A single-use pressure-controlled actuator for downhole well tools or mechanisms is provided. The actuator is configured for control of activation/deactivation by agency of wellbore fluid pressure (e.g., pressure levels of drilling fluid or drilling mud in the wellbore). The actuator is further configured for hydraulic actuation by agency of the wellbore fluid. The actuator comprises a plunger displaceably mounted on a sealed cylinder body, with a non-reclosable frangible device closing off wellbore fluid access to an interior of the cylinder body. The frangible device is configured for automatic in response to exposure of wellbore fluid pressures exceeding a predetermined activation threshold. Failure of the frangible device causes exposure of the plunger to the wellbore fluid, resulting in actuated movement of the plunger by hydraulic action of the wellbore fluid.

A fluid pressure control device includes a switching valve configured to operate in conjunction with the control valve by the pilot pressure led through the pilot valve to switch work of the operation check valve. The switching valve includes a pilot chamber to which the pilot pressure is led, a spool that moves in accordance with the pilot pressure of the pilot chamber, a bias member that biases the spool in the valve closing direction, a collar detachably installed in the pilot chamber, and a piston slidably inserted into the collar, the piston being configured to receive the pilot pressure on a back surface thereof and give thrust force to the spool against bias force of the bias member.

The invention relates to a device for controlling and regulating a required pressing force from a current collector of a vehicle on an overhead line, a method for using such a device and a vehicle having at least one such device, wherein the device has a base control circuit, an additional control circuit and a working pressure control circuit. The base control circuit has a base control circuit adjustment device for adjusting a base pressure from a provided power pressure and the additional control circuit has a control device for adjusting an additional pressure from a provided power pressure, wherein the base pressure and the additional pressure act together to form a working pressure and to provide the required pressing force.

A hydraulic system, mining machine and method of controlling a hydraulic actuator. The hydraulic system (HS) is provided with a control valve (23) for controlling movement direction and speed of a hydraulic actuator (HA) connected to the system. Generated force of the hydraulic actuator is controlled independently relative to the control valve by means of counterbalance valves (Cb1, Cb2) and servo valves (Sv1, Sv2) controlling their opening pressure. The counterbalance valves and the servo valves operate as a meter-out control assembly which controls flow of hydraulic fluid discharged from working pressure spaces (16a, 16b) of the hydraulic actuator. The disclosed system may be implemented to control a mining boom (3) of a mining machine (1).

A hydraulic system, mining machine and method of controlling a hydraulic actuator. The hydraulic system (HS) is provided with a control valve (23) for controlling movement direction and speed of a hydraulic actuator (HA) connected to the system. Generated force of the hydraulic actuator is controlled independently relative to the control valve by means of counterbalance valves (Cb1, Cb2) and servo valves (Sv1, Sv2) controlling their opening pressure. The counterbalance valves and the servo valves operate as a meter-out control assembly which controls flow of hydraulic fluid discharged from working pressure spaces (16a, 16b) of the hydraulic actuator. The disclosed system may be implemented to control a mining boom (3) of a mining machine (1).

A downhole tool includes a hydraulically operated actuation device to actuate the downhole tool and a control system that regulates flow of hydraulic fluid to the actuation device. The control system includes a pilot module and a power module. The power module has a first solenoid valve and a second solenoid valve fluidly coupled to a pressure source and a fluid return. The power module is fluidly coupled to the actuation device at an output line and a power line. A first power module check valve is arranged in the power line, a second power module check valve is arranged in a control pressure return line fluidly coupled to the fluid return, a first input communicates with the first solenoid valve, and a second input communicates with the second solenoid valve. A pilot-operated check valve is actuatable in response to a pilot signal to drain hydraulic fluid from the power module.

The invention relates to a device for controlling and regulating a required pressing force from a current collector of a vehicle on an overhead line, a method for using such a device and a vehicle having at least one such device, wherein the device has a base control circuit, an additional control circuit and a working pressure control circuit. The base control circuit has a base control circuit adjustment device for adjusting a base pressure from a provided power pressure and the additional control circuit has a control device for adjusting an additional pressure from a provided power pressure, wherein the base pressure and the additional pressure act together to form a working pressure and to provide the required pressing force.

A hydraulic drive device for an industrial vehicle includes a tank, a hydraulic pump, a capacity control valve, a plurality of hydraulic cylinders, a plurality of direction switching valves, a first hydraulic oil passage, a second hydraulic oil passages, a pilot line, a relief valve, a relief pressure setting portion, a plurality of operation detecting portions, and a control unit. The control valve controls the hydraulic pumps so that a differential pressure between a discharge pressure of the hydraulic pump and a pilot pressure of the pilot line is to be a predetermined pressure. The control unit controls the relief pressure setting portion.

A system for recovering energy from a hydraulic actuator and to a method of operating the system are described. The system may have a hydraulic actuator and a source of hydraulic pressure, comprising a hydraulic pump, in fluid communication with the hydraulic actuator for pressurizing the hydraulic actuator. The system may also have a hydraulic accumulator assembly for selectively absorbing energy from the hydraulic actuator or via the hydraulic actuator. The system may also have a first one-way valve configured to provide fluid communication between the hydraulic actuator and the hydraulic accumulator assembly. The first one-way valve may be configured to permit a flow of fluid through the first one-way valve from the hydraulic actuator to the hydraulic accumulator assembly. The first one-way valve may also be configured to block a flow of fluid through the first one-way valve from the hydraulic accumulator assembly to the hydraulic actuator.

A hydraulic system includes a supply line, at least one implement-based control valve, an implement-based pressure regulating valve, and a load sensing circuit. The implement-based control valve(s) is fluidly coupled to the supply line and configured to regulate a flow of the pressurized hydraulic fluid supplied through at least one downstream actuator line to at least one hydraulic actuator of the implement. The implement-based pressure regulating valve is fluidly coupled to the supply line upstream of the control valve(s) and configured to regulate a fluid pressure to be equal to or greater than a minimum fluid pressure. The load sensing circuit is fluidly coupled to the pressure regulating valve and provides a line or load pressure to the pressure regulating valve. The pressure regulating valve is configured to regulate the supply of the pressurized hydraulic fluid based on the line pressure.