A monitoring device for determining a position of a displacement piston (1) guided longitudinally movably in a housing (7) and, in the housing (7) and delimits a fluid chamber (3, 5) with a variable volume and connected via a pressure supply connector (9, 11) to a pressure fluid control device (13). A volumetric flow regulating device (45) and a pressure determining device (47) are connected between the pressure fluid control device (13) and the measuring connector (15, 17) of the fluid chamber (5, 3). The pressure determining device (47) outputs a measuring signal when the displacement piston (1) reaches an end position.

Embodiments of the present disclosure describe both mechanically-operated and electrically-operated, locally-actuated partial stroke testing devices and systems for testing operation of an emergency isolation valve.

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.

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

A hydraulic fluid energy regeneration apparatus of a work machine includes: a regeneration hydraulic motor driven by a return hydraulic fluid; a first hydraulic pump mechanically connected to the regeneration hydraulic motor; a second hydraulic pump that delivers a hydraulic fluid for driving a hydraulic actuator; a confluence line that causes the hydraulic fluid delivered from the first hydraulic pump to join the hydraulic fluid delivered from the second hydraulic pump; a first adjuster configured to adjust the flow rate of the hydraulic fluid of the first hydraulic pump; and a second adjuster configured to adjust the delivery flow rate of the second hydraulic pump. A control device includes: a first calculation section configured to calculate a non-confluence time pump flow rate in the case where the hydraulic actuator is driven solely by the second hydraulic pump and calculate a control command output to the first adjuster such that the flow rate of the hydraulic fluid from the first hydraulic pump is equal to or lower than the non-confluence time pump flow rate; and a second calculation section configured to calculate a target pump flow rate by subtracting from the non-confluence time pump flow rate the flow rate of the hydraulic fluid from the first hydraulic pump and calculate a control command output to the second adjuster such that the target pump flow rate is attained.

A hydraulic system embodying a method for combining two or more hydraulic functions from operatively associated distributor valves to selectively increase fluid flow using only hydraulic switches and valves is provided. Each two or more preselected hydraulic functions may each have a piloted diverter valve operatively associated with the other(s) so that when a control valve of the first hydraulic function is selectively positioned to a maximum pressure the first diverter valve actuates the second (and other) diverter valve(s) to couple to the first hydraulic function. Solving the problem where a user has two hydraulic flows that are limited by the diameter/distance of the hoses or pipes to a maximum flow rate almost regardless of pressure but needs to increase that flow to efficiently perform a task.

A valve system for use with a cylinder having an extensible rod, includes first and second valve assemblies, each including an inlet/outlet port configured to selectively be coupled with a source of pressurized gas, a check valve biased toward a closed state and having a check valve body at least partially receivable within a first port of the cylinder, a flow control valve positioned in series between the inlet/outlet port and the check valve, and an inlet pilot port connected with the check valve for opening the check valve when supplied with pressurized gas. First and second pilot lines extend to the respective inlet pilot ports from respective outlet pilot ports of the opposite ones of the first and second valve assemblies. When pressurized gas is supplied to the inlet/outlet port of a valve assembly, pressurized gas is also supplied to the opposite inlet pilot port.

Embodiments of the present disclosure describe both mechanically-operated and electrically-operated, locally-actuated partial stroke testing devices and systems for testing operation of an emergency isolation valve.

A fluid pressure circuit for controlling a rod of a cylinder controlled in accordance with an operation command includes a tank, a fluid pressure actuator configured to pressurize fluid supplied from the tank for extending and retracting the cylinder, a flow control valve arranged between the fluid pressure actuator and the cylinder device configured to switch a flow passage of pressurized fluid and discharge via a first throttle return fluid from the cylinder, a variable regeneration switching valve configured to discharge return fluid from the cylinder to the flow control valve upon non-regeneration and upon regeneration, branch part of the return fluid and discharge via a second throttle the fluid branched, a regenerative motor configured for regeneration by fluid branched by the variable regeneration switching valve, and a third throttle connected in series with the first throttle upon the regeneration to limit flow of return fluid.

A cylinder main body of a fluid pressure cylinder includes a switch valve, a check valve, and a flow path communicating a high pressure air supply source with a head side cylinder chamber and communicating an exhaust port with a rod side cylinder chamber when the switch valve is at a second position. Another flow path communicates the head side cylinder chamber with the rod side cylinder chamber and the exhaust port when the switch valve is at the first position.