How to determine the specific cause of the damage to a canned motor pump

If the canned motor pump remains in operation for a long time, problems may occur during the running process, making it unable to be used normally and possibly reducing the service life of the machine. So how can we determine which parts of the equipment are damaged?

I. Determine by analyzing the vibration and noise of the bearing:

(1) If the canned motor pump has abnormal vibration, it mainly comes from the two bearings of the motor part, indicating that the bearings are worn and need to be inspected.

(2) If the equipment experiences problems such as vibration, noise, TRG meter indication in the red zone, or low pump outlet pressure. It can be explained that when the pump body rotates in reverse, the phase sequence of the power line needs to be adjusted.

(3) If the inspected pump body is vibrating and the vibration source comes from the pump body, then the pump pressure test is normal when the outlet valve is closed. However, when the valve is opened, the pressure gauge indication suddenly drops, which indicates that the cavitation state of the canned motor pump needs to be improved and the inlet liquid level is high.

Ii. Analysis and judgment based on the indication of the bearing detector:

(1) If the gauge shows a yellow or red zone and all other conditions are normal, the bearings of the canned motor pump are worn and need to be replaced.

(2) If the gauge after the water pump shows no response but the normal indicators such as outlet pressure and current are damaged, a new gauge needs to be replaced.

Iii. Analyze and judge by disassembling the wear conditions of the components of the canned motor pump:

1) Check the wear of the pump body ring and the impeller ring. It indicates that the inner diameter of the bearing is excessively worn and the bearing needs to be replaced.

(2) If the front cover plate of the impeller and the pump body are found to be worn, it indicates that the front bearing surface is excessively worn and the bearing needs to be replaced.

(3) If the stator and rotor shielding sleeves are worn and the inner diameter of the bearings does not exceed the limit value, it indicates that when foreign objects enter the motor cavity, check whether the intake filter is damaged.

(4) Check that the end face of the rear bearing and the surface of the thrust plate are worn, while the front bearing and the thrust plate are not worn. This indicates that the axial thrust may flow backward too much and whether the outlet valve is opened too wide.

(5) The end face of the front bearing and the surface of the thrust plate are worn, while the rear bearing and the thrust plate are not worn, indicating that the canned motor pump is in a state of liquid shortage before the shaft push.

The above are some small methods for identifying the causes of damage to canned motor pumps. I hope they can be of help to you.