机械密封知识

Mechanical seal knowledge

一、机械密封概述

1、 Overview of mechanical seal

机械密封（端面密封）是一种用来解决旋转轴与机体之间密封的装置。它是由至少一对垂直于旋转轴线的端面的流体压力和补偿机构弹力（或磁力）的作用及辅助密封的配合下保持贴合下并相对滑动而构成防止流体泄漏的装置，常用于泵、压缩机、反应搅拌釜等旋转式流体机械，也用于齿轮箱、船舶尾轴等密封。因此，机械密封是一种通用的轴封装置。

Mechanical seal (face seal) is a device used to solve the problem of sealing between the rotating shaft and the body. It is composed of at least one pair of fluid pressure perpendicular to the end face of the rotating axis, the effect of the elastic force (or magnetic force) of the compensation mechanism and the cooperation of the auxiliary seal to keep the joint and relatively slide, thus forming a device to prevent fluid leakage. It is commonly used in rotary fluid machinery such as pumps, compressors, reaction agitators, and also used for sealing of gear boxes, ship tail shafts, etc. Therefore, mechanical seal is a kind of general shaft seal device.

机械密封结构多种多样，最常用的机械密封结构是端面密封。端面密封的静环、动环组成一对摩擦副，摩擦副的作用是防止介质泄漏。它要求静环、动环，具有良好的耐磨性，动环可以在轴向灵活的移动，自动补偿密封面磨损，使之与静环良好的贴合；静环具有浮动性，起缓冲作用。

There are many kinds of mechanical seal structures, the most commonly used mechanical seal structure is the face seal. The static ring and the moving ring of the end face seal form a pair of friction pairs, whose function is to prevent medium leakage. It requires the static ring and the dynamic ring, which have good wear resistance. The dynamic ring can move flexibly in the axial direction, and automatically compensate the wear of the sealing surface, so that it fits well with the static ring; the static ring has floatability, and plays a buffer role.

为此，密封面要求有良好的加工质量，保证密封副有良好的贴合性能。构成机械密封的基本元件有静环、动环、压盖、推环、弹簧、定位环、轴套、动环密封圈、静环密封圈轴套密封圈等。

Therefore, the sealing surface requires good processing quality to ensure that the sealing pair has good adhesion performance. The basic components of mechanical seal include static ring, dynamic ring, gland, push ring, spring, locating ring, shaft sleeve, dynamic ring seal ring, static ring seal ring, shaft sleeve seal ring, etc.

弹性元件（弹簧、波纹管）它主要起预紧、补偿和缓冲的作用，要求始终保持足够的弹性来克服辅助密封和传动件的摩擦和动环等的惯性，保证端面密封副良好的贴合和动环的追随性，材料要求耐腐蚀、耐疲劳。

Elastic components (spring, bellows) mainly play the role of pre tightening, compensation and buffering. It is required to always maintain enough elasticity to overcome the friction of auxiliary seal and transmission parts and the inertia of moving ring, so as to ensure a good fit of end seal pair and the following performance of moving ring. The material is required to be corrosion-resistant and fatigue resistant.

辅助密封（0 形圈、V形圈、U 形圈、楔形圈和异形圈等）它主要起静环和动环的密封作用，同时也起到浮动和缓冲作用。要求静环的密封元件能保证静环与压盖之间的密封性，静环有一定的浮动性，动环的密封元件能保证动环与轴或轴套之间的密封性和动环的浮动性。材料要求耐热等。

Auxiliary seal (0-ring, V-ring, U-ring, wedge-shaped ring and special-shaped ring, etc.) mainly plays the sealing role of static ring and dynamic ring, and also plays the role of floating and buffering. It is required that the sealing element of the static ring can ensure the sealing between the static ring and the gland, the static ring has a certain degree of floating, and the sealing element of the dynamic ring can ensure the sealing between the dynamic ring and the shaft or the shaft sleeve and the floating of the dynamic ring. Materials shall be heat resistant, etc.