A hydraulic system including: a pressure line; a pump; an actuator; a valve device configured to control the flow of pressurized hydraulic fluid to the actuator; an electronic control unit configured to control the valve device by a control signal proportional to the desired speed of the actuator at any given time; a pressure accumulator capable of supplying, together with the pump, pressurized hydraulic fluid for moving the actuator; a sensor device configured to measure, directly or indirectly, the amount of pressurized hydraulic fluid in the pressure accumulator at any given time; setting devices configured to set a setting signal to be proportional with the desired speed of the actuator at any given time. The electronic control unit is configured to restrict the targeted speed of the actuator not to exceed a predetermined maximum speed which is proportional to the amount of pressurized hydraulic fluid in the pressure accumulator.

A hydropneumatic piston accumulator has an accumulator housing (1) defining a housing longitudinal axis (11) and a piston (9) longitudinally movable between two housing covers (5, 7) positioned opposite each other. In the housing (1), the piston (9) separates a working chamber (13) for a compressible medium, such as a working gas, from a working chamber (15) for an incompressible medium, such as hydraulic fluid. A piston part (55) of a displacement measurement device continuously determines each position of the piston (9) in the housing (1). A rod-shaped guide (29, 57) is stationarily positioned in the accumulator housing (1) and passes all the way through the piston (9) in each of its displacement positions in the accumulator housing (1). The piston (9) is movably guided along the guide until it reaches the stop on one of the two housing covers (5, 7) and is sealed against this guide (29,57) using a sealing device (49, 50).

A pressure vessel arrangement includes a pressure vessel and an optical sensor arrangement. The pressure vessel includes: a cylinder construction having a cylinder wall extending from a cylinder wall first end to a cylinder wall second end, and having an internal surface forming an interior region; a first end cap closing the cylinder wall first end and having an optical window located therein to permit passage of light therethough and into the interior region; a second end cap closing the cylinder wall second end; and a piston constructed to slide within the cylinder construction interior region along a direction between the cylinder all first end and the cylinder wall second end and along the cylinder construction internal surface to separate the interior region into a first end interior region and a second end interior region. The pressure vessel is constructed to withstand a fatigue test of one million cycles at 5,000 psi without failure. The optical sensor arrangement is located outside of the optical window and includes an emitter for emitting light through the optical window and into the interior region and receiving for receiving light reflected from the piston. Also included is a method for providing a piston position feedback in a pressure vessel.

A hydropneumatic piston accumulator, with an accumulator housing (1) defining a housing longitudinal axis (11), in which a piston (9) is longitudinally movable between two housing covers (5, 7) positioned opposite each other. In the housing (1), the piston (9) separates a working chamber (13) for a compressible medium, such as a working gas, from a working chamber (15) for an incompressible medium, such as hydraulic fluid, and comprises at least a part (55) of a displacement measurement device continuously determining each position of the piston (9) in the housing (1). The invention is characterised in that a rod-like guide (29, 57) is stationarily positioned in the accumulator housing (1) and passes all the way through the piston (9) in each of its displacement positions in the accumulator housing (1), the piston (9) being movably guided therealong until it reaches the stop on one of the two housing covers (5, 7), and in that the piston (9) is sealed against this guide (29, 57) using a sealing device (49, 50).

A hydraulic system including: a pressure line; a pump; an actuator; a valve device configured to control the flow of pressurized hydraulic fluid to the actuator; an electronic control unit configured to control the valve device by a control signal proportional to the desired speed of the actuator at any given time; a pressure accumulator capable of supplying, together with the pump, pressurized hydraulic fluid for moving the actuator; a sensor device configured to measure, directly or indirectly, the amount of pressurized hydraulic fluid in the pressure accumulator at any given time; setting devices configured to set a setting signal to be proportional with the desired speed of the actuator at any given time. The electronic control unit is configured to restrict the targeted speed of the actuator not to exceed a predetermined maximum speed which is proportional to the amount of pressurized hydraulic fluid in the pressure accumulator.

A hydropneumatic piston accumulator has an accumulator housing (1) with a cylindrical tube (3) defining a longitudinal axis (11). The cylindrical tube (3) is closed at both ends by housing covers (5, 7). A piston (9) is longitudinally movable in the cylindrical tube (3) and separates a working chamber (13) for a compressible medium from a working chamber for an incompressible medium. A displacement measuring device determines the position of the piston (9) in the housing in a contact-free manner. The displacement measuring device includes a non-magnetic measuring tube (29) extending along the longitudinal axis (11) from one housing cover (5) to the other housing cover (7) and through a passage (31) formed in the piston (9) and is sealed against the interior of the housing (1). In the tube (29), a position sensor (57) is movably guided and follows the piston movements in the measuring tube (29) using a magnetic force acting between the piston sensor (57) and the piston (9). A transmitter/receiver (65) for the displacement measuring device is positioned on one of the housing covers (5, 7) and emits a measurement beam through the open end (25, 26) of the measuring tube (29) to the position sensor (57) and receives reflected radiation.

A fluidic control system (1) for controlling a vehicle, which includes a controller (2) and a closed fluidic circuit. The circuit includes a pump (3) for pressurizing fluid in the circuit, valve means (40, 50, 60), an actuator (4, 5, 6) and a precharge accumulator (7). The valve means (40, 50, 60) is fluidly connected to the inlet and outlet of the pump (3) and the actuator (4, 6) is fluidly connected to the valve means (40, 50, 60) for selectively receiving pressurized fluid therefrom. The precharge accumulator (7) includes a movable member (73, FIG. 2) that describes a variable volume (71) fluidly connected to the circuit between the valve means (40, 50, 60) and the inlet of the pump (3). The system (1) also includes a sensor (70) for determining the position of the movable member (73) for estimating the quantity of fluid and/or detecting an abnormal pressure variation within the circuit.

A system filled with a fluid, designed for underwater applications, in which the interior of a housing and/or tank forms a fluid region which is sealed with respect to the surrounding seawater region, includes at least one hydraulic pressure compensation device, which at least raises the pressure level of the fluid region to the ambient pressure prevailing in the seawater region. The pressure compensation device is constructed in two stages in such a way that at least one store having a flexible wall region and at least one piston store having a displaceable piston are arranged in series. The use of the pressure compensation device to pressurize at least one housing filled with fluid for a hydraulic actuating shaft is also proposed.

A method and system providing a pressurized fluid includes a pump having a pump inlet and a pump outlet, the pump to provide a fluid flow, a bypass path to direct the fluid flow from the pump outlet to the pump inlet, a load path having a load path pressure, the load path including: a fluid accumulator to accumulate a fluid volume, and at least one load device, a bypass regulator valve in fluid communication with the pump outlet, the bypass path, and the load path, and a controller to direct the fluid flow to the load path in response to the load path pressure being less than a low load path threshold pressure via the bypass regulator valve and to direct the fluid flow to the bypass path in response to the load path pressure being greater than a high load path threshold pressure via the bypass regulator valve.

A control system may receive sensor data indicative of respective fluid levels of two or more hydraulic accumulators configured to operate at respective target fluid levels within a hydraulic system. The control system may determine respective errors of the hydraulic accumulators based on the respective fluid levels and respective target fluid levels of the hydraulic accumulators. The respective errors may correspond to pressure errors, fluid volume errors, or other types of errors of the hydraulic accumulators. Responsive to determining the respective errors, the control system may determine that the error of a given hydraulic accumulator is greater than errors of the other hydraulic accumulators and provide instructions to control a hydraulic valve to supply fluid from a single pump of the hydraulic system to the given hydraulic accumulator.