What is Cavitation

Q: What is cavitation?

A: In a centrifugal pump, cavitation occurs when the absolute pressure at the eye of the impeller reaches the vapor pressure of the liquid. At this critical pressure (called the incipient point), tiny vapor pockets, or cavities, form at the eye of the impeller. As these vapor pockets move from the eye of the impeller (a low-pressure area) toward the pump discharge (a high-pressure area), they implode (or collapse). This implosion can cause considerable physical damage to the pump impeller and bearings.

You can identify cavitation by the distinct "popping" noise, similar to popcorn popping, that you can hear when it's happening. This "popping" is caused by the implosion of the vapor cavities. To hear cavitation in action, check out this GIW video, recorded in our own test lab.

Cavitation can be avoided by selecting a pump that operates well clear of the critical suction pressure, or Net Positive Suction Head (NPSH), required by the pump.

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