《水處理技術(shù)（雙語）》課件-螺桿泵

Screwpumps螺桿泵螺桿泵（上）Screwpumps(I)螺桿泵在發(fā)達(dá)國家已廣泛使用，國外多數(shù)稱單螺桿泵為“莫諾泵”，德國稱為“偏心轉(zhuǎn)子泵”。Screwpumpshavebeenwidelyusedindevelopedcountries,mostforeigncountriescalledtheprogressivecavitypump"Monopump",Germanyiscalled"eccentricrotorpump".由于其優(yōu)良的性能，近年來在國內(nèi)的應(yīng)用范圍也在迅速擴大。它的最大特點是對介質(zhì)的適應(yīng)性強、流量平穩(wěn)、壓力脈動動小、自吸能力高，這是其它任何泵種所不能替代的。Duetoitsexcellentperformance,theapplicationrangeinChinaisalsoexpandingrapidlyinrecentyears.Itsbiggestfeaturesarestrongadaptabilitytothemedium,smoothflow,smallpressurepulsationandhighself-primingcapacity,whichcannotbereplacedbyanyotherpumptypes.螺桿泵的分類Classificationofscrewpumps（一）按螺桿數(shù)目分Bynumberofscrews1、單螺桿泵---單螺桿泵在泵體的內(nèi)螺紋槽中嚙合轉(zhuǎn)動的泵。Singlescrewpump-Apumpinwhichasinglescrewpumpengagesandrotatesinagrooveintheinternalthreadofthepumpbody.2、雙螺桿泵---由兩個螺桿相互嚙合輸送液體的泵。

Twin-screwpump-apumpthatconsistsoftwoscrewsmeshingwitheachothertotransportliquid.3、多螺桿泵---由多個螺桿相互嚙合輸送液體的泵。Multi-screwpump-apumpthatconsistsofmultiplescrewsmeshingwitheachothertotransportliquid.圖為雙螺桿泵工作原理Workingprincipleoftwinscrewpump圖為單螺桿泵工作原理Singlescrewpumpworkingprinciple圖為多螺桿泵工作原理Multi-screwpumpworkingprinciple螺桿泵的分類Classificationofscrewpumps（二）按螺桿吸入方式分Byscrewinhalationmethod1、單吸式：油料從螺桿一端吸入，從另一端排出。Singlesuctiontype:Oilisdrawninfromoneendofthescrewanddischargedfromtheotherend.2、雙吸式：油料從螺桿兩端吸入，從中間排出。

Doublesuctiontype:Oilisdrawninfrombothendsofthescrewanddischargedfromthemiddle.圖為單吸式螺桿泵Single-suctionscrewpumps圖為雙吸式螺桿泵Double-suctionscrewpumps螺桿泵的分類Classificationofscrewpumps單吸式和雙吸式螺桿泵在油庫中均有采用。Bothsingle-suctionanddouble-suctionscrewpumpsareusedinoildepots.按泵軸位置還可以分為臥式泵和立式泵。Itcanalsobedividedintohorizontalandverticalpumpsaccordingtothelocationofthepumpshaft.油庫中常用的是臥式泵。Horizontalpumpsarecommonlyusedinoildepots.圖為臥式泵Horizontalpumps圖為立式泵VerticalPumps螺桿泵的分類Classificationofscrewpumps本節(jié)微課以目前市場最常用的單螺桿泵為例進行講解Thismicro-lessonisanexampleofthemostcommonprogressivecavitypumpsinthemarkettoday單螺桿泵結(jié)構(gòu)及工作原理結(jié)構(gòu)Singlescrewpumpstructureandworkingprinciplestructure圖為G型單螺桿泵的結(jié)構(gòu)圖StructurediagramofGtypesinglescrewpump如圖所示：1出料口2拉桿3定子4螺桿軸5萬向節(jié)總成6吸入口7連節(jié)軸8填料座9填料壓蓋10軸承座11軸承蓋12電動機13連軸器14軸套15軸承16傳動軸17底座Asshowninthefigure:1outlet2tierod3stator4screwshaft5universaljointassembly6suctionport7jointedshaft8packingseat9packinggland10bearingseat11bearingcover12motor13shaftcoupling14bushing15bearing16driveshaft17base螺桿泵的三個主要特征尺寸Thethreemaincharacteristicdimensionsofthescrewpump定子導(dǎo)程T(mm)：轉(zhuǎn)子螺距的兩倍StatorleadT(mm):twicetherotorpitch偏心距：e(mm)Eccentricdistance:e(mm)轉(zhuǎn)子截面直徑：D(mm)Rotorcross-sectiondiameter:D(mm)偏心率的大小直接影響到泵的性能、效率和壽命，還直接決定離心力的大小，從而影響到泵的振動、噪聲，甚至橡膠定子的磨損等。Thesizeoftheeccentricitydirectlyaffectstheperformance,efficiencyandlifeofthepump,andalsodirectlydeterminesthesizeofthecentrifugalforce,whichaffectsthevibration,noise,andeventhewearoftherubberstator.偏心越小則泵的流量也越小，但泵的運行月穩(wěn)定，壽命越長。Thesmallertheeccentricity,thesmallertheflowofthepump,butthemorestabletheoperationofthepump,thelongerthelife.離心泵的工作原理Theworkingprincipleofcentrifugalpump導(dǎo)程越大，則流量越大，但泵的長度尺寸也增大，而且使介質(zhì)的軸流速度變大，直接影響泵的吸上能力。Thelargerthelead,thelargertheflow,butthelengthofthepumpsizealsoincreases,andtheaxialvelocityofthemediumbecomeslarger,whichdirectlyaffectsthesuctioncapacityofthepump.因此，選擇恰當(dāng)?shù)膃/D和T/D值是非常重要的。Therefore,itisveryimportanttochoosethepropere/DandT/Dvalues.采用大螺距、大偏心還是采用小螺距，小偏心應(yīng)考慮到泵的性能參數(shù)、轉(zhuǎn)子結(jié)構(gòu)、使用情況和介質(zhì)等多個因素。Theuseoflargepitch,largeeccentricityortheuseofsmallpitch,smalleccentricityshouldtakeintoaccounttheperformanceparametersofthepump,rotorstructure,useandmediaandmanyotherfactors.單螺桿泵的工作原理Theworkingprincipleofsinglescrewpump單螺桿泵是按回轉(zhuǎn)嚙合容積式原理工作的新型泵種。Theprogressivecavitypumpisanewtypeofpumpthatworksaccordingtotheprincipleofrotarymeshingdisplacement.主要工作部件是偏心螺桿（轉(zhuǎn)子）和固定的襯套（定子）。Themainworkingpartsaretheeccentricscrew(rotor)andthefixedbushing(stator).由于該部件的特殊幾何形狀分別形成單獨的密封容腔。Duetothespecialgeometryofthecomponentseparatesealingcavitiesareformed.單頭陽螺旋轉(zhuǎn)子在特殊的雙頭陰螺旋定子內(nèi)偏心地轉(zhuǎn)動（定子是柔軟的），能沿泵中心線來回擺動，與定子始終保持嚙合，介質(zhì)由軸向均勻推行流動。Thesingle-headedmalespiralrotorrotateseccentricallyinaspecialdouble-headedfemalespiralstator(thestatorisflexible),whichcanswingbackandforthalongthepumpcenterline,alwaysengagingwiththestator,andthemediumflowsuniformlyfromtheaxialpush.單螺桿泵結(jié)構(gòu)及工作原理結(jié)構(gòu)Singlescrewpumpstructureandworkingprinciplestructure圖為G型單螺桿泵的結(jié)構(gòu)圖1出料口2拉桿3定子4螺桿軸5萬向節(jié)總成6吸入口7連節(jié)軸8填料座9填料壓蓋10軸承座11軸承蓋12電動機13連軸器14軸套15軸承16傳動軸17底座內(nèi)部流速低，容積保持不變，壓力穩(wěn)定,因而不會產(chǎn)生渦流和攪動。Theinternalflowrateislow,thevolumeremainsconstant,andthepressureisstable,thusnovortexorchurningisgenerated.單螺桿泵被廣泛用于各行業(yè)輸送各類介質(zhì)，恒壓連續(xù)運行，無脈動，介質(zhì)輸送無破損，通過調(diào)節(jié)轉(zhuǎn)速改變流量從而達(dá)到計量的目的。Singlescrewpumpiswidelyusedinvariousindustriestotransportallkindsofmedia,constantpressurecontinuousoperation,nopulsation,mediadeliverywithoutbreakage,changetheflowratebyadjustingthespeedtoachievethepurposeofmetering.單螺桿泵性能參數(shù)Singlescrewpumpperformanceparameters單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors單螺桿泵性能參數(shù)通常指流量、排出壓力、吸入壓力、轉(zhuǎn)速、泵輸入功率（軸功率）、介質(zhì)特性、介質(zhì)溫度和介質(zhì)的粘度等。Singlescrewpumpperformanceparametersusuallyrefertotheflowrate,dischargepressure,suctionpressure,speed,pumpinputpower(shaftpower),mediacharacteristics,mediatemperatureandviscosityofthemedia.流量受轉(zhuǎn)速和介質(zhì)粘度的影響，介質(zhì)粘度也影響泵的輸入功率，轉(zhuǎn)速的選擇與介質(zhì)粘度有很大關(guān)系，還影響到泵的吸入性能等。Flowrateisaffectedbythespeedandmediumviscosity,mediumviscosityalsoaffectstheinputpowerofthepump,thechoiceofspeedandmediumviscosityhasagreatrelationship,butalsoaffectthesuctionperformanceofthepump,etc.設(shè)計泵時必須考慮這些參數(shù)之間的關(guān)系。Therelationshipbetweentheseparametersmustbeconsideredwhendesigningthepump.

流量Flow泵輸入功率（軸功率）Pumpinputpower(shaftpower)排出壓力Dischargepressure吸入壓力Inhalationpressure轉(zhuǎn)速RotationalSpeed介質(zhì)特性MediaProperties介質(zhì)溫度Mediatemperature介質(zhì)Media單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors（一）流量（Flow）流量是指泵在單位時間內(nèi)輸送的介質(zhì)量或是泵每一轉(zhuǎn)所排除的介質(zhì)量。Flowratereferstotheamountofmediadeliveredbythepumpinaunitoftimeortheamountofmediaremovedbythepumpateachrevolution.體積流量用Q表示，質(zhì)量流量用Qz表示。質(zhì)量流量和體積流量的關(guān)系為：ThevolumetricflowrateisdenotedbyQandthemassflowrateisdenotedbyQz.Therelationshipbetweenmassflowrateandvolumeflowrateis圖為污泥螺桿泵型號規(guī)格及參數(shù)Sludgescrewpumpmodelspecificationsandparameters單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors式中ρ——介質(zhì)密度（Mediumdensity）（㎏/m3）。當(dāng)轉(zhuǎn)子轉(zhuǎn)動一周，介質(zhì)沿著軸向移動定子一個導(dǎo)程T，故轉(zhuǎn)子轉(zhuǎn)動一周，輸送的介質(zhì)體積為4eDT。Whereρ--mediumdensity(Mediumdensity)(㎏/m3).Whentherotorisrotatedonce,themediummovesthestatoralongtheaxialdirectionforoneleadT.Therefore,therotorisrotatedonce,andthevolumeofthemediumconveyedis4eDT.所以當(dāng)轉(zhuǎn)子轉(zhuǎn)速為n時，單螺桿泵每秒的理論流量Q1為：

Sowhentherotorspeedisn,thetheoreticalflowratepersecondoftheprogressivecavitypumpQ1is:單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors實際上橡膠定子與轉(zhuǎn)子的配合有過盈量，這必然會造成定子橡膠的變形。Infact,therubberstatorfitstherotorwithasurplus,whichinevitablycausesdeformationofthestatorrubber.因此，實際的理論流量要比如圖所示計算的理論流量要小些。Therefore,theactualtheoreticalflowrateissmallerthanthetheoreticalflowratecalculatedasshowninthefigure.若要得到精確的實際理論流量值，可把轉(zhuǎn)子裝入定子后，截下長度為T的一段，對其注滿水，再測量出注入水的體積。Togetanaccurateactualtheoreticalflowvalue,therotorcanbeloadedintothestator,cutoffasectionoflengthT,fillitwithwater,andthenmeasurethevolumeofwaterinjected.單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors泵的實際流量Q低于實際的理論流量Q1，這是由于定子和轉(zhuǎn)子之間的配合實際如前面所述在運行時總會有些介質(zhì)在排除壓力作用下通過不密封的配合間隙流回到吸入腔。

TheactualflowrateofthepumpQislowerthantheactualtheoreticalflowrateQ1,becausetheactualfitbetweenthestatorandrotorasdescribedabovewillalwayshavesomemediumflowingbackintothesuctionchamberthroughtheunsealedfitgapunderexclusionpressureduringoperation.間隙越大，泄漏越多，密封腔兩端的壓力差越大，泄漏量也越大。Thelargerthegap,themoreleakage,andthegreaterthepressuredifferencebetweenthetwoendsofthesealingchamber,thegreatertheleakage.此外，介質(zhì)輸送過程中夾雜氣體，也會造成流量降低。Inaddition,theentrainmentofgasinthemediaconveyingprocesswillalsocausetheflowratetodecrease.單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors（二）全壓力Fullpressure

這里所說的全壓力p即泵的壓力差，是指排出壓力pd和吸入壓力ps之差。

Herethefullpressurepisthepumppressuredifference,referstothedischargepressurepdandthedifferencebetweenthesuctionpressureps.圖為容積式泵Volumetricpumps單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors對于容積式泵來說，所謂的排出壓力實際上就是泵的背壓，也就是泵出口管路系統(tǒng)總的阻力，這是與離心式水泵概念完全不同的。所以單螺桿泵的壓力差是與輸送介質(zhì)的性質(zhì)無關(guān)；Forpositivedisplacementpumps,theso-calleddischargepressureisactuallythebackpressureofthepump,thatis,thetotalresistanceofthepumpoutletpipingsystem,whichiscompletelydifferentfromtheconceptofcentrifugalpumps.Sothepressuredifferenceoftheprogressivecavitypumpisnotrelatedtothenatureofthetransportmedium.需要注意的是輸送的介質(zhì)粘度越大，其在出口管路系統(tǒng)中的阻力也越大。

Itshouldbenotedthatthegreatertheviscosityoftheconveyedmedium,thegreatertheresistanceintheoutletpipingsystem.單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors（三）轉(zhuǎn)速RotationalSpeed單螺桿泵可靠地工作必須限制轉(zhuǎn)速。Aprogressivecavitypumpmustworkreliablybylimitingthespeedofrotation.影響選擇轉(zhuǎn)速的主要因素如下：Themainfactorsaffectingthechoiceofspeedareasfollows.1、吸入性能（Inhalationperformance）。

圖為單螺桿泵固定轉(zhuǎn)速時的性能參數(shù)Performanceparametersofsinglescrewpumpatfixedspeed單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors泵的轉(zhuǎn)速越高，其流量也越大，轉(zhuǎn)速不僅影響到泵吸入腔中的損失，而且當(dāng)轉(zhuǎn)速提高到一定程度，就會發(fā)生在吸入壓力作用下的介質(zhì)來不及進入或來不及充滿打開的密封腔，使之出現(xiàn)某種程度的真空狀態(tài)，輸送介質(zhì)就會大量析出所溶解的氣體，以氣泡形式分布在介質(zhì)中，成為乳濁液，導(dǎo)致流量減少，甚至使泵不能正常工作。如果壓力降到與一定溫度下被輸送介質(zhì)的飽和蒸汽壓力時泵內(nèi)就會出現(xiàn)汽蝕現(xiàn)象。因此，轉(zhuǎn)速受到吸入條件的限制。一般泵的轉(zhuǎn)速越低，即介質(zhì)的軸向流速越小，泵的吸入性能就越好。介質(zhì)粘度越高，泵的吸入性能越差。介質(zhì)的溫度直接影響到介質(zhì)的飽和蒸汽壓力和某些介質(zhì)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.我國標(biāo)準(zhǔn)JB/T8644-1997《單螺桿泵型式與基本參數(shù)》編制時介質(zhì)的軸向流速取不大于4~4.5m/s。China'sstandardJB/T8644-1997"singlescrewpumptypeandbasicparameters"whenthepreparationoftheaxialflowrateofthemediumisnotgreaterthan4~4.5m/s.單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors2、粘度（Viscosity）。當(dāng)介質(zhì)的粘度增大時，不僅會使在吸入壓力作用下介質(zhì)進入密封腔因阻力增大而更為困難，而且使轉(zhuǎn)子對介質(zhì)的剪切作用所產(chǎn)生的機械損失也增加。因此單螺桿泵運行時，若介質(zhì)的粘度越大，則應(yīng)選擇越大的轉(zhuǎn)速。Whentheviscosityofthemediumincreases,itwillnotonlymakeitmoredifficultforthemediumtoenterthesealingcavityundertheactionofsuctionpressureduetotheincreaseofresistance,butalsoincreasethemechanicallosscausedbytheshearactionoftherotoronthemedium.Therefore,whenthesinglescrewpumpisrunning,thehighertheviscosityofthemedium,thehigherthespeedshouldbeselected.圖為常見介質(zhì)的粘度表Viscositytableofcommonmedia單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors3、介質(zhì)的磨損性。Abrasivenessofthemedium.介質(zhì)的磨損性直接影響到轉(zhuǎn)子和定子的耐磨程度，即影響到使用壽命。介質(zhì)越“惡劣”（此處僅指所含的雜志、潤滑性和流動性等），轉(zhuǎn)子和定子必然越容易磨損，而且泵的轉(zhuǎn)速越高，磨損就越快。Theabrasivenessofthemediumdirectlyaffectsthewearresistanceoftherotorandstator,i.e.,affectstheservicelife.The"harsher"themedium(hereonlyreferstothemagazine,lubricityandfluidity,etc.),themoreeasilytherotorandstatorareboundtowear,andthehigherthepumpspeed,thefasterthewear.單螺桿泵性能參數(shù)及其影響因素Singlescrewpumpperformanceparametersandtheirinfluencingfactors4、介質(zhì)為乳膠狀液體時其結(jié)構(gòu)對轉(zhuǎn)速的敏感程度。

Thesensitivityofthestructuretorotationalspeedwhenthemediumisanemulsionliquid.如前面所述泵輸送介質(zhì)是為了從油污水中分離油時，要求不使介質(zhì)乳化加劇，必須要求泵低速運行，通常轉(zhuǎn)速不超過200r/min。Asmentionedearlierthepumpconveysthemediuminordertoseparatetheoilfromtheoilywater,therequirementsdonotmakethemediumemulsificationintensified,thepumpmustberequiredtorunatlowspeed,usuallythespeeddoesnotexceed200r/min.單螺桿泵特點及應(yīng)用Singlescrewpumpfeaturesandapplications單螺桿泵因定子選用多種彈性材料制成，所以這種泵對高粘度達(dá)到80%流體的輸送和含有硬質(zhì)懸浮顆粒介質(zhì)或含有纖維介質(zhì)的輸送，有一般泵種所不能勝任的特性。

Single