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制冷空调专业英语UnitThreeLesson9ControlValvesLesson10LiquidPumpLesson11TheReciprocatingCompressorLesson12HeatExchanger1-2制冷空调专业英语UnitThree•NewWords&Expressions•Text•NotestotheText•ExerciseLesson11TheReciprocatingCompressor1-3制冷空调专业英语UnitThreeNewWords&ExpressionsLesson11曲柄轴；曲轴compressorn.压缩物,压缩机cylindern.圆筒,圆柱体,汽缸,柱面pistonn.[机]活塞extremelyadv.极端地,非常地psi=poundspersquareinch磅/平方英寸intaken.入口,进口,通风口exhaustn.排气,排气装置valven.阀crank-shaftn.1-4制冷空调专业英语UnitThreeLesson11NewWords&Expressions:包括一切的，全面的single-stageadj.单级的，单段的multistageadj.多级的double-actingadj.双动的actuatevt.开动,促使isoentropicadj.等熵的thermodynamicadj.热力学的,frictionn.摩擦,摩擦力inefficiencyn.无效率,无能over-alladj.1-5制冷空调专业英语UnitThreeTextThereciprocatingcompressorcanfurnishgasatpressuresofafewpoundsoratextremelyhighpressures,suchas35,000psi.1Thecharacteristicfeaturesofreciprocatingcompressorsarethesameasthoseofreciprocatingpumps─apiston,acylinderwithsuitableintakeandexhaustvalves,andacrank-shaftwithdrive.Everycompressorismadeupofoneormorebasicelements.Asingleelement,oragroupofelementsinparallel,comprisesasingle-stagecompressor.往复式压缩机能提供几磅压强的气体或压力极高（达35，000磅∕英寸）的气体。往复式压缩机的典型特征是和往复泵一样的，它们都具有活塞、气缸（气缸具有合适的进气阀和排气阀）和驱动曲柄轴。压缩机由一个或多个这些元件组成。单个或几组元件并行则构成单级压缩机。Lesson111-6制冷空调专业英语UnitThreeText:Manycompressionproblemsinvolveconditionsbeyondthepracticalcapabilityofasinglecompressionstage.Toogreatacompressionratiomaycauseexcessivedischargetemperatureorotherdesignproblems.Lesson11许多的压缩问题，超出了单级压缩的范围。因为压缩比过大，会导致排气温度过高，或者会引起其他设计问题。1-7制冷空调专业英语UnitThreeText:Itthereforemaybecomenecessarytocombineelementsorgroupsofelementsinseriestoformamultistageunit,inwhichtherewillbetwoormorestepsofcompression.Single-stageormultistageoperationiscommon,withdouble-actingcylinderusagebeinggeneral.2Lesson11因此，就必须使多组元件串联成多级压缩，它的压缩过程由二步或多步来完成。常见的是单段操作或多段操作，并且一般采用双作用气缸。。1-8制冷空调专业英语UnitThreeText:Gasbeingcompressedentersandleavesthecylinderthroughvalveswhicharesettobeactuatedwhenthepressuredifferencebetweencylindercontentsandoutsideconditionsisthatdesired3.Inletvalvesopenwhenthepressureinthecylinderisslightlybelowtheintakepressure.Dischargevalvesopenthepressureinthecylinderisslightlyabovethedischargepressure.Ifmulti-stagecompressionisused,itisgeneralpracticetocoolthegasbetweenstages.Lesson11被压缩的气体通过阀门进出气缸，而这些阀门被设定成在气缸内外压差达到期望值才动作。当气缸内的压力稍低于进气压力时，进气阀打开；当气缸内的压力稍高于进气压力时，排气阀打开。如果采用多段压缩，一般是在各段之间对气体进行冷却。1-9制冷空调专业英语UnitThreeText:Dischargecharacteristicsofreciprocatingcompressorsaresimilartothoseofreciprocatingpumps.Compressoroperationisfundamentallythoughtofasbeingisoentropic,andefficienciesarereportedrelativetothisisoentropicbasis4.Lesson11往复式压缩机排气特点和往复泵的类似。压缩机的运行基本上认为是等熵的，且给出的效率与这个等熵基本相对应。1-10制冷空调专业英语UnitThreeText:Thermodynamiclossesandfluidfrictionaregroupedtogetherasacompressioninefficiency5.Mechanicalfrictionlossesaretermedmechanicalinefficiency.Anover-allcompressorefficiencywillbetheproductofthecompressionandmechanicalefficiency.Theover-allefficiencyofmostreciprocatingcompressorsis65to80percent.Lesson11热力损失和流体摩擦可归纳为压缩效率损失。机械摩擦损失就叫做机械损失。压缩机总效率应是压缩效率和机械效率的乘积。大多数往复式压缩机的总效率为65%～80%。1-11制冷空调专业英语UnitThreeNotestotheTextLesson111-12制冷空调专业英语UnitThreeNotestotheText1.Thereciprocatingcompressorcanfurnishgasatpressuresofafewpoundsoratextremelyhighpressures,suchas35,000psi.Lesson11往复式压缩机能提供几磅压强的气体或压力极高（达35，000磅∕英寸）的气体。areciprocatingcompressor往复式压缩机容积式压缩机(positive-displacementcompressors)可分为二大类：一类是往复式(Reciprocating)结构；另一类是回转式(Rotary)结构。1-13制冷空调专业英语UnitThreeNotestotheText2.Single-stageormultistageoperationiscommon,withdouble-actingcylinderusagebeinggeneral.Lesson11句中介词短语with…作状语，表示附带说明情况。with后的double-actingcylinderusage为介词宾语，beinggeneral是usage的宾语补语，也可把with后的整个短语看作是复合宾语。。1-14制冷空调专业英语UnitThreeNotestotheText3.Gasbeingcompressedentersandleavesthecylinderthroughvalveswhicharesettobeactuatedwhenthepressuredifferencebetweencylindercontentsandoutsideconditionsisthatdesired.Lesson11句中beingcompressed作gas的定语。Tobeactuated为定语从句中的主语补语，when连接的时间状语从句是说明定语从句的谓语的。句末that是代词，代替前面的pressuredifference，而desired是过去分词，作that的后置定语。1-15制冷空调专业英语UnitThreeNotestotheText4.Compressoroperationisfundamentallythoughtofasbeingisoentropic,andefficienciesarereportedrelativetothisisoentropicbasisLesson11句中asbeing…和relativeto…各作并列分句中的主语补语。1-16制冷空调专业英语UnitThreeNotestotheText5.Thermodynamiclossesandfluidfrictionaregroupedtogetherasacompressioninefficiency..Lesson11句中Thermodynamiclosses和fluidfriction是主语,asacompressioninefficiency作主语补语。1-17制冷空调专业英语UnitThreeExerciseLesson11•Decidewhetherthefollowingstatementsaretrue(T)orfalse(F)accordingtothetext.1-18制冷空调专业英语UnitThreeExercise(T)(F)(F)(F)Lesson115.Toogreatacompressionratioisgoodforthewholesystem.1.Abasicgoalofcompressionofgasistodelivergasatahighpressure.2.Compressionofgasmaypromotetocirculateagasthroughaprocessorasystem3.Compressorsusingmethods3and4areintheintermittentclassandareknownaspositive-displacementcompressors.4.Everycompressorisonlymadeupofonebasicelements.