What are the reasons why a segmented multistage centrifugal pump cannot pump water?

The segmented multistage centrifugal pump is a common and widely used general-purpose mechanical equipment. However, sometimes the pump may suddenly fail to pump water during use. What are the reasons for the multistage centrifugal pump failing to pump water? And how should it be handled?

1. The air inside the multistage pump has not been fully evacuated, or the vacuum is insufficient

Judgment method:

a. Open the exhaust valve or exhaust bolt to check if any gas is discharged;

b. Check the vacuum gauge to see if the reading is below -0.2mpa;

Handling method:

a. Exhaust all air from the pump, check whether the water diversion is working, whether the pipeline is leaking, and whether the packing leakage is excessive;

b. Check whether the pipeline is leaking, whether the packing is leaking excessively, whether the vacuum pump is functioning properly, and whether the water pressure of the jet air pump is normal;

2. The inlet pipe is blocked, and the foot valve is blocked

Judgment method:

a. The vacuum degree indicated on the vacuum gauge reaches below -0.2;

b. When opening the exhaust valve or exhaust hole, no liquid flows out;

Treatment methods: inspection, cleaning, pipeline filter, filter screen, foot valve, gate valve.

3. The motor rotation direction is incorrect, and the motor is not connected to the pump

Judgment method for segmented multistage centrifugal pumps:

a. Jog the motor to check if its rotation direction is consistent with that of the water pump;

b. Check whether the coupling pin is installed;

Processing method:

a. Change the rotation direction of the motor;

b. Connect the coupling pin.

4. Air leakage due to packing or significant leakage from the mechanical seal

Judgment method: Check whether the packing is dry, whether the shaft sleeve is worn, and whether the mechanical seal is worn;

Handling method:

a. Replace the packing or shaft sleeve, and apply butter on the packing;

b. Replace the mechanical seal of the segmented multistage centrifugal pump (minor leakage will not affect water filling).