Egg yolk handling challenge is met by peristaltic pump technology

1st April 2013

An 840 Series hygienic peristaltic pump from Watson-Marlow Bredel is being used by a Japanese food processing company to pump egg yolks and whites through a chilling process before despatch to food manufacturers who make extra-thick omelettes that accompany sushi.

The pump processes the egg yolks with a 70 per cent unbroken rate, allowing for a better quality end product and offering a 350 per cent improvement on the company's previous pump.

Chilling approximately 60000 egg yolks and white every day is no mean feat, but demand is such in Japan that a solution to this curious processing dilemma was required urgently.

Sushi in Japan is traditionally served with omelettes cut into portions measuring up to 2cm thick. To guarantee that the quality of the omelette matches that of the fine sushi on offer, producers demand as many unbroken egg yolks as possible.

However, using a conventional sine pump at the food processing company, only a 20 per cent of yolks were making it through the pump without damage. The situation had to improve if existing order levels were to be maintained.

International sales and support for Watson-Marlow Bredel pumps is provided in Japan by Iwaki Pumps, a 700+ employee company that has been established for over 50 years. Iwaki was challenged by the food processing company to do better and achieve at least 65 per cent undamaged yolks after pump transfer.

The pump recommended for the job was the 840 Series peristaltic metering/transfer pump from Watson-Marlow Bredel, largely because of its ability to meet gentle, yet high flow hygienic applications. The only snag was the lack of reference cases. No one was aware of ever previously trying to pump egg yolks without damage. The trial was about to break new ground.

Peristaltic pump technology is hygienic by its very nature because nothing but the hose or tube touches the fluid, eliminating the risk of the pump contaminating the fluid, or the fluid contaminating the pump. Peristaltic pumps work by compressing a tube element between rotating rollers. In between each roller pass, the element recovers to create a vacuum and draw in fluid, giving the pump its positive displacement action, preventing backflow and eliminating the need for check-valves when the pump is not running.

Hygienic features of the 840 Series include clean-in-place and steam-in-place sterilisation at full velocity without the need for bypasses, and stainless steel connectors certified to 3.1.B BS/EN10204. The 840 Series offers flow rates between 653 and 8140litres/hour, while Bioprene tubing is available in two hardness values to provide 2 or 3.5bar pressure. Furthermore, the pump is quiet at less than 75dB(A) at one metre.

The inverter-controlled pump arrived at the Japanese food processing company and, even though the layout of the output hose was far from ideal, the trial commenced. Starting from a low speed the pump velocity was increased to 20rpm, which gave the desired flow rate of around 1000litres/h. It was evident immediately that a far higher percentage of egg yolks remained intact after pumping than was previously the case.

A surprised and delighted number of processing staff assessed the yolks and confirmed about 70 per cent were undamaged.

The company is now in the process of upgrading its processing operations to incorporate the 840 Series peristaltic hygienic pump from Watson-Marlow Bredel.






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