Water & Wastewater Treatment

20 | DECEmbEr 2015 | WWT | www.wwtonline.co.uk Project focus: pumps Pumps ready to be installed ● Surface water pumps required because of mining subsistence ● High moisture readings in electrical equipment of old pumps called for replacement ● Health and safety concerns in wet well dictated method used, with two cranes deployed • Drivers riding basket. According to AxFlow, it needed very careful planning and control to get both the man riding basket in place to position the pump liing tackle and to carry out the pump removal and installation works with the two crane jibs working in such a small opening. "Our plan was to remove the old flange bolts and pumps and reconnect the new pumps to the existing pipework with new bolts," continues Redgrove. "The larger pump was standing on three feet on a concrete platform in the wet well and with the removal of some of the bolts the weight of the pump (4 tonnes) tended to pull it away from the flange on which it was fitted, putting the pump at risk of falling into the wet well. This was addressed by leaving some bolts in place until it was actually ready to li." The job of removing the old pumps and installing the new pumps took AxFlow three days to complete. The work however has continued, as following the refit, AxFlow were asked to take the old pumps to their Huddersfield Service Base for inspection. Redgrove continues: "We now have the pumps at our base and having stripped them down we have found that they were in pretty good condition, even aer 25 years of service. However, some oil and water has got into the motor windings, this appearing to be caused by perishing cable glands which can be relatively easily rectified. We further looked at replacing the usual components that can be subjected to wear, including bearings and mechanical seals and washed out the stator windings and reassembled the pumps. The impellers were in good condition as they clearly had a relatively easy life, even though they are in a high profile pumping station and over the years had been subjected to high levels of continuous operation." The two original pumps still operating at the Stillingfleet Pumping Station will be removed in the future to be replaced with the two overhauled pumps at AxFlow's Huddersfield workshops to finalise the current work on the pumping station. By Bryan Orchard The smaller of the pumps being li ed into position

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