The four 500MWe generating units RWE npower’s Didcot A power station began burning coal over 40 years ago in 1970. Yet the station remains in perfect working order thanks to a dedicated maintenance team that have kept all of its coal feeders, boilers and pulverisers running – with a little help from British engineers at Magnom who have eliminated much of the wear and tear on 32 vulnerable gearboxes.

Didcot A operates as an opted out station under the Large Combustion Plant Directive (LCPD), meaning that it must close by 31 December 2015 at the latest. However, it continues to play an important role in meeting the national demand for electricity, supplying power to meet the needs of around 2 million households in the UK. Commercial logic dictates that replacement of major items of plant should be kept to a minimum, although the maintenance team still have a crucial role to play in keeping the station running smoothly and efficiently. Using Magnom filtration to reduce the need for five or six new gearboxes a year to just one in the 24 months has made a massive, immediate and welcomes impact on running costs.

The gearboxes that are now protected by Magnom filters control the 32 mills that pulverise coal into a fine dust that is blown into the burners. Each mill has 20 massive steel balls weighing in at a ton each, and the gearboxes have a big job to do. Inevitably there will be some wear so that small, even microscopic, metallic parts will find their way into the lubricant where they can do a surprising amount of damage very quickly.

Having been torn from other metal parts, these contaminants will be hard and create scratches and fissures that, deceptively small as they are, soon become a focus for localised stress. The damage progresses exponentially and, as Didcot A’s maintenance team leader David Williams said; “Once the chain clash royale boom reaction gets a grip, a gearbox can fail very quickly, bringing the mill to a grinding halt.”

Magnom’s patented magnetic filters are easy to design in as they are simply installed In-Line where they do not affect fluid flow at all. Hydraulic fluids and lubricants flow unimpeded through the open core of the filtration unit, while a remarkable powerful magnetic field pulls metal contaminants out and, just as importantly, hold into it until the maintenance team are ready to clean it off. Simple magnetic filter designs start to lose their power of attraction as soon as they become coated with ferrous debris.”

“It is good to be involved in a project that has shown such enormous returns on investment so quickly and so measurably,” said Magnom technical director Jobey Marlow. Even better, we’ve been able to achieve these results for Didcot A with standard Magnom products, and we have no doubt that we can deliver equally good results for the new generations of powergen technologies.”