What are the main types of mechanical seals? Machinery Seal

What are the main types of mechanical seals?

2021-08-19 10:13

Mechanical seals are a general term for the basic components of precision machinery. They are favored by the public because they can rotate in any direction, have small spring layouts, short axial dimensions, and even pressure on the sealing end faces. However, it is often troubled by people in terms of installation and disassembly. Let me introduce the precautions for installation and disassembly of mechanical seals.

1. The basic concept of mechanical seal

A mechanical seal refers to a device that prevents fluid leakage by at least one pair of end faces perpendicular to the torsion axis that are held together and relatively slid under the action of fluid pressure and the elastic force (or magnetic force) of the compensation mechanism and the cooperation of the auxiliary seal. The auxiliary seal of the compensation ring is a metal bellows called a bellows mechanical seal.

2. Composition of mechanical seals

There are mainly the following four types of components. a. Main seals: moving ring and static ring. b. Auxiliary seal: sealing ring. c. Compression parts: spring, push ring. d. Transmission parts: skip seat and key or fixing screw.

3. Matters needing attention when installing mechanical seals

(1) Pay great attention to avoid installation deviation during installation

a. Tightening the gland should be done after the alignment of the coupling. The bolts should be evenly supported to prevent the end face of the gland from deflecting. Check each point with a feeler gauge, and the error should not be greater than 0.05mm.

b. Check the fit clearance (that is, concentricity) between the gland and the outer diameter of the shaft or bushing. The surroundings should be even. Use a feeler gauge to check that the tolerance of each point is not more than 0.01 mm.

(2) The amount of spring compression should be carried out according to the regulations, and no excessive or small phenomenon is allowed, and the error is required to be 2.00mm. If it is too large, the specific pressure of the end face will be increased, and the end face will be worn at a faster rate. Too small will result in insufficient specific pressure and cannot play a sealing role.

(3) After the moving ring is installed, the pipe must be able to move flexibly on the shaft, and it should spring back automatically after pressing the moving ring to the spring.