A concrete plant in Ireland had a long running issue with a batch mixer used in their concrete block line. The two paddle mixer shafts were driven by independent geared motors which would fall out of synchronisation and cause the paddles to jam. The mixer shafts were also adversely affected by vibrations, particularly when concrete settled on the mixer blades.

Seeking to upgrade the mixer and resolve these issues, Challenge Ireland were contacted and asked to provide a solution to resolve the issues with the mixers. Working together with experts in industrial motor control and a local specialist gear cutter, a solution was engineered with a controller (a VSD via a SCADA) monitoring and adjusting both motor speeds in the event of lost synchronisation. Two large interlocking gears were used (one on each shaft) as a backup for the motor controller to prevent the mixer blades from coming into contact.

To reduce vibrations and allow easy access for maintenance, Challenge 12022 chain couplings were used as they are capable of handling 17800Nm of torque from each 37kW motor. Complete with a machined 110mm bore and keyway these were manufactured and shipped by Challenge China in little over a month from receiving the order.