MechChem Africa

In celebration of the 80th anniversary of Charles Harold Warman’s first Warman® Pump, Pieter Jordaan, Weir Minerals Africa sales director for Africa and the Middle East, talks about the history and evolution of the Warman slurry pump. 

Warman 80 Weir Minerals Pieter JordaanDr Charles Harold (CH) Warman started his career as a young engineer in the gold mines of Kalgoorlie in Western Australia in 1934. “While working on the mine, CH Warman came up with the concept of a slurry pump with replaceable liners,” says Jordaan, “the idea being that, while material will always wear away, if a liner is used the worn material can easily be replaced,” he adds.

Charles Warman also realised that by engineering a pump with individual components that are easily replaceable, he could extend the life span of the pump. “That way, a long life can be achieved from each set of wear components as well as the pump casing,” Jordaan explains, adding that, in design terms, this is called maximising the wear to structural material ratio.

“If the wear to structural materials ratio is low, the material available for wear will have a relatively higher cost, as a larger portion of the component will not be utilised for wear but rather for structural purposes. Using a higher ratio of wear material, therefore, reduces the total cost of ownership of the pump,” Jordaan tells MechChem Africa.

“This was CH Warman’s revolutionary idea. He invented the concept and, in 1938, used it to build the first ever slurry pump with replaceable liners.

“From there, he started a business called Warman Equipment, which attracted interest from mines all over the world, including Africa. Then in 1969, Charles Warman sold a portion of Warman Equipment to the mining company Peko-Wallsend, while Charles Warman himself kept the CH Warman Pump Group portion of the company as an exclusive operation for Africa and the Middle East. “The reason he kept it was because of the aggressive ores found in Africa. Charles Warman was passionate about R&D and he believed that if he could develop pumps for African ores, then these would be better suited to mining operation everywhere else in the world,” Jordaan explains.

In 1999, the UK-based Weir Group acquired what was then called Warman International. The CH Warman Pump Group in South Africa remained independent, until 2007, when it too was brought into the Weir fold. “And, along with Envirotech, which has been part of the Weir Group since 1996, this now constitutes the current pump offering of Weir Minerals Africa,” Jordaan informs MechChem Africa.

Continuous improvement

Early development by Charles Warman quickly led to the development of the Warman® AH centrifugal slurry pump range, which has been the leading Warman pump for over half a century. “Using feedback from our customers and data from engineers, we have continued to upgrade and improve this heavy duty pump over the years, by targeting important issues such as wear life, hydraulic design and the material composition of the liners.

“At the starting point of pump development is hydraulics, to keep the transfer of kinetic energy to fluid flow as efficient as possible. Impeller design, internal profiles and the positioning of the wear materials to reduce wear rates and ensure the maximum possible wear life are all critical design considerations.

“In principle, we are always striving to achieve the longest possible period between liner replacements. The longer this period can be stretched, the lower the operational costs of the pumping operations will be. Both the hydraulic efficiency and the materials used are critical in achieving this,” he explains.

“Some applications work very well with rubber liners, but others need metal liners – and if these are swapped around, the results may be disastrous. Today we have numerous different material options, hard-chrome metal, corrosion-resistant steel, natural and synthetic rubbers, polyurethanes – and we even offer some ceramic liner components,” Jordaan tells MechChem Africa.

“All of these are carefully chosen and tested for use in specific applications to get optimal wear from the liners for each client’s slurry pumping application,” he assures, adding: “While energy efficiency is always a driver, slurry pumping is not a one-solution technology. You have to match the whole pump to the medium being pumped and to the conditions that apply on each mine.”

In recent times, Wear Reduction Techno­logy (WRT) has been introduced to the AH slurry pump range. “WRT is a series of enhancements to our AH pumps – and the technology is backward-compatible with our AH pump casings. Due to the enhanced hydraulics involved, applied in the same liner materials, we have seen significant improvements in wear life on AH pumps that have had WRT incorporated into them,” says Jordaan.

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