Having suffered repeated failures using conventional impeller pumps for the transfer of egg white in glazing processes operated at Cornish food manufacturer, Rowe’s the bakers the company turned to peristaltic pump technology from Watson-Marlow Pumps Group.
Originated in 1949 as a bakery in Falmouth, Rowe’s today comprises two production sites (both in excess of 20,000 sq ft), 17 retail outlets and more than 400 employees. As well as selling products such as pasties, savouries, sandwiches, cakes, breads, rolls and confectionary through its own stores, the company also supplies on a wholesale basis to virtually all the UK’s leading supermarkets.
Vedligeholdelse af et sådant levende fremstillingsvirksomhed udgør en reel udfordring for ingeniører som Phil Thomson, der er en del af et team, der hjælper med at sikre, at produktionen er både kontinuerlig og effektiv.
One particular recent problem on the pasty production line was causing the maintenance team more than a few headaches. Here, egg white is pumped into a glazing unit that is effectively a container with two integral spinners. The spinners create a mist that is allowed to fall and form a glaze on pasties passing below on a conveyor. Until recently, the company was using a conventional impeller pump for the task, but repeated failures and downtime became a growing cause for concern.
“The problem with an impeller pump is that it lacks a non-return valve, so if the process stops then the pump needs to be re-primed,” explains Mr Thomson. “Furthermore, because egg congeals, dedicated cleaning of both the pump and its connections is required. The escalating downtime meant ultimately that we had to find an alternative.”
Fortunately Rowe’s already had chemical dosing pumps from Watson-Marlow on site and so Mr Thomson was aware of the capabilities of peristaltic technology.
”Jeg hedder Watson-Marlow og de forklarede, hvad der pumper ville være velegnet til ansøgningen, endelig anbefale en 520 serie proces pumpe, de venligt leveret på lån til forsøgsformål.”
Described as the world’s fastest growing pump type, peristaltic pumps have no valves, seals or glands, and the fluid contacts only the bore of the hose or tube, eliminating the risk of the pump contaminating the fluid, or the fluid contaminating the pump.
Importantly for Rowe’s, Watson-Marlow pumps enable users to clean in-line at full velocity, without the intrusion of the bypass required by most other positive displacement pumps. The pump self-drains, has low-shear action and straight-through flow, and the tube is fully swept for superior hygienic performance. After a two-week trial at the company’s production facility in Falmouth, Rowe’s duly acquired the Watson-Marlow 520 series pump.
“While impeller pumps are cheaper, we could easily burn out four a year on a single production line,” says Mr Thomson. “If you add in the downtime and labour costs, peristaltic technology makes far more economic sense.”
As a further benefit, the peristaltic pump has also reduced the amount of foam caused previously by air entrapment in the impeller pump. Foam is classified as product waste and was being created at a rate of around 1 litre an hour.
“We couldn’t be more pleased with the peristaltic pump,” states Mr Thomson. “Considering all the costs we incurred with our impellor pumps I estimate that we will achieve payback on our investment within 12 months. In fact, we have just ordered a second pump for another glazing unit and hope to replace them all over the course of the coming two years.”
Watson-Marlow Fluid Technology Group
Watson-Marlow Fluid Technology Group (WMFTG) er verdens førende inden for niche peristaltiske pumper og tilhørende væskebane teknologier til fødevare-, farmaceutiske, kemiske og miljømæssige industrier