What are the causes of mechanical seal leakage in multi-stage centrifugal pump operation?

1.The sealing end faces are not parallel.

2.The shaft or sleeve is worn.

3.The pump shaft is bent.

4.The end faces of dynamic and static sealing rings are corroded, worn or scratched.

5.The static ring assembly is tilted.

6.The spring pressure is insufficient.

7.The axial movement is too large.