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 There are many types of shaft seals to prevent leakage. Because mechanical seals have the advantages of less leakage and long life, mechanical seals are the most important shaft sealing method in these equipment in the world.