Cavitation in pumps occurs when air bubbles form and collapse inside the pump due to low pressure. When the bubbles collapse, they create shockwaves that can damage pumps. Cavitation happens when the available net positive suction head (NPSHa) is lower than the required NPSH (NPSHr), or when the suction pressure is below the fluid's vapor pressure. Signs of cavitation include noise, vibration, seal/bearing failure, impeller erosion, and decreased flow or pressure. To prevent cavitation, proper pump selection and installation, maintenance, and troubleshooting are important.

2. Cavitations in Pumps:
•Cavitation in pumps is the rapid
creation and subsequent collapse of
air bubbles in a fluid.
•Cavitation is the formation and
accumulation of bubbles around a
pump impeller (refer a video).
•When each of these tiny bubbles
collapses or bursts, it creates a high
energy shock wave inside the liquid
(Watch a video of bubbles implodes on
surface).

3. Cavitations in Pumps:
•Cavitations happens when:
NPSH Available is lower than NPSH
Required
i.e. NPSHa< NPSHr
Suction pressure is lesser than the
vapour pressure of fluid.
For e.g.: Degassing water under high
vacuum (watch video to understand)

4. Cavitations Reorganization:
Typical indications of cavitations:
•Noise
•Vibration
•Seal/bearing failure
•Impeller erosion
•Higher than usual power consumption
•Decreased Flow or Pressure
•UnexpectedVibrations

5. PREVENT PUMP CAVITATION:
1. PUMP SELECTION: When purchasing new pumps, consider
the pump design and always question whether it meets the
Net Positive Suction Head (NPSH) requirements.
2. ADDRESSING DISCHARGE CAVITATION: Discharge
cavitation occurs when pressure at the discharge end of
the pump is too high. High discharge pressure limits the
volume of fluid flowing out of the pump, causing high-
velocity fluid to recirculate between pump impeller and
housing, causing cavitation.

6. PREVENT PUMP CAVITATION:
3. ROUTINE PUMP MAINTENANCE:
•Check filters and strainers.
•Assess the entire pump system design
•Evaluate the curve.
•Monitor pressure sensing equipment.
•Look for cracks or collapsed piping/hoses that will disrupt
the system.

7. PREVENT PUMP CAVITATION:
4. PROPER INSTALLATION:
•Pump location
•Suction pipe length and diameter
•Suction lift, or the vertical distance from water source to pump
inlet
•Friction loss

8. 5.TROUBLESHOOTING CHECKLIST
•Is the pump installed too high above the fluid source?
•Is suction pipe diameter too small?
•Is the suction pipe too long?
•Are there too many fittings on the suction pipe?
•Is the pump running too fast?
•Is the suction line to the pump sloped properly?