Common causes of pump vibration and mitigation measures

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1. Difficulties in manual shaft turning: bent pump shaft, worn bearings, misalignment of the unit, and the impeller touching the pump casing. Remedial measures: Straighten the pump shaft, adjust or replace the bearings, re-align the concentricity of the unit, and readjust the clearance. 2. Excessive shaft runout: Wear of the bearings and journal, or excessive clearance. Remedial measures: Repair the journal, adjust or replace the bearing. 3. Hydraulic imbalance: Imbalance of the impeller, or blockage or damage in certain vanes of the centrifugal pump. Remedial measures: Recalibrate the static and dynamic balance of the impeller, remove any blockages, and repair or replace the impeller. 4. Excessive shaft power of the axial flow pump: The water level in the inlet tank is too low, the immersion depth of the impeller is insufficient, debris gets entangled around the impeller, the degree of cavitation damage to the pump varies, and the impeller is damaged. Remedial measures: Raise the water level in the intake tank, lower the installation elevation of the pump, remove debris, install a trash rack, and repair or replace the impeller. 5. Foundation vibration: Poor foundation stiffness, loose base screws, or resonance. Remedial measures: Reinforce the foundation and tighten the anchor bolts. 6. The efficiency of the centrifugal pump unit drops sharply, or the efficiency of the axial flow pump unit decreases slightly, accompanied by cavitation noise. Mitigation measures: Change the pump speed to avoid the resonance range; determine the cause of cavitation and take measures to eliminate it.