Successfully field tested in the UK

The situation
A combined sewage and storm-water pumping station with three dry installed sewage pumps was selected for field testing the Grundfos S-tube® impeller, because the installed non-Grundfos pumps were tripping on a regular basis due to excessive ragging. The pumps reportedly always blocked after a long dry period or after heavy rain.

The solution
Following another successful trial with the same water authority a second site was selected to trial the S-tube® from the pump position that suffered the most blockages. The Grundfos trial pump (7.5 kW) was matched as closely as possible to the non-Grundfos pump. The timing of the trial was also important to match when the incumbent pump had to be lifted and cleared on no less than 13 recorded and many more unrecorded occasions.

The outcome
The Grundfos pump was subsequently installed and in the following 13 months, no clogging or jamming incidents were reported. The decision was then made to order new, redesigned hydraulics to ensure that the pump would continue to meet any after new hydraulics were developed on the basis of wider field testing .
The pump was reinstalled at the site in the North of England, with new hydraulics and since then, the pump has been running with no reported blockages. The operator of the site considered the trial to be a success and continues to be very pleased with the pumps performance and reliability.