The present invention relates to a hydraulic switch arrangement and a fluid switch for incorporating into a hydraulic switch arrangement that may be included in a hydraulic circuit for inhibiting flow of hydraulic fluid through a hydraulic circuit in the event of movement of an apparatus or platform from a stable to an unstable condition. Such platforms or apparatus may include for example, cranes, excavators, teletrucks and forklift trucks and roll over incidents of such machinery is common leading to numerous fatalities. Aspects of the present invention ensure fast switching in the event of a transfer from a stable to an unstable condition.

A stage assembly (10) includes a stage (14), and a fluid actuator assembly (24) that moves the stage (14). The fluid actuator assembly (24) includes a piston housing (32) that defines a piston chamber (34); (ii) a piston (36) that separates the piston chamber (34) into a first chamber (34A) and a second chamber (34B); (iii) a supply valve (38C) that controls the flow of the working fluid (40) into the first chamber (34A); and (iv) an exhaust valve (38D) that controls the flow of the working fluid (40) out of the first chamber (34A). The supply valve (38C) has a supply orifice (250G) having a supply orifice area, and the exhaust valve (38D) has an exhaust orifice (352G) having an exhaust orifice area. Moreover, the supply orifice area is different from the exhaust orifice area. Further multiple valves of different sizes can be used in combination for the supply and exhaust for each chamber (34A), (34B).

An example valve includes: (i) a valve body defining a longitudinal cavity, where the valve body includes a supply inlet and an operating outlet; (ii) a cage disposed in the longitudinal cavity, where the cage includes (a) a first opening fluidly coupled to the supply outlet, and (b) a second opening fluidly coupled to the operating outlet; and (iii) a spool mounted within the cage and configured to move axially therein. When the valve is actuated, the spool moves within the cage to form a gap, thereby allowing pressurized fluid to flow from the supply inlet through the first opening, the gap, and the second opening to the operating outlet. A flow area defined around an exterior peripheral surface of the spool changes upstream from the gap at a first rate, and changes downstream from the gap at a second rate that is different from the first rate.

An apparatus includes a hydraulic circuit that is configured to selectively open fluid communication between one portion of the hydraulic circuit and another portion of the hydraulic circuit, such as a reservoir, based on the flow of the hydraulic fluid in the one portion. When the flow of hydraulic fluid exceeds a selected threshold in the one portion of the hydraulic circuit, the flow of fluid urges the opening of a hydraulic component of the hydraulic circuit to allow fluid communication between the one portion and the reservoir to discharge fluid from the one portion.

A hydraulic system is provided. The hydraulic system includes a pump, a load sense conduit, a tank conduit, a function workport, and a function control valve. The hydraulic system further includes a function poppet valve arranged between the function workport and the function control valve and having a function poppet vent passage, and a system control valve arranged downstream of the function control valve. The system control valve is biased into a first position where fluid communication between the function poppet vent passage and the tank conduit is prevented and fluid communication between the load sense conduit and the tank conduit is provided. The system control valve is selectively movable to a second position where fluid communication between the function poppet vent passage and the tank conduit is allowed and fluid communication between the load sense conduit and the tank conduit is prevented.

A control system can include a resettable chamber and a bidirectional valve. The bidirectional valve can be switchable between (i) a first configuration for enabling fluid flow from the control line into a first port of a well tool and from a second port of the well tool into the resettable chamber, and (ii) a second configuration for enabling fluid flow from the control line into the second port of the well tool and from the first port of the well tool into the resettable chamber. The bidirectional valve can be switched from the first configuration to the second configuration in response to pressure being applied to the control line.

An example valve includes a main stage, a pilot stage, and a solenoid actuator. The main stage includes a sleeve and a piston axially movable within the sleeve. The piston defines a cavity therein. The pilot stage includes a pilot pin received at, and axially movable in, the cavity of the piston, where the piston forms a pilot seat at which the pilot pin is seated when the valve is in a closed state. The solenoid actuator includes a solenoid coil, an armature, and a solenoid spring. The solenoid spring applies a biasing force in a distal direction on the pilot pin to seat the pilot pin at the pilot seat. Energizing the solenoid coil causes the armature to move in a proximal direction, thereby reducing the biasing force that the solenoid spring applies on the pilot pin.

A pneumatic trip valve that may include a valve structure, a switch plate air path and an internal check valve. In various aspects, the pneumatic trip valve may be connected to a valve positioner, an actuator, or a combination thereof to control the operation of a fluid process control valve. In operation, the Pneumatic trip valve acts to put the actuator in a preset fail-safe position when the actuator loses sufficient pressure or communication from a main air supply, stored pressurized air from an actuator air reservoir, and/or an external air reservoir.

An example valve includes: (i) a valve body defining a longitudinal cavity, where the valve body includes a supply inlet and an operating outlet; (ii) a cage disposed in the longitudinal cavity, where the cage includes (a) a first opening fluidly coupled to the supply outlet, and (b) a second opening fluidly coupled to the operating outlet; and (iii) a spool mounted within the cage and configured to move axially therein. When the valve is actuated, the spool moves within the cage to form a gap, thereby allowing pressurized fluid to flow from the supply inlet through the first opening, the gap, and the second opening to the operating outlet. A flow area defined around an exterior peripheral surface of the spool changes upstream from the gap at a first rate, and changes downstream from the gap at a second rate that is different from the first rate.

A logic valve for management of a hydraulic actuator comprising: a valve body with a hollow seat which extends along a work direction and communicates with a first port adapted for receiving a pressurized working fluid, a second port adapted for fluidly coupling with an operating chamber of the hydraulic actuator, and a third port adapted for discharging the working fluid; a slider within the hollow seat movable along the work direction; and a spring between the valve body and the slider and oriented to act on the slider along the work direction in the direction away from said third port, wherein the slider is movable between a first operating configuration fluidly coupling the second and third ports and excluding fluid communication between them and the first port, and a second operating configuration fluidly coupling the first and second ports and excluding fluid communication between them and the third port.