Glossary · Pneumatics and hydraulics
Cavitation
Also known as: Pump cavitation
German: Kavitation
In hydraulics and fluid handling, cavitation is the formation and sudden collapse of vapor bubbles in a liquid where the local pressure falls below the vapor pressure, typically at pump inlets, valves and restrictions, causing noise, vibration and erosion of surfaces.
- Fluid power
In one sentence
Cavitation is the forming and collapse of vapor bubbles where liquid pressure drops too low, causing noise, vibration and erosion.
Example
A hydraulic pump with a clogged suction strainer starts to cavitate, making a rattling noise and losing delivery.
How it applies
- Engineering: Suction lines are sized for low flow velocity and pressure loss; pumps are placed below or close to the tank level, and fluid temperature and viscosity are considered.
- Operation: Symptoms are a crackling or rattling noise, vibration, pressure fluctuations and reduced performance.
- Maintenance: Clogged suction filters, low fluid level, wrong viscosity (cold start) and air leaks in the suction line are common causes. Cavitation damage shows as pitting on pump parts and valve seats.
- Documentation: Put cavitation in the troubleshooting table with symptoms, causes and remedies. State fluid level checks and suction filter intervals in the maintenance schedule, and warn against running the pump with low fluid.
Cavitation vs. aeration
Cavitation creates vapor bubbles from the liquid itself because pressure is too low. Aeration means air entering the fluid, for example through a leaking suction line or return line above the fluid level. Symptoms are similar, causes and remedies differ.