Mechanical Technology Archive

Howard Jones, dewatering product manager at Weir Minerals Africa, tells of an Envirotech Uniglide pump installed in 1976 that is still running and supported today.

Weir Minerals Africa was recently called upon to assess a Uniglide horizontal split case pump that had reached its perceived end of life at an iron ore mine in the Northern Cape of South Africa. The pump, which was originally installed in April 1976, formed part of a larger order of Uniglide pumps. In total 22 of these dewatering units were supplied to the mine by Salsa Weir, which later became Salweir before being incorporated into Envirotech, which became part of Weir Minerals in 1994.

The 40-year-old Uniglide pump was being used in a dewatering application in the screening plant at the mine and is being replaced with an identical unit.

Weir Minerals Envirotech UNIGLIDE PUMPSJones says that in the past, Uniglide pumps had established a reputation under the name of Harland and these units are still sometimes referred to as such today, although this is not factually correct.

He notes the significance that pumps manufactured and sold into industry in the 1960s and 1970s are still operational today. “This is a testament to the structural integrity of these pumps, many of which are still achieving astronomical operating hours,” he says, adding: “There is a need to assess the condition of these aged units, however, to ensure that there are no catastrophic failure risks”.

“We have started seeing these very old pumps coming in for refurbishment, and Weir Minerals Africa is in an excellent position to cater for the level of technical support required to keeps these pumps functionally operational. Through the extensive technical knowledge residing in the company, we have the ability to undertake repairs as well as the complete refurbishment of these old pumps,” he says

“Important to customers is that, where the pump is beyond repair, we can offer a replacement without the need for any major changes to pipework,” Jones adds.

He says that the move by mines and process plants to review the functional efficiencies of pumps is in line with current economic pressures. “Operations need to optimise, drive cost efficiencies and lower total costs of ownership wherever possible,” he suggests.

The oldest pump that Weir Minerals Africa has on record was manufactured and installed in 1953, although Jones does caution that there may well be some that are older than this. This Uniglide horizontal split case pump was installed at Iscor Works in Pretoria and was probably used for the circulation of cooling water in the iron and steel works. It was capable of pumping 260 ℓ/s at a head of 110 m.

He explains that the Uniglide, a heavy duty horizontal split case dewatering pump, is typically used for water transfer and bulk water supply, which means that there are large populations in the water utilities, in wash water applications in process plants, in mine water applications such as refrigeration plants and in the agricultural sector.

This pump line-up, with 40 frame sizes manufactured in South Africa, covers an extensive range of duties, allowing the end user to select the most appropriate pump to ensure efficient operation at that application’s requisite duty. The range offers capacities of up to 3 600 m3/h at heads of up to 170 m.

The pumps can be mounted either horizontally or vertically to accommodate the application installation requirement, and when mounted vertically a smaller footprint results, facilitating greater flexibility in plant layout.

Pumps on larger frames are equipped with a double volute that reduces radial hydraulic thrusts, thereby extending bearing life. This also allows operation over a wider range of the pump curve and enhances the total life cycle of the pump.

Ease of maintenance is assured as the rotating assembly is easily removed without disturbing the pump alignment or pipework. This facilitates repair on the pump and minimises the downtime required for complete rotating element change-outs.

Jones says that while materials of construction have been improved significantly over the last 30 years, it is still the inherent robustness of the Uniglide pump range that has seen these units achieve in excess of 38 years of reliable service before needing to be either completely refurbished or replaced.

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