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1、约翰克兰机械密封产品与应用,机械密封概述:定义:机械密封(端面密封)-由至少一对垂直于轴线的端面在流体压力和补赏机构 弹力(或磁力)的作用下以及辅助密封的配合下,保持贴合并相对滑动而构成 防止流体泄漏的装置.基本结构:端面密封磨擦付缓冲补赏和压紧机构辅助密封(二级密封挠性元件)传动机构基本密封点:端面主密封点静环与端盖辅助密封点动环与轴(轴套)辅助密封点端盖与泵体连接密封点此外为了保证和提高机械密封的密封效果延长使用寿命,采取不同端面的组合，增加如冲洗,节流冷却,阻封和杂质过滤等辅助系统.,How a mechanical seal work?,to separate the two slid
2、ing faces to lubricate the sliding faces to reduce friction/heat generation to prevent fluid leakage to the atmosphere,The seal faces are lapped very flat(1 to 2 lightbands).A very thin fluid film(3 to 5 microns)is formed and served the following purposes:,Face,Seat and Springs,Secondary Seals,0。294
3、 m,The Sealing Interface,Primary Seal Film Thickness主密封膜厚度,Fluid film thickness is very importanttoo thin-wear,causing early seal failuretoo thick-visible leakageMust be:present-beware dry runningstableclean-beware abrasive wear symptomsreasonable viscositytemperature controlledacceptable pressure,约
4、翰克兰机械密封产品与应用,摩擦副端面检测：利用光波的干涉 效应测量工具：平晶光源：钠光原理：光波干涉 干涉条纹按图示产生光带确定密封端面平面度1光带=0。294m=0。588m（=钠光波波长）,约翰克兰机械密封产品与应用,Family B：推进型“O”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：Type 58U,58B,8-1,8B1,48,5610,5620Type 1648,2648,3648(符合API 682标准
5、)鉴于约翰克兰开发 ISOLAST高氟橡胶(全氟醚橡胶)，该材料耐强腐蚀，高温(-200C-3250C)致使“O”型密封得到更广泛应用,Family B推进型“O”型低泄漏盒式密封,约翰克兰机械密封产品与应用,集装式盒式密封特点及优点:结构特点:密封包括端盖,轴套完整提供 设计特点:改善,提高热交换效率 材料优选 结构优选 抗热变形及抗压力变形设计 产品优点:简便,迅速,快捷的安装 无需测量安装长度 使用前在车间组装并做静压试验 保证密封安装的清洁度 标准的零部件-有效的成本及较短的交货期,热量引起的变形,压力引起的变形,平行面接触稳定运行状态,密封面接触变形分析,约翰克兰机械密封产品与应用,
6、热量引起变形的趋势,集合于点（线）接触泄露通道,约翰克兰机械密封产品与应用,特点及优点：“O”形推进式机械密封设计低泄漏的密封设计可组合为单级，双级串联集装式密封根据不同介质工况选择应用不同的动，静环及 结构设计多种规格，不同优质材料组合应用,约翰克兰机械密封产品与应用,EXTENDED FLUSH,CIRCUMFERENTIAL FLUSH,DISTRIBUTED FLUSH,Type 8B1 Flush Arrangements,二次节流密封,不带二次节流单密封将允许主密封正常的介质泄露排放至大气侧对于如下因素不可接受:危险或有毒介质流体易挥发流体环保要求二次密封可将主密封泄露 引到安全区
7、域当主密封失效，二次节流密封也可使设备以一种可控制的方式切换停车。,约翰克兰机械密封产品与应用,Item,Description,1,2,3,4,5,6,Garter Spring,Segmental Bushing,Spring,O-Ring,Follower Plate,Cap Screw,1,3,2,4,6,5,Hard Deposit,Secondary Containment,segmented carbon bush,约翰克兰机械密封产品与应用,炼油和化学工业对机械密封要求的最新趋势:高工况，高参数 期望延长使用寿命.密封标准化/减少现场的调试/减少库存.有计划的间隔维修/防止故障
8、间隔维修.远程监测/监控 环保要求-零泄漏 可靠性.安全性,约翰克兰机械密封产品与应用,API 682 机械密封标准(第二版)机械密封 石油化工 泵制造商 制造商 工业 主机厂 API 682 的最终目的是可靠性,安全性,减少泄漏 机械密封使用寿命最低为三年 节能问题倍受关注,以寿命成本为考核依据 满足 最终用户的利益,约翰克兰机械密封产品与应用,机械密封辅助系统应用:基本系统-为保证机械密封正常使用,选用正确的密封辅助系统,增加如冲洗,循环,抗温,抗压,排渣,节流,润滑,防结晶,防介质泄漏等功能,改善机械密封的工作环境,从而保 证机械密封的正常运行.基本系统功能:控制泄漏 控制压力控制磨蚀
9、控制腐蚀防污染 防泄漏基本系统分类:API 610 PLAN 系统介质冲洗 API 610 PLAN 01,11,12,13,14，21,22,23,31,41外流体冲洗 API 610 PLAN 32,51，（61）62缓冲液（气）循环系统 API 610 PLAN 52，72隔离液（气）循环系统 API 610 PLAN 53A,53B,53C,54，74收集与排放系统 API PLAN（71），75，76,API Piping Plans API 冲洗方案,Integral(internal)recirculationfrom pump discharge to seal内部循环从泵的出
10、口到密封,Advantage 优点-No external piping 没有外部冲洗 Limitations 局限性-Changing flow rate required dismantling of 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,Points to Note for API Plan 02:API 02 冲洗方案应注意的事项：The injection tapping is used for venting prior to startup.-在开车前，入口用来进行放空
11、API plan 02 is often used together with plan 62,especially on high temperature bellows seals.冲洗方案2经常与62一起用，特别是用在高温波纹管密封,API Piping Plans API 冲洗方案,No flushing to the mechanical seal(dead-ended)机械密封里没有冲洗,Points to Note for API Plan 11:API 冲洗方案11 应注意的事项-Use an orifice to restrict the flow rate if the d
12、ischarge pressure is 3 bar higher than seal chamber pressure.如果出口压力高于密封腔压力3bar，需要用一个孔限制流量-Use on clean and low abrasives duties用在干净，含磨石性颗粒少的工矿,API Piping Plans API 冲洗方案,Seal Flushing By-Pass from Discharge单密封通过出口进行冲洗,API Piping Plans API 冲洗方案,Overhung Pump 1 seals,API Piping Plans API 冲洗方案,Overhung
13、Pump 1 seals,Recirculation from seal chamber through a flow control orifice and back to pump suction从密封腔里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 13 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3bar，需要用一个
14、孔限制流量-handle abrasives duty better than API plan 11处理含有磨蚀性颗粒的工况13方案好于11方案-higher seal chamber pressure to suppress vaporisation较高的密封腔压力可抑制它的汽化,API Piping Plans API 冲洗方案,+,=,Points to Note for API Plan 14:API 冲洗方案 14 应注意的事项：-Flow back to suction side will evacuate vapours that may collect in seal cha
15、mber.-Recommended for light hydrocarbon service.,API Piping Plans API 冲洗方案,Recirculation from pump discharge through a flow control orifice and cooler to sealOpen Loop Cooling Circuit,Cooling Water Outlet冷水出口,Cooling Water Inlet冷水入口,API Piping Plans API 冲洗方案,API Piping Plans API 冲洗方案,API Piping Plan
16、s API 冲洗方案,Recirculation from a pumping ring in the seal chamber through cooler and back to seal Closed Loop Cooling Circuit 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，形成自封闭循环。形成封闭的冷却回路,Throat bushing,Suction入口,Discharge出口,18-24,Vent at highest point of the piping排起在管线的最高点,Cooling Water Outlet冷水出口,Cooling Wa
17、ter Inlet冷水入口,mechanical seal with pumping ring,Heat exchanger换热器,API Piping Plans API 冲洗方案,Points to note for API Plan 23:Thermosyphon design热虹吸设计*heat exchanger 换热器 18 to 24“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。Install close fitting nec
18、k 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Used on high temperature applications to minimise heat load on the 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.For high temperature bo
19、iler feed pump applications用于高温锅炉给水泵上Other applications其他应用*high temperature liquid close to bubble point.*接近沸点的高温液体.,API Piping Plans API 冲洗方案,Recirculation from pump 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
20、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,API Piping Plans API 冲洗方案,Points to Note for API Plan 32:对于API plan 32 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
21、封冲洗源，以减少冲洗流体的汽化，同时可避免冲洗流体被污染。-Install a labyrinth bushing at the bottom of the stuffing box to control the flushing and pressure if necessary.-如有必要的话，在密封腔底部安装喉部衬套或迷宫密封来控制冲洗和压力。,API Piping Plans API 冲洗方案,Single Seal Flushing from External Source单密封通过外部来源进行冲洗,Throat Bushing,API Piping Plans API 冲洗方案,C
22、lean external flush,API Piping Plans API 冲洗方案,Clean external flush,Tapped connections for the purchasers use在接口处攻螺纹，以方便用户使用,Point to Note for API Plan 61:对于API plan 61 须注意:Typically this plan is used when the purchaser is to provide fluid(such as steam,gas,or water)to an auxiliary sealing device.通常在
23、买方能给密封辅助系统提供流体（如蒸汽、气体或水）的情况下，才采用该方案,API Piping Plans API 冲洗方案,Points to Note for API Plan 62:对于API plan 62 须注意:The 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侧有颗粒的积累Typically used with a close-clearance throttle bushing.普遍使用节流衬套,API Pi
24、ping Plans API 冲洗方案,Single Seal Quench from External Source单密封通过外部急冷,API Piping Plans API 冲洗方案,e.g steam quench,Plan 75(A.4.18),Arrangement 2,w/Containment Seal(CS)排列方案2，二次辅助密封Dual Un-Pressurised(Tandem)Seals 双无压密封Dry-running secondary 辅助密封干运转Condensate collection reservoir(8.6.5.2)冷凝液收集罐Used when p
25、rimary seal leakage may condense(does not completely vaporize)用于从主密封泄漏出来的可冷凝的工况May be used in conjunction with Plan 72 或许和72方案一起使用,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 76(A.4.19),Arrangement 2,w/Containment Seal(CS)排列方式2，二次辅助密封Dual Un-Pressurised Seals(Dry-running secondary)双无压密封Primary leakage routed to flare or ventUsed when primary seal leakage will not condense(completely vaporizes)用于从主密封泄漏出的不可冷凝的工况Essentially a 48SC or 28LD panel leakage detection May be used in conjunction with Plan 72 或许和72方案一起使用,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,
