Knowledge points of polypropylene storage tanks: overview of mechanical seals of mechanical seal knowledge

Knowledge points of polypropylene storage tanks: overview of mechanical seals of mechanical seal knowledge

Mechanical seal (face seal) is a device used to solve the sealing between the rotating shaft and the body. It is a device that prevents fluid leakage by the action of at least one pair of end faces perpendicular to the rotation axis, the elastic force (or magnetic force) of the compensation mechanism, and the cooperation of auxiliary seals to keep fit and slide relative to each other to prevent fluid leakage. Rotary fluid machinery such as compressors, reaction stirring tanks, etc., and also used for sealing of gearboxes, ship tail shafts, etc. Therefore, the mechanical seal is a universal shaft sealing device.
There are various mechanical seal structures, and the most commonly used mechanical seal structure is the end face seal. The static ring and the moving ring of the end face seal form a pair of friction pairs, and the function of the friction pairs is to prevent the leakage of the medium. It requires the static ring and the moving ring to have good wear resistance. The moving ring can move flexibly in the axial direction and automatically compensate for the wear of the sealing surface, so that it fits well with the static ring; the static ring has a floating property and acts as a buffer. . For this reason, the sealing surface requires good processing quality to ensure that the sealing pair has good fit performance. The basic elements that constitute the mechanical seal are static ring, moving ring, gland, push ring, spring, positioning ring, shaft sleeve, moving ring sealing ring, static ring sealing ring, shaft sleeve sealing ring, etc.
The elastic element (spring, bellows) mainly plays the role of preloading, compensation and buffering. It is required to always maintain sufficient elasticity to overcome the friction of auxiliary seals and transmission parts and the inertia of the moving ring, etc., to ensure a good fit of the end face seal pair. And the followability of the moving ring, the material requires corrosion resistance and fatigue resistance.
Auxiliary seals (O-rings, V-rings, U-rings, wedge-shaped rings and special-shaped rings, etc.) mainly play the role of sealing the static ring and the moving ring, and also play the role of floating and buffering. The sealing element of the static ring is required to 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 moving ring can ensure the sealing between the moving ring and the shaft or the shaft sleeve and the sealing of the moving ring. Floatability. Materials are required to be heat-resistant, etc.
1. Basic structure
1) End face seal friction pair
2) Buffer compensation and compression mechanism
3) Auxiliary seal (secondary seal flexible element)
4) Transmission mechanism
2. Basic sealing point
1) The main sealing point of the end face
2) Auxiliary sealing point between static ring and end cover
3) Auxiliary sealing point between the moving ring and the shaft (sleeve)
4) The sealing point connecting the end cover and the pump body