A hydraulic control system for blowout preventers systems, frack valves and chokes, and related wellhead and control equipment used in oil and gas well drilling operations. The hydraulic control system can include one or more hydraulic control valves or pressure regulators including an internal, linear slider and pairs of seal rings. Lapped and polished surfaces of the seal rings and sliders can form a dynamic metal-to-metal seal within the hydraulic control valves or pressure regulators.

Various embodiments of the present disclosure provide a rotorcraft-assisted system and method for launching and retrieving a fixed-wing aircraft into and from free flight. The launch and retrieval system includes a modular multicopter, a storage and launch system, an anchor system, a flexible capture member, and an aircraft-landing structure. The multicopter is attachable to the fixed-wing aircraft to facilitate launching the fixed-wing aircraft into free, wing-borne flight. The storage and launch system is usable to store the multicopter (when disassembled) and to act as a launch mount for the fixed-wing aircraft by retaining the fixed-wing aircraft in a desired launch orientation. The anchor system is usable with the multicopter, the flexible capture member, and the aircraft-landing structure to retrieve the fixed-wing aircraft from free, wing-borne flight.

Described herein is a fluid circuit device. The device incorporates at least one pressure balancing valve located between at least two fluid volumes that can be in a pressure differential arrangement wherein the at least one pressure balancing valve acts to address a pressure differential by opening a fluid volume or volumes to a third pressure equalising volume. In use, the fluid circuit device may in one embodiment be used in an energy absorbtion apparatus.

A renewable energy and waste heat harvesting system is disclosed. The system includes an accumulator unit having a high pressure accumulator and a low pressure accumulator. At least one piston is mounted for reciprocation in the high pressure accumulator. The accumulator unit is configured to receive, store, and transfer energy from the hydraulic fluid to the energy storage media. The system collects energy from a renewable energy source and transfers the collected energy using the pressurized hydraulic fluid. The system further includes one or more rotational directional control valves, in which at least one rotational directional control valve is positioned on each side of the accumulator unit. Each rotational directional control valve includes multiple ports. The system also includes one or more variable displacement hydraulic rotational units. At least one variable displacement hydraulic rotational unit is positioned adjacent each of the rotational directional control valves.

An assembly system for components of a pressurized fluid supply system for an agricultural vehicle includes a body having at least one fluid duct connectable at one end to a pressurized fluid supply and having a socket at the other end. A detachable component such as an accumulator or oil filter is connectable in releasable mechanical engagement with the body to receive pressurized fluid from the at least one fluid duct. The engagement results from insertion of at least a portion of the component into the socket and rotation of the component to a locked position. The body has at least one discharge duct extending therethrough. In a partially rotated position of the component portion within the socket, the component remains mechanically attached to the body and the fluid duct and discharge duct are in fluidic connection, discharging accumulated pressure in the fluid duct.

A hydraulic machine. A boom actuator includes a large chamber and a small chamber. A recovery unit receives fluid discharged from the large chamber and then recovers energy. A recovery line connects the large chamber and the recovery unit. An accumulator is connected to a first point on the recovery line. A discharge valve is disposed on the recovery line between the first point and the recovery unit. A first sensor measures a pressure in the accumulator. A controller controls opening and closing of the discharge valve. The controller performs anti-bouncing control of: determining a target pressure in the accumulator corresponding to a load pressure applied to fluid in the large chamber by a load according to a predetermined correspondence; and controlling the opening and closing of the discharge valve such that the pressure in the accumulator measured by the first sensor reaches the target pressure.

A wastegate system of a vehicle includes: a wastegate valve configured to regulate exhaust flow through a turbine of a turbocharger of an engine; a wastegate actuator including a lever that is mechanically coupled to the wastegate valve via one or more linkages and that is configured to move linearly based on a pressure within an interior of the wastegate actuator; a resonator that is fluidly coupled to the interior of the wastegate actuator via a first one or more hoses and that is configured to counteract force attributable to pressure changes in the exhaust from combustion events within the engine; and a regulator valve that is fluidly connected between a pneumatic source and the resonator via a second one or more hoses and that is configured to regulate the pressure within the interior of the wastegate actuator.

Aspects relate to systems and methods for controlling landing gear of an aircraft. An exemplary system includes a nose gear located at a nose of the aircraft, where the nose gear includes a nose piston configured to allow for displacement of a nose wheel relative the aircraft, a main gear located aft of the nose gear, where the main gear includes a main piston configured to allow for displacement of a main wheel relative the aircraft, a hydraulic circuit in fluidic communication with each of the nose piston and the main piston, and a compliant element in fluidic communication with the hydraulic circuit and configured to provide a compliant response at one or both of the nose piston and the main piston.

Aspects relate to systems and methods for controlling landing gear of an aircraft. An exemplary system includes a nose gear located at a nose of the aircraft, where the nose gear includes a nose piston configured to allow for displacement of a nose wheel relative the aircraft, a main gear located aft of the nose gear, where the main gear includes a main piston configured to allow for displacement of a main wheel relative the aircraft, a hydraulic circuit in fluidic communication with each of the nose piston and the main piston, and a compliant element in fluidic communication with the hydraulic circuit and configured to provide a compliant response at one or both of the nose piston and the main piston.

A high-pressure unit (HPU) skid for greasing and actuating a frac tree valve includes one or more hydraulic pumps, a grease pump, a hydraulic reservoir, and two or more accumulators all of which are mounted on a portable frame. The HPU skid further includes fluidic connections to connect the frac tree valve to an output of the grease pump and fluidic connections to connect the frac tree valve to at least one of the two or more accumulators. The hydraulic pumps are configured to withdraw hydraulic fluid from the hydraulic reservoir for charging the accumulators, operating the grease pump, or charging the accumulators and operating the grease pump at a same time.