Diagnosing Pump Cavitation - The Informative Brief

Cavitation normally creates random, higher frequency vibration or “noise”.

It is often observed as a “hump” in the vibration spectrum raising the floor from about 15X to 35X.

Cavitation normally indicates insufficient suction pressure or starvation - i.e., low inlet pressure.

The liquid tends to vaporize while coming off the impeller creating vacuum bubbles that implode. The waveform can often sound like gravel in the pump.

Diagnosing Cavitation :

• High frequency, random vibration. 
• Sounds like the pump is pumping gravel.
• cavitation causes excessive wear on the impeller and other internal components.
• May come and go from one collection to the next as the load varies.

Recommended Actions:

• Assess operational parameters (flow rates and pressure).Actual flow and pressure should be compared to the pump curve and design point of the pump. Insufficient flows and/or pressures lead to cavitation.
• Inspection of the internal components (impeller vanes) for excessive wear.