Abstract: A drive mechanism including a pneumatic cylinder housing, a piston reciprocating in the housing between a first and second dead centers, a pumping shaft driven by the piston, a valve unit, a gas inlet, a gas outlet, the gas inlet is in fluid communication with a first chamber of the cylinder volume, and a second chamber of the cylinder volume in fluid communication with the gas outlet, when the valve unit is in a first state. The gas inlet is in fluid communication with the second chamber of the cylinder volume, and the first chamber of the cylinder volume in fluid communication with the gas outlet, when the valve unit is in a second state. The drive mechanism provides a valve unit actuator having a magnet located adjacent the valve unit and configured to alternately shift the state of the valve unit between the first state and the second state.

Abstract: An engine for actuating a hydraulic downhole pump having a piston vertically reciprocated in a cylinder includes a reversing valve carried with the power piston and serving, when in a first position, to direct fluid flow to force the piston upwardly and in a second position to provide bypass fluid flow to cause the piston to move downwardly. A pilot valve carried by the power piston and serving, when in a lower position, to direct fluid flow to move the reversing valve from the first to the second position. A probe is configured to move the pilot valve to the lower position when the piston reaches an upper limit of travel.

Abstract: A continually operating fluid pressure amplifier having a reciprocating piston system comprising a broad low pressure piston and a narrow high pressure piston, of which the latter, together with its piston cylinder, is arranged as a three-way pilot valve for operating a bistable control valve that controls the reciprocation of the piston system. The control valve has a primary valve slide controlling the said reciprocation and an auxiliary slide operable to open and close relevant conduit connections for initial amplification of the shift control signals governing the operation of the control valve, whereby a very safe operation of the entire system is ensured. Also ensured is a rapid return stroking of the piston system, such that the produced high pressure can be maintained substantially constant.

Abstract: A compressed air pump comprising a compressed air piston motor (11) having a cylinder housing (12) and a low pressure piston (22) moveable between first and second end wall parts (13, 14) and a hydraulic piston pump (15) in the second end wall part (14). One side of the low pressure piston and the first end wall part together define a working chamber (21) and the other side of the piston (22) abuts and drives the hydraulic piston (24). A pilot piston (25), which is controlled by the low pressure piston (22) controls the supply of compressed air to the working chamber (21). A spring powers the return stroke of the low pressure piston and the hydraulic piston. The pilot piston (25) is housed in a pilot cylinder (35) incorporated in the first end wall part (13) and is mounted for movement between a first position and a second position. In the first position compressed air can be passed from an inlet (17) in the end wall part to the working chamber.

Abstract: A hydraulic valve mechanism for a hydraulic motor having a cylinder and a piston reciprocating therein, comprising a valve block having a valve face, a main and an auxiliary central exhaust ports, two main feed ports on opposite sides of the main exhaust port, and two auxiliary feed ports on opposite sides of the auxiliary exhaust port. A valve chest is sealed over the valve face and has aligned piston-receiving bores at its opposite ends, a chamber for pressurized hydraulic fluid between the bores and a valve-actuating piston slideable in the bores. A main D-valve and an auxiliary D-valve operable by the valve-actuating piston move within the chamber in sliding sealing engagement with the valve face. The main D-valve covers and uncovers the main exhaust port and main feed ports to control the reciprocation of the motor piston.

Abstract: A pressure fluid engine of single acting cylinder type has a directional control valve and a master valve with a spool and two valve seats. The spool is formed on a piston rod extending from a piston in the cylinder, the rod passing through a cylindrical disc of the directional control valve. One of the valve seats is provided in the disc to unseal the pilot operating fluid when it cooperates with the spool at a dead point. Another valve seat for the spool is provided in one of the valve chambers of the directional control valve to unseal the pilot operating fluid when it cooperates with the spool at the other dead point. The directional control valve is actuated by means of directional control of a pilot operating fluid with the master valve, in order to reverse the direction of the piston when the piston reaches one of the dead points.