helpful hints -...

132 ingersollrandproducts.com

Helpful Hints Compressed Air

Thenormalstateofair,barometric,iscalledatmosphericpressure.Whenairiscompressed,itis

underpressuregreaterthanthatoftheatmosphereanditcharacteristicallyattemptstoreturnto

itsnormalstate.Sinceenergyisrequiredtocompresstheair,thatenergyisreleasedastheair

expandsandreturnstoatmosphericpressure.

Aircompressorsweredesignedtocompressairtohigherpressuresandharnessthatenergy.

Unlikeothersourcesofpower,noconversionfromanotherformofenergysuchasheatis

involvedatthepointofapplication.Compressedairorpneumaticdevicesaretherefore

characterizedbyahighpower-to-weightorpower-tovolumeratio.

Notasfastaselectricity,norasslowashydraulics,compressedairfindsabroadfieldof

applicationsforwhichitsresponseandspeedmakeitideallysuited.Wherethereisanoverlap,

thechoiceoftendependsoncostandefficiency,andairislikelytoholdtheadvantage.

Compressedairproducessmoothtranslationwithmoreuniformforce,unlikeequipmentthat

involvestranslatoryforcesinvariableforcefield.Itisautilitythatisgeneratedinhouse,so

ownershavemorecontroloveritthatanyotherutility.Inaddition,airdoesnotpossessthe

potentialshockhazardorelectricityorpotentialfirehazardofoils.

ingersollrandproducts.com 133

Reciprocating Technology

Reciprocatingsingleactingcompressorsaregenerallyofone-stageortwo-stagedesign.

Compressorscanbeofalubricatedoroil-lessdesign.

Inthesingle-stagecompressor,airisdrawninfromtheatmosphereandcompressedtofinal

pressureinasinglestroke.Thesingle-stagereciprocatingcompressorisillustratedintheFigure

below.SingleStagecompressorsaregenerallyusedforpressuresof70psi(poundspersquare

inch)to135psi.

Inthetwo-stagecompressor,airisdrawninfromtheatmosphereandcompressedtoan

intermediatepressureinthefirststage.Mostofthatheatofcompressionisremovedasthe

compressedairthenpassesthroughtheintercoolertothesecondstage,whereitiscompressedto

finalpressure.Thetwo-stagereciprocatingcompressorisillustratedintheFigurebelow.

Singleandtwostagereciprocatingcompressorsarefrequentlyusedinautoandtruckrepairshops,

bodyshops,servicebusiness,andindustrialplants

Single Stage Reciprocating Airend

Compressed Air - Reciprocating

Two Stage Reciprocating Airend


Compressed Air - Rotary

Rotary Technology

Rotaryhelicalscrewcompressorsutilizetwointermeshinghelicalrotorsinatwin-borecase.Ina

single-stagedesign,theairinletisusuallylocatedatthetopofthecylindernearthedriveshaft

end.Thedischargeportislocatedatthebottomoftheoppositeendofthecylinder.Astherotors

unmeshattheairinletendofthecylinder,airisdrawnintothecavitybetweenthemainrotor

lobesandthesecondaryrotorgrooves.Asrotationcontinues,therotortipspasstheedgesofthe

inletports,trappingairinacellformedbytherotorcavitiesandthecylinderwall.Compression

beginsasfurtherrotationcausesthemainrotorlobestorollintothesecondaryrotorgrooves,

reducingthevolumeandraisingcellpressure.Oilisinjectedaftercellclosingtosealclearances

andremovesheatofcompression.Compressioncontinuesuntiltherotortipspassthedischarge

portingandreleaseofthecompressedairandoilmixture.(Cutawaypictureofarotarymachine)

Rotary Screw Airend


Air Treatment Technology

Oncecompressedairiscooled,furtherdryingcanbeaccomplishedthroughtheuseofa

compressedairdryer.Therearemanytypesofdyers.Dryerscanbetypicallygroupedinto

twomajorcategories:refrigerantordesiccant.Thedesign,performanceandcostofadryerwill

dependupontheapplication.

Withadesiccantdryer,watervaporisremovedthroughabsorptionandadsorptionprocesses.

Intheeventcompressedairlinesareexposedtotemperaturebelow32°F(or00C),theuseof

desiccantdryerisrequiredtoeliminatethehazardofcompressedairlinefreezing.

Refrigeranttypeairdryersarethemosteconomicalcompressedairdryersintermsofinitial

purchaseprice,costofinstallation,andoperation.Withinarefrigerantairdryer,compressedairis

cooled,watervaporiscondensedintoliquidwaterwhereitismechanicallyseparatedanddrained

fromthecompressedairsystem.Refrigerantairdryersaresuppliedwithautomaticcondensate

drains.

Note: An aftercooler and/or dryer can be supplied within a stand-alone air compressor

package eliminating the additional field expense of installation (piping and wiring).

Aproperlysizeddryerwillpreventliquidwaterwithinacompressedairsystem.Alldryersare

ratedforinletconditionsof100°F,100%relativehumidity,and100psi.Increasinginletpressure

andloweringinlettemperaturewillimprovedryerefficiency.

Onceliquidcondensatehasbeenremovedfromthecompressedairstreamthroughtheeffective

useofanaftercooleranddryer,acompressedairfilterisrecommendedforremovalofsolid

particulates,aerosolmists,andgaseousvapors.

Acompressedairfilterisdesignedwithareplaceableelementthatallowscontaminantstoimpinge

upontheelementssurfacearea.Astheelementbecomeswetted,filtrationefficiencyactually

improves.Asliquids,aerosolsandparticulatesrandomlycollideonsmalldiameterfibers,the

filtrationprocesscoalescedinvisiblecontaminationintolargerdropletsthatgravitatetothebase

ofthefilterhousing.

Lastly,liquidsaredrainedfromthefilterthroughadrainvalve.Compressedairfiltersare

designedforspecificapplications.Aproperlysizedandpositionedcompressedairfiltereliminates

contaminantsfrompassingdownstream.Anelectricdrainprovidesareliablealternativetofloat-

type,gravity-feeddrainsthatcorrodeandclogovertime.Electricdrainscanbeviewedasalow-

costalternativetomanuallydrainingsystem.Operationofalldrainsshouldbecheckedregularly

toavoidcostlylossofcompressedair.

Air Treatment


Air Distribution

Thecompressedairpipingsystemshouldbedesignedtodelivercompressedairtothepneumatic

applicationattheappropriateflowandpressure.Theairdistributionsystemshouldincorporate

aleak-freepipingsystemsizedtominimizeairpressuredropfromitssupply-thecompressor

andcompressedairtreatmentcomponents-tothepointofuse.Minimizingthenumberof90°

elbowswillmaximizethedeliveredairpressure.Itisestimatedeachelbowequatesto25’of

additionalcompressedairpiping.Pipediametershouldnotbelessthanthedischargeportof

yourcompressor.Ifmultiplecompressorsarebeingutilized,pipediametershouldequalthesum

ofeachcompressor’sdischarge.Avoidstraightrunsthatdead-end.Themostefficientdesign

incorporatesa“LOOP”thatminimizespressuredropatanyoneworkstation.

Differentmaterialscanbeusedforcompressedairheader;materialsincludesteel,blackiron,

stainlessoranodizedaluminum.Itiscriticalthatthematerialbeinginstalledhasapressure

andtemperatureratingwithanappropriatesafetyfactortosupportthecompressairpressure

requirement.Donotunder-sizepipe.Thecostdifferentbetweenonepipediameterandthenext

largersizeisminimal.Thelargerthepipediameter,thelowerthepressurelosswillbedueto

friction.Alargerdiameterpipeallowsforadditionalcompressedairduringpeakuseperiodsand

positionsthesystemforfutureexpansion.Thecompressedairvelocityinthemaindistribution

headershouldnotexceed30ft/s.

Acompressedairdropleg,alsoreferredtoasafeederline,beginswithaTEEassemblythat

directsthecompressedairinaverticalpath.Thisuniqueflowpatternwillguardagainstliquidor

particulatecontaminationpassingtoapneumaticprocess.

EachcompressedairdropshouldincludeaTEEdirectingcompressedairsupplytoitsspecifieduse.

Thebaseofthedroplegincorporatorsadrainvalve.EachdroplegmightincludeanFRL(point-

of-usefilter,regulatorandlubricator).


What are you using the compressed air for?Thetypeofworkyoudoisprobablythemost

importantfactorindeterminingcompressorsize.Doyouintendtouseairsixhoursperday/

fivedaysaweek,oronlyoccasionally?Areyourdemandsforcompressedairrelativelyconstant

duringtheday,ordotheyvarywidely?Purchaseacompressordesignedforadutycyclewhich

equalsorexceedsspecifiedrequirement.

Where will the compressor be located? Outdoorapplicationsrequirespecialprotectionagainst

waterandfreezing.Indoors,sufficientventilationiscrucialforsuccessfuloperationsincemost

reciprocatingcompressorsareaircooled.Don’tputthecompressorinacloset,forexample.

Placethecompressoratleastthreefeetfromthewalltoensureproperairflowandbesurethe

installationsiteissufficientlyventilatedtohandletheheatgeneratedbythecompressorduring

operation..

How much pressure (psi) do you require? Thepsi,orpoundspersquareinch,capabilityofa

compressormustmatchorexceedthepsirequirementofyourhungriestairtoolsandpneumatic

equipment.Checkthemanufacturer’sspecificationsandpressurerequirementforallyour

equipment.Thepressurealsodetermineswhethertheunitshouldbeasingle-stage(max135psi)

oratwo-stage(max175psi)compressor.

How much air flow (cfm) do you require? Cubicfeetperminuteorcfmisameasureofairflowthecompressorcancreate.CFMisstatedintwodifferentforms,pistondisplacement(PD)oractualcubicfeetperminute(acfm).Alwaysconsidertheacfmasitreflectstheamountofusableairavailableforwork.Readthefineprintandmakesureyouunderstandwhetherthecfmratingis“pistondisplacement”or“actualdeliveredair”ataspecifiedpsi.

What motor horsepower do you require? Horsepowerisdirectlyproportionaltocfmrating

ofacompressor;typically,thehigherthehorsepowerthemoreair(cfm)thecompressorcan

produce.Don’trelysolelyonhorsepowerorattempttobuythehighesthorsepowercompressor

youcanafford.Letyourcfmandpsirequirementsdeterminehorsepowerforyou.Bevery

carefulwiththecompressorsthatclaimhighhorsepowerratingwithlowairflowperformance,this

oftenindicatesan“occasional-use”aircompressor.Theseproductsaredesignedwiththemotor

operatingatmaximumspeed,whichtypicallyresultsinamotorthatwillrunhotwithseverely

shortenedlifespan.

10 Steps to Selecting an Air Compressor

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10 Steps to Selecting an Air Compressor (continued)

What size and type of air tank do you require?Airtankshelpeliminatepulsationinthe

airlineandprovidestoragewhendemandforairexceedsthecapacityofthecompressor.The

largerthetank,themorepressurizedairisavailableforoutput.Thesmallerthetank,themore

thecompressorhastoworktokeepupwiththedemand.Decideifyourapplicationrequires

averticalorhorizontaltank;thisisdeterminedbythephysicallocationofthecompressorand

one’spersonalpreference.Verticalcompressorshaveasmallerfootprintthanahorizontaldesign;

verticaltanksareonlyavailableonmodelsratedupto10horsepower.

What compressor features should you consider? Lookforthefollowingfeaturestosuitmore

demandingapplications:

•100%cast-ironconstructiondesignedforreliabilityanddurability.

•Minimalmovingpartsreducesmaintenancecostandserviceintervals.

•Splashlubricationprovidessimple,reliabledesignreducinginitialpurchaseprice

•Stainlesssteelfingervalveseliminatecorrosionwhileinsuringlongservicelife.

•One-piececonnectingrodseliminateinternaladjustment.

•Oilmonitoringdevicetopreventlow-oildamage.

•Separatecastcylindersintwo-stagecompressorsforbettercoolingandextendedlife.

What are the electrical requirements of the installation? Incomingelectricalserviceisvery

importanttoidentifyandunderstandbeforepurchasingacompressor.Voltagewilldeterminethe

horsepowercapacityavailablewithoutexpensivemodifications.Thestandardvoltageforhomes

is110volts.Thisvoltagewillonlyoperatecompressorsuptothreehorsepower.IntheUnited

States,Canada,Mexicothefollowingvoltagesandphasesareavailable:

•Single-Phase1.110-1-602.208-1-603.230-1-60

•Three-Phase1.308-3-602.208-e-603.460-3-604.575-3-60

NOTE: Always have a qualified electrician review electrical requirements prior

to procuring an air compressor.

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10 Steps to Selecting an Air Compressor (continued)

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What control system do you require?Allreciprocatingaircompressorsrequireoneofthe

threecontrolsystemsinordertoregulateoperationinaccordancewithairdemand:

•Start/StopControlisusedforapplicationswhereairisnotrequiredcontinually,

allowingthecompressorsufficientcoolingtime.Whensystempressurefallsbelowtheset

start-uppressure,thecompressorwillautomaticallystart.Whenthecut-offpressureis

reached,thecompressorwillautomaticallyshut-offandwillnotstartagainuntilthesystem

pressurefallsbelowtheminimumstartpressure.

•ConstantSpeedControlkeepsthecompressorfromexcessivelystartingand

stopping.Aswithstart/stopcontrol,ithasaminimumstartpressureandamaximumcut-

offpressure.Thisfeaturepreventsprematuremotorfailureandminimizesoperatingcosts

associatedwithhighamp-draw.Here’saruleofthumb:ifthecompressorstartsmorethansix

toeighttimesperhour,youshouldoperateconstantspeedcontrol.Ifthecompressorstarts

lessthansixtimesperhour,start/stopcontrolisrecommended.

•DualControlallowsthecompressortooperateineitherstart/stopmodeor

constantspeedcontrolmodebyadjustingthecompressorauxiliaryvalve.Thiscontrolmethod

allowstheusertoeasilyadjustthecontrolmodedependentuponcompressedairusage.Know

yourrequirementsandpurchaseaccordingly!

Additional buying tips

•Allcompressorsratedfivehorsepowerandaboveshouldhaveamagneticmotorstarterfor

thermaloverloadprotection.Motorstartersaresizedaccordingtohorsepoweraswellas

byincominglinevoltage.Thestartercanbemountedtothecompressororbepositioned

remotely.Besuretochecklocalelectricalcodesandrequirementsandhaveallwiringdoneby

alicensedelectrician

•Useofproperoiliscriticaltothelong-termoperationofyourcompressor.Sincecompressors

areshippedwithoutoilinthecrankcase,besuretocheckwithyoursupplierregardingany

start-up/lubekitrequirements.Also,manymanufacturersnowofferextendedwarrantieson

thecompressorifyoupurchaseaspecificlubricant.

•Moistureisthenumberoneenemyofcompressedairsystems.Awidevarietyofmoisture

removalproductsareavailable,rangingfrominlinefiltersandmoisturedrainstoaftercoolers

andairdryer.Consultwithyourlocalcompressedairspecialistregardingyourspecificneeds.


Air Consumption Chart for Industrial Type Tools

CubicFeetperMinuterequiredtooperatevariouspneumaticequipmentatapressurerangeof

70-90psi.

Consumption Charts

Miscellaneous Consumption (CFM) Consumption (CFM) Consumption (CFM)Portable Tools 15% Use FACTOR 25% Use FACTOR 35% Use FACTOR

Drill, 1/16” to 3/8” 4 6 9

Drill, 3/8” to 5/8” 5 9 12

Screw Driver #2 to #6 Screw 2 3 4

Screw Driver #5 to 5/16” Screw 4 6 8

Trapper, to 3/8” 4 6 8

Nutsetters, to 3/8” 4 6 8



Impact Wrench, 1/4” 2 4 5





Impact Wrench, 1” 7 11 16

Impact Wrench, 1 1/4” 8 14 19

Die Grinder, small 2 4 5

Die Grinder, Medium 4 6 8

Horizontal Grinder, 2” 5 8 11




Vertical Grinders and Sanders, 5” Pad 5 9 12



Buring Tool, Small 2 4 5

Buring Tool, Large 4 6 8


Consumption Charts (continued)

Consumption (CFM) Consumption (CFM) Consumption (CFM)Miscellaneous 15% Use FACTOR 25% Use FACTOR 35% Use FACTOR

Rammers, Small 4 3 9

Rammer, Medium 5 9 12

Rammers, Large 6 10 14

Backfill Tamper 4 6 9

Compression Riveter 0.2 cu. ft. per cycle

Air Motor, 1 HP 5 9 12



Air Motor Hoist, 1000# 1 cul ft. per foot or lift

Air Motor Hoist, 2000# 1 cul ft. per foot or lift

Paint Spray Gun (Production) 3 5 7

Hammers

Scaling Hammer 2 3 4

Chipping Hammer 5 8 11

Riveting Hammer (Heavy) 5 8 11

Riveting Hammer (Light) 2 4 5

Saws

Circular, 8” 7 11 16

Circular, 12” 10 16 24

Chain, Lightweight 4 7 10

Chain, Heavy Duty 13 22 31

Air Consumption Chart for Industrial Type Tools (continued)

Alwayscheckwithtoolmanufacturesforactualairconsumptionoftoolsbeingused.Theabove

isbasedonaveragesandshouldnotbeconsideredaccurateforanyparticularmakeoftool.

Abovetoolsareratedbasedupontypical“on-load”performancecharacteristics.

Forotherusefactorsadjustthecfmairconsumptiononaproportionalbasis.

(Example:30secondson;30secondsoffuse50%asusefactor)

CubicFeetperMinuterequiredtooperatevariouspneumaticequipmentatapressurerange

of70-90psi.


Air Consumption Chart for Automotive Service Shops

CubicFeetperMinuterequiredtooperatevariouspneumaticequipment,foraverageserviceshop

usagefactor.


Equipment Air Pressure Range in PSI Compressor cfm Required Per Unit

PortableTools

70-100 **Air Filter Cleaner 3

70-100 **Body Polisher 20

70-100 **Body Sander (Orbital) 10

70-100 Brake Tester 4

70-100 **Carbon Remover 3

90-100 Dusting Gun (Blow Gun) 2.5

70-100 Panel Cutter 4

70-90 **Drill, 1/16”-3/8” 4

70-90 **Impact Wrench 3/8” 3




70-90 **Impact Wrench 1” 12

70-90 **Die Grinder 5

90-100 **Vertical Disc Sanders 20

90-100 **Filing and Sawing Machine, (Small) 3

-100 **Filing and Sawing Machine, (Large) 5

90-100 **Burring Tool 5

Tools

125-150 Rim Stripper 6

125-150 Tire changer 1

125-150 Tire Inflation Line 2

-150 Tire Spreader 1

125-150 **Vacuum Cleaner 7

Hammers

90-100 **Air Hammer 4

90-100 Tire Hammer 12

125-150 Bead Breaker 12

90-100 Spring Oiler 4

Guns

90-100 **Engine Cleaner 5

-100 **Paint Spray Gun (production) 8

90-100 **Paint Spray gun (touch up) 4

90-100 **Paint Spray Gun (undercoat) 19

OtherEquipment

120-150 **Grease Gun 3

145-175 Car Lift* (air powered hydraulic) 6



Air Consumption Chart for Automotive Service Shops (continued)

*Thisisfor8,000lbs.capacity.Add.65cfmforeach1,000lbs.capacityover8,000

**Thesedevicesareratedbasedupontypical“on-load”performancecharacteristics

Alwayscheckwithtoolmanufacturesforactualconsumptionoftoolsbeingused.Theaboveis

basedonaveragesandshouldnotbeconsideredaccurateforanyparticularmakeoftool

Equipment Air Pressure Range in PSI Compressor cfm Required Per Unit

PortableTools

125-150 Floor Jacks (air powered hydrailic) 6

120-150 Pneumatic Garage Door 3

90-100 Radiator Tester 1

90-100 Spark Plug Cleaner 5

90-100 Spark Plug Tester 0.5

70-100 Transmission and Differential Flusher 3

70-100 **Fender Hammer 9

70-100 **Car Washer 9

70-100 **6” Medium Duty Sander 40


Compressor Selection Chart

Afterlistingalltheairoperateddevicestobesuppliedbytheaircompressor,determine,fromthe

chart,thepressurerangeandvolumeofairrequiredbyeachdevice.Theaircompressormust

maintainaminimumpressureatleastequaltothehighestofthesepressureranges.Forexample,

ifthehighestpressurerangerequiredbyanyonedeviceinagivengroupis120psito150psi,

compressorcuttinginatnotlessthan120psiandcuttingoutat150psishouldberecommended.


Air Consumtion (cfm) Horsepower of

Compressor Pressure (psi) of total equipment Compressor Required

Cut in Cut Out Average Use* Continuous Operation** Two Stage Single Stage

80 100 Up to - 6.6 Up to - 1.9 1/2

80 100 6.7 - 10.5 2.0 - 3.0 3/4

80 100 10.6 - 13.6 3.1 - 3.9 1

80 100 Up to - 14.7 Up to - 4.2 1

80 100 13.7 - 20.3 4.0 - 5.8 1 1/2

80 100 14.8 - 22.4 4.3 - 6.4 1 1/2

80 100 20.4 - 26.6 5.9 - 7.6 2

80 100 22.5 - 30.4 6.5 - 8.7 2

80 100 26.7 - 32.5 7.7 - 10.2 3

80 100 30.6 - 46.2 8.8 - 13.2 3

80 100 32.6 - 38.0 10.3 - 18.0 5

80 100 46.3 - 60.0 13.3 - 20.0 5

80 100 60.1 - 73.0 20.1 - 29.2 7 1/2

80 100 73.1 - 100.0 29.3 - 40.0 10

80 100 100.1 - 150.0 40.1 - 60.0 15

80 100 150.1 - 200.0 60.1 - 80.0 20

80 100 201.0 - 250.0 80.1 - 100.0 25

120 150 Up to - 3.8 Up to - 1.1 1/2

120 150 3.9 - 7.3 1.2 - 2.1 3/4

120 150 7.4 - 10.1 2.2 - 2.9 1

120 150 Up to - 12.6 Up to - 3.6 1

120 150 10.2 - 15.0 3.0 - 4.3 1 1/2

120 150 12.7 - 20.0 3.7 - 5.7 1 1/2

120 150 15.1 - 20.0 4.4 - 5.7 2



Compressor Selection Chart (continued)

*Thesefiguresarenottoberegardedasthecapacityofthecompressorinfreeairoutput,but

instead,arethecombinedfreeairconsumptionofallthetoolstheestablishment,aswellastools

anticipatedforfutureaddedequipment.(Afactorhasbeenintroducedtotakeintoaccount

intermittentoperationoftoolslikelytobeinusesimultaneouslyintheaveragegarageor

industrialplant.

**Thesefiguresaretobeemployedwhenthenatureofthedeviceissuchthatnormaloperation

requiresacontinuoussupplyofcompressedair.Therefore,nofactorforintermittentoperation

hasbeenused,andthefiguresgivenrepresentthecompressorcapacityinfreeairoutput.

**Donotrecommendacompressoroflessthan½Horsepowerifthepneumaticequipment

includesaliftof8,000lbs.capacity.

Air Consumtion (cfm) Horsepower of

Compressor Pressure (psi) of total equipment Compressor Required

Cut in Cut Out Average Use* Continuous Operation** Two Stage Single Stage

120 150 20.1 - 25.9 5.8 - 7.4 2

120 150 26.0 - 39.2 7.5 - 11.2 3

120 150 39.3 - 51.9 11.3 - 17.3 5

120 150 52.0 - 67.5 17.4 - 27.0 7 1/2

120 150 67.6 - 92.5 27.1 - 37.0 10

120 150 92.5 - 140.0 37.1 - 57.0 15

120 150 140.1 - 190.0 57.1 - 77.0 20

120 150 190.1 - 240.0 77.1 - 97.0 25

145 175 Up to - 11.9 Up to - 3.4 1***

145 175 12.0 - 18.5 3.5 - 5.3 1 1/2

145 175 18.6 - 24.2 5.4 - 6.9 2

145 175 24.3 - 36.4 7.0 - 10.4 3

145 175 36.5 - 51.0 10.5 - 17.0 5*

145 175 51.1 - 66.0 17.1 - 26.4 7 1/2

145 175 66.1 - 88.2 26.5 - 35.3 10

145 175 88.3 - 135.0 35.3 - 55.0 15

145 175 135.1 - 185.0 55.1 - 75.0 20

145 175 185.1 - 235.0 75.1 - 95.0 25


Useful Equations

Compressor RPM = Motor Pulley Diameter (inch) x Motor RPM

Compressor Pulley Diameter (inch) )

Motor Pulley Diameter (inch) = Compressor Pulley Diameter (in) x Compressor RPM Motor RPM

Compressor Pulley Diameter (in) = Motor Pulley Diameter (in) x Compressor RPM

Compressor RPM)

Motor RPM = Compressor Pulley Diameter (inch) x Compressor RPM)

Motor Pulley RPM

Pump Up Time (minutes) = Volume (Tank size in Gallons) x Pressure Rise (psi) Pump Delivery (cfm) x PSIA

Volume of Air (cubic feet) Required to Raise Reciever from 0 Gage to Final Pressure

= Volume of Reciever (Cubic Feet)x psig Atomosphereic Pressure (psia)

Piston Speed ( ft )

= 2 x Stroke (inch) x RPM)

min 12

Gallons = Cubic Feet .134

Cubic Feet = .134 x Gallons

Volume (cubic feet) Required Raise Reciever Greater than 0 Gage to a Final Higher Pressure

= Volume of Receiver (Cubic Feet) x Final Pressure (psig) - Initial Pressure (psig)

Atmospheric Pressure (psig)


Helpful Hints/Rules of Thumb

1. Thetypicalbodyshop/garageuses2.5Horsepowerperman

2. 4CFMperHorsepowerona100psiaircompressor

3. Eachpsipressuredropequals0.5%inHorsepower

4. 7.48gallonspercubicfoot

5. TheheatloadonanaircooledcompressorisHPx2545BTU/HR

6. 60%ofcondensateisremovedaftertheaftercooler

7. 96%isremovedaftertherefrigeratedairdryer

8. Pressureandflowareinverselyproportionate

9. Every20degreeincreaseindischargetemperatureincreasesmoisturecontentby50%

How to Size Air Treatment

Therearedifferentclassesofairqualitythataredependentupontheparticlesize,moisture,and

oilcontentintheair.Achartofthedifferentclassesofairandanexampleonhowtodetermine

theISOclasscanbeseenbelow.Whensizingairtreatmentequipment,considerthequalityofair

thecustomerdesires.

Air Quality Class Particle Size (Micron) Pressure Dew Point (°F) Oil Content (PPM)

1 0.1 -94°F 0.01

2 1 -40°F 0.1

3 5 -4°F 1

4 15 -38°F 5

5 40 -45°F 25

6 60 -50°F 40

Example:

• 1MicronParticulate

• 38°FPressureDewPoint(moistureContent)

• 0.1PPMOilConcentration

TheISOClassforthisairqualityis“2-4-2”

Whenselectingadryer,sizefortheworstcasetoinsureproperequipmentperformanceunderall

conditions.Thecriticalvariablestoconsiderwhensizingairtreatmentequipmentare:

• FlowRate(Max) • InletAirPressure(Min)

• InletAirTemperature(Max) • AmbientAirTemperature(MinandMax)

• ProcessWaterTemperature(MinandMax) • Elevation(Max)

• Location(Indoorsvs.Outdoors)


Glossary

Absolute Pressure -Totalpressuremeasuredfromzero.Gaugepressureplusatmospheric

pressure.Forexample,atsealevel,thegaugepressureinpoundspersquareinch(psi)plus14.7

givesabsolutepressureinpoundspersquareinch.

Absolute Temperature -Thechemicalprocessbywhichahygroscopicdesiccant,havingahigh

affinitywithwater,meltsandbecomesaliquidbyabsorbingthecondensedmoisture.

Actual Capacity -Quantityofairorgasactuallycompressedanddeliveredtothedischarge

systematratedspeedandunderratedconditions.Itisusuallyexpressedincubicfeetperminute

(acfm)atcompressorinletconditions.AlsocalledFreeAirDelivered(FAD).

Adsorption -Theprocessbywhichadesiccantwithahighlyporoussurfaceattractsandremoves

themoisturefromcompressedair.Thedesiccantiscapableofbeingregenerated.

Aftercooler -Aheatexchangerusedforcoolingairdischargedfromacompressor.Resulting

condensatemayberemovedbyamoistureseparatorfollowingtheaftercooler.

ASME National Board (U Type) -Anairtankmade,tested,inspected,andregisteredtomeet

standardsofASME.Acertificateissuppliedwitheachtanktoindicatecomplianceandshow

registernumber.TheASMEcertificateisrequiredbylawinmanycitiesandstatestopass

safetycodes.Itassuresthat(1)code-approvedmaterialsareused,(2)thesteelplateiswithout

defectsandisofspecifiedthickness,(3)properweldingtechniquesareemployedbyexperienced

operators,(4)openingsandsupportarethecorrectsize,and(5)thetankhaspassedrigidtests.

ASMEtanksmustbeusedwhereOSHAcomplianceisrequired.

ASME Standard (UM Type) -anairtankmadeandtestedinaccordancewiththeAmerican

SocietyofMechanicalEngineersstandards.ASMEcertificateofcomplianceisfurnishedwith

eachtank.

Atmospheric Pressure -Themeasuredambientpressureforaspecificlocationandaltitude

Automatic Sequencer -Adevicewhichoperatescompressorsinsequenceaccordingtoa

programmedschedule

Booster Compressor -Machineforcompressionairorgasfromaninitialpressurethatisabove

atmospheric


Glossary (continued)

Capacity -Theamountofairflowdeliveredunderspecificconditions,usuallyexpressedincubicfeetperminute(cfm)

Capacity, Actual -Theactualvolumeflowrateofairorgascompressedanddeliveredfromacompressorrunningatits

ratedoperatingconditionsofspeed,pressures,andtemperatures.Actualcapacityisgenerallyexpressedinactualcubicfeet

perminute(acfm)atconditionsprevailingatthecompressorinlet.

Capacity Gauge -Agaugethatmeasuresairflowasapercentageofcapacity,usedinrotaryscrewcompressors

CFM, Free Air -Cubicfeetperminuteofairdeliveredtoacertainpintatacertaincondition,convertedbacktoambient

conditions

CFM, Standard -Flowoffreeairmeasuredandconvertedtoastandardsetofconditionsofpressure,temperatureand

relativehumidity.

Check Valve -Avalvewhichpermitsflowinonlyonedirection

Clearance -Themaximumcylindervolumeontheworkingsideofthepistonminusthedisplacementvolumeperstroke.

Normallyitisexpressedasapercentageofthedisplacementvolume.

Clearance Pocket -Anauxiliaryvolumethatmaybeopenedtotheclearancespace,toincreasetheclearance,usually

temporarily,toreducethevolumetricefficiencyofareciprocatingcompressor

Compressed Air -Airfromatmospherewhichhasbeenreducedinvolume,raisingitspressure.Itthisiscapableof

performingworkwhenitisreleasedandallowedtoexpandtoitsnormalfreestateasitpassesthroughapneumatictoolor

otherdevice.

Compression, Adiabatic -Compressioninwhichnoheattransferredtoorfromthegasduringthecompressionprocess

Compression, Isothermal -Compressioninwhichthetemperatureofthegasremainsconstant

Compression, Polytropic-Compressioninwhichtherelationshipbetweenthepressureandthevolumeisexpressedby

theequationPVnisaconstant

Compression Ratio-Theratiooftheabsolutedischargepressuretotheabsoluteinletpressure

Constant Speed Control-Asysteminwhichthecompressorisfuncontinuouslyandmatchesairsupplytoairdemandby

varyingcompressorload



Cut-In/Cut-OutPressure-Respectively,theminimumandmaximumdischargepressuresat

whichthecompressorwillswitchfromunloadtoloadoperation(cutin)orfromloadtounload

(cutout)

Cycle-Theseriesofstepsthatacompressorwithunloadingperforms;1)fullyloaded,2)

modulating(forcompressorswithmodulatingcontrol),3)unloaded,4)idle

CycleTime-Amountoftimeforacompressortocompleteonecycle

DegreeofIntercooling-thedifferenceinairorgastemperaturebetweentheoutletofthe

intercoolerandtheinletofthecompressor

Deliquescent-Meltingandbecomingaliquidbyabsorbingmoisture

Desiccant-Amaterialhavingalargeproportionofsuracespores,capableofattractingremoving

watervaporfromtheair

DewPoint-Thetemperatureatwhichmoistureintheairwillbegintocondenseiftheairis

cooledatconstantpressure.Atthispointtherelativehumidityis100%

Demand-Flowofairatspecificconditionsrequiredatapointorbytheoverallfacility

Diaphragm-astationaryelementbetweenthestagesofmulti-stagecentrifugalcompressor.It

mayincludeguidevanesfordirectingtheflowingmediumtotheimpellerofthesucceedingstage.

Inconjunctionwithanadjacentdiaphragm,itformsthediffusersurroundingtheimpeller

DischargePressure-AirPressureproducedataparticularpointinthesystemunderspecific

conditions

DischargeTemperature-Thetemperatureatthedischargeflangeofthecompressor.

Displacement-Thevolumesweptoutbythepistonorrotor(s)perunitoftime,normally

expressedincubicfeetperminute\

Efficiency-anyreferencetoefficiencymustbeaccompaniedbyaqualifyingstatementwhich

identifiestheefficiencyunderconsideration,asinthefollowingdefinitionsofefficiency:

Efficiency,Compression-Ratiooftheoreticalpowertopoweractuallyimpartedtotheairorgas

deliveredbythecompressor



Efficiency,Isothermal-Ratioofthetheoreticalwork(ascalculatedonisothermalbasis)tothe

actualworktransferredtoagasduringcompression

Efficiency,Mechanical-Ratioofthepolytropiccompressionenergytransferredtothegas,to

theactualenergytransferredtothegas.

Efficiency,Volumetric-RatioofactualcapacitytopistonDisplacement

Exhauster-Atermsometimesappliedtoacompressorinwhichtheinletpressureislessthan

atmospheric

Filters-Devicesforseparatingandremovingparticulatematter,moistureorentrainedlubricant

fromair

FlangeConnection-Themeansofconnectingacompressorinletordischargeconnectionto

pipingbymeansofboltedrims(flanges)

FreeAir-Airatatmosphericconditionsatanyspecifiedlocation,unaffectedbythecompressor

Full-Load-Aircompressoroperationatfullspeedwithafullyopeninletanddischargedelivering

maximumairflow

Gas-Oneofthethreebasicphasesofmatterwhileairisagas,inpneumaticsthetermgas

normallyisappliedtogasesotherthanair

GaugePressure-Thepressuredeterminedbymostinstrumentsandgauges,usuallyexpressedin

psig.Barometricpressuremustbeconsideredtoobtaintrueorabsolutepressure

Horsepower,Brake-Horsepowerdeliveredtotheoutputshaftofamotororengine,orthe

horsepowerrequiredatthecompressorshafttoperformwork.

Horsepower,TheoreticalorIdeal-Thehorsepowerrequiredtoisothermallycompresstheairor

gasdeliveredbythecompressoratspecifiedconditions

Humidity,Relative-Therelativehumidityofagas(orair)vapormixtureistheratioofthe

partialpressureofthevaportothevaporsaturationpressureatthedrybulbtemperatureofthe

mixture.



IndicatedPower-Powerascalculatedfromcompressor-indicateddiagrams

IndicatorCard-Apressure-volumediagramforacompressororenginecylinder,producedby

directmeasurementbyadevicecalledanindicator.

InletPressure-theactualpressureattheinletflangeofthecompressor

Intercooling-Theremovalofheatformairorgasbetweencompressorstages

Intercooling,degreeof-thedifferenceinairorgastemperaturesbetweentheinletofthe

compressorandtheoutletoftheintercooler

Intercooling,Perfect-Whenthetemperatureoftheairorgasleavingtheintercoolerisequalto

thetemperatureoftheairorgasenteringtheinletofthecompressor

Leak-Anunintendedlossofcompressedairtoambientconditions

Loadtime-Timeperiodfromwhenacompressorloadsuntilitunloads

Load/UnloadControl-Controlmethodthatallowsthecompressortorunatfull-loadoratno

loadwhilethedriverremainsataconstantspeed

ModulatingControl-Systemwhichadaptstovaryingdemandbythrottlingthecompressorinlet

proportionallytothedemand

Multi-Stagecompressors-Compressorshavingtwoormorestageoperatinginseries

PerformanceCurve-Usuallyaplotofdischargepressureversusinletcapacityandshaft

horsepowerversusinletcapacity

PistonDisplacement-Thevolumesweptbythepiston;formultistagecompressors,thepiston

displacementofthefirststageistheoverallpistondisplacementoftheentireunit

PneumaticTools-Toolsthatoperatebyairpressure

PositiveDisplacementCompressors-Compressorsinwhichsuccessivevolumesofairorgas

areconfinedwithinaclosedspaceandthespacemechanicallyreduced,resultingincompression.

Thesemaybereciprocatingorrotating



Pressure-Forceperunitarea,measuredinpoundspersquareinch(psi)

PressureDewPoint-Foragivenpressure,thetemperatureatwhichwaterwillbegintocondenseoutofair

PressureDrop-Lossofpressureinacompressedairsystemorcomponentduetofrictionorrestriction

PressureRange-Differencebetweenminimumandmaximumpressuresforanaircompressor.Alsocalledcutin/cutout

orload/no-loadpressurerange.

PressureRise-thedifferencebetweendischargepressureandintakepressure

Pressure,static-thepressuremeasuredinaflowingstreaminsuchamannerthatthevelocityofthestreamhasnoeffect

onthemeasurement

RatedCapacity-Volumerateofairflowatratedpressureataspecificpoint

RatedPressure-Theoperatingpressureatwhichcompressorperformanceismeasured

Receiver-Avesselortankusedforstorageofgasunderpressure.Inalargecompressedairsystemtheremaybeprimary

andsecondaryreceivers

ReciprocatingCompressor-Compressorinwhichthecompressingelementisapistonhavingareciprocatingmotionina

cylinder

RelativeHumidity-Theratioofthepartialpressureofavaportothevaporsaturationpressureatthedrybulb

Rotor-Therotatingelementofacompressor.Inadynamiccompressor,itiscomposedoftheimpeller(s)andshaft,andmay

includeshaftsleevesandathrustbalancingdevice

Seals-Devicesusedtoseparateandminimizeleakagebetweenareasofunequalpressure

Sequence-Theorderinwhichcompressorsarebroughtonline

Shaft-Thepartbywhichenergyistransmittedfromtheprimemoverthroughtheelementsmountedonit,totheairorgas

beingcompressed

SolePlate-Apad,usuallymetallicandembeddedinconcrete,onwhichthecompressoranddriveraremounted

SpecificPower-Ameasureofaircompressorefficiency,usuallyintheformofbhp/100acfm



SpecificWeight-Weightofairorgasperunitvolume

Speed-Thespeedofacompressorreferstothenumberofrevolutionsperminuteofthe

compressordriveshaftorrotorshaft

Stages-aseriesofstepsinthecompressionofairoragas

StandardAir-theCompressedAirandGasInstituteandPNEUROPhaveadoptedthedefinition

usedinISOstandards.Thisisairat14.5psia(1bar);68°F(20°C)anddry(0%relative

humidity).

Start/StopControl-Asysteminwhichairsupplyismatchedtodemandbythestartingand

stoppingoftheunit

Torque-Atorsionalmomentorcouple.Thistermtypicallyreferstothedrivingcoupleofa

machineormotor

VacuumPumps-Compressorswhichoperatewithanintakepressurebelowatmospheric

pressureandwhichdischargetoatmosphericpressureorslightlyhigher.

Valves-Deviceswithpassagesfordirectingflowintoalternatepathsortopreventflow

WaterCooledCompressor-Compressorcooledbywatercirculatedthroughjacketssurrounding

cylindersorcasingsand/orheatexchangersbetweenandafterstages.

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