Question

what can be used to reduce noise in a pump ?

Answer 1

Use pipe bends of large radius to minimise the impacr of which which causes vibrations.

Use vibration isolators at the mounting to minimise vibrations.

Use pressure valves to reduce pressure when necessary.

Place a pumpset inside a room with sound insulation.

Limit the velocity of flow by increasing the pipe size.

Increase liquid level around suction area, reduce RPM of motor, Reduce temperature...this all will fix the problem of cavitation which causes noise in the pump.