Types/Causes of Cavitation
SUCTION CAVITATION
Suction Cavitation – If a pump is operating under low pressure or high vacuum type conditions suction cavitation will occur. This condition will cause the pump to starve for liquid (too little NPSH, Clog or Reduced lines) causing vapor bubbles to form around the eye of the impeller. Once the liquid is subjected to pressures above the vapor pressure, these will implode against the face of the impeller.
- Pump is running too far right on the pump curve.
- Plugged or clogged filter, strainer or suction line.
- Pump is too far from the source, creating long suction line.
- Piping layout is designed poorly or too little NPSH.
- Too small of diameter on suction piping.
DISCHARGE CAVITATION
Discharge Cavitation –This occurs when the pump is being operated at the far left hand side of the pump curve. Having a high discharge pressure will cause the pump to circulate the fluid within the pump at a high velocity causing a vacuum around the housing wall leading to the development of vapor bubbles.
- Operating under too much head (too far left on the curve)
- Blockage in the piping, filters or strainers
- Piping layout designed poorly
