Condition Monitoring of Pumps
The major causes of pump failure are Cavitation, Piping Strain, Soft Foot, Impeller Rub & all other common causes like Bent Shaft, Misalignment, Transferred Vibration, Resonance, Bearing Failures, Unbalanced Impeller, etc.
Pump Condition Monitoring includes Condition Assessment of the pump then corrective actions if required followed by periodic condition monitoring data collection attempts and maintaining the trend of the data collected from the component of the pump.
CM of Pump = CAss + CA + CM visits – Trend Analysis
The condition of the Pump can be maintained by monitoring Pump Bearings, Motor Bearings, Impeller for Cavitation & Unbalance, Shaft for bent shaft condition/ Alignment, Foundation/Base Rail/Fastening. The CM techniques are Vibration Probing Study to check soft foot condition/ Foundation/Base Rail/ Fastening & Piping Strain, Vibration Measurements to check Bent Shaft, Alignment, Unbalance issues, Ultrasound Measurement to check Bearings – Faulty Bearing & Lubrication Issues, Impeller Cavitation Issues, etc.
In reality, the condition parts of the Pump is never seriously monitored. Just because more importance is always given to the motor driving the pump and pump is mostly ignored. In Pump Set, few of the issues are common in Pump & Motor both, like Foundation Rigidity, Base Rail Deformation, Misalignment, Coupling Issues, Soft Foot condition & even Piping Strain. But motor should be checked for Rotor Unbalance, Shaft Bent, Winding Overheating, Core Overheating etc. Same way pump should be separately checked for Impeller Cavitation, Impeller Unbalance, Impeller Rubbing, etc.
It is obvious that nobody will be interested in getting only PUMP condition monitoring done, as it is coupled with electric motor.
Hence, Condition Monitoring of Pump – Motor unit is always preferred. The CM of Pump-Motor unit is nothing but CM of Pump & CM of Motor. We have to consider it separately for Motor & Pump.
The Condition Monitoring of Pump – Motor Unit includes Condition Assessment of Pump as well as of Motor, followed by monitoring condition of components of pump – impeller, bearing, bearing housings & monitoring condition of a component of motor – bearings, windings, bearing housings, motor rotor, etc. and maintaining the trend of all this data. It also may include vibration probing study to learn about the condition of Foundation for Soft Foot, Base Rail for Deformation, Fastening and importantly for Piping Strain.
CM of Pump Unit = CAss of Pump (Once) + CAss of Motor (Once) + Probing Study (Once) + CM of Pump + CM of Motor – Trend Analysis
