A hydraulic device having: a plurality of main piston-cylinder arrangements, each of the respective pistons having a fixed stroke length and configured for axial reciprocation within their respective cylinder; a plurality of flow control valves for switching between a lockdown state and an unlocked state of one or more of the plurality of main piston cylinder arrangements during operation of the hydraulic device; and one or more control valves for directing the plurality of flow control valves between their respective unlock and lock positions.

A pressure exchanger includes a rotor forming a duct from a first duct opening to a second duct opening. The pressure exchanger further includes a floating piston configured to move within the duct between the first duct opening and the second duct opening to prevent mixing of a first fluid and a second fluid while exchanging pressure between the first fluid and the second fluid. The pressure exchanger further includes a first adapter plate configured to prevent the floating piston from exiting the duct at the first duct opening and a second adapter plate configured to prevent the floating piston from exiting the duct at the second duct opening. The first adapter plate forms a first aperture that directs the first fluid to the first duct opening and the second adapter plate forms a second aperture that directs the second fluid to the second duct opening.

A hydraulic device having: a plurality of main piston-cylinder arrangements, each of the respective pistons having a fixed stroke length and configured for axial reciprocation within their respective cylinder; a plurality of flow control valves for switching between a lockdown state and an unlocked state of one or more of the plurality of main piston cylinder arrangements during operation of the hydraulic device; and one or more control valves for directing the plurality of flow control valves between their respective unlock and lock positions.

Provided is a double nozzle type positioner, which includes a flapper (1), a first nozzle (2) and a second nozzle (3) disposed at both sides based on the flapper (1), a first orifice (4) configured to maintain a constant pressure of the first nozzle (2), a second orifice (5) configured to maintain a constant pressure of the second nozzle (3), a first pilot valve (6) having an input portion connected to a feed pressure, a second pilot valve (7) having an input portion connected to an output portion of the first pilot valve (6), a discharge hole (8) connected to an output portion of the second pilot valve (7), and an actuator (9) connected to the output portion of the first pilot valve (6) and the input portion of the second pilot valve (7). If the first nozzle (2) is opened due to the movement of the flapper (1), the second nozzle (3) is closed, and if the first nozzle (2) is closed, the second nozzle (3) is opened.

A transducer for a connection to a fluid pressure source having a mechanism for setting a pneumatic output by way of an electrical input signal. The transducer provides a lower housing assembly and an upper housing assembly. The lower housing assembly comprises lower housing configured to receive a supply nozzle. The supply nozzle fluidly communicates with a supply port and intermittently fluidly communicates with an output port of the lower housing through an internal fluid passageway. The lower housing further comprises an exhaust nozzle fluidly communicating with an exhaust port and intermittently fluidly communicates with the output port of the lower housing through the internal fluid passageway. The upper housing assembly comprises an upper housing configured to receive a coil and an armature such that the upper housing, coil and armature define a latching electromagnetic circuit that provides alternating contact of the armature with the supply nozzle and the exhaust nozzle of the lower housing assembly.

A nozzle of or for a servo valve comprises a nozzle element having a fluid outlet at a first axial end and a tubular body extending from the first end to an opposed, second axial end. The nozzle further comprises a plug element mounted in and closing the second axial end of the tubular body, thereby defining an internal cavity within the tubular body. One or more openings are formed through the tubular body to fluidly communicate with the internal cavity. A filter may be mounted across the internal cavity at a position axially intermediate the openings and the fluid outlet.

A hydraulic stage includes a hydraulic element located between and sealing a first and second chamber, wherein the first chamber comprises at least one aperture through which fluid is arranged to flow into or out of the first chamber; and at least one piezoelectric element which is positioned adjacent to the at least one aperture and is arranged to deform in response to an applied potential difference such that it blocks or obstructs the at least one aperture to a varying degree according to the level of deformation, so as to control fluid flow into or out of the first chamber. The level of deformation of the piezoelectric element thus reduces or increases an effective size of the inlet or outlet aperture to which it is adjacent, restricting or permitting an increase in fluid flow accordingly.

An integral flapper and nozzle structure for a servo valve assembly whereby the flapper, orifices and nozzles are formed by sheets of metal formed into a single component.

A servo valve assembly includes a housing defining a cylindrical cavity having a central axis, and a spool disposed in the cavity and co-axially aligned with the central axis. A pair of transition portions define opposing conical cavity surfaces each connect a respective one of first and second cylindrical cavity portions with a third cylindrical cavity portion. The spool comprises a pair of blocking members projecting radially, and each of the blocking members defines a conical blocking surface opposing a respective one of the conical cavity surfaces to define a fluid flow passage therebetween. A cone angle of each conical blocking surface relative to the central is equal to a cone angle of the opposing conical cavity surface relative to the central axis. The spool is moveable along the central axis to vary a flow area of the flow passages between the conical blocking surfaces and the conical cavity surfaces.

An integral flapper and nozzle structure for a servo valve assembly whereby the flapper, orifices and nozzles are formed by sheets of metal formed into a single component.