First, the principle of mechanical seal
Anyone who processes mechanical parts knows that mechanical seals are also called end face seals. Its main function is to change the easy-to-leak axial seal to the more difficult-to-leak end face seal, which is actually a shaft seal device for rotating machinery. Under the action of the liquid pressure and the elastic force (or magnetic force) of the compensation mechanism and the cooperation of the auxiliary seal, the mechanical seal is composed of at least a pair of end faces perpendicular to the rotation axis, which are kept in contact and relatively sliding to prevent fluid leakage. It is currently widely used in the sealing of rotating shafts of pumps, kettles, compressors and other similar equipment.
Second, the role of mechanical seals
Mechanical seals usually consist of a moving ring, a static ring, a compression element and a sealing element. The moving ring and the static ring closely fit together to form a sealing surface, and the moving ring rotates with the pump shaft to prevent medium leakage. The moving ring relies on the pressure of the liquid in the sealing chamber to press its end face against the end face of the static ring, and generate an appropriate specific pressure on the end faces of the two rings and maintain a very thin liquid film to achieve the purpose of sealing.
The sealing element plays the role of sealing the gap between the moving ring and the shaft, the gap between the static ring and the gland, and the elastic element plays a buffering role in the vibration and impact of the pump. The compression element generates pressure, which can keep the end face of the pump in non-operational state, ensure that the sealing medium does not leak out, and prevent impurities from entering the sealing end face.
The normal operation of the mechanical parts seal has a great relationship with its own performance and external conditions. In actual operation, the mechanical seal operates in combination with other parts of the pump. However, we must first ensure the technical requirements of our own parts performance, auxiliary sealing device and installation, so that the mechanical seal can play its due role.
3. What are the manifestations of mechanical seal failure
The mechanical seal vibration, heating and other faults will make the dynamic and static rings fit rough ends during the rotation of the equipment, and the gap between the dynamic and static rings and the sealing cavity is too small, which will cause vibration due to collision caused by vibration. Sometimes due to the poor corrosion resistance and temperature resistance of the sealing end face, or insufficient cooling or particle impurities on the end face during installation, it will also cause vibration and heat of the mechanical seal.
Failure of mechanical seal parts During the operation of rotating equipment, the seal end face often occurs wear, thermal cracking, deformation, damage, etc., and the spring will relax, break and corrode after a long time. Auxiliary seals can also be cracked, twisted and deformed, cracked, etc.
Looking forward to your consultation if there is anything unclear