RMI Pumping System Gets Through UK Coal Trial Run

Special design features and enhanced performance capabilities have proven effective in the field trial of a high-volume, high-pressure pumping system developed by RMI Pressure Systems Ltd. of Manchester, England (U.S. office is in Jasper, Ala.).

The Quinmax S500 pumping system is a relatively recent addition to the company's S-series equipment for heavy-duty industrial applications such as mining, oil and gas, power generation, and large manufacturing operations.

The Quinmax S500 pumping system generates flow of up to 1,100 L/min and pressure to 1,000 bar.

The Quinmax S500 pumping system generates flow of up to 1,100 L/min and pressure to 1,000 bar.

It was tested for a year in a longwall mining operation in England by UK Coal Ltd. (In longwall mining, a panel or "slice" of underground coal, up to 3 ft thick and 2.5 miles long, is mined.) According to an announcement released by RMI this month, the pumping system maintained high rates of flow and reliability during the trial.

The Quinmax S500 also contributed to significant operational economies. UK Coal mined the entire face of a longwall mine with the one pumping system, which reduced energy costs by £24,000 ($39,600). The potential for savings is important to the company, owing to the fact that most coal used for power generation in the United Kingdom is imported, the international price of coal is low, and the company must price its coal in U.S. dollars, a lower-value currency than the British pound.

As a result of the trial, UK Coal certified RMI's pumping system for use in the company's mining operations above and below the surface.

RMI incorporated a number of design features in the system. Among these is the enclosure of all working parts, which significantly reduces maintenance problems caused by dust, dirt, and other environmental contaminants.

S-series models use crankshaft-driven reciprocating pumps. These are usually powered by three pistons, but the Quinmax S500 has five on the crankshaft. Benefits of this include high flow rates (up to 1,100 L - 290 gal - per minute), greater pressure generation (as much as 1,000 bar in some installations), and a 40 percent reduction in crankshaft load, which in turn reduces bearing stress and contributes to reduced maintenance. The five-piston array also means the crankshaft can turn more slowly than a three-piston version, which decreases wear and noise and achieves longer pumping strokes.

The crankshaft is machined from high-tensile steel for durability; the pistons are manufactured from an advanced ceramic material and have Kevlar (polyaramid) packing seals. The bearings are made of bronze.

Digital and analogue readouts are included for machine monitoring, and Quinmax models can be equipped with ODIN (On-Demand Intelligence), an RMI-developed control logic system for mining (and other applications) that interrogates components in longwall shearing machinery. By monitoring machine performance, ODIN anticipates the required movement of roof supports and calculates the subsequent demand for hydraulic fluid this will generate from the pumping system. This reportedly improves the responsiveness of the Quinmax S500's variable-speed pumps and modulates pressure while reducing operational cost.

While the system is described as "intrinsically safe" for onshore and offshore use, modifications are available when required to meet the specific safety standards of an industry. These include explosion-resistant fittings and a nitrogen purge for the variable-frequency drive.

Indian steelmaker NMDC installed 11 RMI pumps in its thin-slab descaling plant.

Indian steelmaker NMDC installed 11 RMI pumps in its thin-slab descaling plant.

RMI also made the Quinmax S500 modular to simplify part replacement. The company adds that some maintenance can be conducted while the pumping system is in operation.

The S500 is relatively compact, at 2,900 mm long and 1,275 mm high (114 by 50 in). S-series models are powered by motors ranging from 300 to 450kW, and have ram diameters of 50 to 80 mm (1.9 to 3.1 in).

RMI maintains that these and other design features contribute to a reliability rate of 98 percent.

UK Coal isn't the only company that approved the pump. Earlier this year, Indian steelmaker NMDC Ltd. acquired 11 of the pumping systems for a descaling plant at its thin-slab production line in Nagarnar, Chhattisgarh, India.

The pumping systems generate high-pressure water flow through special headers to douse hot slabs after production. This rapidly cools the steel and removes scales from the final product. Without an effective descaling operation - and the high-pressure pumping systems that make it possible - imperfections would appear in the steel that could cause it to be scrapped or sold at lower prices. Scales also increase wear on the rollers that transport the steel.

The 11 pumps were specified to achieve a nominal output of 520 L (137 gal) of water per minute at a pressure of 400 bar.

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