Hydraulic system for operating legs of standing offshore platforms - has valve to redirect flow which accelerates lowering and is actuated by impact shock

摘要

The hydraulic system for operating legs of standing offshore platforms has the majority of the jacks serving any one leg connected in parallel, supplied via a pressure actuated diverting valve. Diverted flow goes to a much smaller number of jacks serving the same leg. The system is fed by a constant output pump. The first impact of the leg on the seafloor during lowering produces a pressure wave in the hydraulic system which trips the diverting valve. Restriction of feed to the smaller number of jacks then accelerates the lowering process; respective capacities of system parts are arranged to ensure the leg not leaving the seafloor. Diverted flow back pressure build up re-establishes supply to the other jacks.