外文翻譯--齒輪泵工作原理.doc

齒輪泵工作原理本泵是用于機(jī)器潤滑系統(tǒng)中的輸油裝置。動(dòng)力齒輪輸入后帶動(dòng)主動(dòng)齒輪軸按逆時(shí)針方向旋轉(zhuǎn)，從而帶動(dòng)從動(dòng)齒輪軸沿順時(shí)針方向轉(zhuǎn)動(dòng)，使進(jìn)油腔形成負(fù)壓，油從進(jìn)口被吸入，經(jīng)過一對齒輪傳動(dòng)，齒槽中的油不斷沿箭頭方向被帶至左邊的出油口，送入機(jī)器中需要潤滑的部分。齒輪泵是容積式回轉(zhuǎn)泵的一種，其工作原理是：齒輪泵具有一對互相嚙合的齒輪，齒輪（主動(dòng)輪）固定在主動(dòng)軸上，齒輪泵的軸一端伸出殼外由原動(dòng)機(jī)驅(qū)動(dòng)，齒輪泵的另一個(gè)齒輪（從動(dòng)輪）裝在另一個(gè)軸上，齒輪泵的齒輪旋轉(zhuǎn)時(shí)，液體沿吸油管進(jìn)進(jìn)到吸進(jìn)空間，沿上下殼壁被兩個(gè)齒輪分別擠壓到排出空間匯合（齒與齒嚙合前），然后進(jìn)進(jìn)壓油管排出。即是由兩個(gè)齒輪、泵體與前后蓋組成兩個(gè)封閉空間，當(dāng)齒輪轉(zhuǎn)動(dòng)時(shí)，齒輪脫開側(cè)的空間的體積從小變大，形成真空，將液體吸入，齒輪嚙合側(cè)的空間的體積從大變小，而將液體擠入管路中去。吸入腔與排出腔是靠兩個(gè)齒輪的嚙合線來隔開的。齒輪泵的排出口的壓力完全取決于泵出處阻力的大小。齒輪泵的主要特點(diǎn)是結(jié)構(gòu)緊湊、體積小、重量輕、造價(jià)低。但與其他類型泵比較，有效率低、振動(dòng)大、噪音大和易磨損的缺點(diǎn)。齒輪泵適合于輸送黏稠液體。調(diào)節(jié)閥的作用是：經(jīng)調(diào)整螺釘調(diào)節(jié)彈簧的預(yù)緊力并壓緊鋼球，使出油口的油壓保持在正常工作所需的壓力，然后用螺母鎖住，當(dāng)輸油管道受阻，一旦出油口的壓力超過正常工作壓力時(shí)，則鋼球被推開，使出油口的高壓油回油池，以避免出油管道及齒輪的損壞。在泵體及泵蓋之間裝有墊片，其作用是調(diào)節(jié)齒輪端面與泵蓋之間的間隙并防止齒輪漏油！齒輪泵的概念是很簡單的，即它的最基本形式就是兩個(gè)尺寸相同的齒輪在一個(gè)緊密配合的殼體內(nèi)相互嚙合旋轉(zhuǎn)，齒輪的外徑及兩側(cè)與殼體緊密配合。來自于擠出機(jī)的物料在吸入口進(jìn)入兩個(gè)齒輪中間，并充滿這一空間，隨著齒的旋轉(zhuǎn)沿殼體運(yùn)動(dòng)，最后在兩齒嚙合時(shí)排出。在術(shù)語上講，齒輪泵也叫正排量裝置，即像一個(gè)缸筒內(nèi)的活塞，當(dāng)一個(gè)齒進(jìn)入另一個(gè)齒的流體空間時(shí)，液體就被機(jī)械性地?cái)D排出來。因?yàn)橐后w是不可壓縮的，所以液體和齒就不能在同一時(shí)間占據(jù)同一空間，這樣，液體就被排除了。由于齒的不斷嚙合，這一現(xiàn)象就連續(xù)在發(fā)生，因而也就在泵的出口提供了一個(gè)連續(xù)排除量，泵每轉(zhuǎn)一轉(zhuǎn)，排出的量是一樣的。隨著驅(qū)動(dòng)軸的不間斷地旋轉(zhuǎn)，泵也就不間斷地排出流體。泵的流量直接與泵的轉(zhuǎn)速有關(guān)。實(shí)際上，在泵內(nèi)有很少量的流體損失，這使泵的運(yùn)行效率不能達(dá)到100，因?yàn)檫@些流體被用來潤滑軸承及齒輪兩側(cè)，而泵體也絕不可能無間隙配合，故不能使流體100地從出口排出，所以少量的流體損失是必然的。然而泵還是可以良好地運(yùn)行，對大多數(shù)擠出物料來說，仍可以達(dá)到9398的效率。對于粘度或密度在工藝中有變化的流體，這種泵不會(huì)受到太多影響。如果有一個(gè)阻尼器，比如在排出口側(cè)放一個(gè)濾網(wǎng)或一個(gè)限制器，泵則會(huì)推動(dòng)流體通過它們。如果這個(gè)阻尼器在工作中變化，亦即如果濾網(wǎng)變臟、堵塞了，或限制器的背壓升高了，則泵仍將保持恒定的流量，直至達(dá)到裝置中最弱的部件的機(jī)械極限(通常裝有一個(gè)扭矩限制器)。對于一臺(tái)泵的轉(zhuǎn)速，實(shí)際上是有限制的，這主要取決于工藝流體，如果傳送的是油類，泵則能以很高的速度轉(zhuǎn)動(dòng)，但當(dāng)流體是一種高粘度的聚合物熔體時(shí)，這種限制就會(huì)大幅度降低。推動(dòng)高粘流體進(jìn)入吸入口一側(cè)的兩齒空間是非常重要的，如果這一空間沒有填充滿，則泵就不能排出準(zhǔn)確的流量，所以PV值(壓力流速)也是另外一個(gè)限制因素，而且是一個(gè)工藝變量。由于這些限制，齒輪泵制造商將提供一系列產(chǎn)品，即不同的規(guī)格及排量(每轉(zhuǎn)一周所排出的量)。這些泵將與具體的應(yīng)用工藝相配合，以使系統(tǒng)能力及價(jià)格達(dá)到最優(yōu)。TheoperationprincipleofgearpumpThepumpisusedformachinelubricationsystemoildevice.Powergearinputdrivesthedrivinggearshaftbytheanti-clockwiserotation,soastodrivethedrivengearshaftclockwiserotation,sothattheoilinletcavitytoformthenegativepressure,oilimportedfrombeinginhaled,throughapairofgears,splinesoilcontinuouslyalongthedirectionofthearrowtobebroughttotheleftoiloutlet,isfedintothemachineinneedoflubricationpart.Gearpumpisapositivedisplacementrotarypumpsonekind,itsworkingprincipleis:gearpumphasapairofmeshedgears,gear(wheel)fixedonthedrivingshaft,thegearpumpshaftextendoutofthecasingofgearpumpdrivenbyaprimemover,anothergear(wheel)mountedontheotherashaft,gearpumpgearrotates,liquidalongthesuctionpipeenterintosuckedintospace,alongtheupperandlowerwalloftheshellistwogearsarerespectivelyextrudedintothedischargespacerendezvous(toothandtoothmeshingbefore),andthenintothedischargepressuretubing.Iscomposedoftwogears,thepumpbodyandthefrontcovertwoclosedspace,whenthegearrotates,thegearsidespacevolumefromlarger,formingavacuum,liquidsuction,gearspacevolumefrombigtosmall,andtheliquidintothepipeline.Inhalationchamberanddischargechamberbytwogearsmeshinglinetoseparatethe.Gearpumpoutletpressuredependsentirelyonthepumpsourceresistancesize.Themaingearpumpischaracterizedbycompactstructure,smallvolume,lightweight,lowcost.Butwiththeothertypepumpscomparison,havealowefficiency,largevibration,noiseandeasytowear.Thegearpumpissuitableforconveyingstickyliquid.Valveistheroleof:adjustingscrewadjustingthepretighteningforceofthespringandthepressingball,outoftheoiloutletpressureismaintainedinthenormalworkofthedesiredpressure,andthenusethenutlock,whenthepipelineisblocked,oncetheoiloutletpressureexceedsthenormalworkingpressure,thenballispushedoff,outoftheoilexporthighpressureoilreturntank,oilpipelinesandtoavoidthedamageofgear.Inthepumpbodyandthepumpcoverisfittedbetweenthegasket,whoseroleistoregulateandpumpgearendcapbetweenthegapandpreventgearoil!Gearpumpconceptisverysimple,thatisitsmostbasicformistwoidenticalgearinatightlyfittingshellmeshingrotation,geardiameterandtwosidesandtheshellclosely.Fromanextrudermaterialatthesuctionportintotwogears,andfillthisspace,withthetoothrotationalongthebodymovement,theninthetwomeshingfrom.Intermsofspeaking,thegearpumpisalsocalledpositivedisplacementdevice,thatislikeacylinderpiston,whenatoothintoanothertoothfluidspace,theliquidhasbeenmechanicallypushedout.Becausethefluidisincompressible,sotheliquidandthetoothcannotatthesametimetooccupythesamespace,inthisway,theliquidhasbeenruledout.Becauseoftheconstantmeshgear,thisphenomenonoccursonarow,andalsoattheoutletofthepumpprovidesacontinuousexcludedvolume,aturneachpump,thevolumeofdischargeisthesame.Alongwiththecontinuousrotationofthedriveshaft,pumpfluidiscontinuouslydischarged.Pumpflowdirectlytothespeedofthepump.Infact,thepumphasasmallamountoffluidloss,whichmakestheoperationofthepumpefficiencycanreach100%,becausethefluidisusedtolubricatethebearingandgearonbothsides,andthepumpbodywillneverbewithoutclearance,soasnottoallowfluidto100%isdischargedfromtheoutlet,soasmallamountoffluidlossisinevitable.Howevergoodpumpcanberun,outofmaterialforthemajority,stillcanreach93%98%efficiency.Fortheviscosityordensitychangeintheprocessoffluid,thepumpwillnotbeaffectedtoomuch.Ifthereisadamper,forexampleontheoutletsideofafilterandalimiter,thepumpwillpushfluidthroughthem.Ifthedamperinthejobchanges,i.e.ifthefilterisdirty,blocked,orlimiterpressureincreased,thepumpwillcontinuetomaintainaconstantflowdevice,untilitreachestheweakestpartsmechanicallimit(usuallywithatorquelimiter).Forapumpspeed,thereisavirtuallimit,whichdependsmainlyontheprocessfluid,ifthetransmissionisoil,pumpcanrotateathighspeed,butwhenthefluidisahighviscosityofthepolymermelt,suchrestrictionswillbegreatlyreduced.Promotebloodflowintotheintakesideofthetwotoothspaceisveryimportant,ifnotfillinthisspaceisfull,thepumpwillnotbeabletodischargetheflowofaccurate,sothevalueofPV(pressurexvelocity)isalimitingfactor,but