Causes of centrifugal pump seal damage are as follows, with specific details and treatment methods for each item

1. Poor water quality of centrifugal pump with particles. Due to poor water quality containing small particles and high hydrochloride content in the medium, abrasive wear occurs on the mechanical seal faces of the centrifugal pump, or grooves and annular grooves are formed on the surfaces due to scratches. Treatment method: improve water pressure or medium conditions, and replace the mechanical seal.

2. Cavitation. Cavitation mainly occurs in hot water centrifugal pumps. As the medium is hot water, excessively high water temperature generates steam, and gas in the pipeline accumulates at the upper part of the pump chamber. This part of gas cannot be discharged, resulting in water shortage operation, dry friction failure of the mechanical seal and cavitation damage. Treatment method: replace the mechanical seal.

3. Dry running damage caused by water shortage. This phenomenon is mostly seen in installations with negative pressure at the inlet, air in the water inlet pipe and air in the pump chamber. After the pump is started, high-speed friction of the mechanical seal produces high temperature without cooling. Inspection shows that the spring tension of the mechanical seal is normal, but the friction surfaces are charred and blackened, and the rubber is hardened and cracked. Treatment method: exhaust all air in the pipeline and pump chamber, and replace the mechanical seal.

4. Excessively tight installation. Observation of the rotating and stationary ring faces of the mechanical seal shows severe charring, blackened surfaces with deep marks, and hardened and inelastic sealing rubber. This phenomenon is caused by excessively tight installation. Treatment method: adjust the installation height. After installing the impeller, stir the spring with a screwdriver. The spring shall have strong tension and return to its original position after being released, with a moving distance of 2-4mm.

5. Water leakage at the mechanical seal. Treatment method: fill the leakage gaps with high-density materials, or replace the mechanical seal.

6. Excessively loose installation. Observation of the rotating and stationary ring faces of the mechanical seal shows a thin layer of water scale that can be wiped off, with basically no surface wear. This is caused by loss of spring elasticity, poor assembly or axial movement of the motor shaft. Treatment method: replace the spring and motor shaft, and reassemble.