Mechanical Technology March 2015

⎪ On the cover ⎪

mining efficiencies

Above: Assembly of a 750 rubber-lined mill circuit pump at the Weir heavy bay foundry. Left: Weir Minerals offers a range of equipment solutions including hydrocylones, rubber lining, hoses and slurry valves.

performance. “The new Warman WRT ® impeller and throatbush upgrade kit has been used to make significant improve- ment to the design of the component combination,” Fawcett explains. These are integral components of the pump that impact on its hydraulic and wear performance. The Warman WBH ® slurry pump of- fers more than a dozen enhancements to the already state-of-the-art Warman slurry pump range. Here the main fo- cus is on meeting the productivity and cost demands of Weir Minerals Africa’s customers in different operating environ- ments. “This pump is destined to set a new benchmark in slurry pumping stan- dards, as the Warman AH range is widely accepted as the benchmark for many applications over the last few decades,” Fawcett says. The Warman SLR ® pump is designed specifically for medium-duty slurry han- dling where conditions are not arduous enough to justify a heavy-duty slurry pump. “We revisited the way our pumps are put together from a maintenance perspective. Traditionally, components were split radially, which was the easi- est way to strip a pump down and then reassemble it. Our particular innova- tion in this regard is to split the pump axially and fit it with a one-piece volute that reduces the assembly and risk of any potential component mismatch. The overall outcome is a pump unit with a significantly smaller footprint

hydrocyclones and Isogate ® valves. “The market has definitely changed. What is vital is the duration of any shut- downs and improving intervals between these shutdowns. Equally critical are the health and safety considerations around handling and repairing equipment.” Weir Minerals Africa has ISO 9001, ISO 14001 and OHSAS 18001 ac- creditation, and considers these factors in product development decisions and holistically in terms of repeatability and reliability. “Another major consideration is the environmental impact of the products we produce. A good example is being able to reclaim scrap metal from our customers and to reprocess that at our Heavy Bay Foundry (HBF) in Port Elizabeth and at our Isando foundry facility to limit the impact on raw materials usage and improve costs. The quality of our raw ma- terial stock is a major factor in ensuring our products meet stringent quality and performance standards,” Fawcett says. “We have sophisticated design pack- ages that allow us to optimise both performance and materials of construc- tion, which means employing the right material where it is required. In addi- tion, we investigate the root causes of wear occurring in specific areas and use this data for product and future product enhancements,” Fawcett says. Such enhancements flow through to the existing Warman AH ® range in order to increase efficiency and wear

to what is currently in the market.” Looking at general sump applications, Fawcett says the Warman WBV ® ultra heavy-duty range of vertical cantilevered slurry pumps has been launched and he believes that this too will be set to rede- fine these applications. The new design features internal agitation as opposed to a mechanical agitator attached to the impeller. The impeller has specialised vanes that take up a certain amount of the flow and divert it back into the sump to produce the agitation required. This feature is proving far more successful than the traditional mechanical or water assisted agitation mechanisms. Several of these next generation sump pumps are being trialed. “We have completed the test periods and have removed the pump units to evaluate the wear performance. The result has exceeded our expectations and it will be a game changer for our customers,” Fawcett says. “This development is emblematic of our approach to develop products for specific applications, rolling them out across our entire product offering and then standardising at a higher level. This means that all design changes are incor- porated into subsequent improvements and then finally in the standard product offerings. This, in turn, means that these improvements are passed on to all of our customers. Thus, as replacement compo- nents are purchased, the full benefits are realised,” Fawcett concludes. q

Mechanical Technology — March 2015

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