Medium pressure pumping system used in coating aluminium process

Paul Boughton

Used to power the cleaning station on the tension levelling line at Taiwanese mill. Michael Sherman reports.

Aluminium is used in a huge variety of products, due in part to the wide range of surface treatments and coatings that can be applied to it as part of the manufacturing process.

For one aluminium producing company in Taiwan the demand for these products has led to a huge expansion project to increase production of aluminium plates, sheets and coils. As part of the new installation a high pressure pump unit from RMI Pressure Systems will be used to power the cleaning station on the tension levelling line.

Aluminium strip processing plants use tension levelling to correct shape defects in the metal strip that have been induced by upstream rolling processes as well as to alter or improve inconsistent mechanical properties within the strip. The strip material is subjected to a series of alternating bends under significant front and back line tension before moving on to be coated or passivated.

The investment in new rolling mills, tension levelling machines and annealing equipment will see a large part of the design and installation work completed by JP Steel Plantech, a company which provides iron and steel engineering services to manufacturing plants looking to install new plant and equipment. When designing the cleaning station, it was decided to award this contract to RMI.

RMI designed a medium pressure pumping system, which is similar to a high pressure descaling system, to be used in the coating process to ensure that the aluminium strip is as clean of impurities and imperfections as possible. The system incorporates a variable speed drive (VSD) to control the pump speed which provided a gradual pump start as well as improved energy consumption, reducing operational costs.

The new pumping system also includes a comprehensive filtration package to ensure that the water being used is itself free from impurities that would otherwise be incorporated into the aluminium. Consisting of two Trimax S75 pumps, equipped with 55mm rams and powered by 55kW motors, the design was specifically built for this application to meet the client's criteria.

The pumps are operated on a duty/standby arrangement to pressurise the cleaning water, which is pre-heated to 50°C, and deliver 300 litres per minute at maximum pressure of 70 bar. The complete package was assembled by RMI and included monitoring and safety systems to ensure reliable and efficient operation.

Mike Sherman, RMI Marketing Manager, comments “As one of the world’s leading manufacturers of high pressure, high flow pumping systems, RMI has been designing solutions for the metal processing industry for many years.  As with many applications unplanned downtime is very expensive, so reliability is an essential quality required of our equipment. We have an enviable reputation for designing efficient and reliable equipment, which has been used across the world in a wide variety of industries for many years."

The whole expansion project at the aluminium producing company will cost over US$ 300 million and will see overall production increase to 100,000 tonnes per year. It is therefore very important that the new production line delivers high quality materials in the most efficient manner in order to recover these costs. By investing in a cleaning station that is extremely reliable and which also delivers efficient running costs, the client has made a major step in seeing a return on this investment.

Michael Sherman is with RMI Pressure Systems RMI Pressure Systems,Manchester, UK.