Cavitation occurs when the pressure in a liquid locally drops below the vapour pressure of the liquid. This causes the liquid to evaporate and form small vapour bubbles that collapse violently as they move into areas of higher pressure. These collapses trigger powerful microscopic shockwaves - like small explosions - that wear down materials and components.

It can be compared to thousands of tiny air bubbles suddenly imploding and smashing against a metal surface at high speed. In industrial systems such as pumps, valves and pipelines, cavitation can quickly lead to serious damage if not detected and dealt with in time.

How does cavitation occur?

Cavitation typically occurs in areas with low pressure and high flow rate. It happens for example:

• at pump inlet where the fluid accelerates and the pressure drops
• in valves with high pressure drop where fluid movement creates turbulence
• in tank inlets with inappropriate design that creates localised pressure variations

Other factors such as high fluid temperature and low net positive suction head height (NPSH) also increase the risk. The higher the temperature, the lower the vapour pressure of the liquid - and the easier it can form bubbles.

What are the consequences of cavitation?

Cavitation is not just an annoyance - it's a real operational risk that can lead to:

• Erosion of impellers and valve seats
• Noise and heavy vibrations
• Lower efficiency and higher energy consumption
• Increased risk of breakdowns and downtime
• Need for more frequent maintenance and replacement

The small pressure shocks from collapsing bubbles wear directly on the metal - and the effects build up quickly. Even short-term cavitation can cause permanent damage over time, compromising both safety and process stability.

Where does cavitation typically occur?

Cavitation is especially seen in:

• Pumps where the pressure drops too much at the inlet
• Valves where high pressure drop or inappropriate flow control causes bubbling
• Heat exchangers and pipework with narrow passages or sudden changes in flow

It doesn't necessarily occur in the same place every time. It all depends on the fluid's properties, temperature, pressure, geometry and speed. Therefore, it's important to understand both the flow and the process environment to identify the risk.

How do you avoid cavitation?

Prevention starts with understanding. To avoid cavitation, you need to:

• Ensure correct sizing of pumps, pipes and valves
• Maintain sufficient inlet pressure
• Avoid excessively long or narrow suction lines
• Reduce turbulence and unnecessary pressure drops
• Take into account the vapour pressure and temperature of the liquid
• Use robust materials that can better withstand cavitation if it cannot be completely avoided

It's all about designing the system so that the fluid moves stably and without pressure drops below critical levels.

How Alflow helps you prevent cavitation

At Alflow, we help you choose the right components - and understand how your entire system works together. Our advice is based on years of experience with process equipment in pharma, food, chemical and biotech.

We offer:

• Technical advice on pumps, valves and flow
• Sizing help and product selection
• Documentation and data to ensure correct selection
• Solutions that reduce the risk of cavitation - and minimise wear

We know that even small pressure differences can have big consequences. That's why we help you design and choose right from the start.

Read more about:
www.alflow.dk/produkter/pumper/
www.alflow.dk/produkter/ventiler/
www.alflow.dk/kvalitet-og-dokumentation/
www.alflow.dk/kontakt/
www.alflow.dk/ordbog/

FAQ

What does cavitation mean?
Cavitation is when vapour bubbles form and collapse in a liquid because the pressure drops below the vapour pressure of the liquid. This creates small shock waves that wear down materials and can damage equipment.

How does cavitation occur?
Cavitation occurs at low pressure and high flow, typically in pumps and valves. When the liquid evaporates and then quickly liquefies again, the bubbles collapse and trigger pressure surges.

What does cavitation mean?
Cavitation is the English word for cavitation. It describes the same phenomenon of vapour bubbles forming and collapsing in a liquid due to low pressure.

Why does a pump cavitate?
A pump cavitates if the inlet pressure is too low. This can be caused by poor pipework, high flow, too long suction lines or the wrong type of pump. The result is vapour bubbles and pressure surges inside the pump.

Want to avoid cavitation in your systems?
Contact us - we'll help you get a handle on flow, pressure and components.
www.alflow.dk/kontakt/