(1) The multi-stage oil pump adopts the existing mechanical seal and its auxiliary system. During the operation of the high-temperature oil pump, the operation of the variable working condition occurs. Pump pumping, misoperation, and manual flow adjustment all make the mechanical seal under variable operating conditions. When the pressure of the sealing medium fluctuates drastically, it may cause mutual impact of the friction pair, causing damage to the end surface, thereby affecting the sealing effect; if the operating pressure of the sealing chamber fluctuates and instantaneously becomes a negative pressure, the bellows shrinks and cannot be recovered in time, dynamic and static friction The oil film seal formed between the secondary sides is destroyed to cause sudden leakage failure.
(2) The working medium temperature is very high, coupled with the friction heat of the sealing friction end face. Once the flushing system fails, the end face temperature rises sharply, causing the inner surface liquid film to vaporize and causing dry friction, which can invalidate the seal in a short time; Secondly, the high temperature can also reduce the performance of the graphite ring, and in the severe case, the impregnating agent can be melted; again, when the dynamic and static ring material is paired with tungsten carbide and graphite, the high temperature can also cause an annular groove on the surface of the graphite ring (static ring). Tungsten carbide (dynamic ring) is also easy to fall off; finally, the frictional pair has a large thermal deformation at high temperature, which causes the friction state of the end face to change, leading to premature failure of the sealing system.
(3) High operating costs and large energy consumption.
