Pump Cavitation: What to do if you suspect your pump has a cavity

Is your centrifugal pump becoming increasingly noisy? If yes, there’s a good chance that pump cavitation is the cause. While we’ve explained at length about what pump cavitation is, what causes it, and how to prevent it, we will explain in this article what to do if you expect your pump has a cavity.

As experts in pump maintenance, repairs, and testing, our pump division understands the importance of identifying and addressing pump cavitation as early as possible.

To ensure the proper functioning of your pump, it is crucial to have a reliable maintenance process in place.

Early identification of warning signs can prevent significant damage from occurring, and Cape Armature Winders (CAW) are the experts in pump maintenance, repairs, and testing in the Western Cape.

Suspect pump cavitation? Here are the signs to look out for

• Noise. First and foremost, your pump is going to start making an awful racket. This is as the bubbles of vapour implode within the pump. It sounds like marbles or stones are rattling around inside the pump or pipework.
• Decreased flow or pressure. Discharge pressure is reduced, and – in positive displacement pumps – cavitation results in a loss in flow rather than head or pressure. This is because the bubbles displace fluid from the pumping chamber, thus lowering capacity. 
• Unexpected vibrations. Vibrations are one of the symptoms most common with pump cavitation.
• Impeller erosion. The constant force of the bubbles imploding may erode the impeller and pump housing.
• Seal or bearing failure. In extreme cases, when cavitation is causing significant damage to the pump’s components, you will find seal, o-ring, and bearing debris in the discharge fluid.
• Erratic power consumption. You’ll find you need more energy to get the same throughput if cavitation is an issue.
• Signs of anodised aluminium wear. If your pump is a positive displacement plunger pump, then look out for wear on the black anodised aluminium upstream from the outlet check valve as a clear sign of cavitation.

It’s worth noting that operating a centrifugal pump to the far right of the BEP can also cause cavitation. When the flow increases, the Net Positive Suction Head required (NPSHr) increases, and when it exceeds the Net Positive Suction Head available (NPSHa), cavitation can occur.

Checking for these symptoms through a reliable maintenance process is crucial in preventing further damage.

How do I fix pump cavitation?

If cavitation is suspected, there are three immediate steps to try to reduce it.

• Check suction lines for any restrictions, such as a stuck valve or blocked pipes, and remove these. 
• Move the pump closer to the liquid source to reduce the suction head pressure.
• Call the pump technicians at CAW: 072 470 4599 or pumpsdept@capearm.co.za

Also, routine pump maintenance, repairs, and testing are crucial in extending the lifespan of your pumps and preventing corrosion and wear and tear.

Trust the expertise of CAW’s pump technicians in ensuring the optimal performance of your pumps.

It is time your pumps operate efficiently and effectively

You can rely on CAW’s expertise and avoid and repair pump cavitation. We help you ensure the optimal performance of your system. Our team of pump professionals can help you with:

• Testing of motors and pumps and flow valves
• Pump maintenance and repairs

Ask for CAW. Eager to serve.

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