What are the reasons for leakage failure of O-rings using mechanical seals?

What are the reasons for the leakage failure of the mechanical seal O-ring
　　
Leakage during installation static test.
After the mechanical seal is installed and debugged, a static test is generally performed to observe the leakage. If the amount of leakage is small, there is usually a problem with the moving or static ring sealing ring; when the amount of leakage is large, it indicates that there is a problem between the moving and static ring friction pairs. On the basis of the preliminary observation of the leakage and the judgment of the leakage position, the manual cranking observation is carried out. If the leakage does not change significantly, the static
There is a problem with the moving ring seal; if there is a significant change in the leakage during cranking, it can be concluded that there is a problem with the dynamic and static ring friction pairs; if the leakage medium is sprayed in the axial direction, the moving ring seal is mostly defective, and the leakage medium is around Spray or leak from the water cooling hole, mostly static ring seal failure. In addition, leakage channels can also exist at the same time, but there are generally primary and secondary differences. As long as you observe carefully and are familiar with the structure, you will be able to make a correct judgment.
　　

Leaks occurred during trial operation.
After the mechanical seal for the pump has undergone static testing, the centrifugal force generated by the high-speed rotation during operation will inhibit the leakage of the medium. Therefore, the mechanical seal leakage during the trial operation is basically caused by the damage of the dynamic and static ring friction pairs after the failure of the shaft and the end cover seal is eliminated.
Sudden power failure or downtime, etc.
If the centrifugal pump leaks suddenly during normal operation, if it can not be found in time, it will often lead to larger accidents or losses, which must be taken seriously and effective measures should be taken.
Especially for accidents caused by sudden power failure, you must make a good power supply O-ring.