A power station based on the coast of England, draws water from the plentiful supply of sea water that surrounds half of its perimeter. Unfortunately the tidal flow also brings some unwelcome debris, for example sea weed, branches, and rags. Therefore to trap this unwanted debris, the sea water passes through a filter gate.
To clear the filter then requires the gate to be raised and the filter cleaned. The gate is lifted by a large chain drive system. However, the debris can sometimes be so obstructive and dense that the gate gets jammed on its upward travel. The weakest link(pardon the pun) in the drive system is the chain, which snaps when the gate gets jammed, causing damage to the drive cover and requiring expense and downtime to repair.
After a visit by an Autogard engineer, the power station was advised to fit a 406 torque limiter between the drive motor and the input shaft of the first gearbox in the drive train. The 406 is a torque limiter with an elastomeric Samiflex coupling hub fitted. The first time after fitting the torque limiter that the gate was raised, a jam occurred on the gate’s upward travel. The torque limiter immediately dis-engaged, preventing the drive operating. Operators were then able to clear the obstruction to the gate and reset the drive, preventing any damage and saving hours of downtime and the cost of replacing the chain.