气压系统中英文对照外文翻译文献

PAGE中英文对照外文翻译文献(文档含英文原文和中文翻译)PneumaticsystemandvariousvalvebasicintroductionPneumaticsystemsusepressurizedgasestotransmitandcontrolpower.Asthenameimplies,pneumaticsystemtypicallyuseair(ratherthansomeothergas)asthefluidmediumbecauseairisasafe,low-cost,andreadilyavailablefluid.Itisparticularlysafeinenvironmentswhereanelectricalsparkcouldigniteleaksfromsystemcomponents.Inpneumaticsystems,compressorsareusedtocompressandsupplythenecessaryquantitiesofair.Compressorsaretypicallyofthepiston,vaneorscrewtype.Basicallyacompressorincreasesthepressureofagasbyreducingitsvolumeasdescribedbytheperfectgaslaws.Pneumaticsystemsnormallyusealargecentralizedaircompressorwhichisconsideredtobeaninfiniteairsourcesimilartoanelectricalsystemwhereyoumerelyplugintoanelectricaloutletforelectricity.Inthisway,pressurizedaircanbepipedfromonesourcetovariouslocationsthroughoutanentireindustrialplant.Thecompressedairispipedtoeachcircuitthroughanairfiltertoremovecontaminantswhichmightharmthecloselyfittingpartsofpneumaticcomponentsuchasvalvesandcylinders.Theairthenflowsthroughapressureregulatorwhichreducesthepressuretothedesiredlevelfortheparticularcircuitapplication.Becauseairisnotagoodlubricant(containsabout20%oxygen),pneumaticssystemsrequiredalubricatortoinjectaveryfinemistofoiltheairdischargingfromthepressureregulator.Thispreventswearofthecloselyfittingmovingpartsofpneumaticcomponents.Freeairfromtheatmospherecontainsvaryingamountsofmoisture.Thismoisturecanbeharmfulinthanitcanwashawaylubricantsandthuscauseexcessivewearandcorrosion.Hence,incomeapplications,airdriersareneededtoremovethisundesirablemoisture.Sincepneumaticsystemsexhaustdirectlyintotheatmosphere,theyarecapableofgeneratingexcessivenoise.Therefore,mufflersaremountedonexhaustportsofairvalvesandactuatorstoreducenoiseandpreventoperatingpersonnelfrompossibleinjuryresultingnotonlyfromexposuretonoisebutalsofromhigh-speedairborneparticles.Thereareseveralreasonsforconsideringtheuseofpneumaticsystemsinsteadofhydraulicsystems.Liquidsexhibitgreaterinertiathandogases.Therefore,inhydraulicsystemstheweightofoilisapotentialproblemwhenacceleratinganddeceleratinganddeceleratingactuatorsandwhensuddenlyopeningandclosingvalves.DuetoNewton’slawofmotion(forceequalsmassmultipliedbyacceleration),theforcerequiredtoaccelerateoilismanytimesgreaterthanthatrequiredtoaccelerateanequalvolumeofair.Liquidsalsoexhibitgreaterviscositythandogases.Thisresultsinlargerfrictionalpressureandpowerlosses.Also,sincehydraulicsystemsuseafluidforeigntotheatmosphere,theyrequirespecialreservoirsandno-leaksystemsuseairwhichisexhausteddirectlybackintothesurroundingenvironment.Generallyspeaking,pneumaticsystemsarelessexpensivethanlessexpensivethanhydraulicsystems.However,becauseofthecompressibilityofair,itisimpossibletoobtainprecisecontrolledactuatorvelocitieswithpneumaticsystems.Also,precisepositioningcontrolisnotobtainable.Whilepneumaticpressuresarequitelowduetopressurescanbeashighas10,000psi.Thus,hydraulicscanbehigh-powersystems,whereaspneumaticsareconfinedtolow-powerapplications.Industrialapplicationsofpneumaticsystemsaregrowingatarapidpace.Underneathintroductioniswidelyusedinallkindsofpneumaticsystemvalve.Valveisawidelyusedmechanicalproductineachcountry'seconomy.Youcanfindvalvescommonlyusedinthefollowingfieldslikeoil,naturegas,coal,metallurgy,mining,refinery,pipetransportation,petrochemical,chemical,pharmacy,foodproduction,powerplant,watersupply/drainage,heatsupply,airsupply,marine,vehicle,airplane,spacecraft,military,newtech,irrigationandmanyotherflowingsystems.Thereareself-drivenvalvesandoperatedvalves.Self-drivenvalves(likesafetyvalve,reliefvalve,steamtrap,checkvalve)arefunctioningbyutilizingitsmechanicaldesignorthepressure,directionofitsflowmedium.Operatedvalves(likegatevalve,globevalve,ballvalve,butterflyvalve)arefunctioningbyactuator(manual,electric,hydraulic,pneumaticetc.)orthepressure,flowdirectionofitsmedium.Duetothedifferencesofpressure,temperature,flow,andphysical-chemicalcharacterofitsmedium,therearedifferentrequirementsindesigningandapplyingthepipelinesystem.Thereforetherearenumeroustypesofvalve.GASVALVEFromtheairvalveoperatingprinciplesofview,airvalveperformancewilldirectlyaffecttheworkofcompressortanks,airvalveforthefollowingrequirements:resistancelossessmall.Airvalvesizeandairflowresistancelossesofvalvesalwaysspeedandthesizeofthespring-loadededge.Gashigherspeed,thegreatertheenergylosses;Spring-loadededgetoolarge,thelossisgreatresistance,thesizeoftheairvalvemovementdesignguidelinestodeterminethereasonablenessofthelaw.Airvalveclosedtimely,rapid,notleakclosedtoimprovetheefficiencyofmachinesandextendeduseperiod.Longlife,workreliable.Lifeisthemainfactorrestrictingairvalveandspring-loadedvalvesquality,thegenerallong-termcontinuousoperationofthecompressorstolife80hours;Formobile,short-termorintermittentoperationofcompressors,mayrequireslightlymore.Airvalveandpiston-typecompressorsaretotheimportantcomponentsisoneofthecomponentseasilydamaged.Itwillhaveadirectimpactonthedisplacementcompressors,powerconsumptionandreliabilityofoperation,thecurrentcompressorisfastdirection,androtationalspeedlimitisoneofthekeyissuesinimprovingairvalve.Piston-typecompressorstypicallyusethe"automaticvalve"thattheairvalveisopenedandclosedvalvesonthepressureonbothsidestoachievepoor,andthereisnootherdrive.PNEUMATICVALVEPneumaticvalvesregulatethetemperatureinthecontextnominalpressureandmayadjustvariousfluids,gasesandsteam,pneumatic-valveclosed,leakagesmall.Pneumatic-valveattheroleoftheimplementingagenciescouldreachagasopenorgasshutpurposes.Pneumaticvalvesregulatethepneumaticenforcementagenciesandregulatoryvalvestwo.Enforcementagenciestopromotetheimplementationofdevicesinstalled,itcompressedair-driven,exportthrust;Regulationvalvesarepartoftheimplementationofdevicestoregulatedirectcontactwiththemedia,regulatorymediumflow.Thepneumatic-valvestructurewithsimple,reliableoperation,exportthrustlargemaintenanceconvenientandinexpensive,suchasfireblastmeritspneumatic-valvewidelyusedforchemical,oil,metallurgical,electrical,textileandotherindustrialproductionprocessesautopilotandremotecontrol.PRESSUREREGULATINGVALVEpressureregulatingvalveisarelianceonexternalenergytransfermediumitselfwaspressurechangespressure-typeautomaticadjustmentofproduct,youcanadjustthevalveinthepressureequipmentdebuggingprocessinaccordancewiththeirownprocessespressureregulatingvalvesfortheguidecommandsystemsetpressureafterpressureregulatingvalvesvalue,pressureregulatingvalveswillbenaturalgaspressureregulatingvalves,thepressureforyoutosetandautomaticallymaintainitsconstant,pressureregulatingvalvesinthecontrolroomforyourremotecontroloxygenflowdownstream.Flowwillbeusedforon-siteoxygenpressureregulationandfeedbacktocontroltheactualprocessparameterstocontrolthedistance.Youcaneasilyadjusttheoxygenpressure.气压系统及各种阀门的基本介绍气压系统是用压力气体传递和控制动力，正如名称所表明的那样，气压系统通常用空气（不用其他气体）作为流体介质，因为空气是安全、成本低而又随处可得的流体，在系统部件中产生电弧有可能点燃泄漏物的场合下（使用空气作为介质）尤其安全。在气压系统中，压缩机用来压缩并供应所需的空气。压缩机一般有活塞式、叶片式和螺旋式等类型。压缩机基本上是根据理想气体法则，通过减小气体体积来增加气体压力的。气压系统通常考虑采用大的中央空气压缩机作为一个无限量的气源，这类似于电力系统中只要将插头插入插座便可获得电能。用这种方法，压力气体可以从气源输送到整个工厂的各个角落，压力气体可通过空气滤清器除去污物，这些污物可能会损坏气动组件的精密配合部件如阀和气缸等，随后输送到各个回路中，接着空气流经减压阀以减小气压值适合某一回路使用。因为空气不是好的润滑剂（包括20%的氧气），气压系统需要一个油雾器将细小的油雾注射到经过减压阀的空气中，这有助于减少气动组件精密配合运动件的磨损。由于来自大气中的空气含不同数量的水分，这些水分是有害的，它可以带走润滑剂引起过分磨损和腐蚀，因此，在一些使用场合中，要用空气干燥器来除去这些有害的水分。由于气压系统直接向大气排气，会产生过大噪声，因此可在气阀和执行组件排气口安装消声器来降低噪声，以防止操作人员因接触噪声及高速空气粒子有可能引发的伤害。用气动系统代替液压系统有以下几条理由：液体的惯性远比气体大，因此，在液压系统中，当执行组件加速减速和阀突然开启关闭时，油液的质量便是一个潜在的问题，根据牛顿运动定律（力等于质量乘以加速度），产生加速运动油液所需力要比加速同等体积空气所需的力高出许多倍。液体比气体具有更大的粘性，这会因为内摩擦而引起更大的压力和功率损失；另外，由于液压系统使用的液体要与大气隔绝，故它们需要特殊的油箱和无泄漏系统设计。气压系统使用可以直接排到周围环境中的空气，一般来说气压系统没有液体系统昂贵。然而，由于空气的可压缩性，使得气压系统执行组件不可能得到精确的速度控制和位置控制。气压系统由于压缩机局限，其系统压力相当低（低于250psi），而液压力可达10000psi之高，因此液压系统可以是大功率系统，而气动系统仅用于小功率系统。下面介绍广泛应用于气压系统的各种阀门。阀门是国民经济建设中使用极为广泛的一种机械产品。阀门在石油、天然气、煤炭、冶金、和矿石的开采、提炼加工和管道输送系统中；在石油化工、化工产品，医药和食品生产系统中；在水电、火电和核电的电力生产系统中；在城建的给排水、供热和供气系统中；在冶金生产系统中；在船舶、车辆、飞机、航天以及各种运动机械的使用流体系统中；在国防生产以及新技术领域里；在农业排灌系统中都有大量的需求。阀门分