机械密封.ppt

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1、西部管道密封培训西部管道密封培训JohnCrane Tech(Tianjin)Co.,Ltd培训内容概述培训内容概述n密封基础知识n密封系统知识n密封的安装要求n密封的失效大致判断n与客户技术人员进行交流机械密封基础机械密封基础 第一部分第一部分Concepts of Mechanical Seals机械密封概念机械密封概念 ShaftProcess Fluid密封流体密封流体Leakage泄漏泄漏Environment环境环境Vessel Wall釜壁釜壁The Basic Sealing Problem:Preventing Leakage基本的密封问题基本的密封问题:防止泄漏防止泄漏Sh

2、aftProcess Fluid流体流动流体流动Leakage泄漏泄漏Environment环境环境 Vessel Wall釜壁釜壁The Concept of anEnd Face Mechanical Seal机械密封端面的概念机械密封端面的概念Shaft Movement轴的运动轴的运动Required Features必须的特征必须的特征nSmall axial clearance小的轴向间隙小的轴向间隙nSelf adjusting自调节自调节Mating Ring配合环配合环Primary Ring补偿环补偿环Secondary Sealing Element辅助密封辅助密封A F

3、lexible Seal Flexible 机械密封机械密封nHydrostatic loading流体静力学负荷流体静力学负荷nSecondary sealing elements辅助密封辅助密封nReplaceable parts可替换的部件可替换的部件O-Ring O型圈型圈Shaft轴轴Mating Ring配合环配合环Primary Ring补偿环补偿环Snap Ring卡环卡环Anti-X Ring 挡环挡环O-Ring O型圈型圈Disk推环推环Springs弹簧弹簧Retainer传动套传动套Set Screw定位螺丝定位螺丝An Example of a Complete S

4、ealSimply put,a mechanical seal is:简单的说简单的说,机械密封就是机械密封就是:1.A wearable,stationary,primary sealing element 一个耐磨一个耐磨,静止的密封件静止的密封件2.A wearable,rotating,primary sealing element 一个耐磨一个耐磨,旋转的密封件旋转的密封件3.A secondary sealing element 二次密封二次密封4.A mechanical loading device to press primary sealing elements 1 and

5、 2 against one another,and 使件使件1和件和件2相互贴合的机械装置相互贴合的机械装置5.Auxiliary components to complete seal 辅助密封辅助密封Non-flashing没有闪蒸没有闪蒸Flashing闪蒸闪蒸Parallel平行平行Converging收敛收敛Diverging发散发散Face Separation密封面分离密封面分离Shape:形态形态Gap:间隙间隙Fluid:流体流体The Sealing Interface密封接触面密封接触面Lubricant润滑剂润滑剂Separation分离面分离面Magnified S

6、urface A 放大面放大面Magnified Surface B放大面放大面Heat热量热量The Sealing Interface密封面密封面nLubrication Purpose:润滑目的润滑目的Separate surfaces分离两个面Prevent contact of high surface points防止出现面接触Reduce friction/heat generation减少摩擦/生热Process Fluid Acts as Lubricant Between Faces流体在两个面之间充当润滑剂的过程流体在两个面之间充当润滑剂的过程Gland密封端盖密封端盖P

7、ump Housing泵腔泵腔Process Fluid工艺流体工艺流体Invisible Leakage:不可见泄漏不可见泄漏Fluid Evaporates Upon Reaching Atmosphere微量的泄漏在大气侧蒸发微量的泄漏在大气侧蒸发 Primary Ring补偿环补偿环Mating Ring配合环配合环Gland密封端盖密封端盖Pump Housing泵腔泵腔No Fluid Or Dry Running没有流体或者干运转没有流体或者干运转Primary Ring补偿环补偿环Mating Ring配合环配合环Without Lubrication,Faces Run Dr

8、y And Overheat 没有润滑干运转导致过热没有润滑干运转导致过热Mating Ring配合环配合环Primary Ring补偿环补偿环Heat Generation 生热生热nRubbing摩擦摩擦nViscous Shear粘性剪切力粘性剪切力Heat Transfer热传递热传递nConduction传导传导nConvection对流对流Injection注入注入Flushing冷冲洗冷冲洗nRemoves Heat带走热量带走热量nReplenishes Cool Clean Lubricating Liquid 补补充润滑液充润滑液Primary Seal:Flush基本密封

9、基本密封:冲洗冲洗Single Seal Flushing By-Pass from Discharge(API Plan 11)单密封通过出口进行冲洗单密封通过出口进行冲洗By-pass Line fromPump Discharge to Seal Gland 从泵出口到密封端盖的管线从泵出口到密封端盖的管线Discharge出口出口Flow流动流动Suction入口入口Primary Seal:Flush基本密封基本密封:冲洗冲洗Minimum Pressure.3 bar/5 psi Above A?最小压力值要大于最小压力值要大于A处处0.3BarFlow流动流动Discharge出

10、口出口Suction入口入口Restrictional Device(Bushing)限流装置限流装置Single Seal Flushing from External Source(API Plan 32)单密封通过外部来源进行冲洗单密封通过外部来源进行冲洗APrimary Seal:Quench 基本密封基本密封:急冷急冷Restrictional Device(Packing)限流装置限流装置(盘根盘根)Quench Source急冷源急冷源Process Fluid工艺流体工艺流体Single Seal Quench from External Source(API Plan 62)

11、单密封通过外部急冷单密封通过外部急冷API Piping PlansAPI 冲洗方案冲洗方案第二部分第二部分JOHNCRANEAPI Piping Plans API 冲洗方案冲洗方案Integral(internal)recirculationfrom pump discharge to seal内部循环从泵的出口到密封内部循环从泵的出口到密封 Advantage Advantage 优点优点 -No external piping 没有外部冲洗 Limitations Limitations 局限性局限性 -Changing flow rate required dismantling o

12、f pump 改变流量需要拆泵 -For clean pumpages only 只能是适用干净的介质API Piping Plans API 冲洗方案冲洗方案Points to Note for API Plan 02:API 02 冲洗方案应注意的事项：冲洗方案应注意的事项：-The injection tapping is used for venting prior to startup.-在开车前，在开车前，入口用来进行放空入口用来进行放空-API plan 02 is often used together with plan 62,especially on high tempe

13、rature bellows seals.冲洗方案冲洗方案2经常与经常与62一起用，特别是用在高温波一起用，特别是用在高温波纹管密封纹管密封API Piping Plans API 冲洗方案冲洗方案No flushing to the mechanical seal(dead-ended)机械密封里没有冲洗机械密封里没有冲洗Points to Note for API Plan 11:API 冲洗方案冲洗方案11 应注意的事项应注意的事项-Use an orifice to restrict the flow rate if the discharge pressure is 3 bar hi

14、gher than seal chamber pressure.如果出口压力高于密封腔如果出口压力高于密封腔压力压力3bar，需要用一个孔限制流量需要用一个孔限制流量-Use on clean and low abrasives duties用在干净，含磨石性颗粒少的用在干净，含磨石性颗粒少的工矿工矿API Piping Plans API 冲洗方案冲洗方案Seal Flushing By-Pass from Discharge单密封通过出口进行冲洗单密封通过出口进行冲洗Recirculation from seal chamber through a flow control orifice

15、 and back to pump suction从密封从密封腔里出通过一个孔板返回到泵的入口腔里出通过一个孔板返回到泵的入口Points to Note for API Plan 13:API 冲洗方案冲洗方案 13 应注意的事项应注意的事项-Use an orifice to restrict the flow rate if the seal chamber pressure is 3 bar higher than suction pressure.如果密封腔压力高于入口压力如果密封腔压力高于入口压力3bar，需要用一个孔板限制流量需要用一个孔板限制流量-handle abrasive

16、s duty better than API plan 11处理含有磨石性颗粒的工矿处理含有磨石性颗粒的工矿13方案号优于方案号优于11方案方案-higher seal chamber pressure to suppress vaporisation较高的密封腔压力可抑制它的汽化较高的密封腔压力可抑制它的汽化API Piping Plans API 冲洗方案冲洗方案+=Points to Note for API Plan 14:API 冲洗方案冲洗方案 14 应注意的事项：应注意的事项：-Flow back to suction side will evacuate vapours tha

17、t may collect in seal chamber.-Recommended for light hydrocarbon service.API Piping Plans API 冲洗方案冲洗方案Recirculation from pump discharge through a flow control orifice and cooler to sealOpen Loop Cooling CircuitOpen Loop Cooling CircuitCooling Water Outlet冷冷水出口水出口Cooling Water Inlet冷水冷水入口入口API Piping

18、 Plans API 冲洗方案冲洗方案Recirculation from a pumping ring in the seal chamber through cooler and back to seal Closed Loop Cooling Circuit Closed Loop Cooling Circuit 冲洗液通过密封冲洗液通过密封腔中的泵效环从密封腔中流出经过换热器，再返回到密封中，形成自封闭腔中的泵效环从密封腔中流出经过换热器，再返回到密封中，形成自封闭循环。循环。形成封闭的冷却回路形成封闭的冷却回路形成封闭的冷却回路形成封闭的冷却回路Throat bushingSucti

19、on入口入口Discharge出出口口18-24Vent at highest point of the piping排排气在管线气在管线的最高点的最高点Cooling Water Outlet冷冷水出口水出口Cooling Water Inlet冷冷水入口水入口mechanical seal with pumping ringHeat exchanger换热器换热器API Piping Plans API 冲洗方案冲洗方案Points to note for API Plan 23:nThermosyphon design热虹吸设计 *heat exchanger 换热器*18 to 24“

20、above pump centre line.*在泵中心线以上 18 to 24 *Prevent overheating in standby and startup.*在泵启动和备用时，要防止过热。nInstall close fitting neck bushing at the bottom of seal chamber to isolate the heat from the impeller end.在密封腔底部安装喉部衬套用来隔离从叶轮传出的热量nUsed on high temperature applications to minimise heat load on the

21、 cooler by cooling only small amount of liquid that is recirculated.用于高温工况，通过冷却密封腔的小部分的循环流体来使冷却器的热负荷降至最低.nFor high temperature boiler feed pump applications用于高温锅炉给水泵上nOther applications其他应用 n*high temperature liquid close to bubble point.n*接近沸点的高温液体.API Piping Plans API 冲洗方案冲洗方案Recirculation from pu

22、mp discharge through a cyclone separator delivering clean fluid to the seal and fluid with solids back to pump suction line冲洗液从泵出口流出，通过一旋液分离器，使干净流体进入冲洗液从泵出口流出，通过一旋液分离器，使干净流体进入密封腔，带有颗粒的流体返回到泵入口处形成封闭循环密封腔，带有颗粒的流体返回到泵入口处形成封闭循环Clean overflowUnderflowInletAPI Piping Plans API 冲洗方案冲洗方案Points to Note for A

23、PI Plan 32:对于对于API plan 32 须注意须注意:-Chose a proper source of seal flush to eliminate the potential for vaporisation of the injected fluid and to avoid contamination of the fluid being pumped with the injected flush.选择合适的密封冲洗源，选择合适的密封冲洗源，以减少冲洗流体的汽化，同时可避免以减少冲洗流体的汽化，同时可避免冲洗流体被污染。冲洗流体被污染。-Install a labyr

24、inth bushing at the bottom of the stuffing box to control the flushing and pressure if necessary.-如有必要的话，在密封腔底部安装如有必要的话，在密封腔底部安装喉部衬套或迷宫密封来控制冲洗和压喉部衬套或迷宫密封来控制冲洗和压力。力。API Piping Plans API 冲洗方案冲洗方案Single Seal Flushing from External Source单密封通过外部来源进行冲洗单密封通过外部来源进行冲洗Throat BushingRecirculation from pump di

25、scharge through a cyclone separator delivering clean fluid through a cooler and then to seal and fluid with solids back to pump suction lineCooling Water OutletCooling Water InletAPI Piping Plans API 冲洗方案冲洗方案Needle valveExternal reservoir providing a dead-ended blanket of fluid to the quench connect

26、ion of the gland.Points to Note for API Plan 51:对于对于API plan 51 须注意须注意:-Dead ended blanket on atmospheric side of seal to prevent freezing of moisture.Seal face will not stick together when the pump started.-在密封大气侧，一端封闭的在密封大气侧，一端封闭的情况可防止潮气的冻结，这样情况可防止潮气的冻结，这样在泵启动时，密封面就不会在泵启动时，密封面就不会粘接在一起。粘接在一起。Typica

27、l application:Typical application:典型的应用典型的应用典型的应用典型的应用Pump operating below 0 C应用于泵在应用于泵在 0C以下以下-API 610 8th Edition has eliminated this piping plan.API 610 第八版已经取消这个冲洗方第八版已经取消这个冲洗方案案-API Piping Plans API 冲洗方案冲洗方案API Piping Plans API 冲洗方案冲洗方案s A fluid used as a lubricant or buffer between dual mechan

28、ical seals.这种液体象缓冲剂，润滑剂这种液体象缓冲剂，润滑剂用在双机械密封用在双机械密封s The buffer fluid is always at a pressure lower than the pump process pressure being sealed.缓冲缓冲液的压力通常低于被密封的介质的压力液的压力通常低于被密封的介质的压力s A fluid which is introduced between dual mechanical seals to completely isolate the pump process liquid from the envir

29、onment.双机械密封里的隔离液用于是泵的工双机械密封里的隔离液用于是泵的工艺液体与大气分离艺液体与大气分离s Pressure of the barrier fluid is always higher than the pump process pressure being sealed.隔离液压力总是高于隔离液压力总是高于泵的运作压力泵的运作压力The purpose of fluid circulationis to remove heat from mechanical sealAPI Piping Plans API 冲洗方案冲洗方案Pumping ringPumpn On ap

30、plications below ambient temperature,circulation of barrier fluid may not be desirable.这种情况适用这种情况适用于比室温低的工况，隔离液的循于比室温低的工况，隔离液的循环不能满足要求。环不能满足要求。The atmosphere will heat the reservoir and consequently add heat to the seal area.外部对储罐进行加热，外部对储罐进行加热，从而，对密封区域进行加热。从而，对密封区域进行加热。T2T1n Fluid circulation by te

31、mperature difference between the seal and reservoir.流体依靠密封腔和流体依靠密封腔和储罐的温差进行循环储罐的温差进行循环 n Higher temperature liquid at seal has lower density rises to the reservoir.密封中的高温流体密封中的高温流体密度较小，依靠热虹吸现象上密度较小，依靠热虹吸现象上升到储罐中升到储罐中 n Lower temperature liquid at reservoir has higher density falls to the seal to pro

32、vide cooling.储罐中的低储罐中的低温流体密度较大，下降到密封温流体密度较大，下降到密封腔中对密封进行冷却腔中对密封进行冷却API Piping Plans API 冲洗方案冲洗方案Points to Note for API Plan 52:nTypically used with an Arrangement 2 unpressurised dual seal.通常用于不带压双封通常用于不带压双封 nDuring normal operation,circulation is maintained by an internal pumping ring.在正常在正常操作情况下，通

33、过腔内的泵效环维持循环操作情况下，通过腔内的泵效环维持循环 n The reservoir is usually continuously vented to a vapour recovery system and is maintained at a pressure less than the pressure in the seal chamber.储罐通常与回收系统相连通，罐内压力通储罐通常与回收系统相连通，罐内压力通常低于密封腔压力常低于密封腔压力Pressure Gauge 压力计Level Gauge 水准仪Fill valveOrificeDrainLevel Switch(

34、H)电平开关Level Switch(L)Pressure Switch 压力开关(Normally Open)Vent valve 排气阀 External reservoir providing buffer fluid for the outer seal of an unpressurised dual seal arrangement.外部储罐对不带压双封的外密封起缓冲液的作用外部储罐对不带压双封的外密封起缓冲液的作用API Piping Plans API 冲洗方案冲洗方案Pressure Gauge 压力表Level Gauge 水准仪Level Switch(L)电平开关Ven

35、t Valve 排气阀(Normally Close)通常关着OrificePressure Switch 压力操纵开关 External Pressure 外部压力外部压力 SourceOne-way Block Valve(Normally Open)Points to Note for API Plan 53:nTypically used with an Arrangement 3 pressurised dual seal.通常用于带压双封通常用于带压双封 nDuring normal operation,circulation is maintained by an interna

36、l pumping ring.在正常在正常操作情况下，通过腔内的泵效环维持循环操作情况下，通过腔内的泵效环维持循环n The reservoir pressure is greater than the process pressure being sealed.罐内压力通常高罐内压力通常高于被密封介质压力于被密封介质压力 External reservoir providing pressurised barrier fluid for the outer seal of an pressurised dual seal arrangement.外部储罐对带压双封的外部储罐对带压双封的外密封

37、起隔离液的效果外密封起隔离液的效果DrainAPI Piping Plans API 冲洗方案冲洗方案Points to Note for API Plan 54:nTypically used with an Arrangement 3 pressurised dual seal.通常用于带压双封通常用于带压双封nDuring normal operation,circulation is maintained by an external pump or pressure system.在正常操作情况下，通过外在正常操作情况下，通过外部的泵或压力系统维持循环部的泵或压力系统维持循环n Th

38、e circulating barrier fluid pressure is greater than the process pressure being sealed.循环隔离液的压力高于被密封介质的循环隔离液的压力高于被密封介质的压力压力 External barrier fluid system providing pressurised barrier fluid for the outer seal of an pressurised dual seal arrangement外部隔离液系统对带压双封的外密封提供带压隔离液外部隔离液系统对带压双封的外密封提供带压隔离液 API P

39、iping Plans API 冲洗方案冲洗方案nSafe to use,handle,store储藏、操作、使用安全可靠nStable liquid at ambient temperatures在室温下，性能稳定 nNot a VOC,VHAP or other regulated compoundn不易挥发、非有毒物质nNon flammable不易燃烧nNon foaming when pressurised高于常压时，不易起泡nClean and good lubricity干净且有较好的润滑性nCompatible with process fluid与工艺流体有互容性nCompa

40、tible with seal materials与密封材料相一致nGood heat transfer properties有好的传热性能 nGood flow qualities at very low temperaturesn 在低温下，有好的流动性nLow solubility of gas对气体有较低的溶解性nLocal availability当地容易获得nLow cost成本低 VOC:Volatile Organic CompoundVHAP:Volatile Hazardous Air PolutantsAPI Piping Plans API 冲洗方案冲洗方案Tapped

41、 connections for the purchasers use在接口处攻螺纹，以方便用户使用在接口处攻螺纹，以方便用户使用Point to Note for API Plan 61:对对于于API plan 61 须注意须注意:nTypically this plan is used when the purchaser is to provide fluid(such as steam,gas,or water)to an auxiliary sealing device.n通常在买方能给密封辅助系统通常在买方能给密封辅助系统提供流体（如蒸汽、气体或水）提供流体（如蒸汽、气体或水）的

42、情况下，才采用该方案的情况下，才采用该方案API Piping Plans API 冲洗方案冲洗方案Points to Note for API Plan 62:n对于对于API plan 62 须注意须注意:nThe quench may be required to prevent solids from accumulating on the atmospheric side of the seal.增加吹扫口以防止在密封大气增加吹扫口以防止在密封大气侧有颗粒的积累侧有颗粒的积累nTypically used with a close-clearance throttle bushing

43、.n普遍使用节流衬套普遍使用节流衬套API Piping Plans API 冲洗方案冲洗方案Single Seal Quench from External Source单密封通过外部急冷单密封通过外部急冷API 682 2nd Edition API 682 第二版第二版New Piping Plans 新的冲洗方案新的冲洗方案nPlan 14(Plan 11+13)冲洗方案冲洗方案14nPlan 53s-Arrangement 3,Contacting Wet(CW)Seals 53 方案方案-排列方案排列方案3，接触式湿密封，接触式湿密封53a traditional configur

44、ation 传统构造53b bladder accumulator 蓄能器53c piston pot/accumulator 活塞/蓄能器nContainment Seal 二次辅助密封二次辅助密封Plan 72 Arrangement 2 w/Containment Seal(CS)Plan 75 Arrangement 2 w/Containment Seal(CS)Plan 76 Arrangement 2 w/Containment Seal(CS)nGas Barrier Seals 气体气体Plan 74 Arrangement 3,Non-Contacting(NC)Seals

45、排列方式3，非接触式密封 Plan 53a(A.4.12)Arrangement 3,Contacting Wet(CW)Seals排列方式3，接触式湿密封Dual Pressurised(Double)Seals 带压双封Utilises direct nitrogen blanket for pressure利用氮气层来增压due to nitrogen entrainment in the barrier liquidAPI 682 limits the maximum nitrogen pressure to 10 barg,JC recommendation is maximum n

46、itrogen pressure 21 barg,as long as the barrier fluid temperature is less than 120C API 682 限制了氮气的最大压力为10barg,约翰克兰建议只要隔离液温度小于120度，最大氮气压力21barg,API 682 2nd Edition API 682 第二版第二版 New Piping Plans 新的冲洗方案新的冲洗方案 Plan 53b(A.4.12)Arrangement 3,Contacting Wet(CW)Seals 排列方式3，接触式湿密封Dual Pressurised(Double)Se

47、als 带压双封Utilizes bladder accumulator for pressure 利用蓄能器来增压Bladder eliminates nitrogen contact with barrier liquid蓄能器把氮气与隔离液分开Allows for higher pressure applications 允许高压力应用Configuration Includes:Accumulator 蓄电池Pressure Indicator 压力显示器Pressure Switch压力开关Heat Exchanger换热器BIBOTIBIBOFWhen SpecifiedAPI 6

48、82 2nd Edition API 682 第二版第二版New Piping Plans 新的冲洗方案新的冲洗方案 Plan 53c(A.4.12)Arrangement 3,Contacting Wet(CW)Seals排列方式3，接触式湿密封Dual Pressurised(Double)Seals 带压双封Utilizes piston pot for pressure 利用活塞增压BIBOBIBOFWhen SpecifiedAPI 682 2nd Edition API 682 第二版第二版New Piping Plans 新的冲洗方案新的冲洗方案 Plan 53c(A.4.12)

49、Allows for higher pressure applications 允许高压力应用Configuration includes:构造包括Piston pot 活塞Pressure indicator压力显示器Pressure switch 压力开关Heat exchanger换热器Level switch电平开关Piston pot eliminates nitrogen contact with barrier liquid活塞缸阻断了隔离液与氮气的连接Piston provides constant pressure ratio to seals(1.1:1)活塞给密封提供持续

50、的压力比率Spring 弹簧API 682 2nd Edition API 682 第二版第二版New Piping Plans 新的冲洗方案新的冲洗方案Barrier Fluid Temperature(7.3.4.1.1)隔离流体温度隔离流体温度nLiquid barrier systems shall be designed such that that maximum temperature differential between the barrier fluid inlet and outlet immediately adjacent to the seal chamber i