Functions of Mechanical Seal Element

Mechanical seal, to be exact, rotary mechanical end face seal is a kind of axial sealing device, which is achieved by preloading the static and dynamic ring end friction pairs by elastic elements and compressing the medium pressure and elastic element pressure.

The function of the basic components of the mechanical seal is as follows:

(1) the end friction pairs (dynamic and static rings) keep close contact with each other to form a mechanical seal surface to prevent medium leakage. It is required that the dynamic and static rings have good wear resistance, the dynamic ring can move axially and automatically compensate for the wear of the sealing surface, so that it fits well with the static ring, and the static ring has floatability and buffering effect.

(2) The elastic elements (spring, corrugated plate, serpentine sleeve, etc.) mainly play the role of compensation, pre-tightening and buffering and they are also the factors that produce reasonable specific pressure on the seal face. It is required to always maintain the elasticity to overcome the friction between the auxiliary seal and the transmission parts and start the compensation function of the ring.

(3) Auxiliary seals (0-ring, V-ring, wedge-shaped rings and other special-shaped mechanical seal ring) mainly play the sealing role of static ring and dynamic ring, they also play the role of floating and buffering. It is required that the auxiliary sealing elements of static ring ensure the sealing between static ring and gland, so that the static ring has a certain floating; the auxiliary sealing elements of dynamic ring ensure the sealing between dynamic ring and shaft or shaft sleeve. Material requirements Heat and cold resistance are close to the medium.

(4) Transmission parts (transmission pin, transmission ring, transmission seat, transmission sleeve, transmission key, transmission lug or jaw type coupling), whose function is to transmit the torque of shaft to the transmission ring. The material should be corrosion-resistant and wear-resistant.

(5) The fixing parts (set screw, spring seat, gland, assembly sleeve and shaft seal sleeve) play the role of positioning and tightening of static and dynamic rings. It is required to be correctly positioned to ensure that the sealing surface of friction pair is in the correct position and maintain a good spring pressure; at the same time, it is required to be convenient for disassembly and assembly, easy to be in place, and can be reused. Pay attention to the chamfering and pressure elasticity of the installation sealing ring at the fitting place with auxiliary seal. Special attention should be paid to the joint between the moving ring seal ring and the shaft sleeve, which should be with corrosion-resistance and wear-resistance. If necessary, the hard surface coating should be adopted.