Combating cavitation

When operators at an Australian sewage transfer station found serious erosion and cavitation damage to one of their key submersible pumps, they faced a lengthy lead time and costly spare parts to repair the pump. Enter Kelair Pumps, who had a different solution in mind, proposing to completely rebuild the pump, saving valuable time and money.

After excessive cavitation damage was found on the sewage transfer station’s KSB 440kW submersible pump, Kelair Pumps’ service team carried out a complete rebuild, the first for this size and type of pump.

Kelair Pumps Sales and Service Engineer Scott Norris said the pump’s volute and impeller were significantly damaged and required a complete overhaul.

“Basically cavitation is the development of bubbles in a liquid and it usually occurs when there is a rapid change in pressure, such as when the pressure is quite low.

“In this case these ‘bubbles’ formed around the pump’s volute and impeller, and when the pressure changed again the cavities burst, causing damage to the pump components.”

Mr Norris said cavitation damage in pumps can lead to serious problems if not addressed properly.

“Not only does the pump itself sustain damage, but its operations and energy efficiency are greatly reduced,” Mr Norris said.

“In this case, there was a 26-32 week wait to get a new volute and back plate for the pump, and purchasing these would be at extreme cost to the operators, so our skilled service team decided instead to overhaul the pump.”

Mr Norris said they decided to get the cavitation damage machined out using a vertical borer to get operations back on track quickly and restore the pump to optimal performance.

“Using a vertical borer allowed us to fill the machined area up with a heavy impact wear resist back to the original shape of the volute,” Mr Norris said.

“We then used a brushable ceramic to completely cover the volute to help increase efficiency.”

The pump overhaul took a total of three weeks, no longer than the average pump service, and helped the sewage transfer station to increase pumping efficiency.

“The station was extremely happy with the outcome because it saved them time and money, and they now have a repaired system that will continue to run at peak productivity.

“Kelair also identified serious cavitation issues with all three pumps in the station which can now be addressed following a pump and associated pipework analysis,” Mr Norris said.

Mr Norris said in order to avoid problems like these occurring, it’s important to ensure the correct pump for your application is selected initially.

However, rebuilds like the one Kelair performed for the sewage transfer station can also ensure a station’s pumping system continues to operate as well as when first installed.

“Our service division team works with clients to identify problems and then troubleshoot, repair and commission pumps both in-house and on-site based on the right solution for the job,” Mr Norris said.

To find out more about Kelair Pumps servicing business visit call 1300 789 466.

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