Cavitation damage typically affects which pump components?

• A. Electrical windings
• B. Bearings only
• C. Impeller and pump housing
• D. Control panel

Answer: (C)

Cavitation damage is the erosion of metal surfaces caused by collapsing vapor bubbles in the flowing liquid. These bubbles collapse with enough energy to create tiny jets and shock waves that strike nearby solid surfaces. The parts that bear the brunt of this exposure are the ones directly in contact with the moving flow: the impeller blades and the pump housing. Erosion shows up as pitting, thinning, and roughening of the blade surfaces and the inner walls of the housing, which also reduces efficiency and can lead to imbalance or failure.

Electrical windings and control panels aren’t exposed to the erosive microjets that cavitation produces, so cavitation damage isn’t seen there. Bearings can suffer from the resulting vibration if cavitation is severe, but that’s a secondary consequence; the primary, characteristic damage location is the impeller and the pump housing.