Abstract: The present disclosure provides a heat exchanger system for a servovalve, comprising a base comprising a supply port in fluid communication with a return port, a first passage for fluid connection to a source of cooling fluid, and a second passage in fluid communication with the return port. The system further comprises one or more pipes located over a surface of the base, the one or more pipes fluidly connected between the first passage and the second passage, such that in use cooling fluid may flow from the first passage to the second passage via the network of pipes.

Abstract: A multiple-stage fractal heat exchanger includes two or more first fluid flow paths arranged adjacent to one another. Each first fluid flow path is defined by a main inlet channel on one side which diverges into two or more smaller channels to form a central first fluid flow path. In each of the two or more first fluid flow paths. The two or more smaller channels converge away from the central first fluid flow path into a main outlet channel on an opposite side of the first fluid flow path to the main inlet channel. The main outlet channel of each of the two or more first fluid flow paths is configured to be connected to the main inlet channel of an adjacent first fluid flow path.

Abstract: A heat exchanger comprises: a plurality of first fluid channels defining a flow path for a first fluid; a first fractal channel for conveying the first fluid to the plurality of first fluid channels; and a second fractal channel for conveying the first fluid from the plurality of first fluid channels; wherein the first fractal channel and the second fractal channel each comprises at least one divergence point along its length where a parent channel splits into a plurality of sub-channels which diverge away from each other, and wherein one or each of the first fractal channel and the second fractal channel defines one or more through-channels for a second fluid to pass through the respective fractal channel, each through-channel extending from a parent channel side of a divergence point and emerging between the corresponding sub-channels on a sub-channel side of the divergence point.

Abstract: A nozzle with changeable press fit and a method for calibrating a nozzle is described. The nozzle may be used in a nozzle/flapper type servovalve. The method comprises the steps of providing a nozzle within a cylindrical body defining a cylindrical bore, the nozzle having a tubular shape with an outer cylindrical surface and an inner radial surface, the method further comprises the steps of positioning a first, tubular locking member within the nozzle, and axially moving the first, tubular locking member within the nozzle. The first tubular locking member is configured to cause the nozzle to become positionally fixed at a selected position within the bore in response to the first, tubular locking member being axially moved relative to the nozzle. A nozzle positioning system is also described herein.

Abstract: A servo valve for an actuator is described. The servo valve comprises a housing having a plurality of ports, a sleeve disposed within the housing, the sleeve comprising an axis (A), an inner surface defining a cavity for the servo valve and a plurality of metering holes, each in communication with one of the ports, and a metering rod extending axially in the cavity for reciprocation along the axis to meter flow through the metering holes. The servo valve additionally comprises a first spring seal extending between the metering rod and the sleeve to close off a first end of the cavity and a second spring seal extending between the metering rod and the sleeve to close off a second, opposite end of the cavity.

Abstract: 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.

Abstract: A servo valve for an actuator comprises a housing, a sleeve provided within the housing comprising an axis (A) and having a plurality of metering holes for communication with a cavity within. A metering rod extends within the cavity for metering flow of pneumatic fluid through the metering holes. The metering rod is coupled to a drive unit for axial movement within the cavity, the drive unit comprising a drive unit housing, a solenoid and an adjustable core. The adjustable core comprises a threaded first portion having a thread and a second portion. The thread of the first portion engages a thread extending through the drive unit housing for adjustment of the relative position of the adjustable core with respect to the solenoid.

Abstract: A coupling suitable for use in a flexible shaft includes a first and second shaft engagement means each having a central axis, a spacer means having a central axis, and a number of support wires. A first set of support wires each extends between the first shaft engagement means and the spacer means one or more times, the first set of support wires comprises at least one support wire, and the first and second shaft engagement means and the spacer means have a common axis (A) when the coupling means is not subject to any misalignment.

Abstract: A hydraulic valve is disclosed comprising a venting passage for allowing fluidic communication between an interior and an exterior of the hydraulic valve, the venting passage having a first portion following a first path extending in a first plane, and a second portion following a second path extending in a second plane, wherein the first plane is at an angle to the second plane, and wherein the first and/or second path is a labyrinth path in its respective plane.

Abstract: A heat exchanger comprises: a plurality of first fluid channels defining a flow path for a first fluid; a first fractal channel for conveying the first fluid to the plurality of first fluid channels; and a second fractal channel for conveying the first fluid from the plurality of first fluid channels; wherein the first fractal channel and the second fractal channel each comprises at least one divergence point along its length where a parent channel splits into a plurality of sub-channels which diverge away from each other, and wherein one or each of the first fractal channel and the second fractal channel defines one or more through-channels for a second fluid to pass through the respective fractal channel, each through-channel extending from a parent channel side of a divergence point and emerging between the corresponding sub-channels on a sub-channel side of the divergence point.

Abstract: A helical fractal heat exchanger comprises a heat exchanger core defining a plurality of helical, first fluid conduits arranged in a two-dimensional grid configuration, and plurality of helical, second fluid conduits in thermal communication with the first fluid conduits. A first fluid inlet structure splits a first fluid from a first fluid inlet of the heat exchanger and supplies it to each of the plurality of first fluid conduits, and a first fluid outlet structure recombines the first fluid from the plurality of first fluid conduits and conveys it to a first fluid outlet of the heat exchanger. The first fluid inlet and outlet structures are each fractal structures comprising at least two multi-furcation stages in which a parent channel divides into two or more sub-channels that diverge away from each other.

Abstract: A torque motor for use in a servovalve wherein only two holes must be provided through each of the pole pieces in order to assemble the torque motor together. The torque motor comprises first and second opposing pole pieces, first and second permanent magnets positioned between the first and second pole pieces; an armature comprising a magnetic plate and a flapper, the magnetic plate being positioned between the first and second permanent magnets, the flapper being connected at one end to the magnetic plate; and further comprising: first and second fastening means each extending through the first pole piece, the armature and the second pole piece to thereby fasten the torque motor together.

Abstract: A multiple-stage fractal heat exchanger includes two or more first fluid flow paths arranged adjacent to one another. Each first fluid flow path is defined by a main inlet channel on one side which diverges into two or more smaller channels to form a central first fluid flow path. In each of the two or more first fluid flow paths. The two or more smaller channels converge away from the central first fluid flow path into a main outlet channel on an opposite side of the first fluid flow path to the main inlet channel. The main outlet channel of each of the two or more first fluid flow paths is configured to be connected to the main inlet channel of an adjacent first fluid flow path.

Abstract: The present disclosure provides a heat exchanger system for a servovalve, comprising a base comprising a supply port in fluid communication with a return port, a first passage for fluid connection to a source of cooling fluid, and a second passage in fluid communication with the return port. The system further comprises one or more pipes located over a surface of the base, the one or more pipes fluidly connected between the first passage and the second passage, such that in use cooling fluid may flow from the first passage to the second passage via the network of pipes.

Abstract: The disclosure provides a method of securing a feedback spring relative to a spool of a servovalve, the method comprising inserting the feedback spring at least partially into an internal cavity of the spool, inserting two fixing members into the internal cavity such that they each oppose a portion of the feedback spring, bringing the fixing members into respective set positions, such that the fixing members clamp the feedback spring and prevent relative movement between the feedback spring and the spool, and securing the fixing members in their respective set positions, such that the fixing members remain in their clamping positions and prevent relative movement between the feedback spring and the spool.

Abstract: A torque motor for a servovalve is provided, the torque motor comprising an armature and a first pole piece. The first pole piece has a first portion and a second portion that is selectively moveable relative to the first portion such that a size of an air gap formed between the second portion and the armature is adjusted in response to the movement of the second portion relative to the first portion.

Abstract: The present disclosure provides a heat exchanger system for a servovalve, comprising a base comprising a supply port in fluid communication with a return port, a first passage for fluid connection to a source of cooling fluid, and a second passage in fluid communication with the return port. The system further comprises one or more pipes located over a surface of the base, the one or more pipes fluidly connected between the first passage and the second passage, such that in use cooling fluid may flow from the first passage to the second passage via the network of pipes.

Abstract: A new method of forming a torsion spring for use in a servovalve is described. The method comprises individually forming the different components of the torsion spring and then connecting the individual components together using a brazing process. The torsion spring created by this method is also described.

Abstract: A system is described for positioning and locking in place a nozzle within a cylindrical bore of a body, and a method for positioning and locking in place a nozzle within a cylindrical bore of a body is also described. The system has a nozzle having a tubular shape extending between a first end and a second end with an outer cylindrical surface and an inner surface, said inner surface comprising a thread. The system also has a locking member provided within said nozzle and comprising an outer circumferential surface having a thread that corresponds to the thread of the inner surface of the nozzle. The system also has means for providing torque to said locking member to screw said locking member into and within said nozzle via said threaded surfaces to thereby create a press-fit between said outer cylindrical surface and an inner surface of said cylindrical bore.

Abstract: A valve assembly includes a valve housing having a bore formed therein. The bore has an axis A and comprises a circumferentially extending groove formed at an end portion. An axially outer wall of the groove includes at least two circumferentially spaced radially inwardly extending retaining elements defining an axial slot therebetween. An end cap is received in the end portion of the bore and closes the end of the bore. The end cap includes a retaining portion that includes at least one radially outwardly extending retaining element which is shaped to be insertable through the axial slot into the groove and rotatable therein to a retaining position in which the radially outwardly extending retaining element aligns with one of the radially inwardly extending retaining elements to prevent axial withdrawal of the end cap from the bore.