When the pump is in dynamic balance, it should be done together with the whole rotor components. The impeller has been replaced and the balance point has changed. It needs to be recalibrated. If it is a common single-stage pump, it will not be needed because the residual imbalance has little effect on the pump. If it is a high-speed pump or a multi-stage pump, it needs to be re-balanced. If it is a high-speed pump, it should be recalibrated. It is estimated that it should also be necessary to do so. For multi-stage pumps, the rotor components should be packed in small pieces and the position of each part should be marked after dynamic balancing. Then the whole pump can be assembled as a whole. In this way, the effect of dynamic balancing can be achieved.
Impeller dynamic balancing can be done by means of dynamic balancing machine. The general method is weight removal. Pump impeller is placed on the balancing machine and rotated at high speed. The opportunity of dynamic balancing calculates the amount of imbalance according to centrifugal force of partial gravity (including position of partial gravity) and displays on the screen of the balancing machine. Then, the place of partial gravity is removed. After several repetitions, the smaller the error, the better, so that the balance standard of the pump impeller can be reached.
Conditions for dynamic balance of pump rotor: high-speed pump needs dynamic balance detection, and low-speed general pump needs only static balance.
1) For the rotors of single-stage pump and two-stage pump, only static balance should be done whenever the working speed is less than 1800 rpm, whether D/b < 6 or D/b < 6. However, if dynamic balancing is required, D/b < 6 must be ensured, otherwise static balancing can only be done.
2) For the rotors of single-stage pump and two-stage pump, only static balance can be done if the working speed (> 1800 rpm) is D/b (> 6). However, the residual unbalance after balancing is equal to or less than 1/2 of the allowable unbalance. If dynamic balancing is required, it depends on whether the balancing of the two correction surfaces can be separated on the balancing machine. If this is not possible, only static balancing can be done.
3) For some open impellers and other rotors, if the support at both ends can not be achieved, only static balance can be done. Since the two ends can not be supported, it is necessary to carry out cantilever, so it is dangerous to do dynamic balancing on the balancing machine. Only one-sided (static) balancing can be carried out on the balancing frame.
If the rigid rotor can not satisfy the condition of disc rotor for static balance, two planes are needed to balance, i.e. dynamic balance. The rotor condition for static balance only is as follows (balance statics G0.4 is the highest accuracy, and in general the dynamic balance statics of the pump impeller is selected as G6.3 or G2.5):
1. For multi-stage pump and combined rotor (stage 3 or above), dynamic balance of combined rotor should be done regardless of working speed.
2. General single-stage centrifugal pump is not required.
3. Large single-stage pump (3000m3 circulating water pump) needs to be done.
4. Multi-stage pump is best done.
5. High-speed pump is best done once.
6. Impeller of regular pump manufacturer has been statically balanced.
Generally, the dynamic balance test is not necessary for single-stage pump when changing the impeller, but it should be ensured that the replaced impeller parts have done the dynamic balance test (if the user cuts the impeller diameter after the dynamic balance test, dynamic balance test needs to be done again). For multi-stage centrifugal pump, the impeller is replaced. Even if the impeller has been dynamic balance test, when replacing, the impeller is installed on the pump shaft, the whole rotor needs to be dynamic balance test again. And remember the position of each part, then remove the dynamic balance test impeller and reinstall the pump. Please contact our technician or customer service for the specific dynamic balancing machine you need.
Impeller dynamic balancing can be done by means of dynamic balancing machine. The general method is weight removal. Pump impeller is placed on the balancing machine and rotated at high speed. The opportunity of dynamic balancing calculates the amount of imbalance according to centrifugal force of partial gravity (including position of partial gravity) and displays on the screen of the balancing machine. Then, the place of partial gravity is removed. After several repetitions, the smaller the error, the better, so that the balance standard of the pump impeller can be reached.
Conditions for dynamic balance of pump rotor: high-speed pump needs dynamic balance detection, and low-speed general pump needs only static balance.
1) For the rotors of single-stage pump and two-stage pump, only static balance should be done whenever the working speed is less than 1800 rpm, whether D/b < 6 or D/b < 6. However, if dynamic balancing is required, D/b < 6 must be ensured, otherwise static balancing can only be done.
2) For the rotors of single-stage pump and two-stage pump, only static balance can be done if the working speed (> 1800 rpm) is D/b (> 6). However, the residual unbalance after balancing is equal to or less than 1/2 of the allowable unbalance. If dynamic balancing is required, it depends on whether the balancing of the two correction surfaces can be separated on the balancing machine. If this is not possible, only static balancing can be done.
3) For some open impellers and other rotors, if the support at both ends can not be achieved, only static balance can be done. Since the two ends can not be supported, it is necessary to carry out cantilever, so it is dangerous to do dynamic balancing on the balancing machine. Only one-sided (static) balancing can be carried out on the balancing frame.
If the rigid rotor can not satisfy the condition of disc rotor for static balance, two planes are needed to balance, i.e. dynamic balance. The rotor condition for static balance only is as follows (balance statics G0.4 is the highest accuracy, and in general the dynamic balance statics of the pump impeller is selected as G6.3 or G2.5):
1. For multi-stage pump and combined rotor (stage 3 or above), dynamic balance of combined rotor should be done regardless of working speed.
2. General single-stage centrifugal pump is not required.
3. Large single-stage pump (3000m3 circulating water pump) needs to be done.
4. Multi-stage pump is best done.
5. High-speed pump is best done once.
6. Impeller of regular pump manufacturer has been statically balanced.
Generally, the dynamic balance test is not necessary for single-stage pump when changing the impeller, but it should be ensured that the replaced impeller parts have done the dynamic balance test (if the user cuts the impeller diameter after the dynamic balance test, dynamic balance test needs to be done again). For multi-stage centrifugal pump, the impeller is replaced. Even if the impeller has been dynamic balance test, when replacing, the impeller is installed on the pump shaft, the whole rotor needs to be dynamic balance test again. And remember the position of each part, then remove the dynamic balance test impeller and reinstall the pump. Please contact our technician or customer service for the specific dynamic balancing machine you need.
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