A counter pressure valve arrangement for controlling a pressure level of a hydraulic fluid in a return line from a hydraulic actuator arrangement. The counter pressure valve arrangement comprises a counter pressure valve having: a moveable valve member; a counter pressure regulating port configured for being connected to the hydraulic actuator arrangement via the return line; a tank port configured for being connected to a tank or low pressure reservoir for storing low pressure hydraulic fluid; and a pump port configured for being connected to a source of pressurised hydraulic fluid. A first position of the valve member effects fluid communication between the pump port and the counter pressure regulating port for supplying pressurised hydraulic fluid to the return line, and a second position of the valve member effects fluid communication between the counter pressure regulating port and the tank port for discharging hydraulic fluid from the return line to the tank.

A control system for controlling the down pressure applied to a soil-engaging component of an agricultural implement includes a down pressure actuator coupled to the soil-engaging component, and an energy storage device and a piston-containing cylinder are coupled to each other by a system containing pressurized fluid. A check valve is coupled between the energy storage device and the down pressure actuator to control the flow of the pressurized fluid from the energy storage device to the cylinder. A controllable relief valve and variable orifice are coupled between the down pressure actuator and the energy storage device to control the flow of the pressurized fluid from the cylinder to the energy storage device. A controller supplies control signals to the relief valve and variable orifice to control the flow of the pressurized fluid from the cylinder to the energy storage device based on the pressure of the pressurized fluid.

A valve control system and a valve control method can improve working efficiency and security of the operator. The valve control system includes: a regulating valve, mounted to a pipeline to control the opening or closing of the pipeline; an driving device, connected to the regulating valve and configured to control the regulation of the regulating valve; a detector, mounted to the pipeline and configured to detect fluid pressure in the pipeline; a first controller, connected to the driving device and the detector and configured to control the driving device; and a second controller which can perform data interaction with the first controller, wherein the first controller can perform corresponding regulation according to an instruction from the second controller.

Systems and methods for calibration of an electrohydraulic control valve are provided. In one aspect, a method for calibrating an electrohydraulic control valve includes providing fluid communication between the pump and the reservoir through a bypass calibration orifice. The bypass calibration orifice defines a known restriction. The method further includes measuring a pressure drop across the bypass calibration orifice, commanding the electrohydraulic control valve, calculating a pressure drop across the electrohydraulic control valve, recording the command applied to the electrohydraulic control valve corresponding with the calculated pressure drop across the electrohydraulic control valve, and calibrating the electrohydraulic control valve based on at least two of the recorded command, the known restriction, the measured pressure drop across the bypass calibration orifice, and the calculated pressure drop across the electrohydraulic control valve.

A hydraulic control device with a pressure control valve that has a control piston and a modulating piston which can move relative to one another. The control piston and the modulating piston are pushed apart from one another by at least one spring. At one end face of the modulating piston there is arranged a pressure chamber in such a manner that when the pressure chamber is filled, the modulating piston is caused to move in the direction toward the control piston. The pressure chamber can be filled by a first volume flow Q1 of a pressure medium. A venting line, with at least one further throttle, is connected to the pressure chamber. A second volume flow Q2 can be discharged, via the venting line, from the pressure chamber. The hydraulic control device can be utilized in a marine transmission.

The present invention is a fluid distribution system comprising connected conduits (e.g., lines) wherein fluid flows, such as pipes within a building. The lines may be configured to: (i) include multiple lines that connect at intersections (some of the intersections will be identified as nodes); and (ii) incorporate node units associated with line pressure loss simulation assemblies (“LLSAs”). Activities of a node unit incorporating a LLSA can result in alterations in fluid pressure, such as by a loop control process to reposition balancing valves or other valves of one or more LLSAs, and/or by alteration of the speed of the system pump. These activities adjust fluid pressure to cause the system to produce a balanced and high efficiency energy transfer (e.g., heating or cooling), and do not involve or require any identification or use of any specific, fixed or absolute pressure value. They function based on an operation locus (for a node unit) and/or an operation locus range (for node unit groupings) to adjust the fluid pressure.

A pressure control device has at least two switching valves (10, 12), a feedback control unit (14), a sensor unit (20), and a voltage supply unit (24), and continuously adjusts hydraulic systems.

A method is described for controlling pneumatic pressure by actuating a charge and a discharge valve that vary the pressure, comprising, among other things, providing a matrix wherein each cell indicates a time for opening the charge or discharge valve; if the initial pressure value (PVi) in the volume is less than the target pressure value (PVt) to be reached, opening the charge valve, decreasing the value of the opening time indicated in the selected cell if the pressure value in the volume exceeds the target pressure value (PVt) and possibly increasing the value of the time indicated in the selected cell; if the initial pressure value (PVi) in the volume is greater than the target pressure value (PVt), opening the one discharge valve for the time indicated in a selected cell and possibly increasing the time value indicated in the selected cell and possibly decreasing the time value indicated in the selected cell.

A method for controlling conditions within a liquid conduit system. The method comprising: defining a zone within the liquid conduit system, wherein pressure within the zone is influenced by one or more actuator valves; controlling the one or more actuator valves in dependence on a Pareto efficient solution to the minimisation of functions of the average pressure within the zone (AZP) and the pressure variability within the zone (PVZ).

A method of mixing at N gases is provided. This method includes providing N gas flow meters, including N gas flows, wherein N is 3 or more. Measuring each of the N gas flows, at first predetermined intervals of time, and totaling each of the measured N flows over a second predetermined interval of time. Adding the N measured gas flows, thereby determining the total gas flow at the second predetermined interval of time. Dividing the total gas flow for each of the N gas flows by the total gas flow, thereby determining a cumulative calculated theoretical percentage for each of the N gas flows over the second predetermined interval of time. And sounding an alarm, and/or terminating the N gas flows, if the cumulative calculated theoretical percentage for any of the N gas flows exceeds a predetermined range value.