Mechanical seal (mechanical seal) refers to at least a pair of end surfaces perpendicular to the axis of rotation under the action of fluid pressure and the elastic force (or magnetic force) of the compensation mechanism and the auxiliary seal to keep fit and slide relative to prevent fluid leakage. Device.

The elastic loading mechanism and the auxiliary seal are the mechanical seals of the metal bellows, which we call the metal bellows seal. In light-duty seals, rubber bellows are also used as auxiliary seals. Rubber bellows have limited elasticity and generally need to be supplemented with springs to meet the loading elasticity. "Mechanical seal" is often referred to as "mechanical seal" for short.

Mechanical seal is a shaft sealing device for rotating machinery. Such as centrifugal pumps, centrifuges, reactors and compressors and other equipment. Since the drive shaft runs through the inside and outside of the equipment, there is a circumferential gap between the shaft and the equipment, and the medium in the equipment leaks outward through the gap. If the pressure in the equipment is lower than the atmospheric pressure, the air leaks into the equipment, so there must be a Shaft seal to prevent leakage. There are many types of shaft seals. Because mechanical seals have the advantages of less leakage and long life, mechanical seals are the important shaft seal method for these equipment in the world. Mechanical seal is also called end face seal. It is defined in relevant national standards as follows: "At least a pair of end faces perpendicular to the axis of rotation are kept close together under the cooperation of fluid pressure and the elastic force (or magnetic force) of the compensation mechanism and the auxiliary seal. A device that prevents fluid leakage by sliding relative to each other."