High vibration after replacing the impeller of the pump
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Everyone, there is a pump in my workshop whose flow rate needs to be increased. The design office provided parameters such as the medium, flow rate, and pressure. After conducting calculations, the original pump manufacturer replaced the impeller, while keeping the other components unchanged. After the pump was started up, the vibration level was around 6 when the frequency was set at 46; the vibration increased as the frequency rose or fell, reaching up to around 10. At a frequency of around 46, the motor current reached its rated value. The manufacturer attributed this to installation issues, but I think it’s due to a mismatch between the new impeller and the original pump. I would appreciate everyone’s opinions. Thank you
In the event of such a problem, the only solution is to seek assistance from the manufacturer. If there are installation issues, someone will come to the site for guidance. If anyone says there’s a problem, let them give on-site guidance; otherwise, no payment will be made. Oh, there’s a problem here: the pressure and flow rates should remain stable and within the specified ranges. Check whether it is related to process control – overload?
The rotor is dynamically balanced. The question is: with the pump cover and pump body remaining unchanged and only the impeller being replaced, does the wider outer diameter of the impeller require an increase in rotational speed?
What kind of pump? Single-crank cantilever, supported at both ends, or multi-stage? Perform dynamic balancing on the rotor and check the magnitude of the imbalance. Please provide information on the pressure conditions at the site, the viscosity of the medium, the temperature, the bearing clearance data, as well as details on the runout and bending of various parts of the pump shaft. Also, provide information on the coupling alignment, and let me know if the inlet filter has been checked
Only the impeller has been enlarged, from 310 to 318
Single stage, supported at both ends, ready for dynamic balancing; the inlet filter is not clogged
Is there friction between the impeller and the pump casing?
Increasing the impeller diameter and reducing the frequency are contradictory to each other. The impeller flow channel needs to be redesigned to change the blade parameters.
Perform dynamic balancing on the impeller alone, straighten the shaft, perform dynamic balancing on the rotor, check the bearing shells at both ends, and try it again.
This issue cannot be resolved on the spot; it’s better to have the manufacturer come over.
Please provide the flow head, pump model, and pump nameplate