Molson Coors gears up at Burton-upon-Trent plant
18 May 2012
Burton-upon-Trent, UK - HES Tractec has supplied 20 Comer gearboxes to Molson Coors, the UK’s biggest brewer, to power the rotating floors of four germination vessels at its Maltings site, Shobnall, in Burton-upon-Trent.
The Maltings Tower, housing the germination vessels, stands around 230ft high, and has received regular maintenance and repairs since its construction in 1979, but in response to the rising cost of downtime, 30 years on, in May 2009, a major refurbishment programme began, one that included the upgrade of component parts.
With eight germination vessels in total across the site, if just one of those vessels were to fail for a day, an eight of our production capacity is lost, equivalent to 280 tonnes of barley, according to Steve Holyoake, project and electrical engineering manager at the Burton-upon-Trent site.
“There is a monthly servicing programme in place as well as condition monitoring for preventative and predictive maintenance but with the tower being over 30 years old, and many of the original parts now obsolete or difficult to procure, the decision was made to upgrade and modernise, using the latest in technology, both mechanically and electrically,” he explains.
On a site that is running 24/7, it is critical that the vessels stay in operation, Holyoake continued. The failure of a germination vessel, he said, “would not only cost the company a batch of malted barley, which is currently 50% more expensive than in 2009, but also the cost to remove wastage from site, disposal and replacement, costing tens of thousands of pounds.”
The project sub-contractor recommended planetary gearboxes, manufactured by Comer Industries and distributed in the UK by HES Tractec, to main contractors, Mectek Mechanical Services, a mechanical and electrical engineering company. A factor in the specification of the gearboxes was ability to withstand the extreme conditions of the germination vessels, similar to that of 100% humidity.
The vessels, stacked vertically within the 15-storey tower, are consistently held at 100% humidity to encourage the germination process. As the grain naturally generates heat the temperature inside the vessels has to be carefully monitored and controlled else the quality and rate of germination will be affected; as part of this process air is blown through the vessel whilst it is being humidified.
Each vessel is loaded with barley and this is germinated over four days. During this time the vessel floor rotates, at one of two speeds, fast for one hour during loading and stripping before slowing to its normal rate for production. Every 11 hours the floor rotation alternates between clockwise and anti-clockwise, this prevents the grain from matting, and clumping together.
A rotation takes around two hours. After the four days, the vessel is stripped and the barley is kilned for 24 hours. It is then stored, ready for transportation to one of Molson Coors UK breweries.
With the tower containing four germination vessels, each with a rotating floor, Molson Coors needed 16 Comer gearboxes in total, plus four additional spares. Each vessel floor works independently, with each gearbox driven through an electric motor. Steve and his team drive the motors using variable speed drives (VSD), this allows for a more accurate speed change. It also helps to reduce the output of the gearbox thus minimising unnecessary wear and tear. Mounted onto its own frame, the electric motor then powers the rack and pinion mechanism that runs the outer circumference of the floor, thus powering the rotation.
Mectek Mechanical Services completed the final vessel in December 2011, with one vessel delivered a week ahead of schedule - putting Shobnall Maltings back into production early.
“This is all proof of how the installation of new technology can improve both the operation and engineering of a plant as well as giving us the reassurance that if things go wrong we can react efficiently with immediate access to spares,” commented Holyoake.
In 2011, Molson Coors announced plans for the modernisation of the UK’s biggest brewery through a major, multi-year redevelopment programme that will see capital investment rise by £15m per year. The company’s portfolio of brands includes the best selling Carling, Cobra and Coors Light Molson Coors UK owns four brewing facilities, including Sharp’s Brewery in Rock, Cornwall, and employs 2,300 people in the UK.
