Until recently, Severn Trent Water has always preferred to use conventional metering pumps, but this is set to change with the implementation of a 520 DuN/REM high pressure peristaltic pump from Watson-Marlow Pumps Group.
The pump has met the immediate needs of three chemical dosing schemes implemented at various Severn Trent Water facilities. Deployed as part of a temporary dosing rig constructed by engineering group, Costain, the pump’s success is helping to pave the way for future consideration of peristaltic technology.
According to Paul Pearson, process commissioning engineer at Costain, Severn Trent Water’s preference for metering pumps has been relaxed, giving Costain the opportunity to run trials using a peristaltic pump.
Pearson says there are at least a further half-dozen such applications planned for the coming 12 months, all of which will also use peristaltic technology supplied by Watson-Marlow, although some are larger schemes which might demand a higher flow rate specification than the existing 520 DuN/REM model (108l/h at 4.1 bar).
So far, the peristaltic pump has been used for ferrous chloride and ferric sulphate dosing and has also been used to dose with lime for pH correction.
“In my mind there are so many things that can go wrong with a metering pump,” said Pearson, “but with peristaltic, the potential for failure is reduced massively because there are no valves, stators, diaphragms, seals or glands. It makes maintenance extremely straightforward. Only the tubing requires replacement, which is quick and inexpensive…”.
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