The filter plant is being used to capture the fumes created during the desulphurisation process, and has been built in order to improve the plants environmental performance. The door drives needed to be compact yet still able to provide high torque output and low energy input, combined with strength and durability.
Corus Scunthorpe is one of the largest steel production sites in the UK, producing plates, sections, wire rod and semi-finished steel using the BOS method. As well as reducing dust emissions, the new technology aimed to create a more pleasant working environment for employees and helped to speed up the steel-making process.
Previously the plant used two wet scrubber systems to remove the fume generated by the iron preparation and desulphurisation processes; however these were becoming outdated and inefficient. To replace the two wet scrubber systems one new bag filter plant was commissioned.
The desulphurisation process involves coinjecting lime and magnesium into a ladle of molten iron, the sulphur in the iron reacts to this and rises to the surface in the form of a slag. Once the injection treatment has been completed the slag is skimmed off the ladle. The desulphurised iron can then be taken into the BOS vessels to be converted into steel.
It is during the desulphurisation process that the fumes generated need to be extracted and cleaned efficiently. Doors have been designed that close to contain the fumes during the process while the extraction system draws them away. The gearboxes required to drive the doors needed to be compact in order to fit into the available space whilst providing the strength and torque required to shut the heavy doors.
The company that was commissioned to build the filter plant turned to Brevini to provide a drive solution to the doors, they were able to design a solution that met all the application requirements using its Posiplan range of planetary / helical hybrid gearboxes.
Jon Snaith, General Manager – Sales & Marketing of Brevini UK Ltd.: “The Posiplan gearbox offers the best of both worlds, delivering higher capacities from smaller units which allows for a significant increase in capacity over a more traditional design. Different sized motors are available and selected using motor performance curves to ensure maximum efficiency in realised.”
The Posiplan hybrid gearboxes combines the efficiency of low weight, high reduction ratios of planetary gear stages on the input side with the higher capacity, strength and durability of bevel helical gears on the output; this is ideal for medium to large sized industrial applications. The input end employs planetary stages where higher speed and compactness are a major advantage while the output uses a helical stage as it is slower and has higher torque.
Brevini supplied four Posiplan gearboxes for the Filter Plant project, each of which have a reduction ratio 2813.5:1 and is fitted with a tiny 1.5 kW motor. This provides an output torque of 22,000Nm and a low speed of 0.5rpm. The gearboxes are shaft mounted which means they are tougher than exposed transmission alternatives such as belts, chains and pulleys; ideal for applications that require 90° operation or survival in harsh environments. The gearboxes use the latest labyrinth sealing technology and high performance bearings which extends operating life in the harshest environments.