THE PHENOMENON OF CAVITATION
Cavitation in flow systems is a dynamic phenomenon dependant on the nature of the flow and the properties of the flowing liquid. It occurs when the pressure is reduced locally to vapour pressure.
Under these conditions vapourous cavities form and when transported into higher pressure areas, these cavities (bubbles) collapse with rapid condensation of the vapour. High energy concentrations and rapidly fluctuating pressures result and damage ensues.
In practical terms…….cavitation normally causes noise and severe pump wear.
If left, the pump will fail, shedding it’s debris into the system – causing a whole host of other problems.
The most common causes of cavitation are
+ blockage of suction strainer or filter
+ blockage in suction pipe (rag, redcap etc.)
+ partially closed suction valve
+ undersized suction piping
+ suction too long (too great a pressure drop)
+ position of tank relative to pump (make positive head?)