraying pressure control. Special high pressure regulators ue requlred for airless spnying. k the material to be hadied by the regulator c o d v e or abrasive? Q h tis the pipe size of the circulating system? What will be the orientation of the regulator during open ation? Vertical, horizontal, etc.? 3. PRECAUTIONS Bypass valve must be closed when regulating material PRYUre. Never “blow back” the regulator unless the bypass valve is open. Material supply filters should be installed on the inlet side of the fluid regulator to prevent material build-up on the regulator valve seat and stem. Shutoff valva should be installed on both the Lnkt side and on the outlet side of the regulator to permit servidng the regulator wiqout dosing down the entire system. Never exceed the recommended working pressure of tbe regulator. The regulator should be l w t e d as dose to the spny gun as pcssible. Read manufacturer’s instructions pertaining to opention and maintenance and follow them faithfully. H. BACK PRESSURE REGULATORS The effort required topush fluid material through 8 spny gun nozzle is supplied by the reciprocating power pump. In a “dead-end” material supply system, the pipe line be. tween pump and gun has oniy one outlet, the gun n o d e . All of the pressure in the system,therefore, is acting at thegun nozzle. None is lost (discounting friction loses). In a “circulating” system.on the other hand, thew is 1 “retum” pipe line to the material container. The free flow of material out of the open dirherge-end of the retum line prevents the buildqup of pressure in the line that is necessary for pushing material through the spny gun nozzle. In order to retdrd this free flow of material, a “back. pressure” regulator is inserted into the retum line down. stream of the several s p n y guns in the system. This allorr pressure to be built up and maintained in that portion of the pipe line supplying the spray guns. and, at the same time, allows material to be retumed to the supply container in recirculation. The back pressure regulator (see page 18) is adjustable and Drovides variable control over a Dressure ranee - ip .propnace to the system of pump, spray guns. and nuwnd.The OPERATIOX. CONSIDERATION FOR SELEC. II GLOSSARY Agitator: A device for stining the material in the conWner to keep the paint from settling out. It may bo powered by hand, alr. or eleckic motor. BJC Rsuure Valvr w Regulator: A device used to malntain pressure In a pump circulating system. It Is located downstream of the spray guns. Bonom Outla Renun Tank: A pressure tank which stands on legs and has a bottom outlet. Used for materids that are heavy in viiscosity. O l o r Bme: A metal base wlth casters used to -port pressure tanks. Circulating Connection t“Y” Conneexion): Fits to the spray gun and allows material to circulate past the spray gun for retum to the material container. Circulating Wmm: A system for delivering material to the aevenl spray stations and allom retum of unused and excess material to the material container. Disposable plastic Liner: A plastic bag for lining the inside of a cup or pressure tank when containins material. It may be dispacd of when no longer needed. ‘This item saves dean-up time. D.O.T.P. DI Octyl Terephthalate: An inert plasticizer used to keep pumps wet. especially when they are handling the m m p e n t mate& of a multicomponent (PILIrsl) &lish or alting pmdua. Double Air Outlet: A pipe fltting w d on the outlet side of a pressure tank air regulator to supply air to two spray pm simultaneously. Double Air Regulator for Pres” Tmk Control: Two m g ~ h t omounted ~ in tdndem. One regulator controls .it pmrure to p r r u u ~tank and llro feeds main-line, unregulated, u r to a second regulator. The second regulator controls air pmrure to spny gun. This type of control is often wed by painting contnctors. Double Fluid Outlet: A pipe fltting used on a preisure tank fluid outlet to supply fluid to two spny guns rimultdneously. Edge TYP Filter: An in-line fllter compaed of a series of identical plates stacked together. Each piate has three leaves similar to a Meaf clover. The plates are so stacked as to allow fluid nuterial to enter through the center of the stack and to leave through the periphery. The maxi. mum partide size the Nter will pau b determined by the thickness of the plates. Fluid Regulator: A device installed in a pipe line for variable control of fluid pressure. Fluid Strainer: A Nter device installed in a pipe line to remove oversize putides. Fluid Sminer Funnel for Pnnure Tanks: A funnel with a replaceable strainer m e n and offset neck to permit filling pressure tank without having to remove the tank herd assembly. pump which dirplam a volume of fluid qrul to the volume of the piunger. Rntun Cup of Prerrun Tank: A rsaled contliner in which air pressure is w d to force materid to the spray Follown Plan: A met.l plate whieh rides on the surface of material in a prtbnue c o n h e r to prevent the incoming pressurized air from frothing, cavitating. or otherwise agitating the nuteriai. w. Foot Valw. QNck Valve. M Ball old Valw: A nlve located at the base of a reciprocating power pump which allows fluid to flow to one direction only. B I G : Pounds per s q m inch gauge. The prerture in a system as indicated by 1 dial gauge. Such a gauge indi~ t e“zero” i when the WStem is open to the atmosphere. Ratio of I Pump: The eNective area of the air motor piston over the effective area Of the fluid piston ( s n section I-Plc).l l w pump ntio number also defines tbe ~ sailing pressure of the pump. For exampie: a K I :ratio pump operating at 100 psie pressure will stdl at 1000 psig fluid pressure. Siphon Cup: I b e container for holding material when siphon spraying (usually 1/4 OL to 1 qt. In capacity). h n d Pip.: A small dimitter tank mounted with a fluid pump. ?he tank has 0 bottom inlet to allow fluid to enter and be pumped into the circulating system. Sbdi-Grip Cup (Remote CUP): A pmznve container of one or two quart capacity connected to the spray gun by horer. T.C.P. Tricnryl Phospham: An inert synthetic lubricant used to keep pumps wet during shut-dom periods. G u r Pump’ A pump in which material is forced into the Q h pressure side of a system by the r t i o n of rotating, meshing, gem. Gravity Buckn: A container with a fluid outlet on the bottom in which material is red to the spray gun by plvity. Head Gasket: A leather or synthetic lubber gasket used to seal the cover of a p m u n tank Inner Container (Liner): A container whlch is fltted into a pressure tank to expdite the chanfing of coioa m d dean-up. Material: The liquid pmduct being sprayed onto a surface by the spray gun in a coating or painting operation. Mixing TMk: A container ured for mizing luge qumtities of materid. UwYy it has a bottom outlet for dnwing off s d l quantities of materid u required. Pinon Body Valw: A check valve loated in the fluid piston of a recipmating pump. It dlows fluid in the pump fluid cylinder to flow in one direction only, I ” the intake chmber to the pressure dkehuge chamber. TaII-Talr Filter: A stnine1 with m indicator whlhich dt. plays i k “dirt-load” condition. Turbine Elrctric Pump: A Ugh volume rotmy pump used in drculrting Systems. The hubine blades u mrny rrmll individually endored propellen mounted on one stuft. me Piston Pump: A pump udng a cylinder and piston to force materid into the high pmsure ride of a system. Plunpr Pump OT Displ8ammt Pump: A mdprocatiag 89 Plural Component Spray Systems I. GENERAL DESCRIPTION The spraying of plural component materials can be compared, in many ways, with the apraying of a single component fluid such as paint. Plural componants can be sprayed by either compressed air or hydraulic (airless or air-assisted airless) atomization. The main difference is in the purpose for spraying. Usually a single component material is sprayed for the purpose of decorating and/or protecting the product. This same reason is also the purpose for spraying some plural component materials. Other plural component materials. however, are sprayed so as to build and become the very "nruclure" of the product. An example of this is fiberglass reinforced polyester. Here, the product begins with the spraying of the external "final" finish into the mold. This is followed by the "spray-up" of subsequent layers, thus developing the substrate structure of the product. Each component of a plural component system remains liquid until, i n proper proportion. t w o or more are combined during the spray process. Thus mixed and catalyzed. e chemical reaction lakes place causing the liquid to release heat and solidify, in a prowss called "thermosetting." The application equipment basically m u n meter two or more components accurately end deliver them separately to a mixing area or chamber. imparl enough energ,y to "blend" or mix thoroughly, and atomize it or causa it to flow as directed. It i s either sprayed directly, when atomized, into a mold to form a product, or on another substrate to become an integral part of it. "Flowed ma16 rials are not etomized. but when mixed are dispensed into cavities, containers or molds. They are usad to fill voids, "pot" components in assemblies, veal joints or duplicate the contours in molds or dies. 2. The viscosity of each component at appropriate temper. atura. 3. The materid component ntio. (By volume and/or weight) 4. The allowable tolerance in ratio and mixing. 5. The allowable temperature range of the material (when It should or should not be used), 6. The storaga or "shelf4~fe"of the material. 7. The storage requirements. 8. The flushing solvent required. 9. Can the component's viscosity be lowered with heat? 10. Handling considerations with regard to toxicity. A'llst of some types of p l d component materials (usually referred to as "systems") that u e spnyed or poured indude polyesten, polyurethanes. adhesives. coatings. and epoxies. These materials may be mixed in varying ratios 8nd viscosities. When considering the equipment requifed. one must look at each "family" or dry of material; what they u e chemically, and how they ue to be handled. 11. POLYESTER RESINS or F.R.P. (Fiber Reinforced Plastic) Probably the most common Wpe plural component is polym e r resin. (Ohm. this material is incorrectly referred to as "fibwglass"1. The polyester rqin bonds t h e lightweight. mong. flexible glass fibers into I stiff matrix to gain the physical properlies of both " r i a l s . Polyester resin is a "1OO.A s o l i d (no evaporative solvents) liquid chemical that cures by fusing into a thermosetting mass through the introduction of a catalyst (usual. ly M.E.K. peroxide or Benzoyl Peroxide). In other words, when the polyester is completely cured (hardl. there will be no appreciable lots of weight from its liquid state. The equipment required to dispense the plural components is basically modified or similar l o standard spray equipment. A spray gun with two or more heeds or fluid inlets and supplied with material from two or more fluid sections jointly driven by one power source (electric air or hydraulic motor) standard type hoses and controls comprise the basic system. TO consider equipment. one must fin1be familiar with the materials being used. The bat source of this information is the material supplier who, in many cases. is the formulator. The supplier should provide you with the following information: 1. The most suitable type of material and 18 application or end use. Polyester resins are generally classified as either "gelcoats" (which are pigmented polyesters) or reinforcing resins (structural resins or "lay-up" resins). Gel-coats usually are used as the firn (or color) coat in a product (comparable to the painted finish on a car or refrigeratorl. There are also polyester gelcoals which are used in the same manner as paint to offer protection against corrosion, and exhibit beauty or color. The "lay-up" resins are used with glass fibers or other fibers (such as cloth or mat) to produce slructures called laminates. They range in color from amber l o clear and are rarely pigmented. They are sprayed over the gelcoet and (the resinsl fuse themselves tothe fibers forming a matrix. The compo. nents then become a monolithic ("seamless") structure. 90 Common glass, I is W m l l y known. is a vrry britt10sub stance which will b r u k or hatter when deflrcted or imputed. This is beauso the large rurfico am with itJnunv ' t l w reduces its tensile strength. In fibrwr form, the d b c r e w size and surface area sharply reduce Ram. and the flexible plats fiber approaches its theoretical phmical strength. Tensile strength of the fiber is the prime factor of rnin~glasconstruction. In a composite of glass fibers and polyester resins, each is important, in its awn way. The polyester resin in its liquid state is plastic and adhesive. This material holds the glass fibers without damaging or reacting with them, yet bonds the fibers so they cannot migrate or pull out This type of composite also is able to distribute the mess evenly, as well as contain any individual fibers that might break. The combination of polyester resins and glass fibers are good structural materiels end offar the fabricator a number of advantages. Practically any shape article that can be de-molded is possible; since the polyester is liquid, it will flow and readily surround or capture any fibers of fillers. The desirable property of remaining in a liquid state et room temperatures and solidifying only when a Catalyst is added simplifies the type of equipment required to work with it. The temperature and mass of polyesters-have a tremendous bearing on the cure cycle of the resin. Usually. the cure cycle is in the area of 15 to 45 minutes, depending upon production rates and product design, and is controlled by the amount of catelyst introduced into the system. Catalyst is utilized to overcome an inhibitor which prevents premature polymerization of the resin. The amount of catalyst used usually varies from 1/4 to 4%. based on weight or volume. (continued below) cold rubrtnto. will ddav the cur0 time cycle 4 to 10 timn tho stated timo. Ifyou do not uhiwo a proper cure n the time yw g p l y the rarininp coltinpr. the glass fiben will pmRrJte the prwious Coating and possibly cause s u r f ~ e flaws. ShrinkrOcafdOr wrinkles m a y also be evident. Thee are caused by nyrme etching of the uncured r a i n on the glass fiber. High humidity will also inhibit good curinp, LT water and polyester are incompatible. 111. TYPES OF EOUIPMENT The equipment required to apply Polyester resins can be IS simple as a paint brush or as complex as an automatic unit programmed to automafieally select. meter and mix the right amounts of m8terial as required. However. the most common tvws of equipment used are outlined in the illus. trations that follow. 1. Premixed catalyst and resin (gelsoat or lay-up resin) applied by brush. Ideal for samples or hobby: no large equipment investment. 2. Premixed catalyst and resin sprayed with any conventional spray equipment. 3. Catalyst type mixing equipment: a. Side catelyst injector system. Mixes the components externally in front of the spray gun. The catalyst may be extended. or diluted, with an evaporative chemical such as ethyl acetate. Resin and catalyst are supplied to the spray gun with standard type fluid handling systems. such as pressure tanks or pumps. The equipment used on the catalyst side must bo constructed of corrmion resistant materials. See block diagram below: AtomWng Alr Uno R =Resin (polyester) P = Promotoar (coban Naplhanale) C -Catalyst fMEK Peroxide or Dlchlom k o y l Pemxde) Depending on formulation andlor application, the rains may hwe another chemical called a "promoter" or acceler. ator added. This chemical's lusually cobalt napthenate) purpose is to rapidly decompose the MEK Peroxide catalyst to effect polymerization of the rain. It is important to remember that when the supplier stat= that the material will cure in 20 to 25 minutes 8 72 degrees F. at 8 thickness of 15 mils. changing either the thickness or the temperature in either direction will effect the cure cycle. A change of Only a few degreer in temperature can considerably change the length of cure time. The cure cycle is accomplished chemically by l h e generation of internal. or exothermic. heat. For example, too thin a film. or a film applied 10 a ILLUSTRATION NO. 1 SIDE INJECTOR Yay b.u u d with a compnaud air or rlr-ms8lstod M o s s aptem. The advantages are separate fluids, external mixing, easy cleaning and simple design and maintenance. The limita' tions are imperfect mix of catalyst to resin, easily plugged small catalyst side nozzle orifice, and dilution of Catalyst to reduce the error in pressure dispensing. b. Catalyzed air injection system. A catalyzer Ismall pressure vessel with wly accurate rotometer) injects a measured quantity of catalyst (normally 60% strength) into the atomizing air supply of the spray gun. Resin is supplied to the spray gun with standard material handling equipment. During the atomization of the resin, the catalyst is mixed into the material to trigger the cure cycle. 91 ILLUSTRATION NO. 2 EXTERNAL MIX, AIR ATOMIZING SYSTEM The advantages are: better mix, no small catalyst nozzle to plug, no dilution of catalyst by user, and spray gun can be equipped with either external or internal mix nozzles. The limitations are: catalyzer flow m u s t be calibrated, special air hose and fittings required, and only limited quantities of material may be catalyzed at one time. c. ."Split-Batch" or double nozzle spray gun system. Two individual quantities of equal volume or resin are premixed as follows: one quantity has enough catalyst added to effect a curs for both quantities, but just enough that a total cure may take many hours or days, as long as it is not mixed with the second quantity. The second quantity has a promoter or accelerator added. The two quantities, in equal volumes, are delivered separately to a spray gun and are atomized in such a way that the two materials are intimately intermixed; the intermix. ing may occur intemally or externally. The promoter rapidly decomposes the catalyst and a cure takes place a short time later. (continued below1 prpduct. With "spray-up': a fiberglass "chopper" is used and by feeding fiberglass strand (or "roving" as it is called) thru this device. the glass fibers are broken, injected into. and deposited. along with the resin spray, to fabricate a laminate. IV. URETHANEjPOLYURETHANE FOAM GENERAL DESCRIPTION Rigid urethane foam k i n inflexible cellular plastic formed by the reaction of two liquid chemicals. a polyol and I Polyiscqnate. in t h e presence of g8s producing blowing agent. It is composed of many t h y c l d clflr. e r h con. taining the tripped gaseous blowing agent Inormally a fluorocarbon such LT R.11 or R-12).The gas contained in the calls not only s h a m the cells during formation, but also contributes special properties. such as insulating cap ibilitiM-tO the foam structure. chemical act!m ILLUSTRATION NO. 3 SPLITBATCHORDOUBLE NOZZLE SPRAY GUN SYSTEM MinuI Imarmlxlngonly shown. U u s on1 gun wlth two ilrlasr heads. The advantages are: large volumes of material can be dispensed at one time with adequate mix: no small catalyst nozzle to plug. and no calibration of equipment is required. The limitations are: premixing and precatalyzing of the materials must be done by the user; the catalyzed side of the system must be cleaned before the material cures, and a11 Catalyzed material must be used or removed during its limited "pot-life". For hand lay-ups. precut sections of fiberglass cloth or "mat" of the proper weight and weave can be impregnated with polyester resin t o form 6 Physically. the foam is 1) permanent dispersion of a gas in a closed rigid plastic Cell. As such. both the gas and the plastic cell structure contribute importantly to the foam's physical properties The cellular structure gives it its exceptional strength for low weight. Closed cell struc ture contributes to the strength and also seals the foam against panetration by liquids or other p e s . Chemically. rigid urethane foam is not a single material but a whole ctass or "family" of rigid cellular plastics bared on the urethane polymer. The control of the formulation to achiwe the ri*t form for a spacial application b *ay come @ex and raquires great tahniul cMI)mIIce. It is for t h i s "on that obtaining spacific form ProPortia for special application and cost factors, the usN should conNntly be referred to his raw material supplier. Than is 1~ me that h a greater knowledge or experience than the pmon whore "stock.in.trade" is urethane foams. He may even formulate a system just for your particular application. Rigid urethane foams can be formulated in a wide range of densities. Other types of urethane foams are classified as m i 4 g i d or as flexible. Flexible foams are produced by resting 8 polyisocynate and a polyhydroxyl material under carefully controlled conditions. Other ~semialingredients include a blowing agent and surfactants to control cell structure and a catalyst to control speed of reaction. Depending upon specific application requirements. formulations may also include additional materials such as flame retardants. fillers, extenders, bacteriostats, pigments. and the like. Also. these foams can be formulated in quite a wide degree of flexibility. The physical properties are that the cell rtrunure is broken and open, giving the foam its flexibility. Semi. rigid foams are produced by merely adding more functional resins to conventional flexible foam formulations. The ~hvsicalproperties are !hat some of the cells are broken and the blowing agent has dispersed while other cells still contain the qar. The unbroken cells, or closed cells, give the foam its semihgid structure. Flexible and semi-rigid foams are normally produced by t h e reaction of many components together at one time on a "slab4ne". Portable equipment usirq a 1:l ratio is mailable. however, the need for such equipment is limited. The Cost of formulating a 1:l ratio, flexible or semi-rigid foam system is still quite hi@. TYPES OF EOUIPMENT The first basic urethane equipment system were'designtd for flexible foam "slab" lines, pines often being4 ft. wide by 2 11. high by 15 ft. long before slicing, 8nd most of the earlier equipment for rigid foams was an outgrowth of these flexible foam machines. Today, many users of rigid urc thane chemicals a r t still using modifications of this type of equipment. When spray foam syrtems were fir5t introduced in the'late 1950s. most of the equipment was either toocomplicated or too poorly designed to be of much practical use. The equipment was much too difficult for the operator to understand or keep continuously operating, and the simple. pocrlymade equipment did not produce an acceptable finished product. The early 1960's produced somewhat better aquipment as the equipmenl manufacturers began to learn more about the chemistry of urethanes. and were thus able to design around and to eliminate some of the maintenance and plugup problems. The basic equipment which evolved was designed around the positive displacement reciprocating pump. This type of pump i s widely used to pump standard single component materials in the coating industry today. The advantage of using a positive displacement pump is that a given quantity of material isdelivered at everv stroke of the pump. In simple formulating equipmsnt. two or mom fluid seetionr are Connected directly to a single power source which drives the fluid sectionr simultaneously. By varying the length of stroka or diameter of one of the fluid sections, as compered to the other fluid section, the ratio (or quantity) of meterial delivered will change. Controlling the stroke travel of the positive displacement plunger would also have an effect on the total delivery of that particular fluid section. With Ihe proper selection of fluid section and with the stroke travel determined, tha materials can be accurately metered to be mixed in infinitely variable ratios from 1:1 to 18:l. all on one machine. Since the volume is determined only by piston and cylinder diameter and length, wear of parts such as in e gear pump, is not a factor. The repeaiability of a piston pump is constant. ChemicJl manufacturers have also helped in the simplifi. cation of the equipment by formulating their materials t o be mixed in a 1:l ratio, 8long with some tolerance in the metering accuracy. The two lor more),fluid KCtions now measure a given quantity of material with each stroke and forci or "pump" this material to the spray gun. The gun is designed so that the components, when brought together, will be mixed and dispensed. The mixing is accomplished either by baffles. surface tumbling (such as in 8 helix mixer), high pressure impingement of one r a i n component upon the other thru diametrically opposed orifice, or mechanical mixing by the use of an impeller. The dispensing of the formulated materials will be either by froth. $pray (air or "airless") or poured. depending on the type of spray gun or components being used. One basic formulator is a11 that will be required: howcver. the spray gun (or dispensins headl may change depending on the method of dispensing or atomization being bred. When materials ere mixed internally in the spray gun, any material remaining in the mixing chamber must b e purged thoroughly before the mterials have time to react ("set up"). Since moot foam systems start to harden within a few seconds, purging must be done immediately upon completion of spraying. The purging is accomplished in the gun by using solvent only, a mechanical plunger, or a solventlair mixture. The advent of m e r equipment for foam. including some changes in chemical formulations. has led to the develop men1 of very simple two component systems. These svr. tms have lightened the weight of the spray p n by r c quiring as few as only three hoses; an insulated pair of fluid hoses and one for t h e solvent purge system. The pumping system. or formulator, is designed to vary the ratio of the materials pumped from 1:l to 18:l. Inter. changeable fluid sections with different capacities are often used to vary the delivery rates. Heater5 are provided t o reduce the viscosity. aid in the mixing of the components. create uniform cell structure and perhaps produce foam with the best physical proper. tie. as well as greatly enhancing the surface appearance of the foam. The heated airless system produces the best surface uniformity or finish, as well as being the easiest of 811 sysyftemst o operate. a. I f q u i p m m t is air operated. Is sufficient air available: not only in P.S.I. but in C.F.M. 1 e. Portability. if required. sire of unit or weight 7 f. Fixed or vfiable ratios ? g. Fixed or variable fluid deliveries 7 h. Is equipment capable of handling other types of plural components ? i. I f material i s to be heated. can heaters be adapted to the equipment. ? Other two-component resin materials may also be handled with the same basic equipment design. Materials that can be best handled with these systems have a mix ratio renge of 1:l l o 18:l and must be under 100 CPS in viscosity. Heating can reduce the viscosity of the material which then can be handled with the same basic equipment. A particular system must be checked out with the raw materials supplier before heating. Most suppliers heve viscosity temperature grephs readily available. Matar wY Heatar Wt Tracing lap. f I 4l Componmt ILLUSTRATION NO. 4 Component j. Service or instruction manuals furnished. k. I s technical advice available on equipment iirequired? IfXI. by whom factory or loul representative. I.Maintenance requirements of equipment. m. Amount of training required to opeme equipment. n. Spacial instruction relating to operation of equipment. v. EQUIPMENT SELECTION - CONSIDERATtONS General knowledge of a field of endeavor is required before knowledgeable queriesan be aked. The following is a list of considerations required in selecting plural comwnent spray ‘equipment. 1. What exactly is the job at hand? 2. What type of materials are available KO do the job? 3. Who is the raw material supplier? 4. What are the end requirements or specifications? 5. What type of available equipment i s required for your particular application?With the type of equipment a t a b lished. the following must be known: Material: a. Viscosity of each component at a specified t e m m ature. b. Will material Bccept heat? e. Specific gravity. d. Ratio of resin system. e. Reaction time once mixed: 1. Cream time. 2. Rise time. 3. Tack.free time. 4. Cure time final. 1. Pot life once mixed. g. Shelf life. h. Mixirig ratio of materials. i.Number oi components to be mixed at one time. i.Accuracy of mixing required or tolerances. k. Toxicity or corrosive nature of materials. I. Curing time of material. m.Diluting or thinning of material end. if required. what percent. Equipment: a. Air or airlm atomization. spray. pour or froth. b. Required output of material. e. Required operating pressures. VI. GENERAL MAINTENANCE OF PLURAL COMPONENT EQUIPMENT Always refer to the manufacturer’s literature for prescribed maintenance instruction. Especially, pay close attention IO preventive maintenance ssction and notes. The basic main. tenance considerations required for maintenance of plural component equipment are listed: 1. Pmonnel who are operating the equipment must be fully trained in the idiosyncrasies of the equipment. 2. Follow the raw material supplier’s instruction to the letter, especially regarding the proper handling and stor. age of the formulations supplied by the material manu facturer. 3. Whenwer the equipment is used or stored for a period of time, it must be cleaned thoroughly (see shut-down procedures in manual: they may differ from an ”over. night” VI “weekend” period). 4. The system must be kept “wet” (filled with liquid) at all times t o prevent m y temaining materials from set. ing up when exposed to the atmosphere. 5. Use a solvent that is compatible with the resin mater. ials being used. Incompatible solvents remaining in the hoses or pasraga may cause partial cure or gel if not removed. 6. The equipment must not be left open to the atmm phere for any length of time LI miny materials (am ially isocyanates1 react to moisture in the atmosphere. A procatalyzed material that h r s been used in the system must be removed prior to its curing rime. Do not overlook hoses or spray gun fluid passages for cleanliness. 94 1. Extreme cleanliness and good housekeeping we a must. 8. Ifequipment has filters, clean periodically according to e check list or schedule. 9. Do not substitute standard hardware items without careful regard as to construction and pressure ratings. to. Do not interchange hoses. fittings, pumps, tanks. or rollers, otc. from one component side to another (keep "A" with "A"). Good housekeeping and proper maintenance of any type of plural componmt equipment is a MUST in keeping 8 swtm in good working order. Failure to maintain equip ment properly may lead to problems requiring extensive m i c e work which can be costly. The greatest limitation t o this type of equipment is the customer's lack of responsibility towards the equipment, especially in not deaning and maintaining the equipment. Check service manuals, or with the equipment manufacturer for his maintenance r r commendations. The peneral maintenance notes listed here will apply for any plural component equipment system rwrdless of the type of material used or the manufacturer. VI]. INDUSTRIES UTILIZING PLURAL COMPONENT EQUIPMENT ~~~~ Commercial applications of plural companent equipment are too numerous to compile a complete list and new ones are constantly being added. The materials that are used in these systems can be "tailored" to meet virtually a11 type Of conditions encountered. Some of the uses or products of plural component equipment and materials arc: 1. FOAMS-For insulation. void filling. flotation. curhioning, and packaging. 2. LATICES (LATEX) Similar to fully flexible form which is used in furniture, as sound deadenm, void filling, laminations in combination with fabrics. 3. P O n l N G COMPOUNDS For electrical components, position retention heat sinks. surface repair. 4. MOLDING Reproduction of images. model making. mass production of art forms, casting. temporary tooling. 5. BARRIER FILMS Moisture, gas. sunlight, liquid tarpaulins. weather protection. "cocooning" of p m ducts for storage, %paration membranes, shdten. 6. LAMINATIONS Combinations of materials to de velop certain physical properties. sheathing, v e n m , fumiture tom. 7. CORROSION PROTECTION Lining of chemical pro. cerring and storage tanks, protection t o the exterior of buildings and structures. marine salt resistance. 8. BUILDING MATERIALS Insulation. structural w p port, roofing, curtain wall, sound.deadening, wood imitations, interior decoration, tlooring. marine craft, sealants. glazing, joint bonding. Major industries using plural component type of equip ment and materials and their UM include: 1. Aircraft or aerospace require sealants for sealing integral components. potting assemblies. adhesives. encapsulat. ing. metal honeycomb. radar domes. leading edger and structures. heat shielding. 2. Marine Industries reinforced plastic construction in hulls and decks. Deck coatings and joint caulking, c o n struction of interior items, floatation. 3. Construction. joint seals in curtain walls. insulated windows, road or runway expansion joints. hVo.com. - - - - - - - - ponmt mmbraneJ between concrm Iaym or asphalt in hiphway bridge structure8 to prevent the imitable effects of salt. chloride, water, freeze and thaw cycle conditions. bondinp agents for drywall construction. 4. Electronics: Di-electrical insulation or barriers. create soft rubber4ke materials to a n x shock rbsorbcn, porting and heat sinks. 5. Industrial applications Plural component equipment and materials can find their way into virtually any industry. Every day new and different applications are tried or become mailable for use. The only limitations to this equipment is the people who employ it a d their ingenuity to find new a d better ways to improve their product. - VIII. GLOSSARY OFTERMS CATALYST-A substance that initiates a chemical reaction m d enables it to proceed under milder conditions than otherwi$e pouible. CATALYZER-A device for injecting a measured quantity Of utalym into the atomizing air supply. ELASTOMER-Any of various elastic substances resembling Nbber. EPOXY-A molecular.containing oxyQenatom attached to two different atoms already united in some other way. EPOXY RESIN-A flexible. usually thermosetting. resin made by polymerizationof an epoxide and used chiefly in coatings and adheaives. -A compound formed by the reaction between an acid and an alcohol or phenol with the elimination of water. K)RMULATOR-A machine designed to meter and pump materials in 8 prescribed or definite form or method. MHIBITOR-A substance that s l m d m a chemical reaction. ISOCYANATE-A salt or ester of isomeric cyanic acid HNCO Used especially in plastics and adhesives. POLYESTER-A complex ester formed by polymerization or amdensation of an acid and alcohol. POLYMER-A chemical compound or mixture formed by polymerizationand consisting essentially of repeating structuml units. \ WLVMERIZATION-A chemical reaction in which two or more small molecules combim to form larger molecules. POLYURETHANE-Any of various polymers that contain NHCOO linkage and are used especially in flexible semirigid a i d foams. elanomerr. and resins. PROPORTIONING--The relation of one pan to another or to thc whole with respect to magnitude. quantity or degree. or to mate the pa* harmonious or symmetrical. RATIO-The relationship in quantity. amount or size between two or more things or the indicated quotient of two mathemat. iul expressions. RESINS-Any of various solid or semi-solid amorphous fusible flammable natural organic substances that are usually transpar. ant or translucent and yellowish to brown in,coior. are formed especially in plant secretions. are soluble in ether and other organic solvents but not in water and are electrical nonconductors. SURFACTANT-Additive lotten a siliconel to control size. height of rise and closed cell prcentages. URETnANE-The urethane polymer involves the reaction of a polyisocyanate with compounds containing reactive hydro gens. Typical hydrogen bearing materials used include polyethers. polyesters. castor oil. simple glycols. amines. car. boxylic acids. and water. VISCOSITY-A material's resistance to flow. Methods of Application ~ Illustrated here ere the baric spray methods used for plural component application: [I] Premixed Catalyst and Resin (Internal Mixing) For small jobs which can be completed within the pot-life of the mix. Normally 1-quart cup to 10-gallon pressure tank. Suitable for frequent color change. May also be used with catalyst injected into air. Resin with Promoter, Resin with Catalyst (External Mixing) For 2- to 55.gallon applications. Recommended where one color is used. The two resins are separate until mixed enernally in the spray pattern of the nozzles. May use pressure tanks or fluid pumps. Catalyst Injection (External Mixing) For 2- to 55-gallon applications. Recommended where one color is used. Catalyst is injected into spray pattern where it mixes with resin. May be used with pressure tanks or fluid pumps. Resin with Promoter, Resin with Catalyst (Internal Mixing) For 5- to 55-gallon applications. Recommended where one color is used. Materials are mixed internally. May be used with pressure tanks or fluid pumps. Chopper for Fiberglass Layup Can be mounted on any 2-component spray gun. Chopped fiberglass is fed eaernally into spray pattern. Used to give rigidity to layup resins in products such as boat hulls, car bodies, storage tanks. etC. Externally Catalyzed Resin May be applied by conventional air spray gun or by air-assisted airless spray gun. PLURAL COMPONENT SPRAYING . FOR THE FURNITURE INDUSTRY 0 y Jury R Hund Blnks Manuhcturing Company Furntturefintshershavelongstrked for mat perfectltnishthatwillnotonlyprotea. but aecoraletheirproductsaswel~. Thecoattngmatertaisthatrostmanufacturersusetway may bethesamemate nalsyouhavecometotrust overthe years. For wood. nttrwelluioselacquerhas been Ihenumberonechotce.The benelits oerived from rnts materialhave made it number one. However.there are newer coatings oemg intrwuced to the markel Diacethatmanyfeelmllgtvenitrocellu. lose lacauera runlor itsmoney. Manulaclurers are alreaoy ustngnewer plural componentfinishes. Recent concem overtheenvironment. Coupled withthe necessity01thelintshto provide us wtm superior hardness.gloss rerentton.ullra-nolei protection.durability. ana nlgndisttnclionof image. have given the fumirure industry new challengesto face. One way IOprovlde us with these benelitsw w l d betocmstder using plural component coatings Suchas catalyzed lacauers. polyurethaneand pdyesten Toaayk popular 'wet look conststsof specally formulatedpluralcompooent polyesters.and some polyurelhanes. Regardless of the applicationlechntque usea. plural componentcoatings must be handledwith extremecareandaccuracy underthr64separateoperationsinthe 101lowingnroor. mier mix, r l i s ~ n c pPer. formingthese threeoperattonscorrectlyis thekey lo successfuipluralcomponent lintshtng. Allhougnyoucan dispensethese coatingsundera wide arrayolapplication processes.thisarticle willlimit ttsdiscusstontosprayfinishing with pluralcomm e n t materials. Regardlessofthecoatingus-. ortne specialequipmentusedtoapp~y 11.there is a fundamentalruiethatmust be closely adheredto. This is relerredto as the M-0-EPnnciple.Eachlener representsan imporlanflinktoasuccessful linishtng operation m e w representsme materia;. m e V representsmespray operator. and the 'E' representsthe equipment supplier. C m w r a m mustexist among Adnntsger and limltationr Puiseless Fluid Flow ADililyto Manole Soecial Fluids Max Fluid Delivery Rata 4s Ftela Alleraale Tywsol Alomizatlon Easy IO Operate Recommenaeofor Picductton Spraying Average Cost Eauipment Lite MechanicalGear Ralio Pumps Hydraultc/AirOperated PluralComponent Pumps YeS No No Not recommendedfor htghly Yes abrzstveorminmaterials 29 oz lmin (1 1 ratio6 14%oz of ea Comp ) Yes Compressed Ari UPIO 5 gpm Yes On Some Higher Priced Units CompressedAtr Airless Air Assisted Airless Yes. Yes Not toexceed29oz.Imin (a 1.1 ralio 54-6.000 Good lormostcoarings %Special Flutds Seciion Yes $9-12.000 Very Goad CompressedAir Pwer Source or Compressed Air Y.-L . Hydraulics .. all threegroupsinordertohaveasuc. CeSSIullinishingoperation. When usingpluralcomponen! materiais and equipmen:. excellentcommunicattons mustexistamongrhesetnree parttes., Failure ~odosowith]ustoneareamay ultimately ieaa to costiy down time. re*:%. or destroyedspray rquipmeni. Management and operatortratningIS oeb ntlelyamustwhenanempttngtospray Pluralcomponentcoatings forthe firs: m e .Specialemphasismust always De placedon proper matntenanceof me sprayequipment. Beloreyou purchase any PluralCOmpMentspraying equip ment. make your equipment suppller provetoyouthathisequipmentw~~~ pro. ndeyar with theresunsmat you areexpecting. Remember.yooarelustnotbuy n g equipment but rather resultsof what Ihat equipmentmlldoforyou. LetSbeginbya%nWnngtm,olthe mt popular systms use0today by lurmture finishers. like ywrself to properly meter. mx and dispense piuraicamp~coatings.hesewillbesystemsusrgmechanicalgear rauopumpsvs.sys!em ustng reciprccatingpumps Mechanical g a r tatlo systems (seeFig. Y1) These systems incorporateair operatea POShedisPlaCementgearpumps to ac. wratelymeterthellowofthecataiysr aW resintothe r"gcnamber.The operatorselectsineappropriategear ratdoofthecatalystandresinsupply per hs material suppliers instructions.These plm~smaybelte~OalteraDletoallowfo: amderangeofrattos. Ratiosfromtne Uylal1:l allthewayuploanexotic 14 1 raft0can be obtatned by manually chang. l n ~ m g e a r s(Srmtobereieaseo gear p a n ~ s w i lallow l lorrattochangesmthou: manginggears.)F!mratescan& con. trolled separately by varylng me speea 0: ~ a t r r o t o r t h astmultaneousty l orives thesegear pumps Apulseess tlu~oliow dupto 29fluid ounces perminuterar 1:l ratlo) IS possible.Catalprandr e m I N S 1 be force led to the gear pump underseparateflutdsuoply l r m eilner ~ m p opressuremks. i Oncethecataiystanaresin areaccuralelymetered. meymustbemtxea This lsoOne by aeltvermgbolhcomponenrs separatelytoamandoldwhtcnthen lams bahmaterialsiogetherOrcelotpeo !ne hvOcnmmnts qusttraveltnrough a hcsecontatntngastaticmlxer Theman,. e, . seclion.therattocfawnldyolmate~ats PLURAL rrJl m e . W m t l w p r o w r s e k t w d with menewpiuracomponent pumps pmdescnbed.thedtspensingor spraying tlwHutd~ionandmMlhestroketra~l of pluralcomponent ccatmgs can now be (gear ratto)pump Don1 worry abcui ma. tenal not beingadequalely mixed in the snort trave( between Ihe manifoldand nozzieotthespraygun. thestaticmixer o t w v e d totnoro~ghlymixtomcomporents together severalmilltontimesover Nowlhatlhecoatmghas been accuralelymetered and mixea it must bedispensed when usingamechanical gear rattopump.thiswouldbepertormedun. dernormal compressedair spraying practices These unitshave been successfully usea ina wide rangeollumnureappiicallOns especially 111Sliidil custom l~rusnig shops Consult thecoinparisonchart tor lurlher information Hydraulicandlor slr operated Pump systems (SeeFig. 8.2) Hyoraultc anam airoperatedplural component pumps incorporate pumps containing two(ormoreJlluidSectonstonnetted atrectly in lhne to a single power source The powersource whichmaybe hyaraulicalh,driven or an air operated pisIon anves the IIuhd seclionss i w l l a m s . ly BYvarying fhemroktngdistanceorthe volume displacement of one of me fluid sections as m p a r e a totheotherfluid deIemned. mtoltodaykplufalcun. ponBMcostingswedbylhetumituretndustwcan beproperiymeteredand aetiv. eredlo our static mixingdevice. The lluid secfionsmaybe submergeddirectly into thecoattgs orthey may have siphon hoses cwected to theif bottomslor eas. iersiphcningfrommostcontainers. Flow rateswith these pumps can exceed several gaflons per minute--more than enoughto~rateseveratgunsonaturnilurepmductionline. Themixing of these pluralcomponents isaccmplishedby pumpingthelwoma. lernais seyaralelytome maniloldana static mixer as prevtouslydiscussed.When usinghigh pressures (airless and air as. sisted airless) all fluid lines and mixing Chambersmusltefinedwith htghpressurehoses. linings.etc. As Prmslymentimed. the static mixermaybelocatedatthespraygunor althe Pump. dependingupon the circumstances.The staticmixer is usually lo'catedatihespraygunwhentrequent color charging is done as well as when usng rwdcuring formulations.Thestarc mixer ww!d be siluatedat Me pump to p w d e easier manewarability of the S P W Pun. Fig. #I Mechanical Gear Ratio Pump System accoinplisned under normal compressed air. airless. Orthe new air assisted airless spraying conditions Aswithanyspraying.8ushing 01 ail fluidlinesdthecatalyzedmafertals must be accomplished with the appropriate sol. vent throughall passagewayswhen finished To assist us.a special solvent purge tank is a necessary additmnlo any pluralcomponent system Although there areother plural comDo. mlpumpngandcatalyslmixingsys. 1EmSawallilbkthetthat have been outlined arethemst widely usedinthe lumiture induStrytOday Further informa. tion is availablefrom yourequipmenr supplier. Plura. Canwnent coating matertais have~naaedlounathemselvesapiace In the wwouormg tnoJs1ry. as weal as otner uutustnes Horrever they also present SDeCiaioiH!cultles 10 me untialneo opera. lonor users Regardiessotme piuia COmwneOlsystem you seiec: ai. muse melw mlxanoolspensemecoal.ng onlo Wrtumllun blhsystemsnaveme~r amantages MO limdalions Your c q u i p " w e r s n o u ~ o beaoie IO slwwouIkssanootners.oeaenoing mWurre.wmr"s- S t a t i c Mixer Assembly Located a t Pump Uunl S t a t i c Mixer Assembly Located a t Spray Gun .. Airless Spraying WARNING-HIGH PRESSURE-WARNING UP TO 3000 POUNDS PER SQUARE INCH DO NOT POINT SPRAY GUN AT FLUID UNDER HIGH PRESSURE CAN PENETRATE THE SKIN ANY PART OF THE HUMAN BODY AND CAUSE SEVERE INTERNAL INJURY IN CASE OF INJURY OBTAIN MEDICAL ATTENTION IMMEDIATELY BE SURE TO REPORT NATURE OF INJURY AND TYPE OF FLUID OR SOLVENT TO THE DOCTOR Be sure you understand ALL of the irutnrdm thoroughly BEFORE operaung any part of M wieu C~UDIIIM~ These innnrrions are designed as a guide for operators of Binh Airiesa EquipmenL Setup, operation, Md maintenance information b Listed to lid in w i n g the equipment in good, troubbhet cmdirim Trouble shooting chuts arc lined to J d in isolating nulIu"s that nuy occur in M &*ar pump or gun. Refer to the Rru S h m supplied with each component for speciec operotion and maintaunce inn-, w well as puu listings. 'AIRLESS SPRAYING Airkss spraying Is a method of spray applicrrion that d o e not d i r e d y use compressed air to uomize the paint or other coating m0~eri.LHydrruli p m r e b uud to uomize the nuid by pumping it u high p m (WO to lsoo psi) through a small oriace in the wmy nonlc. AS the nuid is released U thm high p w m , it b nplrucd into small droplets resulting in a very h e . or UanM spray. The nuid is discharged from a small nozzle o d c e u n r h a high wlocity that the material wan iueU md sufficient momentum remains to urry the "feponicks to the surface. Since air is not used to atomhe the material,the term " A i r W is used to describe this method. Water is hydraulically atomized.for eumpk. using the h e spray " - z n t on a garden hose no&; however. it is accomplished with low pressure be01 th low viscosity of water. Paint and other coating "rials haw 8 higher viscosity;therefore they requirr higher p r e s u r a , requiring a pump. CONSULT YOUR BINKS REPRESENTATWE TO CLEAR UP ANY ITEMS OF INSTRUCnON YOC DO qCrr Alrprnsurr ia ~ U i r r mdl y to operate the air m o m which Povrrs rrCipmcEung airless fluid pump. A pump WOFU fluid -P U a @enntio depending on s u e ofthe alr motor piston ud the effective area of the fluid pLM. E.unpL:A pump rued u 25:l.develops fluid prrwrr 25 fima the &-re applied to the air motor. For 1M)psi air prrssure,w)o p i fluid pressure muits. HOW TO SELECT AN AIRLESS PUMP Type of materials to be spnyCQ size of job, volume of air d h b k nll are considerations which g m m the x k c u o n of the pmieulnr airless pump rhpt is right for you and the muon for the wide w i e t y of pumps in our fine. When ackcting an airleu unit, answer thzsc questionr: 1. what type of material Is to be spnyed? Determining the genenl ch.ncteristiu of the materials to be spnyed b an important step “ I proper pump For light V~.UOS~~Yfluids. m a l k r orifice tips generally an desired For heavier viscosity fluids,larger ori6ce tips are prefIUrrd The quantity offluid sprayed is determined by the size of the orfbce; the thickness is determined by the o d e and the fan angle. Note that two nozzle tips having the surne oritice but different spray angles, deposit the IPN mount of paint over a different area Note that orieces are not cirdar but are eliptieal in shape. The diameters referred to ue equivalent to a Circular diameter. A good d e b to determine the !Wesf fan angle and the smallest M c e that b procriepl for your rpeclfic Iluid and applicatbn method. This indicates that a good selection of tips is required to meet all conditions. For (he majority of job conditions. only w Ups arc rctually needed. A large tip with a wide angle; ie. 92180, and a smaller tip with a narrow an@: Le. 91530. Thts type system will work and is practical Iffluid viscosity and fluid pressure are intelligently used u controls. X*ctloh Low viscosity materials n r h u spins and &quem can be spnyed with small oridce n o d s (.DO7 to .NE). To obtain the flow of heavier viscosity materials, larger ofice nozzles and higher ratio pumps are rq&. Refer to the Airless Nozzle Flow Chart below and sckct a n o d e range which is best suited for the material to be sprayed 2. How much material volume does the job rqulre? In the pressure columns of the Airkss Nozzle Flow ch.n, Ovo n U of figures are shown:An ounce per minute delivery nte and a CFM figure. By dividing the ounce per minute figure into 128 (128 ounces per you un d e t e m n e how many nozzles of a pvticulpr size can be operated from a 1CPM pump. 3. How much air should bt avaikbk? Adequate air supply for efllcient operation is dewmined by multiplying the number of nozzks to be wd by the CFM figure in the Airtws No& now Char~ulowuwr should be made for ulditiaul air opentcd .maroriea such u agiutom. ctc AIRLESS TIP SELEdtlON Tips are ackcted by theu midm size (Bo7 to .onInches) .ndfanangk(IOto80dcgms).~pmper~lcetion is determined by the fan width required for the spcci6c job and by the ondce size that will supply the ddred amount of liquid and a c c o m p l i proper amnkwbn Of the material. . n. HIGH PRESSURE CAN CAUSE SERIOUS INJURY IFEOUIPMENTIS INSTALLEDOR USED INCORRECTLY -READ, UNDERSTAND. AND OBSERVEALL WARNINGS AND INSTRUCTIONS IN THIS MANUAL OPERATE EOUIPMENT ONLY AFTER ALL INSTRUCTIONS ARE CLEARLY UNDERSTOOD. form. Electric airless units are grounded through the grounding Prong on the plug. The electric cord or receptacle must be grounded. Do not alter or m m m grounding prong. When flushing or cleaning with a combustible solvent. always use an open metallic wntainer for receiving the waste solvent. Ground the solvent receptacle. Bond the spray gun to the W e container with a grounding win. Be sun there is good metal to metol m a . Ah& r e m spay tip when flushing the airless system. Operate the pump at the lowest possible preclsure. Injection Hazard 1. The Sprayer pumps coatings at high pressure (2500 PS1/173 Bar). If you spray yourself or anyone else at close range, the stream of material can puncture the skin and cause great harm (possible amputation). 2. NEVER point the spray gun at yourself or anyone else. The tip guard provides some protection against injection injuries, but is mainly a warning device. NEVER remm the tip guard. Never point the spray gun at your hands. fingers, or body. ALWAYS keep the spray gun trigger safety catch locked in the OFF position when not in use. 3. DO NOT aver the tip guard and attempt to "blow back" fluid. This is not an air sprayer. 4. If injury occurs, see your doctor immediately! DO NOT TREAT THIS AS A SIMPLE CUT. Inform your doctor specifically of what fluid was injected. Gonenl Wamlngr 1. NEVER leave a Pressurized sprayer unattended. 2. DO NOT use fluids, coatings. or chemicals that are not comparible with nylon hoses. 3.Periodically inspect all hose for leaks andlor abrasions and tjghten all connections before use. DO NOT ATTEMPT TO REPAIR a defective hose. REPLACE it with another caductive hose. 4. Follow all warnings and precautjons of the coating and solvent manufacturers. 5. ALWAYS relieve Pressure in the system by turning by pass valve to BYPASS or triggering spray gun before disassembly of any cMlponent parts. Avoid Static Sparking Static electricity charge builds up by high velocity liquid flowing through a hose during flushing, deaning, or spraying operations. Proper grounding of the airless system safely dissipates this charge. Ail high pressure airless systems must be grounded to avoid dangerous static sparking, explosion, or fire when spraying or flushing with flammable liquids. Use Binks NO-WIRE conductive hose in all airless spraying operations. Be sure gun and hose have continuity. Check continuity weekly with ohmmeter. Overall (end to end) resistance of unpressurized hose must not exceed 29 megohm (max.) lor any coupled length or combination of hose lengths. Make sure the airless Pump is grounded. Never operate the unit when it is on a non-grounded plat- Replacement Parts The Airless Sprayer is designed to use authorized parts only. When using this pump with parts that do not comply with the minimum specifications and safety devices of Binks. the user assumes all risks and liabilities. 102 BASIC AIRLESS SYSTEMS Dead End System: Dewi end systems ue used for the majority of standard q d l t y tlnishing jobs. Y l e gun is crmneaed to the pump with a sin& hose. When the gun is spraymg. the pump delivers fluid under pressum 8d~wted by the air p m s u r e to the pump. When the gun is Mt Air S u. d . v. spraying, the fluid prruurr and .ir p r e W m UC balanced and the pump stops. The puplity and e c m y of the Bnish Is dependent upon operator Skill. fluid preplnuon and no& size. Dead end spray is usually employed with m-heated paint. I 1.Gun 2. Pump 3. Hose 4. Compressor. ekctric motor or gar engine 6. Siphon tube 6. M a t e d supply DEAD-END SYSTEM Used for the majority of standard : . quality spray Iinishing applications. Usually employed with non-heated methods. . Cuculaung System Cuculating systems are w d for h~gb qualit). producuon Bwhes. The gun IS connected to the pump with one hose. and to a pressure regulwng valve W l t h anothn hose The pump pmvides pant under pressure conunuously The back pressure r e g u b n g valve provides a constant fluid pressure and volume for the gun when sprapng When mt spmytng. the c o I u w t pressure SI SUPPb atill .Milable os che pump is rec~culaungthe pant. "he quality and economy ofthe &ush LT leu dependent upon the o p e n m r i skill or pant P ~ p a r a t ~ onnd n . IS more d o r m because of mecha~~cal consutency of pressure and volume control. Clrculaung systems are usually used with he& pnrnt , A 1 I I HOT CIRCULATINGSYSTEM M% mi*:t u 0 Producuon h s h e s where pigment senling IS a pmbkm. RecLcvlwng systems are normally employed with hot =less \ -Back- AIRLESS-ELECTRIC POWERED and GASOLINE POWERED The basic components ofan e k a r i c dnvm plrless pump are the fluid seetron. gearbox, and ekctnc motor Gembox Motu Gearbox On Enpin Clutch Control hnSUf8 bntml fluid Section 5 ORlRCL .an .w9 a11 4. 4.5 01.- .5 dm 01.- .58 d m .8 d m 6.502.- I lwo P.S.I. 600 P.S.I. .013 .015 .016 12. oz- .8 d m 13. 01.-1.1 h 14. 01.-1.3 dm .ole 12. a-1. 14. 02.-12 5, 01.- . W d m 5.7 ox.- .76 d m 8.5 ox.-1.1 dm 6.7 01.8.4 O1.14. 02.- 1.4dm 1.8 d m 2.9 dm 7 02.- 1.7 d m 10 01 2.7 d m 15 01- 3.8 d m 18. a- 3. 24. 01.- 4. 4.5dm 2602.3201.- 01.- 6.7dm 7. d m 02.02.- 7.4dm 8.5dm dm dm dm dm 29. 01.- 4.8 d m 22. +I. 34. 19. 02.-25 24. or.-3.5 dm cfm 26. 32. 01.02.- 4.2 d m 5.3 h 35. 16. .026 .031 .036 21. o2.-2.7 2tr. 02.-3.3 h dm dm 34. 02.- 6.7 d m 48. 0%- 7.4 cfm 68. 0&-11. dm 51. 02.-11. 65. 01.-14. ,043 3;. 02.4. d m 72. o z . 4 . 5 d m ~ .021 372 dm - 8. a- .8 h 6.8 01..87 d m 12. a- 2. d m 16. ox.-1.1 10. or.-2.5 22 0&-2.9 h zsw P.S.L 2oon P.S.I. 1600 ?.S.L h 01.02.- 3902.- 6.4dm 8. d m 9.7dm ~~ 32. The chan below lists recommended tips. 02.42 61. 01.-10. 112. oz.-l8. dm dm 56oz.-13. dm dm 95. 01.-20. dm dm dm 6502.-16. 8502.--21. 12601.-31. dm dm dm 105. oz-22. 151. 01.-32. dm dm icjor.--~6. ctm 1900~.--06. d m .401.-10. OPERATING TECHNIQUE Opm air ~ p p l to y pump and i m u e au pnrure at pump until putem andlor material can be obruned at the m v m. The gun should be held PERPENDICULAR d moved PARALLEL W the surface in order to obtain a unilom C d n g of mrterisl. Uneven Illmthickness and excessive offspnycan be caused by ARCING the gun. When arcing, rhe heaviest deposit of paint occurs when the gun is perpendicular to the work in the center of the arc, &d lightest at the ends ofthe arc (see below right). Arcing is caused by wing only wrist or Ioream movement The wrist. elbow, and shoulder must aIl be wed. Once the best working distance (10 to 16 inches) is determined, the spray gun should be moved across the work at this optimum distance throughout the atrcke.Snm object shapes do not allow this practice, but it should be w d w h e n m r posdble. 'Ihe proper SPEED allows a MI wet cou applleuron wuh each st&. Uthe d e d fthn thckclmcu cannot be obmned with a single stroke or p p u b e c a w of "w@ng", rtnn two or more c o w can be applied with a Ibh-off period between each,coaLThe spray movement should be at a comfortable nu. If the spray gun movement is excessive in order to avoid flwding the work, then the fluid no& wiece is too large or the fluid pressure is too high. If the s t r d e speed is very slow in order to apply full wet coats. then the fluid oressure should be increased slightly or a larger tip is required. ~~ r~ RIGHT P.rp.ndlculw SPRAYING TECHNIQUES Proper LAPPING (the distance between nmkn) ir essential in Prodwins uniformity of5im thickness. Thc 'RECAUTIONARY NOTES 'he following precautions must be observed for personpl afety and for protection of equipment Keep air compresson as far as Ieasibk away from painting are& in order to k w n the possibility of compressor contamination and to aid in keeping the equipment clean. Operating with excess fluid p r e u u m does not improve the finish. but only shortens the life of the equipment and increases wear of the spray gun fluid tip. Never attempt to remove the hose or gun before rekasing rhe pressure Iron the outAL Never w standard hardware to modify the pump. Use high prrssure 5ning5 only. The special high pressure nylon braided h w supplied is standard equipment by Binks. This hose must not be ninked. bent. or subjected to nbrasion. k d e r no circumstances should the spray gun be :arelessly handled. nor its spray @aniculnrly when the mople is removed) dvected aI close proximity to any >artof the human body h e spray paint formulacions Lo prodlre the following ondiuons: 5.mcolder thepaint particle is al it strikes me slrrface, thc mon liLely tha~one of the following condidonz can OCCIP. iapeare m rcqW,flOar-out time: inacace of solventsbciig wpped m theapplied hlm;and nmsorsags cawed by watcr king amdendinto the paint panicles cronm the surface of tbe iccm bcingSpmyaLFi. 2) Bnakdo~thecohcsivenaamofthematcrialbybwering S VkMity. Solvents cause the molpial IO be ruomizcdfiy@e m Ian). Solvents arc gemrally blended so hmost of the solvmt laptcswon Ihc paint paniclcsmch tbcstrrtace. When the paint pardclcs Rach the surface lhcy &auld here while the remaining solvenu-e thus keeping e parIides wet enough Lo &w out bm not so w a that gging occun.fig. I) NOTE. Tempfatuns m air spray penem am approximate I \ ,\! b LLV AToMmTloN EVAPORATION OF REMAINING SOLVENTS HOT SPRAYING ADVANTAGES EVAPORATION OF FAST SOLVENTS was developed to ovawme some of the pbiuns prsaiarcdwith che use of solvenu in thinning paint Hot spraying ..... fM *g. O Hcating a material to a t e m p " range between 1% Fand 16oF will pomoce conditions that can be upecud to mate thcseadvantags ROPER USE OF SOLVENTS I.cOnaant viscosity mtml of Ihe "ialking sprayed. IC~~IIUCSZ of fluauaring ambient mpaapmr. ~pmpr use of solvents can taw ccmditim which could limslcly L d to such probluns as 2Acnaateconml of thematerial umpaaMerhroughoutthe day, regardless of ambient tempaaturc. RK use of IDO many solvents can minimize film build cause the splay gun dcpsirr a fibconraining more solnu and less solids with each pass of the spray gun. ' 3.hfaMawial is thinned by heat instead of with solvents 117 If h u m fkrbdf is requirrd. then rhe mamial should bc batedjrrnMdeJihebwutwigpointofrhesolvents being p3cd in Iheblcnd In an rirlessystcm m a m i a k a heatedabove rhe w i g p i n t lo &eve fiwmmi7.ation. Check with the mataid supplier for the boiling points of the aolvenf being uscd in the material formulation. Also check thc highs! or rccommcnded tanperaMeIhe material should k hcared to. BOILING POINTS OF COMMON SOLVENTS As a guide to operating a huucd system comctly, the chan Wow listrtheboilingpointsataunosphaicprrss~ofsMne cmmon solvents used in making solvent blemk (Eg. 9 ATOMIZATION RESIDUAL SOLVENT m.0 .. EVAPORATION HIGHER TEMPERATUREPARTICLES SURFACE v i s i t y changes with the addirion of he& When only viccodty conmlis 4ougk then "tmamialw9 not have IO be h e a d above 120 F teause t k ~UICIS viwosity change OCEM before lhat point is rc&cd. (see Fig. 4) Vlacoalty va. Temperatun (Flg.4) VISCOSITY CHANGE WITH HEAT (REPRESENTATIVE MATERIALS) NOTE:Temp.raIun6 in air spray p*Hem a n approximate. TEYPERATURE IN F I18 SIX BASIC SYSTEMS 'Ihcrrmesixbuicsysrrmr which can kuscd forheatingrhe mamid or akin a spray system: l h w presswe ooncirnrlating rynun which is re"mendcd u)k used when high pmduction mes ate q u k d . the system is king used continuously. and the ma(erialdoes MI@CaLMnt C h l h I i ' a (pg. I) M 2Low pssure siphon-fed pump circularing systun with non-circulating heater is rccommcnded when mataial must be kept in cimlation or when the syncm is not usedon a continuous basis. Ihem a d is kept in heated circulation at the h t of the spray gun Warm "ing msrtrinl is mixed with cold incoming maruiaL which redmataial heating cost (Fig. 8) 1 D SLOW prcsnae hot air and heated mslaialc Jyjtcm. In this system, both the maLCrials and atomizing air m heated ?his method allows the materials U, nach h e surface ai a higher tempaaturr, which improves flowout and apparance. However, special considwtim must k given to the solvenu mdmaraialbciigd (pill) - wm"oJ~ Y(YLLDI.AL 3 H g h pressure hcactd airless circulating sysm is recommended when a fine T i is rquind and the airless proass is k i n g used. Heatmay alsobeusedtoaidin the atomization of a material which nomrally CaMot k srravcd in a cold ;system. (Fig. 119 U M Y QUN / Automatic Spray Equipment a GENERAL DESCRIPTION Automatic spray painting nuchines a n be designed to coat aimost any type of product regudlep of shape, size, color or material. The huic design of these machines will conform to one of the following type motions, excluding minor changes which m y be uud to suit the particulu product. 1. Hori2011t81 Ruiproatinp Machine This c o l t s Il8t objects such LI steel plate. plywood. etc.. which can be w r i e d on 8 Lydown conveyor u n d a the + n y gun. The motion 01 ihorizontal recipmciting machine, towtether with the movement of the conveyor, may be d s a i b e d 8s 8 series of “W’s”. The spny guns ue fked i t right angles to the surf81x of the produd. When using one spriy gun with 8 6 Inch spny pattern, the product will move 3 inches for wery stroke of the m d l n e . For a more uniform coat. an ova lap is provided to cover the pmious m o k e using one h.LI of the effective portion of the spny pattan of the prrviour strokrz The s p n y gun moves dr Lrvha prt the product and is tu& ofL The wn ir turned on six inches hefore rrutiq the next stroke. Triggering the gun helps to keep the nuid nozzle clean. Recommended for up to 25 feet per minute conveyor speeds. 2. R o t l y S p l y Machins T h e do the same bulc opntion LI a boriwntd reciprocating mehinc. but ue able to operate i t higher conveyor c p e e d ~The machine mutes at .bout 20 RPM md the spny pattan “ r a g e irr conjunction with the conveyor. covers the object wlthimiesofo~pping&he httertheuc. the more unilorm the autiog Four arm mtary rpny r m c h i w w recommended for up to 50 feet per minute. Eight rim rotary spny mehiw w recommended for m y conveyor a p e d over 50 feet per minute. A limitation of this “chine k that I t a n n o t handle i b n d v e rmteri8Is beclue of the rorrry d s it UYL 3. Spin& k c h i n a An automatic spraying system consisting of ex. bust system, conveyor (chain on edge typ)and t p n y gun controls with the exception of lo8ding 8nd unloading portion (*optional equipment). Most types of products mrted rlth thk mrhine conform to spherical or cylindrical dupes. Square dupes require two rotrtlonal u n k The object k placed on i speckuy designed workholder and routed or spun in h n t of one or more spny pnr For 8 fine uniform Ilnkh the product must he muted at l e d 8 minimum of two revolutions In the fmnt of each spny gun Depending upon the shape 8nd dsc of the pmduct, the minimum spaang of the work holder is n o d y every other pin; greater pacing between work holders a n be 8s desired. The spindle conveyor c h i n k 8vlhbk in 1-112.2, or 3 inch pitch, depending on rquhmcnts Cob veym path an be unnged to suit the indivMuai nadr *Automatie badlog and unlo8dlng c.ll he utilihed when p r k knd th&ves to rutormtic bandling. 4. Vrticll Rwiprocltlng M.chimr Dedgned to produce ivatlcll or ”up and down” stroke. These nuchines ue n o d y uud in con. junction with overhed conveyor systems, but can be ldrpted to other typc Tbe deign of these nuchiDer and controls ue determined by the size, stupe, type of nutend being rpnyed, production requirements .nd budget aibred by the customer. B. ADVANTAGES 1. Uniformity of the mating on the product 2 Cutdown ol product rejections 3. Minimum b u m elanent. 4. Paint n v l n p 5. In mort ua.production rites CUI be increased. C JUSTIFICATION OF COST 1. M.taidnving~ 2 lnurucd production. 3. lmproved product q w y . 4. RnLb unilormity. 5. k b o r IriOgL change from OM color to another. Skip spray devices are ivrilrble in order to prevent spray p m irom operating when t h m is M pmduct p m n t on the D. CONSIDERATIONS IN SELECTING A PIECE OF AUTOMATIC SPRAY EOUIPMENT 1. size and configuration of pmduct. 2. Conrryor sped-imum and mlnimum 3. Production rquhrments (to include future plus). C N m build and flnisb required. 6. T y p eofspray guns being uud. 6. Mehod Of MtRkl 1tonIhtiOn (lid€% 01 Cob mtiod). 7. Tvpa of q r r y m ~ hot spraying. : electrostatic. circulatingor dead end. a TYP 01 e ~ m ~ y ~ . 9. Conveyor dze. 10. s p n y booth rize. 11. s p y booth typcrrtcrsrlsh or dry type. conveyor. A rpechl device which has the ability to carry out rkip spray function, is a pin memory ring mounted singly or In a series. The memory ring is connected to a pamitic drive which powers a.nd movestthe memory ring In direct relation to the conveyor speed. Each ring is connected to a sensing device mounted along the conveyor. Thir may be 1 witch or a photo cell. Ar the part passes the sensing station, a signal is given to the timer unit T h k dgnal emrpizn a aolenoid which extends i number of pins in the rotating ring. For example If rich one of the 100 pinr could have a memory assignment of 4 inch= &cross the product, the ring would retain this information for a d i g w e e upto 400 i n c h a By vuing the memory assignment or using additional rings longer distances cm be obtained.Thepins, modng in Ume with the conveyor, advance to an output witch mounted in the unit. The witch is activated by the pi- and in cum, sends a signal to activate the spray gun. While this h.r been taking place, the put has been moving on the conveyor until it k in spraying posltbn at the ume time the s p n y gun is activated. Thi type of control per. mits us to s p n y when the put is in position; and we can dctnmine the approximate dupe of the put, and rcdudng w&e and "Irdenance. E. OPERATION 1. Material is supplied to the automatic spny mchina by standud pressum clnkr or pumps for mnventioml applicatiom. d lirles~high pressure pumps for iirler spraying, or where production wamnts, the circulating system is wed for supply. 2. h e spny guns cover the product with a spray pattern which is pmpendieulu to the surface. Muering thespny guns at the end ofeach stroke. overlapping at the rnmerate,andouinL.ining the proper spraying distance produces the required u d o n n l t y ofthe coating. F. LIMITATION l.Therizcudeo~tIonoftheobjedtobe mated. 2. The Nm thickness cequind in one pas though the machine. 8. (hst of the quipment murtbe justitkd in " i d avings, production incmnsz and/or pm duet unlfonnlty in one or two yeus. H.DOES YOUR PROOUCTION WARRANT AUTQ MATION? 1. High productbn r a t a 2 Slmnuity of produck S. SImetypeofrmtcr*beiiused. 4. Onlfomity rad qudlty flnisb required. G. CONTROLS 1. PURCHASE OF EOUIPMENT There is Umkcd amlog infomutiin available on autormtie systems since each unit is designed for standud components to meet the requirements of each puticulu opentbn Each rutomtic mchine is .publed on LII individual orda basis to meet the purieuhr Ipedfiatiom of the customer. The contmlr t h t are aniLble on tbac automtk s p n y machines a n be either rcmhutonutlc or fuDy automatic. "be controls an be designed to h v e thc ability to idmtify the shape rad rize of the prcduct and mat OD& Its rurfm m a with minimum over. m y . Automatic color changing unitrue av&bk to J. GLOSSARY OF AUTOMATIC SPRAY EOUIPMENT TERMS Autotmtic T a t RMI Spray Unit-A machine used to rpray pmels for hboratov uae in determini number of coats, color. sped ofappliation, etc. P-The distance between one pin of a chain and the other p i a k,bieyck c h l i ROIIW ~0nn-Apainting unit which applies 8 coating to R I with~a d e s of rollers. dmilu to iprinting a flat P= h a Sln bmcyor-Urd when the product is hmvy or not dfrupporting. R o u y Spray Machine-Spray gum are mounted on the end of urns ndmting from 8 mtni hub; these a m are a u p d to rotate at the appropriate speed and the spray pnr UT automatially triggered (used on high cpecd conveyors spraying flat work). Horizontal Reciprocating MachincA painting unit d e signed to effecl a horizontal. or back and forth. spraying stroke on flat or contoumd surfices-usually used with horizontal or floor conveyors 122 GL-RY OF AUTOMATIC SPRAY EQUIPMENT TERMS rajtic D r i v r A mech.nkd d n k thrt obWN itS w n h m some other power source. (Example: the w n to operate the pin memory ring ic obrrined from e conveyor’s movement.) Spindle MachinrA painting machine which conveys le rbn Filammt Conveyor-Widely used in the tanning justry; most nurerials used will not stick to the perlon m”e, looks similar to a a b l e conveyor. Palon Unents are used with light weight products and at r d mom temperatures only. Swl Cable Conveyor-Used mostly for sell suppo~ing product, on workholderr, prrr the spny gum which are closely controlled; the product m y be caused to m u t e to Incruse pdnting eflectivenes products such IS plywood, etc.-minimlta paint buildup. Thrw Way Valve-1s used to operate the air cylinCer of spray gun; provides very fast actuation of wrprqrpra . I Iautomatic Msmory Ring-An electm-mechanical control device 11 uses1 memorydehy principle to control spray guns, unters, conveyors, b c . I Vutiol Rociproertinp Michine-A pdnting unit similar in design to above, but p m d u m an up and down spny strokrunully used with an overhead conveyor. on d l t S which NP rt the work and pennits ah citnuhtiornormally used ere excerrive print build-up Is encountered. I TYPO Convww-Kns mOulItcd Wire M a h Convww-M#de of wire mesh to support the product ud air in forced drying. :onveyors 8k.I Cablo Used tu tarper. Self-suDPatingwan such as ~lmood. ilyurothano Belting rd for lightweight products and s h spans. ~ ire Mosh Hides solid suppal to wan snd allom air and spray to is Mrough. Useful for m w o v o n wan and when using biyumthaneBelting Wire Mesh Overhead Trolly Dual Chainwlth Cradles :e drying equipmpnt. !whoadTtolisy (All Styles) s conveyor is used exlensivelywim Bin& Vertical :iprocaling Machines. Wan is suspended f”a hook I can easily be sprayed M both sides wim tw slaggend ay machines. a1 Chain with Cradles lndrically shaped ware can be supponed a1 each end on ;e cradles to b e p wan from rolling. elc.. and pt allow iy coverage. pjcai Conveyors Supplied by B i n b ‘asSlat idely used conveyor lhal wpporls heavier ware. Cross s are Eonslrucled from wood or f a m e d sheet metal. CrorsSbt ppom ware on upright pins that am mounled on cross Is. Air can circulate around and Wneam ware. Usetul en coaling buildup is heavy. Can suppon both lighlweighl Favy ware. rlm Flhmmt ed 10 keep spray from sticking IO conveyor. Resists erioration lrom alms1all fluids. Withstands oven lwratures lo 250’ F. Used mensively in (he tanning uslry and in spraying of adhesives. Cleaning of filamenl uces the possibility of adhering 10 Ihe back surface of Pin .I. Perion Filament ware. 123 ... - Steel Cable ,. .. .... , Complete Finishing Systems 6. Air Make-up 4 70. Bake Oven 124 9. Washer 1. Bulk %tOrD00 euecrraa*wpplVyrt--Inr*d~ @mgineemd for the productkmjob requid. Thy p m a meam of doring large quantities of matefiatsWrm h &illtybQLw ofl mCrre mater*ls LI W. lhmesIa8ge tank mnge insize up to lank car cdpadly, size pwrally being delermined by lbamount of print UJed in your produclicnoperation. F"this a m the paint is pumped to a mixing room rvhem ll is thinnedto spray pinling -.These syblems meet Federal, Slate and Loul and MrpPrWd @ inWnnCe U & d D K . 2. m i n t Circulating S p t o m and MixingRoom This m a mixes and him the paint rasived from the M n g e wppty and circulatesll to the ~ t i c u a spray painting amas as nsebsd. l h locationof the Chculatingand Ming Room is " a l l y away frodthe production u wik araa Mmby meeting saakty and health requimmnts. 3. Spray Booths and Exhaust Sy8toms 'Thew Mitr meel Federal. State and W codes mgerding noise ud air pollutian. Binkt manJpautas a variety of spray bc"I ud aha& models m meet svsry quimmenL 4. Convoyom Theseam~wing~caldevic4tdesignedto" the produatromw opmatim tothe next. Due tothe wide sssu8mnt ofpmlucts. Bink mnbwusMcustcin engimemdmmyouroperatiaa ot i-"crhus~ otmxk u hirurdour dusts, mbtr. tumaa.poa hating ud M uhilum In heating plank. Einlu unfumish mndd air mkwpmitt fer Wde or outside installatiau M d fUd*trikrtion dKluork If mquirsd. Capacity ranges f"5.000 chn to 100,000cfm -ebctric. gar tired 01 seam opmt6d. 7. Botch Ovon Whatmr the applicatim-painl baking. drying, pm-heating or any omer heat proms ol large or multiple produmbatb mns can be fumishad for in and out or push-through Batch Ovens operaticnS. pmviding a smooth pcoduCki7h. am mailabkas eleclric. gar or steam types and in sizes to rawnmcdate your product. 8. Control k n o l s Cusrwn bulk factcny pro-wired end shop tested control pnels can k fumished in varioos rypeS of enclosures to meet insurance underwriters codes.Central panels am ruppW.W i n g all insbu"n¶atim mqumd. for a mmplele painl finishing system. Panels with programmable " m l s can be fumished with mitaing *ems and 8Cfwrs to indicate ompo"failures in bonderites. mns. apny boom0u l i r makbups,rvhich mducMtrouMe mooting. 9. W8ShO?S Washing and phosphatizing am usedto dean and p m p m maelsurfaces. This prevents mrrosim and increases adl"ol applii Uganic coatings to products. washers may hnn hwnhvoto six slag-, depending on you S. Dry 011 Owns Drying ia the Inuwssofsvlpaatlngwaterurohnntshg" a mquimmmb. &th gas or steam operated modelsam soli. 'Ihe Dfy on OraMm i. c " p l i his Miiabb. may bed sh.pa and sizes. *pending onthefamd 10. D a b Ovons the sosd~m k dfiedudthe am"olmpter*~ IWUJM. T h e s e ~ n s m b e ~ e d w i t h b a b s l o ~~ ~~ o v s M M ~ i n f i n i S h i n g y s l e ~ t o b r k e U Mmepmdud"ecoltinghu~appliiinthe i n g m h r l a ~ t o ( U u ~ ~ e m . ~pnyboom.Balmmum m t u m iwith mul6pk z m , 6. Air Mak04p dopending on the baking requimmem. m pru& s gacd The W k t i m d air mr)wrpsjstenmis impcd" n d d (Inirh. h n s lor indouand wtdwr instalktion, *pending pmductianlossonrmntolemployeedisamnl~pmdud QI apace mquimments am Nsilabk. Models M designed m)ectmduelodinapouvwtilalim.ud~hem larMlerebcbic.Mamugas~~. Safety Considerationsin Paint Application Introduction This discussion is concerned with a painter's need for safetyq u i p ment when applying paints and protective coatings. Binks Bulletin PE--Protective Equipment" h a recently k e n revised and updated. and presents the entire line of safety quipmcnt mukcfed by Binls Manufactunng Company for UTC by painters and applicators of multi-component coatings. 'Ihis bulletin presents rhe protective equipment and appml recommended for different methair of surface preparation and for different types of coating application. which OF cannot escape without pmpr respiratory protection. Air-supplied respirators offer no protemw if the air supply fails. 'Ibc quality of air used in air-line respintor systems is very impor. um. l@c air contained in a cylinder or supplied by a compressor must k Gnde D air or kucr. as defined in ANSI Standvd 286. I 1973 orCompreswd Gas Assciation Specification G-7.1. Grrcndy. Grpdc D air shdl not. conuin more than 20 pyls per million wrbon monoxide. 1.W p y u p r million wrbon dioxide. ad 5 milligrdms per cubic meter condensed h y d " s . If the fnsh air which is i n d u c e d into M oil-lascompressor is of this q d i t y (and this should k the CJK unless h e inlet air is grossly ccmuminated). the delivered air will be of qual quality kcause no CCIuminan~~ arc added as the air passes through the compressor. W& oil-lubricated. piston-typ compressors. overheating may pmducc carbon monoride. so routine testing for carbine monoridc a &e inswllation of a constantly monitoring analyzer is q u i d as well as a high tempennut alarm on Ihc compressor. Alnp know the contents d t h e coaling materials being used by referdog 10 Lbc M.lcrll s.tetY Duo Sheets (MSDS) SUP p k d by pur m(CIws ~ p p l i u . lk l l " l d Limit Values' for yvenl chemical rubslvlm ue pocnlcd in Tabk I. ?be aliphuic solvents. such as mineral Ipirmad ruphlhr bve a'hw ndcr of toxicity in the m g c of MD 'vp million Ihm may k inhaled in an eight hour day. Stmaw solvents quircd for h u v y duty m t i n p . such as the keto& and UC I " a U c rdvmn (toluene and xylene). am much mm toxic, and are listed in Table 1. 'Ibc toxic cffcnr from ovncxponm to pain1 solvents IIC presented in Table II. UdOrmamly. LIE most corn"s m g paint solvents such as the MrmdcI Ibc b d chain kmoocs, rrichlacthylene and diaceto^ alcohol LIC phocochuaictlly rwnive. Pam solvents may only coolpin up lo 20% ldum 8 4 x y k 20% methyl isobutyl kc1~1~.a2(#,uichl~yhnc lk noo-rrrcdve solvents include atm. alcohols. the aliphatic ud nrpthcnic hydraubons. lad methyl ethyl ketone. All major paint companies lhrmghout the United Sutcs arc nou active in fOrmUhtIng notbrcrctivc solvenu which will have solvem powm and evaporation rates similar IO the currently employed photochcmiully runive solveno. "on-reactive solv w m gencnlly COfnpovd of blends of different esiers. .ccwr+. cmpler Ilcohols. and naphnic hydrocarbons. At this point kt's examine five major reguhton. agencies thai i n om way or another affea h e spray fuishinp opention. - Hazards The followinn discussion reviews the different huydr involved in the application of protective coatings which make. protective equipment and apparel ncccsury. Several principal hazards are involved in the applicatton of pnu. Toxicity CM OcNr due to tnhalotion. absorption. or ingestion of the solvents into the bcdy. Also. many coatings which are U-V curable will uusc bums to the skin if not handled properly. There is a r " u m allowable conccnmtion of subsunm that can k inhaled in an eight hour day without danger. The American Confmnce of Govanmmul lndusuial Hygienislr has determined the safe mnanmcion of LIE various subrunces. ud pmeno lhir coacmmtion in teams of pans per million by volume. For m y spray f i g opndonr a s o n d v d paint spray rcspima will pmvide pmcccdoh Standard respirators y x chemical umidger and sepvprc prc-fillcn to m p don. mists. ud dust g e m a d by painting opentions. The NIOSH/MSHA approval for lbesc rrrpinms coven mists of paints. Iacqum. and enamels. up to loo0 pans pr million of organic vapoo. They arc .tso appmed fame in dmu ud mists having a TWA (time weighted avenge) of m less thu,0.05 milligrams per cubic meter or Iwo million particles pr cubic foot. Rcspinton designed for protection against asberm conumioption arc also available. These may be used by p ~ wdoing l asbestos encapsulation. D i i m c p " a which am round in urehm paints. have a low odor lhrcshold. Thlr means that a dangerous k v d ofdiLocyanates can break through tbe charcoal Inside tbe chemical canridge before the painter k able lo smell i t If the paint contains diisocyanaies or the paint vapors ex& the IMX) ppm limit ora chemical cmridge respirator. the painten will need air supplied to them from an outside source. Thus standard paint spny respintors are not recommended for urethane paints or other. paints containing diirocyanates because of their poor warning propenies. This means an air-supplied respiratormust k used. Rcwntly. IhUc arc two ouiside air sources: a compressor h a t supplies sir conunuwsly to rhe air-fed respirator or a large cylinder of compssed air that supplies air to the air-fed respirator as Ihe w w l c ~inhales. Be aware that both cartridge-type and air-supplied respintors have limitations. They must never be used in u w s where there IS less than 19.5% oxygen. where the conuminants arc unknown. are immcdiaicly dangerous to life and health. ?r from EPA Environmental Pmttaioa Agency The EPA's objective is to reduce the a" of paint solvent exlnurted into the atmosphere by industry. They also want to rrduct or eliminate the discharge of ccnain chemicals in waicr. l k r e we five classes of pollumts IhJt EPA controls: 126 ~ ..-..... m n Monoxide CO Sulfur Dioxide._".._.......SO? Suspended pyliculuc Nitrogen Dioxide NO? photochemical Oxidants 0XOronc) ,-o. 502. and NO? are basically products of combustion. Hydmarbon(solvent) emissions fmm finishing opentions are considered photochcmicdly oxidizable and therefore pmdua Ozone is alleged to impair the function of the lungs Jnd to induce respintory illness. Orone is also reputed to hinder plant p D ~ t hand bring about changes in wildlife habitat. Existing emission regulations and implementation procedures v3r\. widely. However. all future planners in the finishing indusshould remember that unregulated discharge of organic solvents and pmiculate will not be allowed. In addition. waste water from spray booths will require special treatment 10 remove inorganic as well Y organic chemicals. WT Dcpnnment of TranrporuUan DOT h v m tha materids mnsponed on public thoroughfares are a ~ l packaged y and clearly identified. Specific infomution about the murid and its hazard propenies mu1 be on the psckage Lbel and the shipping pap% .......-.. ' OSHA Oecupatlonal Salet? and Health Administration OSHA's goal is protection of the health of workm. One of OSHA's accomplishments has been an increase in the general RPmmabillty and Exploslve Limit We ye c o n m c d with two types of fire hazards: Flammability and the likelihwd of an explosion. Flammability is determined by several mcthodr. but for painters. the "Open Cup" method is most significant This method dercrmines the tcmpenture of the solvent which must be reached in an open container before it will *ucb fm when a flame is applied. Generally. the more volatile the solvenr rhc lower Ihis tempenntre will be before it will catch firr The m n g solvents. such as xylene. toluene. and the ketones ate very votuilc and h f m very flamnublc. 'Ibc likclihwd of any explosion with any solvent is dependent u p Ibc c " m i O n of the solvent vipcns in tbe atmosphere. If the c m x n d o o is UK) low. h u e is ux, link of rhc solvent prcwntto explode If lhis concamtion is 100high. no explosion will OCCUI because of lack of oxygcn. lkrefore. them are two limits of conanadtion bervecn which explosions m y occur. and cbae are "ed the "bwer Explosive Limit" and the "Upper Explosive Limit". I"s.of come. uc concerned only with the lower explosive limit The h m b i l i t y and explosive limits of various solvents at presented in Table 111. Bwarencss of the chemical composition of coatings. Each chcmi:a1 compound in a given coating must be considered for its par. iiculu impact on the physiology of mn. Possible toxic pmdunr resulting fmm chemical inreramions of the mating with orher agents or ingredients must be considered. New coatings must k bmulatcd with sensiuvity 10 potential shon-tmn ud long-term umuhrive haznrds. Ofspecial concem is h e cumutuive effecl if breathing solvent vapon over extended periods of lime. kquiremcnts for protection of workers exposed (o a known or u ~ p e dl"dous environment mu11 k pur of tbe fd :lese considmuons when commercializing new couings. lCR4 R n o u m Conservation and Recover?. Ad his am regulates chemical wastes f" the point of generotion 10 IC point of disposal. The following criteria are tbe I;cy elements I classifyinga chemical waste as hazardous: !nitability- Rash point less lhan 140 degrees(Pensky Mmcns closed cup) orrosi!ityPH of 2 or less OT 125 or more-Any subswce exhibiting corrosiveness not orhmviw l i t 4 as Rae111 Lqidation and Air Pollution Control Considerations The South Coast Air Quality h g e m n t Disuict (SCAQAIDi rad h r EPA agencies. uc conamed with the quantities of phol&"dly reactive solvents h a t may be employed in p i n t s which are sold in mntainm larger thyl one qwn. The recently dClean Air Acf now limits the u x of V.O.C.'s (Solvenil in coatings. Check with your local EPA authority for a cumnt list of prnnissiblc formulations. The photochemically reactive solvents. unfonunmly. arc corn. mon strong paint S O I V C I S such Y the yomatics. the bnnch chain ketones. mchlorethylene. and ducctone alcohol. Paint solvents may contain up 10 ?G% tolucnc. 8% xylene. ?OS methyl isobutyl knonc. or 20% uichlorethylcnc. The non-reactive S0IVCI)tS tncludc cstm. alcohols. aliphatic and naphthionic hydrocarbons. and methyl ethyl ketone. All major pint companies lhroughout the United Sute arc nou active in formulating non-reactive solvents which will have rimilu solvent powen and cvapmtion n t c s as the cumntl! employed photochemically mactive solvents. Son-reactire solvents gencnlly are compowd of blends of differeni cster~.pn. nurily acctatcs. COmpkX alcohols. and naphthionic hydmubvnh. hyydous Matcrial~readily capable of chemical runion such that they prexnt a danger to h u m health and environment itnction Procedure Toxicity-Related to ability of a chemical waste to r e l e ~ etoxic chemicals in the presence of water. ,me common paint solvents and solid ingredients are listed as zardous wastes. For t h i h reason. all paint formulations must be refully reviewed as to the composition. classification. and dissal of their manufactunng or end-ux residues. :activity- iCA Toxic and Substances Control Act ;CA requires that the new chemical rubswnces be thoroughly ,sed for toxicity. cucinogcnicity. CIC. Chemical manufactum J processors will be required to provide proof that new materido not pose significant risks 10 h u m health and the environ'nt. Tnis concern arises from the estimates lhat one out of every ir Amencans dies from cancer and thnt90E of all wncm result m cspsure to agents ongtmttng outside the humn body. invat!on on paint systems has evolved through lhc mntinuous relopmcnt of neu chemicals and their associated economics. Cumn; DOT regulafions set the following criteria for hazardous mterials: Flammable liquids Combustible liquids Poison B Comsivu Flammable solids DOT NICS prescribe the type. quality and handling of coatings pachgcs. They funher identification of the gcncnl huard prop enics of the material and. depending on interprewtion of other federal and sme laws. a fairly specific identification of drum contents and accident management insuuctions. Thcx costs must also be considered by the coatings chemist. 127 ._ TABLE I MAXIMUM ALLOWABLE C( #CENTRAT SS OF SUBSTANCE VAPORS Chemical Substance Chemical Substance nv* Acetone AlCOhOlS ..................................................... .......................................... 10 ............... 0.02 .......................................... 50 ........................... 200 ...........0.2 ............ 50 ............................................ 25 € t h y h e Dichloride 750 ...................................... Ethyl (Ethanol) Isopropyl Benzene (Benzol) Carbon Tetrachloride (Skin) Chlorobenze Chloroprene Chlorotoluene Methyl Cellosolve Acetate (Skin) Cyclohexane Cyclohexanone Cyclohexene ................................................. ......................................... .......................... ........................................... ............................................. Methyl isocyanate (Skin) Methyme Chloride Methyl Emyl Ketone (MEK) Methyl Elhyl Ketone Peroxide (MEKP) Memyl Isobutyl Ketone (MIBK) Perchlomthylene io00 . 400 1 5 ............................................. 10 .............................................. 10 ........................................... 50 ...............25 ........................................... ~ 0 TLv' ............................................... 50 ................. 0.005 so .................................. .......... 100 Tolutloe CTOluol) Toluene Diiswanate TrichlomWene Turpentine Xylene (Xylol) 0 ................................................. 25 300 100 TABLE II TOXIC EFFECTS FROM OVEREXPOSURE TO CHEMICAL SUBSTANCES Chemical Substance Effect of Inhalation ... Acetone ............................................. Alcohol. Ethyl ..................................... Alcohol. Isopropyl Benzene (Benzol) Carbon Tetrachloride ......................... Ethylene Dichloride Methyl Ethyl Ketone (MEK) Methyl Isobutyl Ketone ( MIBK) Nsphtha, V.M .+P Toluene (Toluol) Trichlorethylene Turpentine Xylene (Xylol) .............................. .............................. ............................ ............... ......... ............................... ................................ ................................. ......................................... .................................... Irritating to mvcous membranes: choking sensation Intoxication Intoxication: . headacta Injury 10 blood-forming organs. and to hean. liver. kidneys, etc. Nausea. headache, vomiting: injury to liver (nephritis) lnitating to nose; retching; unconsciousness Initating to nasal passages: choking sensation Initating lo mucous membranes: choking sensation h a m e : vomiting; muscular twitchii Same IS for benzene except llttle damage to bloodforming organs Simiiar to carbon tetrachloride; disturbed hean a a i m Irritating to nose and mmt; headache: vomiting; stomach pains Same as ior benzene except little damage to bloobformingorgans . TABLE 111 ~ ~ ~~ ~~ FLASH POINTS AND FLAMMABLE UMrrS OF CHEMICAL SUBSTANCES Chemical Substances ............................................... 1 Acetone Alcohol. Butyl ...................................... Alcohol. Ethyl ...................................... Alcohol. Isopropyl................ ;............... Benzene (Benzol) ............................... Carbon Terrachloride .......................... Cellosolve. Acetate ............................. Cyclohexane ....................................... Cyclohexanone ................................... Cyclohexene ....................................... Ethylene Dichlonde ............................. Methyl Ethyl Ketone (MEK)................. Methyl Isobutyl Ketone (MIBK) ........... Methylene Chloride ............................. Mineral Spirits I ..................................... Naphtha. V.M.+P. ............................... Toluene (Toluol).................................. : 1.1.1. Trichloretnane ........................... Tnchlorethane ..................................... : Turpentine ........................................... Xylene (Xyloll ...................................... . Average Explosive Limits,' 7 by Vol.. Approximate Boiling Point Flash PoinI LEL UEL Range, Deg. F Open Cup, Deg. F (Lower) (Upper) 132-134 0 240-245 173-176 115 55 53 12 178-180 174-176 170-172 293-313 179-182 303-313 180183 179-186 174-176 237-246 104-105 307-389 212-320 230-232 165194 188.190 307-347 281-291 2.6 1.5 3.3 2.0 1.3 22 - 56 21 73 6.2 1.8 1.4 15.9 10.0 7.5 117 32 111 None 104 45 40 None None 95 81-115 1 12.8 11.2 19.0 12.0 1.1 -- None i Non-flammable 1.7 1.3 - 8.0 Non-flammable 6.9 0.9 1.2 7.5 6.0 7.1 I i i iI I 1 Non-flammable i 8.0-10.5 ! - 0.8 None 1.1 7.0 1 GLOSSARY OF TERMS nrrh Point*- the minimum umpeniureat which a liquid gives off vapor within a test vnxl in sufficient con:entration,to form m ignitable mixture with air near the Surfm of he liquid nnmmoble Liquid- any liquid having a flash point below 1mF and having a vapor pressure not exceeding 40 p i n at IOOF. Combustible Liquid- any liquid having a flash p i n t at or above IOOF. Ignition Temperature-the minimum temperature requid 10 initiate or uuse self-susoincd combustion. Lower Explosive Limit ( L W - the minimum concentration of vapor in air or oxypen below which propagation of flame doer not occur on contact with a smmt of ignition. Upper Explosive Limit W E L k the maximum concentration of vapor in air or oxygen above which propagation of flame does not s c u r on Contact with a 10urcc of ignition. nammnblr tExplosivet Range- the range of flammable vapor or ya5-air mixture between the upper and lower flmmblelimits. \APOR DEXSITY- the weight of a flammable v q " compared to air. .4i1=l. Vapors with a high density arc more dangerws and require kncr ventilation because they lend to flow dong the flwr 2nd collcct in low spots. 'flash pin1 is n o m i l y an indication of suwcptibiliry to ignitioa. Howew. in finely divided form such Y mist o( s p y . liquids csn be ignited at tempentum klw their flash poinrr. As in mC case of vapors. a minimum concentration of dmpktr must bc pnsent IO suppon combustion 12Q TYPES OF RESPIRATORY PROTECTION Many o p e r a t i o n s a r e performed i n a f u r n i t u r e p l a n t t h a t r e q u i r e r e s p i r a t o r y p r o t e c t i o n . Among t h e s e are (Upper L e f t ) t h e c l o t h f i l t e r s , f o r p r o t e c t i n g a g a i n s t suspended s o l i d s l i k e sawdust. These are n o t recommeded f o r use when s p r a y i n g s o l v e n t based mate r i a l s . Charcoal f i l t e r r e s p i r a t o r s (Upper Right) a r e used w i t h most s o l v e n t based m a t e r i a l s l i k e l a c q u e r . These f i l t e r s must be r e p l a c e d when t h e s l i g h t e s t o d e r s t a r t s t o p e n e t r a t e through. The a i r f e d r e s p i r a t o r (Lower L e f t ) i s r e q u i r e d when t h e contamina t i o n w a r r a n t s s p e c i a l p r o t e c t i o n . Most c o a t i n g s c o n t a i n i n g harde n i n g a g e n t s w i t h t h e v a r i o u s forms of I s o c y a n a t e s r e q u i r e t h i s form of p r o t e c t i o n . The A i r Fed Hood ( L o w e r Right) p r o v i d e s t h e sprayer with not only a fresh a i r supply, but protection for' h i s e n t i r e face. i n addition t o the I t ' s n o t o n l y t h e moral t h i n g t o do, A 1 1 of t h e above d e v i c e s should be c o n s i d e r e d s p r a y booth a l r e a d y i n u s e . I t ' s The Law! 130 Paint Curing By Infrared Catalytic Thermoreactors New EPA standards for Air Quality Management are mandating changes in the types of coatings being used as well BS how they are applied. Newer coatings now require higher temperatures to achieve full cure. The standard method of curing industrial coatings has been accomplished by slow open air drying or somewhat faster gas heated convection air ovens. Electric infrared has also been used for curing paints for certain applications. While enhancing the rate of cure, the energy costs become excessive to operate. The introduction of gas fueled infrared catalytic thennoreanon is changing the way industry is curing organic coatings as the following account describes. S U 8 s T R A T E WHAT IS INFRARED Infrared is a part of the ELECTROMAGNETIC SPECTRUM of enem.lnfrsred b an invisible radiant wavelength of energy between 0.07 and 1,OOO microns (a micron is a unit of length equal to O.oooO3937 in. 0.001 mm). It lies just beyond visible light to what b called the red side of the radlant spectrum. Visibk light displays a spectrum of colors from violet to red. The wavelength range of visible light is 0.4 microns on the violet end of the spectrum to 0.7 microns on the red end. All materials are affected by infrared wavelengths. This is identified u ABSORPTIVITY.and each material hn?, a wavelength range of maximum absorptivity. There are charts available to determine the absorptive wavelength for almost every material. ‘zzwail”mutawdor c8wk4p. )slur b nllrw b n k Inndidhll pr*lar bm”lol.wbor I .*rr)rEdbtb. 1YI a c u m h i o h d l “ogb~dpkfp*l(ilr so. or ”# ~ . m ~ ~ ~ * ( a n r b n t tm ~t~ wa ~hl p t u . lam*&nrwa. precisely the wavelength mge emitted by fhe catalytic thennoreactor. AU paint, varnishes, and industrial finishes contain these organic materials and each of these organic materials readily absorb the infrared emissions in the range generated by the catalytic thermOrepaor. Substrates, however, do not absorb the infrared emissions a s efficiently in this wavelength range, they reflect them instead. A coating of paint on a substrate is doubly ailected by the infrared wave. The wave &t passes through the coating of the organic paint to the substrate and is then reflected back through the paint. Several benefits result from the physics involved in this process. First, the substrate being coated does not have ‘io be heated to cure the coating. The finish is heated through molecular exitation Srom the infrared wave which causes the coating to cure from the substrate surf a n out. A major benefit of this method of curing is the prevention of skinning of the coating’s outer surface and its subsequent “pinholing.” EMISSIVITY is the measure of the infrared wavelength that an infrared device produces. AMPLITUDE is the power that the infrared wavelength is produced and its effective focal distance from the infrared device. Every substance has a speci5c infrared absorption spectrum or wavelength. This wavelength is the one most readily absorbed by that substance. The absorption of this wavelength by the substance increases that substance’s tempetacure. The specific infrared absorption spectrum for an organic coating (paint) a r e the wave. lengths between 3 and 10 microns. This is 131 Paint Curing By Infrared Catalytic Themoreactors New EPA standards for Air Quality Management are mandating changes in the types of coatings being used as well as how they are applied. Newer coatings now require higher temperatures to achieve full cure. The standard method of curing industrial coatings has been accomplished by slow open air drying or somewhat faster gas heated convection air ovens. Electric infrared has also been used for curing paints for certain applications. While enhancing the rate of cure, the energy costs become excessive to operate. The introduction of gas fueled infrared catalytic thennoreactors is changing the way industry is curing organic coatings as the following account desaibes. WHAT IS INFRARED Infrared is a part of the ELECI'ROMAGNETIC SPECTRUM of energy. Intrared is an invisible radiant wavelength of energy between 0.07 and 1,OOO microru (a micron is a unit of length equal to O.oooO3937 ln. 0.001 mm). It lies just beyond visible light to what is called the red side of the radiant spectrum. Visible light displays a spectrum of colors from violet to red. The wavelength xange of visibk light is 0.4 microns on the violet end of the spectrum to 0.7 microns on the red ad All materials are affected by infrared wavelengths. This is identified as ABSORPTIVITY.and each material has a wavelength range of maximum absorptivity. There are charts available to determine the absorptive wavelength for almost every material. EMlSSIVlTf is the measure of the infrared wavelength that an infrared device pmduces. MlPLlTUDE is the power that the infrared wavelength is produced and its effective focal distance from the infrared device. Every substance has a specific infrared absorption spectrum or wavelength. This wavelength is the one most readily absorbed by that substance. The absorption of this wavelength by the substance increases that substance's temperature. 7he specific infrared absorption spectrum for an organic coating (paint) a r e the wavelengths between 3 and 10 microns. This is - F M1 blnmdndlrtlol. a a n a r * t h ~ a K . p t n r ~ t h n i p l Nnm m d lanktad ba&. b W q to. ma gwulma" Imlr(tbb ml1111 aollabadmb. l m rHoa tmrradnau m*r.hp*(anrbathW& W L h WtA b "gh LOIMldW". precise& the wavelengfh mnge emitted by the catalytic themoreactor. All paint, varnishes, and 'industrial 5nishes contain these organiC"& ' and each of these organic materials readily absorb the infrared emissions in the range generated by the catalytic rtrennorelcw. Substrates, however, do not absorb the infrared emissions as efficiently in this wavelength range, they reflea them instead. A coating of paint on a substrate is doubly affected by the infrared wave. The wave Brst passes through the coating of the organic paint to the substrate and is then reflected back through the paint. Several benefits result from the physics involved in this process. First, the substrate being coated does not have to be heated to cure the coating. The finish is heated through molecular exitation from the infrared wave which causes the coating to cure from the substrate surface out. A major benefit of this method of curing is the prevention of skinning of the coating's outer surface and its subsequent "pinholing." This is the distinct advantage in furniture finishing, automotive finishing and refinishing, and nul ierous other industrial applications. Cor {entional paint curing methods, such as in a hot air convection wen, the coating film dr ,es from the outside and skins over before internal curing is completed. When. as curing progresses, trapped solvents eventually escape, they must break through the already partially solidified surface, leaving pinholes and craters. It is the presence of these pinholes, in all sizes, even microscopic, that renders a &ish dull and rough. The Merence between drying the surface of the coating and curing the entire Elm is that when the Blm is cured, it can be sanded and rubbed to the desired degree of finish. The surface dried coating is dry to the towh only and may take hours or even days before final cure sets in. THE CATAWnC THERMOREACTOR The catalytic themoreactor has been d e veloped to generate infrared using natural gas or propane gar in a most etacient manner. The thermoreoctor employs a special catalytic pad to sustain a continuous reaction between the gas fuel and oxygen out of which infrared radiion is anitred. The thermoreactor is a flameless. catalytic oxidation of the gases used sfuel in the system. Catalytic oxidation will only occur when the proper proportions of oxygen, fuel, and heat are brought together in the presence of the correct catalyst. The thermoreactor system provides the means of producing the appropriate environment for the catalyzed oxidation to occur WXkr Stringent control to be inherently safe. The thermoreactor uses an electric resistance coil inside the catalyst pad to initiate the preheat condition required to raise the catalyst pad temperature above the point of safe catalytic oxidation. Once the internal control veriees that the temperature has been met. the electric resistance coil is turned off and the gas solenoids arc opened to releas? gas fuel Lo the catalytic pad. where it is oxidized. producing the correct wave- natural gar ir Mxed wlIh u* rutmon(hg air ol1* ana( WW. II l l n n t C t S C M l b W l M ruciiOnl i b 5 @JCB rlthtp t* IbvmON8dW'S ClblVlk Pld. In &&lk k l U q #~KICII inside the memmrclorr crliiflic ued o m m r 1*w m m hr the alalflis 01ld~llm. (Pinholing is caused by the fast evaporation of the solvents through the "skinned" Outer surface of the coating.) The curing occurs from the inside out and the outer layer remains fluid while the inner layer of coating proceeds to cure. Solvent is forced from the suhstrate level to the surface of the coating and evaporates through the outer film. When the outer surface has finally cured, all internal solvent has since escaped w d none is left to break through the skinned over outer surface and leave a blemish. Infrared cured finishes have a higher gloss appearance than coatings cored by conventional methods. 132 4. Versatile controls prwide total operation- kngfh of infrved used for nrring. Ihe thennoreactor does not have spark plugs, ignitor points. or open ilsmc within the system lf, for ai flexibility. 5. Saves space, time, and energy, up to 90% fuel savings compared to bake or convection ovens. any reason, the temperature of the catalytic pad does drop below the safe operating temperature, the intemal controls will aut* matically shut the unit down. Any power failure will also automatically shut the entire system down. The optimum fuel flow for the thermore'actor is fixed by the inlet orifice diameter and the gas volume supply pressure. The necessary oxygen for combustion is provided by the ambient air drawn through a venturi, along with the incoming gas. Secondary combus tion air is provided by a forced air system which propels the air across the face of the catalyrc pad. The catalytic oxidation reaction is totally safe. In fan, solvent can be squirted into the catalytic pad, when it is operating, without ignition occurring. This is because the oddation reaction is so rapid, that the volatile ma*erizl is consumtd before It can ailtoignite. The thermoreactor is approved by Factory Mutual for use in spray booth curing systems as a separate operating cyck. The interlocks on controls will prevent using the spray booth for both painting and curing at the same time. The advantages of catalytic thennoreaction in fostering good community relations by minimizing air pollution and in reducing insurance costs by virtue of its inherent safety, are readily apparent. -re are, in addition. other advantages relating to installacion and operation costs, and improved product quality. Some of these are: 1. Require minimum venting with fans since thermoreactors safely oxidize solvent vapors that come in contact with the catalytic disc. 2 . Units d o not have to be covered up like quartz tubes o r lights in a spray booth. Any dirt. dust, or overspray which accumulates on them is burned off safely. 3. Units can be retrofitted into an already existing spray booth, thus avoiding the need for additional space. 6. The high temperature units can be used in industrial drying painted metal panels, fabrics, leathers, etc. 7. Due to the very narrow range of the infrared radiation, many substrates never get too hot to handle. 8. Rovides proper curing temperature and does not overcure or cause color change totheBlm. 9. Drives off solvents and redicing blushing, solvent popping, and skinning. 10. Highly effecrive on acrylics, enamels.alers, lacquers,polyurethanes, and putties. 11. Reduces risk of dust and dirt contamination because there is minimal air movement, only 10 standard cubic feet per minute per head. Special high temperature catalytic units are available for industrial application. Selection of these usually is based on results of tests performed with the actual product which evaluate the degree of radiation absorbed as well 8s heat losses due to convection, radiation, and conduction. Radiation absorbed depends on distance between work surface and themoreactor part shape (hidden areas, etc.). type of coating (resin. solvent amount, etc.). * Heat loss through convection occurs when cooler air sweeps over a warmer surface, extracting heat from it. Radiation loss is the heat reflected from the work surface. Conduction loss is where hcat transfers to a colder body (substrate) that is in direct physical contact with the heated body (paint Blm). I t depends on the thickness and nature of the substrate. Thin metallic substrates conduct away less heat than do thick ones because they offer less of a heat risk. . 133 I r SOME CONSIDERATIONS The catalytic disc requires an electrical re sistance wire to bring the disc up to temperature before the self-sustaining catalytic reaction takes place. Approximately 10 amps at 120 volts are required for each disc. R e a o Cion temperature is reached in only a few minutes of time. After that, electrical power input is not needed The units are provided with individual fllten to ensure that clean air for combustion reaches the catalytic surface. Filters should be changed after approximately one month's operating time. All in aU,the potential benefits of the Cacalytic Infrared Curing System are considerable. With today's need for energy conservation and pollution control improvements, I t is heartening to Bnd a produst that answers so many of the concerns of the painting and tlnishing industry. Not only are these systems economical to operate, but they also reduce the time it takes to cure paint and finishes. When in use, Catalytic "hermoreactor Curing Systems are safe to operate and are noted for their long life span. Finally, the versatili*, of these systems in curing various types of coatings i s excellent J spray booths udm which effect yap uea to determine the type of .prry booth9 thu M.mprpble: A DRY TYPE SPRAY BOOTHS: Dry type spray boo* ue chcse that usc a mechanical muru to distribute the dr m-nt e n l y ud PIP vide proper Oltration when rquled. No water is re. puirrd for fflhation HWMT.In so"areas,water may be rquired in the .rufor 5 e protection or clean-up. 1. Blllle booths-an the most fundamental type. W e plates are used to distribute the flow ofair through the spray u e a and prevent some of the mild puticles from belng erhPuJted intn the air. They g e n e d y ue wn in applicnrions where m a U spraying operations fake place i n m i t t c n t l y md the dlschwged lir d o e not have tobe h of paint putid= 2AdvyuagaofbalUebooh rmffincoa b. B.(Beo are designedtopmvide uniform air flow through the booth and elimlnam some of the *dningputicla c ughtinweigtaiflkorlodlngLnaprobaL - dSuiuMefaaWithm@lypaof"teri.l e suiuble f a llmlted production where Bemnlly not more tlun two gauons of paint ue sprayed w, PI vith d o s e d booths. t LnrteonofirSulb3 'n C NoawrepLfanaurrpul.cd B ~ o l t 3 o f b a m e ~ L Limited tllpulon of minute plint particles. b. 8" . must be stripped when'excess paint YEumULtcL c Dmignedtohpndkonlylimitedprcduction dCmnothrndk9murnols--oprotcsbesl with .lovdlyingMtcrLLr. (.%e Rge I 4 tor ulrrmotion.) I). RLTER TYPE SPRAY B m : When selec~nga spray booth,It k dnuble to check the adety, flrr, insunnce, underwiterr ud kuilding 'B~SpnyBoothrWormmthOSHAandEPAre~bOns d LR dcslgned exprmlyto bep.Ne p u o a mutahmtherurbungdischugcd to(heum0aphue However, volatile organic compounds in the form of vrpws may not be so xpyued ud attention nuy need to be lpYentocouvlgmfonnuLnon o r o p b d dcktlorr . I"sepuuar" egurpwnt Rh+r boMtu pmvlde a mechanical me- of Bltering ?he air by w i n g It through a form of filter media. "is6lter also serves u a means of rlistributing the dr 6ov mdy through the spray booth. Obviously. &Y the 5 k moves the solids. it will gradually build up a mpicrion to the flow of air, requiring change of the 5ltcr medir An air prrssllrr dillercntial gauge (manometer) should be insulled on the side ofthe b ~ x i t h with the pilot tube placed on the intake ride and t h e other tube on the exhwn side of the filter brnk to ind i u t e a pressure W e r e n t i d (drop) ac~os..the filtcr bank. When new filter bank has been installed. a reading should be taken and noted. Thv filters will require replacement when a 25 inch increasc is indicated on the manometer. In some state* require. -dlcu(tthatapaam dml" milchk bc ~to~o!rtheBlrtothe~gulmkdng~ lhe spray booth e whenthe airnlatqr Qsr below L cemh point. The p m b #eneralIy ~ n a i d e r e dand m d in incha of rue in a cohunn drua. 1. hhll 8-W m: PIlnt urestor ffltera ue m u h of a drr-rrurd.nt bu(rdpaper and formed into a "honeycomb" am llgurulon. The Sltering action b accomplished by the w i d "back and fh" m m t Mchc air M It passes through the fflter me& cLntri(ug.l fom thmwathe soU& .g.insrthe rmted paper what It nicks.When #prayingin one epot the exhuut air m c m the paint pprriclw 0wunUJ most of the M a uenbccomea flllcd.As the lllmlods up vtithpdnt part~cleaand the air m m e n t Uuough the lptg boothdiminishesud.O"ineh(bQtDtJJ)Ne in L column of run is i n d i d , the ffl(asthen are .tuched u the cormytlonr. E.ch.rhttt hm mrrOfFeffbnticn8" I rrl.rtvc to the ocher, both rclaE.uy and hoiizonuUy,muhng.in . w i d Ing prsslec Y) thu the dr s " miles four attfaces before it leaves the IllMr. In doing so, the iticky un-dryed paint strikes the aurface m d mlheres, only the rir cleaned of moat solid p a n t puticles b dischygcdThk ffltermedi. rquiresm placrment llso when one tuM inch rbt in water column is lndlutcd Thb type fflm however Lns .bout thrre tlma M the @lit Umuntype. Cut6on should be g h n when U& type Btln medi. b uscd In.RLIof C O l L N n t hlghhumwty (90%cz higher) or when water b u c d paints u e w d be cuge of the poadbUty of ffltcr media- "IaCanmL There ue two paper nitem placed In each fflwr frame in back of the apmy booth. The number of h e s in any s p n y booth will be detcrmlned by mze ofthe Illterbank Inbock of the spny bXh'Ihr two most common aizes of fflter media awlable a: 1120120 or 1 x 2 0 ~ 2 6md held in p L n by a PrrU f l w d aira pidMdihon8l .iraue.nllrbk "ea UponWkcarmudtheUkImedi.,hrmrdtrry dlta, that which apr mce orthepimla r"cd and duposcd Of 8pscscrikd nUnna.lhe ymnd fflter LI also removed but not disposed of. A n e r fflter 18then placed in the lutnihme and the old Becord flltoisnorpLced 0wthen.m Ma.udng ~ p r o c e d " w m t r e s l u t e r ~ ~ ~ A double lmyer of one inch tbick p.&k und. Ody one Lyrr occd k r r p l c t d at a time as bulk of paint putides m CN@t bl the in& of IUter thiclme5 4. *dV~ntrgaof 8 flhr trp r p n y booth: a. No w u a rquirtdforranonlof printprreicles. b. Nocompoum%ngofwuerbrrqumd c. l y h t weight in mcrprmmion when floor loodu\g b a problm. d Simple erection and hurnllrrion-thus lowenng 2. Alldm80 flhor: Andreae fllter b a collapsible or .ccordion paper consuring of two ahceu of heavy firrrrwdant paper with earugslionsof unequal sue whjch QaL 136 u-.a PJnt p u t k l a La tbr air ue Durbrd out The ne^^ a m n t l r " u "ta of mrhg rater, FACTOR PAINT ARRESTOR ANDREAE DlSPO H i OveralI mtntion 2 Matcr*L It CUI h d h . Lortnitirlmsb 1 mlcetodr movement. Highhat replacement ne. Time quired for Utter mpiurment type h, r h e a the Jr ayhg the paint putida mrtc a audden change h diredon of now. Centri. hgd fom (rolute d o n ) flings the solid p.rtida off the nuWn into 1 collecting p u ~Depending on booth deign the dr rill tnvel through a number of ruh chuaba The upper antrifugd ruh cham& k the polnt where most of the pigment Is u p m t e d h m the exhausted air md nwhd down the front mtez cumin Into thc mllscting PM. In the lower rtrb e)Umbcr the b u s t rir must p u r h u g UI. 3 2 1 3 2 1 3 2 3 1 3 2 1 3 2 1 2 3 1 1 2 8 s 1 2 other unbroken rater curhh. Agdn. scrubbing the rir and the rioient change in the dimtion of the air moves the renuiniq pdnt pigment before the dr prrvr into the exbaust chamber. Through these two actions the .Ir being exhausted is now viztudly free o l d om pigment cart of Nter repiace. ment in relation to production. haeodor Utter repiaccmenr Lorest i n l u md of s p n y booth Wition Lowest rhipping Md storw cor; of Utter medk mrt per q u u e foot of Utter medii s 2 The rater k h a t e d (compounded). Thir muses the PJnt putides to coquhte and 0-t on the surface. la thc Wud pump type booths, the p u t i d a ue 1 rLimwd off the top I "umt to time. In the n e booth& the water k compounded so that the putides sink to the bottom of the booth. Pmpnly engineered water wash spny booths i r e the most amptable means of m o v d of punt pigments C"the exhausted air tegudlcss ofthe type of paint, lk rirO*ty, drying qned or production n k Solvent vapors or fumes will not be m o v e d in any water .I& spny booth. Horncr, water wash spny booths are the mort amptable types of spray booths to di Mth, nre. and building coda. Standud typ water wash spny booths break down into six different styla. "he design configuntions, air nor. water flow. dvanuges and limitations are listed ,pump 5. Umiutionr of filar spray booths: L Regululy scheduled Ulter replacement k Rq u i d to keep the spray booth operating 'at top efficiency. b. Air movement diminishes Y the Nten b e " e med with p l i n t e Produetion time may be interrupted to change Nten d. "be continuous cost of Nter replacement e. Proper dirposd of Ntn medii is rquirrd. I. Stonge space tequired to keep i sufficient supply of Nten on hand at dI times. I.h u r e of the pombility of fire extn c m must be &ken when different types of mterirlr i r e being sprayed at one time in the same booth. mow: WATER wAsn TYPE SPRAY BOOTHS: The brric principle of opention for rrrndud type water wrrh spray booths is a water " i n nuinuined by a pump providing continuous circulation of vim. A water cumin is maintained by a pump providq a 40 psihead presu~rrand a 10 to 12 psi pressure at the nozzles dong a mdnfold which spnys against 8 de. nector plate producing the rater curuin. There are two methods of wrrhing the paint pigment out of the exhausted air st". Fm by drawing the ur Ulrough 1. Style "A" Is a low misrrnce booth with a wmtile 137 .. nylamiq d n i p . It rltl-mwt down draft booth rppliationr, high production nus, wious Itqb and width making it able to n t l n r m r l l u r p m d limited rp.rr. It h eonddmd a rrrndud type booth. Air entm at the bottom and receives only two w e h c r This design is used In down d n f t water wash booths mort often because of itr limit ed depth. It is dlo urd u the Ntntion back on rpny booth U u t house automatic spindle ma. chines. Water now is 32 gallons per foot of bootfi with a 60 gallon return m d a w l f o l d head pressure of 8 to 12 psi. The eliminator section w be designed to be 18"-24"-30"-36"-42" wlde depending on design with UI dr now through the eliminator of 450 to 600 frct per minute per foot of bootb. Note: If 42" eliminator plates are U n d . awes doon for removal of plater must be in fmnt m d mu. CTYLl 3. Style "C" has vuiable or n a i b l e engineering design features and w be changed to meet the cyc tomen puticulu needs Low or high veiocity air movement is ivdlable. thmugh booth area. The alr receives four w8shn u It prpes through the spray booth water curLlinr It k the most efficient stand. ud type water wash apny booth designed because It .Lo lncorpontes a bamlllcbacked curuin and is modemte in Cost. It has a ram now of 24 gallons per foot of booth with a 60 gallon return. The eliminator action is vuiable to meet design needc The J r velocity through the eliminator is from 500 CFM to 2,000 CFM per footof eliminator. 2 Style "B" is the best type of water wash rpny ' 4. Style "E" opentes on the m e principle as the style 'T".This rpny booth is the Urndud caralog. cd r p n y booth with a rued design and single back curtain. Thii rpny booth is compo& of standud dze panels therefore it does not require any cw tom enginking. It futures an upper md lower wash chrmber. large capacity collecting pan. dotted water Intake p i p to insure sediment free water. circulating water system which forms a con. rturtiy nurhed circuit. removable manifold for ease of mrintenance. hlnged water curtain to allow easy access to the rear of the collecting PM, rreerced d n i n which inrum complete removal oC water from the pan, MZT door lwted just below the fan for easy mrintenmce. The air meives four w u h a , has a water now 01 24 gallom per foot of booth with i 60 gallon return. an adjustable air velocity of 1050 CFM to 1250 CCM per foot of width of the wash chamber. This unit is the most economical unit to purchase and openle LS far LS efficiency is concerned. booth available. It has a combination of the featum that ue found on Styla "A" and "C" m d this combination of double manifolds g i n s it the best nltention. It is mommended to use this type booth when spraying zinc chromate or white synthetic materials because of the difficulty in IC. moving these particles This type r p n y booth is most often supplied to the F e d d Goremmcnt to meet their requirements; however, the cost is very high. I t has a water now of 24 gallons on the front curtain and 16 gallons on the back curuin p r foot of booth with a 60 glllon return. The water mifold height is avuiable from six foot to nine foot depending on the air movement required.The diminator vctions can be designed from 18" and in. mad in six inch increments up to 42" openings An air mo\ement of 600 CFM to 2100 CFM per foot of booth can be obtained from design changes 138 0. CONFIGURATIONS AVAILABLE IN WATER WASH SPRAY BOOTHS STANDARD TYPE: 1. Brncb typc or with atended rater p u . 2 Floor type with cross air m o m " 3. Semi down dnlt. (Air entm h m top or booth and k a v a out one of the sides,) 4. Down dnlt (air enwn from top of booth and leaves through gratings in the noor). 6. Combination down d n l t r m s r draft. E. NO-PUMP SPRAY Booin: The nepump booth is a high resistanet booth. The principles of operation k u follows: A high sutic p ~ r fan. e which is located in the spray booth a. b u s t duct, pulis the air under an entninmrnt plate at 1 very bigh velocity. As the high velocity air current is pullrd under the plate. the air movement forces the water ~?fi.n into a smun wbich also nows under n in velocity unthe plate. This water ~ e u increaccr til it is actullly lifted into a routin; -de or water fdlust behind the entninment plate. Tbe air current must pass through this cylindriellly shaped turblant water column. A t that time the solid punt particles in the air Ureun become trapped within the r a t e r column by the etntrifugll force which is created by the rotating column of air and water. Washing hkes p l a n u the air escapes through the water. leaving the palnt particles in solution behind. The ricing alx water column strikes the eliminator platcr within the spray booth exhaust unit which causes this high velocity mixture to rapidly change dimtlon v v e n l tim- As a ml~, the moisture pmcipltawsaut Md falls back into the tank. Clean air is (hen cxb.usaed through the fan to the atmosphere. The water in this booth k compounded so that the punt particla sink to the bottom. Tbr print solids come coated with an anticouglant wbkb bas been addcd to the r a t e r . and together with the water ue prcripiuted into the w k Drain openings in the nu of the spray booth allow the paint md water mixture to m u m to the front of the tank tbroufi a trough. Heavier paint solids nettle to the bottom xbUe lighter particles recirculate until they am broken down md the pigment released. If Iarper amouou of moimtre accumulate on the top bafneq this indicates too much foaming and r q u v r S the addition of a heavy weight oil to be added to the water. The critical factor determining the proper operation of a no-pump spray booth is the air velocity. Air velocity is mnwulled by the water level. As the water level lowers in the tank. the distance between the water surface and entrainment plate i n e r e a s mult. ing in a change In the air velocity withing the spray. booth. This velocity change or pressure differentkl is ne& by a p m k which aclivates an automatic water level control valve which maintains the proper level of water in (he tank and proper air velocity to operate the spny booth efficiently. When selecting a no-pump spray booth one must have a d q u i t e air make.up available. I f a vacuum mun in the building. the water level control valve will not Yn= the water level mmctiy. If the fan k to be mounted on the roof. the toul sutic resistance must be mounted for; h m the plenum chamber (or adaptor ring) into the suck. plus the normai IOU through the length of the ruck being urd. bCCESS OOOR oisiniomm PIATE ENTRAINMENT CUTE ENTrUlWEhl ?LATE CROflLE F. ENVIROTECT: The Binks EnviroTeet k a new concept in water-wash spray booths. The principle employs a non-turbulent washing action that thoroughly wets the contaminating particulates which can then be effectively separated bum the air prior Inexhausting Inthe atmosphere. In e o n M with conventionalair scrubbing methods, the hviroTect Spray Booth fakes the air from the w k i n g area and moves it through a restricted flm pasrage to form a column of ai? moving smoothly in a straight line. i t b aceelenring velocity. nrm-turbulent p t b of am. W thc air h moved t h g b one or more continuous solid &of wuhing liquid wbere the emtaminant particles in tbe air ue i n t k w l y conll*cd and thoroughly wetted by the liquid. Tbe resultant intimately mingied column of air and liquid is then d*ehnged into an eliminaulr chamber ofmueh m t e r volume. Thii reduces the air velocity and kts the weUed contaminates drop out of the.irBtrrue Well over 99% ofp.rriculate matter can be removed from rpny booth exhaust air with EnvimTect. - A 139 " O.CONSIDERATION IN SELECTING A WATER WASH SPRAY BOOTH: 1. ?be effkiency of the spny booth CUI be determined or improved by a combination of the following conditions: L In miation to the design the wlcl the mount of rater ( O M )per foot of climlnltor retion b c i q circulated the greater the pvtide elimin. 6. The booths should have a water circulating system with no deadends to t n p sediment. The Wltcr flow rate sbould be easily adjustable to suit the ram circulation requirements, ation b. The interior design of the eliminator section iaCIC.YI the eftickncy of putiile movd. M u i mum plgmenl moral is ndlzd when a l y e r rdume of ak L plrvd t)uougb a nndl m a UId a violent c h g r in rir dimtion wtac place through a curl.fn of rater. c. Mechanical r p u a t i o n being uaed ruad or adjustable. b.Ma or dcflnton may be added in the eliminator section to help in puticd 1 I 6. The maintenance Rquirement of the booth should be eonridered such u: a. Removable nunifold to simplify the occuiond d a n l n g and inrpctlon of the upper w d ehmber. b. Easy aemr should be available to the back of the collecting ~ U for I ene of skimming the entire p a and rrvicing the pump suction pipe. c. The podtion of the d n i n sbould be messed to inrum complete nmovd of the water fmm the 2 The higher the m i s t ~ c eto the movement of iu through the b w t h the better the Ntention. L Dcpnding on design. a "hi mistance" booth will pmvide better Ntention md are more comp8ct in design. However Uwy lure a hlgher o p n t i n g COSIand require more sophisticated contrul system for eMcient opmtioa b. Low rcsistmce bwlhs rill not provMe u p o d Ntention as high mustance boothr Howmr thcy m lower in initid cort. lower In oprnting expense and le% complicated to conmi. collecting pan .CECO d w r sbould be pmvided below the fan to dlow erry inspection, repair'or replacement of p u p 7. The typ of compound required should be considmd. This is determined by the style booth, type of m r W spnyed and the materid suppiicr or compound nukers rrcommendationr 8. Om should therefore consider the above listed features and find an efficient booth to meet his mnlr. loul codes. requirements and budget. d. An 3. The mlleeling pan should be at ierct three times the capacity of the pump to minimize the time the water h s to circulate. The front water curtain should extend below the water surface. A weir plrte should be provided to keep mort of the wrchedout pamcles from reaching the back of tbe p m where the suction inWre pipe is located. The weir plate dso facilitates the skimmingoff of the spent panicles bv keeping them up front. KADVANTAGES BOOTH: OF A WATER WASH SPRAY 1. Ampted by mort loal codes rc the best type rpny booth available. 2. Most type of mamiJr CUI be rpnyed into water wash spny b o o b 3. Any production nte can be met. 4. CHE No Nter rephcement. Nter cost, or wasted space for filter storage. I. LIMITATIONS: 1. "hk water must be compounded in such way or rink depending on the type booth or materid being 4. The suction pipe should be louted behind the weir plate off the bottom of the pan to uwrr a Udi. 8 that the spent paint panicles will either float ment free supply of water. Optfond suction u n be pmvided when requid. The water Urd. .U.MN 140 2merundvd(ypwuaNh~booth.rqubc a " n t . 5 " n ' of-. 3. ~ ~ ~ t b c a ~ h ~ dthcwua. 4.Htghertnitwcoa 6. Matenab thu m o t be made to float should not bt w e d In I u n d a r d water-wuh spray booths. Hucrials which mate excessin foamIng or will notaettletothe bot" cannot be sprayed in a n e punp booth. 6. The posslblltty of water pollution should be cob sidered. t J. DownUndw and Downunder SpriCun Booths: The Binks Downunder Booth is a downdraft spray booth used to paint dl types of motor vehicles. It is avabble in two modeIs-Solid Back md DrhTluu. The downdnft prindpk utilized by the DomUnder is one in which ambient or heated air ia inuoduced and forced through dltns u the top of the booth. The air f l a ova the top of the vehicle, around the si&, and beneath the floor is pulled downwar& thmugh Fate. This downward air now helps to minimize rejects by puhins onrspray to the n m insttad of dong the =hide being sprayed. (In c o n m t , the air D m in a conventional booth goes hum OM end of the booth to the otha.) The DoanUnder SpriCure Booth (anilrble in both -7h rith bl-fdd d m ud Solid modcb) ~mbinesthe~donndrnhprintipk~ihceom ~~nrringmc~ofinbwedhatas.Thein68. red heaters help save money because heat ia only generatid when the rays strike a solid M a c e . The S p r i C m principle a n llsd be used in conventional CmrSdrnhrpnybOOthS. ti. TYPES OF SPRAY BOOTHS: There are many types ofspray for just .bout my type of spray applicatjon @le. All these dinerent types M deypHd to meet the pprriculprmdsof the product The ffltntion needs of the spray booth can be designed into any type of spray booth " i . The ryp of f f l d o n e of the exhwn will be delmnLKd by the local codes pertaining (0 the operation of a spray booth in your area Note: for those who arc concemed about air pollution a booth with better f f l m i o n can dways be selected. 1. &nch tvps ff tou& up Ipny booths: L A BMU spnying area elevated rbwe the floor so mu the spray operuadocs not have to noop. b. Pam which ue tobe sprayed arc dthn arried bto the spray booth manually or on a conveyor. c. Bench booths are available with 'my of the fol- ' lowing means of fluation or disuibution of the air m m e n t throughthe booth. (1) B a f L l e P h (2) Distribution Plales. (3) Perforated baffles (for vimous enamels, ktcr mdJdhdw5). i -- (4) R t n t u T u t o r ~ (6) o (s) rn"&upLLarithMen. t 0 hV m oel a p t~u c r m r p M a r . (6) Meul ckuubk (expanded m a d ) . (0) Metal deurpbk for gtindmg operations. (10) Flockrmnvithdimibutingplatcs. 2 Roar type ot walk4n: L Can be used lor spraying small pana on a turn table a largehard to mow 1" b. Items to be sprayed may be carried in by the opaatnraonaconwyar. e The rlr movement k dways directed over the spray operator from behind carrying away a11 contsmurates. d Floor type spray booths can have the same m e w of air distribution and Blarion as bench type booth6 (IisIed above). The diredon of the .ir m O n " t thmugh the spray booth can be: (1) -cmy- (2) Sard down 6Rh. OJMC paint parricla may bepllledtmrardtheopemor.) (3) (4) UPS. Specla1 p ~ r p sprey o ~ booths: L Drytypeforcvpmicmntcriplr. b. V-I type for solvent apnying md cleaning of purr. e spnyboothaforspnyine~thaIeormde femw meuL,ue uaulty c"j of ahminu"MinlarnrrL d DoMldnftwaIerdspraybooth6designcdto Wa Inair h m theceiling ud then be r e m d through -in the floor.This type of insullation is the cleanest rype ud it is widely rued in theM0"indUwy. e. B a d rowingspray booth. t nllckrprybwth. & Automoth apray booth for the refinishing of - rutomobiles. (1) (a) DanUndcr (b) Dovnu&sprlcure 0) Dry(a) RP. Paint Amstor @) h Exhaust chambers. brfne or filter type where a &e pmof mom is available for spraying. Exhaust chambers can convert the room into a spray area. These chambers are the back section of StMdard type s p n y booths. L Flock type lor spraying powdered materials utiMng a wire s a n n md dimibuoon platrs. j. Grinding booths which contains expanded meul C k a n a b k aterr. L Down draft dry bench booths for vitreous enamels or @hadingoperations. 1 Canopy booths using brfnes or filters. (Works similar to a steam (able.) m. Upcinh "4booth for paint or s t e m cleming n Special Chysler and Ford d a ~ g n s . .. IL CONSIDERATIONS WHEN SELECTING A SPRAY BooTn: ?he selection of the proper npiay booth rqubu conddp.bit thoughr Ihe inttipl in-nt in aspmy booth a n bc returned mmy times over if the correct one hM been vlectcd for your needs. Some of the most Important considerndons ue: A. SPACE AVAILABLE FOR THE SPRAY BOOTH AND TTS LOCATION: 1. Consideration should k &en M to w h m the spny booth should be located and that the .IC.provided M uyommodDte the compkte spny booth S @ mention should be ghm to thc overhead we-, ak ducts, piping, srmchvnl members, where, how far, and in what direction the crhnun stack muat go to take the exhaust air from the spny booth. Making certain that all access doors can be open is motha essential foccor. The ovenll outside dimensions of most dry type spray booths c m be calculated by lddmg two inches to e.ch side lnd two inches to the back if only the inside dimensions are given These two inches are normally required for the outside hnge. A minimum dear space in front of the booth equal to twice the height of the front end of the booth must be provided for. "his will &e the best poYible operation of the -my booth 2. The mount of air m"cnt h o & the booth,the olpc of tlltntion needed. type of booth " I . 3. The now ofproducta to and from the spray u e a should be M direct rspoadbk. One m r t d ". nla the m m e n t of the product dlrrab, through the w w booth, w o r h g depth w a l k 4. It i s ~ u g e o u s t have o a we dnin available in the spray booth f b r . 'Ihb pennit thc d m of the spray m a , prevent dirt contm!nuh I42 of the product, ud i.clutrce elem up. -ever. one should check rith I d codes tom U t h b is pcnnldbk. 6. It Is desireable to build the spray booth on a cement curb. This will "isc the accumulation of water under the booth h g e and will .Lso prvide a level surface for the erection of the spray booth in addition to extending itc uvful life. This Ir especially important for those who wish to wash down the noor of the booth frrquently. 6. The electrical power md water requirements for the rpny booth opention such u; locrtiun, rvdlability of the proper voltage, current. cycles, phrv and type of d&ncal quipmcnt thrt is go. lng to be required for the spny booth installation. 7. The altitude must be considered in the selection of of the exbust fan lad motor beuuse fans must operate at higher R.PM.'r and in moct UYI Ilu tudc in exof 3.600 feet above r r level they Jlo require special motors B. THE SIZE OF THE SPRAY BOOTH: 1. Thr si20 of the spmy booth is drnrmind by: a. The drc of the lugest object to be rpnyed in. dud14 UIY necawy product handling quip wnt. b The number of purr to be in the spray booth at one tiw and the number to be lprrycd at the amr tirm c A mini" of two t a t of 8pprr Bovld be Uuorrd on each ddr of tbe product to pmvide " i n e a t betreen the object and the l p n y booth w.IL Note: 4Vhen u d q rlectmstatk @my quipmnt be sum tbe rpmy gxn h no , dopr thrn 30 ineba from the mew wdb of &@rqtt-J(h. .. d 81. to dght foet mlnhum f o r d *ray opes & plus I .a u 0 w . M for f ~ o the w wort, ~ Li MI icontlnuoui conveyor. If artonutic y a y q u i p m m t k urd,am adquite rpmfor the MehiDc mdI4 to the number of spny lun being urd m d the ship of the p a Automrtie r p n y guns lbould a m be dour Uun 2' 6" horn the dde of the booth on rlm kpeed cob wyom lad 3'6" on hlgh speed conveyom a %&lent spray station should be provided to v h i n e the r q u i n d Nm bulld-up. L Spraylng should not begin dowr than 2' 6" I"the conveyor ope*. I!thir is iproblem, mxtlbula CM be added. 2. Thr heiphf is d e t e r m i d by: L The highat point of the obwt wbieb k to be 9rayrd plus imlnimum of two feet cleuance. b. Conveyor ehua rhould be considered and not extend into the spray mi only the products .nd their work holden Sanituy hook(%)should he provldcd on conveyor trolleys Y) that dirt tUlI'dS CM be provlded. L PhtfoOmrr sbould be mnddered and pmvided If the spray operator must reach above the pmduct. 3. Chpth should b.: L Deep enough for the work to be endosed by the rpny booth and i minimum deanrice of two feet from the exhaust vetion in back of the spray booth. b. The spray opentor should be able to dlad within the Loat line of the rpny booth. (Exapt & bench boo*) . 4. Method of ippllutlon: There are four basic methods of spray application used and each will require its own apecial considention. L ilLatomisatronwUlproducethegrrucamcunt of over-spray and rebound; therefore, this method will repulre the greatest veloctty throughout the s p n y booth. b. Airless atomization wlll produce less " p r a y and rebound, therefore, lower air vclocitia may k rued. c. When elecrronvtic amamion, whether air or rirltJs atomization, is king wed, lower air vek~~i6es should he considered. d. True eiecuostatic atomization will produce the least amount of over-spray and too high an air velocity will pull the paint particles past thc product C. AIR VELOCITY: 1. Tbt air velocity must he high enough to uny dl solvent vrporr and ovempray ewiy from the punt. lug LICL b w air velocities M muse dangerous conditions md increase m l i n k m c e cost 2. The average velocity for most materids and ippli. cation methods b 125 F I M . (feet per minute) Note: 175 to 200 F.PM. can be obUined whenthe ippliution involm -ic materi.ls or automatic reciprocating michinec 3. Electrostatic spraying q u i r e s " w h i t lower air velocities depending on whether air or drlcrs alee trosutic attraction is kinr u r d or true electro static atomization. (minimum 60 F.P.M.). 4. Thc roluw of a& .ad nlodty for ispray booth exhaust system an be alcuhted by wing the following formub Width I Height (plus the .m of one conveyor openirq) I V d d t y desiml will qual C.FM. of air q u i d throurh the 9 n y booth. Depth 01 the 9 n y b o t h I( not figured & the aleuhtion, Other mndderations ye: L V e l d t i n thmugh booth genenlly nage from 100 FJX to 200 FSM.and vary with the type ofoperation taking p h a wlthidthe booth, for e x l m p k (1) Flock 9 n y booths (75 FPM.) (2) True eleetmrLtic rpnylng (90 FSM.) (8) ~ e c t m N t i c a t t n c t I o (6&100 n F.P.M) (4) Auto and huck b o o t h limited pro. (5) (6) duetion (100FSM.) Hand spray (125 to 150 FPM.) Auto spray booth for production with a& ito&IW 9nY PIIS (125 160 - FSM) ('I)Auto 9ny booths for production wlth dectrosntic (60100 F.P.M.) (8) V u d (150 F P M ) (9) Vitreous enamels (165 to 175 FSM.) (10) Oxinding booth (150 FSM.) (11) D o m d d t bench brush booth (200 to 250 FPM.) (12) Canopy booth minimum of 100 F.PM. mer rotk yu with 400 to 600 FPM. uouad petimeta of unopy, b. In Ntnbwtbs becaw of the limited air v e l d ly thnn~ghthe Nta the filter y e a may have b be to Minbhl dqUl&lk T d o C ity through booth. c I b e erl&ted rLm must rko Indude l a p s accrued ia the system due to static pmrurr as the air nom through the ehrust stack and elbow. I b e computations nude must then he compared to istandud erbiust fan table. (See . pages 12 & IS). m u s t ka an be sized by BintC Mfg. CO. if cusk" provides brdc daw: Hemt of mot, locstion of booth, length of stack. number of elborr, m d beight of stack above mof. D.THE EXHAUST FAN: Tbc exbust fan k the heut of any -my booth. A fan rheei icb very much ULe ishovel. Every time it molvar It dA-6 the w e quantity of air. In i system the fan will d d y e the m e volume of air motution rrgardles of the fu~speed and l i r dendty. Note: disregarding mall effecu of mm. pmsion i t bigh pressure. The M ~ U Rof a fur b N& that &cy will operrte i t the m e efficiency i t dl pointr in ibystem regardless of where It is p i a d . 41 /- n e prfoomrmc~of a fM i~ hud on three bulc h m . n e f~ mufactumr can provide fm perfoman* tabla md CUIVCI rhlch graphidly shows dI porible combinrtlorrs of C.F.M. and static p i ” C possible for MY given system. There M howwer, a peat m y other considerations which enter into an lndlul. dud fan aeleetion for a system. Themfom before one b able to engjnm a system he sbould dwayr check with tha fan manufacturer to find out what type of exhaust fm should be used. Its size. lad efficiency mquimd for your puticulu application. M a y manufactums rill engineer the system for you U you p m ride than wlth tht n M g p l y information required to nuke their ulculationz The w h kvel in mort Industrial applicitlons by present methods ofmeasumment ue generdiy accept. able up to 85 declbels depending on condition+ Un. fortunately at p m n t there M not set standuds for rating the noise level of fans In such a ray that it will have m y red vdue. Fan no* may be ittxibuted to m w freton The mod Important ue tbe volume of dr, upicity. borwpown. unbient condltlons, genenl constmetion of the fan and the p-a the . i ,mwt follor. However them b a mrconabk ~cumte me.sJrine system av.Uable. It h u been found that In the medium homepower nnge the no& I d b In direct pmpoction to the fan tip speed. n e tip rpecd table below and the previous fm tnbh 011 be wfuI io approximating the noise kvel ratinp This t.M.h O d Y intended to be used u aguidc Md&rrm ab aolutl rdue. Cam” senr md nrprkncr at p m n t ~ J Mml futon to condder io the dalgn r b m nok heir m y be IWCIJ. dp choH If nobe Iml b a problem then one should d e e t a larger d u s t f~ U pcmihle. A exhaust faW U pennlt lowering ofthe fms R.P.M. and thhb WUlower the no& level and s a l provlde ruffieient air move. ment The customer should provide deciblt miding required then Binkr VU drc the fan accordingly. Blowers CM be fumirhed If proper noise level cannot be obtained by the use of the standud v m e u k l fa E. STATIC PRESSURE Air moving thmugh a duct system under the action of a fan haa tm pressure eomponentJ, atatic pressure and velocity pressure. Static p m s u r e am in dl directions and is of uniform magnitude in any given chamber of the duct system. Velocity praaure nets in the direction of the flow and can be detected by its effect on a streamer placed in the duct Chamber. Total prearun is the swn of static press- and velocity pressure. Because n o i n 4 opentingpressures in spny booth duct systems are low, theu e t u d e is mensured by the vertical distance they cause water to rise. hence the tenn “inches ofwater column pressure”. An instrument for indicating such p r e s s m is the manometer. VACUUM Fig. 1. In its simplest form th. manometer is a U-tub. about hall filled with liquid. wnk bath rnds Of th. tube open. th liquid n nthe same height in uch Ion. !=IO. 2. When poritiv’. pressure is applied to one 100. th. liquid is forced down in that leg and up in the other. The dillerence in b i g h t . ”h,” which is the sum 01 the readings 88nd below Zero, indic8tes nm Pr.uun. Fig. 3. When 8 vacuum is a p Plied to one tag. the liquid rises in that leg and falls in the other. The difference in height, ”h.” which is the rum 01 t h readings a h and below zero. indicate. lhe amount of vacuum. c a u e f y of Ihvyer Instruments. Inc. t Tam TIP Jpwd Otclbth fftd PI minute) (approximate) The manometer can be used to indicate the condition of filters in the exhaust system of a paint spray booth. When the exhaust fan is not operating, static air pressure is the same throughout the sj%m. The man- m-m 60-65 65- 72 72-79 1 m 1 1 4 M w I 79-85 1 m 1 6 M X 1 85-91 rm-1m 91- 97 1 m 2 0 0 0 0 97-la3 8Mx)-looOO lwoo-120M) ometer indicates this condition by displaying “zero” height of water column. PI in Fig. 4. 144 F. METHOD OF HANDUNQ THE PRODUCE Conddmtlon should be chrn as to how the product (I) uc to be h.ndled. If tbc pmductr LR to k p l n d on a conveyor, will It be m overhud type, platfom type, chjn on edge, ete. Will the product have to enter thmugh the wdlr of the spny booth. if SO, how luge does the conveyor opening have to be. 0. STANDARD SPRAY BOOTH va CUSTOM BOOTHS: Not dl spny booths mud be curtom built Mmy UF rtrndud aWoged items Strndud abloged rpny booths will c a t I= and can do the job q u a y P well, in m a t Instances shipping md delivery dates will be better on standard items, as r e U m cost I c g Fig. 4. ZUO inches of water column With the exhaust fan operating, 96 in Fig. 5, a negative sIatic pressure is dweloped in the space between fan and ffltersbecause of the resistann the ffltersimpose on the free flow of air through the exhaust duct. This negative static pressure is indicated by the rise in height of water level in one leg of the manometer and the corresponding drop in the other leg. The distance 'D" between water lwek is called the "water mlumn height" and usually is expressed in inches. H. LOCAL CODES: 1. Lwl code requirements or laws ha* been initir. M by p n c t i d y cities, rmta md inrumcompanies reguding spny booths type of rim. tion mquirrd m d insbllation. Check with your loal ruthoritii for these r q u h m e n t c before ordering m y spray booth for their requirements. 2 AL pollution ir being taken more into consideration these days, therefore, the exhaust discharged must be considered more imporhnt than befon. 3. N o h pollution an violate the rights of other per. sons and the courts will protect thsc rights.There. fore a & e noise In a plant m y mu= adjacent prkrtc propnty OWto Institute legd action for nUef or put I stop to the ex& no&. 4. Tbc National Fke P r u W o a m t i o n Interlutlond hr I d e w mgulrtion booklet which a m a t b e m a t frequent CUI= of I L a I n a r p n y au and fire rrlul.tioar m q u M In most cities and statu You m y send to @e IoUOring a d d m if you rLh to procure thL booklet. N a t i d Fire Pmrcerian A6.a." Ana.: Subrriptions Department B.tte& W C Y ,9" Park Ask for booklet NFPA No. 33 Spny FWi. 1. ELECTRIC WIRING. LIGHTING FIXTURES AND Fig. 5. 9"inches of water column As filters become loaded uith paint spray, their resistance to air flw increases. causing a further dwense in static pressure in the exhaust duct. The manometer displays this condition by a further increase in the dir tanee between water levels in its two legs. A t some predetermined point of manometer "reading', spray booth filters uill be considered "dmy"and should be replaced by clean ones. Clean filten offer the least resistance to air Row. Maximum air Box. in the exhaust duct (indicated by minimum water column height) means maximum air flow through the spray booth, offering greater environmental proteetion to operating personnel and ensuring a higher quality of product finish. Sct Exhaust Fan Tables on pages 12 61 13. SAFETY CONTROLS: Adequate lighting in the spray booth is essential in tunring out quality work. The operator must be able to nee what and how he is spraying or that automatic equipment is functioning properly. The type of lighting, lightin? controls. and electric wiring that one chooses is dependent on local safety codes and personal preference. Some t j p s of lighting a d a b l e for consideration are listed below: 1. For work t h a t is being done deep in the spray booth, top lighting as well ps side lighting should be considered. 2 In small booths where the spray opentors stand at the open end of the booth. angle type lights are SUIdcient. 3. The trpe of lieht fntures which are atailable can be either incandescent or fluorescent and fall into three different groups: ('Is0 2155 2285 1la 1313 14P 1641 1750 189 1914 1969 2023 2078 21M 2297 2406 841 942 ton 1279 1346 le1 - 11%. 11% 18 11% 24 18M 18% 10% 18% 18H 10% 18% 18% 18M 18 24 24 24 24 24 24 24 24 24 24 24 18% 18% 18H 23 23 23 23 34 34 34 34 34 34 42 lo00 1100 1125 1176 1200 42 1300 1350 1376 1400 1400 le* 24 10% 1M . 18 23 23 24 24 24 24 24 24 24 24 24 42 42 42 42 42 42 42 42 42 4a 24 24 23% . 6 8 6 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 :4 I : 4 6 6 ,6 8 8 8 6 ' 1 201165 1 201129 1 201129 1 205147 1 205147 1 205148 1 205146 2 205148 2 205149 2 205149 2 205119 2 205149 2 205149 3 205149 s 205149 3 205149 2 205120 2 205120 205120 xC5121 s 2051s s 2051s s 202 20-5154 2051% 2051% 2 205167 2 20.5157 2 205157 2 2Ml67 2 m157 205157 205157 3200 1020 uoo 3632 6441 6B76 M50 74 m.5 80.3 87 70 254) 3500 72 a13 ?6 7422 W.5 n 9119 9339 79 80 9659 81 0024 10101 1073S 81 82 63 M 11260 llm 113395 15315 18167 19140 21060 lOBs0 21W 22300 4513 6677 M JogD M 71 485 71.5 72.5 78.5 6638 73 n.5 7- 77 78.5 79.5 M.5 6570 79.5 m.5 81.6 81.5 9161 MIDC 8579 0857 9154 Ws4 82.5 63 M 72 78 79 lwQQ 72 75.6 83 17015 1802# 20057 20403 1 m M n m 84 1- 5m 9118 10285 (OW 11m a m n 11726 13892 06 79 63 65 67 88 M 16% 31% 3Uo 80.3 mzs 11868 9456 11182 7 w m.5 71 1 w 13080 '15 70 63 85 16380 17433 1e531 27000 1m00 19300 203#) a 20700 67 l@MO 87 am a4 W ps#) am 91 24m 27250 2429 254w 25950 W 01 91 my) 92 26(% 20-3460 41250 01 Jo8w 92 94 zswo zo W 90 m 81.5 81.5 1w13 PJOO PJSO 23MO 2- 67 08 78.5 82.5 03.5 M.5 1- 2ww 21450 23000 74 74 m.6 80.3 2u00 2w0 67 m 84 85 67 87 68 W 80 91 91 92 M -. of rouM bnl ol Ilm hnon #"A" umb. hkm 10% (rwn(aH.l. bdt mo..PmdmiIyol mom walls .nd 1YI. LwLd mnWW 6MI ramd bnl. hrtJ*d.ourdln" m y b. nqund%% DBA .Dnr a w Hu%-1 .nd&lks Englnnling a* bMlumn. 8on 1 7 9 RPM mc(a qmd. D"k Dlh. with the above to &ut off the .Irto the q r a y gun when the exhaust Ntcr unit becoms dMy and the m o u n t of ur being moved is su!fidently d u d . 7. A water sprinlrler. u r b o n dioxide or dum system may be r e q u i d to tum whenever the tempntw in the spny booth a m rises above a d n point k a u v of a fue being p m n t . J. AIR MAE-UP OR REPLACEMENT: An air make-up or mpiafcment syNm is important because of the l y e roiume of air exluurtcd from rp-j boo?hs This ahaurt L d n c k n t to p r q d ~ f c two or more complete d u n g s nny hour. Under such conditions in winter, the (PRY m a may become cold and uncomfortable, nnLh problems an uicc be cause of spraying with cold n u W s on cold pro. ducts in cold air. An air make up system will provide I wall as to even tpmpentum md c l a n Nteml u r . a r e proper booth pnionnu~ce. 1. The air which Is m p i m d k heated and Nted be. fore It enters the spny booth .RL 2 T h systems should be designed to provide a r r p l u r w n t of air Kcording to the volume which 146 %z2 ..u k, in ( h . 113 12 1/4 112 3/4 18 18 18 112 24 24 24 24 24 24 24 24 24 3/4 1 1H 2 3 3 3 3 3 24 5 5 5 24 1H 2 34 34 34 34 34 34 42 3 5 7% 7% 7% 5 5 5 5 7% 7% 7% m 0 0 0 24 24 m (*I 0 U N D U m m 74 78.5 00.3 70 72 73.5 n.5 m 00 81 62 62 a 5 8.5 84.5 ms 4815 56851 72n 767Q eE4 8426 9131 9796 1043s n 795 m.5 81.5 K K N 84 85 87 4030 82.5 4545 (13 6867 7971 84 85 85.5 87 uoo MS3 84.5 85. 86 07 260 280 74 ms 83 13901 K.5 84.5 87 15325 1m 4 84 87 88.5 88 m 215#) 86 42 84 1- 84 42 86 162550 m 42 42 42 87 87 l(Ws0 86 1lM30 20100 21350 87 42 42 81 K K 62.5 83.5 845 85.5 87 125 125 125 125 130 130 130 130 130 130 135 135 135 M Lo m psoo 42 42 91 m PlW 42 92 48 91 z37m 32250 m 19 .m e1 01 92 93 260 260 275 275 84 10100 06 m 310 560 84 84.5 8!i w M.5 Lo m 91 91 93 360 560 12950 I4100 lsOs0 1 I O lw00 I 9750 xu50 27254 84 85.5 M M 85 86 89 a75 89 W 80.5 W w 92 92 360 3m 3m 370 370 360 380 400 How to a b exhauat hnr tor rpny bootha. Eumple: l k v type IDRV booth l i l h inside dimraiow 1 5 wick bv 7' hugh. IBooth a p r h 60..not enmr me alsu1ation.l kltiolv 15' a 7'. lhich coma 10 105 q. h. or me Moth hce a m . Multiply the fmm area bv the HIociIy dnirw. ( N m r lm tk.n 100 FPM. @enmllv 125 l o ~ F P M . l F o r r ( l e e M m o k , m r r r n t a n a i r f l ~ r ( l r o u g h f M bwth of 125 FPM. Our 105 Iq. II.I125 FPM4urla 13.125 CFM. Ennr the fan Uble above under the Y" m t i c oreswre column. The nureal CFM ~ r * a t e r1h.n w r ulculation is 13.892 CFM. Thia i s fan Model 304307. Diwdinp 13.892 CFM b y 105 a.11. b o o t h f K t b u been exhausted and dm h a t this . i ,to r designated t e m p n t u r e and humidity. The air mry be heated by one of the following m e w : a. s(runruppiy. b. Hot water supply. c. Indirect oil r i d . d. Dimtgrrfired. . .c. Indirect gas !id. L Elecuic. Note: Direct fired means the products of combustion enter the air supply. LBTU of flame hen1 isqud to I-BTU01 heat in a direct f k d system. Indirect fid is only about 70% u efficient. uul g i n r 132 FPM. Model JWm? utidim our minimvm 125 CPM r**rinmnt. Checking 10 m il a Ian with 1 . p 00.city will w k , w m (tu1 1an Model -305 ka a CFM rating of 11.726 CFM. Diiding mi# by 10s a.h. m gn 112 FPM. Thia is less man the desimd nlociw thmugh tk. booth. Model 501305 wit not be nt*C8y. In Wl.ning a fan for a *om & m a y Moth. m a l other @le. mm, of amIic Iwismncc must be ukm into conridnacm Vow Oinks rwmmmtive will gladly .nw YOU m the ulcu1.iton 01 1h.Q r.u~uncu. 3. I n a c l o d system such as an aslomobile booth air mate up syuem should be d t s i d to providt a dighUy pealei or balanced volume of incoming air than is being exhiusled. Ths will provide a positive pressurr in the spray y e a thus helping l o keep dust and din Imm mlering. Note: If the airmakc. up is too p a t it could possibly cause punt 10 p a s into the room or tuck lord the filten 4. A purge y d e should be incorporated inlo a closed spray y e a if posiblc. This will insure that Ihc air is clean before my spraying opention ern bcpin. I(.QUOTATION REQUESTS: Quotation request forms u1 available for rrqwsting r h e m a spny booth 01 lIr NPPlY P ~ O u t i O Tbae forms LR nriiable by d i l y for Form N u m b 0.256 for s p y boothr ud 0-(NR for air NPPb ryIV. MAINTENANCE ~ h nuintenanc 01 a rpny booth k i m p o m t if OM wmm to receive tbe lull benefits fmm bk inravnent Tbe fouowing list coven tbe mort Important poinu: 1. QcuJiness k important to cut down tbe paulbility of fire I "acajve materid build-up. 2 hoper mrintenurcr will help produce i hi@ qudiiy llnLh by minimizing din eontamloation. 3. Water wash rpny booths require the water to ham compounds added at regular l a m 4 lo that the m n r p n y purida can be removed urd to p m n t nut. The oDmpounds uuy tbe particles to noat to tbe surface in pump type booths md in n e p w p booths the puticla LIC caused to slnk. Oil must be applied also in nopump booths to keep down the foaming action, rrpecklly wben water is found on the upper b d f k Cutu" a u l d check with hlr compound manufactums dm to try and find i cumpound that will not foam LI much. 4. Roper water levcis must be maintained either m m udly or automatidy to keep the rpny bwtb operating at peak eKdency. 5. Filter spny boo& require rmintemce wherever the Nter bank or media becomes co coinrd with 0rrr.rpwed partidm that It rsducrr the lir m o m ment thruugb tbe rpny book DMy flltm B w l d k WWmd mnmad hom the p m n i r r d ~ l l p l~ d Iny anpmor air t&ht cap WDm 6. B.mc booths require the slpplng of tbe hma and abaut stack priodk.ur to pmmt the poribPIty of 7. Srrlpabk or pcl-rrry W n g whkb un be pu. m d sprayed on tbe rpny boo& rp1 belp in Mintaining the ddineai of tbr rpny Md a h provide tbe ene of drkd paint remmal. A helpful hint In working wltb rtripable coat+ k to YIC two inch " k i n g tape on all r a m s befar ap. plying tbe coatin& Thk mctbod p m m u tbe r&ihble coating bom getting Into tbe and dto ddd in pulling tbe coating free when It be. COma IIw.cpuy to dean the booth. Nolr: Do Not UI rtripablc m tmp on the h t e d s u h 01 r p v booths bcclur Ifit pulls free it will plug the water pump intake porh or plug n o t r l a 8. Cbeck cxhruu fan lnd ^V" belt tmdon. L Fan m d motor Bould be able to wm d l y by hand. b. Fan bearinp are eithet fuUy d e d or equipped with a p u c cup, Um.p c u n n y 1Whovn &. - . of opntioa c Fan b h d n hould be checked and lnrpccrcd PcriOdiUUy for arrnivc paint depcxlts wbicb wU decrease effkkncy and may unbr*nce tbe blade musing e x e a i r e ribntion and podbie b n k w Never strike the fan blades for e l e m iru PUTOU. Jwayr use i mipper to,dean ~ tbem. (Curtion: do not UIC I stripper which .trrdu dlnnlnum) CbrrL drcek motors L For the flnt boun of opcntlon d e c k moton OeCaionJly. Trwble wU be indiuted by bi@ openting t e m p m t u r a or nobe h L b. BJI bearing moton qulpped with a grease flt. Ung wlll rqulre pasing ippmrlmately o n e per month If opented continuously. If they have OU wells tbcn tbey should be inspected dally and oUed U required. 10. Cbeck (be medoad heater eiemenk In tbe w e t . k dvtn Heater eiemenk ue drays -ped wltb mpcn rating& T h e lhould mad ippmxi. m t d y 5 n to flftccn percent higher than tbe full rating of tbe motor i t opetating voltage. "his fuu load nting k -ped on tbe motor m e piat. md dto indicated in unperrc Tm high irating of beater elements pies no pmtcaion Too low a nting uurer the ~Lvtll to tbmw out dunng start. inf periods or In hot w d l w r . 11. Always start one motor at a time beginning with @. the fan motor 5rst. 12 Cb& circulating pump unit .rfollmr: L "be pump unit sbould turn nrily by hand. If It d a not. tbe packing @and nuy be too tight. or the motor coupling out of digment. b. A slight drlpplng of 5esb ritm Bould conu f"tba pocking gland wtQe th pump hoper. ath& U l t d a not. th pack@ gland b tm ugbt Md rp1 wt the pump du& alldng the pump rrl to Lo md nuy maod the &ator. V. ACCESSORIES A. Tufoc upparing the product whili k ir k he CMd, th. cvpc of "tlblri available an 11 follon: l. NortMtlngforU@t lordt,d w a n d no l r p 2 Hemyduty np to 500 lsrlolds.Ither b u mount. darltbkp 3. blotor dmcn tumtrblr to turn the pmductr aukmUanY, lpad b djurtrblc. 4. h u m . l * Ult hunbbla tops lor picking up bcrry ltemc a p d t y 1OOO Ibr 6. Tum b b l e tops will vary In .Lc f" 10" to 42" depdlng ctn requimnents B. ORAFT GAUGES For the cllcethc meanmmcnt of Jr prroavc differ. ratid- ihk indiarr. when the rpny b w t b !litem B w l d be m p W C. FILTER DOORS Nter doom rill p m m t dust and dirt bom entenng tbe l p n y uu and yet p m i d e rumcknt air rrphce ment .addWtlbution D. S P R h BOOTH SCRAPERS: S p n y booth unpm .R mmctcd of i aon-femur, Eon rpuklng n u a for tbe r n p i w of tbe walls of Y" booth. 148 LcoNvEToRsyFIEM8. 5ucnceofthirbulktlnonothsmdesnukeItofgreu ~smansuedalgndfa~thcwork rhieh 1,to be painted to uld fnmthe .ary.rrr,cut ~ d a m o n m u a k l ~ a p F. SPRAY GUN RACK AND SHHELF: Tht spray gun rack ud shelf Is mounted h i d e the rpny boothso hLIh.2 opvnun MEtore SPraYw alps uld other ne“y itmrs G. ROATBOXES: Float boxes ue designed to ense and maintainurcume wuer h l in the splay b o o b wnter pan. H. SUCTION SCREEN: nK action eaten is placed on the water wash spiay booth pump Intake and prevrnu any large lumps of paint residue from entering the pump causing possrble damage or plugging n d e s . L INTERLDCKS: ln*rloclrS are additiond safety devices which a n k added Into the spray boothsystem to do the following 1. Air solenoid nrlm to cut off the compressed .h supply into the spny booth 2. Air Werentid switches to sew when a V.MM IS k i n g drawn behind a fflter bank. The ezhoust fan be cut oE and not turn on unffl tht fflW bank hrs been de& 3. ElCClrostatic spray gun Interlock is placed In the system where no power is supplied to the S P n Y gun u na the r p n y booths efan Is in opauloh J. SLUDGEFILTER: Sludgtill~nare -ling acreem whichhave antio 01 50 gallons per minute bluatjon a b m per atpan foot of surface area. At the other end (here is a high p r e m blow-off which b l w the spent paint particles into 8 mnuimr. bnpnuncc. EnvlrmmanUI Protmtlon Agency IEPAI-A federal agency Involved WIUI the poUution ot outside a&.Them ue no EPA mgulafionr thu apply to solid conurninants b u m paint spray booths. There am EPA regulations on solvents. Their guidelines are intended for very heavy concenfntions of poUutanm. State and Munlclpal Government#-There are d e pvrments ud agencies u all lmlr of gmmment rtru ye invohrcd in coda, replations,and appmvnl of paint wray facilities.These Include Industrial commissions. departmenu of health, sanitation and fire depnnmentr. You will and that the great majority of these are lpounded In NFPA 33. The followlng list of spray booth regulations is taken hom NFPA 33.Tnese am the regulations most frequently encountered. 1. Chapter 3, Paragraph &A clear space of not less hn S’LY on all sides of a spqv booth shpll be kept bee ofmmge or combunfble construction. 2 Chapter 3,Paragraph 9-When spray areas are lighted through glvs panels only tired light units shall be used. Panels will isolate light from spray M 3. Chapter 3, Paragraph 10, (h)-vlslble gauges; or be audlble nLrms. orprrosurr .cti~teddevice~rhp~l lnstauedtoirwvethe required air n1Oclty. C Ch.pter 4, P.n(p.ph 72-The space within 3’0‘ in .UdirecUon~d” OPmingothcruM an open hunt rhrll k COnSldacdMCks 1,DivWonZ 5, ch.pta4, Ph72 (a)-= CLU 1, Dhirion 2 u t a e n e n d . from the open face of a booth 5’0‘. If the exhaust fan 16 interlocked with the spray qulpmenl 6. chpta 4, ppR(p.ph 12 @&nK Clprs 1. Division 2 M “ b h o m t h t open face of a booth IO’K If the exhaust fan ls not inlerlocked with the spray VI. REGULATlNG CODES FOR PAINT SPRAY BOOTHS: Vaious mgulPtoy agencies claim RsponrjbiUty for dr terminvlg the safety .nd leof ppint spray f.dlities. 1.e. spray booths,enclosures .nd spray rooms In order to properly advise you and your customers of(hex agencies and their functions we have listnl the primyr ones h m : Underwriters Lab IUU-UL is not a government agency, but an enforcibie code. Testing is for safety b u m an elecfziicnl fire and sm& mdpoint. A spray booth component, i.e. motor o r light fixture, may be UL apprwed. but spray booths uhmselns are not. Factory Mutual IFMI-h hdustrid underwriter using oun ~ r p c o r i e to s test, evaluate Md appron q u i p men1 inslnlled in their member plants (applies equally to FIA. or LRJ.). Occupational Safety and Health Adminiitration IOSHA)-This government agency is concerned with safety inside the plant, ud the rrgululon regarding the use of nYMlable or mmbustlble “ids.Marc of this regulation is based on ANSIINFPA 33 standard (see below). -Mm=nt. 7. Chapter 4, Paragraph 9-Portable electric.Iamps ahall not k used in any sprafig area during sprny OpoPioM. 8. Chapter 6, Paragraph 5-2.1-Ventilation for con. n n t i o d s p n y operafions shall prwide an avenge nloaty of not ka than 100 FPM. Electrostatic operations shall provide M average velocio. of not ley hn60 FPM o n r the open lace or QDSS section of the booth dunng spray opentions. 9. Chapter 5, Paragraph 67-Individual spray booths shall be SePamtely ducted l o the building exterior. 10. Chapter 5, Paragraph ii-The exhaust durc discharge point shall be not less than 6‘0’ from any combwtible exterior wall or roof. 11. Chapter 7, Paragraph I-Spray ares shall be prB t e d with an w p d automatic lue eninguishing system (No1 a Binh responsibility). 12. Chapter 8. Paragraph I-Spraying shall not be con d u d outside of p ” m n e d spraying area. 13. Chapter 8. Paragraph 3-All spray areas shall hc kept Iree from the accumulation of combustible deposits. 14. Chapter 8. Paragraph 9-Spray ANSUNFPA 33-The industr). bible from which most codes on painting operations a r e written. Provides recommendations only and is not enlorcible. The in- booths shall nwt be alternately used lor different types ofcaring ma. 149 cakh,rhactheircombinrconnuykcaductnW rponwmwignition,unlas.Udq”dtheM wd “i.l ue m o v e d &om the booth md exhaust ducts prior to spraying with the second. Eumplea of dangermu combhations ue: L Deposita of lacquers conuinlng nitrocellulose combined with hishes conUlning drying o h , auch as varnished, oil based stains, air dry aumels, ud primus. b. Blemhing compounds bued on hydrogzn paoxide. hypochlorites, perchlorates. or other ox& dizing compounds combined with my organic --- 15. Chapter 114-AutomobUe &nbhing spray booths w enclomucs.otherwise installed md nulnt.imdIn conformity with NFPA stydardJ,may Jtermtely be wd for drying with ponable electrical in&ared drying apparatus only when conforming with the foUOving: L Interior (especially h r s ) of spray enclosures shall be kept &ee of “ p r a y &posits. b. During spray operations. the drying apparatus a d electrical ronnections and wiring thereto shall not be located within the spray enclosure nor in any other location where spray midue nuy be deposited, E. Spraying sppupars, drying . p p . ~ l rud . vente lptins s ~ n a n of w a y enclonvc shall be quipped with ruiuble interlocks so m g e d uut: (1) Spraying -01 OEM while diying a p p u , tus b Inside m y endoam (2) Spray esclosure will be purged of spray vapors for a period of not less t h m (3) minutes before drying 8pp.rrtus can be cmrgized (3) l W h t i n g s ~ n a nd maintain a d e umcsphere within the mcloavt Sptnethe myins P-d dryingspF”dal“& d l y shut offin the event of Wure of the vensynan A 4 5 In general, eledcal equipment b not prmlaed h i d e m y spray booth, in erh.usc arek,in the ent-ained air of an exhaust qsmn a rpny operation, nor in the direc~puh of spny. A 4 7 Unless separated by p.nitions. the m a within cenain distances of the Iumrdw spray are% ck pending on the m g e m e n t is considered Dmsion 2. Within this distance, electric &ps mlul be enclosed to prwent hot particks &om rpuu\p on combustible materials. A-SZ.1 Spray Booths-When spray booths are pmnad with adequate ventilation, booths m y be LO I* cued with respect to the source of theirrmhup air replacement thu air in the entire sp.rr &out the booth moves toward spray booth e h u d “dead air pockets” are “ised. -re spraying ir conducted inside a spray booth using conventional spray equipment m avenge air velocity of approximately 100 linear FPM should contain overspray. The ventilating inn capacity in CFM must be 100 r e t per minute times the total area ofbooth openings,Le. frond. ma, connyor openings, etc, in spuvc fcer A lower ntc of uhuurventllrcion may be emP l a y e d b W .pnying.Gunnlly,antl of e l h u n of approximately 60 linear feet per minute will keep the atmosphere below the e@& llmlta NFFA No. 70 (Nlaod Ekccrial code) Chrpta 616-2 CIMS 1, Division 1 loutiow--The Interiors of Spray booths and their exhaust ducrs; dl space wlthin 20 feet horizonrally in any direction 8nd 10 feet ve!tiuUy &om spraying operations not conducted vlthin spray booths. b. CLUS 1, Dhrision 2 lOutions-(See i t e m 5 & 6). L VII. OF INTEREST TO USERS AND SALES PERSONNEL: A. CONCERNING EFflClENClESOF BlNKS SPRAY BOOTHS THE M U O W I N G ORDER CAN BE EXTABUSHED: 1. ENVlROTECT WATER WASH SPRAY BOOTH L Moat edlcient and expensive standard cstalog booth b. opaucs u 2 r to 4 . r W C pressure. E. h n t w a t e r c u a h l s s t a m k d . d Dyna Unit is fabricated in welded sections which rqulres le%d o n time in the field. e. Specill dowmhft models are aMilable. f. A hrsh production, lugh cpppeiry washer. 2. NOPUMP WATER WASH SPRAY BOOTH 8. o p e ~ U ( ‘ t o 4 1 6 n Z t i C p r r r a u e . b. Specid wuhen ue available from 600 CFM P e r w fOnI0 W f L L Dyna Unit is fabricated in welded sections rNch mpim less d o n (bm in the field. d. 8ped.l QandRnmodels are N.ilrblt. 3. WATER WASH SPRAY BOOTHS WIM SNLE A, B, C. OR E PUMP TYPE DYNAPREClPITOR uoo . UHITS .:Expense varies by style of 4nr Unit, but is \urullylasthntheEnvimtmud NOPUMP booths. b. Reskunee varies by style of Dyna Unit, but a n be su(ed to range &om .B” to 1.3” rtaric P==Jn. CLinulfeetaprciries (1) ‘A’Style-600 to ZOO0 CFMlh. This Dylrp Unit hrr a low k n l air intak. This feantre k MAfor doamdnit booth opplimion~. 0 ) ‘ BStyle-8000-1800 CFMlft. The most emcient md expensive of these washers. ’IWi Dym Unit has (2) nuniloldr for ddit i d wrrhrng and e5dency. (3) ‘C‘ Style-BOO-2000 CFMlft. Has a high level air intake. Ideal for special height spny boothr. Our monv t l y r i e pumptype unit (4) ‘E’Style-BOO-1250 CFMlft. Our most POP* dnh,PumPtypc Dynn Unit. Catdog itshEconomid in aydprd form. 4. AzfioMorrcrE SPRAY BOOTHS L DOWNUNDERSPRAY Boonis Air ir inOodUCed ud forced through filters at the top of the boo& The air flows ow the vehicle. mund the sides 8nd is pulled downward through the Blter be - IS0 neath the @atln&WWI WYd " f t method the ownpray hu less opporh~nltyto adhere b. (2) Not technically a water wash booth u no m t l r cwtaln exiru. commpentty it is no( mdqdthednbh. intended to compete with water wash DOWNUNDER SPRACURE BOUll@ booths.A direct competitor l o the "Koch Sons" cavity-back booth. Same .wOar principle u Ute Downunderspray booth and the booth is quipped with heaters Smtegidy pOrmoned for proper curing of the coating. special inWlOcka are pmrndcd fm Ute .pnyine Ud wirur eudca. Note:The autoomo(ivc w&m mentioned rbon u e aeldom encountered omside the auto ~~USIXY md are sired md priczdmeaeh ¶pciuarion. e. ~ , F i l t a T Y P e S P n Y E b o t h 8 RP.PaintkrrstorBoMh (I) slightly more emdent (2) slightly more experuhrc d AndreaeNtn'Booth (1) lonee? lasting nltn (2) far superior for certain applications (drm coueeting or PRED usage) W:DmrdDnU boo^ are a d a b l e in e k a dv water wash configuration. A downdraft booth is expensin, but is .Is0 the most emcien: booth smngement available. 5. SPECL4L. USE SPRAY BOOTHS Slimline 'WH" Booth (1) A spedslty booth for the furniture indwry. Or Enerlor 8 W 8 S dmmnsmed 8re derign8led C l 8 u 1. Div 2 hlCIlOt 8 W 8 S 8 I C deslgnaled C h S S 1, DlV 1. Exhaust F i n C ~ P ~ C IIS~ determmed Y by multrplvmg all open Irea l b c c plus conveyor opentnqsl by me desired daciv 1:25 FPM lor open t8ce 000th. 1W FPM tor v8hicIe booth1 B. Air Supply SyJtanr D M - b SysCmrr E"- a. Natural g s s - k a expenrive when aVjC &le b. L P ~ ~ ~ ~ r p B e s Y N m L Stem-Noticeably more expensive than llps d Elecuic-Prohibitively expensive units operate with hea:ing element in thr air mam. Mow a minimum Of (I) week for securing mem or elcetric air supply prices. c. Indirrcl-b system Energy Source Oil-Unit is expensive. Oil requires a S U I I I N ~ ~ * and circulating syslem. Unity do not hyvi. modulnting control companble w ~ T I . ~ W units. Frequently have only "full-half-ofr modvlotion E n s f i f m a t dimensioned are designated Class 1, Div 2 Interior area$ are Class 1, Div. 1. MI. OLOSSAFW OF TERMS USED W E N 0-N SPRAY Eoonis AIr Maks-Up Systsm-Thh b rqulred tu bring In &Mfllvrrd (llllmidined) airtorep~tht.pchrthc Exhaust Wmbor-A devlce tu wmut the enda tk+proof r "into s spny M Exhaurt Fan-The fan b w e d to provlde suftlcient praam tu m(M the l-whd mount ofair through the m y booth ud nvinuin arilldent air nlocity. Explorion Proof Lights-Lighrs which are used in u e r r where dangerous vapon u e present which can QUY explosion or Ure. Explodon Pmof Motor-A qecidty built motor which can be operated in a locotion w h m solvent fumes are preacnL In some aptes this Gpc mom b rquiredon .U V = Y boo& A l t n Door-A door fitted with fflten which yc ured to convea 8 mom or spray booth into a dun tree @ray p.int Rttn 01 Ikv BDoth-A rpnybooth nith &proof di, pos@le paper ffltenwhich trap ovenprayed panicles ber0m.the air b ahalmed to the ouoidc Flkntion Efficie~-Good 5laation b predicnlcd on the spraying ofone @ on I ofpa.int p a foot of booth thm at& eJuuafanhsnmOved h d n a r Fibr-A 3re reurdu\c UIU-C d tm ahccts of perforated cormgated paper of un+ ILe which b attached at the C O M g U I O M . The dlta b mC Lpslble and folds up llke an .crordion When opened & pmvida a winding passage so that the conllrnLvted air rmhs the w.u1 of the d l t u fuuing the *tm stick or dmp out Of the air before bchg UhVlMd 'Ibis mer b rlso disposlbk. Baffle Booth--lhe simples form of .pny booth .SN& = - IKU m e r to distribute the air wenlyulraugh the spny 8 . N Bench Spny Booth-The work area has been ckvated rbove the floor to table height This type spray booth b - vrcdtospnysnlaliitans. Booth Resistance-The rating b determined by the pressam differentid the e l i " rccrionm$ir NLIuRdin inches Of antamhrmh 600th SCnw-A device rmde Of b r o w so It d l IwI( ueue a spark when ured in maping the huvybuUdup of dried paint off the wdb of the spny booth. Canopy Booth-Where a cover is placed over a spraying praacirrguiringthe m o d ofeontuntrvted feetfromtheeliminuorsectlonusingscpndudprrraves for one hour. The exhutsted air b sunpled Md not mom thvr flve rpplns of a p.niculu ryp putide ue to be prraenr In lo00 CFM.of High T m p m t u n Exhrult hnr-haiuust h dc rigned with a rped.l shaft and beuingr to with~tpnd tsnpmtures from 4OTto (WT. Low Rsrirt.no W a a h s n - O p m t e atth a ecoC umn b d i f . c l o n k l o r r.Most audud type tworhs ue brrrsiMncebeuuae-they ut gtnaaUy l o w a i n c o n udlomrh0penLingeosL~ Hioh Retirt.nu W.sh.n--Opcmte with a XUQ miumn indiution .bovc r.The higher the mistance the bencrthe~on~i~oftheboothudthehigh. &. air. C.ramic-lype Spray Booth-A specw type of rpny booth uaed whew cerunic type murri.L, mused mil which pennits the rechation of the ~vvrpnyU 10 dairrd Compound-Additives added to the water which QILIRS the paint particks toeithallou on thesurhce or wdepnding on the typeboothbeing l n e d Reput.ble paint mylufDeomrs ue wulfy able topmvidethe pmp er compound for their'mteriah.When using a high resi9&IIcebmthannpoundsshouldkieptto."ua t o m i d foaming. Heavy weight oii may u "rk used tommimize founmg. Conveyor Opening-An opening in a spray booth which permits work to k allid through Cnnr Ddt-Where the rir enters limn one aide of the booth and the uhuutcd rir ismmondfmmtheotha ' ertheopcntingcorr No-Pump Water Wash S p n y b a t h - A spny booth t h a t w s h & h a i r ~ c e t o ~ u i n a a n t a ~ vriar M.nhld-The pipe which dichibura the vpter to form the c u W n in the eliminuor sedlon of the spny booth. Paint Amstor Filter-A honey combed 5re retardant w ater which mps the paint wcrrpny, used on mter brp spny booths,this item b dwposable. %*TWO M o t a - O N E "EMOTUR WHERE its inner p.nJ are to the ansidc umosphae. Plenum Chmbor--An u e a in which the pressure of the air endored rprce &-.than the wtside - side. unit of meuuring the m h bud. ne= of sound ordinarily detectable by the human UT. The measuring scale begins with number one for the faintest audible sound one can hur. Dispo-Spray Booth-A spray booth with a cloth Dsclbsls IDBI-A uta which uaps overspray. DownlDratC Watsr Wash Spray Booth-??& spray boculmom the m n p n y Md paint lumattKougha grating on the Ooor. This is the cleanest spray booth available for doing tlm Drafc Gauge-A device w d to m e " the prryurr d.i&mlIiai 94055 the BlterhnL and indicuawhenltis time (0 ch.nge the d l t e ~ . Eiimirator Section--lhe part of the booth where the -lid 7articles are mnond fmm the exhaused air. umw==. Somi-Dratt S p n y hoth--whm the air enters from the top and is ~xhausedthrough one of the rides. The . p n y opentor should d e n t himelf so thu the mer.pnyisnotFUwtowudhim SPW B0oth-h uuduigned OI -zany off aerspny and Yumu by of uhawtmg the rir fmm a spray uu 152 Statlc Prorrurr-The mount of resisunce which b pruent In my spny booth exh.ua rystrm. sutic P r e muc wi- aith the mount of air belngmovcd .nd Its dodty, length of suck, elbows. fflters, etc., nut wiU “tion Totally Enclorod Motor-This motor is sealed In w that moisture ud paint pvdcles m o t reach the W e workings of the motor.Recommended to be used on . p n y booths where explosion-pmf moton are not re qulred to conform to (lkuxy Mutual) rqui”m Stripable Coating [Booth Coatlng)-A coating spayed on the WPlLs of the spray booth before It la uecd ’ h i s coating vill simplify the r a n d of paint buUdup d h v w . Touch-Up Spray Booth-This la a very amdl type bench spray booth used to spray very snull ituns. Not Itcommcnded for poduetion. furntoblo-A rotating table to provide access to dl mder of ynu produn UpDntt-Where the lir enten h m the bot” of the booth ud u elhauslcd h m the top. Vapor l i g h t Lights-One type of lights that are endosed w thot dangerow vapors are kept I”the wvrng of the hght dmue. Varsol-Typo Spray Booth-A specidly built spray booth for r o h m t degreeumg ud c l e m g of pans m L booth.Solvents are rrelpuned ud recirculued. Watar-Wa~hSpray Booth-A SpnY booth thu has 8 water curtain whch cames the omspw purrcks into a coUechng pan. lhir spray booth removesa large qumuty 01omsprtly perricles &om the w. It is also the d e s ( method I ”to prrnnt fim. Weir Platr-A plate which holds the h d g e in front of the booth or m a holdmg areado LhU the overspny pant particles may be removed SELECTING A SPRAY BOOTH IJ Which type of spray booth? WATER WASH-TYPE , Operator Techniques GENERAL DESCRIPTION 11 is possible. unfortunately. when spny printing to do wml things mung m d stlli produet M IE d p u b l e flnlrh. One could then say “So why worry about technique?” The main reason is COST. Poor apnying techniques “It in the use of exetssive mounts of material m d perrcnri energy. ?his leads to hither rejection of the p m duct due to a poor final finish. me use of pmper technique is easy to develop. It is a matter of developing a good technique into a habit. Just as bad spnying techniques M leuntd, good techniques M be learned just . Ieasily. In the following outline. we will explain the basic principles of good techniques for spray painting with aides or conventional equipment. Note: The% are only starting points. There are excep tions to every rule and these exceptions will be determined by the individual job. BEFORE YOU START TO SPRAY The rpny run md 111 related equipment should bc dean and m proper working order. The spray p n should be checked to see that it produces a p m p r spray pattem. A proper spray pattern should be uniform in shape. panicle size. and panicle dismbution, with dearly defied boundries. There should be a minimum mount of partially atomized random puticks outside the spray pattem boundry. Keeping pressures low will aid in the formation of a conen and uniform spray pattern with minimum off. spray and rebound. $:: .. ,. . ::A(? i.2.;. @d ~ AIR TYPICAL SPRAY PATTERNS 1 d AIRLESS SPRAYING PRESIJRE A h o p Atomizing Pressure Is: 1. l b e minimum air pressure needed to atomize the fluid properly.* 2 An rir supply which will provide rufficient volume (cfm) of rir to operate the nir nozzle efficiently.* *For internal mix nozzles. atomizing pressure is in balance with the fluid prtvum a i the spray gun. 8. Propsr Fluid Prmura Is: I . The minimum fluid pressure needed to supply sufficient fluid to the spray gun to meet production requirements. 2’For intemal mix nozzles, fluid pressure is in balance with the atomizing air pressure at the rpny gun. 3. (With drlesr) the lowest possible fluid pressure which will 8tomize thr material PropcdY. C. Rulc of the Thumb for Setting Plosurcs ’When the Spray Pattern is Right-The Pressures arc Right” (provided the lowest psstble pressures are used). D. 0 t h Faetoo The above rule will pen. erally get you started. but other factors that contribute to a final finish of high quality are: 1. The proper flowout of the fluid on the work. 2. The proper drying. curing. seninpup. or baking of the fiish. - *Not required for airless %prawn$. tV. SPRAYING TECHNIOUE A. G”l 1. Always have the spray gun in moilon be. fore triggering. 2. Keep the spray gun at the same distance from the work. 3. Move the spray pun aaoss the work at the same speed. 4. Always trigger the spray gun at the begin. ning and end of each stroke. 5 . Sun the first stroke at the same point on each similar object. 6. Put on a full wet mat whenever possible. I. Always overlap t h e previous stroke b! the same amount. 8. On similar pieces or work, always U Y rhr m e number of nrokcr or pasrs. 9 . End the last stroke in the same piace on similar objects. B. Spray Gun Distmcl 1. Spray pn distance from the work should be approximately: a. 6 to 8 inches. 01 the span ol your hand. for conwntional equivmcnt. 4. Avoid "heeling" or '%eing" the spray gun. Move your arm perpendicular to the work surface. b. I ? 10 15 inches for airlesssDravinp. . . IO lu I ? inches for electrostatic spraying. 2 Move the spray gun closer for a wet. dark. I i c i q . film build. 3 Miwe awa) from the wori. for a dry. I+?hl. film build o r for a mist or dust coat C. 5 . Overhp a portion of the prewous stroke approximately: a. 50% for conventional splsying. b. For airless spraying, overiap only that m o u n t which is required to flll in and cover the prrvious stroke. or about 25%. ,-Aim fin1stroke at pami edge C. Stroking I. Move the spray gun parallel to the work. 2. Keep the spray gun at 90'. oral right angles. to the work surface. I 6 to 8 inch- / ' I ' ' r \Coatlngshould kden and m when spraying - ..-Stan stroke o"ersPrav without "banding" 6. Crosshatch overlap for a uniform coat when required. Use vertical strokes first. then horizonul strokes over the m e ma. 7. 90U. gun travel gives a he3". wet. film build. 8. High pun travel gins a dr!, I l g h . fdm Right - build. D. 'Trimring" is Neded to: 3 Avoid "arcing" the spray gun. Move your arm and shoulder, not just your wrist 1. Keep the nuid nozzle orifice and air. less tip dcm. Build.up offluid on the flu. id nozzle orairlev tip may cause the spray gun lo deposit a heavy "blob" of paint on the work. 2. Reduce paint loss. 3. Prevent heavy build up of pain! on the corners and edges of the work 4 . Prevent possible runs and up 31 tllc beginning and end of the stroke. 5 . Give the air.operatcd pump a chance to catch up in deliver! and mainiarn p r w sure. t d a t i n g Will be Carting will be b v y I t this light at this point , Wrong 156 . 1 E.T.chniquM e a N d l d to Cow Trpiol I . "Bud" the c d ~ e sof the product t i include corners and pronounced con. to IOUR. d. Interior corners i. Spray band 11 edpcr. ii. Work out uf coriicrs. i1i.h not spny directly into1 comer. a. Flat panels i.Spray bands at edges. ii. Fin& panels with iioruontd strokes. Wrong b. Table edges (ovenpny and rebound should fall toward unpainted surface), 2. On long work, bmak the disrrncc down into 18 lo 36 inch strokes. Remcm. k r to trigger the rpny gun at the end or each.strokr and to feather the edge of pattern. Exterior comers (should be painted rust). E. . . uncoated panion of parr being spravec dI sham a n be coated Ihc same Way. Each ObJea must be analyzed and the simplest. most drrcci. method should 4 . No1 d. Special - be used. Some typtal problem sham arc: a. Open work Rotating work holder 5 . MOVEMENT of the spray gun over the product should be uniform. b. Round RIGHT, lust three stroks to cove C. Slcndcr V. CHECK LIST OF VARIABLES CONTROL. LING OUALITY IN SPRAY FINISHING A. Atomization I . nuld nrcoslty. 2. Air pressure. 3. Fan pattern width. 4. Fluid vcloctty or fluid pressure. 5 . Fluid flou rate. 6. Distance or spray pun from work. 0. Evaporation from SpnW hrl I . Surface temperature. 2. Ambient air temperature. 3. Ambient air wiocity. 4. nash time between coats. 5 . flash time after find mats. 6. Physical properties of the solvents ( i t . . fast or slow evaporation). E. Operator 1. Distanoc of spray gun from the work surface. 2. Stroking speed over the work surface. 3. Pattern overlap. 4. Spray gun attitude a. Heeling b. Toeing c. Fanning S. Triggering B. Evaporation Raw 1. Physical popenies of solvents (Le.. fast or slow evaporation. 2. Temperature a. fluid b. Work c. Air 3. Exposed area of the surface sprayed. C. Evaporation B n w a n Spray Gun and Sprayed Pan 1. Type or reducing went or solvent. 2. Atomization pressure. 3. Amount of reducing agent or solvent. 4. Temperature in rpny m a . 5. Degree of atomization. VI. VARIABLES AFFECTING COLOR IN METALLIC FINISHES I I To Make Colon A. ShopConditjoru 1. Tempenrum . 2 Humidity 3. Ventilation E. ' Increase Decrease knme lncreur Increase Decnnv Smplln More air DcefFue Increase increue trgrr w air Faster lncre'ase Do not use Slower Decnw Increme Increase Increme Will not lighten Wrew Spray Equipmm and Adjustmono 1. Fluidnozzle Air nozzle Ruid now Fan pattern width Atomization prmure 2 3. 4. 5. 1 i lnrnnw Dwreasr Dcrrenv C. Thinner 1. Type of thinnrr 2. Reduction ol color 3. Us+ of reruder Add rrtardvr D. SPrayinp Tehniques 1. Gun distance 2. Gunapeed 3. Flashtime 4. Mitnwt 159 . LkWW knuw Weltrr coat mirl I! I VII. 'COMM'DN TERMS USED INCONNECT~ONWITH SPRAYING TECHNlaUES - Air Atomization the p m s s by which jets Of air strike the fluid stream and break it up into finely upanted panicles M that the fluid can be distributed evenly. - Air Rasure the d e p of f o m or power at which the air is tnnsfered from the air compnssor to ppny gun and then to the spny nozzle. Pressure should be kept at a minimum yet high enough 10 give you the desired amount of atomization. rpny pattem, and finish that you require. - Fan Shape or Pmam the resulting shape or design Y the atomized particles begin to build on the work surface. Using the fan control or side port control of a spray pun, a narrow fan may be p r o duced for edge.work and a wide fan for flat work. Remember. 8 narrow fan puts more paint in a small. e1 area. so you either have to work laster or cut back on the amount of fluid with the.sprry gun needle valve or by reducing fluid pressure. - Fluid Pressure the d e p e of Iorce or power at which the fluid is delivered from the container to the fluid nozzle. Pressure should be kept at a mini. mum yet high enough to deliver the amount of materid which the opentor a n hmdle. High fluid prwure causes high fluid velocity which makes It more difficult to atomize the material. If loo high (maximum 18 psi at spray gun) fluid prmum is nerrrury b satisfy your fluid need%a I q r orifice nuid n o d e should be used in the s p n y wn. - T r i w i n g the anion of turning the gun on and off. This should be done at the beginning and end' of each stroke. - Stroke a sinerr movement of the spray gun across a spray area (normally not more than 36"). Similar to the stroke of a paint brush. Ram - the number of repeat strokes which arc required to cover the object. - Gun S p e d the s p e d at which the spray gun moves over the work surface. - the disiance the gun should be Gun Dirunrz heid away from the work surface. - *ling and Taing the tilting of the spray pun so the spray pattern IS no longer perpendicular to the work surface. This causes a heavier build-up of fluid at the bottom 01 top of your stroke. Fanning or Arcing -waving of the spray gun back and fonh across the work in an arcing motior thus changing the distance of the spray gun IO thr work and causing uneven coaling and excessive 10s: of fluid due to over-spray. C a t -the total amount of material applied prior to flashing off. - Tack Coat I lirht coat of fluid put on the work 50 that later a heavier coat CUI be applied without the fluid sagging. - Mist C a t I final c a t of appmximateiy 1W solid and 90% solvent used to "re-flow'' the prrvious colt. - Film Build the thickness of the fluid which has been applied to the work. The toW amount or thickness of fluid adhering to the surface. Full uwt - full-bodied wet coat requiring one or more p a s . Flash Time -the Mnimum time it takes for the sol. wnt to leave the sprayed film before it is read) for recoating. - Om-bpping the process of panidly covering the previous sprayed stroke. usudly given as a PI. enrage of new coverage (example 505 lap. 25: lap. ere.). - - Enpornion the release of solvents from the fluid inlo the atmosphere. Vaporintion F. the process of turning liquid inin - CrwMching the same as over4apping. except done in alternating venical and horizontal d i m . lions. Om.Spay work. - that fluid that is lost by missing t h e - Off-Smv that fluid which is lost due to bounce. off or deflection. .. F b W 8 . D * I . D W C V $ Reprinted by Binkt with permissm from Wood (L Wood ProductslNovember 1990. HOW TO MAINTAIN A SPRAY GUN A step-by-step guide for proper spray gun maintenance BY J.W P. Hund BlnM yfg. co. A prowrfy mantamed spray should w o e N user wim years 01 Latslaclory s."e Fauny spray panem can be the resuii 01 an mproperly adlusted w poorly mainlam spray gun H 6 a precsion IWI and deserves tne same care and anention Pat any crabman gtves the look wth ~ l c he h m a k e ha livlnp Marrrtacluren 01 spray guns repon lhat m e often than not. mvestigalm of com plamn of dBlectwa spray guns usually reveal mprow care or abuse h adeffw a w a y gun to conuStently poha PualQ rcwlcr. d W receive Im, typer of mantemme Fm. I( shordd receive a i l y rnamlenam wch as b@t hwatKn and dcanno scccrdly a corn *le omtaul6 meuary after a p l o d 01 m a w s e w e Regardless 01 the spray gun tvpe (aa a u m . an asssled an&. nMP. ctcl cr manulacwn. all requnc proper mamlenarce This a m k mll emDhasue the rum mendeo daily mintemme procedures of a sway cum Fvsi IC! s estabhsb haw rot to t e a l a w a y pvn Never totally submerge or soak a w a y pun m a conlalner 01 sct vent Dong so fills the gm s mtemal air and M passapways vim dKI contammaim bose Dam1 mnlcles resldue e t When the solvent 6 remved oflen much 01 the cmlamtm slays behlnd 10 Unmlely P l q Up the gun S OrifCB Of 15 &lodged l k w h Ihe air nome and enters the spray coaltnp causiw Mm delecls Soakmg a m y gun m solvent also removes all necessary kincabon of (he mecharml pans R M destroys pack@ &mer than a c[xIF W e soakng. umply rcmove noatcs and hps ard soak these pans separately tl w k n g 15 necessary lo remove meSe cwnpanenls. w h e r p e only me atlected areas k e e p g the way gun packin0 and gun rJeS out 01 me solvenl &rand M m?zks.. tlnd neems. and aides t@s shadd receive vbnosl care when cleamg New use any!luq harder than tiass lo uaxlp clooped an mz!e pasrapeways u t&s Tunps(en c a m aides and an asyned a u k s l mare very kmk and I& 10 beak easly A SMI bnr- LUBRICATION POINTS OF A TYPICAL SPRAY GUN are r e m e d . piow3 clbncatl~6 n MdW. dOp Of llpmwelphl MI ShYJ!€I be @aced on the needle valve where IIenters the (kad packng p s t ahead 01 the bigw (Uluslratmitem 2) Tho nul. more CD"0nly relened to as the neede packbq gknd. s h 4 3 never anow the pcktnp nude to cry out u do solve n ma OCM. IrrbnCale u replace Controlling film thickness of coatings-on wood H ' ow important is film thickness control to the application and performance properties of coatinp? hi051 suppliers of metal finishes ind the manufacturers who use these. mducts have no problem answering ,his question. The thin. dry film of paint (0.001 nch or M) which protects the metal ,an from w a r and corrosion also wovides the aesthetic properties of alor. texture and gloss to a myriad if metal i t e m from bottle caps to pact vehicles. The amount of paint ipplicd influences all of'thesc proper- *7 - I / 40.00 ia. Sophisticated application q u i p Rent is often used to transfer the tinih to the metal surface in a precise, conomic manner and the dry film hickness of the coating can be fairly. ccurately monitored by electronic or iagnctic instruments. In sharp contrast, the application lethods used in most of today's wood irniture and cabinet manufacturing lanu. arc manual spray (either con:ntional air or airless type). Wet or ry film thicknesses are seldom, if rer, measured. I t appcars that the present mcthis for applying coatings to nonconictive wood surfaces will not iangc dramatically in the immcdie future. Application equipment suppliers. iatings manufacturers and w d rniture and cabinet producers coniue their cooperative efforts to im. 'ove the transfer efficiency of wood utings and these efforts hove met ith some success. In the meantime. however. steps .n be taken to BPDIY and measure. fith some degree. of accuracy, the Im thickness of coatings on wood. nformation on some fairly inexpenIVC. wet film gauges can be obtained Wid. 10% 15% 2-1 '2 Mila 320 20.* 480 640 25% 800 3 0 . . ob0 55% $120 1280 1440 (boo 1760 60% 19M 65% 70% 2080 35.40.* 45% w. 75% 80.. 85% 00% 95% 2240 2400 2560 2720 160 240 320 107 160 214 96 480 350 394 695 520 415 748 560 450 800 600 480 854 640 680 720 Y5 560 640 720 800 880 960 370 425 480 S O 586 640 1040 1120 lZ00 1280 from your applications quipment or coatings supplier. Once a method for testing the film thickness is established. follou a few 64 4w 260 100.- t 20 160 290 240 280 320 128 160 192 224 256 288 320 *oo 480 1360 1UO 80 P O 906 %O 360 uo 510 575 608 640 simple rules and you are on the n to reasonable control of your tini operation. Don't try to monitor the thic such as low aolids ruins or tonm. 'rhw a x urunlly applied in very thin film and absorb quickly into the wood. Primers, basecoats or enamels should all be measured. Measure all clear films such as washcoau. sealers and topcoats and take the measurement in the spray booth, immediately after each coat is applied. Explain the purpose of your tests to the spray operator. Remember. be or she has often k e n spraying for a number of years, without guidance or controls. Your initial goal is to measure &e film. as it is presently a p plied, to determine whether or not it should be adjusted to pro. vide optimum propeniu to the finished pan. Work with t h e sprayers to achieve consistency. The important thing is to apply the same film thickness. time after time. aeU Of WIor a u U 9 It's surprising how m a n y sprayers M be trained to apply wet film. within i range of 0.001 inch. mnually. Once good spray techniques ' have teen developed, run some test picces to determine the right amount of mating for your product. Do not change the established spray techniques in order to achieve desired film thicknesses. Instead. anlit the services of your applications equipment supplier and matings manufacturer to optimize the fluid Row rates, tip sizes a d viscosities necessary to achieve desired film thickness in each spray operation. Keep in mind the f a a that variations in film thickness greatly inRucncc almost all of the appcarancc and functional propcnies of the wood finishes package, which protects and enhances the beauty of your pro- dun. In iencnl. a total dry film of 2-3 mils of coating it sufficient to provide the daircd appcarancc and performance quilities IO properly prepared wood substrates. Excessive film ~hicknesr.espccially on horizontally sprayed surfaces, may well k the caux of such p r o b lcms as blisters on open pored woods. lack of clarity after :he finish is rubbed and finish checking years after the produa is in the field. In summary, stan controlling the size of that protective envelope which contributes 50 much to the saleability of your wood furniture. kitchen cabinet or T.V. console. Oncc you establish the proper film build ncedcd to maintain the desired quality of your produa. keep it conrirunr. Finally, k sure you're not appl>ing more material than needed to develop the finish propenics you want for your merchandise. 0 WET FILM THICKNESS GAGE I= 0 - Acid catalyst iacqueesL q u c r r a d l y d e of urea formaldehyde. melamine, and epoxy resins. set by polymenntim. Alhd plnrticuen increase resistance to water and heat; Standard i s the two-component lacquer. made of lacquer resin and a separate acidic catalyst. which could consist of hvdrochloric acid. organic acid phosphate. m S A . etc. The pot lift ofthis mixturr is several h w n long. Active solvent-A solvent capable of dissolving a resin by irxlf. Additive-Any substance put into a coaring. usually in low concentrations. that helps cffccr the coating's physical characrerisrics. Among other things an addi. rive may be a colorant. an inhibitor. a pwrvative. or a stabilizer. An - umml chat uses activated charcoal to WLorb VOG from the qmy booth exhaust. concentrate the solvents. and present them for either disposal or combuxm vhich ring-hped molecules form the compound. wullly diuillcd from ccal ur.They ~ m t l y , u wd c but at rclariwly Iw Iweb. Two common ammatic hydrocarbons compounds are toluene and -le. A i r . d airless a"Bindcr--An ingrcdmr in a tioa-A method of spray application that combines soin d u t a l l w the pigment fo hold a sum in place when ainpny and airless tcchnolodzy. and gives the stain the g l a It d u e s the fluld plaSUR common to airla, s w right adhesiveness for a fin. ish. For example, a lacquer rems and uses a small binder producer a stain that amount of atomizing air to can k spongedncd quickly, aid in atommnon while an oil or varnish binder n u k e a wiping stain Airless atomization-A method of spray application chat u n k sprayed. dipped. or brushed on before being that atornuts the finsh flud wiped OH by pushing it thmugh a small onfice at high prruurc It ha transfer diciency dlpproxi- Bleached woods-Woods trcatcd to be light-colored. marely 50 percent: known Most frequently used for iu high rate of rped ycr bleached woods include m e w h a t coarse fin& blonde mahogany and blonde walnut, which are Airspray (see Compressed poplar as cabinet wccds. air otommtion) Adsorption technologvAromatic hydrocarbonsPowerful liquid solvent in I* A Bleaching-A process used to lighten wood when new colon and shades are & i d . BlinabDdectr in finlrhed dproduco, U5ualh elevations on the suriace. that lodr like skin bllrrm Usually caused by the wood s u b king coated with something that doesn'r mix well with the chosen lacquer. also owed by mwd air. water. or ". Blonde finishes-Darker w d char have k n arnficiallv lightened Blonde shades include n.hite. eggshell, cream beige. and lqht bnnvn Blonde treatment-A finishing technique that UKS a transparent rubbed finish to ?CCCl!tUate the W d S N t U nl p i n panm Blush-Milky appearance in film c a d by the condew. tion of airborne moisturr in a film cooled by evaporating solvmu The cloudiness ma\ Catalytic incineracionType of incineration that utilizes a nonprccious meul catalyst to oxidize hydtour. bans at significantly lower tcmpranver to save operatqc m . Cross-link-An atom or p u p joining adjacent molecules in a complex ImcNre making a chemical bond of p o l ~ e Cross-linking ~. can occur with solvent elimination. heat, caulyrinp agenu. or high level of UV dation. Ceramic bed-A type of thenral oxidizer used to canburt VOG in h e p a y Cumin cmdng-Applying liquid fin. ish by psuing the flat subsmtc IO be finished under a thin film of liquid falling by pnnry or ptarmc. bo0rheXh;lurr Finishing Terms the source of the moisture has been removed. diuppev once Bounce-back-The tenden. cy of a finishing material m lppy I O r e w or touncc off io intended nuface. The matcnnl. however. is uught in air M b u l a c c that c a w it not IO mch the surface. Usually a mult of high air prc+rurc in rurpnY. Bridging-The ability of a coating t o cover over an unfilled gap such as a cnck or comer. Bubblcs-Air mpped in the wet film or the paint surface. Typically occurs when film IS excar1vely hlgh. Build-The depth of a substrate given by i t s coating. Expressed in wedmils for wet lquid coatmgs or dty/miL for a cured coating. Butyrate-A lacquer-like. UV-resistant resrn used in situations where good flow and light stabiliry are necesyry qualities. Catalyst-The reactive chemical that starts t h e chemical bonding process when added 10 conversion coatings. Checking-Random cracks in hardened film caused by unFvm shnnking acmu the film’s surface. Temperature dungerdimpqerdqmg between the film’s surface and h e thinner within the flm can cause checking. Cold check-Cndrr f m e d by the expansion and con&on dlmng hot and cold cvda Combustion technologyhcinerator systems that combust. or thermally oxidize. VOCs in the spray bmcharhum.Thecnnbarion .is accomplished using oneddvccryproflhnal Mmu bed. p e l Deep finishes-Finishes that darken wood and make substitutions of differ. cnt v c i c r had to detect. They appm d e in color due 10 hqh film build. Dilumt-A marcrial chat cannor &ISsolve a =in by itxlf but merely diluta the resin material after it is dissolved inm m sctivc solvent. Direct combustion-A type of thermal oxidizer used to combust VCGinthCm bmthcxhwx. Elenrrnadc fin. uhing-A finishing process that e l e c d l y cturp.l :” ppintparridcr that bai.ordirrnc”. when sprayed arc dnwn to the m d t d pam.The coaring ~ V C a Snegative charge and the r~b5uu“ e Ihave a positive charge rbr atmaion m take p k . Compressed air acomiution-A method of spray application that uses come p m K d air to beak up the catmg into mull panicla. E q u i p ” gcncnlly UVI m attached siphon cup or remote prrrwc cup. ranL. or pump for its fluid s u p p l ~ . Transfer dhcimcv gmeralls is low due to h& amounts of air ~ u l c n c e . Cndng-A defect in the film that m y a p p r as tiny cracks or wrinkles. I t is c a d by spraying herh lac. que1 on top of old fuwh. Emulsion cmfing-A waterbased coarmg, a latex. in which min panicles m held drspncd duwghout the warer by means of an emulimg agent. Engineering contmGThe name p e n to methods char reduce V K emission h e r the finuhing pma. Et-An organic compound or number of campoundr made b the reaction of an alcohol with an organic acid or d v d t i d c . has m uud in ninoccllu- low lacquer. Fder-Any arbrtace & m fill hola and inegulantia in planed or sanded S U ~ C KM o r e the application of a coarmg. Finishing Terms a n t d DdhaM of all can m d nher wchm a multi- cat firurh. RJrPSrmllUKhh.". k cud bv Jw dirn d d p. uli. JapnninpThe substicution dpnt for layers of wnrch This technique i s used in Rub piol-l"mn m rhvh, ~ h D r d v r k D u r n v f ~ s O m .Europe and Amenu to CR-0ndUl.nip. hmllrnsrvlhlnnd nTWUk-%dI. NndOn Specks d daldnhpmndauoa.im rmhmdiea netheeffectofonadlac- ustor oil or glycerine p h i . cizers. dissolved in various aromatic hydrocarbon solvents, wd to achieve gccd heat-, water- and spirit-dcohol-rPL(tMt properties. Oil finish-A 50/50 mixture of raw linseed oil and 'boiled" linseed oil used to create a finish that will enhance rhe M& color of Woodrarch Y mahogany and walnut; a close.to.the.wd finirh. -. and induces polynterication. This material commonly is wed in W-cmble f m i e r . Photosensitizer-A substance upable of sensitizing anothcr substance to lays to which it would oot normally ma. %mcnt load-The amount Kctones-Any of a c l w of of dry pigment in a coati%. organic compounds chat ye I& called Solids content. -%--ah of hnuh and h a i c d SUR=*. the charactenred by a carbonyl . rtlvlr d h rmpd bubbh w" grcuparpchedtorarocarbm polvmrr-A large molecule drhMh atoms. For example. methyl chemically formed by bond. G & n r d e p e e W r h r h .aOmq ethyl ketone i s a common Oil paint-A resin based ing monomers. Many times *dlrW&"n. solvent urcd wlrh many fin- catlng coneinlng a surpn. they can bc hnhn reacted uhing materials. It i s verg sion of p i p e n s that form to form luenpolymm. Glycol ethcrr-A type of volaole d a smng lolvau. an opaque film through a oxygenated organic comcombinationofsolwnr evap Polyurethane lacquerpound used in wivenu. most laquer-Coatmg mtenal orstion and the curing oiL (x Gating good for adhesion, commonly in slow-drying that i s based on synthetic flexibility. gloss, and water poly". lacqua. thennoplastic film fonnmg uul chtmical mistance. mataml dlwlved In l o l ~ Orange peel-condition Gnin nirinpThe sulelhg h g LI p n m h h 0 U d - l CIUyd by paor atomization, Pot life-Lsngd~ of time in of wood fibers caused by dnnt MpDernoh improper breakup. or the which a plural component moisture. Not reversible implopr Mponlion of sol- material is nil1 usable h e r OIlCeUlOlmncisgCS%C Lacquer thinner-SubM 1 D ~ f l o v a n o f Cdysis. uarm rhpruMUyccannrs d rhe d m the bGnwl bed-A ryp dthP. shout 30 percent cnm and ing cgclc. The descriptive Print mLtanc+-The abilimJ oxidira wed tocombun ~ O d y s s p V C S J l v Q I L term used to describe the ry d a copring to mdt raklng VOCs in the spray booth diluted with aromatic and bumpy texture common to on the imprint of another exh;lun aliphatic hydrocarbons. thir problem. anhct placed aglmc It. These rolvents are very Halogenated hydrocar. voliflle and should be wd Overspray-Any spray. Radiation curing-The use bons-A group of com. only when d m d not as applied f& not amcred of enqy uavelurg u o i a v e pounds d u t generally form a rubmcun ckaungsolvent morrnwdbyrhepmduct motion for hardening a weak solvents. They are rurface; it is caused by flnuh. found most often in Lifting-A topcoat pullang i"per I p n Y tcduusue degteascrs and arc most away froln a tPceccnt due to excessive air or hydraulic Reactive f h h e d o a t i n g effective in removing wax. mcompatibilicy, poor adhe- pressure. This misdirected that hardens by meam of a grease. and oil. May cause sion. or both. Often this f i n d can dcy in flight and complex chemical reaction fue or explosion if m conmct d e m a wnnklal I d on caw &ear if it lands on a to form a polymer. During wich aluminum. the *. M&. the curing process the wet film atsarbs oxygen iron the High.volumc, low-pressure M " - A sunple molcc- P a i n t - h y pigmented mm air. then starts a reaction atomization-A finishing uLr compound rhat chemi- liquad designed for appliu- that proceeds through the mthcd chat UVI a high vol- cally b o d with another to tion to a subsmte in a thin film. c h a n p g ir f" liquid ume of air at low p u r e for form a polymer. layer that converts t o an to wlid. atomization. This decreases -ut solid film a k a applithe fluid's forward vclocicy Niaoccllul-A group of cation and culmg. Rubbed finish-Finuh thar and increases mnsier effi- resins used in lacquers for results from posr.finishing ciency. Also known as clmty. q u i c h of ~ drvlng, Patina-A surface texture cpentions rtut mechaniullv HVLP.Typically defined a5 and rrpayabihry. produced by age. wear, or mwrh. flatten. and p o l i a atomization at less than 10 rubbmg. flat surface. rypicallt. tablepi. Nitrocellulore lacquerstopr or other hon-onol surCocrtrng composed of niuo- Photoinitiator-A material faces. The process is wed to Intercom adhesion-The cellulose. alkyd resin. and h t h r b s impingw lighr 166 Finishing Toms or aglcared k m a tncmsmgly chin coior and protect a wood surface by formmg a film. obmm ~ r rhigh l gloar IcveL. Sandabiliry-The ease with which a c a t i g can be d e d without dragging or gumming the sanding medium. dry" matenalr. Sanding rulers-Fastedrying solvent. relclu mtcruL wd on bare wood to fdh e porrr and level the anhce More Stains-A material that can cause wmd to color ro &ram effccu of color and gram ddmition. applying any &I Toner-A lowsolids. lightly pip. mcnted stain usually contains bmder. Solvent-release finirhes-Coatinp (such P( shellac or laqun) chat f o m a miid film upon evapontion of the 101. vent ot thinner. Typically called "air - Tnnrfcr efficiency-The total mount ofhuhlng mtmal that lcava the finish application apparatus compared to the amount of fmuh chat acmally rndr up on the pur. The value SI exprerred as a percentage. The higher the transfer efficiency. the less costly the h u h m g wrem d b e ro operate fiiuh Sealer-A coating that can slightly raue the woodgrain fiber and seal the rvmd Upon sanding it leaves a smoorh surface and provides a nonabsorptive surface to apply rhc next hturh coatmg. Shrinkage-Usually assocnted with exrnuivelg uau-linked films, vuiblc rhc amount of curling induced on the subsnare Solid color s-aque stam that arc a surpnslon of pigmenu m nthn a dving oiUorganic solvent muwe OI a water/polymer emulsion designed to Strippingdcmoving the old finish hasurface. Synthetic Iacqucrs-Coatings that greatly increase heat. water, and spinr resistance and have tough films and gl= w Ultnviolct-Radiant energy beyond the visible r p c r " at the violet end; =vel+ h shorter than visible light dlOneerhXray* Telcgnphing/ghosring-The rransmithng of surface mcgulanner in a b0~0ma t through to a twoat. UV -The rrcarliing of a macerial upon iB urpoarre to uimviolet ndi- Tbixottophy-A characteristic that describes a fluid's behavior. A thuonuph~cflud typially u v n y thick a heavy &n xren tix when pumped aum W -The resisrance a c u d ftlmhp)IDyco ~r challung whm aeparad to ulmvioln dium. V i T h e degree to which a coat. ing mire flow OI movemr. VOC-The weight and/or content of volatile organic Mnpound (solvent) in agallcnofccating. Vduilc--Anv material rhat can evapom e undu nomvrl condiuonr. Washcoat-A lowv-solids coating applied under a scam to limir p c m . ucn of rhe pigmenrs mto rhe w d . Wbirkering-A process rhat helps elimuute gram rauing. F m the surface d the wood u wt. then flamedned to d e the fibnus mdr c a y to remove. Wnparound-In clectrosraric finishing. finish pamcles are drawn to the mvme 01 bck side of the subsware due to clecnomatic amacuon. bnu nu"for h~mnck U I I ~cmmbturd h:1- Hund. B& Mrmvinrcmg Co.: Thomas Ellis. Chrru S?sccmi Inc.. John T d .DcVilku Fk"g I&md C w w w: MbM ~Grnro. .I=.: " d hW m .iJ&IndUnnu. Ix 8lW2. DI1u COmmun~tm.1%. e., ........ -