Mechanical seal is also called end surface seal. It is a shaft seal device for rotating machinery, which refers to the end surface that is perpendicular to the rotating axis. The device that prevents fluid leakage. Its main function changes the axial seal of the leakage to the end surface seal that is difficult to leak. It is widely used in the seal of the rotating axis of pumps, kettles, compressors and similar devices. Mechanical sealing is usually composed of dynamic ring, static ring, tight component and seal element. Among them, the dynamic ring rotates with the pump axis, and the moving ring and the static ring are tightly fits the cover to prevent the medium leak. The pressure of the liquid in the sealing room is pressed on the end surface of the static ring, and the proper pressure is generated on the ends of the two rings and maintained a layer of extremely thin liquid membrane to achieve the purpose of the seal. The pressure of tight components can cause pressure, which can keep the pump in the state of not running, and keep the end face fit to ensure that the sealing medium is not leaked, and prevents impurities from entering the sealing end surface. The gap between the sealing ring and the shaft in the sealing element, the effect of the gap between the static ring and the cover cover, at the same time, the elastic element on the vibration of the pump, impacts the buffer effect. The mechanical seal is combined with other parts of the pump in actual operation. The normal operation of the mechanical seal has a lot to do with its own performance and external conditions. However, we must first ensure our own parts performance, auxiliary sealing device and installation technical requirements, so that the mechanical sealing can exert its due role.