Gear solution improves efficiency of rebuilt hoist

Edited by the Engineeringtalk editorial team Jun 4, 2003

David Brown Engineering has supplied a gear solution to Qualter Hall and Company of Barnsley to be incorporated in a new blast furnace skip hoist for the Corus Port Talbot steelworks.

David Brown Engineering has supplied a gear solution to Qualter Hall and Company of Barnsley to be incorporated in a new blast furnace skip hoist for the Corus Port Talbot steelworks.

The gear units operate under highly variable loading conditions which require careful design and engineering of gear teeth to ensure efficient working across the range.

David Brown, a Textron Power Transmission company, used a specially developed computer program to plot the various loads that the hoist would be required to handle and the effects of deflection.

The company then used state-of-the-art manufacturing techniques to produce gearing which improved considerably on the original design.

The 22t complete gear drive with an overall ratio of 42.5:1 was designed as a 'drop in' solution.

Great care was required in the design of the bull wheel because, with the varying loads, the bull wheel needed to interface in all deflection conditions - a tall order given the range involved.

The most obvious change to the design of the bull wheel was the change from shaft mounting to a drum flange mounting in order to minimise deflection, but the wheel itself also contains considerable innovation and design technology.

In addition to the final drive bull wheel and pinions, David Brown supplied two double reduction single helical primary gear units each with a double helical (DH) pinion fitted onto the output shaft.

The DH pinions mesh with the bull gear mounted onto the winch drum.

The principal design criterion of these units was to produce gears which fitted into the available envelope and here too David Brown produced highly capable 'drop in' units.

A replacement furnace skip hoist was required for rebuilding the No 5 blast furnace at Port Talbot, following the unprecedented explosion at the furnace in November 2001.

Corus specified equipment which copied the layout of the skip hoist installed in 1992 on the refurbished No 4 furnace.

The skip hoist is used to load the blast furnace with all the elements required to make iron.

Twin motors drive two gear units which in turn drive the two pinions and the single bull wheel.

The weight of the various loads varies considerably due to the different amounts required of each element and the varying mass of the different substances.

Consequently, loads vary from 9 to 25t and occasionally 35t.

The overload capacity is 41t.

In addition, the hoist is designed to operate with two drive motors, each of which is on a 100% redundancy basis, ensuring that should one motor fail the other will be capable of continuing the loading of the blast furnace.

The skip hoist itself was built by Qualter Hall of Barnsley, a company with over 100 years experience in the design, manufacture and installation of state-of-the-art hoisting, winching and haulage systems.