Analysis of Common Failure Phenomena of Mechanical Seals1

The actual use results show that the most failure parts of mechanical seal sealing elements are the dynamic and static ring end faces, the centrifugal pump seal is dynamic, and the cracks on the static ring end face are common failure phenomena. The main reasons are:

①During installation, the clearance of the sealing surface is too large, and the flushing fluid cannot take away the heat generated by the friction pair; the flushing fluid leaks from the clearance of the sealing surface, causing the end face to be overheated and damaged.

②The liquid medium vaporizes and expands, so that the two end faces are separated by the vaporizing expansion force. When the two sealing surfaces are forced to fit together, the lubricating film is destroyed and the end surface surface is overheated.

③The lubricity of the liquid medium is poor, and the operating pressure is overloaded, so the tracking and rotation of the two sealing surfaces are not synchronized. For example, the speed of the high-speed pump is 20445r/min, the diameter of the sealing surface is 7cm, and the linear speed of the pump is as high as 75m/s after running.

④The orifice plate or filter screen of the sealing flushing fluid is blocked, resulting in insufficient water volume and invalidating the mechanical seal.