Factors causing failure of mechanical seals for pumps

During the use of mechanical seals for pumps, there are many reasons that will lead to product failure, which seriously affects the use of the product. In this regard, in order to avoid these products, the following will introduce the factors of equipment failure.

1. During operation, due to abnormal phenomena such as evacuation, cavitation, and pressure holding, a large axial force is caused to separate the contact surface of the dynamic and static rings;

2. When the mechanical seal is installed, the compression amount is too large, resulting in severe wear and abrasion on the end face of the friction pair;

3. The sealing ring of the moving ring is too tight, and the spring cannot adjust the axial floating amount of the moving ring;

4. The sealing ring of the static ring is too loose. When the moving ring floats axially, the static ring will break away from the seat of the static ring;

5. There are granular substances in the working medium, which enter the friction pair during operation, and detect the dynamic and static ring sealing end faces;

6. Incorrect design and selection, low specific pressure of the sealing end face or high cold shrinkage of the sealing material, etc. The above phenomenon often occurs during trial operation, and sometimes it can be eliminated by properly adjusting the static ring seat, etc., but most of them need to be disassembled and replaced to replace the seal.

7. Sudden leakage during normal operation. A few of the sudden leakage of the centrifugal pump during operation is due to normal wear or the service life has been reached, but most of them are caused by large changes in working conditions or improper operation and maintenance.

8. Evacuation, cavitation or pressure holding for a long time, resulting in damage to the seal;

9. The actual output of the pump is relatively small, and a large amount of medium circulates in the pump, and the heat accumulates, causing the medium to vaporize and resulting in seal failure;

10. The return flow rate is too large, causing the bottom of the container (tower, kettle, tank, pool) on the side of the suction pipe to have sediment floating and damage the seal;

11. For a longer period of outage, there is no manual cranking when restarting, and the friction pair will tear the sealing surface due to adhesion;

12. Corrosive, polymeric and gelling substances in the medium increase;

13. Rapid changes in ambient temperature;

14. Frequent changes or adjustments in working conditions;

15. Sudden power failure or shutdown due to failure, etc. The centrifugal pump leaks suddenly during normal operation. If it cannot be found in time, it will often lead to major accidents or losses. It must be paid attention to and effective measures should be taken.

The above is the key to the failure of the pump mechanical seal, so in use, we need to pay extra attention to better maintain the efficiency of the equipment.