Emergency blowout preventer (BOP) closing system

Claim 1

In a control system for blowout preventers used in well operations including a blowout preventer having at least one opening pressure chamber to which fluid pressure is applied to open said blowout preventer and at least one closing pressure chamber to which fluid pressure is applied to close said blowout preventer, one blowout preventer operating power fluid pressure source and an opening conduit and a first closing conduit connecting said one operating power fluid pressure source to said opening and closing chambers, respectively, the improvement comprising: a drain conduit connected to said opening conduit capable of draining fluid from said opening chamber; a valve arranged on said drain conduit controlling flow of fluids through said drain conduit; a nitrogen gas source of operating power fluid pressure independent of said one power fluid source; a shuttle valve connected to said first closing conduit having two positions, in one position said shuttle valve connecting said one power fluid source to said closing chamber and in another position connecting said other independent power fluid source to said closing chamber, said shuttle valve being arranged in said closing conduit adjacent said closing pressure chamber; and a second closing conduit connecting said independent power fluid source and said shuttle valve, said second closing conduit having arranged therein in sequence from said independent power fluid source to said shuttle valve a pressure regulator, a normally open drain valve, a normally closed valve and a pressure gauge, said pressure regulator and said valves and said drain conduit being located adjacent said independent power fluid source.