An independent metering valve circuit includes an actuator, a set of independent metering valves, an independent metering valve pre-compensator, an inverse resolver, and a signal conditioning element. The set of independent metering valves are fluidly coupled to the actuator and configured to independently control a flow of a hydraulic fluid to the actuator. The independent metering valve pre-compensator is configured to control the flow of the hydraulic fluid to the set of independent metering valves. The inverse resolver is configured to receive a first pressure signal from the independent metering valve circuit and a second pressure signal from a load-sense hydraulic system and output a third pressure signal. The signal conditioning element is configured to receive the third pressure signal and output a forth pressure signal configured to control a pump fluidly coupled to the load-sense hydraulic system and the independent metering valve circuit.

A mixer drum driving apparatus includes an auxiliary fluid pressure pump that is provided independently of a fluid pressure pump and is capable of supplying a working fluid to a fluid pressure motor so as to cause a mixer drum to perform agitation rotation, a plurality of motors configured to drive the auxiliary fluid pressure pump to rotate, and a control unit that controls rotation of the mixer drum. When an engine is stopped during the agitation rotation of the mixer drum, the control unit drives the auxiliary fluid pressure pump to rotate by operating the plurality of motors selectively in accordance with a load of the mixer drum.

Systems and methods for electrohydraulic valve calibration are provided. In one aspect, a calibration circuit includes a calibration conduit isolated from a supply conduit, a first calibration orifice configured to provide fluid communication between the calibration conduit and a fluid source, and a second calibration orifice arranged in series with the first calibration orifice. The second calibration orifice is on a spool of a electrohydraulic control valve and is configured to selectively provide fluid communication between the calibration conduit and a low pressure source. The calibration circuit further includes a pressure sensor configured to measure a pressure in the calibration conduit between the first calibration orifice and the second calibration orifice. The second calibration orifice is isolated from the at least one workport of the electrohydraulic control valve.

Saturation of a secondary system pressure circuit (18) of a hydraulic system (4) of a motor vehicle transmission is earlier, in that an excess amount of oil from a primary system pressure circuit (16) of the hydraulic system (4) is not directed to a suction charging (40), but rather into the secondary system pressure circuit (18). This can take place via a system pressure valve (9) for the primary system pressure circuit (16), which is configured for this function.

A fluid system for a gas turbine engine includes a first supply line, a hydraulic accessory actuable by a fluid, and a second supply line fluidly connected the hydraulic accessory and to the first supply line upstream of the component. An accumulator is fluidly connected to the second supply line upstream of the hydraulic accessory. The accumulator is operable to fill a reservoir with the fluid from the first supply line via the second supply line, and to deliver the fluid to the hydraulic accessory via the second supply line. The first supply line may be a fuel or lubricant main supply line of the engine. A method of actuating a hydraulic accessory is also disclosed.

A system for delivering fluid in a machine is provided. The system includes a pump, a first valve disposed downstream of the pump, a check valve disposed downstream of the first valve, at least one accumulator disposed downstream of the check valve, and an auxiliary system disposed upstream of the check valve. The system further includes a control unit configured to receive a signal indicative of a fluid demand from the auxiliary system. The control unit is also configured to selectively control the first valve in a first position to limit flow of the fluid from the pump to the auxiliary system, and in a second position to allow flow of the fluid from the pump to the auxiliary system based, at least in part, on the received signal. The check valve limits flow of a fluid from the at least one accumulator to the auxiliary system.

A steam turbine valve drive apparatus in an embodiment includes a piston, a cylinder, a bidirectional pump, a servo motor, and a quick closing mechanism. The cylinder houses the piston in an inner space thereof, the inner space being partitioned by the piston into a first hydraulic chamber and a second hydraulic chamber. The quick closing mechanism executes a quick closing operation of closing the steam valve unit more quickly than the closing operation. Here, the quick closing mechanism executes the quick closing operation by feeding the working oil accumulated in an accumulator to the second hydraulic chamber and draining the working oil from the first hydraulic chamber.

Saturation of a secondary system pressure circuit (18) of a hydraulic system (4) of a motor vehicle transmission is earlier, in that an excess amount of oil from a primary system pressure circuit (16) of the hydraulic system (4) is not directed to a suction charging (40), but rather into the secondary system pressure circuit (18). This can take place via a system pressure valve (9) for the primary system pressure circuit (16), which is configured for this function.

The present invention is a hydraulically operated splitting device with a piston cylinder unit comprising an extending chamber and a retracting chamber in which a piston is supported, displaceable in an extending direction and a retracting direction, allowing the extending chamber and the retracting chamber to be impinged with pressurized hydraulic medium for moving the piston at a displacement speed, a cylinder housing at which a plurality of pressure pads is supported, displaceable perpendicular to the extending direction and the retracting direction, a wedged lance connected to a piston rod of the piston and mobile with said piston, which engages wedge-shaped pressure areas of the pressure pads complementary to the wedged lance, and moves the pressure pads perpendicular to the extending direction and the retracting direction, a lubrication unit by which lubricant can be inserted from a lubricant reservoir to an area between the wedged lance and the pressure pads, with the splitting device comprising a protective unit by which the displacement speed can be reduced depending on the fill level of the lubricant in the lubricant reservoir.

The invention relates to a pressure-limiting device designed to be installed in a system comprising a first line (11) and a second line (12) that can comprise pressurised oil, as well as comprising a discharge and/or booster line (10). The device also comprises a pressure selector (130, 150) in the form of a cage defining two seats (132, 134) and two pressure relief valves (160, 180). The limiting device is characterised in that it further comprises at least one means (170, 172; 190, 192) for regulating a pressure relief valve, disposed on the outside of an axial end of the pressure selector (150), in the form of a cage that allows the loading of the associated pressure relief valve to be regulated.