A lifting control device includes: a position acquisition portion configured to acquire an extended or contracted position of the hydraulic cylinder; a target setting portion configured to set a target position of the hydraulic cylinder; a control portion configured to control an energized amount of the solenoid valve; and an input judging portion configured to judge whether the operational input is an opening command to perform an opening control in which the solenoid valve is made to be fully open or is a positional control command to perform a positional control in which the solenoid valve is actuated according to an operation input amount to control the extended or contracted position of the hydraulic cylinder, wherein when the operational input is judged as the opening command by the input judging portion, the opening control is performed due to the non-integral type control by the control portion.

A spool valve includes a valve portion that opens and closes a portion between an input port and an output port and a radial-direction-position changing portion provided in an outer lateral surface of the valve portion in a radial direction. When a first value is equivalent to or larger than a threshold that is larger than 0, the portion between the input port and the output port are opened to permit a flow of the oil inside the first connection oil passage, and when the first value is smaller than the threshold, the portion is closed to block the flow of the oil inside the first connection oil passage. The radial-direction-position changing portion extends in the axial direction, and a position thereof in the radial direction changes inwardly from a first side towards a second side in the axial direction.

A pressure multiplier having a cylinder assembly, a command device, and an electronic control unit is provided. The electronic control unit is configured to obtain a switching signal to be provided to the command device from a compression curve which, knowing pressure of a fluid entering the pressure multiplier, binds a pressure increase of the fluid exiting the pressure multiplier with a switching frequency of a piston of the cylinder assembly.

A manifold system 100 with 2oo3 configuration is disclosed having three solenoid valves 102 and two shuttle valves 108 operatively coupled to the three solenoid valves 102. The manifold system 100 includes an external pilot operated logic control valve 116 operatively coupled to the two of the three solenoid valves 102 and to at least one of the shuttle valves 108 to provide 2oo3 configuration.

Universal control circuitry for an electro-hydraulic valve actuator system includes logic gate circuitry to control one or more of a closing solenoid valve, an opening solenoid valve, an emergency shutdown solenoid valve, and a hydraulic fluid pump motor to route hydraulic fluid through a hydraulic circuit to actuate a valve via a hydraulic actuator according to received commands. The universal control circuitry is configured to control operation for multiple different configurations of a hydraulic valve actuator system including double-acting configurations, single-acting spring-to-open configurations, and single-acting spring-to-close configurations, each with or without an emergency shutdown arrangement (which may be configured to trip based on an external shutdown input alone or in combination with a local system power failure), a hydraulic accumulator, and maintained or momentary input commands.

An intermittent air discharge apparatus has a main valve and a pilot valve, the main valve being switched between a discharge state and a discharge stop state. The pilot valve is switched between an air-supply state to supply air to a pilot chamber for air-discharge, and an air-supply stop state. When the pilot valve is switched to the air-supply state, an exhaust passage communicates with the pilot chamber for air-discharge. When the pilot valve is switched to the air-supply state, a supply or exhaust passage allows an air supply passage to communicate with the pilot chamber for air-discharge and a pilot chamber for stopping air-supply; when the pilot valve is switched to the air-supply stop state, communication with the air supply passage is blocked. A flow rate of air from the pilot chamber for air-discharge is set by the exhaust passage, and a flow rate of air from the pilot chamber for stopping air-supply is set by the supply or exhaust passage.

A method of controlling a plurality of downhole tools in a wellbore, using first and second codes transmitted by hydraulic line to first address and then actuate the desired tool. A dedicated line is provided for terminating all actuated tools.

Universal control circuitry for an electro-hydraulic valve actuator system includes logic gate circuitry to control one or more of a closing solenoid valve, an opening solenoid valve, an emergency shutdown solenoid valve, and a hydraulic fluid pump motor to route hydraulic fluid through a hydraulic circuit to actuate a valve via a hydraulic actuator according to received commands. The universal control circuitry is configured to control operation for multiple different configurations of a hydraulic valve actuator system including double-acting configurations, single-acting spring-to-open configurations, and single-acting spring-to-close configurations, each with or without an emergency shutdown arrangement (which may be configured to trip based on an external shutdown input alone or in combination with a local system power failure), a hydraulic accumulator, and maintained or momentary input commands.

A method for determining an operating force (F.sub.p) of a positioning actuator (3), whose adjustment movements are produced by virtue of an appropriate supply of a working medium via actuating at least one valve (4 to 7) associated with the positioning actuator (3). The operating force (F.sub.p) is determined by computational determination. To be able to carry out the computational determination of the operating force (F.sub.p) with little effort, by the at least one valve (4 to 7) in each case, a respective, essentially constant mass flow ({dot over (m)}.sub.iv, {dot over (m)}.sub.ov) of working medium is maintained either into the positioning actuator (3) and/or out of the positioning actuator (3).

An actuator according to the present invention includes a cylinder, a piston inserted into the cylinder to be free to slide, a rod that is inserted into the cylinder and connected to the piston, a rod side chamber and a piston side chamber defined by the piston within the cylinder, a tank, a first opening/closing valve provided in a first passage that connects the rod side chamber to the piston side chamber, a second opening/closing valve provided in a second passage that connects the piston side chamber to the tank, a pump that supplies a working fluid to the rod side chamber, a motor that drives the pump, an exhaust passage that connects the rod side chamber to the tank, and a passive valve that is provided in the exhaust passage and has a predetermined pressure/flow rate characteristic.