Process pumps reduce TCO for Westfield Medical

Westfield Medical, a UK manufacturer of single-use packaging solutions for hospital sterilisation and medical device applications, has fitted six of its machines with 530UN/R2 peristaltic process pumps from Watson-Marlow Fluid Technology Group (WMFTG), which have replaced rotary pumps after repeated failures were encountered. The move has led to a reduction in downtime at the company’s Somerset facility, and cut the cost of maintenance and replacement parts.

Established in 1984, Westfield Medical has grown to become a leading manufacturer of single-use sterilisation barrier systems. The company’s products include a comprehensive range of bags, pouches, reels, wraps, tray liners and accessories, which are used in over 90 countries worldwide.

Westfield Medical’s bespoke manufacturing service has been developed to produce specified sizes and special prints, as well as form fill and seal packaging, plain and printed sheet stock and a complete range of plain and printed top and bottom webs. The company’s in-house manufacturing capability includes multicolour flexographic printing, so that customer-specified designs can be produced on a variety of materials — including plain, crepe, registered adhesive and all-over coated papers, coated and uncoated Tyvek, and a variety of co-extruded and laminated materials.

When packaged medical items are used, to ensure the necessary levels of sterilisation are achieved, a special ink marker is deployed as an indicator. However, with a viscosity higher than standard ink, the marker was proving problematic to pump on six bag production machines featuring flexographic printing capability.

“We were using rotary pumps, but unfortunately they began seizing on an increasingly frequent basis; in fact, we began encountering issues every month,” said Ben Begue, Continuous Improvement Manager at Westfield Medical. “We experienced a particularly bad phase with the pumps in late 2018 and decided enough was enough. This led us to undertake some online research into alternative pumps, which in turn pointed to peristaltic technology.”

Westfield Medical contacted WMFTG and was recommended the 530UN/R2 process pump, one of which was supplied for a four-week trial. According to Begue, “Even after the first week we could see that it would be successful. We returned after Christmas and the machine with the 530 series pump started up straight away, whereas the other five printing machines all needed pump repairs prior to starting. The purchase price of the 530 pump is higher, but the savings associated with reduced downtime, maintenance and spare parts make the total cost of ownership [TCO] far less, especially across six machines.”

Westfield Medical made a commitment to buy six Watson-Marlow 530UN/R2 pumps, with the trial pump remaining on loan until deliveries commenced in March 2019. Since installation of the six pumps there have been no reliability issues, with the only replacement part being the Marprene tubing, which lasts about three months and takes just minutes to change.

Peristaltic pumps are positive displacement pumps which contain the fluid being metered or transferred within a flexible tube. Rollers in the peristaltic pump compress the tube as they rotate, creating a vacuum which draws fluid through the tube. Nothing but the pump tube touches the fluid, eliminating the risk of the pump contaminating the fluid or the fluid contaminating the pump. Fluid is drawn into a pump tube, trapped by the pumphead roller and expelled when the next roller passes over the tube. As the rollers rotate, a vacuum is formed in the tube, pulling in more fluid, for the next roller pass. The complete closure of the tube when is it occluded (squeezed) between the roller and the track gives the pump its positive displacement action, preventing backflow and eliminating the need for check-valves when the pump is not running. The pumps are virtually maintenance-free as there are no seals, valves, diaphragms or rotors to leak, clog or corrode.

At Westfield Medical the 530UN/R2 pumps are used in continuous mode, although the actual flow rate is quite low. Since installation and set-up, each pump has been left to run day in, day out, without the need for any adjustment, even in hot weather, when the company dilutes the ink marker slightly to compensate for thermal effects.

Watson-Marlow 530 series pumps are intuitive, secure and maintain process integrity in applications with flow rates up to 3.5 L/min at 2 bar pressure. Various drive and pumphead options are available, along with a wide range of tube sizes and materials.

As a result of the success achieved with the 530 series pumps, Westfield Medical plans to embark on a trial with a larger 730 series pump on one of its bag production machines. Begue explained, “The machine uses an air-operated diaphragm (AOD) pump to apply glue that seals the bottom of the bag. However, we’re having trouble with the actual diaphragm, which is perishing. Although we are not quite ready yet, we’re very keen to try the 730 series pump from Watson-Marlow, for which we have high hopes.”

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