Hidrostal Non-Clog Pumps Solve Leaf Problem on the Grand Union Canal


Hidrostal non-clogging pump technology is being used to good effect at the seven consecutive pumping sites on the Grand Union canal, located between Radford and Itchington Bottom, to pump canal water back to maintain an adequate water level when required.

Following extensive site trials, British Waterways selected the Hidrostal axial flow screw centrifugal pumps to replace the existing pumps which suffered from blockages and subsequent high current trip outs caused by a high loading of leaves and other debris during the autumn season.

The requirement was to design, supply and instal the pumping equipment over a two week period without disrupting the canal operation. There was to be no canal closure and where possible the existing pumps were to be available throughout the duration of the works. The pumps had to be capable of handling leaf debris throughout the year without any impact on their reliability and they had to be capable of performing under all operating suction conditions down to a water level of 400 mm below downstream weir level.

A total of eight 250 mm NB Hidrostal axial flow screw centrifugal pumps were purchased. Seven of them were supplied and installed into prepared civil works to back lift water between locks, the eighth one being a common spare.

During original trials, to demonstrate the non-clogging characteristics of the pump to cope with canal debris, various items in addition to leaves, twigs etc. were presented to the pump including raggy material such as knotted rope.

The unique characteristic of the Hidrostal screw centrifugal impeller results in the pumps being able to handle the leaves and other canal debris without blockage and any significant rise in running current. It therefore proves that large volumes of water can be transferred efficiently without being compromised by solids handling capabilities, which is often the problem with conventional axial flow multi-bladed impellers.

Another feature of the project was the unusual logistics for mechanical installation of the equipment. All pumps and pipe work were installed within four days even though there was no vehicular access for six of the seven sites and equipment had to be transported along long stretches of canal towpath!

For more details contact Martin Walter: sales@hidrostal.co.uk.

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