A pump includes a liquid housing having a liquid chamber with a piston/diaphragm assembly arranged therein that responds to a suction stroke and draws liquid into the liquid chamber, and responds to a pressure stroke and provides liquid from the liquid chamber; and a gas housing having a slide valve assembly separating first and second gas chambers. The slide valve assembly responds to a suction-to-pressure-force at the suction stroke conclusion, changes from a suction-to-pressure stroke state, provides gas from the first to second gas chamber through the slide valve assembly, and provides the pressure stroke so liquid passes from the liquid chamber; and responds to a pressure-to-suction-force at the pressure stroke conclusion, changes from the pressure-to-suction stroke state, provides gas from the second chamber through the slide valve assembly, and provides the suction stroke so liquid is drawn into the liquid chamber.

A pump includes a liquid housing having a liquid chamber with a piston/diaphragm assembly arranged therein that responds to a suction stroke and draws liquid into the liquid chamber, and responds to a pressure stroke and provides liquid from the liquid chamber; and a gas housing having a slide valve assembly separating first and second gas chambers. The slide valve assembly responds to a suction-to-pressure-force at the suction stroke conclusion, changes from a suction-to-pressure stroke state, provides gas from the first to second gas chamber through the slide valve assembly, and provides the pressure stroke so liquid passes from the liquid chamber; and responds to a pressure-to-suction-force at the pressure stroke conclusion, changes from the pressure-to-suction stroke state, provides gas from the second chamber through the slide valve assembly, and provides the suction stroke so liquid is drawn into the liquid chamber.

A pump assembly. The pump assembly may comprise a motor portion for driving a fluid pumping portion via a piston. The motor portion may comprise: a spool and a spool housing assembly having a spool chamber. The spool may be disposed within the spool chamber. The spool may comprise an upper portion and a lower portion, wherein the diameter of the lower portion is larger than the diameter of the upper portion. The spool may also comprise: (1) two support groove portions for cradling two slide valves and (2) two spool bores, which are in fluid communication with the two slide valves. The piston of the pump assembly may comprise a valve stem having a valve stem bore and valve stem openings. The valve stem openings may be funnel-shaped or may inwardly slope into the valve stem bore to prevent or minimize cutting or shredding of a blown seal.

A pump assembly. The pump assembly may comprise a motor portion for driving a fluid pumping portion via a piston. The motor portion may comprise: a spool and a spool housing assembly having a spool chamber. The spool may be disposed within the spool chamber. The spool may comprise an upper portion and a lower portion, wherein the diameter of the lower portion is larger than the diameter of the upper portion. The spool may also comprise: (1) two support groove portions for cradling two slide valves and (2) two spool bores, which are in fluid communication with the two slide valves. The piston of the pump assembly may comprise a valve stem having a valve stem bore and valve stem openings. The valve stem openings may be funnel-shaped or may inwardly slope into the valve stem bore to prevent or minimize cutting or shredding of a blown seal.

An artificial lift system for use with a subterranean well can include a cylinder having a piston reciprocably disposed therein, the piston having opposing sides, one side being selectively communicable with a hydraulic pressure source and a hydraulic reservoir, and the other side being selectively communicable with the hydraulic pressure source and at least one accumulator, and the accumulator being selectively communicable with an input side of a pump of the hydraulic pressure source. A method of controlling an artificial lift system can include connecting a cylinder to a hydraulic pressure source including a hydraulic pump, the pump being connected between the cylinder and at least one accumulator, the accumulator being connected to a gas pressure source, and operating a gas compressor of the gas pressure source, thereby increasing hydraulic pressure applied to the pump from the accumulator.

An artificial lift system for use with a subterranean well can include a cylinder having a piston reciprocably disposed therein, the piston having opposing sides, one side being selectively communicable with a hydraulic pressure source and a hydraulic reservoir, and the other side being selectively communicable with the hydraulic pressure source and at least one accumulator, and the accumulator being selectively communicable with an input side of a pump of the hydraulic pressure source. A method of controlling an artificial lift system can include connecting a cylinder to a hydraulic pressure source including a hydraulic pump, the pump being connected between the cylinder and at least one accumulator, the accumulator being connected to a gas pressure source, and operating a gas compressor of the gas pressure source, thereby increasing hydraulic pressure applied to the pump from the accumulator.

Hybrid thermodynamic compressor (8) for compressing a working fluid, the compressor comprising a volumetric cylinder (1) and a thermal cylinder (2) connected to one another mechanically by a connecting rod system (5) and pneumatically by a connecting circuit (12) optionally with a valve (4), a reversible electric machine (6), the volumetric cylinder comprising a first piston (81) that separates a first chamber (Ch1) from a second chamber (Ch2), the thermal cylinder comprising a second piston (82) which separates a third chamber (Ch3) from a fourth chamber (Ch4), which can be brought into thermal contact with a heat source (21) to thereby generate a cycled movement in the thermal cylinder, and concerning the connecting rod system (5), the first and second pistons are connected to a rotor (52) by first and second respective connecting rods (91,92), with a predetermined angular offset (θd), the volumetric cylinder being equipped with non-return valves (61,62), the power produced in the thermal cylinder being transmitted to the volumetric cylinder essentially via the connecting circuit and not via the rod system.

An apparatus may include a reservoir; a stopper dividing the reservoir; a water fill pipe configured to provide the water to a lower portion of the reservoir; and an outlet pipe connected to the lower portion of the reservoir. The apparatus may further include a compressed air feed pipe which may provide compressed air to an upper portion of the reservoir to press on the stopper so that the water is forced by the stopper to escape from the lower portion of the reservoir through the outlet pipe. A processor included in the apparatus may be configured to determine a water pumping rate of the water while the water escapes through the outlet pipe, and to control the compressed air feed pipe to provide the compressed air at an air pumping rate equal to the water pumping rate.

An apparatus may include a reservoir; a stopper dividing the reservoir; a water fill pipe configured to provide the water to a lower portion of the reservoir; and an outlet pipe connected to the lower portion of the reservoir. The apparatus may further include a compressed air feed pipe which may provide compressed air to an upper portion of the reservoir to press on the stopper so that the water is forced by the stopper to escape from the lower portion of the reservoir through the outlet pipe. A processor included in the apparatus may be configured to determine a water pumping rate of the water while the water escapes through the outlet pipe, and to control the compressed air feed pipe to provide the compressed air at an air pumping rate equal to the water pumping rate.

A pump includes a liquid housing having a liquid chamber with a piston/diaphragm assembly arranged therein that responds to a suction stroke and draws liquid into the liquid chamber, and responds to a pressure stroke and provides liquid from the liquid chamber; and a gas housing having a slide valve assembly separating first and second gas chambers. The slide valve assembly responds to a suction-to-pressure-force at the suction stroke conclusion, changes from a suction-to-pressure stroke state, provides gas from the first to second gas chamber through the slide valve assembly, and provides the pressure stroke so liquid passes from the liquid chamber; and responds to a pressure-to-suction-force at the pressure stroke conclusion, changes from the pressure-to-suction stroke state, provides gas from the second chamber through the slide valve assembly, and provides the suction stroke so liquid is drawn into the liquid chamber.