Abstract: A motor driven hydraulic lift pump assembly for oil wells includes a mechanical flywheel connected to a hydraulic pump/motor combination in turn incorporated in the hydraulic circuit of the well lift cylinder. The pump/motor and flywheel assembly with associated hydraulic control can be separately mounted on a skid and connected into the hydraulic and electrical circuitry for the well lift cylinder. The combination pump/motor reverses in mode as the vertically mounted well cylinder piston moves upwardly and downwardly to pump from a deep well. As the well cylinder piston moves downwardly the pump/motor is in motor mode storing energy by increasing the rotational speed of the flywheel. As the well cylinder piston moves upwardly the pump/motor is in the pump mode and energy is taken from the flywheel to assist in raising the well cylinder piston to pump crude oil from the deep well.

Abstract: A hydraulic pile driving hammer system is described which requires only a single pressure operated pilot to obtain switching for reversal of hydraulic forces at both ends of its stroke.

Abstract: A novel emergency flow shut off device for fluid control systems particularly adapted for use in adverse marine environments. In normal operation the valve spool is continuously exercised by a reversing fluid pressure differential as fluid reversibly flows through the valve. External means are provided to conveniently monitor movement of the spool and thereby assure that the spool is free to shut off flow in a sudden emergency. Fluid cushioning means are provided at the end of the spool emergency shut off stroke to prevent damage to the valve. In a typical application the vertical motion of an offshore drill ship on the ocean swells causes oscillating flow in the fluid control system thereby automatically exercising the valve.

Abstract: An improved exerciseable emergency flow shut off device for fluid control systems particularly adapted for use in adverse marine environments. In normal operation the valve spool is continuously exercised by a reversing fluid pressure differential as fluid reversibly flow through the valve. The improved valve includes low breakaway force spool biasing means to reduce the internal fluid resistance of the valve in normal operation and high breakaway force restraining means connected to the shut off means. In the preferred embodiment the spool biasing means and restraining means comprise separate coil springs concentrically located on the spool, the biasing means having a spring rate substantially lower than the restraining means. The biasing coil is reciprocateably compressed in response to the reversing fluid pressure differentials thus minimizing flow resistance. The restraining means is compressed in response to a sudden excess pressure differential thereby permitting shut off of the valve.