Imerys Minerals - rotary kiln tyre regrinding
To eliminate the risk of a cracked casing on one of its china clay drying kilns Imerys Minerals, formerly EnglishChina Clays, called upon Metalock Engineering to in-situ machine one of the tyres on a 41 year old kiln toremove the effects of wear. Vibration caused by tyre wear can result in cracks in the hot metal shell of a kiln andalso the internal refractory lining can become detached and break away to contaminate the product.
Kilns used for china clay drying operate at 1080ºC at the hot end down to 600ºC and revolve on circumferentialtyres running on support rollers. A typical 15-metre long drying kiln used by Imerys has two tyres and the kilnis rotated by a rack and pinion system. Tyres tend to wear unevenly as moisture removal while the china clayprogresses down the kiln reduces the weight supported by the rollers. The tyre in question had reached a stagewhere it could no longer be tolerated due to the degree of vibration it was causing. Using the internet, the Imerysengineer in charge investigated companies that had the capability he was seeking and decided to consult withMetalock Engineering as being the most suitable for the job in hand.
Metalock Engineering who has vast experience of kiln tyre grinding undertook to regrind the most badly worn300-mm wide 4-metre diameter steel tyre. The kiln needed to be stationary while Metalock to set up its purpose-designed equipment but as the tyre needed to be revolved to grind it normal production was resumed, thusreducing downtime to a minimum. Normally, a kiln will run continuously 24 hours a day all year round.
Although Metalock had originally planned to restore only one tyre at St Austell, such was the success that it wasasked to repeat the operation on a second identical tyre on the same kiln whilst they were on the premises.Metalock was on site for five days for the set-up and dismantling and the regrinding of two tyres to clean up andrestore roundness. During three of those days, production continued as normal.
Metalock Engineering has been serving industry with mechanical repairs for nearly 60 years and in that time hasaccumulated a wealth of experience in the art of in-situ machining. The technology saves money by eliminatingthe need to dismantle and uproot machinery for transportation to a workshop for repair. Instead, Metalockmoves in to carry out the work on site thus ensuring that costly machinery downtime is minimised.
Metalock Engineering in-situ machined two 4-metre diameter, 300mm wide china clay drying kilntyres for Imerys Minerals to eliminate vibrationcaused by severe tyre wear.