In mechanical seals, the main wear part is the seal friction end face, because the wear amount of the seal end face is not large under normal working conditions, such as the graphite friction pair with a balance coefficient of 0.75, the wear per hour in water and engine oil is about 0.1 Micron, that is to say, the wear of about 10,000 hours of continuous operation is about 1 mm. It can be seen that the wear of the friction pair generally does not affect the life of the mechanical seal.
Mechanical seals can generally be used continuously for 1 ~ 2 years. In some cases, they can be used for 5 ~ 10 years. There is no problem. Japan JIS B2405-77 "General Specification for Mechanical Seals" stipulates that, generally, the life of general mechanical seals requires a minimum of 1 year of use, but it is not subject to this limit under harsh conditions and high operating rates and frequent start-ups; API682 "Centrifugal Pumps and Rotor Pumps "Seal System" stipulates that the seal life is 3 years. The above-mentioned service life premise is that the mechanical seal operates under the allowable working conditions, such as shaft movement, runout, medium particle concentration, temperature, corrosion and other factors.