说专业应用化工技术（煤制油气专业）

Lesson3.2Pumps

contentwords1ExpressionsandTechnicalTerms2Text3Words泵pump[pʌmp]n.泵blowcase[blәu`keis]n.吹气箱elevation[͵eli`veiʃən]n.（1）断面图（2）海拔；标高member[`membә]n.结构单元；成员；构件；节；环中原子数chamber[`ʧeimbә]n.室；箱；容器其他inlet[`inlet]n.入口，进口；投料口；供料口discharge[dis`ʧaʤ]n.排放量；排放；排量v放电diameter[dai`æmitə]n.直径flexible[`fleksəbl]adj

柔软的，灵活的rod[rɔd]n.棒diaphragm[`daiəfræm]n.隔膜；膜片ExpressionsandTechnicalTerms规格对应职业岗位mechanicalenergy机械能positive-displacementpumps容积泵；排代泵centrifugalpumps离心泵reciprocatingpiston往复式活塞rotationalvelocity旋转速度kineticenergy动能pressureenergy压力能displacementpump位移泵reciprocatingpump往复泵rotarypump回转泵；转子泵text

Liquidaresometimesmovedbygravityfromelevatedtanks,orfroma“blowcase”(astoragevesselpressurizedfromanexternalsourceofcompressedgas),butbyfarthemostcommondevicesforthepurposearepumps.液体有时候可以由高位槽在重力的作用下被输送,或者可以通过压缩气箱来输送.(压缩气箱是由外界压缩气体加压后的储存气箱)但是目前用于液体输送的最常见的设备是泵.text

Pumpsincreasethemechanicalenergyoftheliquid,increasingitsvelocity,pressure,orelevation–orallthree.Thetwomajorclassesarepositive-displacement

pumpsandcentrifugalpumps.泵可以增加液体的机械能,机械能可使液体的速度,压力,高度增加或这三个性质.泵有两种主要的形式.即容积泵和离心泵.text

Positive-displacementunitsapplypressuredirectlytotheliquidbyareciprocatingpiston,orbyrotatingmemberswhichfromchambersalternatelyfilledbyandemptiedoftheliquid.Centrifugalpumpsgeneratehighrotationalvelocities,thenconverttheresultingkineticenergyoftheliquidtopressureenergy.容积泵可通过往复式活塞直接给液体加压或通过旋转构件给液体加压,旋转构件可使容积室内的液体交替的充满和排空.离心泵能使液体产生很高的旋转速度,然后把此速度所带来的动能转化为静压能.text

Positive-DisplacementPumpsTherearetwosubclassesofpositive-displacementpumps,reciprocatingpumpsandrotarypumps.Inreciprocatingpumps,thechamberisastationarycylinderthatcontainsaplungerorpiston;inrotarypumps,thechambermovesfrominlettodischargeandbacktotheinlet容积泵有两种形式的容积泵,即往复泵和回转泵.在往复泵中容积是固定的,里面有活塞或活柱.在回转泵中容积室是活动的可从入口移动到出口再返回到入口.text

Reciprocatingpumps

Pistonpumps,plungerpumps,anddiaphragmpumpsareexamplesofreciprocatingpumps.Inapistonpumps,liquidisdrawnthroughaninletcheckvalveintothecylinderbythewithdrawalofapiston,andthenisforcedoutthroughadischargecheckvalveonthereturnstroke.Mostpistonpumpsaredouble–actingwithliquidadmittedalternately.

往复泵 活塞泵,活柱泵,隔膜泵都是往复泵,在活塞泵中通过活塞的抽取将使液体从单向阀入口阀抽到气缸中,然后在回程中经过出口阀使液体强制排出.大多数的活塞泵都是两个同时交换使用.text

Forhigherpressures,plungerpumpsareused.Aheavy-walledcylinderofsmalldiametercontainsaclose-fittingreciprocatingplunger,whichismerelyanextensionofthepistonrod.Atthelimitofitsstroketheplungerfillsnearlyallthespaceinthecylinder.Plungerpumpsaresingle-actingandusuallyaremotor-driven.压力较高的情况下使用活柱泵,直径很小,气壁很厚的缸包含有一个安装紧密的往复式活柱,它仅仅是活塞柱的一种延伸形式.在活塞泵柱冲程中,活塞几乎充满容积室的整个空间.活柱泵单独使用通常是需要马达驱动的.text

Inadiaphragmpump,thereciprocatingmemberisaflexiblediaphragmofmetal,plastic,orrubber.Thiseliminatestheneedforpackingorsealsexposedtotheliquidbeingpumps,agreatadvantagewhenhandlingtoxicorcorrosiveliquids.AtypicalunitisshowninFig.9.

在隔膜泵中往复式的构件是一种灵活的金属,塑料,橡胶的膜片.这种膜片可以减少液体填充泵或密封泵的需要,这样就会使这种泵在处理有毒的,有腐蚀性液体时有很大好处,典型的隔膜泵如图9textFig9DiaphragmPumptext

RotaryPumps

Awidevarietyofrotarypositive-displacementpumpsareavailable.Theybearsuchnamesasgearpumps,lobepumps，screwpumps.TwoexamplesofgearpumpsareshowninFig.10.回转泵有大量的回转容积泵可用,这些泵主要有齿,轮泵,凸轮泵,螺杆泵.两种齿轮泵如图10textFig10Gearpumps(a)spur-gearpump;

(b)internal-gearpumptext

Unlikereciprocatingpumps,rotarypumpscontainnocheckvalves.Closetolerancesbetweenthemovingandstationarypartsminimizeleakagefromthedischargespacebacktothesuctionspace;theyalsolimittheoperatingspeed.Rotarypumpsoperatebestonclean,moderatelyviscousfluids,suchaslightlubricatingoil.Dischargepressuresupto200atmormorecanbeattained.与往复泵不同,回转泵无单向阀,在移动的构件与固定之间的公差很小,减少了从出口空间到入口空间的漏矢量,同时也限制了操作速度,回转泵最好适宜输送,洁净的黏度适中流体,如轻质润滑油,出口压力达到20.265Mpa或更多.

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CentrifugalPumpsInthesecondmajorclassofpumps,themechanicalenergyoftheliquidisincreasedbycentrifugalaction.Asimple,verycommon,exampleofacentrifugalpumpisshowninFig11离心泵在第二种泵即离心泵中,液体的机械能可通过离心泵的离心率可以提高,一种简单的常用的离心泵如图11所示.textFig11Single-suctioncentrifugalpumptext

Theliquidentersthroughasuctionconnectionconcentricwiththeaxisofahigh-speedrotaryelementcalledtheimpeller,whichcarriesradialvanesintegrallycastinit液体通过与高速旋转的构件即叶轮同轴的进口连接件进入到离心泵内.叶轮可夹带静像的叶片一起旋转text

Liquidflowsoutwardinthespacesbetweenthevansandleavestheimpeller.Inaproperlyfunctioningpump,thespacebetweenthevanesiscompletelyfilledwithliquidflowingwithoutcavitation.Theliquidleavingtheouterperipheryoftheimpellerisc