Abstract: A system for energy recovery from a rod pump includes a reversible hydraulic pump; a variable speed reversible motor-generator connected to the reversible hydraulic pump; and a variable speed drive that operates the motor-generator to rotate the reversible hydraulic pump in a forward direction to pump hydraulic fluid to the rod pump during an upstroke, and to operate the motor-generator in a generator mode in which a weight of a rod string lowers a piston in the rod pump during a downstroke to pump hydraulic fluid to rotate the hydraulic pump in reverse such that the motor-generator generates electricity, and the variable speed drive modulates a speed of the motor-generator during the downstroke to modulate a speed of the reversible hydraulic pump to control a rate of flow of hydraulic fluid through the reversible hydraulic pump and thereby modulate a rate of downward motion of the rod string.

Abstract: A system for energy recovery from a rod pump includes a reversible hydraulic pump; a variable speed reversible motor-generator connected to the reversible hydraulic pump; and a variable speed drive that operates the motor-generator to rotate the reversible hydraulic pump in a forward direction to pump hydraulic fluid to the rod pump during an upstroke, and to operate the motor-generator in a generator mode in which a weight of a rod string lowers a piston in the rod pump during a downstroke to pump hydraulic fluid to rotate the hydraulic pump in reverse such that the motor-generator generates electricity, and the variable speed drive modulates a speed of the motor-generator during the downstroke to modulate a speed of the reversible hydraulic pump to control a rate of flow of hydraulic fluid through the reversible hydraulic pump and thereby modulate a rate of downward motion of the rod string.

Abstract: A system includes, in an exemplary embodiment, a hydraulic cylinder having a barrel, a piston connected to a rod string of the rod pump, and a pressure chamber; a reversible hydraulic pump connected to the pressure chamber; and a motor-generator having a rotor shaft connected to a coupling shaft of the pump. The motor-generator operates in a motor mode to rotate the rotor and coupling shafts in a forward direction so that the hydraulic pump pumps hydraulic fluid to the pressure chamber to raise the piston and rod string in an upstroke, and operates in a generator mode in which a weight of the rod string displaces the piston in a downstroke to pump hydraulic fluid from the pressure chamber to rotate the pump coupling shaft and the rotor shaft in a reverse direction such that the motor-generator generates electricity. A variable speed drive modulates the speed of the motor-generator.

Abstract: A drilling rig mobility system moves a drilling rig or similar structure in an oilfield or similar environment and includes independently controllable positioning shoes attaching to the drilling rig and controllable through separate and coordinated position control commands. Each positioning shoe may be individually addressed to reposition the drilling rig. Each positioning shoe includes a hydraulic actuator and wireless control circuitry. The hydraulic actuator provides vertical and horizontal force in response to wireless control signals for wireless position and control data and instructions with a remote wireless communications device. A cylinder stomper vertically elevates the hydraulic actuator and receives and transfers the vertical force. A foot assembly transfers the horizontal force from the hydraulic actuator. A positioning shoe cylinder stomper and positioning shoe traverse cylinder provide infinitely variable position control. Rotational positioning may be manually or automatically achieved.

Abstract: A drilling rig mobility system moves a drilling rig or similar structure in an oilfield or similar environment and includes independently controllable positioning shoes attaching to the drilling rig and controllable through separate and coordinated position control commands. Each positioning shoe may be individually addressed to reposition the drilling rig. Each positioning shoe includes a hydraulic actuator and wireless control circuitry. The hydraulic actuator provides vertical, horizontal and rotational force in response to wireless control signals for wireless position and control data and instructions with a remote wireless communications device. A cylinder stomper vertically elevates the hydraulic actuator and receives and transfers the vertical and rotational force. A foot assembly transfers the horizontal force from the hydraulic actuator. A positioning shoe cylinder stomper and positioning shoe traverse cylinder provide infinitely variable position control.

Abstract: A system for energy recovery from a rod pump includes, in an exemplary embodiment, a hydraulic cylinder having a barrel, a piston, and a pressure chamber; the piston connected to a rod string of the rod pump; a reversible hydraulic pump connected to the pressure chamber; and a motor-generator having a rotor shaft connected to a coupling shaft of the pump; wherein the motor-generator operates in a motor mode to rotate the rotor and coupling shafts in a forward direction so that the hydraulic pump pumps hydraulic fluid to the pressure chamber to raise the piston and rod string in an upstroke, and operates in a generator mode in which a weight of the rod string displaces the piston in a downstroke to pump hydraulic fluid from the pressure chamber to rotate the pump coupling shaft and the rotor shaft in a reverse direction such that the motor-generator generates electricity.

Abstract: Apparatus and methods move a rod via a solenoid. A solenoid moves an armature and compresses a spring when the solenoid is energized. The armature moves in response to the energization of the solenoid and couples with the rod, which transfers motion to a working portion. A stroke limiter limits movement of the first armature within the first solenoid when the solenoid is energized. The stroke limiter comprises a surface with a first portion limiting the movement of the armature, a second portion adjustably coupling the stroke limiter to the solenoid thereby setting a stroke length, the second portion releasably coupling the stroke limiter to a fastener, a third portion allowing for adjustment of the position of the stroke limiter and being shaped to fit an adjusting member. The fastener secures the stroke limiter in place with respect to the solenoid and maintaining the stroke length.

Abstract: In various embodiments, pneumatic cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the pneumatic cylinder assemblies during expansion or compression of a gas.