《水处理技术（双语）》课件-螺杆泵

Screwpumps螺杆泵螺杆泵（上）Screwpumps(I)螺杆泵在发达国家已广泛使用，国外多数称单螺杆泵为“莫诺泵”，德国称为“偏心转子泵”。Screwpumpshavebeenwidelyusedindevelopedcountries,mostforeigncountriescalledtheprogressivecavitypump"Monopump",Germanyiscalled"eccentricrotorpump".由于其优良的性能，近年来在国内的应用范围也在迅速扩大。它的最大特点是对介质的适应性强、流量平稳、压力脉动动小、自吸能力高，这是其它任何泵种所不能替代的。Duetoitsexcellentperformance,theapplicationrangeinChinaisalsoexpandingrapidlyinrecentyears.Itsbiggestfeaturesarestrongadaptabilitytothemedium,smoothflow,smallpressurepulsationandhighself-primingcapacity,whichcannotbereplacedbyanyotherpumptypes.螺杆泵的分类Classificationofscrewpumps（一）按螺杆数目分Bynumberofscrews1、单螺杆泵---单螺杆泵在泵体的内螺纹槽中啮合转动的泵。Singlescrewpump-Apumpinwhichasinglescrewpumpengagesandrotatesinagrooveintheinternalthreadofthepumpbody.2、双螺杆泵---由两个螺杆相互啮合输送液体的泵。

Twin-screwpump-apumpthatconsistsoftwoscrewsmeshingwitheachothertotransportliquid.3、多螺杆泵---由多个螺杆相互啮合输送液体的泵。Multi-screwpump-apumpthatconsistsofmultiplescrewsmeshingwitheachothertotransportliquid.图为双螺杆泵工作原理Workingprincipleoftwinscrewpump图为单螺杆泵工作原理Singlescrewpumpworkingprinciple图为多螺杆泵工作原理Multi-screwpumpworkingprinciple螺杆泵的分类Classificationofscrewpumps（二）按螺杆吸入方式分Byscrewinhalationmethod1、单吸式：油料从螺杆一端吸入，从另一端排出。Singlesuctiontype:Oilisdrawninfromoneendofthescrewanddischargedfromtheotherend.2、双吸式：油料从螺杆两端吸入，从中间排出。

Doublesuctiontype:Oilisdrawninfrombothendsofthescrewanddischargedfromthemiddle.图为单吸式螺杆泵Single-suctionscrewpumps图为双吸式螺杆泵Double-suctionscrewpumps螺杆泵的分类Classificationofscrewpumps单吸式和双吸式螺杆泵在油库中均有采用。Bothsingle-suctionanddouble-suctionscrewpumpsareusedinoildepots.按泵轴位置还可以分为卧式泵和立式泵。Itcanalsobedividedintohorizontalandverticalpumpsaccordingtothelocationofthepumpshaft.油库中常用的是卧式泵。Horizontalpumpsarecommonlyusedinoildepots.图为卧式泵Horizontalpumps图为立式泵VerticalPumps螺杆泵的分类Classificationofscrewpumps本节微课以目前市场最常用的单螺杆泵为例进行讲解Thismicro-lessonisanexampleofthemostcommonprogressivecavitypumpsinthemarkettoday单螺杆泵结构及工作原理结构Singlescrewpumpstructureandworkingprinciplestructure图为G型单螺杆泵的结构图StructurediagramofGtypesinglescrewpump如图所示：1出料口2拉杆3定子4螺杆轴5万向节总成6吸入口7连节轴8填料座9填料压盖10轴承座11轴承盖12电动机13连轴器14轴套15轴承16传动轴17底座Asshowninthefigure:1outlet2tierod3stator4screwshaft5universaljointassembly6suctionport7jointedshaft8packingseat9packinggland10bearingseat11bearingcover12motor13shaftcoupling14bushing15bearing16driveshaft17base螺杆泵的三个主要特征尺寸Thethreemaincharacteristicdimensionsofthescrewpump定子导程T(mm)：转子螺距的两倍StatorleadT(mm):twicetherotorpitch偏心距：e(mm)Eccentricdistance:e(mm)转子截面直径：D(mm)Rotorcross-sectiondiameter:D(mm)偏心率的大小直接影响到泵的性能、效率和寿命，还直接决定离心力的大小，从而影响到泵的振动、噪声，甚至橡胶定子的磨损等。Thesizeoftheeccentricitydirectlyaffectstheperformance,efficiencyandlifeofthepump,andalsodirectlydeterminesthesizeofthecentrifugalforce,whichaffectsthevibration,noise,andeventhewearoftherubberstator.偏心越小则泵的流量也越小，但泵的运行月稳定，寿命越长。Thesmallertheeccentricity,thesmallertheflowofthepump,butthemorestabletheoperationofthepump,thelongerthelife.离心泵的工作原理Theworkingprincipleofcentrifugalpump导程越大，则流量越大，但泵的长度尺寸也增大，而且使介质的轴流速度变大，直接影响泵的吸上能力。Thelargerthelead,thelargertheflow,butthelengthofthepumpsizealsoincreases,andtheaxialvelocityofthemediumbecomeslarger,whichdirectlyaffectsthesuctioncapacityofthepump.因此，选择恰当的e/D和T/D值是非常重要的。Therefore,itisveryimportanttochoosethepropere/DandT/Dvalues.采用大螺距、大偏心还是采用小螺距，小偏心应考虑到泵的性能参数、转子结构、使用情况和介质等多个因素。Theuseoflargepitch,largeeccentricityortheuseofsmallpitch,smalleccentricityshouldtakeintoaccounttheperformanceparametersofthepump,rotorstructure,useandmediaandmanyotherfactors.单螺杆泵的工作原理Theworkingprincipleofsinglescrewpump单螺杆泵是按回转啮合容积式原理工作的新型泵种。Theprogressivecavitypumpisanewtypeofpumpthatworksaccordingtotheprincipleofrotarymeshingdisplacement.主要工作部件是偏心螺杆（转子）和固定的衬套（定子）。Themainworkingpartsaretheeccentricscrew(rotor)andthefixedbushing(stator).由于该部件的特殊几何形状分别形成单独的密封容腔。Duetothespecialgeometryofthecomponentseparatesealingcavitiesareformed.单头阳螺旋转子在特殊的双头阴螺旋定子内偏心地转动（定子是柔软的），能沿泵中心线来回摆动，与定子始终保持啮合，介质由轴向均匀推行流动。Thesingle-headedmalespiralrotorrotateseccentricallyinaspecialdouble-headedfemalespiralstator(thestatorisflexible),whichcanswingbackandforthalongthepumpcenterline,alwaysengagingwiththestator,andthemediumflowsuniformlyfromtheaxialpush.单螺杆泵结构及工作原理结构Singlescrewpumpstructureandworkingprinciplestructure图为G型单螺杆泵的结构图1出料口2拉杆3定子4螺杆轴5万向节总成6吸入口7连节轴8填料座9填料压盖10轴承座11轴承盖12电动机13连轴器14轴套15轴承16传动轴17底座内部流速低，容积保持不变，压力稳定,因而不会产生涡流和搅动。Theinternalflowrateislow,thevolumeremainsconstant,andthepressureisstable,thusnovortexorchurningisgenerated.单螺杆泵被广泛用于各行业输送各类介质，恒压连续运行，无脉动，介质输送无破损，通过调节转速改变流量从而达到计量的目的。Singlescrewpumpiswidelyusedinvariousindustriestotransportallkindsofmedia,constantpressurecontinuousoperation,nopulsation,mediadeliverywithoutbreakage,changetheflowratebyadjustingthespeedtoachievethepurposeofmetering.单螺杆泵性能参数Singlescrewpumpperformanceparameters单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors单螺杆泵性能参数通常指流量、排出压力、吸入压力、转速、泵输入功率（轴功率）、介质特性、介质温度和介质的粘度等。Singlescrewpumpperformanceparametersusuallyrefertotheflowrate,dischargepressure,suctionpressure,speed,pumpinputpower(shaftpower),mediacharacteristics,mediatemperatureandviscosityofthemedia.流量受转速和介质粘度的影响，介质粘度也影响泵的输入功率，转速的选择与介质粘度有很大关系，还影响到泵的吸入性能等。Flowrateisaffectedbythespeedandmediumviscosity,mediumviscosityalsoaffectstheinputpowerofthepump,thechoiceofspeedandmediumviscosityhasagreatrelationship,butalsoaffectthesuctionperformanceofthepump,etc.设计泵时必须考虑这些参数之间的关系。Therelationshipbetweentheseparametersmustbeconsideredwhendesigningthepump.

流量Flow泵输入功率（轴功率）Pumpinputpower(shaftpower)排出压力Dischargepressure吸入压力Inhalationpressure转速RotationalSpeed介质特性MediaProperties介质温度Mediatemperature介质Media单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors（一）流量（Flow）流量是指泵在单位时间内输送的介质量或是泵每一转所排除的介质量。Flowratereferstotheamountofmediadeliveredbythepumpinaunitoftimeortheamountofmediaremovedbythepumpateachrevolution.体积流量用Q表示，质量流量用Qz表示。质量流量和体积流量的关系为：ThevolumetricflowrateisdenotedbyQandthemassflowrateisdenotedbyQz.Therelationshipbetweenmassflowrateandvolumeflowrateis图为污泥螺杆泵型号规格及参数Sludgescrewpumpmodelspecificationsandparameters单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors式中ρ——介质密度（Mediumdensity）（㎏/m3）。当转子转动一周，介质沿着轴向移动定子一个导程T，故转子转动一周，输送的介质体积为4eDT。Whereρ--mediumdensity(Mediumdensity)(㎏/m3).Whentherotorisrotatedonce,themediummovesthestatoralongtheaxialdirectionforoneleadT.Therefore,therotorisrotatedonce,andthevolumeofthemediumconveyedis4eDT.所以当转子转速为n时，单螺杆泵每秒的理论流量Q1为：

Sowhentherotorspeedisn,thetheoreticalflowratepersecondoftheprogressivecavitypumpQ1is:单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors实际上橡胶定子与转子的配合有过盈量，这必然会造成定子橡胶的变形。Infact,therubberstatorfitstherotorwithasurplus,whichinevitablycausesdeformationofthestatorrubber.因此，实际的理论流量要比如图所示计算的理论流量要小些。Therefore,theactualtheoreticalflowrateissmallerthanthetheoreticalflowratecalculatedasshowninthefigure.若要得到精确的实际理论流量值，可把转子装入定子后，截下长度为T的一段，对其注满水，再测量出注入水的体积。Togetanaccurateactualtheoreticalflowvalue,therotorcanbeloadedintothestator,cutoffasectionoflengthT,fillitwithwater,andthenmeasurethevolumeofwaterinjected.单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors泵的实际流量Q低于实际的理论流量Q1，这是由于定子和转子之间的配合实际如前面所述在运行时总会有些介质在排除压力作用下通过不密封的配合间隙流回到吸入腔。

TheactualflowrateofthepumpQislowerthantheactualtheoreticalflowrateQ1,becausetheactualfitbetweenthestatorandrotorasdescribedabovewillalwayshavesomemediumflowingbackintothesuctionchamberthroughtheunsealedfitgapunderexclusionpressureduringoperation.间隙越大，泄漏越多，密封腔两端的压力差越大，泄漏量也越大。Thelargerthegap,themoreleakage,andthegreaterthepressuredifferencebetweenthetwoendsofthesealingchamber,thegreatertheleakage.此外，介质输送过程中夹杂气体，也会造成流量降低。Inaddition,theentrainmentofgasinthemediaconveyingprocesswillalsocausetheflowratetodecrease.单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors（二）全压力Fullpressure

这里所说的全压力p即泵的压力差，是指排出压力pd和吸入压力ps之差。

Herethefullpressurepisthepumppressuredifference,referstothedischargepressurepdandthedifferencebetweenthesuctionpressureps.图为容积式泵Volumetricpumps单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors对于容积式泵来说，所谓的排出压力实际上就是泵的背压，也就是泵出口管路系统总的阻力，这是与离心式水泵概念完全不同的。所以单螺杆泵的压力差是与输送介质的性质无关；Forpositivedisplacementpumps,theso-calleddischargepressureisactuallythebackpressureofthepump,thatis,thetotalresistanceofthepumpoutletpipingsystem,whichiscompletelydifferentfromtheconceptofcentrifugalpumps.Sothepressuredifferenceoftheprogressivecavitypumpisnotrelatedtothenatureofthetransportmedium.需要注意的是输送的介质粘度越大，其在出口管路系统中的阻力也越大。

Itshouldbenotedthatthegreatertheviscosityoftheconveyedmedium,thegreatertheresistanceintheoutletpipingsystem.单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors（三）转速RotationalSpeed单螺杆泵可靠地工作必须限制转速。Aprogressivecavitypumpmustworkreliablybylimitingthespeedofrotation.影响选择转速的主要因素如下：Themainfactorsaffectingthechoiceofspeedareasfollows.1、吸入性能（Inhalationperformance）。

图为单螺杆泵固定转速时的性能参数Performanceparametersofsinglescrewpumpatfixedspeed单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors泵的转速越高，其流量也越大，转速不仅影响到泵吸入腔中的损失，而且当转速提高到一定程度，就会发生在吸入压力作用下的介质来不及进入或来不及充满打开的密封腔，使之出现某种程度的真空状态，输送介质就会大量析出所溶解的气体，以气泡形式分布在介质中，成为乳浊液，导致流量减少，甚至使泵不能正常工作。如果压力降到与一定温度下被输送介质的饱和蒸汽压力时泵内就会出现汽蚀现象。因此，转速受到吸入条件的限制。一般泵的转速越低，即介质的轴向流速越小，泵的吸入性能就越好。介质粘度越高，泵的吸入性能越差。介质的温度直接影响到介质的饱和蒸汽压力和某些介质的粘度。Thehigherthespeedofthepump,thegreatertheflowrate,thespeednotonlyaffectsthelossinthepumpsuctionchamber,andwhenthespeedincreasestoacertainextent,itwillhappenthatthemediumunderthesuctionpressureistoolatetoenterortoolatetofilltheopensealcavity,sothatacertaindegreeofvacuumstate,thetransportedmediumwillbealargenumberofdissolvedgasprecipitation,intheformofbubblesdistributedinthemedium,becomeemulsion,resultinginflowDecrease,andevenmakethepumpcannotworkproperly.Ifthepressuredropstothesaturatedvaporpressureofthemediumbeingconveyedatacertaintemperature,cavitationwilloccurinthepump.Therefore,thespeedislimitedbythesuctionconditions.Thelowerthegeneralpumpspeed,thatis,thesmallertheaxialflowrateofthemedium,thebetterthesuctionperformanceofthepump.Thehighertheviscosityofthemedium,theworsethesuctionperformanceofthepump.Thetemperatureofthemediumdirectlyaffectsthesaturationvaporpressureofthemediumandtheviscosityofcertainmedia.我国标准JB/T8644-1997《单螺杆泵型式与基本参数》编制时介质的轴向流速取不大于4~4.5m/s。China'sstandardJB/T8644-1997"singlescrewpumptypeandbasicparameters"whenthepreparationoftheaxialflowrateofthemediumisnotgreaterthan4~4.5m/s.单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors2、粘度（Viscosity）。当介质的粘度增大时，不仅会使在吸入压力作用下介质进入密封腔因阻力增大而更为困难，而且使转子对介质的剪切作用所产生的机械损失也增加。因此单螺杆泵运行时，若介质的粘度越大，则应选择越大的转速。Whentheviscosityofthemediumincreases,itwillnotonlymakeitmoredifficultforthemediumtoenterthesealingcavityundertheactionofsuctionpressureduetotheincreaseofresistance,butalsoincreasethemechanicallosscausedbytheshearactionoftherotoronthemedium.Therefore,whenthesinglescrewpumpisrunning,thehighertheviscosityofthemedium,thehigherthespeedshouldbeselected.图为常见介质的粘度表Viscositytableofcommonmedia单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors3、介质的磨损性。Abrasivenessofthemedium.介质的磨损性直接影响到转子和定子的耐磨程度，即影响到使用寿命。介质越“恶劣”（此处仅指所含的杂志、润滑性和流动性等），转子和定子必然越容易磨损，而且泵的转速越高，磨损就越快。Theabrasivenessofthemediumdirectlyaffectsthewearresistanceoftherotorandstator,i.e.,affectstheservicelife.The"harsher"themedium(hereonlyreferstothemagazine,lubricityandfluidity,etc.),themoreeasilytherotorandstatorareboundtowear,andthehigherthepumpspeed,thefasterthewear.单螺杆泵性能参数及其影响因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors4、介质为乳胶状液体时其结构对转速的敏感程度。

Thesensitivityofthestructuretorotationalspeedwhenthemediumisanemulsionliquid.如前面所述泵输送介质是为了从油污水中分离油时，要求不使介质乳化加剧，必须要求泵低速运行，通常转速不超过200r/min。Asmentionedearlierthepumpconveysthemediuminordertoseparatetheoilfromtheoilywater,therequirementsdonotmakethemediumemulsificationintensified,thepumpmustberequiredtorunatlowspeed,usuallythespeeddoesnotexceed200r/min.单螺杆泵特点及应用Singlescrewpumpfeaturesandapplications单螺杆泵因定子选用多种弹性材料制成，所以这种泵对高粘度达到80%流体的输送和含有硬质悬浮颗粒介质或含有纤维介质的输送，有一般泵种所不能胜任的特性。

Single