机械密封件属于精密、结构较为复杂的机械基础元件之一，是各种泵类、反应合成釜、透平压缩机、潜水电机等设备的关键部件。其密封性能和使用寿命取决于许多因素，如选型、机器的精度、正确的安装使用等。
Mechanical seal is one of the basic mechanical components with high precision and complex structure. It is the key component of various pumps, reactor, turbine compressor, submersible motor and other equipment. Its sealing performance and service life depend on many factors, such as type selection, accuracy of the machine, correct installation and use, etc.
1、机械密封的基本概念
1. Basic concept of mechanical seal
机械密封是指由至少一对垂直于旋转轴线的端面在流体压力和补偿机构弹力（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的防止流体泄漏的装置。补偿环的辅助密封为金属波纹管的称为波纹管机械密封。
Mechanical seal is a device to prevent fluid leakage, which is composed of at least one pair of end faces perpendicular to the rotating axis, under the action of fluid pressure and the elastic force (or magnetic force) of the compensation mechanism and the cooperation of auxiliary seals. The auxiliary seal of compensation ring is metal bellows, which is called bellows mechanical seal.
2、机械密封的组成
2. Composition of mechanical seal
主要有以下四类部件。a.主要密封件：动环和静环。b.辅助密封件：密封圈。c.压紧件：弹簧、推环。d.传动件：弹箕座及键或固定螺钉。
There are mainly four types of parts. a. Main seals: moving ring and stationary ring. b. Auxiliary seal: seal ring. c. Compression piece: spring, push ring. d. Transmission parts: skip seat and key or fixing screw.