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1、1,Basic Mechanical Seals密封基础知识,JC Tianjin Training,2,rotating seal unit,two flat sliding surfaces,which maintain a close running clearance while separated by a fluid film两个光滑平面之间维持着一个由流体膜隔开的微小间隙,stationary seal unit,What is a mechanical seal?什么是机械密封？,Desired Features of a Seal机械密封必须有的特征,Long-life 很长
2、的寿命Easy maintenance 容易检修Low cost 低成本,Small axial clearance 小的轴向间隙Self adjusting 自调节,Shaft Movement轴的运动,4,Basic Mechanical Seal基础机械密封,Loose ring set screwed to the shaft把一个有间隙的环用顶丝固定在轴上,1,5,Basic Mechanical Seal基础机械密封,O-ring prevents leakage through the bore,2,6,Basic Mechanical Seal基础机械密封,Spring ens
3、ures automatic adjustment弹簧确保自动调整,3,7,Basic Mechanical Seal基础机械密封,4,8,Basic Mechanical Seal基础机械密封,5,9,Basic Mechanical Seal基础机械密封,Gasket or O-ring,SEAT,Recirculationfor cooling,SPRING OR SPRING FORCE,O-Ring O型圈,Shaft轴,Mating Ring配合环,Primary Ring补偿环,Snap Ring卡环,Anti-X Ring 挡环,O-Ring O型圈,Disk推环,Spring
4、s弹簧,Retainer传动套,Set Screw定位螺丝,An Example of a Complete Seal一个完整密封的例子,Simply put,a mechanical seal is:简单的说,机械密封就是:,1.A wearable,stationary,primary sealing element 一个耐磨,静止的密封件2.A wearable,rotating,primary sealing element 一个耐磨,旋转的密封件3.A secondary sealing element 二次密封4.A mechanical loading device to pre
5、ss primary sealing elements 1 and 2 against one another,and 使件1和件2相互贴合的机械装置5.Auxiliary components to complete seal 使密封更加完善的辅助件,12,不像一个机械密封而更像一个限制装置,需要泄漏否则将会灼伤.会磨损轴或轴套高功耗用来克服磨擦产品损失需要大量的水安装,维修和盘根调整需要停车时间泄漏导致设备破坏和摧毁,不可见泄漏、机械密封和盘根之间的泄漏率在1到100或者更好证明机械密封的寿命可达8到10年毫无故障无产品损失,节省水和能量可以节省成本安装后维修很少密封有潜在危害的物质时机械
6、密封可以提供更好的安全性,Gland Packing v.Mechanical Seals盘根和机械密封,13,SPRING FORCEFLUID PRESSURE,fluid film(3-5 microns),a thin film of liquid forms the primary(dynamic)seal between the rotating and stationary elements在旋转件和静止件之间形成很薄的液膜,FILM REACTION,Primary Seal 主密封,14,Faces lapped flat to within 1-3 light bands.
7、,Primary Seal Film Thickness主密封膜厚度,15,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 running谨防干运转Stable稳定 谨防磨损征兆clean-beware abrasive wear symptomsreasonable viscosity合理的黏度temperature
8、 controlled受控的温度acceptable pressure允许的压力,16,Primary Seal Face Flatness主密封平面,If faces not flat,contact generates heatExcessive wear-short life,1 light band=0.0000116 inch or 0.0003 mm,Lubricant 润滑剂,Separation分离面,Magnified Surface A 放大面,Magnified Surface B 放大面,Heat热量,The Sealing Interface 密封面,Lubricat
9、ion Purpose: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,Gland密封端盖,Pump Housing泵腔,Process Fluid工艺流体,Invisible Leakage:不可见泄漏Fluid Evaporates Upon Reaching Atmosphere微量的泄漏在大气侧
10、蒸发,Primary Ring补偿环,Mating Ring配合环,Gland密封端盖,Pump Housing泵腔,No Fluid Or Dry Running没有流体或者干运转,Primary Ring补偿环,Mating Ring配合环,Without Lubrication,Faces Run Dry And Overheat没有润滑干运转导致过热,20,常用动环材料,Face(Primary Ring)Materials 动环材料Carbon-graphite 碳石墨类resin impregnated 树脂浸渍（171）antimony impregnated 金属锑浸渍（218
11、）Carbon converted to Silicon Carbide 硅化石墨（121）CVR 化学汽相反应硅化石墨CVD 化学汽相沉积硅化石墨Solid Silicon Carbide 碳化硅Sintered silicon carbide 无压烧结碳化硅(277)Reaction silicon carbide 反应烧结碳化硅（088）Sintered silicon carbide with controlled porosity 微孔碳化硅（584）Tungsten Carbide 碳化钨Cobalt bonded 钴基碳化钨（025）Nickel bonded 镍基碳化钨（005
12、）,21,常用静环材料,Seat(Mating Ring-Narrow)Materials 静环材料Ceramic 陶瓷99.7%Aluminium Oxide 氧化铝(059)Solid Silicon Carbide 碳化硅Sintered silicon carbide 无压烧结碳化硅(277)Reaction silicon carbide 反应烧结碳化硅（088）Sintered silicon carbide with controlled porosity 微孔碳化硅（584）Tungsten Carbide 碳化钨Cobalt bonded 钴基碳化钨（025）Nickel b
13、onded 镍基碳化钨（005）,22,Secondary Seal 二次密封,Three basic forms三种基本形式o-rings o型圈Wedges 楔形环Bellows 波纹管Elastomer 橡胶的Metal 金属的Formed 成型的edge welded 焊接的PTFE,Two groupsPusher推进式Sliding滑移o-rings wedgesNon-pusher非推进式Bellows风箱,Teflon Bellows聚四氟乙烯波纹管,Elastomeric Bellows橡胶波纹管,Half Convolution半波,Welded Metal Bellows
14、焊接金属波纹管,V RingsV型圈,U Cup杯型,Wedge楔形,Encapsulated O Ring包覆 O型圈,O RingO型圈,Secondary Sealing Elements二次密封,Pusher推进式,Non-Pusher非推进式,O-ring secondary seal must slide along shaft as seal face wearsO型圈二次密封在密封面磨损的时候必须能够沿轴滑动,Bellows secondary sealexpands to accommodateface wear.Bellows tail is stationary agai
15、nst shaft.波纹管伸长能够补偿密封面磨损,波纹管尾部与轴保持静止,vs.,Pusher vs.Non-Pusher推进式/非推进式,25,Secondary Seal:Pusher二次密封：推进式,As the face moves forward to take up wear,the o-ring moves forward with the face,pushed by the hydraulic and spring pressures,26,Secondary Seal:Pusher二次密封：推进式,Advantages 优点sudden failure very unlik
16、ely 几乎不会突发意外事故higher pressure capability-face not stressed 耐压性能高-应力变形小wide choice of materials for all components 所有成分的材料选择广泛field repairable可修复的Disadvantages 缺点hang-up(not likely where o-ring is well isolated)挂起permanent set/pressure problems(cause hang-up)长久放置/压力问题（导致挂起）excellent shaft surface fin
17、ish required要求轴的表面光滑maximum temperature+260C 最高温度+260C,27,Pusher Seal:Hang-up推进式密封：挂起,Product leakage solidifies/crystallises/polymerises,Prevents o-ring pushing forward-leakage increases阻止O形圈迅速的推进-泄漏增加,An external quench will prevent hang-up外部的冲洗可防止挂起,28,Secondary Seal:O-Ring二次密封：O型圈,Type 8B1,29,Se
18、condary Seal:Wedge二次密封：楔形环,30,Secondary Seal:Non-Pusher二次密封：非推进式,Bellows flexes to take up wear,misalignment and axial play,Fine machined shaft surface required精掣轴表面Do not use a good lubricant-never use silicon grease,31,Secondary Seal:Bellows二次密封：波纹管,32,Secondary Seal:Metal Bellows二次密封：金属波纹管,static
19、 o-ring静止o型圈,33,Type 10T,Type 10R,Secondary Seal:PTFE Bellows二次密封：PTFE波纹管,Tertiary Seal 三次密封,35,Tertiary Seal 三次密封,Prevents leakage round mating ring 防止静环周围的泄漏Sometimes also prevents mating ring rotation有时也防止静环旋转,36,Tertiary Seal 三次密封,Four basic types 四种基本的形式O-rings O型圈Elastomers 橡胶Seat Rings(square
20、 or rectangular section)PTFEgraphiteCup RingselastomersGaskets or Flat JointsPTFEcompressed fibre非石棉的压缩纤维,Tertiary Seal:O-ring三次密封：O型环,Tertiary Seal:O-ring三次密封：O型环,Tertiary Seal:O-ring三次密封：O型环,40,Tertiary Seal:Seat Ring三次密封：静环,Tertiary Seal:Cup Rubber三次密封：,Spring Design Features 弹簧设计特点,Springs 弹簧Pro
21、vide The Initial Closing Force提供初始闭合力Are Very Important At Low Pressures低压下很重要Are Not So Important At High Pressures高压下不重要,Design Features 设计特点,Springs 弹簧Single 单弹簧Multiple 多弹簧Bellows 波纹管Wave 波形,Design Features 设计特点,Springs 弹簧High Speed Seals Use Stationary Springs(5000 ft/min Typical Break Point)高速
22、机械密封使用静止弹簧(5000ft/min 典型的分界点),Design Features 设计特点,Springs 弹簧Corrosion 腐蚀Clogging 堵塞Uniformity Of Load 负荷一致Inventory 批量,Drive Mechanism 驱动机械Must Transmit Torque 必须能够传递转矩Must Allow Axial Movement(Primary Ring)必须能够使动环轴向运动,Types of Drive Mechanisms 驱动机械的类型,Pin Drive 销驱动,Dent Drive凹窝驱动,Slot and Ear槽和支耳,
23、Spring Drive弹簧驱动,Set Screw Drive定位螺丝驱动,Snap Ring Drive卡环驱动,Elastomer Drive橡胶驱动,Key Drive键驱动,Types of Drive Mechanisms 驱动机械的类型,48,Seal Materials 密封材料,Material Considerations 材料需要考虑Temperature 温度Thermal Expansion 热膨胀Thermal Conductivity 导热性Chemical Resistance化学稳定性Wear 磨损性Flexibility 弹性Manufacturabilit
24、y 制造能力Cost 成本Availability 实用性,49,Primary Seal Materials主密封材料,Face(Primary Ring-Narrow)Materials 窄环材料Carbon-graphite 炭-石墨 resin impregnated 浸渍树脂antimony impregnated 浸渍金属锑Carbon converted to Silicon Carbide 硅化石墨,50,Primary Seal Materials主密封材料,Carbon converted toSilicon Carbide,51,Solid Silicon Carbide
25、碳化硅 pure sintered 常压烧结 reaction bonded 反映烧结 Tungsten Carbide 硬质合金 nickel or cobalt bonded.镍基或钴基,Primary Seal Materials主密封材料,52,Primary Seal Materials主密封材料,Seat(Mating Ring)Materials 静环材料 Solid Silicon Carbide碳化硅 pure sintered 常压烧结 reaction bonded 反映烧结 Tungsten Carbide 硬质合金 nickel or cobalt bonded.镍基
26、或钴基Ni-resist 高镍铸铁high nickel cast iron;austenitic cast iron奥氏体铸铁Ceramic 陶瓷99.7%aluminium oxide 99.7%氧化铝,53,Primary Seal Materials主密封材料,ceramic mating ring,54,Material Properties 材料性质,Buna-N,EPDM,VitonTM,-54癈/-65癋,149癈/300癋,121癈/250癋,-240癈,-129癈,-18癈,204癈,316 C,93癈,AflasTM,204癈/400癋,204癈/400癋,-45癈/-50癋,-29癈/-20癋,TeflonTM,287癈/550癋,-212癈/-350癋,-29癈/-20癋,KalrezTM,287癈/550癋,-40癈/-40癋,Secondary Sealing Elements Temperature Range二次密封温度范围,56,Seal Materials 密封材料,Parker O-Ring Compatibility Table,
