机械密封基础知识(二)

2006新进员工技术培训资料之三机械密封基础知识（二）主要内容JohnCrane机械密封产品介绍机械密封辅助系统介绍机械密封的布置方式——单端面密封Single单密封•InsideMounted内装式单端面密封布置方式SingleSealArrangementsProcessFluid工艺流体Shaft轴Atmosphere大气Single单密封•OutsideMounted外装式单端面密封布置方式SingleSealArrangementsProcessFluid工艺流体Shaft轴Atmosphere大气InsideMounted内部安装MatingRing非补偿环Atmosphere大气Shaft轴GlandPlate压盖PumpHousing泵腔SealHead密封头ProcessFluid工艺流体SealHead密封头ProcessFluid工艺流体OutsideMounted外部安装PumpHousing泵腔Atmosphere大气GlandPlate压盖Shaft轴MatingRing非补偿环单端面密封布置方式SingleSealArrangementsRotatingHead&RotatingSeat旋转头和旋转座UseRotatingHeadAssembliesupto:3500fpmforSingleSpringDesigns5000fpmforMultipleSpringDesignsSealHeadSeat{RotatingRotatingHead旋转头SealHeadSeatRotatingRotatingSeat旋转座Stationary{{StationaryAdvantages优点LessRadial&AxialSpaceRequirements需要的径向和轴向空间小LowerCost成本更低Advantages优点HigherSpeedCapability更高的转速ToleratesMisalignmentBetter对中精度要求不高BetterCooling更好的冷却性能单端面密封布置方式SingleSealArrangements{机械密封的布置方式——多级密封一个单端面密封是不够的Singlesealsutiliseprocessfluidtoprovidethelubricatinginterfacefilm单端面密封通常采用介质润滑密封面Usemultiplesealsif:•fluidistoxic介质有毒•fluidisflammable易燃•environmental污染环境•isolationrequired不允许泄漏•fluidchangesstate介质发生相变•fluidisnotagoodlubricantorisagas介质润滑性差或是气体•fluidisunstable介质不稳定•dryrunninglikely可能干运转•expensiveproduct介质昂贵•criticalpump重要的泵串联密封MultipleSeals:TandemBasictandemnon-pressuriseddoubleProductlubricatesthisseal靠介质润滑Thissealisunderfullproductpressure承受全部压力InboardSeal内侧密封Notepossiblecontaminationofbarrierfluid注意介质可能污染密封液UseAPIPlan52串联密封MultipleSeals:TandemCleanbarrierfluidlubricatesthisseal靠洁净的密封液润滑OutboardSeal外侧密封Barrierfluidisatlow(atmospheric)pressure.密封液压力比较低UseAPIPlan52Basictandemnon-pressuriseddouble串联密封MultipleSeals:TandemInboardsealmostlikelytofailfirst一般内侧密封先失效Barrierfluidlevel/pressurewillrise密封液压力升高Outboardsealactsassecondarycontainment外侧密封作为二次密封Processcancontinueuntilcompleted密封仍然可以维持一段时间UseAPIPlan52Basictandemnon-pressuriseddouble多级密封：背对背MultipleSeals:DoubleBack-to-BackBasicback-to-backpressuriseddoublesealPressurisedbarrierfluidiscirculatedroundtheseals通入高压密封液Thislubricatesbothsetsofsealfaces密封液润滑两个密封面UseAPIPlan53Iftheoutboardsealfails,thebarrierpressurewillfailandpumpmustbeswitchedoffasproductwillleakout如果外侧密封失效，无法维持密封液压力，泵必须停止使用UseAPIPlan53Basicback-to-backpressuriseddoubleseal多级密封：背对背MultipleSeals:DoubleBack-to-BackStationarysealsRotatingMatingRing•Similarinoperationtoback-to-backdoubleseal与背靠背双端面密封类似•Muchshorterarrangement-onlyoneseat轴向尺寸更短—只有一个动环•Simplerotatingcomponents旋转组件结构简单多级密封：面对面MultipleSeals:DoubleFace-to-Face辅助密封辅助密封SecondaryContainmentLeakagedirectlytoatmosphere辅助密封SecondaryContainmentRequiredto:containhazardousemissions防止泄漏containproductleakagewhenmainmechanicalsealfinallyfails当主密封失效时防止介质泄漏isolateproductfromtheatmosphere隔离介质和大气•Coking结焦•Crystallising结晶•Freezing凝固•Polymerising聚合containaquenchforotherreasons(e.g.cooling)冷却、冲洗辅助密封SecondaryContainmentNon-contactingdevicesContactingDevicesABCDEFG急冷与冲洗QuenchandFlushQuench急冷•lowpressure(0.5barg)压力低•lowflow(0.5litres/minute)流量低•externaltomainseal从外部引入•nocontamination对介质无污染•nodilution没有稀释作用Flush冲洗•highpressure(1.0barabovesealpressure)压力高•injectedintosealchamber注入密封腔•coolspumpedproduct冷却介质•dilutespumpedproduct对介质有稀释作用辅助密封——碳环SecondaryContainment–BushingsNon-contacting非接触Fixednon-sparkingthrottlebush固定安装，防火花衬套MinimumrequirementforAPI610满足API610最低要求Leakagereduction较少泄漏量Anyshaftmovementwillcausewear轴的任何位移都将导致磨损UseAPIPlan61Non-contacting非接触Floatingcarbonbush浮动碳环MinimumrequirementforAPI682满足API682的最低要求Moveswiththeshaft与轴一起移动Leakagereduction较少泄漏量Steamquench蒸汽急冷Lesswear减少磨损Longerlife寿命长UseAPIPlan61辅助密封——碳环SecondaryContainment–BushingsNon-contacting(close)非接触Floatingcarbonbush浮动碳环Oftensegmentedforeaseofreplacement分瓣MinimumrequirementforAPI682满足API682最低要求Moveswiththeshaft与轴一起移动Leakagereduction泄漏量减少Steamquench蒸汽急冷Lessleakage泄漏量更少Longerlife寿命更长UseAPIPlan61辅助密封——碳环SecondaryContainment–BushingsContactingorNon-contactingMaterialstosuitNon-contacting•actslikeplainbush•canbecompressedwhensealleaks辅助密封——碳环SecondaryContainment–BushingsContactingorNon-contactingMaterialstosuitNon-contacting•actslikeplainbush•canbecompressedwhensealleaksContactingmustsupplycontinuousquenchUseAPIPlan62or51辅助密封——碳环SecondaryContainment–BushingsContacting接触型VariouslipsealtypedevicesIsolateproductfromatmosphereandcontainanyleakageMustsupplylubricantatalltimes(quench)必须有润滑Lowpressuresonly只能用于低压UseAPIPlan62or51辅助密封——唇封SecondaryContainment–LipSealsContacting接触型Lipsealreversed唇封反装Idealforgreaselubrication最好用脂润滑Actsassafetyvalve作为安全密封Usedinpaperandsugarindustries用于造纸和制糖业UseAPIPlan62or51辅助密封——唇封SecondaryContainment–LipSeals约翰克兰机械密封产品介绍约翰克兰机械密封产品介绍FamilyA非推进型橡胶波纹管机械密封特点：自动平衡型，不易阻塞；具有缓冲补偿和密封的双重功能具有较高内阻，可同时承受多向载荷不考虑旋向，安装拆卸简单方便批量生产，价格便宜基本密封型号：Type1,1A,1B,1100Type2,2B,502,521Type6A推荐型号：Type2100约翰克兰机械密封产品介绍FamilyB：推进型“O”型圈二次密封机械密封特点：结构简单，二次密封为“O”型柔性件结构便于安装与维修不损伤轴(轴套)表面双旋向结构设计具有非平衡，平衡型两种设计选用不同材料应用范围广泛经改型设计，广泛应用于烃泵易挥发介质基本密封型号：Type58U,58B,8-1,8B1,48,5610,5620Type1648,2648,3648(符合API682标准)约翰克兰机械密封产品介绍FamilyC：非推进型PTFE波纹管机械密封特点：外装PTFE波纹管设计