stationary elements在旋转件和 静止件之间形成很薄的液膜
SPRING FORCE
FLUID PRESSURE
fluid film (3 - 5 microns)
13
Primary Seal – Film Thickness
主密封——膜厚度
Faces lapped flat to within 1 - 3 light bands. 14
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
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
Basic Mechanical Seal
基础机械密封 1
Loose ring set screwed to the shaft
把一个有间隙的环用顶丝固定在轴上
4
Basic Mechanical Seal
基础机械密封
2
Wear here will create leakage 这里的磨损将导致泄漏
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 时机械密封可以提供更 12 好的安全性
FILM REACTION
Primary Seal 主密封
a thin film of liquid forms the primary (dynamic) seal between the rotating and
Basic Mechanical Sining
1
What is a mechanical seal?
什么是机械密封？
two flat sliding surfaces, which maintain a close running clearance while separated by a fluid film
Secondary Seal
Tertiary Seal
Primary Seal 9
Complete Seal一个完整密
封的例子
Primary Ring补偿环
Snap Ring卡环
Anti-X Ring 挡环 O-Ring O型圈
Disk推环 Springs弹簧
Retainer传动套 Set Screw定位螺丝
两个光滑平面之间维持着一个由流体膜隔开的微小间隙
rotating seal unit stationary seal unit
2
Seal
机械密封必须有的特征
Small axial clearance 小的轴向间隙 Self adjusting 自调节
Shaft Movement 轴的运动
Long-life 很长的寿命 Easy maintenance 容易检修 Low cost 低成本
基础机械密封
Sea5l
Spring or Spring Force
Seat or Mating Ring
Face or Primary Ring
8
Basic Mechanical Seal
基础机械密封
SPRING OR SPRING FORCE
Recirculation for cooling
Gasket or O-ring SEAT
acceptable pressure允许的压力
15
Primary Seal – Face Flatness
主密封——平面
If faces not flat, contact generates heat Excessive wear - short life
1 light band = 0.0000116 inch or 0.0003 mm
3. A secondary sealing element 二次密封
4. A mechanical loading device to press 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
Gland Packing v. Mechanical Seals 盘根和机械密封
Primary Seal – Film Thickness
Flui主d fi密lm 封thic—kne—ss膜is 厚ver度y important
too thin - wear, causing early seal failure too thick - visible leakage
Must be:
present - beware dry running谨防干运转
Stable稳定
谨防磨损征兆
clean - beware abrasive wear symptoms
reasonable viscosity合理的黏度
temperature controlled受控的温度
O-ring prevents leakage through the bore
5
Basic Mechanical Seal
基础机械密封 3
Leak path Heat generated here 此处生热
Large component 大零件
Spring ensures automatic adjustment
弹簧确保自动调整
6
Basic Mechanical
基础机械密封
Seal4
Recirculation for cooling
Gasket or O-ring 垫片或者O型圈
Secondary Seal
Tertiary Seal
二次密封
Primary Seal 三次密封
7
主密封
Basic Mechanical
O-Ring O型圈
Mating Ring 配合环
Shaft轴
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