What type of balancing machine is used for dynamic balancing test of water pump impeller
When performing dynamic balancing on a water pump, the entire rotor component should be done together. If the impeller is replaced and the balance point is also changed, it needs to be readjusted. If it is a regular single-stage pump, it is not necessary because its residual unbalance has little impact on the pump. If it is a high-speed pump or multi-stage pump, dynamic balancing needs to be done again. I am not familiar with high-speed pumps, so I estimate it should be done. For multi-stage pumps, it is necessary to assemble the rotor components into small pieces, perform dynamic balancing, mark the positions of each component, and then assemble the entire pump to achieve dynamic balancing.
The dynamic balancing of impellers can be achieved through a dynamic balancing machine. The general method is to use the weight removal method, which is to place the required water pump impeller on the balancing machine, rotate it at high speed, and the dynamic balancing machine will calculate the unbalance amount based on the centrifugal force of the heavy weight, including the position of the heavy weight, and display it on the screen of the balancing machine. Then, the heavy weight will be removed. After repeating several times, the smaller the error, the better, so as to achieve the balance standard of the water pump impeller.
The conditions for balancing the rotor of a water pump are as follows: high speed pumps require dynamic balance testing, while low speed pumps typically only require static balance testing.
1) For the rotors of single-stage pumps and two-stage pumps, when the working speed is less than 1800 revolutions per minute, regardless of whether D/b<6 or D/b ≥ 6, only static balance should be performed. But if dynamic balancing is required, it must be ensured that D/b<6, otherwise only static balancing can be done.
2) For the rotors of single-stage pumps and two-stage pumps, when the working speed is ≥ 1800 revolutions per minute, if D/b ≥ 6, only static balancing can be performed. But the remaining unbalance after balance should be equal to or less than half of the allowable unbalance. If dynamic balancing is required, it depends on whether the balancing of the two calibration surfaces can be separated on the balancing machine. If they cannot be separated, only static balancing can be performed.
3) For some open impellers and other rotors, if it is not possible to achieve support at both ends, only static balancing can be done. Because the two ends cannot support each other, it is necessary to use cantilever, which makes dynamic balancing on the balancing machine very dangerous. Only single-sided (static) balancing can be carried out on the balancing frame.
If a rigid rotor cannot meet the requirements of a disc-shaped rotor for static balancing, two planes are needed for balancing, namely dynamic balancing. The rotor conditions for only static balance are as follows (balance static degree G0.4 is the highest accuracy, and in general, the dynamic balance static degree of the pump impeller is selected as G6.3 or G2.5):
1. For multi-stage pumps and combination rotors (3 stages or above), dynamic balancing of the combination rotor should be performed regardless of the operating speed.
2. A typical single-stage centrifugal pump does not need to be used.
3. A large single-stage pump (3000m3 circulating water pump) needs to be made.
4. It's best to make a multi-stage pump.
5. It's best to make a high-speed pump.
6. The impeller of a regular pump manufacturer has been statically balanced before leaving the factory.
Usually, a single-stage pump does not need to undergo a dynamic balance test again when replacing the impeller, but it should be ensured that the replaced impeller parts have undergone a dynamic balance test (if the user cuts the impeller diameter after the dynamic balance test, a new dynamic balance test needs to be conducted). For multi-stage centrifugal pumps, even if the impeller has undergone a dynamic balance test, when replacing it, the impeller should be installed on the pump shaft, and the entire rotor needs to undergo a dynamic balance test again. Remember the position of each part, and then remove and press the position where the balance test impeller is located to reinstall the pump.
When performing dynamic balancing on a water pump, the entire rotor component should be done together. If the impeller is replaced and the balance point is also changed, it needs to be readjusted. If it is a regular single-stage pump, it is not necessary because its residual unbalance has little impact on the pump. If it is a high-speed pump or multi-stage pump, dynamic balancing needs to be done again. I am not familiar with high-speed pumps, so I estimate it should be done. For multi-stage pumps, it is necessary to assemble the rotor components into small pieces, perform dynamic balancing, mark the positions of each component, and then assemble the entire pump to achieve dynamic balancing.
The dynamic balancing of impellers can be achieved through a dynamic balancing machine. The general method is to use the weight removal method, which is to place the required water pump impeller on the balancing machine, rotate it at high speed, and the dynamic balancing machine will calculate the unbalance amount based on the centrifugal force of the heavy weight, including the position of the heavy weight, and display it on the screen of the balancing machine. Then, the heavy weight will be removed. After repeating several times, the smaller the error, the better, so as to achieve the balance standard of the water pump impeller.
The conditions for balancing the rotor of a water pump are as follows: high speed pumps require dynamic balance testing, while low speed pumps typically only require static balance testing.
1) For the rotors of single-stage pumps and two-stage pumps, when the working speed is less than 1800 revolutions per minute, regardless of whether D/b<6 or D/b ≥ 6, only static balance should be performed. But if dynamic balancing is required, it must be ensured that D/b<6, otherwise only static balancing can be done.
2) For the rotors of single-stage pumps and two-stage pumps, when the working speed is ≥ 1800 revolutions per minute, if D/b ≥ 6, only static balancing can be performed. But the remaining unbalance after balance should be equal to or less than half of the allowable unbalance. If dynamic balancing is required, it depends on whether the balancing of the two calibration surfaces can be separated on the balancing machine. If they cannot be separated, only static balancing can be performed.
3) For some open impellers and other rotors, if it is not possible to achieve support at both ends, only static balancing can be done. Because the two ends cannot support each other, it is necessary to use cantilever, which makes dynamic balancing on the balancing machine very dangerous. Only single-sided (static) balancing can be carried out on the balancing frame.
If a rigid rotor cannot meet the requirements of a disc-shaped rotor for static balancing, two planes are needed for balancing, namely dynamic balancing. The rotor conditions for only static balance are as follows (balance static degree G0.4 is the highest accuracy, and in general, the dynamic balance static degree of the pump impeller is selected as G6.3 or G2.5):
1. For multi-stage pumps and combination rotors (3 stages or above), dynamic balancing of the combination rotor should be performed regardless of the operating speed.
2. A typical single-stage centrifugal pump does not need to be used.
3. A large single-stage pump (3000m3 circulating water pump) needs to be made.
4. It's best to make a multi-stage pump.
5. It's best to make a high-speed pump.
6. The impeller of a regular pump manufacturer has been statically balanced before leaving the factory.
Usually, a single-stage pump does not need to undergo a dynamic balance test again when replacing the impeller, but it should be ensured that the replaced impeller parts have undergone a dynamic balance test (if the user cuts the impeller diameter after the dynamic balance test, a new dynamic balance test needs to be conducted). For multi-stage centrifugal pumps, even if the impeller has undergone a dynamic balance test, when replacing it, the impeller should be installed on the pump shaft, and the entire rotor needs to undergo a dynamic balance test again. Remember the position of each part, and then remove and press the position where the balance test impeller is located to reinstall the pump.
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