The invention provides a hydraulic circuit for feeding an actuator (1) comprising first and second chambers (5, 6), the circuit comprising a slide valve (10) with a slide (16) that is movable between first and second extreme positions (18, 19) on either side of a stable central position (17) so that: in the central position, it connects the chambers (5, 6) of the actuator to a return port; in the first extreme position (18), it connects the first chamber (5) to a feed port and the second chamber to the return port; and in the second extreme position (19), it connects at least the second chamber (6) to the feed port. According to the invention, the hydraulic circuit includes pressure-maintaining means (20) for maintaining pressure in the first chamber of the actuator while the slide is passing through the central position on being moved from the first extreme position to the second extreme position.

The invention relates to a control device for a hydraulic consumer (22), susceptible to vibrations, comprising a valve (24) having a control spool (40), which can be controlled by means of an actuating device (46), wherein the valve (24) has a pressure supply port (P), to which a pressure compensator valve can be connected, which can be supplied with pressure fluid from a pressure supply device, wherein the actuating device (46) has a motor (74) and wherein a load-pressure-dependent force on the control spool (40) can be generated by means of a control device (66). In accordance with the invention, this force at the control spool (40) acts on an electronic motor controller (208) of the DC motor (74), which detects a change of the force and acts as a damping of the vibrations of the consumer (22) against this change of force.

An example valve includes a first port fluidly coupled to a source of fluid, a second port fluidly coupled to an actuator, a third port fluidly coupled to a reservoir, and a fourth port configured to export a load-sense (LS) fluid signal. The valve can operate in: a neutral state, wherein fluid is allowed to flow from the second port to the third port, while the first port and the fourth port are blocked; a first actuated state, wherein fluid flow is throttled from the second port to the third port, while the first port and the fourth port remain blocked; or a second actuated state, wherein fluid flow from the second port to the third port is blocked, while fluid flow is allowed from the first port to the second port and from the second port to the fourth port.

Manual hydraulic override pumps for use with actuators are described herein. An example apparatus includes a manifold including a reservoir port to be fluidly coupled to a reservoir of fluid, a pump port to be fluidly coupled to a pump, a first actuator port to be fluidly coupled to a first chamber of an actuator, and a second actuator port to be fluidly coupled to a second chamber of the actuator. The example apparatus also includes a rotor disposed in a cavity formed in the manifold. The rotor is rotatable between a first actuating position in which the rotor fluidly couples the first actuator port and the pump port, and a second actuating position in which the rotor fluidly couples the second actuator port and the pump port.

A valve includes a bore within a valve body having a central axis. A plurality of galleries in the bore define flow paths for hydraulic fluid. A spool is positioned in the bore, and the spool is moveable along the central axis between a first position in which hydraulic fluid from a central pump gallery is prevented from flowing to first and second working galleries and from flowing to one or more tank galleries; a second position in which hydraulic fluid from the central pump gallery is in fluid communication with both the first and second working galleries simultaneously; and a third position in which the first and second working galleries are in fluid communication with the one or more tank galleries simultaneously.

A directional-control valve is typically comprised of a valve spool that slides linearly within a valve body. The valve body typically includes five internal ports, which are covered or exposed as the spool slides within the body. The typical five-internal-port architecture precludes certain combinations of port connectivity when the spool is in the center position. For example, when the spool is in the center position, providing connectivity between the actuator ports, while simultaneously providing fluid isolation of the supply and exhaust ports, is not directly achievable with a standard five-port architecture. This application describes three embodiments that enable the aforementioned port connectivity when the spool is in the center position.

Valve device consisting of at least one valve piston (1) which is arranged in a valve housing (3) in such a way as to be longitudinally movable along a movement axis (5) by an electric motor (23) and which at least partially connects or disconnects fluid connection points (P, A, B) in the valve housing (3) to or from each other, said valve device being characterized in that the drive axis (25) of the electric motor (23) intersects the movement axis (5) of the valve piston (1), runs through the top face (6) and/or the bottom face (8) of the valve housing (3), and is arranged in the valve housing (3) in such a way as to extend (10) parallel or at an angle to the fluid connection points (P, A, B).

A spool valve device includes: a housing with channels; a spool moving to change channel connection statuses; an electric actuator including an electric motor and linear-motion conversion mechanism, the motor rotating an output shaft by torque corresponding to a drive current supplied to the motor, the mechanism converting rotational output shaft movement into straight movement and applying thrust corresponding to the torque to the spool to change position; a biasing member applying biasing force to the spool against the actuator thrust; an angle detector detecting an motor output shaft angular position; a driving portion driving the motor by controlling drive current flow supplied to the motor based on a position command input and the angular position detected by the angle detector; and an abnormality determining portion calculating the spool position based on the detected angular position and determine presence or absence of operation spool abnormality.

This industrial apparatus (2) comprises a pneumatic system (4), a first mechanical device (36) and a second mechanical device (38). The pneumatic system (4) includes: a first pneumatic actuator (6) for commanding the first mechanical device (36), a second pneumatic actuator (8) for commanding the second mechanical device (38), a pneumatic control valve (10) switchable between several states to command of the first and second actuators (6, 8). The control valve (10) comprises an actuation portion (56), movable in translation between: a resting position, corresponding to a first state (51), a first pushed position, corresponding to a second state (S2), and a second pushed position, corresponding to a third state (S3). The first pushed position corresponds to an intermediary position between the resting position and the second pushed position.

A pneumatic valve arrangement for a pneumatically operated field device, such as a control device, of a processing plant, such as a chemical plant, a foodstuff processing plant, a power plant or the like is disclosed. The valve arrangement may include an air supply conduit for receiving pressurized air from a source of pressurized air, a control air conduit for aerating and venting a pneumatic actor of the field device, and a venting conduit for discharging pressurized air to a pressure sink, such as the atmosphere; a venting valve for opening and/or closing the venting conduit and an aerating valve for opening and/or closing the air supply conduit; and a pivotable carrier lever for common actuation of the aerating valve and of the venting valve, wherein the carrier lever holds the venting valve in its closed position while it opens the aerating valve from its closed position.