Ball bearings double uptime of tyre shredding machines

Sapphire Energy Recovery operates

high-throughput shredding machines in four major conurbations throughout the UKproviding a sustainable solution for end-of-life car and van tyres by processing them into chips. These are used as an alternative to coal in cement manufacture.

After shreddingthe tyre chips are graded for size by a classifier with 36 sets of bearings. The classifier shafts’ set-screw style bearings were being damagedby both the fine metal wires in the tyresand the water used for cooling. As a result they had a lifetypicallyof less than six months.

Changing the classifier bearings could then take anything up to two hours/bearingdepending on the problems encountered and the skill of the operators. Corrosion sometimes meant that the bearings needed to be loosened by heatfor exampleand in some cases the whole shaft had to be replaced.

Sapphire is the UK’s leading end of life car and van tyre processorand its processing centres often operate for 24hours a day. Addressing the planned and emergency maintenance requirements of these machines became a priority for Sapphire’s Reliability Manager Andy Boothand he called in the specialist Dodge distributorBearing Transmission & Pneumaticsto discuss the problem.

Bearing Transmission & Pneumatics suggested that Sapphire try a type of ball bearing from Baldor’s range called the Dodge Grip Tight. This adapter-style bearing has a mechanical maintenance feature that loosens it by simply turning a nut. The action automatically pulls the bearing offavoiding any need for forcible removal or expansion heating – eliminating fretting corrosion and preventing shaft damage.

The bearings were a little more expensive more than the set screw type that Sapphire had been usingbut demonstrations – and examples of field experience in the most hostile conditions – convinced Andy Booth that the ‘easy-off’ mechanism would make changeovers a predictable operation.

Sapphire purchased some Grip Tights and installed them as and when the previous bearings failed. Although predictable maintenance was Booth’s major requirementit became obvious the bearings offered a superior life tooas the life period came and went. Grip Tight’s built-in flinger seal is protecting the bearings in the hostile environment to such as an extent that they are lasting typically twice as long as the previous set screw types.

With Grip Tight changeovers are predictable and take only 15minutes maximum.