Modern Mining April 2023

PUMPS AND VALVES

Close linkages in pumps, valve range adds value to solutions Customers benefit not only from the sheer range of pumps, valves and related equipment that Weir Minerals Africa offers, but from their careful integration – and the way they work together in process plants.

A ccording to Marnus Koorts, general manager pump products at Weir Minerals Africa, the diversity of products in a single company’s offering is only one contributor to successful solutions. As important is the fact that they inter act with each other – and can all be considered in designing the optimal flowsheet. “In a typical plant, the pumps and valves are within a few metres of each other – impacting directly on one another’s performance, lifespan and total cost of ownership,” explains Koorts. “A profes sional approach views all these items in relation to each other – that is, in an holistic way.” Over the years, Weir Minerals has made a con certed effort to ensure that its product portfolio comprises equipment lines that have a direct positive impact on each other in the working environment, he says. This has been an important aspect of the company’s global strategy to develop its all-of-mine capabilities. “With our pump range being among our core products, it is also important for us to understand how this equipment interacts with items immediately upstream or downstream in the flowsheet,” he con tinues. “For instance, the selection and operation of pumps must take into account the adjacent pipework and the types of valves you use – as these all affect the friction factor at play in the arrangement.”

He highlights the impact of valves, bends and elbows on the net positive suction heads (NPSH) available and the pressure that needs to be pro duced on the discharge. All these factors must be included in the necessary calculations when choos ing a pump. The type of valve being considered is integral to the selection of the pump. Professionals and technicians at Weir Minerals spend much of their time developing pump systems with customers, often working closely with plant engineers during the planning and specification process. Among the layout decisions to be made are those relating to the positions of the valves and bends relative to the pumps. “For instance, the customer needs to be aware that the distance between a valve and a pump must be at least one and a half times the diameter of the pump inlet – to avoid turbulence,” he says. “This tur bulence could have a negative effect on the pump’s efficiency, and will also increase wear.” Not only does Weir Minerals understand the intricacies of the pumps and valves in its portfolio, it also offers the rubber bellows that can be installed between these pumps and valves. The bellows are useful in dealing with misalignment and with expan sion in the pipework from changing temperatures. Importantly, they also help absorb startup or shut down shock that could crack or break pipes. “Our in-depth expertise on each of these prod ucts gives us insight into aspects like friction factors, which inform our recommendations on pump siz ing and selection,” says Koorts. “There is often not enough appreciation of the various issues to be con sidered in pump selection if the solution provider is not involved in all these different components.” In a recent installation, a customer required a third pump to be added to an existing two units in a sump on a large mineral processing plant in Africa. Weir Minerals Africa ensured that the third pump, a Warman® MCR was installed in a seamless inte gration that allowed the customer to operate any combination of the three pumps. Achieving this out come, however, was far from simple and required a high level of expertise and planning. “Using a dump valve in our design, we also enhanced the safety of the installation, so that several tonnes of slurry can be drained into the sump before any maintenance work on the pump

Marnus Koorts, General Manager Pump Products at Weir Minerals Africa.

Selection and operation of pumps must consider the selection of valves for optimum efficiency.

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26  MODERN MINING  April 2023