If the normal operation of the pump, the pump head has sharp metal friction sound, pump power cut, remove the motor fan cover, manual barring, a certain angle resistance increased, with friction noise, the other angle resistance is normal, and no noise. There is hard friction in the pump body.
There are two common causes of friction:
- The foreign matter enters, possibly is in the running process, enters the pipe slag or the iron chip by the water pump suction inlet, also possibly is in the construction process, transfers the nut gasket class object by the water pump outlet. The treatment involves opening the water pump to remove the foreign matter.
- Pump impeller installation is not good, this situation more than the first pump or pump head after disassembly maintenance, it needs to open the pump head, re-installation positioning.
Either of the two types of failure, depending on the wear and tear to see whether they need to replace parts.
If the normal operation of the pump, the pump head has a crackling sound of popping beans, can make the pump inlet valve fully open state, try to adjust the pump outlet valve, the valve is open, the sound becomes louder, the valve is closed, then the sound becomes smaller, close to a certain angle or after all closed, abnormal noise disappear, you can judge the pump cavitation.
MPSH can occur for a variety of reasons:
- The system design problem mostly appears in the first start pump debugging, mainly with the entrance water temperature, the entrance pressure two factors are related, reduces the water temperature or raises the pump entrance pressure to be possible to solve this abnormal, or replace the pump with low cavitation allowance can also be solved.
- The filter at the inlet of the water pump is blocked, usually, for long-term normal operation, the valve of the water pump is not adjusted, suddenly found this abnormality, should be the system for long-term operation, the filter at the inlet of the water pump accumulates impurities, leading to blockage, this exception can be resolved by opening and cleaning the filter.
III. If the pump operates at the designed operating point, the cavitation margin can be satisfied, and when the operating point moves to the right, the cavitation margin rises, the system can not be satisfied and cavitation will occur, all kinds of instruments can be used to determine the pump operating point, close the pump outlet valve, restore to the design operating point
- Motor Noise
Motor running noise is usually the airflow noise of Motor Cooling Fan, which is much larger than the friction noise of motor rotor bearing.
But abnormal noise can also occur in the motor parts:
- Friction may occur between the fan and the fan cover. If the noise disappears after the fan cover is removed, the abnormal is judged. The problem can be solved by checking and adjusting the fan blade or fan cover.
- Motor Rotor bearing failure, if the removal of the fan cover, separate to the motor barring, full-angle resistance abnormal, can be judged as bearing failure. There are more than two possibilities, one is caused by water-bearing rust, the other is due to motor heat abnormal, bearing grease, need to replace the motor bearing to solve this abnormal sound.
- Noise From Coupling Operation
The pump with elastic coupling, if the coupling parts issued a periodic abnormal sound during operation, and accompanied by visible rubber powder off, can be judged as coupling noise, mostly because of poor alignment between the pump shaft and motor shaft, need to stop the machine after re-alignment.