DOWDING & MILLS' RAPID REPAIR CEMENTS RELATIONSHIP

Time pressures and complex logistics were amongst the issues Dowding & Mills Engineering Services had to overcome in order to minimise losses for Rugby Cement when the crusher at its Rugby site broke down, resulting in a total shutdown of production.

The breakdown occurred when the shaft on the crusher, which is the only one of its kind in the world, broke into two pieces. Dowding & Mills' Weedon branch was called in to view the damage, but due to the dimensions of the steel rotor shaft, which measured 3,500 mm in diameter, 6,500mm in length and weighed 62 tonnes, they called upon Powergen to help. The Weedon branch has developed a working partnership with Powergen over a number of years, working together on similar projects where a large 75 tonne crane has been required.

As a result of the time sensitivity of the project, a dedicated working party was drawn together from Rugby Cement, Dowding & Mills and Powergen to oversee the work, with input from the original equipment manufacturer. The group met on a daily basis and worked very closely together to minimise the losses for Rugby Cement.

"Dowding & Mills was the obvious choice for us when it came to repairing the crusher," commented Colin Mousley, engineering manager at Rugby Cement. "We have a long history of working together and knew that Dowding & Mills could put the best team together to repair the crusher to the highest standard in the minimum time. The repair time was particularly crucial as the breakdown meant we had to stop production completely and were losing money every day that the shaft was out of action."

The repair job, worth £550,000, involved manufacturing a new shaft to replace the original design, removing the discs from the original rotor and modifying them for use on the new shaft, shrink fitting the modified discs on to the shaft and welding it. The bearing areas and drive couplings were then machined using a large lathe at Powergen's Coleshill plant.

Commenting on the project, Andrew Duffield, works manager at Dowding & Mills' Weedon branch, said: "Pulling together a team from the three companies to oversee the project was key to the success of the work. In addition to repairing the part in eight weeks by working 24 hours a day, seven days a week, we incorporated some new parts to help reduce the likelihood of such a breakdown happening again."

This has obviously proved to be the case, as Colin Mousley concludes: "Dowding & Mills exceeded our expectations, they responded brilliantly to our crisis. The crusher broke down at the end of February and was returned to us for re-installation in late April. It worked straight away and will operate until a permanent replacement is supplied."