Cavitation Failure Analysis

Cavitation is caused by the presence of gas bubbles under high pressure being suddenly subjected to a low pressure.  This causes the bubbles to burst (implode) and release energy to the metal surface, which causes the fracture of small, minute pieces of metal from the base casting.

Possible
Cavitated Rotor

Possible Causes

Seal Water/Liquid Compressant

  • Incorrect seal water (liquid compressant) rates
  • Operation of liquid compressant above its vapor pressure
  • Liquid compressant saturated with minute gas bubbles under pressure

Blocked Discharges

  • Discharge port, pump outlet or drain blocked


Improper Clearances

  • Clearance wide on pumps operating at high vacuum levels


Improper Working Pressure

  • Working beyond maximum operating pressure (vacuum or compressor)

 

Possible solutions

Seal Water/Liquid Compressant

  • Ensure proper seal water/compressant rate
  • Lower vacuum
  • Change liquid compressant
  • Remove bubbles from liquid compressant


Blocked Discharges

  • Unblock all ports, outlets and drains


Improper Clearances

  • Ensure proper clearance is maintained


Improper Working Pressure

  • Lower operating pressure


A Nash Field Service Technician can help you diagnose a cavitation issue, and a Nash WebSentry can alert you about poor conditions before problems begin.  For more on these options, use the links below.

To see this maintenance tip in pdf format, click here