壓縮機(jī)中英文翻譯、外文文獻(xiàn)翻譯、外文翻譯

CompressorsThemaindifferencebetweenpumpsandcompressorsisthatthefluiddeliveredbycompressors--air--iscompressedandunderpressureatthetimeitisdelivered,evenifthereisnoloadonthesystem.Mostdevicesusedtocompressairareverysimilarinconceptand--perhapseveninhardware--tohydraulicpumps,andselectionconsiderationsaresimilar.Theonlyothersubstantivedifferenceisthatmosthydraulicsystemsarepoweredbyasinglepumpthatisactuallyapartofthesystem,whereasahostofpneumaticsystemsareoftenpoweredbyasinglecompressor,whichisalmosta"utility"intheplantlikewaterorelectricservice.Nevertheless,manysmallcompressorsareavailableforspecific,discretejobs;typicallytheyarepositive-displacementcompressors.Dynamic,ornonpositive-displacementcompressorsaretypicallylarger,facility-typeunits.Compressorsarefairlysimpledevices,capableoflongperiodsofmaintenance-freeoperationifproperlyintegratedintopneumaticsystems.Yettimeandagaintheysufferfromearlyfailuresbecauseobviousprecautionswereignoredduringsystemdesign.Fourbasicrulescanprovidesubstantialimprovementincompressorlifewithonlymoderatedesigneffort:? Pumpsandcompressorsshouldbesizedtoprovideatleasttherequiredpressureandflow,andpreferably10to25%more.? Filtersshouldbeselectedtoprotectthepumpingunit,andsometimestoprotectdownstreamcomponentsorproductsaswell.? Reliefvalvesshouldbeselectedtokeeppressureorvacuumatappropriatelevels.? Pumpingunitsshouldbeplacedinaclean,cool,dryenvironment.Bellowscompressorsconsistofaweldedmetalbellowsconnectedtoinletandoutletportswithcheckvalves.Thesecompressorstypicallycoverthepressurerangeupto10psig,andareusedinpollutiondetectingandmeasuringdevices,gas-samplinginstruments,andmedicalapplications.Lubricationisnotneeded,allowinghighpuritiestobemaintained.Vanecompressorsaresimplemachineswithfewmovingparts.Liketheirhydrauliccounterparts,vanepumps,thecompressorsareinexpensive,withlowoperatingcost,andlowstarting-torquerequirement.Theyarecompactandrelativelyvibrationfree,withlittlepulsationinthecompressoroutput.Theslidingvanesarecloselyfittedintherotorslotsandwearverylittleduringoperation.Thesecompressorsareavailableinpowerrangesfrom10to500hp,atpressuresto150psi.Reciprocatingcompressorsconsistofapistonmovingwithinthecylindertotrapandcompressthegas.Inprinciple,suchaunitislikeanautomobileengine,withthepistonscompressingthegasandvalvescontrollingitsinletandoutflows.Sizesrangefromlessthan1toover5,000hp.Reciprocatingcompressorshavegoodpartloadefficienciesandareusefulforwidevariationsinoperatingconditions.Diaphragmcompressorsareamodificationofthereciprocatingcompressor.Compressionisperformedbytheflexingofametalorfabricateddiaphragmwhichiscausedbythemotionofareciprocatingpistoninacylinderunderthediaphragm.Thespacebetweenthediaphragmandthepistonisusuallyfilledwithliquid.Lobed-rotorcompressorshavetworotatingelementsthatrevolveinoppositedirectionsinachamber.Inmostcompressors,therotorsdonotactuallytouchanddonotdriveeachother,beingdriveninsteadbytiminggears.Becausetherotorsdonotactuallytouch,airleaksbetweenthematasmallbutconstantrate.Thisleakage,called"slip,"isconstantforagivencompressoratagivenpressure.Forhighestefficiency,thesecompressorsshouldbeoperatedatmaximumspeed.Theyareavailableinpowerrangesfrom7to3,000hp,deliveringpressuresto250psi.Becausetheinternallobesdonotcontact,theyneednolubrication.Liquidpistoncompressorshavenomovingpartsinwearingcontact.Arotorwithmultipleforward-curvedbladesrotatesinanellipticalcasing.Fluid,trappedwithinthecasing,iscarriedaroundtheinnerperipherybytheblades.Spacebetweenthebladeschangesvolumeduetotheellipticalfluidpath,andtheinnersurfaceoftheliquidringtrappedbetweenthebladesservesasthefaceofaliquidpiston.Thesecompressorsacceptliquidslugsandfineparticleswithoutseriousdamage.Lubricationisrequiredonlyinbearingslocatedoutsidethepumphousing.Thesecompressorsdeliverupto150psithroughouttherangeof10to500hp.Centrifugalcompressorsarebestsuitedtomovinglargevolumesofairatrelativelylowpressures.Basically,theyconsistofahigh-speedrotatingimpeller,adiffusersectionwherevelocityisreducedandpressureincreased,andacollectorsectionthatfurtherreducesvelocityandincreasespressure.Centrifugalcompressorscanhandlehighflowdemandswell,butwhendemanddecreasesmuchbelowratedflowandoutputpressurerises,thecompressorscansurge.Insurge,thepressurefieldatthecompressoroutletvariesrandomly.Ifallowedtocontinue,thisconditioncandamagebearings,blades,andeventhehousingitself.Centrifugalcompressorstypicallyusefromtwotosixstages,supplyingfrom400to3,000cfmatspeedsto20,000rpm.Regenerativeblowers(alsoknownasperipheralblowers)useadisclikeimpellerwithbladesmountedarounditsoutsideedge.Astheimpellerrevolves,airisdrawnintothespacebetweentheblades.Centrifugalforcemovestheairinaspiralpathoutwardtothehousing,whereitslipsbytheinitialbladeandreturnstothebaseofthesucceedingblade,wheretheprocessisrepeated.Insomemodels,aflowsplittercreatestwoflowpaths,sothattheairmustmaketwocircuitsaroundtheimpeller.Inothermodels,thesplitterisomitted,andtheairmakesonlyonecircuitbeforeexiting.Regenerativeblowersprovideairflowsupto1,000cfmandpressuresto8psi.Helicalcompressorslookliketwogiantscrewsmeshingtogether;theyworkmuchlikehydraulicscrewpumps.Maximumpressurefromthesemachinesisapproximately125psiinsingle-stageconfigurations.Helicalcompressorsmaybeeitheroilfloodedordry.Dryhelicalcompressors,likelobedunits,requiretiminggearstomaintainproperclearancebetweentherotatingelements.Theseunitsaremostefficientlyoperatedathighcontinuousspeeds.Floodedcompressorsdonotrequireanytiminggears,becausetheoil-ladenscrewsurfacescandriveeachother.However,oilseparatorsareneededtoremovetheoilfromtheairasitleavesthecompressor.Theyareavailableoverapowerrangeofabout7to300hp.Single-screwcompressorsarebasedonthesameprincipleashelicalcompressors.Asthecentralscrewrotates,airtrappedbetweenthescrewteethiscompressedagainstthestar-shapedrotors.Thesecompressorstendtohavelowvibrationandnoiselevels,andlowdischargepressures.Lubricationisrequired.PumpsvacuumpumpsInprinciple,industrialvacuumpumpsaremerelycompressorsrunwiththeinletattachedtothevacuumsystemandtheoutletopentoexhaust.Insmallersizes,compressorsandvacuumpumpsareoftenidenticalmachines.However,inthelargesizesthatmightpoweraplant-widevacuumsystem,themachinesdifferinminorwaysthatareintendedtoenhanceefficiencyforoneapplicationortheother.Manufacturersstronglyadvisethatthesamemachinenotbeusedforbothvacuumandcompressionatthesametime.Theheavyloadswilldamageit.Threecriteriacontrolpumpselection:degreeofvacuumproduced,rateofairremoval,andpowerrequirement.However,applicationssuchasfiltrationmaysubjecttheunittotheingestionofforeignmaterial.Thefirstpumpperformancecriterionisthevacuumitproduces.ManufacturersprovideamaximumvacuumratingexpressedasabsolutepressureinmmHg,orvacuuminin.Hg.Largerunitsareusuallyratedonlyforcontinuousduty,butsmallerunitsmayhaveahighervacuumratingforintermittentduty.Insmallerunits,temperature-riseconsiderationslimitthevacuumthatcanbeproduced.Continuousandintermittentvacuumratingsaredeterminedforstandardatmosphericpressure:29.92-in.Hg.Lowerambientpressuresreducethevacuumthatcanbeproduced.Theratingisdeterminedfrom:whereVa=adjustedvacuumrating,in.Hg;Vo=originalvacuumratingatstandardconditions,in.Hg;andPa=anticipatedatmosphericpressureattheapplicationsite,in.Hg.Rateofairremovalisthesecondcriterion.Vacuumpumpsareflowratedaccordingtothevolumeofairexhaustedwithnopressuredifferentialacrossthepump.Manufacturersprovidecurvesshowingfreeairdeliveryatratedspeedforvacuumlevelsrangingfrom0-in.Hg(so-called"opencapacity")tomaximumvacuumrating.Somemanufacturersalsoprovidecurvesofcapacityatdifferentspeedsforagivenvacuum.Thelastpumpcriterionispowerrequirement.Comparedwithaircompressors,vacuumpumpsrequirerelativelylittlepower.Atlowflows,vacuum(orpressuredifferential)ishigh;athighflows,vacuumislow.Therefore,power,whichisproportionaltoflowandpressuredifferential,isgenerallylow.Poweroutputofthepumpcanbefoundfrompressure-flowcurvesprovidedbymanufacturers.Inputpowerandspeedrequirementsarealsoshowninthedata.Overallpumpefficiency(includingbothvolumetricandmechanicalefficiency)canbeevaluatedbycombiningthisdata.Thisisdonebydividingthefree-aircapacityofthepumpattherequiredvacuumlevelbydrivepowerrequiredatthatcondition.Theresultisproportionaltotheproductofgagevacuumandair-flowrateandisrepresentativeofefficiency.Allthreeperformancecriteria--vacuum,flowandpower--canbeaffectedbypumptemperature.Athighervacuumlevels,littleairflowsthroughthepump,solittleheatistransferredtotheair.Muchoftheheatgeneratedbyfrictionmustbedissipatedbythepump.Thisheatgraduallyraisespumptemperatureandcandrasticallyreduceservicelife.Temperatureexcursionsareespeciallyimportanttointermittent-dutypump,whichcanoverheatifontimegreatlyexceedsofftime.Vacuumpumpsareclassifiedaseitherpositiveornonpositivedisplacement.Apositive-displacementpumpcreatesvacuumbyisolatingandcompressingadistinct,constantvolumeofair.Thecompressedairisventedoutoneport,andavacuumiscreatedattheotherportwheretheairisdrawnin.Thisgeneratesrelativelyhighvacuum,butlittleflow.Anonpositive-displacementpump,ontheotherhand,usesrotatingimpellerbladestoaccelerateairandcreateavacuumattheinletport.Whilenonpositive-displacementpumpscannotproducehighlevelsofvacuum,theyprovidehighflowrates.Principaltypesofpositive-displacementvacuumpumpsincludepiston,diaphragm,rocking-piston,rotary-vane,lobed-rotor,rotary-screw,andliquid-ringdesigns.Reciprocating-pistonpumpsgeneraterelativelyhighvacuums--from27tomorethan29in.Hg--underavarietyofoperatingconditions.Typicalpumpsofthistypehaveoneormorepistonslinkedtoarotatingcrankshaft.Thealternatingpistonactionmovesairpastcheckvalvesinthecylinderheadtocreateavacuumattheinletport.Lubricatedpistonpumpsarequieter,producelessvibration,haveahighercapacity,andfeatureamuchlongerlifethanoillessdesigns,buttheyarealsoheavierandmoreexpensive.Diaphragmpumpsoffertheadvantageofthefluidchamberbeingtotallysealedfromthepumpingmechanisms.Aneccentricconnectingrodmechanicallyflexesadiaphragminsidetheclosedchambertocreateavacuum.Thisresultsinsomewhatlowervacuumcomparedtothatproducedbyareciprocatingpiston.However,thediaphragm'slowercompressionratio--lowflow,largediameter,andshortstroke--makesforquiet,economical,andreliableoperation.Thedesignisavailableinbothoneandtwo-stageversions.Single-stagepumpsprovidevacuumupto25.5in.Hg,whiletwo-stageunitsareratedto29in.Hg.Rocking-pistonpumpscombinethecompactsizeandquiet,oillessoperationofthediaphragmpumpwiththehigh-vacuumcapabilitiesofthereciprocating-pistonpump.Here,apistonisrigidlymounted(nowristpin)ontopofthediaphragmunit'seccentricconnectingrod.Anelastomericcupskirtsthepistonandfunctionsbothasaseal--equivalenttotheringsonapistoncompressor--andasaguidememberfortherod.Thecupexpandsasthepistontravelsupward,thusmaintainingcontactwiththecylinderwallsandcompensatingfortherockingmotion.Theabsenceofawristpinisthekeytothepump'slightweightandcompactsize.Single-stagerocking-pistonpumpsproducevacuumto27.5in.Hg;two-stagedesignscangenerate29in.Hgormoreofvacuum.Rocking-pistonpumpsarealsorelativelyquiet,operatingatsoundlevelsaslowas50dBA.Adrawbacktorocking-pistonpumpsisthattheycannotgeneratealotofairflow.Eventhelargesttwin-cylindermodelshaveflowratesoflessthan10cfm.Rotary-vanepumpsuseaseriesofsliding,flatvanesrotatinginacylindricalcasetogeneratevacuum.Asaneccentricallymountedrotorturns,thevanesslideinandout,trappingaquantityofairandmovingitfromtheinletsideofthepumptotheoutlet.Rotary-vanepumpsusuallyhavelowervacuumratingsthanpistonpumps,inthe20to28in.Hgrange.However,thereareafewexceptions.Sometwo-stage,oil-lubricateddesignshavevacuumcapabilitiesupto29.5in.Hg.Pumpswithrecirculatingoilsystemsreachstillhighervacuums,inthelessthan1-torrrange.Thepumpsofferanumberofadvantages,includinghighflowcapacities,lowstartingandrunningtorquerequirements,vibration-freeoperation,andcontinuousairflow.Novalvesrestrictfloworrequiremaintenanceintherotarydesign.Thecompactunitsarealsoquiet,generatingaslittleas45dBAorsound.Dependingontheapplicationandvacuumlevelrequired,aneconomicalalternativetousingahigh-vacuumpumpistwostandard,stagedrotary-vanepumps.Or,ahigh-volume,low-dutypumpratedforcontinuousdutyof20in.Hgsometimescanbeoperatedatrestrictedairflowor"blanked-off"conditionsforshortperiodsoftimetoprovidehighervacuums.Aswithothertypesofpumpsavailableinbothlubricatedandoillessconfigurations,lubricatedrotary-vanepumpsarecapableofslightlyhighervacuumcomparedtooillessdesigns.Liquid-ringpumpsfeatureamultibladeimpeller,mountedeccentricallyinacylindricalcasethatispartlyfilledwithwater.Astheimpellerrotates,liquidisthrownoutwardbycentrifugalforcetoformaliquidringconcentricwiththeperipheryofthecasing.Duetotheeccentricpositionoftheimpeller,theairspaceintheimpellercellexpandsduringthefirst180°ofrotation,creatingavacuum.Duringthenext180°ofrotation,theairspaceisreduced,dischargingcompressedairandwater.Inadditiontobeingthecompressionmedium,theliquidringabsorbstheheatofcompressionaswellasanypowderorliquidslugsentrainedintheair.Rotary-screwandlobed-rotorvacuumpumpsaretwoothertypesofpositivedisplacementpumps.Neitherlubricateddesignisaswidelyusedasrotary-vaneandpistonpumps,especiallyinsmallersizes.Duetothesizeofthegearsandrotors,bothdesignslendthemselvestolargerinstallations.Arotary-screwpump'svacuumcapabilitiesaresimilartothoseofpistonpumps,withtheaddedadvantageofbeingnearlypulse-free.Twomeshingrotorswithhelicalcontourstrapairasthescrewsturninoppositedirections.Thisactioncreateschambersofdecreasingvolumebehindandincreasingvolumeinfrontoftherotorchambers.Lobed-rotorpumpsbridgethegapbetweenpositiveandnonpositive-displacementunits.Thepumpshaveapairofmatinglobedimpellersthatrotateinoppositedirections,trappingairandwithdrawingitfromthesystem.High-speed,multistagedcentrifugalblowersandregenerativeblowersarethemajortypesofnonpositive-displacementpumps,generallyoperatingathighspeedsandattainingmoderatevacuumlevels.Centrifugalblowers,forexample,areanexcellentchoicewhereonlyintermittentuseisrequired.Tokeepcostsdown,ashort-lifebrush-typeacordcmotorpowerstheseblowers,whicharewidelyusedinvacuumcleaners.Regenerativeblowershavemanyadvantagesbecauseindividualairmoleculespassthroughmanycompressioncycleswitheachrevolutioncomparedtothesinglecompressionperstageformultistagedcentrifugaltypes.Atfirstglance,regenerativeblowersaresimilartorotary-vanepumps,buthaveaspecialbladeandhousingconfiguration.Astheimpellerrotates,centrifugalforcemovestheairmoleculesfromthebladeroottoitstip.Leavingthebladetip,theairflowsaroundthehousingcontourandbackdowntotherootofasucceedingblade,wheretheflowpatternisrepeated.Thisactionprovidesaquasi-stagingeffecttoincreasepressuredifferentialcapability.Thespeedoftherotatingimpellerdeterminesthedegreeofpressurechange.Theendresultisnotaparticularlyhighvacuum--approximately100-in.H2Oinsingle-stagemodels.Butflowcapacityisveryhigh,uptoseveralhundredcfm.Multistageversionsproducehighervacuumlevels,butatlowerflowrates.壓縮機(jī)泵和壓縮機(jī)主要區(qū)別是：流體被壓縮機(jī)傳送—?dú)怏w—在它被傳送的同時(shí)被壓縮并處于壓力之下，即使系統(tǒng)在沒有載荷的情況下。大多數(shù)用于空氣壓縮的裝置原理上非常相似--甚至在零部件上-如液壓泵，考慮和選擇是相同的。它們本質(zhì)上唯一的不同是大多數(shù)的液壓系統(tǒng)由單一泵供給能量，并且泵實(shí)際上是系統(tǒng)的一部分，而大多數(shù)的氣動(dòng)動(dòng)力系統(tǒng)往往由單一壓縮機(jī)供給能量，像廠區(qū)內(nèi)的水、電力服務(wù)一樣它幾乎是廠區(qū)“公共設(shè)施”。不過有許多小型壓縮機(jī)用于特殊、不連續(xù)的工作場合。他們通常是可移動(dòng)型壓縮機(jī)。動(dòng)力型的或非移動(dòng)型壓縮機(jī)通常是大型的單元設(shè)備。壓縮機(jī)裝置比較簡單，如果納入適當(dāng)?shù)臍鈩?dòng)系統(tǒng)則使壓縮機(jī)能長期維持運(yùn)轉(zhuǎn)，由于在系統(tǒng)設(shè)計(jì)中忽視了明顯的注意事項(xiàng)導(dǎo)致了壓縮機(jī)一次又一次的前期故障。只要適度的努力遵循四項(xiàng)基本規(guī)則可大大提高壓縮機(jī)設(shè)計(jì)壽命：泵和壓縮機(jī)應(yīng)該以最低壓力和流量來分級，最好在10至25%以上；應(yīng)選擇過濾器來保護(hù)泵單元，并且有時(shí)也保護(hù)下游產(chǎn)品和部件；應(yīng)選擇安全閥來保持壓力或真空度在適當(dāng)?shù)乃?；泵單元?yīng)安放在一個(gè)干凈、通風(fēng)、干燥的環(huán)境。波紋管式壓縮機(jī)：包括金屬焊接波紋管，由截止閥連接在進(jìn)、出端口。這種壓縮機(jī)主要用于各種壓力高達(dá)10磅/平方英寸左右，用于污染檢測和測量儀器、氣體取樣工具、醫(yī)療設(shè)備。不需要注潤滑油，因而使其保持在較高的純凈度。葉輪式壓縮機(jī)：由一些簡單的轉(zhuǎn)動(dòng)零件構(gòu)成。相對于它們水力的相似物-葉輪泵-來說，壓縮機(jī)價(jià)格便宜,操作成本低和低的開車需求。它們結(jié)構(gòu)緊湊，并且在壓縮機(jī)輸出時(shí)相關(guān)的自由顫動(dòng)、壓力波動(dòng)小。滑動(dòng)的葉輪在轉(zhuǎn)子溝槽中緊密配合并且在操作時(shí)很少磨損。這些壓縮機(jī)可用在動(dòng)力范圍在10至500惠普，壓力為150磅/平方英寸。往復(fù)式壓縮機(jī)：由一個(gè)活塞在汽缸內(nèi)移動(dòng)而吸入并壓縮氣體。原則上，像汽車發(fā)動(dòng)機(jī)一樣的單元由活塞壓縮氣體并且有控制閥控制氣體的吸入與流出。尺寸范圍規(guī)模小于1個(gè)調(diào)和級數(shù)到5000惠普。往復(fù)式壓縮機(jī)具有良好的部分負(fù)載效率可廣泛用于各種操作條件。隔膜式壓縮機(jī)：是一種正在改進(jìn)的往復(fù)式壓縮機(jī)。壓縮是由一片有彈性的金屬或預(yù)制的隔膜它的運(yùn)動(dòng)由在隔膜子下的氣缸中的往復(fù)運(yùn)動(dòng)的活塞所引起的。隔膜與活塞之間的空間通常充滿液體。葉片-轉(zhuǎn)子式壓縮機(jī)：有兩個(gè)旋轉(zhuǎn)元件它們在工作腔中以相反地方向進(jìn)行旋轉(zhuǎn)。在大多數(shù)壓縮機(jī)中轉(zhuǎn)子實(shí)際上并不相互接觸而且并不相互驅(qū)動(dòng),而是由驅(qū)動(dòng)齒輪來間接傳動(dòng)。因?yàn)闆]有實(shí)際相互接觸它們之間的空氣泄漏率很小而且保持恒定。這個(gè)泄漏量，被稱為“錯(cuò)漏”因?yàn)槟骋惶囟▔嚎s機(jī)有一個(gè)特定的壓力。為了保持高效率，壓縮機(jī)應(yīng)該以最高轉(zhuǎn)速運(yùn)轉(zhuǎn)。他們可利用在動(dòng)力范圍為7至3000惠普，傳送壓力達(dá)到250磅/平方英寸。由于內(nèi)部葉片沒有相互接觸，它們不需要注潤滑油。流體活塞壓縮機(jī)：沒有移動(dòng)部件處于磨損接觸。一個(gè)帶多片向前彎曲葉片的轉(zhuǎn)子在橢圓形外殼中旋轉(zhuǎn)。流體被截留在殼體隨著葉片的旋轉(zhuǎn)被帶到內(nèi)部殼體的邊緣。葉片之間的空間隨著橢圓形通道的改變而改變，并且被截留在葉片之間的液環(huán)的內(nèi)表面被看作流體活塞的表面。這些壓縮機(jī)可以承受液滴和好的微粒而不產(chǎn)生嚴(yán)重的破壞。潤滑油只須注在泵機(jī)架外的軸承上。這種壓縮機(jī)可傳送壓力高達(dá)150磅/平方英寸動(dòng)力范圍為10至500惠普。離心式壓縮機(jī)：最適合運(yùn)送大容量壓力較低的空氣?；旧?，他們包括高速旋轉(zhuǎn)葉輪,一個(gè)擴(kuò)散節(jié)，在擴(kuò)散節(jié)中流動(dòng)速度降低但壓力增高,還有一個(gè)收集部件，在其內(nèi)部進(jìn)一步降低速度，增高壓力。離心式壓縮機(jī)可處理高流量需求的井道，但是當(dāng)需求量大大低于額定流量和壓力升高，壓縮機(jī)將產(chǎn)生喘振。如果產(chǎn)生喘振壓縮機(jī)出口的壓力范圍將產(chǎn)生隨意的改變。如果任其繼續(xù)下去，這種情況會破壞軸承、葉片，甚至自己的機(jī)架。離心壓縮機(jī)通常使用二至六級，可供應(yīng)量為400至3000立方英尺/秒，轉(zhuǎn)速可達(dá)20,000轉(zhuǎn)/分。再生式鼓風(fēng)機(jī)（又名環(huán)形滑道式鼓風(fēng)機(jī)）：采用了邊緣外安裝了葉片的推動(dòng)葉輪。由于這個(gè)旋轉(zhuǎn)推動(dòng)葉輪，空氣被吸入葉片之間的空間。離心力使空氣呈螺旋形路線離開葉輪室，空氣由初始的葉片泄漏并返回低一級的葉片，在這一級這個(gè)過程被重復(fù)。有些型號一個(gè)流程被分離成兩個(gè)流程途徑,因此使空氣沿推動(dòng)葉輪要做兩次循環(huán)。其它型號，分離被省略了，因此空氣在離開時(shí)只做一次循環(huán)，再生式鼓風(fēng)機(jī)提供空氣流速多達(dá)1000立方英尺/秒和壓力達(dá)8磅/平方英寸。螺旋式壓縮機(jī)：像兩根巨大的螺桿嚙合在一起；它們的操作很像液壓螺桿泵。這些壓縮機(jī)的單級結(jié)構(gòu)最大壓力大約為125磅/平方英寸。螺旋式壓縮機(jī)可以是有油潤滑也可以是無有潤滑。無油潤滑螺旋式壓縮機(jī)：像葉片式單元一樣，需要傳動(dòng)齒輪使旋轉(zhuǎn)元件保持適當(dāng)?shù)那鍧崱＿@些單元在高速連續(xù)不斷的操作中的效率非常高。有油潤滑式壓縮機(jī)：不需要任何調(diào)整齒輪，因?yàn)槁輻U表面的石油可以帶動(dòng)對方相互驅(qū)動(dòng)。不過當(dāng)石油離開壓縮機(jī)時(shí)，需要用石油分離器從空氣中分離出石油。他們有較廣泛使用的動(dòng)力范圍約為7至300惠普。單螺桿式壓縮機(jī)：與螺旋式壓縮機(jī)基于同樣的原則。由于主螺桿旋轉(zhuǎn)截留在螺桿旋齒中的空氣沿著與星型回轉(zhuǎn)體相反的方向壓縮。這些壓縮機(jī)趨于低振動(dòng)、低噪音、低排放壓力.需要注潤滑油。泵真空泵原則上，工業(yè)真空泵與壓縮機(jī)類似，只是它的入口連接在真空系統(tǒng)而出口直接排入大氣，在小型號中，壓縮機(jī)與真空泵往往是相似的機(jī)器。不過，在大型號中它們?yōu)槌商椎恼婵障到y(tǒng)提供能量、在中型真空泵方面有所不同它一方面為了提高效率或有其它用途。廠商強(qiáng)烈呼吁在同一機(jī)器不能在同一時(shí)間同時(shí)進(jìn)行抽真空和壓縮。沉重的負(fù)載將會破壞真空泵。三個(gè)標(biāo)準(zhǔn)來控制泵的選擇:抽真空程度，空氣采集量和電力需求。不過，由于過濾系統(tǒng)的應(yīng)用受到對等過濾外來物質(zhì)的影響。泵性能的第一標(biāo)準(zhǔn)是它所產(chǎn)生的真空度。廠商所提供的最高真空度用毫米汞柱或英寸汞柱絕對壓力表示。通常大的單元只用連續(xù)負(fù)載評定、但是小單元可以用較高的真空度為間歇性負(fù)載。在小單元中由于要考慮溫度上升補(bǔ)償因此限制了泵所能產(chǎn)生的真空度。持續(xù)或間歇真空度值為標(biāo)準(zhǔn)大氣壓所確定為:29.92英寸汞柱。較低的環(huán)境溫度壓力將降低泵所能產(chǎn)生的真空度值，數(shù)值由下式所確定：

而Va=調(diào)整真空度值，英寸汞柱；Vo=標(biāo)準(zhǔn)條件下的原始真空度數(shù)值，英寸汞柱；Pa=當(dāng)?shù)卮髿鈮簲?shù)值，英寸汞柱。第二標(biāo)準(zhǔn)是輸送空氣值。真空泵額定流量是根據(jù)通過泵的沒有壓力差的排出空氣量所決定的。廠商提供的在標(biāo)準(zhǔn)傳送速度下的自由空氣的真空度級別的顯示曲線范圍從0英寸汞柱（所謂“開放容量”）到最大真空度值。一些廠家還提供某一給定真空度的不同速度得容量曲線。最后一個(gè)泵的標(biāo)準(zhǔn)是功率需求。與空氣壓縮機(jī)相比，真空泵需要較少的功率。在低流量、高真空度（或壓差）；在高流量、真空度也是低的。因此，功率-它是流量與壓差之間的比例關(guān)系，因此它通常也偏低。泵的輸出功率可以由廠商提供的壓力-流量曲線圖中查得。輸入功率和需求的速度也顯示這些數(shù)據(jù)中。因此全部泵的效率（包括容積效率和機(jī)械效率）可用這些相關(guān)的數(shù)據(jù)進(jìn)行評價(jià)。這一點(diǎn)在劃分泵的自由空氣容量所需開車功率時(shí)所必須的真空度級別時(shí)被完成的。除以自由空氣的能力水平的真空泵的驅(qū)動(dòng)力所需的必要條件。其