Success at E & E

Acids, alkalis and plastic sacks: solving a difficult problem

Where a variety of other pump types had been tried and have failed, a Watson-Marlow Bredel SPX50 hose pump now handles a difficult effluent pumping duty at E & E Limited, chemical suppliers, South Kirkby site.

The problems at E & E lay in the nature of the effluent produced, which can be acidic or alkaline with up to 10% solid content. The fluid effluent often consists of sodium bisulphate, caustic potash, hydrochloric and sulphuric acids in varying concentrations. These aggressive chemicals, together with abrasive substances such as calcium deposits, grit and sludge, as well as extraneous items such as wire, plastics sacks, tie wraps, labels and bottle tops, create a seemingly unlikely mixture for a pump to handle.

All effluent and surface run-off from the entire site drains into a centrally located, six metre deep collection sump. Operating automatically under the control of high and low level float switches, the Watson-Marlow Bredel SPX50 pumps from the sump against a head of approximately three metres, to the Company's effluent treatment plant.

Other pumps tried on the duty included submersibles, air operated double diaphragm and various plastic-lined and all plastics centrifugal and positive displacement designs. All were unable to cope to varying degrees, with the combination of solids, acids and other aggressive chemicals. As well as corrosion and abrasive wear of these pumps, pump blockage was a frequent problem.

Installed in September 1999, the Watson-Marlow Bredel SPX50 (50mm bore hose) provided the answer. With its "straight through" flow path there are no vanes, valves, rotors or pistons to corrode or impede the flow of solids and the heavy duty, abrasion resistant, reinforced EPDM hose is the only component in contact with the effluent. The occasional hose blockage is inevitable when handling materials such large and irregular shaped solids, but can often be cleared by simply reversing the pump.

Pump output is 3 m³/h; the hose is changed at six monthly intervals as part of the plant's routine maintenance programme.

The Watson-Marlow Bredel range of heavy-duty hose pumps is produced in sizes up to 100mm i.d hose for outputs up to 80 m³/h and pressures up to 16 bar.