Cavitation:
Proper design of the pump inlet supply is critical to the success of any pumping
system. The supply can be gravity, suction or pressure fed depending on the pump
selected. Improper supply to the pump will cause cavitation. Cavitation is the
formation and collapse of gaseous pockets
(cavities) in a liquid.
Cavitation occurs when a lack of liquid
to the inlet causes vaporization in the low pressure chamber of the pump.
When a vapor bubble is re-pressurized it
quickly collapses supersonically and the shock wave erodes the surface it is on.
Causes pitting
and erosion of metallic or ceramic components.
Cavitation will decrease pump
outlet flow and pressure as well because the pump doesn’t fully prime with
liquid. Instead, the pump is attempting to pump a combination of liquid
and vapor. Cavitation will cause shorter seal life, pitted valves, and
manifolds. The short seal life is caused by the lack of lubrication
(water is a lubricant in this scenario) increasing wear.