Thermal energy recovery systems include a piston assembly including a primary cylinder adapted to receive vapor; first and second secondary cylinders extending from opposite ends of the primary cylinder; a primary piston disposed for displacement in the primary cylinder; first and second secondary pistons disposed for displacement in the first and second secondary cylinders, respectively; and a piston connecting member connecting the first and second secondary pistons to the primary piston.

Systems are provided comprising at least one driving cylinder comprising a driving chamber and a driving piston within the driving chamber. The driving piston separates the driving chamber into a driving fluid zone for receiving a driving fluid and a buffer zone for receiving a buffer fluid. The driving piston is movable in the driving chamber by the driving fluid. The systems may also comprise a driven cylinder comprising a driven chamber and a driven piston moveable in the driven chamber. The driven piston is connected to and driven by the driving piston to move within the driven chamber. The driven chamber comprises an input port configured to receive a driven fluid at a first, lower pressure into the driven chamber and an output port configured to expel the driven fluid at a second, higher pressure from the driven chamber when the driven fluid is pressurized by the driven piston. The buffer fluid is different from the driving fluid and the driven fluid, and the buffer fluid in the buffer zone separates the driving fluid from the driven fluid.

Systems are provided comprising at least one driving cylinder comprising a driving chamber and a driving piston within the driving chamber. The driving piston separates the driving chamber into a driving fluid zone for receiving a driving fluid and a buffer zone for receiving a buffer fluid. The driving piston is movable in the driving chamber by the driving fluid. The systems may also comprise a driven cylinder comprising a driven chamber and a driven piston moveable in the driven chamber. The driven piston is connected to and driven by the driving piston to move within the driven chamber. The driven chamber comprises an input port configured to receive a driven fluid at a first, lower pressure into the driven chamber and an output port configured to expel the driven fluid at a second, higher pressure from the driven chamber when the driven fluid is pressurized by the driven piston. The buffer fluid is different from the driving fluid and the driven fluid, and the buffer fluid in the buffer zone separates the driving fluid from the driven fluid.

Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

A method of producing fluid from a wellbore includes operating a pump located proximate to a zone of fluid influx in the wellbore to draw a fluid from a reservoir into the wellbore at the zone of fluid influx. A first section of a tubing string is coupled to, and extends above, the pump, and a second section of the tubing string is coupled to, and extends below, the pump. A packer seals a first annular space around the first section of the tubing string. The method further includes operating the pump to move the fluid from the second section of the tubing string and into the first section of the tubing string.

A switching device for alternately connecting a hydraulic drive of a lubricating pump to a pressure line and to a return line of a hydraulic circuit. The switching device includes first and second drive lines connected to the hydraulic drive, and pressure and return drive lines connected to the pressure and return lines. A switching valve is in fluid communication with the drive lines and is switchable between first and second switching states to connect the pressure drive line to the first drive line or to the second drive line. A plurality of hydraulic control lines control the position of the switching valve. The drive lines are configured to conduct a first volumetric flow of hydraulic fluid and the hydraulic control lines are configured to conduct a second volumetric flow of the hydraulic fluid different than the first volumetric flow.

A pumpable resin system for installation of mine bolts includes a resin injection cylinder comprising a resin chamber and a resin hydraulic cylinder, a catalyst injection cylinder including a catalyst chamber and a catalyst hydraulic cylinder, with the resin hydraulic cylinder synchronized with the catalyst hydraulic cylinder, a hydraulic pump in fluid communication with the resin hydraulic cylinder and the catalyst hydraulic cylinder, a hydraulic reservoir in fluid communication with the hydraulic pump, and a delivery line in fluid communication with the resin injection cylinder and the catalyst injection cylinder. The delivery line is configured to deliver resin and catalyst from the resin injection cylinder and catalyst injection cylinder into a borehole.

A pumpable resin system for installation of mine bolts includes a resin injection cylinder comprising a resin chamber and a resin hydraulic cylinder, a catalyst injection cylinder including a catalyst chamber and a catalyst hydraulic cylinder, with the resin hydraulic cylinder synchronized with the catalyst hydraulic cylinder, a hydraulic pump in fluid communication with the resin hydraulic cylinder and the catalyst hydraulic cylinder, a hydraulic reservoir in fluid communication with the hydraulic pump, and a delivery line in fluid communication with the resin injection cylinder and the catalyst injection cylinder. The delivery line is configured to deliver resin and catalyst from the resin injection cylinder and catalyst injection cylinder into a borehole.

A double-acting pump device includes a piston arrangement being slidably arranged in a pump housing. The pump housing is separated into a drive section with a drive fluid inlet and a drive fluid outlet and a pump section with an inlet and an outlet for a pump fluid. The drive section includes a switch mechanism which utilizes the difference between the drive fluid supply pressure and the drive fluid outlet pressure to reciprocate the piston arrangement, such that axially acting forces are transferred to the pump fluid which thereby achieves a desired pressure increase. Thus, the double-acting pump is arranged to utilize the energy in a supplied drive fluid to provide a defined pressure increase in a supplied pump fluid.