Watson-Marlow Pumps Eliminate Cavitation

Three Masosine SPS4 pumps from Watson-Marlow have enabled beverage manufacturer Halewood to eliminate cavitation and to reduce the unloading times for sugars and syrups. Cavitation and noise issues initially prompted Halewood to seek an alternative to its existing centrifugal pumps when decanting sugars and fruit-juice concentrates from tankers arriving at its UK headquarters on Merseyside. The company manufactures alcoholic drinks brands including Lambrini, Crabbie's alcoholic ginger beer, Red Square vodka and Reloaded vodka.

Halewood also distributes Lamb's Navy Rum and Tsingtao Chinese beer. From its headquarters on Merseyside, the company also manages movements from France to China, from Russia to South Africa and from Spain to Romania. Harry Anderson, the company's production trainer, said: 'Due to the high throughput of the Merseyside plant, decanting high volumes of liquid from tankers into holding vessels becomes a strategically critical operation. 'Until recently, the incoming sugars and syrups were unloaded using high-pressure hoses and centrifugal pumps.

'However, the pumps were cavitating and causing loud, knocking noises that could potentially irritate local residents. 'The pumps were also ageing and becoming too slow for our requirements,' he added. Cavitation is a typical problem in centrifugal pumps. As the impeller blades move through a fluid, low-pressure areas are formed as the fluid accelerates around and moves past the blades.

The faster the blades move, the lower the pressure around it can become. As it reaches vapour pressure, the fluid vaporises and forms small bubbles of gas - this is known as cavitation. When the bubbles later collapse, they typically cause very strong local shockwaves in the fluid, which are usually audible and may even damage the blades. One of Anderson's colleagues had used Masosine pumps in a previous employment and this became the suggested route forward, commencing initially with the sale-or-return trial of an SPS4 high-pressure model supplied by Watson-Marlow.

The Masosine SPS series of pumps features a sinusoidial rotor for gentle, low-shear product handling, while their heavy-duty construction means they can also handle high-pressure applications. 'Some of the cold syrups can be extremely viscous, so the pump would need to be fairly robust in its operation, but most importantly the issues of speed, cavitation and noise would need to be overcome,' said Anderson. The Masosine SPS4 eliminated cavitation and noise and reduced the unloading times for sugars and syrups. He continued: 'Using our old centrifugal pumps, it would take around 60 minutes to unload a tanker full of sugars.

'This has been reduced to 35 minutes using Masosine technology. 'Perhaps most impressive is that the time taken to decant a tanker full of fruit-juice syrup has been cut from four hours to just 45 minutes,' added Anderson. A total of three Masosine SPS4 pumps are now in operation at Halewood's Merseyside plant, where they have been used for 12 months at a rate of three to four times a day.