The mechanical seal (end face seal) is a device used to solve the sealing between the rotating shaft and the body. It is composed of at least a pair of fluid pressure perpendicular to the end face of the rotating axis, the action of the compensating mechanism elastic force (or magnetic force) and the coordination of the auxiliary seal to keep fit and slide relative to each other to prevent fluid leakage. It is commonly used in rotary fluid machinery such as pump, compressor, reaction stirring kettle, etc., and also used for sealing of gearbox and ship stern shaft, etc. Therefore, mechanical seal is a universal shaft seal device. The mechanical seal ring is an important sealing element in the field of mechanical seal.
Mechanical seal structure is various and the most commonly used mechanical seal structure is the end seal. The mechanical seal ring
for the end face comprises a static ring and a moving ring to form a pair of friction pairs. The function of friction pair is to prevent medium leakage. It requires the static ring, moving ring, with good wear resistance. Moving ring can be flexible in the axial movement, automatic compensation sealing surface wear, making it have a good fit with the static ring. The static ring is buoyant and acts as a buffer. For this reason, the sealing surface requires good processing quality to ensure that the sealing pair has good fitting performance. The basic components of mechanical seal are mechanical seal ring (mainly static ring and moving ring), gland, push ring, spring, positioning ring, shaft sleeve, moving ring seal ring, shaft sleeve seal ring, etc.
Elastic element (spring, bellows) mainly plays the role of preload, compensation and buffer. It is required to always maintain enough elasticity to overcome the friction of the auxiliary seal and transmission parts and inertia of the moving ring, etc., so as to ensure the good fitting of the end face sealing pair and the following of the moving ring. Corrosion resistance and fatigue resistance are required for materials.
Auxiliary seal (0 ring, V ring, U ring, wedge ring and special-shaped ring, etc.) mainly plays the role of static ring and moving ring seal, but also plays a floating and buffering role. The sealing elements of the stationary ring in the mechanical seal ring are required to ensure the sealing between the stationary ring and the gland. The static ring has a certain buoyancy, and the sealing element of the moving ring can ensure the sealing between the moving ring and the shaft or shaft sleeve and the buoyancy of the moving ring. Material is required to have heat resistance, etc.