Requirements After Centrifugal Pump Stops Running

Dec 25, 2024

1, Requirements after centrifugal pump stops running

1. After the centrifugal pump stops running, the inlet valve of the pump should be closed, and the valves of the auxiliary system should be closed sequentially after the pump cools down.

2. The shutdown of high-temperature pumps should be carried out in accordance with the technical specifications of the equipment. After shutdown, the pump should be turned half a circle every 20-30 minutes until the temperature of the pump body drops to 50 ℃.

3. When the low-temperature pump is stopped, unless there are special requirements, the pump should be filled with liquid frequently; The suction valve and discharge valve should be kept in a normally open state; For low-temperature pumps using double end mechanical seals, the liquid level controller and the sealing liquid in the pump sealing chamber should maintain the grouting pressure of the pump.

4. Pumps that transport media that are prone to crystallization, solidification, and precipitation should be prevented from clogging after stopping the pump, and the pump and pipeline should be promptly flushed with clean water or other media.

5. Drain the accumulated liquid in the pump to prevent rust and frost cracking.

2, Analysis of the causes of cracking on the static ring end face of centrifugal pump mechanical seal

The common failure phenomenon of cracking on the static ring end face of centrifugal pump mechanical seals is also one of the most frequently failed sealing components. So, when these phenomena occur, what are the reasons?

1. The gap between the sealing surfaces during installation is too large, and the flushing solution cannot take away the heat generated by the friction pair in time; The flushing liquid leaked from the gap between the sealing surfaces, causing overheating and damage to the end faces.

2. The vaporization and expansion of liquid media cause the two end faces to separate due to the vaporization and expansion force. When the two sealing surfaces are tightly adhered, the lubricating film is damaged, resulting in overheating of the end face surface.

3. The lubricity of liquid media is poor, and coupled with operating pressure overload, the two sealing surfaces do not track and rotate synchronously. For example, a high-speed pump with a speed of 20445r/min and a center diameter of 175px on the sealing surface has a linear velocity of up to 75m/s after operation. When one of the sealing surfaces lags behind and cannot track rotation, the instantaneous high temperature causes damage to the sealing surface.

4. The sealing flushing liquid orifice plate or filter screen is blocked, causing insufficient water flow and resulting in the failure of the machine seal.