A hydraulic system for operating a hydraulic fall-back support of a work machine including at least one hydraulic fall-back support cylinder for tracking and limiting movements of a boom of the work machine and a hydraulic pump by means of which the fall-back support cylinder and at least one further hydraulic consumer can be supplied with hydraulic fluid. A stop valve having a blocking position and a passage position is connected between the hydraulic pump and the fall-back support cylinder, by means of which the stop valve and a load-bearing cylinder space of the fall-back support cylinder is blockable and a hydraulic store connected to the load-bearing cylinder space is provided between the stop valve and the fall-back support cylinder.

Disclosed is a device for relieving pressure in hydraulic lines, in particular in connecting lines that have coupling points (6, 8) and are located between attachments comprising hydraulically actuated actuators and working implements supplying said attachments. The disclosed device comprises a control block (2) which is connected to the line to be relieved and which includes an openable non-return valve (12) as a relief valve, a pressure accumulator (22) which holds a relieving volume when the non-return valve is open, and an actuating member (38) which can be moved manually in order to open the non-return valve (12) and which is arranged so as to be movable on the housing (24) of the pressure accumulator (22).

A method for selectively coupling or uncoupling a coupling with a release, arranged between the supply conduit and a cylinder, on the basis of pressure in a supply conduit. The method includes providing an operating pressure prevailing in the supply conduit in order to provide hydraulic liquid to the cylinder on the basis thereof, and providing an uncoupling pressure prevailing in the supply conduit for the purpose of activating shut-off valves in the supply conduit and on the cylinder, and activating a release which uncouples the coupling. A coupling for respectively coupling and uncoupling a supply conduit which is connected to the coupling to/from a cylinder, as well as to an assembly including a pump, a cylinder, a supply conduit between the pump and the cylinder, and such a coupling.

A method for selectively coupling or uncoupling a coupling with a release, arranged between the supply conduit and a cylinder, on the basis of pressure in a supply conduit. The method includes providing an operating pressure prevailing in the supply conduit in order to provide hydraulic liquid to the cylinder on the basis thereof, and providing an uncoupling pressure prevailing in the supply conduit for the purpose of activating shut-off valves in the supply conduit and on the cylinder, and activating a release which uncouples the coupling. A coupling for respectively coupling and uncoupling a supply conduit which is connected to the coupling to/from a cylinder, as well as to an assembly including a pump, a cylinder, a supply conduit between the pump and the cylinder, and such a coupling.

A petroleum pipeline safety system for preventing contamination of an environmentally sensitive area close to a pipeline includes an upstream portion of the pipeline supplying a flow of fluid material, a crossing portion of the pipeline receiving the flow of fluid material from the upstream portion and conveying the flow of fluid material through the environmentally sensitive area to a downstream portion of the pipeline, the downstream portion, a pipeline pressure activated valve selectively capable of blocking the flow of fluid material from entering the crossing portion based upon a change in pressure within the crossing portion, and a fluid capacitor connected to the upstream portion configured to filter out a pressure spike in the upstream portion associated with the valve blocking the flow of fluid material.

An electrohydraulic control circuit for driving a hydraulically actuated actuating element (5, 6), by means of which a segment (5.3) of a manipulator, in particular of a large manipulator for truck-mounted concrete pumps, can be adjusted in terms of its orientation, wherein there are provided an electrically driven first valve (2.4), which is connected to hydraulic working lines of the actuating element (5.6) for the drive thereof, and leak-free check valves (2.5, 2.6) provided in the working lines of the actuating element (5.6), which valves are arranged on the actuating element (5.6) or on the segment (5.3) associated with this actuating element (5.6) and can be released for the normal operation of the actuating element (5.6), wherein the release of the check valves (2.5, 2.6) is driven by an electronic control unit (ECU) separate from the first valve (2.4) and the check valves (2.5, 2.6).

The various embodiments herein provide a coaxial hydraulic actuator assembly for an aircraft hydraulic system for providing the dual redundancy operations in normal and emergency operations. The embodiments herein adopt a coaxial hydraulic cylinder based actuator system comprising a conventional fixed cylinder with a moving piston actuator. The fixed cylinder with a moving piston actuator is located in a first region. The fixed cylinder with the moving piston actuator is manufactured in tandem with a moving cylinder with fixed piston actuator. The moving cylinder with a fixed piston actuator is located in a second region. The fixed piston actuator in the second region is also referred to as actuation rod. Further, the coaxial hydraulic cylinder based actuator system comprises a first adapter and a first cap for the first region. Similarly, a second adapter and a second cap are provided for the second region.

Many operators choose not to utilise partial-stroke testing arrangements even when the equipment required for it to be performed is available, due to a perceived risk of over-travel and/or spurious trip. To alleviate this, we describe a safety valve system comprising a valve operable to move between an operating state and a safe state, a valve actuator operatively connected to the valve to control its state, and including a bias toward the safe state, a pair of drive members powered by a pressure media, each acting against the bias to urge the valve toward the operating state, a first control valve arranged to selectively convey pressure media to both drive members and to withdraw supply on receipt of a safety trigger, and a second control valve arranged to selectively convey pressure media to one drive member only of the pair and to withdraw supply on receipt of a test signal. In this way, a partial stroke test is possible via the second control valve, but the other drive member of the pair will remain active thus acting as a buffer that prevents excessive movement of the valve.

A valve group includes an inlet module and at least one service module connected to the inlet module, the inlet module having a housing, a pressure port, a pressure gallery, a tank port, a tank gallery, a spool movable in the housing to interrupt in a first position a connection between the pressure port and the pressure gallery and to connect in a second position the pressure port and the pressure gallery. A first pressure transducer is provided to detect a first pressure in the pressure gallery and a second pressure transducer is provided to detect a second pressure in the tank gallery, the pressure transducers being connected to a controller determining the position of the spool based on the pressures read from the pressure transducers.

A ram air turbine control valve includes a sleeve, a spool, and a return housing. The sleeve defines a first exit port disposed proximate a first end of the sleeve and defines a second exit port disposed between the first exit port and the first end. The spool is radially contained within the sleeve and is movable between a first position and a second position. The return housing is coupled to the first end of the sleeve and defines a cavity that receives a biasing member that engages the spool.