ABB drives have cut the need for a manufacturer of specialist chemicals to replace costly gears on its product kiln, saving £18,000 each time.

Thermphos UK is a manufacturer of special chemicals used in applications including pharmaceuticals, hygiene, industrial cleaning, food additives and feed additives. Its products are produced in a rotating kiln, each at its own temperature leading to a wide temperature range experienced by the kiln. At the highest temperatures a 40 mm expansion of the kiln can occur.

The kiln was originally driven by a girth gear around its circumference and thermal expansion meant the gears were threshing, leading to high wear and a need to replace them frequently. To make matters worse the gears were become difficult to source.

Another difficulty was reversing the kiln to remove the product at the end of the process. The increased forces caused by the unloading mechanism threatened to throw the kiln off its supporting trunnion rollers.

Thermphos asked ABB Drives Alliance member Halcyon Drives to design a solution. The power transmission rotating the kiln was updated and redesigned using two motorised gear units driving friction rollers to rotate the kiln drum and controlled by two ABB industrial drives in master/follower control, allowing load sharing.

Using two driven rollers ensures movement due to heat can be tolerated, allowing a wider range of production temperatures. Employing a master/follower arrangement also cuts the need for a feedback encoder, which could be affected by the dusty conditions. Reversing the kiln direction is easier, allowing it to be emptied quicker, increasing productivity.

Mike Organ, works engineer for Thermphos says: “With the new system, we don’t have to worry about gears. We no longer have the major replacement costs and we can run the kiln at any speed we need, using less power.”