文献翻译-反应釜用机械密封设计

第1页共9页附录原文：MechanicalSealDesignReactorInstituteofElectricalandMechanicalDepartmentofGeneralChenI.IntroductionAgitatedreactorischemical,pharmaceuticalproductioninoneofthekeyequipment,itsoperatingefficiencyandreliabilityofthedevicedependslargelyonthemeritsofparticularsealhigh-pressurehigh-temperaturereactorshaftsealiscurrentlytheneedforspecializedsolutionsproblem.Chinahasbeensettingthestandardkettle-typemechanicalsealproducts,201,202,203,204,205,206,theuseofpressure116kgf/cm,shaftdiameteris30ll0mm.Inrecentyears,withthepetrochemical,pharmaceuticalindustry,stirredtankreactorreactionpressure,temperaturegraduallyelevated,andthedirectiontowardsthedevelopmentofhighperformance.Pollutionpreventionandsafetyfromboth,energyconservationpointofviewofthesealdevicereliability,longevity,leakageQuantityandeconomyandotherrequirementsarealsoincreasing.Therefore,theexistingstandardkettlewithmechanicalsealscannotfullymeettheirrequirements,uptotheneedtousespeciallydesignedworkingconditions.Inthispaper,ahightemperatureautoclavedesignofmechanicalsealforabriefintroduction.Second,theconditionsgivenbytheuserDevice:300literverticalreactor,stirringshaftinsertedfromthetop,single-bearing;Maximumworkingpressure;25kgf/cm;Temperature:roomtemperature15OStirringspeed:12O150rpm;Medium:diluteammonia+dehydroacetatepowder+solventBiochemistry;Shaftdiameter:30mm,diameterlengthratio:1:50;Axialspace:Kamaguchicouplingflangetothebacksidewhiletheheightisabout293mm;Operation:Intermittentoperation,stoppingfrequentlytoopen;Leakage:3ml/h;Life:8000h(oneyear).Third,technicalanalysisanddesignAccordingtotheconditionsandrequirementsofagivenpointofview,themechanicalsealisaveryharshoperatingconditions.Themainproblemsinvolved:1.Toploadingautoclavetechnicalproblemswiththenatureofthemechanicalsealpumpmechanicalsealcompletelydifferent,becauseitisinthevaporspace(onlythematerialisliquidwhenthetankisfull),sealpronetodryrun.2.Asthemediumisthechemicalreactionwithinthereactor,pressure,temperature,materialandshapechangearealwaysasked,inthestresscycleandtheroleofthermalcycles,thesealfacesdeformeasily.3.Mechanicalsealusedatroomtemperature,duetothefrictionsurfaceoftheheatingandsealingofthemixingheatwillsealtheroomtemperaturerise.Whenusedathightemperatures,duetoheatconductionwithinthetank,thetemperaturewillfurtherrise,causingfrictionsurfaceoftheliquidfilmevaporation,resultingindryrun,andtopromotecorrosion,acceleratedagingauxiliaryring,resultingindeteriorationintheshorttermsealingperformance.4.Stirringshaftinsertedfromthetopverticalreactor,itsdiameterlongerthanlarge.Itisasinglesupport,theamountofitsinevitableswinghigher.5.Inthereactionprocess,themixerbladesandfluidmaterialgeneratedbyrelativemotionbetweenthevortex,mustbecausedbymixingshaftvibration.6.Mayalsooccurforthefollowingreasonsaxistraverse:(1)unevenorliquidfeedistoolow;(2)formationdidnotcontrolthereactants,viscosityincreases;(3)suddenchangesinspeedmixer;(4)thermalexpansionorpressureandtemperaturefluctuate.7.Becausethetopofthereactorveryeasytoinstallseal.Kettlemechanicalsealinthestructuremustbeeasytoinstallandremoval.Inthepast,mechanicalsealfailureresultinginperformance,manyofthemarecausedbypoorinstallationofthereactorbecausetheexistingpartsofmechanicalsealtothereactorneedtoinstallonebyone,weshouldensurethatitsaccuracyisdifficult.Accordingtotheconditionsgivenbytheuserandthetechnicalanalysistodeterminethefollowingbasicdesign:1.Higheruseofsafetybarrierdoubleendmechanicalseal,toensurethereactorsealed.2.Sealedfromtheoutsidetoenterthecleanroomsuitableforthelubricationofcoolingliquidresistancesealed,andsetthecoolingwaterjacket,toimprovethesealingoftheoperatingconditions3.Thestructureofthesealingdevice,additionalbearingstoreduceshaftdeflectionandarockyledge.4.Considertheeaseofinstallationandremoval,andeconomicfactors.4,structuraldesignfeaturesAccordingtothedesignofmechanicalsealdesign,thefrictionpairmaterialforthesurfacingalloycarbonGraphite,supportingringmaterial:NBRa4O.Specifictechnicalmeasures;1.Considerthepressurefluctuationsinthedesignofthesealby30kgf/cm.Sidesealingsurfaceoftheupperatmosphericpressuretobearlarge,sodesignedasbalanced,30%,staticmethodsupportsdual-ringseal0-ringtoreducethestaticpartofthedeformation.Mediumwithinthelowerpartofthelateralsideofthesealingsurfacepressureissmall,itisdesignedtobenon-balanced.Itisworthnotingthatthissideofthesealmayseemeasy,infact,not.Ifnothandledproperlycauseleaks,pollutionvesselwillbewithinthematerial,resultinginproductfailure,wemustgiveourfullattention.Understaticcompressionringdoesnotusethetraditionalstructure,butwithgooduseofthefollowingfloating-mountedsothattheendisalwaysthebestfittomaintainthestate.2.Installationofashorteraxialdimensionstructure,becausethesealandspringseatsharingadrive.Withasleeveonthekeywayandfixingscrewtodrivethedriveseat,sturdyandreliable3.Thestructureofthesealbearingaddedtoimprovethedynamicstabilityofthemixingshaft(measuredatthetankflangerunoutoftheshaft0.05mm).Mechanicalsealfromthebearingmountedclosetotheplace,thusenhancingthesealingoperationstability.4.Officesinthesealedchambercoolingwaterjackettoreduceheatfromthereactorbodytopasschamber.5.Introducedtothesealedchamberfromanexternalsealingliquid,onthemechanicalseallubrication,coolingandblockletters.6.Thesealstructurehasafastandaccurateinstallationandremovalofbenefits.Thesealasanintegratedwhole,canbepre-assembled,andtested,andthenloadedontothekettle,donotneedtore-adjust.Ifthesealfails,theentiresealcanberemoved,thepre-assembly,debuggingcanbeagoodbackupsealfitted.Therefore,theinstallation,maintenanceandreplacementisveryconvenient,stoppingatthesametimegreatlyreducingthetime,withobviouseconomicBenefits.5,sealingliquidsystemForthereactorwithdoublemechanicalseal,thesealingperformanceandstabilitytomakelongworkinglife,thekeyistousepropersealingliquidsystem.Onthebasicrequirementsofsealingliquidsystemistoensurethesafeoperationofseal,namely:1.Underacertainpressure,tosendthesealonthesealingliquidtomaintaintheliquidfilmbetweenthefrictionsurfaceandformabarrierbetweenthematerialandtheatmospheretoensurethatmaterialsnotleakfluid.2.Closedloopliquidcirculationshouldbesufficienttotakeawaytheheatgeneratedbyfrictionsurfaceandbystirringshaftorcontainertoavoidtheconductionofheattothesealingdevice.3.EnsurethattheKettleisalwaysinproperoperatingcondition.Thedesignofthesealingliquidpressurecontrolsystemusesbothmethods,thatis,thetoppickoutofakettlebody1-inchpipelinetoapressuretanktop.Pressuretankinstalledinthesealedroomabovethe2mDepartment.Sealingliquidsealchamberexitatthehighestpointofthewaterjacket,thermalsiphoneffecttoachievethepurposeofthecoolingcycle.Thevolumeofpressuretank2Oliters,madeofstainlesssteel.Theperipheralcoolingjacket,heattransferareaof0.02squaremeters,topreventthesealingliquidtemperatureoxidationanddeterioration.Pressuretanktothehighestpressure30kgf/c.Setobituary.Attachmentsareusedinpressuregauge,liquidlevelmeter,andthermometers,exhaustvalveanddrainvalve,liquidfillingthemouthandsoon.Sealingliquidwithdiluteglycerol(glycerin,andsoftwaterof50%),onceeverythreemonthstoreplace.Becausethesystemusesthermalsiphonmethod,asimpleeconomy,thepressurechangesinsidethereactortofollow,andcanensurethatthesealfluidpressurewithinthepressureslightlyhigherthanthekettle.VIConclusionChemical,pharmaceuticalproductioninstirredtankreactor,theleakagedemanding.Ifexcessiveleakagewillresultinproductfailureorshutdown,sotheneedforeffectiveandreliablesealdevice.Practiceshowsthatthemechanicalsealtomeettheirrequirements.ThisarticledescribesthereactionvesselwithamechanicalsealforachemicalplantinAnhuidesign.Sincetheon-siteinstallationofthesealafterthesealingperformanceandstability,leakageisextremelysmall,lifenearlytwoyears,stillcontinuetouse.反应釜用机械密封设计机电部通用机械研究所陈德才一、前言搅拌式反应釜是化工、制药生产中的关键设备之一，其运行效率和可靠性很大程度上取决于轴封装置的优劣尤其是高压高温反应釜的轴封是当前需要专门解决的问题。国内已定型的标准型釜用机械密封产品有201、202、203、204，205、206型，其使用压力为116kgfcm，轴径为30ll0mm。近年来，随着石化、制药工业的发展，搅拌反应釜的反应压力、温度随之增高，并向着高性能方向发展。同时从防止污染以及安全、节能等角度出发，对轴封装置的可靠性、寿命、泄漏量和经济性等方面的要求也越来越高。因此，现有的标准型釜用机械密封产品已不能完全满足其要求，达就需要根据使用工况进行专门设计。本文就一种高温高压反应釜用机械密封的设计作一概要的介绍。二、用户给定条件装置：300立升立式反应釜，搅拌轴从顶部插人，单支承；最高工作压力；25kgfcm；温度：室温15O搅拌速度：12O150rpm;介质：稀氨水+脱氢醋酸粉料+生物化学溶剂；轴径：30mm，径长比：1：50；轴向空间:釜口法兰至联轴节背端而高度约为293mm;操作方式：间歇操作，开停频繁;泄漏量:3mlh;寿命:8000h(一年)。三、技术分析和设计思想根据给定的条件和要求来看，该机械密封的运转条件是相当恶劣的。所涉及的主要问题是:1顶装釜用机械密封的技术问题性质完全不同于泵用机械密封，因为它是处于气相空间中(只有物料为满釜时才是液相)，密封易出现“干运转”。2由于介质是在釜内进行化学反应，压力、温度、物料的形态等都是随时问而变化的，在压力循环和冷热循环的作用下，密封端面易产生变形。3.机械密封在常温下使用时，由于摩擦面的发热和密封的搅拌生热会使密封室内温度上升。在高温使用时，由于釜内的热传导，将使温度进一步上升，从而引起摩擦面的液膜汽化，产生“干运转”，并促进腐蚀，加速辅助密封圈老化，致使密封性能在短期内恶化。4搅拌轴从顶部插人立式反应釜，其径长比大又是单支承，其摆动量必然较大。5在反应进行的过程中，由搅拌器浆叶和流体物料之间的相对运动所产生的涡流，必定要引起搅拌轴的振动。6由于下列原因还可能出现轴的窜动：(1)进料不均或液面太低；(2)反应物生成没有控制好，粘度增高；(3)搅拌器的速度突然变化；(4)受热膨胀或压力和温度产生波动。7因为在反应釜的顶部安装密封很不方便。在釜用机械密封的结构方面，必须便于安装和拆卸。以往，机械密封在性能方面产生的故障，有很多是因安装不良而造成的因为现有的釜用机械密封的部件需要逐个安装到反应釜上，要保证其精度很困难。根据用户给定的条件和上述的技术分析，确定下述基本设计思想：1采用安垒性较高的双端面机械密封装置，以保证反应釜的密封性。2从外部向密封室输入清洁适宜的润滑冷却液体进行阻封，并设置冷却水套，以改善密封的运行条件3在密封装置的结构中增设轴承，以减小轴的偏摆和窜动。4考虑便于安装和拆卸以及经济性等因素。四、结构设计特点根据上述设计思想设计的机械密封装置，其摩擦副材料为堆焊硬质合金对碳石墨，辅助密封圈材料：丁晴一4O。具体技术措施；1考虑压力的波动，该密封按30kgfcm设计。上端大气侧密封面所承受的压差大，因此设计成平衡型，为30，静环的支承方法采用双密封0形圈，以减小静环的变形。下部介质侧密封面内外侧压差很小，故设计成非平衡型。值得指出的是，这一端的密封看起来似乎很容易，事实上则不然。如果处理不好引起泄漏，则会污染