Mechanical seals are very important devices in industry and have played an important part in indutry development and processing.

According to industrial fields mechanical seals are required and applied in transportation manufactuing industry, household appliances, power generating machinery, chemical industry, petrolchemical industry, National defense industry, ship-manufactuing, etc.

According to the devices or equipment, mechanical seals are required and applied in varieties of pumps, reactive kettles, centrifugal machines, blowers, boilers, agitators, frezzers,submersible machines, internal combustion engines,cooling water pumps,ship pumps etc.

According to the functions and constructures mechanical seals can be divided into single end-face mechanical seals, double end face mechanical seals, multiple end face mechanical seals and mechanical seals can be axial and radial mechanical seals.

According to pressures mechanical seals can be divided into unbalanced mechanical seals, partially balalnced mechanical seals, complete balance mechanical seals.

According to the stationary part position mechanical seals can be divided into bulit-in-fluid mechanical seals and built-out-of fluid mechanical seals.

According to springs, mechanical seals can be divided into single spring mechanical seals, multiple sping mechanical seals

According to spring designs, mechanical seals can be divided into coil spring mechanical seals, wave spring mechanical seals

According to modes of leakage mechanical seals can be flowing-out mechanical seals and flowing-in mechanical seals.

According to bellows mechanical seals have non-bellow mechanical seal and bellow mechanical seals.Bellow mechanical seals can be classified into metal bellow mechanical seals, rubber bellow mechanical seals, PTFE bellow mechanical seals. Metal bellow mechanical seals can be divided into welded metal bellow mechancial seals, formed metal bellow mechanical seals.

According to temperatures mechanical seals can be divided into high temperature mechanical seals(more than 200 ℃, medium temperature mechanical seals(80 ℃-200 ℃), normal temperature mechanical seals(-50 ℃-80 ℃), low temperature mechanical seals(less than -50℃).

According to pressures, mechanical seals can be divided into super-pressure mechanical seals(more than 15 Mpa),high pressure mechanical seals(5-15 Mpa),medium pressure mechanical seals(0.8-5 Mpa), normal pressure mechanical seals(0.8Mpa),low pressure mechanical seals. When pressure is minus mechanical seals are used in vacumme.

According to velocity, mechanical seals can be claasified into super-speed mechanical seals(100m/s),high speed mechanical seals(30-100 m/s),medium speed mechanical seals(2.5-30 m/s),low speed mechanical seals(2.5m/s)

According to fluids with grains or not, mechanical seals can be used in grain fliuds and fluids without grains

According to chemical property of fluids, mediums can be divided into corrosive fluids, oil, water, and general mediums

According to inside diameters mechanical seals can be classified into large diameter mechanical seals( more than 120mm),general diameter mechanical seals(25-120mm) and small diameter mechanical seals(25mm)

According to pressures,temperatures, velocity and inside diameters mechanical seals can be classified into heavy duty mechanical seals(pressure≥5Mpa, temperatures-50℃-200℃, speed ≥30m/s, inside diameter≥120mm),mediu duty mechanical seals(0.5 Mpa≤P≤5Mpa, -50℃-200℃,10m/s≤V≤30m/s, inside diameter:25-120mm),light duty mechanical seals(P less than 5 Mpa, 0℃-80℃, V less than 10 m/s, diameter less than 25mm)