Heat pump seal the main problems: (1) the use of the existing mechanical seal and its auxiliary system, high temperature pump in the process of operation, variable operating conditions occur from time to time. Pump pumping, misuse, man-made flow regulation so that the mechanical seal is in variable working conditions. When the pressure of the sealing medium fluctuates violently, it can cause mutual impact of the friction pairs and damage the end faces, which will affect the sealing effect. If the sealing chamber pressure fluctuates and instantly becomes negative pressure, the bellows shrinks and can not recover in time. The dynamic and static friction Vice film between the formation of the oil seal is damaged caused by sudden leakage failure. (2) The working medium temperature is very high, together with the frictional heat of the seal friction end face, once the flushing system breaks down, the temperature of the end face rises sharply, resulting in the dry friction caused by vaporization of the end liquid film and the seal failure in a short time; Secondly, the high temperature can also degrade the performance of the graphite ring, and can melt the impregnating agent in severe cases. Thirdly, when the static and dynamic ring material is matched with tungsten carbide and graphite, the high temperature can also cause annular grooves on the surface of the graphite ring, Tungsten carbide (moving ring) is also easy to fall off; finally, the frictional heat distortion under high temperature causes the friction state of the end surface to change, leading to the early failure of the sealing system. (3) high operating costs, energy consumption.