vacuum-pump(真空泵)

UnitⅡ.VacuumPumps05/10/2004Title2Vacuumpumps•beconcernedwith与…相关•pumpingmechanism:loweringthemoleculesnumber•compression-expansion:pistonpump（活塞）liquidringpump（液环）rotarypumpRoot’spump•Dragbyviscosity(黏性）:vaporejectingpump•Dragbydiffusioneffect:vapordiffusionpump•moleculardrag:molecularpump•ionizationeffect:ionpump•physical/chemicalsorptionpump:sorptionpump,cryopump(低温）,gettering(吸气）pump2.1Principlesofpumping05/10/2004Title3AsortofpumpI.Gastransferpumpsremovegasparticlesfromthesystem.Therearerotaryvanepump,turbomolecularpumpanddiffusionpumpingastransferpumps.II.Entrapmentpumpsinwhichgasparticlesthathaveenteredfromthesystemaretrappedeitherchemicallyorphysicallywithinthepump.Therearesputterionpump,sublimationpumpandsorptionpumpinentrapmentpumps.Vacuumpumpscanbeclassifiedaseithergastransferpumpsorentrapmentpumps,accordingtotheiroverallpumpingmechanism.05/10/2004Title4VACUUMPUMPINGMETHODSSlidingVaneRotaryPumpMolecularDragPumpTurbomolecularPumpFluidEntrainmentPumpVACUUMPUMPS(METHODS)ReciprocatingDisplacementPumpGasTransferVacuumPumpDragPumpEntrapmentVacuumPumpPositiveDisplacementVacuumPumpKineticVacuumPumpRotaryPumpDiaphragmPumpPistonPumpLiquidRingPumpRotaryPistonPumpRotaryPlungerPumpRootsPumpMultipleVaneRotaryPumpDryPumpAdsorptionPumpCryopumpGetterPumpGetterIonPumpSputterIonPumpEvaporationIonPumpBulkGetterPumpColdTrapIonTransferPumpGaseousRingPumpTurbinePumpAxialFlowPumpRadialFlowPumpEjectorPumpLiquidJetPumpGasJetPumpVaporJetPumpDiffusionPumpDiffusionEjectorPumpSelfPurifyingDiffusionPumpFractionatingDiffusionPumpCondenserSublimationPump05/10/2004Title5PUMPOPERATINGRANGES10-1210-1010-810-610-410-2110+2P(mbar)RoughVacuumHighVacuumUltraHighVacuumVenturiPumpRotaryVaneMechanicalPumpRotaryPistonMechanicalPumpSorptionPumpDryMechanicalPumpBlower/BoosterPumpHighVac.PumpsUltra-HighVac.Pumps05/10/2004Title62.2parameterandclassification•ultimatepressurelowestpressureatitsinletleakagevapourpressure•pressurerange(usefulpumpingaction)adjacent相近的•pumpingspeed(functionofpressure)Thepumpingspeedisthevolumetricflowthroughthepump’sintakeport.•specific•exhaustpressure•selectivity抽气选择性•compositionoftheresidualgas•frommypointofview(viewpoint)inmyopinion•roughingpump:pumpingtoacceptableoperatingpressure•backingpump:maintanceofrequiredlowpressureattheoutletofanotherpump•outlet/inlet•operatingpump:启动压强•sub-:submicron,subsidiarycompany，subsequent•immobilize固定不动mobilephone•ionization电离sorption吸附05/10/2004Title7PumpingSpeed10-1010--310--1PumpingSpeed(Air)1234InletPressure(Torr)CriticalPoint1.CompressionRatioLimit2.ConstantSpeed3.ConstantQ(Overload)4.MechanicalPumpEffect05/10/2004Title8SelectivityMolecularpumpSorptionpump05/10/2004Title9RotaryvanepumpOilsealedrotaryvanepumpsaresuitableforthedirectproductionofroughandmediumvacuum.Theyarealsousedextensivelytobackrootsvacuum,turbomolecularanddiffusionpumps.FourstagesinthecycleofarotaryvanepumpThemechanism,whichislubricatedbyoil,consistsofahousingwithacylindricalboreintowhichisfittedarotor.Therotorturns,thetipsofthebladesareincontactwiththestatorwallatalltimes.Fourstagesinonerevolutionoftherotorareinduction,isolation,compressionandexhaustphases.05/10/2004Title10Mineraloilsarethemostcommonlyusedfluidsforrotarypumps.Ingeneral,oilsavailablefromagarageservicestationorstoredonothaveasuitablelowvapourpressureandnoneexhibittheservicelifeorlowlevelofbackmigrationrequiredformostprocess.Mineraloilsofferedbyvacuumpumpmanufacturesandothersuppliershavebeendistilledtoremovevolatilecomponents.ThecrosssectionofrotaryvanepumpSchematicofarotaryvanepumpRotaryvanepump05/10/2004Title11CrosssectionofrotarypumpImageofrotarypumpandpartsRotaryvanepump05/10/2004Title1205/10/2004Title13Twostagerotarypump05/10/2004Title14•constitute组成•statorn.定子,固定片•eccentricrotorn.偏心转子•vane/blade：阀片•diametral•slotn.缝,狭槽•cylinder•tubulationn.管•dustfilter滤网•arresterplate:锁定平板•sheetofneoprenen.丁晴橡胶垫（条）•hinge铰链•backingsleet挡板•drivingshaft驱动轴•clearance间隙•slidingfit:滑动配合•spring弹簧rotating-vanepump/rotarypump05/10/2004Title15•roundedend•submerge•topseal顶端密封•exhaustvalve排气阀•intake吸入量cavity空腔•volumerate•pumpdisplacement:排气量•abrasivematerial:腐蚀性材料•deadvolume:余隙容积，有害空间•re-又，再•discharge排出compressionratio:压缩比themainfunctionoftheoil:lubricationsealingfillingthedeadvolumepermanentgastotal/partialgasMcleod/piranigaugereading读数Parallel/seriesconnection并/串连deadvolume05/10/2004Title16•Pumpingspeedcurves•falloff下降•noticeableobvious•gasballast气镇•condensibleadj.可压缩(凝缩)的•contaminatevt.污染•evaporate---condense05/10/2004Title17Gasballast1)Pumpisconnectedtothevessel,whichisalreadyalmostemptyofair(70mbar)–itmustthustransportmostlyvaporparticles2)Pumpchamberisseparatedfromthevessel–compressionbegins3)Contentofpumpchamberisalreadysofarcompressedthatthevaporcondensestoformdroplets–overpressureisnotyetReached4)Residualaironlynowproducestherequiredoverpressureandopensthedischargevalve,butthevaporhasalreadycondensedandthedropletsareprecipitatedinthepump.Withoutgasballast05/10/2004Title18Gasballast1)Pumpisconnectedtothevessel,whichisalreadyalmostemptyofair(70mbar)–itmu