轮机专业英语5

2047.Whichofthefollowingtermswouldbestdescribethetemperatureatwhichaliquidboilsatagivenpressure?A.Degreeofsaturation.B.Saturationtemperature.C.Superheatedtemperature.D.Degreeofsuperheat.注：饱和温度是指在给定的压力下液体蒸发的温度，故选B2048.2048.Inacompressionrefrigerationcycle，thetemperatureoftheliquidrefrigerantexperiencesitsgreatestdecreaseinthe____.A.evaporatorB.compressorC.expansionvalveD.condenser注：在压缩式制冷循环中，液态制冷剂的温度在膨胀阀处下降最大，故选c2049.Whichofthelistedstatementsiscorrectconcerningrefrigerationsystems?A.Dehydratorsmustbeusedcontinuouslyinarefrigerationsystem.B.A25tonrefrigerationsystemhasthesamecoolingeffectasmelting25tonsoficein24hours.C.Athermostaticexpansionvalveisusedtocontrolrefrigeratedspacetemperature.D.Theliquidreceiverfunctionstocollectandremovenon-condensablegases.注：25冷吨的制冷系统与在24小时之内溶化25吨冰具有同样的冷却效果，故选B2050.2050.Whichoftheconditionslistedwillcausearefrigerationcompressortorunconstantlywithoutsimultaneouslydecreasingthetemperatureintherefrigeratedspace?A.Shortageofrefrigerantoil.B.Slightshortageofrefrigerant.

C.Excessivecondensercoolingwaterflow.D.Faultyexpansionvalve.注：如果制冷压縮机持续运转但不能实现降温，可能原因是制冷剂不足，故选B2051.Thermostaticexpansionvalvescanbeadjustedfor.A.suctionpressureonlyB.headpressureonly：C.superheatonlyD.suctionpressureandboxtemperature注：在四个选项中，热力膨胀阀仅用来调节过热度，故选C2052.2052.Acondenserisavesselinwhichisdeprivedofitslatentheatofvaporizationandsochangedtoitsliquidstate.A.seawaterB.freshwaterC.vapourD.gas注：冷凝器是这样一种容器，它能使蒸汽释放潜热并转变为液态，故选C2053.*Zincrodsareinstalledintherefrigerationsystem.A.liquidstrainerB.liquidreceiverC.saltwatercondenserD.evaporator注：锌棒安装在制冷系统的海水冷凝器中，选C2054.Whichofthestatementslistedconcerningheattransferiscorrect?A.Heatisalwaystransferredataconstantrate.B.Heattransferrateincreasesastemperaturedifferenceincreases.C.Therateofheattransferisnotaffectedbytemperaturedifference.D.Thehightemperatureregionisknownasaheatsink.注：传热速率随着温差的增大而增大，选B2055.Theheatremovedfromtherefrigerantinthecondenserofarefrigerationplantisthe，A.latentheatofexpansionB.sensibleheatofcondensationC.heatofcompressionD.alloftheabove注：从制冷设备冷凝器冷剂中去除的热量叫做压縮热，选C2056.Refrigerantenteringthecompressorofarefrigerationsystemshouldbeinwhichofthefollowingconditions?A.Sub-cooledliquid.B.Sub-cooledvapor.C.Superheatedvapor.D.Liquid.注：进人制冷系统压缩机的冷剂应该是处于过热蒸气状态，选C2057.Afluidcoilwilllargequantitiesofheatwhenitchangesstatefromaliquidtoava-por.A.releaseB.absorbC.developD.regenerate注：蒸发盘管在从液态变成蒸气状态时吸收大量热量，选B2058.Thepressurerangebetweenthesystemcutinandcutoutpressuresinarefrigerationunitisknownas.A.opposingoperationaldragB.pressuredistributionC.differentialD.systempurge注：制冷装置接通压力和断开压力间的压力变化范围被叫做压力差，选Cdrag摩擦力2059.2059.Inadirectexpansiontypemulti-boxrefrigerationsystem，thecompressorissetuptocycleonandoffbythe.A.pressurestatB.highpressurecutoutC.solenoidvalveD.lowpressurecutoutswitch注：直接膨胀式多冷库制冷系统，压缩机被设计成靠低压断路器开关（低压控制器）控制启停，故选D2061.2061.Thepurposeoftherefrigerationsystemlowpressurecutoutswitchisto.A.protectthecompressorfromliquidfloodbackB.protectthecompressor&omlowdischargepressureC.startandstopthecompressoruponsystemdemandD.startthecompressorafteradropintheevaporatorpressure注：制冷系统低压断路器开关的用途是根据需要启停压縮机，选C2062.Thereceiverusedinarefrigerationsystem___.A.storesliquidrefrigerantB.collectsnon-condensablegasesC.allowsrefrigerantsub-coolingD.preventscompressorsurging注：制冷系统的贮液器用于存储液态制冷剂，选A2063.2063.Hotgasbypassisoneofthemethodsusedto.A.relieveexcessivecompressorheadpressureB.produceflashgasattheexpansionvalveC.reducefloodingofthereceiveratlowloadD.defrosttheevaporatorcoils注：蒸发器盘管除霜的方法之一是热气旁通，选D2064.Constantsuperheatismaintainedattheevaporatoroutletofarefrigerationcoilbya一.A.solenoidvalveB.lowpressurecutoutswitchC.kingvalveD.thermalexpansionvalve注：制冷盘管的蒸发器出口通过热力膨胀阀来保持恒定的过热度，选D2065.2065.Onefunctionofthethermalexpansionvalveisto.A.actasapilotfromthesolenoidvalveB.regulatetheamountofrefrigerantflowtothecoilC.regulatethewaterflowD.turnthecompressoroffandon注：热力膨胀阀的作用之一是调节流向盘管的冷剂流量，选B2066.Thethermalexpansionvalvereactsdirectlytothe.A.temperatureinthespacebeingcooledB.liquidrefrigerantpressureatthesolenoidvalveC.pressuredropacrosstheevaporatorcoilsD.refrigerantgassuperheatatthecoiloutlet注：热力膨胀阀直接对盘管出口处冷剂气体的过热度作出反应，选D2067.2067.Inthepresenceofanopenflameorhotsurfaces，chlorinatedfluorocarbonrefrigerantsde-composeandform-A.petroleumcrystalsB.phosgenegasC.watervaporD.carbonmonoxide注：在与明火或高温表面接触时，氯化碳氟化合物冷剂会分解并形成光气，选B。chlorinatedfluorocarbon氯化碳氟化合物，phosgenegas光气02068.CFCrefrigerantsexposedtohightemperatureordirectflame,willdecomposeandmaypro-duce-A.methylchlorideB.ammoniaC.hydrofluoricacidD.ozone注：不含氢的氯氟烃冷剂暴露于高温或明火下会分解，可能会产生氢氟酸，选C。methylchloride甲基氣，hydrofluoricacid氢氟酸，ozone臭氧2069.Whentheheatloadbeginstoincrease,theneedlevalveofanexpansionvalvewill.A.moveinanopeningdirectionB.moveinaclosingdirectionC.eitheropenorcloseD.notmoveatall注：当机器热负荷开始增加，膨胀阀的针阀会向开启方向移动，故选A2070.2070.Whentherefrigerationdemandissmall，.A.theexpansionvalvewillmovetowardthewideopenpositionB.theexpansionvalvewillmovetowardtheclosingpositionC.thefeelerbulbwillconveysthehightemperatureD.thesuperheatdegreewillraise注：当制冷需求变小，膨胀阀将向关闭方向移动，故选B2071.Thethermostaticvalvehasathrottlingaction,thatistosaythevalvecan.A.stoptherefrigerantfromflowingB.forcetherefrigeranttoflowC.causetherefrigerantpressuretoriseD.causetherefrigerantpressuretofall注：热力膨胀阀有节流作用，即该阀能导致冷剂压力下降，选D2072.2072.Thethermalexpansionvalverespondstothe.A.amountofsuperheatinthevaporleavingthecoilB.amountofsuperheatintheliquidC.temperatureintheevaporatorcoilsD.pressureintheevaporatorcoils注：热力膨胀阀会对盘管出口的蒸气过热度作出反应，选A2073.Thebulbforthethermalexpansionvalveislocated.A.inthemiddleofevaporatorcoilsB.neartheevaporatorcoiloutletC.neartheevaporatorcoilinletD.onthebottomrowofevaporatorcoils注：热力膨胀阀的感温包位于蒸发盘管出口附近，选B2074.2074.Ifthecompressorrunscontinually，thecausemightbethe.A.high-pressurecutoutswitchisjammedopenB.low-pressureswitchisjammedshutC.thermalbulbisnotoperatingproperlyD.scaletrapisclogged注：压缩机持续运转，原因可能是低压开关卡在关闭的位置，选B2075.Thesolenoidvalvecanbetypedasa.A.thermalvalveB.magneticstopvalveC.bellowsvalveD.bimetallicvalve注：电磁阀是一种电磁截止阀，选B2076.2076.Intermsofpressureandtemperatureintherefrigerantinthecompressor，whathappenstotheprimary?A.Itspressureandtemperaturearebothlowered.B.Itspressureandtemperaturearebothraised.C.Itspressureisloweredanditstemperatureisraised.D.Itspressureisraisedanditstemperatureislowered.注：压缩机中冷剂的压力和温度都升高，选B2077.WhatisthepurposeofsubcoolingR-12inthecondenser?A.Toincreasethesystemefficiencybysensibleheattransfer.B.Tostoptheliquidfromflashing.C.Toreducetheloadonthecompressor.D.Toremovelatentheatofvaporizationandthesuctionpipingtransfer.注：对冷凝器中R-12进行过冷的目的是防止液体闪发，选B2078.2078.Thepurposeofthepurgevalveatthetopofthecondenserinarefrigeratingsystemisto__-A.removeanyairthatmayaccumulateinthesystemB.takeoutunpleasantfumesfromtherefrigerantC.ventoffexcessrefrigerantinanemergencyD.permitopeningtherefrigeratingsystemforcleaningandinspecting注：位于制冷系统中冷凝器顶部的放气阀的主要作用是排出系统中可能积聚的任何气体，选A2079.Thedeviceusedforlow-pressurecontrolandhigh-pressurecutoutonacompressoriscalleda.A.cutoutB.pressurecontrollerC.controllerswitchD.cutoutswitch注：压缩机中用于低压控制和高压断开的设备是压力控制器，选B2080.2080.Wherearethezincplateslocated?.A.SaltwatersideofthecondenserB.RefrigerantsideofthecondenserC.IntheevaporatorcoilsD.Inthesuctionstrainer注：锌块位于冷凝器的海水端，选A2081.Thedevice,whichisinstalledinthecompressorsuctionlinetopreventliquidfromenteringthecompressorwhenhotgasdefrosting，iscalleda?A.re-evaporatorB.receiverC.dehydratorD.solenoid注：在热气融霜时，位于压縮机吸入管路用以防止液体进人压缩机的设备是再蒸发器（回热器），故选A。dehydrator干燥器2082.2082.Acentrifugalcompressor'spurgerecoveryunit.A.reclaimswaterB.purgesairwithoutlosingrefrigerant

C.purgesairwithsomelossofrefrigerantD.purgeslubeoilfromtherefrigerant注：离心式压缩机的驱气回收装置不损失冷剂就可去除气体，选BLesson17MarineRefrigerationManagementandFaultDiagnosis(船舶制冷装置的管理和故障诊断）2083.Whichofthefollowingmaycausethatthecompressorcutsoffonhighpressurecutoutinarefrigerationplant?Ifaultycondensing；IItoofewrefrigerant；IIIhighdischargepressure.A.anyofIandIIIB.anyofIandIIC.anyofIIandIIID.anyofI,IIandIII注：冷凝故障、压縮机排出压力偏高，都会使高压控制器产生动作，而制冷剂不足会引起低压控制器动作，故选A2084.2084.Whichofthefollowingmaycausethatexcessivelywarmwaterleavesthecondenserinare-frigerationplant?Itoolittlecoolingwater；IItoomuchcoolingwater；IIItoowarmcoolerwater.A.IonlyB.anyofI,IIandIIIC.anyofIandIIID.anyofIandII注：冷却水不足、冷却水温过高，都会使制冷装置冷凝器中冷却水出口温度偏高，故选C2085.Thepresenceofairinthecondenserofarefrigerationsystemwillthecondensingpressure.A.increaseB.reduceC.maintainconstantD.noneoftheaboveistrue注：制冷装置中，冷凝器中存在空气将会使冷凝压力升高，故选A2086.2086.MoistureshouldbekeptoutofanR-12systembecauseittendstocause.A.icingoftheautomaticcontrolsB.embrittlementofsomepartsoftheautomaticcontrolsC.sludgeinthelubricatingoilD.alloftheabove注：R12制冷系统中存在水分，会引起自动控制器结冰、某些部件脆化以及污染滑油等，故选D2087.Airthatmayenterarefrigerationplanttendstocollectinthe.A.upperpartofthereceiverB.upperpartofthecondenser

C.downstreamendofthecoolingcoilD.outletendofthecondenser注：进入到制冷装置的空气积聚在冷凝器的上半部分，故选B2088.2088.Insufficientrefrigerantinarefrigerationplantmayresultin.A.highdischargepressureB.frostingofthecrankcase

C.hightemperatureoftheoverboardwaterD.lowsuctionpressureofcompressor注：制冷系统中冷剂不足，会导致压缩机吸入压力偏低，故选D2089.WhichwillcausethehighpressurecutouttostopthecompressorinaR-22system?A.Condenserleakage.B.Ashortageofliquidrefrigerant.C.Excessivefrostontheevaporator.D.Notenoughcondensercoolingwater.注：冷凝器冷却水量不足，会引起冷凝压力偏高，压缩机高压控制器会产生动作，故选D2090.2090.Aruptureddiaphragminathermostaticexpansionvalvewillcausethevalveto.A.openB.closeC,remaininitspositionD.floodtheevaporatorwithrefrigerant注：如果热力膨胀阀的膜片破裂，膨胀阀将关闭，故选B2091.Theshutteroftheevaporatorwasblockedwith，itmeanstherewastoomuchevapo-ration.A.iceB.woodenboardC.ironplateD.cottonwaste注：蒸发器的格栅被冰堵塞了，表明蒸发过度，故选A2092.2092.Faultyoperationofanysystemisindicatedbyverydefinite.A.symptomsB.samplesC.tracesD.tracks注：任何系统的故障运行，都会以某种征兆显示，故选A2093.Ifarefrigerationcompressorisrunningcontinuouslywithoutloweringtemperatureasnormalintherefrigerator，thetroublemaybe.A.excessivecondensercoolingwaterB.warmfoodintherefrigeratorC.ashortageofrefrigerantD.sshortageofcompressoroil注：制冷压缩机持续运转但冷库不降温，可能原因是制冷剂不足，故选C2094.2094.Thecoloroftheflameonahalidetorchwithoutanyrefrigerantpresentis,A.blueB.greenC.orangeD.purple注：卤素检漏灯在无制冷剂时火焰呈蓝色，故选A2095.Athermostaticexpansionvalveisproperlycontrollingevaporatorsuperheat.Adjustingthisvalvetolowerthesuperheatwillresultina/an.A.evaporatorpressuredecreaseB.evaporatorcoilover-feedC.evaporatorcapacityincreaseD.expansionvalvediaphragmrupture注：热力膨胀阀用于控制蒸发器的过热度，当调节膨胀,以减少过热度时，将使蒸发盘管流量过大，故选B2096.2096.Whenyouadjustathermostaticexpansionvalve，.A.refrigerantmustbebledoffthesensinglinebeforeadjustmentsaremadeB.allrefrigerantmustbepumpedintothereceiverbeforeadjustmentsaremadeC.timemustbeallowedforconditionstostabilizeintheevaporatorbeforefurtheradjustmentsaremadeD.allrefrigerantmustberoutedthroughthedehydratorwhilechangingthesuperheatsetting注：当调节热力膨胀阀时，在作进一步调节前；应有足够时间让蒸发器工况稳定，故选C2097.Therefrigerationsystemlowpressurecutoutswitchisactuatedby.A.anelectricsystemmanagerB.asensingbulbatthetailcoiloftheevaporatorC.pressurechangesinthesuctionlineD.failureofthekingsolenoidvalve注：制冷系统的低压控制器是由吸入管路的压力变化来产生动作的，故选c2098.Thesensinglineforthelowpressurecutoutswitchtoarefrigerationsystemislocated.A.inthechillboxB.beforethereceiverC.onthesuctionsideofthecompressorD.onthedischargesideofthecompressor注：制冷系统低压控制器的输入（感应）管路位于压缩机的吸人侧，故选c2099.2099.Thepurposeofthelowpressurecut-outswitchisto.A.maintainliquidrefrigerantatthesuctionofthecompressorB.maintainapresetsuctionpressuretothecompressorC.startandstopthecompressoratpresetoperatingpressuresD.operateatminimumefficiency注：制冷系统低压控制器的作用是在预先设定的压力下启、停压缩机，故选c2100.Shortcyclingofarefrigerationcompressorrefersto.A.frequentlygroundingoutB.frequentlystartingandstoppingC.runningtoofastD.runningtooslow注：制冷压缩机"短循环"，指的是压缩机启、停频繁，故选B2101.2101.Onallvesselsequippedwithrefrigerationunitsofover20cubicfootcapacity,_______A.agasmasksuitableforprotectionagainsteachrefrigerantused,oraselfcontainedbreathingapparatusmustbeprovidedB.itisthesoleresponsibilityofthechiefengineertoascertainthatallmembersoftheen-gineeringdepartmentarefamiliarwiththeuseofgasmasksorbreathingapparatusC.sparechargesshallbecarriedforatleast50%ofeachsizeandvarietyofgasmasksand/orselfcontainedbreathingapparatusD.alloftheabove注：具有容积在20立方英尺以上制冷系统的船舶，必须有合适的气体面罩（能防止所使用的制冷剂产生的危害）或自带式呼吸器，故选A2102.Whenliquidreachesthecompressorofarefrigerationsystemthroughthesuctionline,theconditioniscalled?A.floodingbackB.superheatingG.overflowingD.recycling注：当液态制冷剂通过压缩机吸人管到达制冷系统的压缩机时，会产生"液击"现象，故选A2103.2103.TheFIRSTthingtodotoensurethatarefrigerationunitwillnotstartwhileundergoingre-pairs，isto一.A.secureandtagtheelectricalcircuitB.placeacrowbarintheflywheeloftheunitC.informallpersonsintheareanottostattttheunitD.makealogbookentry注：在进行维修工作时，为确保制冷装置不启动，应首先切断电路，故选A2104.Withreferencetoavessel'sstructuralintegrity,themostsignificantcharacteristicofacryo-genicliquidisits.A.capabilityofcausingbrittlefracturesB.highlycorrosiveactiononmildsteelC.vaporcloudwhichreactsviolentlywithsaltwaterD.toxicityatatmosphericpressure注：低温液体对船舶结构产生的最大危害是发生"冷脆"，故选A2105.2105.Personnelworkingwithrefrigerationsystems,andsubjecttotheexposureofrefrigerantsshouldwear.A.faceshieldB.arespiratorG.rubberglovesD.anallpurposegasmask注：如果对制冷系统进行维修工作，可能会接触制冷剂，人员应戴合适的面罩，故选A2106.Forsafestorage,themaximumallowabletemperaturetowhichrefrigerantbottlesshouldbeexposedis?A.100摄氏度B.125摄氏度C.150摄氏度D.175摄氏度注：为了安全起见，制冷剂瓶接触的温度不得高于125摄氏度，故选B2107.2107.Arefrigerationsystemcontaminatedwithmoisturecanbeaffectedby.A.acidformationB.sludgeformationC.iceintheexpansionvalveD.alloftheabove注：制冷系统中存在水分，会形成酸性物质、沉淀，并在膨胀阀处结冰，故选D2108.Whichofthelistedoperationswillcauseanautomaticallycontrolledrefrigerationcompressortorestart?A.Closingofthesolenoidvalve.B.Closingoftheexpansionvalve.C.Anincreaseinthesuctionpressure.D.Decreasingthesuctionpressure.注：吸人压力升高会引起自动控制的制冷压缩机重新启动，故选c2109.2109.Moistureintherefrigerantmay.A.freezeontheexpansionvalveseatandreducetheflowofliquidrefrigerantB.emulsifytheoilinthecondenserC.freezeinthekingvalveD.clogtheoiltrap注：制冷系统中的水分会在膨胀阀座结冰，并会减少制冷剂的流量，故选A2110.Moistureinarefrigerationsystemcancause.A.freezingtheexpansionvalveclosedB.corrosionofsystempipingG.impropertemperatureregulationD.alloftheabove注：制冷系统中的水分会造成膨胀阀结冰，系统管路腐蚀并使温度调节不正常，故选D2111.2111.Whichoftheproblemslistedcouldbeindicatedifasightglassintherefrigerantliquidlineisfullofbubbles?A.Properrefrigerantcharge.B.Faultyexpansionvalve.C.Insufficientrefrigerant.D.Solenoidvalvestuckopen.注：如果制冷剂液态管路中的示液镜充满气泡，可能表明制冷剂不足，故选c2112.AliquidindicatorsightglassisusefulindeterminingwhetherornotarefrigerationsystemissufficientlychargeD.Itisgenerallylocatedinthe.A.highpressureliquidlineB.lowpressureliquidlineC.highpressurevaporlineD.lowpressurevaporline注：制冷系统示液镜用于确定冷剂是否充分充注，它通常位于高压液态管路，故选A2113.2113.Ifaliquidsightflowindicatorinarefrigerationsystemshowsgasbubblesinmotionpassinginsideoftheglass，thereis.A.toomuchrefrigerantinthesystemB.oilentrainedintherefrigerantC.lessthanafullchargeofrefrigerantinthesystemD.icecrystalsformingintherefrigerant注：如果制冷系统液态管路中的示液镜充满气泡，可能表明制冷剂不足，故选c2114.Asightglassisinstalledintheliquidlinetoindicatetheconditionoftherefrigerantchargeandmayalsoindicatethe.A.conditionoftheexpansionvalveB.moistureinthesystemC.conditionofthecompressorsuctionvalvesD.condensertemperature注：制冷系统液态管路中的示液镜可用来表示制冷剂的充注状况，也可用来显示系统中是否有水分，故选B2115.2115.Aliquidsightflowindicatorinarefrigerationsystemisexaminedandgasbubblesarenotedinmotionwiththefluidflow.Thismeans.A.thesystemisfullychargedB.thereisairleakinginfromthecondenserC.icecrystalsarefanningintherefrigerantD.thesystemcontainslessthanafullchargeofrefrigerant注：检査制冷系统液态管路中的示液镜，发现液流中有气泡。这表明制冷剂不足，故选D2116.Iftherefrigerationcompressorcrankcaseissweating,thecausemaybedueto_____.A.ashortageofrefrigerantB.thecompressorrunningcontinuouslyC.liquidrefrigerantreturningtothecompressorD.thecompressorshortcyclingonthehighpressurecutout注：如果制冷压缩机曲柄箱冒汗（有水珠），原因可能是液态制冷剂返回到压缩机，故选C2117.Arefrigerationsystemcompressorcrankcaseissweatingorunusuallycold.Thisisanindi-cationof.A.ashortageofrefrigerantinthesystemB.airinthesystemC.anaccumulationofliquidrefrigerantinthecrankcaseD.ashortageofoilinthecrankcase注：如果制冷压缩机曲柄箱冒汗（有水珠），原因可能是液态制冷剂积聚在曲柄箱，故选C2118.Refrigerationsystemcompressorcrankcasesweatingisanindicationof..A.insufficientlubeoilcirculatingthroughthesystemB.excessivecirculationoflubeoilthroughthesystemC.insufficientrefrigerantinthesystemD.anoverworkedcompressor注-如果制冷压缩机曲柄箱冒汗（有水珠），另一个原因可能是系统中循环的滑油过多，故选B2119.2119.Sweatingoftherefrigerationsystemcompressorcrankcaseiscausedby.A.toomuchsuperheatB.insufficientsuperheatC.suctionpressuretoolowD.excessiverefrigerantreturningtothecompressor注：如果制冷压缩机曲柄箱冒汗（有水珠），原因可能是过多的制冷剂返回到压缩机，故选D2120.Crankcasesweatinginarefrigerationsystemiscausedby.A.astucksolenoidvalveB.ashortageofrefrigerantC.toomuchoilincirculationD.toomuchsuperheat注：如果制冷压缩机曲柄箱冒汗（有水珠），另一个原因可能是系统中循环的滑油过多，故选c2121.2121.Ifarefrigerationsystemcompressorcrankcaseissweating,youshould.A.addrefrigeranttothesystemB.adjustthethermalexpansionvalvetothepropersettingC.adjustthefloatvalvetotheproperholdingpressureD.openthehandexpansionvalve注：如果制冷压缩机曲柄箱冒汗（有水珠），应调节热力膨胀阀到正常位置，故选B2122.Whenitisnecessarytoopenarefrigerationsystemforrepairsandthesystemwillbeopenformorethanafewminutes，theopenendsoithesystemshouldbe.A.dehydratedB.purgedC,pluggedD.evacuated注：如果要对制冷系统进行维修工作，系统需要打开一段时间，系统的开口端应塞住，故选c2123.2123.Acrackeddiaphragminathermostaticexpansionvalvewillcausethevalveto..A.returntoaneutralpositionB.floodtheevaporatorG.openD.close注：热力膨胀阀膜片裂开将引起膨胀阀关闭，故选D2124.Whichoftheproblemslistedrepresentsthemajordifficultyencounteredwiththermalex-pansionvalveoperation?A.Lubeoilpassingthroughthesystem.B.Moistureorforeignmattercollectingatthevalveseatandorifice.C.Variablespringtensioncausedbythechangingtemperature.D.Frostontheliquidline.注：热力膨胀阀阀座和节流孔积聚水分或杂质会对膨胀阀的工作造成影响，故选B2125.2125.Ifarefrigerationcompressorwereshortcyclingonthelowpressurecutoutswitch,theprob-ablecauseforthismightbethe.A.systemwasoverchargedwithrefrigerantB.highpressureswitchwasimproperlyadjustedC.expansionvalvestrainerswerefouledD.suctionvalveswereleakingslightly注：膨胀阀滤器脏堵，会引起低压控制器频繁动作，造成压缩机起、停频繁，故选c2126.Ifarefrigerationcrankcasecompressorwereshortcyclingonthelowpressurecutoutswitch，thecausemightbethatthe-A.systemwasoverchargedwithrefrigerantB.systemwaslowonrefrigerantC.suctionvalveswereleakingslightlyD.reliefvalvewasleakingslightly注：低压控制器频繁动作，造成压缩机起、停频繁，原因可能是系统中制冷剂不足，故选B2127.2127.Arefrigerationunitwilltendtoshortcyclewhenoperating.A.underheavyloadsB.duringhotgasdefrostC.underlightloadsD.duringstartingconditions注：制冷装置在低负荷运转时，容易产生压缩机起、停频繁，故选c2128.Ifarefrigerationcompressorisshortcyclingonhighheadpressure,youshould.A.purgethecondenserifthewatersideisdirtyB.checkforproperwaterflowthroughthecondenserC.increasethehighpressurecutoutsettingD.reducethecoolingwaterflow注：由于排压过高而使制冷压缩机起停频繁，应注意检查冷凝器是否有足够水流，故选B2129.2129.Therefrigerationcompressorinawatercooledrefrigerationsystemisshortcyclingonthehighpressurecutoutswitch.Onereasonforthiscouldbethe,A.systemislowonrefrigerantB.highpressurecutoutswitchisimproperlyadjustedC.dischargevalvesareleakingslightlyD.dischargevalvesareleakingexcessively注：水冷式制冷系统中，制冷压缩机由于高压控制器频繁动作而使压縮机起、停频繁，其中一个可能原因是高压控制器没有正确调节，故选B2130.Ifarefrigerationcompressorwillnotstart,thereasonmaybe.A.thepressureregulatingvalveisnotclosingB.anexcessivelackofrefrigerantinthesystemC.badlyleakingdischargevalvesD.wornpistonrings注：制冷系统中制冷剂严重不足，会引起制冷压缩机不能启动，故选B2131.2131.Whenarefrigerationcompressormotorfailstostart,theFIRSTthingthatshouldbecheckedforisa.A.looseexpansionvalvecontrolbulbB.lowdifferentialsettingontheH.P.cutoutC.blownfuseinthemotorcircuitD.faultysuctionpressureregulator注：制冷压縮机的电动机不能启动时，首先应检查电动机电路中熔断丝是否熔化，故选C2132.Ifalargedifferenceexistsbetweenthecompressordischargepressureandthepressurecor-respondingtotheexistingcondensingtemperatureinarefrigerationsystem,youshouldA.increasetheflowofthecoolingwaterthroughthecondenserB.adjustthehighpressurecutouttomaintainthedesiredpressureC.openthehotgasbypasstemporarilytoreducecapacityD.purgenon-condensablegasestoreducetheexcesspressure注：制冷系统中，如果压缩机的排出压力与冷凝温度对应的冷凝压力存在很大的差值，应放出不凝性气体以减少过高的压力，故选D2133.2133.Theaccumulationofairandothernon-condensablegasesinarefrigerationsystemwillA.causealossoftheliquidsealB.createavaporlockintheliquidreceiverC.collectinthecondenserD.causefoamingoftheoilinthecrankcase注：制冷系统中空气和其它不凝性气体总是积聚在冷凝器（的上半部分），故选c2134.Airenteringanair-cooledrefrigerationsystemisindicatedby.A.frostingoftheliquidlineB.higherthannormalheadpressureC.aclearsightglassD.abnormallycoldreeferboxes注：空冷式制冷系统，如果空气进入到系统，压缩机的排出压力会高于正常值，故选B2135.2135.Thepresenceofbubblesinarefrigerationsystemliquidlinemay.A.promoterefrigerantdehydrationB.beabsorbedinthereceiverC.causelowcondensingpressureD.carrymoistureandleadtocorrosion注：制冷系统液管存在气泡，会携带水分并导致腐蚀，故选D2136.Whichofthelistedstatementsisacharacteristicoftheliquidchargedpowerelementusedwiththermostaticexpansionvalves?A.Atthedesignedoperatingtemperature,theliquidrefrigerantchargehaschangedtoavapor.B.Theliquidrefrigeranttendstocollectatthebellowsordiaphragmandreducesthevalvesensitivity.C.Thesensingbulbisemptyofliquidrefrigerantchargeatthedesignedoperatingtemper-ature.D.Thesensingbulbisneveremptiedofliquidrefrigerantundernormaloperatingconditions.注：热力膨胀阀在正常工作时，其液体充注式感温包不可能没有液态制冷剂，故选D2137.2137.Excessivecirculationofthelubricatingoilwiththerefrigerantinarefrigerationsystemwillcause.A.carbondepositsonthecompressorsuctionvalvesB.theevaporatortemperaturetoincreaseC.rapidcorrosionofthethermalexpansionvalveD.nooperatingproblems注：制冷系统中，过多的滑油随制冷剂循环，会引起蒸发温度升高，故选B2138.Foamingoftheoilinarefrigerationcompressorcrankcaseiscausedby.A.refrigerantboilingoutofsolutionfromthelubeoilB.liquidrefrigerantfloodingthecompressorandsystemC.lubeoilviscositybeingreducedbyrefrigerantdilutionD.compressorsuctionpressuresuddenlyincreasing注：制冷压缩机曲柄箱油起泡是由制冷剂从滑油中蒸发出来所引起，故选A2139.2139.Inarefrigerationsystem,foamingofthecrankcaseoilmaycausethe.A.expansionvalvetooverfeedB.compressortoknockC.waterregulatingvalvetofailD.crankcasedrainstoplug注：制冷压缩机曲柄箱油起泡会引起压缩机敲缸，故选B2140.Excessiveoilfoaminginthecrankcaseofarefrigerationcompressorcanresultin?A.overheatedcompressorbearingsB.excesslubeoilviscosityC.carbondepositsonthecompressorpistonringsD.waxcrystalsforminginthelubricant注：制冷压缩机曲柄箱油泡沫过多会引起压缩机轴承过热，故选A2141.2141.Thesuddenreductionofpressureoccurringwithinthecrankcaseofarefrigerationcompres-sorduringstartingcausesthe.A.suddenevaporationofwaxcrystalsinthelubricantB.suddenevaporationofentrappedairinthelubricantC.releaseofrefrigerantfromtheoil/refrigerantmixtureD.releaseofdissolvedlubricantfromtherefrigerant注：制冷压缩机启动期间，曲柄箱压力突然下降，会引起制冷剂从混合物中蒸发出来，故选c2142.Theeffectofhighvaporsuperheatinarefrigerationsystem,isa/an.A.increasedcapacityofthecompressorB.moreefficientoperationofthethermalexpansionvalveC.decreasedcapacityofthecompressorD.lossofreceivercapacity注：制冷系统中，