How to predict pump failure

During the operation of the pump, pump failures can be predicted by observing or monitoring the pump’s flow, sound, vibration, temperature, current, electrical protection element tripping, and controller alarms. Companies should predict faults through various methods based on their own operating conditions: flow, sound, vibration, and temperature are the basic fault prediction methods; qualified companies can further predict faults based on current, electrical protection element tripping, and controller warning for prediction.

 

Pump failure prediction and handling should adhere to the principle of pre-judgment first, then on-site confirmation, in the end, processing.

1. Flow decreases significantly


If the pump flow rate drops significantly (by more than 20% of the normal value), you can check it one by one as follows and take corresponding measures.
a)The valve of the pump outlet pipe is not open or blocked: you can open the valve or clear the pipe.
b)The suction head of the pump exceeds the standard: lower the installation height of the pump or replace the pump with a larger suction head.
c)The suction pipe and bottom valve are leaking: repair or replace the suction pipe and bottom valve.
d)Insufficient submersion depth of the bottom valve: The submersion depth of the bottom valve should be greater than 1.5 times the diameter of the water inlet pipe. If it is insufficient, the water entry depth should be increased.
e) If The impeller is clogged or the sealing ring is worn: clean the clogged impeller or replace the worn impeller sealing ring.
f)Parts corroded: Replace the severely corroded parts.
g)Impeller steering error: Adjust motor wiring.
h)Motor sweep: replace bearings or motor.

2. No flow


a)Check the power supply. If the power supply is not connected, reconnect it.
b)Check whether the relay and contactor can operate effectively. If not, replace the damaged relay or contactor.

3. Predict by sound


If there is noise or abnormal sound during pump operation, the pump should be moved to the maintenance area and checked one by one as follows, and corresponding measures should be taken.
a)The motor bearing is damaged or stuck: Replace the motor bearing.
b) If The pump bearing is damaged or the impeller is stuck: replace the bearing or clean the impeller foreign matter.
c)The main shaft of the water pump is bent or is not concentric or parallel with the main shaft of the motor, etc.: Correct the bent main shaft of the water pump or adjust the relative position of the water pump and the motor.
d)The installation is not correct or the water pump is installed too high: Stabilize the water pump or lower the installation height of the water pump.
e)The liquid level in the water inlet well is too low: adjust the water inlet liquid level.
f)The suction inlet is blocked: clear the block matter in the suction inlet of the pump body.

4. Predict by vibration


The causes of abnormal pump body vibration failures are mainly divided into mechanical reasons and hydraulic reasons.
Mechanical reasons:
a)The pump impeller or bearing is blocked by foreign matter: clean the foreign matter.
b)Uneven mass distribution in the pump impeller or motor rotor: the impeller or motor should be replaced.
c)The pump main shaft and motor shaft are deviated: adjust the pump main shaft and motor shaft to be concentric.
d)The bolt spacing of the coupling is unqualified: adjust the gap between the couplings.
e)The main shaft of the pump is bent, and the rotating part comes into contact with the bushing and bearing bush, causing the pump shaft to deflect: replace the abnormal parts.
Hydraulic reasons:
a)Cavitation Causes Vibration, Replaceable High Suction Lift Pump.
b)The water flow hits the diaphragm tongue and the leading edge of the guide vane to cause vibration: adjust the distance between the impeller outlet and the pump volute diaphragm tongue or the leading edge of the guide vane.
c) If The liquid level in the water well is too low or the pump suction inlet is blocked: adjust the water inlet level or clear the foreign matter in the pump suction inlet.
d)Surge phenomenon: handle according to the pump instructions.

5. Predict by temperature


If the pump temperature is too high, you can check it one by one as follows and take corresponding measures.
a) Bearing wear or jamming: add lubricant or replace the bearing.
b) Bearing or motor overload: reduce the operating power or replace the water pump with a higher power.
c) Lack of conveying medium: Make sure the valves at the front and rear of the pump body are open to ensure sufficient height of the conveying medium.

6. Predict by current


When the current is abnormal, the pump should be moved to the maintenance area and checked one by one as follows, and corresponding measures should be taken.
a) Abnormal working conditions: Verify on-site working conditions, and replace or adjust facilities that do not meet working conditions.
b) Bearing abnormality: Check, repair, or replace the bearing.
c) The speed exceeds the rated speed: check the circuit voltage and reduce the pump speed.
d) If The coupling is not concentric or the pump shaft is bent: correct or replace the pump shaft.
e) There is debris blocking: clean the debris.
f) The motor ball bearing is damaged: Replace the motor ball bearing.
g) Improper pump lift: Replace the pump with a suitable lift.