Abstract: A fluid control circuit and method of operating equipment such as a blowout preventer having a two-way hydraulic piston and cylinder assembly. The circuit includes various features such as a dual pressure level independently controlled fluid supply, a dedicated secondary fluid supply reserved for supplemental use, a dedicated fluid supply reserved for exclusive use in one operating branch, automatic sensor for applying a reserve fluid supply on a sensed demand, a pressure intensifier for increasing available operating force, and control circuitry for preventing loss of enhanced secondary operating energy into a primary circuit.

Abstract: A hydraulic control circuit and method of operating a blowout preventer having a two-way hydraulic piston and cylinder assembly including an open and close port. An adjustable hydraulic supply is connected to a control valve which is in turn connected to the open and close ports. A pressure booster having an input and an output is connected to the close port and a control circuit is connected to the input of the booster and to the close port for actuating the booster and also blocking flow from the control valve to the closed port when the hydraulic supply increases to a predetermined value.

Abstract: In a hydraulic subsea control system having two separate redundant subsea control pods in which each pod is supplied with a hydraulic power supply line and a plurality of fluid control lines by surface controls. The improvement in means for alternately connecting and disconnecting the fluid control lines to each pod. Coacting quick disconnect couplings having first and second portions are positioned between the surface controls and each of the sets of fluid control lines to each pod. Each coupling portion includes a valve whereby when the first and second portions are engaged the valves permit fluid flow and when they are disengaged shut off fluid flow. First and second junction plates are connected between the surface controls and the connected fluid control lines and a hydraulic cylinder and piston assembly is connected between the first and second plates for alternately connecting and disconnecting the couplings to each pod whereby the two pods are controlled separately, but redundantly.

Abstract: A safety apparatus for preventing the traveling block of a drilling rig from being drawn into the top of the rig and also for preventing the traveling block from falling downwardly below a predetermined bottom position. A high position limiting valve has an air inlet and an air outlet with a valve stem providing communication between the inlet and the outlet when a predetermined amount of cable is spooled onto the drum. A low position limiting valve has an air inlet and an air outlet with a stem yieldably urged at all times into engagement with the cable for actuation and providing communication between the inlet and the outlet when a predetermined amount of cable is spooled off of the drum. An air supply is connected to the inlets of the valve and the outlets of the valves supply air to stop the actuation of the cable drum. The longitudinal axis of the valves are positioned generally perpendicular to the surface of the cable drum and their stems are longitudinally movable.

Abstract: A method and apparatus of compensating for the closing force on a blowout preventer caused by well pressure for reducing the wear on the blowout preventer sealing element when moving a drill string through a closed blowout preventer. A hydraulic opening force is applied to the blowout preventer which is actuated by and is proportional to the well pressure. A compensating line is connected between the blowout preventer fluid supply line and the blowout preventer opening line. A control valve is provided in the compensating lines for applying an opening force on the blowout preventer and a pilot control pressure regulator is provided in the compensating line for limiting the compensating pressure. The pilot control line is connected between the regulator and the well pressure in the blowout preventer whereby the output pressure is proportional to the well pressure for compensating for the closing force on the blowout preventer caused by the well pressure.

Abstract: An underwater fluid connector for interconnecting a plurality of fluid lines. A first male member or plurality of members are adapted to be positioned underwater including at least one upright position flat side with a plurality of fluid passageways terminating at said side. An inverted U-shaped retrievable female member having first and second flat interior faces and adapted to engage and disengage from the first member wherein the faces are positioned for alignment with but spaced from the first member flat side when engaged for providing a venting space therebetween and having a plurality of passageways terminating at the interior faces for axial alignment with the first member passageways. A metal valve seat is releasably connected to the first member flat sides about each of the first member passageways. A valve is positioned in each of the second member passageways having a movable element, a hydraulic supply port, and a pilot actuator connected to the valve element.