Systems and methods for protecting a turbomachine may include a trip throttle valve having a throttle valve assembly and a trip valve assembly. The trip valve assembly may include a plurality of trip valves fluidly coupled to a hydraulic cylinder of the throttle valve assembly via a first flow path and a second flow path in parallel with one another. The trip valve assembly may also include a plurality of isolation valves fluidly coupled to the hydraulic cylinder via the first flow path and the second flow path. The plurality of isolation valves may be configured to selectively prevent fluid communication between the plurality of trip valves and the hydraulic cylinder to allow testing of one or more of the plurality of trip valves during operation of the turbomachine.

An example valve includes: a piston movable between a neutral position and an actuated position, wherein in the neutral position: a second port of the valve is fluidly coupled to a first port, and a third port is fluidly decoupled from the second port; a solenoid actuator sleeve movable between an unactuated state and an actuated state, wherein in the actuated state, the solenoid actuator sleeve allows pilot fluid to apply a fluid force on a piston in a distal direction; a first feedback spring; and a second feedback spring disposed in series with the first feedback spring, wherein the first feedback spring and the second feedback spring cooperate to apply a biasing force in a proximal direction on the piston against the fluid force, wherein the piston is configured to move to the actuated position based on a relationship between the fluid force and the biasing force.

A directional control system of a marine vessel includes a steering control member manually operated by a user and operationally connected to a direction-variation member acting on or in the water, such as at least one rudder blade or at least one outboard engine, the direction-variation member having an angular position that is controlled by the steering control member; and a locking system locking the free variation of the angular position of the direction-variation member, which can be activated and deactivated to allow the variation of angular position and carry out a directional change, the locking system including a hydraulic cylinder having a piston dividing the cylinder into two chambers, which are connected by a bypass circuit that can be opened and closed by a switching member.

A monitoring device includes a first pressure sensor that detects a first pressure value of a pressurized fluid in a first pipe, a second pressure sensor that detects a second pressure value of a pressurized fluid in a second pipe, and a detector that determines, on the basis of the first pressure value and the second pressure value, whether or not a piston has reached one end or the other inside a cylinder body.

A pneumatic actuator for controlling a valve, having a working piston which is movably accommodated in a cylinder housing along a movement axis and delimits a working space of variable size with the cylinder housing and which is connected to a piston rod which extends along the movement axis, the cylinder housing including a first outer body with a sleeve-shaped first piston rod guide and a second outer body with a sleeve-shaped second piston rod guide, wherein the two piston rod guides are arranged spaced apart from one another along the axis of movement, the working space being bounded by the first outer body and by the second outer body, and the piston rod passing through the end of the cylinder housing, wherein the piston rod is provided with a sealing in order to form a sealing connection with the associated piston rod guide.

A work machine has a controller which has an area limiting control section correcting the pilot pressures of pilot lines, a regeneration control section adjusting the flow rate of the hydraulic fluid caused to flow from a tank side line of an arm cylinder into a pump side line thereof between zero and a predetermined upper limit value, and a regeneration control switching section that issues an order to the regeneration control section to set the predetermined upper limit value to a first set value when the function of the area limiting control section is invalid and that issues an order to the regeneration control section to set the predetermined upper limit value to a second set value that is smaller than the first set value when the function of the area limiting control section is effective.

The invention relates to a hydraulic drive (1) comprising a working cylinder (2) and a travel cylinder (3) which is mechanically connected to the working cylinder (2). The working cylinder (2) and the travel cylinder (3) each comprise an upper and a lower cylinder chamber (21, 22, 31, 32), and all four cylinder chambers (21, 22, 31, 32) of the working and travel cylinder (2, 3) are connected to one another in a suitable manner in a closed pressure circuit (4) which is filled and prestressed with a hydraulic fluid (F). A rotational speed-variable hydraulic machine (5) with a first and second pressure connection (51, 52) is arranged in the pressure circuit (4) in order to conduct the hydraulic fluid (F) between the individual cylinder chambers (21, 22, 31, 32) of the working and travel cylinder (2, 3) during the operation (B) of the hydraulic drive (1). At least one first and second distributing valve (6, 7) are arranged in the pressure circuit (4) such that the respective valve switch positions (61, 62, 71, 72, 73) which are suitable for the different operating phases of the hydraulic drive (1) together with the suitably driven hydraulic machine (5) allow a common movement of the work and travel cylinder (2, 3) in one or the other piston movement direction (R1, R2). For this purpose, preferably only the first and the second distributing valve (6, 7) are arranged in the pressure circuit (4). The hydraulic drive (1) requires a minimum number of components, maintains a low installation complexity, improves the energy efficiency, can be constructed in a compact manner, and can be operated in a sufficiently variable manner.

An electrohydraulic linear actuator comprises a housing consisting of a tubular profile, which forms a housing shell and in which there is a plurality of cavities, and which is closed at the ends by two housing covers fitted to the ends of the housing shell. A first cavity of the tubular profile forms a cylinder which forms the hydraulic cylinder of a double-acting synchronous cylinder and a second cavity which extends parallel to the first cavity accommodates a hydraulic unit in addition to the hydraulic cylinder, and a hydraulic oil reservoir is formed in said second cavity. Two working chambers of the hydraulic cylinder are separated from each other by a piston unit. The housing has at least one through-hole for a coupling element which forms a mechanical interface with the piston unit. The electric motor of the hydraulic unit is configured as a brushless outrunner motor.

A redundant balance line operating system including first and second control lines, first and second balance lines, a first and second compensators and first and second actuators, the components being hydraulically connected to operate redundantly and to fail safe.

An electro hydrostatic actuator comprises a hydraulic pump driven by an electric motor to supply hydraulic fluid to a hydraulic actuator. The pump comprises an inlet and an outlet for the hydraulic fluid and an active flow path arranged therebetween such that, in an active mode of operation when the pump is driven by the electric motor, hydraulic fluid is actively drawn in through the inlet and exhausted out through the outlet. The pump further comprises a bypass flow path arranged to open between the inlet and outlet such that, in a damping mode of operation when the pump is not driven by the electric motor, hydraulic fluid is able to pass through the pump along the bypass flow path between the inlet and outlet.