What phenomenon causes pumps to make a pinging sound?

Cavitation is the phenomenon that causes pumps to make a pinging sound. This occurs when there are rapid changes in pressure within the pump, leading to the formation and collapse of vapor bubbles. When the pressure in the pump drops below the vapor pressure of the liquid, bubbles form. As these bubbles travel through the pump and reach areas of higher pressure, they collapse violently. This implosion can generate significant noise, often described as a pinging or rattling sound.

Cavitation not only produces this distinctive noise but can also cause damage to the pump's impellers and other components over time, affecting the pump's efficiency and longevity. Understanding cavitation is crucial for maintaining proper pump operation and mitigating potential damage, making it an important concept for water treatment operators.