CAVITATION

Cavitation is a hydraulic condition which can exist in any type of pump
It is primarily a situation in which the pump is discharging less liquid than its rated
capacity due to reduction or lack of supply to the pump
Common causes are
a) excessive suction lift
b)Net positive suction head avaialble is insufficient
c)selected operating speed is too high

Pitting,vibration and noises are common troubles stemming from cavitation

Severe cavitation will cause excessive noise and mild cavitation will give a small reduction
in pumping efficiency and moderate wear of the pumps parts

What you can do :-

a) slow down the pump
b) reduce suction lift
c) increase positive head pressure (reduce the suction head losses )
d) use bigger pump if you are not able to accept the
reduction of flow

Before going for the bigger pump . what is the right pump .........calculate
the NPSH avaialable ( NPSH A) , and the NPSHA must be higher than
NPSH required by the pump

Look up earlier postings on NPSH A