Reliability analysis of rotary unions on balanced machines

Material handling equipment like stackers, reclaimers and ship loaders are grouped as `balanced machines'. These equipment need a continuous water supply, which is provided through a hose, at the end of which there is a 'rotary union' fitting, containing an interface between stationary and rotating parts, which is used to connect the hose to the distribution piping on the equipment. Frequent failures of the rotary unions across the various plants of Rio Tinto Iron Ore operations in the Pilbara, prompted a review of the maintenance strategy for these fittings. A study was done to collect the failure data of the rotary unions on all balanced machines across all plants, followed by a reliability analysis. Machine downtime data was extracted to study the impact of downtime to operations. Costs working for various maintenance strategy scenarios were performed to arrive at the optimum maintenance strategy for the rotary unions.