What are the hazards of an unbalanced pump impeller? How to dynamically balance a pump impeller

What will happen if the pump impeller is unbalanced?

Unstable impeller dynamic balance will cause the fan to vibrate excessively. If the vibration value is too large, the entire fan will make a loud noise, causing it to be unable to work normally. In severe cases, the fan will not be able to operate normally or even be damaged, causing certain economic losses. At this time, the machine needs to be shut down, which will seriously affect the production progress.

How to dynamically balance the pump impeller?

When the pump is dynamically balanced, the entire rotor part should be completed together with the pump impeller. If the impeller is replaced, the balance point will also change and needs to be recalibrated. If it is an ordinary single-stage pump, then it is not necessary, because the residual unbalance has little effect on the pump. If it is a high-speed pump or a multi-stage pump, it needs to be rebalanced. For multi-stage pumps, the rotor parts should be dynamically balanced, the positions of each part should be marked, and then the entire pump should be assembled as a whole to achieve the dynamic balancing effect.

If the rigid rotor cannot meet the conditions of the disc rotor for static balancing, it needs to be balanced on two planes, that is, dynamic balancing. The conditions for rotors that only require static balancing are as follows: balance static G0.4 is the highest precision, and the dynamic balancing static of the pump impeller is generally selected to be G6.3 or G2.5.

1. For the rotors of single-stage pumps and two-stage pumps, dynamic balancing should be performed when the working speed is ≥1800 rpm and D/b<6.

2. For multi-stage pumps and combined rotors (3 stages or more), dynamic balancing of the combined rotor should be performed regardless of the working speed.

3. General single-stage centrifugal pumps do not need to be balanced.

4. Large single-stage pumps (3000 m3 circulating water pumps) need to be balanced.

5. It is best to do it for multi-stage pumps.

6. It is best to do it for high-speed pumps.

7. The impellers of regular pump manufacturers have been statically balanced before leaving the factory.