The main reasons of sealing failure of O-ring are as below:
1. The design of the sealing groove is unreasonable.
2. The O-ring is incompatible with the used medium.
3. The size of the O-ring is not selected correctly.
4. The O-ring is not sufficiently lubricated.
In addition, due to the complexity of force of the sealing ring, it is difficult to diagnose and judge for some reasons, and it is necessary to conduct experimental research on its material and environment.