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Process Equipment Update


to the acquisition of the pump, along with two further models for the other filter mains (Fig. 1). The SPX25, which features a rugged hub with twin-


bearing rotor at its core, combines the advantages of bare- shaft construction with those of a close-coupled pump. The pump bearings absorb the forces occurring in the pump centrally, placing no load on the gearbox bearings, which means no coupling, no alignment and no heavy-duty base plate - resulting in less installation time, less maintenance and lower costs.


Savings in repair costs


Food manufacturer, Greencore Group has also achieved significant savings in downtime and repair costs on the water treatment plant at its Greencore Grocery site in Selby, North Yorkshire, England, thanks to the installation of a Bredel SPX50 high pressure peristaltic hose pump from Watson- Marlow Pumps Group. Greencore Grocery, one of the UK’s leading


manufacturers of bottle/jar-packaged recipe products, producing a wide range of both branded and customer own- brand sauces, pickles, and soft drinks. The cleaning and change over process between different


products, produces a small quantity of liquid waste (food effluent). This can lead to significant fluctuations in pH levels, from 4 up to 12 in some instances. Until recently, pH levels at Selby were corrected using 32


per cent caustic soda (sodium hydroxide - NaOH) through the facility’s water treatment plant, which is owned and operated by United Utilities, the UK’s largest listed water company. With Greencore responsible for consumable costs, a cost-down exercise was commenced to seek an alternative to NaOH. “The Greencore Grocery facility at Selby is a high volume


plant where there can be between 10 and 26 ‘washouts’ a day depending on order schedules,” says Peter Wadsworth, craft technician at United Utilities. “In order to find a more cost effective method of correcting the pH in the processing machinery, we trialled a product called Mag Mex 1060 which is a magnesium hydroxide solution [Mg(OH)2


], to correct the


pH levels. Carrier water is used to dose the Mag Mex into the system


at Greencore Grocery, but to do this effectively a suitable pump is required. “To be honest we started off using fairly cheap and


cheerful dosing pumps, but this proved to be inefficient as we spent two days a week repairing them,” says Wadsworth. “Because magnesium hydroxide has low solubility in water it makes for a pretty abrasive fluid. We found the grit would attack the mechanical seals and drain plugs on the dosing pumps, thus requiring repair.” It so happened that one of United Utilities sister sites was


using a peristaltic pump from Watson-Marlow, and this was subsequently recommended to the process engineering team at Selby.


As a result, a Bredel SPX50 high pressure peristaltic hose


pump (50mm diameter) was installed and ever since there have been no abrasion issues causing downtime or repair (Fig. 2). Verder Pumps South Africa (VPSA) says that the use of


its VF125 pump range has contributed to cost savings and increased productivity at platinum mines.This was seen at


Fig. 2. Since installation of a high pressure peristaltic hose pump there have been no abrasion issues causing downtime or repair.


Process engineering company DRA was appointed project engineer on the project and approached VPSA to assist in the design of six thickener transfer pumps. “No other pump on the market is able to transfer the slurry without a second pump station, which would come at a significant cost to the mine and would probably take more time to process,” says DRA project engineer Thys de Beer. There are currently 24 VF125 pumps operating at


37 kWh at the platinum processing plant. The design for these pumps included installing pulsation


dampeners to help decrease the pressure build-up in the pipeline, says Louw..


Increased life expectancy


The build-up in the hoses is eliminated by using rubber Verderflex hoses that are designed to increase life expectancy and production performance. The Verderflex hose pumps are designed to handle tough operating conditions; they reduce downtime, decrease maintenance costs and provide easy operation and reliable solutions in difficult pumping environments. l


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a precious-metal producer’s concentrator upgrade project, near Rustenburg, where VPSA was required to upgrade the thickener transfer pumps for higher production capacity, says VPSA consultant Daan Louw. The upgrade was possible as the pumps are able to pump slurry with 1.7 specific gravity and at a flow rate of 60 m3


/h


over a distance of 690 m, with a height of 30 m. This was the most difficult application for a peristaltic pump that VPSA ever had to deal with, he says. The VF125 thickener pumps resulted in cost savings and increased production capacity, explains Louw.


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