Causes and solutions for leakage of mechanical seal of submersible pumps

Mechanical seal is also called end face seal, usually called "mechanical seal". It is a key component of submersible pump waterproofing. The phenomenon of mechanical seal leakage in the use of submersible pumps is more common in submersible pump failures. At the same time, mechanical seals The operation of the seal directly affects the normal operation of the pump. In order to ensure the normal operation of the submersible pump and avoid accidents caused by the leakage of the mechanical seal during operation, the leakage of the mechanical seal is summarized and analyzed as follows.Get more news about Submersible Pump Seals,you can vist our website!

1. The axial movement of the submersible pump rotor is too large, and the interference between the auxiliary seal and the shaft is large, and the moving ring cannot move flexibly on the shaft. After the pump is turned over and the static ring is worn out, the pump cannot be compensated for displacement.

Corresponding solution: When we assemble the submersible pump mechanical seal, the axial movement of the submersible pump shaft should be less than 0.1mm, and the interference between the auxiliary seal and the shaft should be moderate. While ensuring the radial seal, the moving ring should be assembled After that, it is guaranteed to be able to move flexibly on the shaft (press the moving ring to the spring to be able to bounce back freely).

2. The insufficient amount of lubricating oil on the mechanical sealing surface of the submersible pump will also cause dry friction or roughening of the sealing end surface. The corresponding solution: the height of the lubricating oil surface in the oil chamber of the submersible pump should be kept higher than the mechanical sealing surface of the dynamic and static rings.

3. Periodic vibration of the rotor of the submersible pump. It is because the stator and the upper and lower end caps are misaligned or the impeller and the main shaft are unbalanced, cavitation or bearing damage (wear), this situation will shorten the seal life and cause leakage. Corresponding solutions: the above problems can be corrected according to the maintenance standards.

B. The phenomenon of shaft grinding of the submersible pump caused by the leakage of the submersible pump seal

The mechanical seal failure of small pumps below 715kW often produces grinding shafts. The grinding shaft positions of submersible pumps are mainly as follows: the auxiliary sealing ring of the moving ring, the position of the static ring, and a few springs have the phenomenon of shaft grinding.

The main causes of shaft grinding:

1. BIA type double end face mechanical seal, the back pressure state is a bad working state, particles and impurities in the medium can easily enter the sealing surface and cause the seal to fail.

2. The main part of the submersible pump grinding shaft is a rubber bellows, and because the upper sealing surface is in a poor lubrication state, the friction torque between the moving and static rings is greater than the transmission torque between the rubber bellows and the shaft, and relative rotation occurs.

3. The dynamic and static ring auxiliary seal is corroded by the weak acid and weak alkali in the sewage, and the rubber parts have no elasticity. Some have rotted and lost their proper function, resulting in the phenomenon of shaft grinding.