Multi-stage pump issues
Thread Content
Today, one of the multi-stage pumps in our factory is showing high current consumption and low flow rate during operation. Finally, we checked the motor and found it to be in good condition. We disassembled the pump and discovered that the impeller was worn; we used an impeller with one less stage, then reassembled the pump. Once it was in operation, the motor current was normal and the flow rate was also normal. Is this acceptable? Please advise.
LZ, please ask this question in the \"Conveyor Equipment Discussion Forum\". One stage of the impeller is missing – how do you address the issue of axial alignment in such a case?
In principle, it is possible, but it depends on whether the water supply pressure can meet the user’s needs. It is also necessary to continuously monitor the vibration levels of the pump shaft in all directions; if these levels are too high, the pump must be stopped for maintenance. What are the horizontal, axial, and vertical displacements of the pump during operation?
Theoretically, it is possible, but factors such as the balance of axial forces, axial positioning, and the adjustment of play must be taken into account. A trial run can be conducted, but with caution!
It’s mainly about observing vibration and temperature issues! Our multi-stage pump ran for a whole year with one stage missing
Your head or pressure should change, right! As long as it meets the process requirements, that’s sufficient
Ultimately, it’s because you chose a motor with too low a capacity. If one stage is missing from your impeller, the original axial force will definitely be different from the current value; the person who asked this question should pay attention to that. The poster can use the formula below to calculate whether the motor power chosen is too low. The pump shaft power N represents the actual power consumed by the centrifugal pump (including losses due to mechanical friction, flow losses, leakage, etc.), and it is calculated using the following formula: N = ρgQH/1000η, in kW. The power required for the motor should be set at 1.05–1.15 times N.
Running for a short period is okay, but to resolve the issue permanently, it’s better to choose another approach
With 8# QHDKD equipped with a smaller first-stage impeller, the pump’s head will definitely decrease. A multi-stage pump is simply a series connection of centrifugal pumps, with no change in flow rate. The main problem with your pump is still the positioning of the impeller; removing the impeller that causes friction does not solve the issue at its root. It depends on what is used to balance the axial force in your pump. Most likely, there’s a problem with its balancing mechanism.
1# guosulin1: It should be said that your multi-stage pump used to have high current consumption and low flow rate during operation. It was because the operating point of the original pump was incorrect – one impeller stage was missing. After installing the pump properly, the motor current returned to normal and the flow rate also became normal, which proves that there were no issues with the assembly; this approach is acceptable. It is a great method that serves multiple purposes at once. It saves electricity and extends the pump’s lifespan, which is certainly commendable. If we replace the pump now, we’ll need to go down one level directly.
What was said on the 9th floor is correct. It can meet your headlift requirement; one stage less is acceptable. The problem must lie in the axial dimension alignment! Check the dimensions of each spacing sleeve.