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Causes and maintenance of insufficient water supply and insufficient water in centrifugal pump
- Jul 13, 2018 -

Centrifugal pump failure reason:

The bottom valve of the pump is not tightly closed or the water pump suction pipe is leaking seriously.

Maintenance method:

First, the approximate part of the failure is judged by eye and ear. Then, pull the pump suction pipe out of the water for inspection. If the bottom valve of the water pump is not tightly closed, the bottom valve should be disassembled for repair or replacement; if the water pump suction pipe leaks, the specific leaking part should be detected by the light method, and the air leakage at the pipe wall should be repaired. Strict or replacement method; for air leakage at the interface of the suction pipe, the method should be repaired by tightening the flange connection bolt with a wrench or replacing the contact pad and then tightening.

Insufficient water output from the centrifugal pump:

cause of issue:

1 The actual lift of the pump exceeds the rated head.

2 The speed of the pump unit is not matched or the speed is low due to the belt slippage.

3 pump suction is too high.

4 The bottom valve of the water pump is not open enough or the check valve is blocked.

5 The pump suction and outlet pipes are leaking seriously.

6 The pump pipe and impeller are partially blocked or the impeller is defective.

Maintenance method:

1 Reinstall the water pump and reduce the installation height of the water pump properly so that the actual lift is less than the rated lift of the pump. If the fault cannot be eliminated, the centrifugal pump should be re-selected according to the actual situation on site.

2 First, check whether the power pump of the pump set matches the pump (main technical parameters such as power, speed, etc.). If it does not match, the power machine should be properly configured according to the technical parameters marked on the pump nameplate (or take the pulley with different diameter of the replacement pump). ) to meet the power and speed requirements of the pump. Secondly, check the power transmission of the pump set. If the pump speed is low due to the slip of the drive belt, stop the dirt on the pump drive belt and re-lap and adjust the tension of the belt as required.

a. Transmission belt installation requirements

The distance between the axis of the pump and the axis of the power machine (diesel engine) is preferably 1.5 to 3.0 meters. At the same time, the axis of the two axes should be parallel and can be inspected by the wire drawing method. If the cable is equidistant from the sides of the two pulleys, it means that the two axes are parallel; if they are not parallel, they should be corrected. Otherwise, the belt is easy to fall off during work, which affects both work and safety.

b. Driving belt installation method

When installing the belt, the tight side of the belt should be placed below to increase the wrap angle of the belt to achieve the purpose of improving transmission efficiency and prolonging service life.

3Reinstall the pump after parking and reduce the pump installation height.

4 After parking, first check the working state of the bottom valve of the pump. If the bottom valve is not open enough or there is an obstacle to opening, open the large bottom valve or replace the new bottom valve. Next, check the working condition of the check valve. If blockage or damage occurs, remove the blockage or replace the new check valve.

5 After parking, check the suction and outlet pipes of the pump by the light method. If there is air leakage at the pipe wall, take the method of repairing the blockage or replacing the new pipe; if it is leaking at the interface, use a wrench to tighten the flange. Connect the bolts or replace the contact pads before tightening.

6 After parking, first check the pipeline to find the blockage and remove the blockage. Then remove the water pump to check. If the impeller is wrapped by debris, the impeller should be removed and the winding debris should be removed. If the pump is cavitation due to cavitation, the impeller should be repaired or replaced.

Partial damage of the impeller can be repaired by welding, or a layer of epoxy resin mortar can be applied to the entire worn blade, which can receive better control effect. In addition, the repaired impeller should generally be subjected to a static balance test.


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