Patent Description:
A hydraulic manifold or fluidic tube gallery is a component that allows one or more fluids to enter and exit using various machined, cast, or otherwise manufactured fluid conduits. The conduits form a single component which reduces the overall packaging size and complexity when compared to standard pipes or tubes. The hydraulic manifold typically forms part of a fluid system, which can include a pump for driving the fluid through the system. In conventional hydraulic manifolds, in case of an overpressure event, such as that caused by a blocked conduit, the manifold is designed to contain the fluid until another component in the fluid system, such as the pump, fails.

Overpressure events can also be controlled by other methods, such as by using pressure relief valves or burst disks. Pressure relief valves are designed to open at a predetermined pressure to protect fluid systems from overpressure events. However, pressure relief valves are typically bulky, making them unsuitable for certain types of hydraulic manifolds. They can also suffer from reliability issues and can create areas of pressure loss within the fluid system. Burst disks are designed to rupture at a predetermined pressure differential across the disk to protect fluid systems from overpressure events. However, burst disks are not as effective when there is a transient pressure differential across the disk, and can burst unreliably.

There is therefore a need to develop a solution to address at least some of the aforementioned problems.

<CIT> discloses a pressure release device having two rupturable plates suitable for a liquid metal heated steam generator. The pressure release valve is designed to accommodate fast rising pressures due to reactions can be relieved.

<CIT> discloses a pressure-relieving device for a pressure vessel comprises a pair of spaced apart bursting discs.

<CIT> discloses a safety device for a pressure vessel comprises a pair of spaced apart bursting discs.

<CIT> discloses a gas turbine engine comprising a hydraulic fuse.

The scope of the disclosure is set out in the appended claims.

According to a first aspect of the present disclosure, there is provided a gas turbine engine comprising a hydraulic fuse comprising: a fuse body defining a plenum, the plenum comprising: an inlet configured to couple to a first fluid location; and an outlet configured to couple to a second fluid location. The hydraulic fuse further comprises a first fuse element arranged to close the inlet, the first fuse element configured to open the inlet when a pressure differential between the first fluid location and the plenum reaches a first threshold; and a second fuse element arranged to close the outlet, the second fuse element configured to open the outlet when a pressure differential between the plenum and the second fluid location reaches a second threshold, wherein the first threshold is higher than the second threshold. In an inactive state, the inlet is closed by the first fuse element and the outlet is closed by the second fuse element to prevent fluid flow through the plenum; and in an active state, the pressure differential between the first fluid location and the plenum reaches the first threshold to cause the first fuse element to open and permit fluid flow through the inlet, and the pressure differential between the plenum and the second fluid location reaches the second threshold to cause the second fuse element to open and permit fluid flow through the outlet.

The first fuse element may be frangible, such that the first fuse element is configured to fracture and open the inlet when the pressure differential between the first fluid location and the plenum reaches the first threshold. The second fuse element may be frangible, such that the second fuse element is configured to fracture and open the outlet when the pressure differential between the plenum and the second fluid location reaches the second threshold.

The first fuse element and/or the second fuse element may be configured to fracture at a respective predetermined fracture point.

The first fuse element and/or the second fuse element may be configured to fracture in a brittle manner.

The first fuse element and/or the second fuse element may be configured to fracture in a ductile manner.

The first fuse element and the second fuse element may be integrally formed with the fuse body.

The first fuse element and the second fuse element may each comprise a respective retention feature configured to retain the first fuse element and the second fuse element within the plenum in the active state.

The retention feature may be larger than the inlet and outlet.

The first fuse element and/or the second fuse element may be flexibly attached to the fuse body, such that in the active state, the first fuse element and/or the second fuse element may be configured to bend and remain attached to the fuse body to provide the retention feature.

The first fuse element and/or the second fuse element may comprise a plurality of ridges formed on a surface facing into the plenum.

The first fuse element and the second fuse element may be contained within a volume circumscribed by the fuse body.

In the inactive state, the first fuse element and the fuse body may form a substantially continuous fluid-washed surface facing the first fluid location, and the second fuse element and the fuse body may form a substantially continuous fluid-washed surface facing the second fluid location.

The hydraulic fuse may be formed by an additive manufacturing process.

The hydraulic fuse may further comprise: an extraction hole opening into the plenum; and a sealing element configured to close the extraction hole.

According to a second aspect of the present disclosure, there is provided a gas turbine engine comprising a hydraulic manifold comprising: a first fluid conduit and a second fluid conduit separated by a manifold wall; and a hydraulic fuse according to the first aspect, wherein the hydraulic fuse is disposed in the manifold wall between the first fluid conduit and the second fluid conduit, such that the first fluid location is in the first fluid conduit and the second fluid location is in the second fluid conduit.

The hydraulic fuse may be integrally formed with the manifold wall.

The hydraulic manifold may be formed by an additive manufacturing process.

According to a third aspect of the present disclosure, there is provided a gas turbine engine comprising a hydraulic manifold comprising: a fluid conduit defined by a manifold wall; and a hydraulic fuse according to the first aspect; wherein the hydraulic fuse is attached to the manifold wall, such that the first fluid location is in the fluid conduit and the second fluid location is an environment surrounding the hydraulic manifold.

With reference to <FIG>, a gas turbine engine is generally indicated at <NUM>, having a principal and rotational axis <NUM>. The engine <NUM> comprises, in axial flow series, an air intake <NUM>, a propulsive fan <NUM>, an intermediate pressure compressor <NUM>, a high-pressure compressor <NUM>, combustion equipment <NUM>, a high-pressure turbine <NUM>, an intermediate pressure turbine <NUM>, a low-pressure turbine <NUM> and an exhaust nozzle <NUM>. A nacelle <NUM> generally surrounds the engine <NUM> and defines both the intake <NUM> and the exhaust nozzle <NUM>.

The gas turbine engine <NUM> works in the conventional manner so that air entering the intake <NUM> is accelerated by the fan <NUM> to produce two air flows: a first air flow into the intermediate pressure compressor <NUM> and a second air flow which passes through a bypass duct <NUM> to provide propulsive thrust. The intermediate pressure compressor <NUM> compresses the air flow directed into it before delivering that air to the high-pressure compressor <NUM> where further compression takes place.

The compressed air exhausted from the high-pressure compressor <NUM> is directed into the combustion equipment <NUM> where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines <NUM>, <NUM>, <NUM> before being exhausted through the nozzle <NUM> to provide additional propulsive thrust. The high <NUM>, intermediate <NUM> and low <NUM> pressure turbines drive respectively the high-pressure compressor <NUM>, intermediate pressure compressor <NUM> and fan <NUM>, each by suitable interconnecting shaft.

Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. By way of example such engines may have an alternative number of interconnecting shafts (e.g., two) and/or an alternative number of compressors and/or turbines. Further the engine may comprise a gearbox provided in the drive train from a turbine to a compressor and/or fan.

In fluid systems, such as for fluid systems used in a gas turbine engine, a hydraulic fuse can be used to mitigate fluid overpressure events in the system in case of system failure, for example caused by blockages. A first example of a hydraulic fuse according to the present disclosure is shown in <FIG>. The hydraulic fuse <NUM> comprises a fuse body <NUM>, a first fuse element <NUM>, and a second fuse element <NUM>. The fuse body <NUM> defines a plenum <NUM>. The plenum <NUM> has an inlet <NUM> and an outlet <NUM>. The inlet <NUM> is configured to fluidly couple to a first fluid location <NUM>. The outlet <NUM> is configured to fluidly couple to a second fluid location <NUM>. The first fluid location <NUM> and the second fluid location <NUM> may be in fluid conduits which are part of the same fluid system or may be coupled to different sources of fluid. The second fluid location <NUM> may be in ambient conditions, and may, for example, contain or comprise fluid at atmospheric pressure. The first fluid location <NUM> contains fluid which is at a generally higher fluid pressure than in the second fluid location <NUM>. The plenum <NUM> may contain fluid at atmospheric pressure.

The first fuse element <NUM> is arranged to close the inlet <NUM>, such that fluid is prevented from entering the plenum <NUM> from the first fluid location <NUM>, via the inlet <NUM>. The second fuse element <NUM> is arranged to close the outlet <NUM>, such that fluid is prevented from flowing between the plenum <NUM> and the second fluid location <NUM>. The first fuse element <NUM> and the second fuse element <NUM> are integrally formed with the fuse body <NUM>. In particular, the first fuse element <NUM> is formed integrally with a wall of the fuse body <NUM> which faces the first fluid location <NUM>, and the second fuse element <NUM> is formed integrally with a wall of the fuse body <NUM> which faces the second fluid location <NUM>.

The first fuse element <NUM> and the second fuse element <NUM> are frangible, i.e., they are configured to be breakable. The first fuse element <NUM> and the second fuse element <NUM> may be configured to break in a brittle manner by bursting or shattering, or by breaking in a ductile manner by tearing. This may be enabled by varying the materials used for the first and second fuse elements or by varying the structure of the first and second fuse elements. The first fuse element <NUM> has a first thin wall section <NUM>, which forms a first weak point between the first fuse element <NUM> and the fuse body <NUM>, and the second fuse element <NUM> has a second thin wall section <NUM>, which forms a second weak point between the second fuse element <NUM> and the fuse body <NUM>. The first weak point and the second weak point form predetermined fracture points for the first and second fuse element <NUM>, <NUM>, respectively, such that the first fuse element <NUM> and the second fuse element <NUM> are designed to break at the first and second weak points, respectively. <FIG> shows an isometric view of the hydraulic fuse <NUM>, showing a side <NUM> of the hydraulic fuse <NUM> which faces the first fluid location <NUM>. The first thin wall section <NUM> extends around the perimeter of the portion of the first fuse element <NUM> which is formed as part of the wall of the fuse body <NUM>. In addition, the second thin wall section <NUM> extends around the perimeter of the portion of the second fuse element <NUM> which is formed as part of the wall of the fuse body <NUM>. The first thin wall section <NUM> is configured to break or burst when a fluid pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches or exceeds a first threshold pressure. The second thin wall section <NUM> is configured to break or burst when a fluid pressure differential between the plenum <NUM> and the second fluid location <NUM> reaches or exceeds a second threshold pressure. The first threshold pressure is higher than the second threshold pressure. In this context, breaking or bursting means that the first thin wall section <NUM> is broken to at least partially open the inlet <NUM> and allow fluid to flow from the first fluid location <NUM> to the plenum <NUM>, and the second thin wall section <NUM> is broken to at least partially open the outlet <NUM> and allow fluid to flow from the plenum <NUM> to the second fluid location <NUM>. The first thin wall section <NUM> and the second thin wall section <NUM> may be configured by any means to enable it to burst at or above the first threshold pressure and the second threshold pressure, respectively. For example, the thickness of the thin wall sections, the surface area of the thin wall sections, and/or the materials of the thin wall sections may be selected or varied to tune or design the thin wall sections to burst at or above the desired pressure thresholds. For example, the first thin wall section <NUM> may have a greater thickness than the second thin wall section <NUM> to enable it to burst at a higher pressure than the second thin wall section <NUM>.

The first fuse element <NUM> and the second fuse element <NUM> are contained within the volume defined by the fuse body <NUM>. As shown in <FIG>, the first fuse element <NUM> and the fuse body <NUM> together form a first smooth, substantially continuous surface <NUM> of the fuse body <NUM> which faces the first fluid location <NUM>. Here, the first fuse element <NUM> is formed integrally with the fuse body <NUM> to form the substantially continuous surface <NUM> which faces the first fluid location <NUM>. Similarly, the second fuse element <NUM> and the fuse body <NUM> together form a second smooth, substantially continuous surface <NUM> of the fuse body <NUM> which faces the second fluid location <NUM>. Here, the second fuse element <NUM> is formed integrally with the fuse body <NUM> to form the substantially continuous surface <NUM> which faces the first fluid location <NUM>. The substantially continuous surfaces <NUM>, <NUM> form substantially smooth fluid-washed surfaces which are exposed to fluid flow. The smooth surfaces ensure that there is negligible pressure loss created by the hydraulic fuse <NUM> when it is used in a fluid system.

<FIG> is a section view of the hydraulic fuse <NUM> through the plane marked A-A in <FIG>. The first fuse element <NUM> comprises a retention feature <NUM> which is configured to retain the first fuse element <NUM> within the plenum <NUM>. The retention feature <NUM> comprises a first dovetail-shaped portion <NUM> which is integrally formed with the portion of the first fuse element <NUM> which is arranged to close the inlet <NUM>. The width of the first dovetail-shaped portion <NUM> is greater than the width of the inlet <NUM>. After the first fuse element <NUM> is broken off the fuse body <NUM> when the first thin wall section <NUM> is broken, the first dovetail-shaped portion <NUM> prevents the first fuse element <NUM> from leaving the plenum <NUM> via the inlet <NUM>, thereby retaining the first fuse element <NUM> within the plenum <NUM>. Similarly, the second fuse element <NUM> also comprises a retention feature <NUM> which is configured to retain the second fuse element <NUM> within the plenum <NUM>. The retention feature <NUM> comprises a second dovetail-shaped portion <NUM> which is integrally formed with the portion of the second fuse element <NUM> which is arranged to close the outlet <NUM>. The width of the second dovetail-shaped portion <NUM> is greater than the width of the outlet <NUM>. After the second fuse element <NUM> is broken off the fuse body <NUM> when the second thin wall section <NUM> is broken, the second dovetail-shaped portion <NUM> prevents the second fuse element <NUM> from leaving the plenum <NUM> via the outlet <NUM>, thereby retaining the second fuse element <NUM> within the plenum <NUM>. In other examples, the retention feature <NUM>, <NUM> may be any feature which enables the first fuse element <NUM> and the second fuse element <NUM> to be retained within the plenum <NUM> when the first fuse element <NUM> and the second fuse element <NUM> are broken. For example, the retention feature may comprise a flexible member which enables the first fuse element <NUM> and the second fuse element to remain attached to the fuse body <NUM> even when the first fuse element <NUM> and the second fuse element <NUM> are broken. In other examples, the retention feature may comprise a connecting member between the first fuse element <NUM> and the second fuse element <NUM> which connects the first fuse element <NUM> and the second fuse element <NUM> together.

The hydraulic fuse <NUM> may be formed from an additive manufacturing process. The additive manufacturing process may be used to integrally form the fuse body <NUM>, the first fuse element <NUM>, and the second fuse element <NUM>. The additive manufacturing process may include a powder bed process, a material deposition process, or a 3D printing process. For example, the powder bed process may be a laser powder bed process. Alternatively, the hydraulic fuse <NUM> may be formed from a casting process. The hydraulic fuse <NUM> may be formed from any material suitable for the desired use. For example, the hydraulic fuse <NUM> may be formed from a metal.

In use, the hydraulic fuse <NUM> is arranged between the first fluid location <NUM> and the second fluid location <NUM>. In particular, the inlet <NUM> is coupled to the first fluid location <NUM> and the outlet is coupled to the second fluid location <NUM>. Generally, the first fluid location <NUM> will be at a higher fluid pressure than the second fluid location <NUM>. In normal operation, the hydraulic fuse <NUM> is in an inactive state, as shown in <FIG>. Fluid at the first fluid location <NUM> will flow past the first substantially continuous surface <NUM> of the hydraulic fuse <NUM> and fluid at the second fluid location <NUM> will flow past the second substantially continuous surface <NUM> of the hydraulic fuse <NUM>. In the inactive state, the first fuse element <NUM> closes the inlet <NUM> and the second fuse element <NUM> closes the outlet <NUM>, which prevents fluid flow into and through the plenum <NUM>. The fluid pressure in the plenum <NUM> may be at atmospheric pressure. During a fluid overpressure event, such as a blockage in one of the fluid locations, the pressure in the fluid locations may increase. The hydraulic fuse <NUM> is caused to move to an active state when the pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches the first threshold. When the pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches the first threshold, the first fuse element <NUM> is configured to break at the first thin wall section <NUM> and open the inlet <NUM>. Fluid from the first fluid location is consequently permitted to flow into the plenum <NUM>. The retention feature <NUM> of the first fuse element <NUM> retains the first fuse element within the plenum <NUM>. The plenum <NUM> now has a higher fluid pressure than in the inactive state due to the presence of the fluid from the first fluid location <NUM>. When the pressure differential between the plenum <NUM> and the second fluid location <NUM> reaches the second threshold, the second fuse element <NUM> is configured to break at the second thin wall section <NUM> and open the outlet <NUM>. Fluid is then permitted to flow from the plenum <NUM> to the second fluid location <NUM> through the outlet <NUM>. The overpressure event is thereby relieved by permitting fluid to flow from the first fluid location <NUM> to the second fluid location <NUM> via the hydraulic fuse <NUM>.

<FIG> shows a first example of a hydraulic manifold <NUM> according to the present disclosure. The hydraulic manifold <NUM> comprises a first fluid conduit <NUM> and a second fluid conduit <NUM>. The first fluid conduit <NUM> and the second fluid conduit <NUM> are divided or separated by a manifold wall <NUM>. The first fluid conduit <NUM> defines a first fluid location <NUM> and the second fluid conduit <NUM> defines a second fluid location <NUM>. The first fluid conduit <NUM> is larger than the second fluid conduit <NUM>. The first fluid conduit <NUM> is configured to carry fluid at a higher pressure than the second fluid conduit <NUM>. The hydraulic manifold <NUM> also comprises a hydraulic fuse <NUM>. The hydraulic fuse <NUM> is disposed in the manifold wall <NUM>. In particular, the hydraulic fuse <NUM> is integrally formed with the manifold wall <NUM> such that a fuse body of the hydraulic fuse <NUM> is formed by the manifold wall <NUM>. The hydraulic fuse <NUM> comprises a plenum <NUM> formed in the manifold wall <NUM>, a first fuse element <NUM>, and a second fuse element <NUM>. The plenum <NUM> has an inlet <NUM> and an outlet <NUM>. The inlet <NUM> is configured to fluidly couple to the first fluid location <NUM> in the first fluid conduit <NUM>. The outlet <NUM> is configured to fluidly couple to the second fluid location <NUM> in the second fluid conduit <NUM>.

The first fuse element <NUM> is arranged to close the inlet <NUM>, such that fluid is prevented from entering the plenum <NUM> from the first fluid location <NUM>, via the inlet <NUM>. The second fuse element <NUM> is arranged to close the outlet <NUM>, such that fluid is prevented from flowing between the plenum <NUM> and the second fluid location <NUM>. The first fuse element <NUM> and the second fuse element <NUM> are integrally formed with the manifold wall <NUM>. In particular, the first fuse element <NUM> is formed integrally with a portion of the manifold wall <NUM> which faces the first fluid location <NUM>, and the second fuse element <NUM> is formed integrally with a portion of the manifold wall <NUM> which faces the second fluid location <NUM>.

The first fuse element <NUM> and the second fuse element <NUM> are frangible, i.e., they are configured to be breakable. The first fuse element <NUM> and the second fuse element <NUM> may be configured to break in a brittle manner by bursting or shattering, or by breaking in a ductile manner by tearing. This may be enabled by varying the materials used for the first and second fuse elements or by varying the structure of the first and second fuse elements. The first fuse element <NUM> has a first thin wall section <NUM>, which forms a first weak point between the first fuse element <NUM> and the manifold wall <NUM>, and the second fuse element <NUM> has a second thin wall section <NUM>, which forms a second weak point between the second fuse element <NUM> and the manifold wall <NUM>. The first weak point and the second weak point form predetermined fracture points for the first and second fuse element <NUM>, <NUM>, respectively, such that the first fuse element <NUM> and the second fuse element <NUM> are designed to break at the first and second weak points, respectively.

<FIG> shows an isometric view of the hydraulic manifold <NUM>. The first thin wall section <NUM> extends around the perimeter of the portion of the first fuse element <NUM> which is formed as part of the manifold wall <NUM>. Similarly, the second thin wall section <NUM> extends around the perimeter of the portion of the second fuse element <NUM> which is formed as part of the manifold wall <NUM>. The first thin wall section <NUM> is configured to break or burst when a fluid pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches or exceeds a first threshold pressure. The second thin wall section <NUM> is configured to break or burst when a fluid pressure differential between the plenum <NUM> and the second fluid location <NUM> reaches or exceeds a second threshold pressure. The first threshold pressure is higher than the second threshold pressure. In this context, breaking or bursting means that the first thin wall section <NUM> is broken to at least partially open the inlet <NUM> and allow fluid to flow from the first fluid location <NUM> in the first fluid conduit <NUM> to the plenum <NUM>, and the second thin wall section <NUM> is broken to at least partially open the outlet <NUM> and allow fluid to flow from the plenum <NUM> to the second fluid location <NUM> in the second fluid conduit <NUM>. The first thin wall section <NUM> and the second thin wall section <NUM> may be configured by any means to enable it to burst above the first threshold pressure and the second threshold pressure, respectively. For example, the thickness of the thin wall sections, the surface area of the thin wall sections, and/or the materials of the thin wall sections may be selected or varied to tune or design the thin wall sections to burst at or above the desired pressure levels. For example, the first thin wall section <NUM> may have a greater thickness than the second thin wall section <NUM> to enable it to burst at a higher pressure than the second thin wall section <NUM>.

The first fuse element <NUM> and the second fuse element <NUM> are contained within the volume circumscribed by the manifold wall <NUM>. As shown in <FIG>, the first fuse element <NUM> and the manifold wall <NUM> together form a first smooth, substantially continuous surface <NUM> of the manifold wall <NUM> which faces the first fluid location <NUM>. Here, the first fuse element <NUM> is formed integrally with the manifold wall <NUM> to form the substantially continuous surface <NUM> which faces the first fluid location <NUM>. Similarly, the second fuse element <NUM> and the manifold wall <NUM> together form a second smooth, substantially continuous surface <NUM> of the manifold wall <NUM> which faces the second fluid location <NUM>. Here, the second fuse element <NUM> is formed integrally with the manifold wall <NUM> to form the substantially continuous surface <NUM> which faces the first fluid location <NUM>. The first and second substantially continuous surfaces <NUM>, <NUM> form substantially smooth fluid-washed surfaces which are exposed to fluid flow through the first and second fluid conduits <NUM>, <NUM>, respectively. The smooth surfaces ensure that there is negligible pressure loss created by the presence of the hydraulic fuse <NUM> in the hydraulic manifold <NUM>.

The first fuse element <NUM> comprises a retention feature <NUM> which is configured to retain the first fuse element <NUM> within the plenum <NUM>. The retention feature <NUM> comprises a first dovetail-shaped portion <NUM> which is integrally formed with the portion of the first fuse element <NUM> which is arranged to close the inlet <NUM>. The width of the first dovetail-shaped portion <NUM> is greater than the width of the inlet <NUM>. After the first fuse element <NUM> is broken off the manifold wall <NUM> when the first thin wall section <NUM> is broken, the first dovetail-shaped portion <NUM> prevents the first fuse element <NUM> from leaving the plenum <NUM> via the inlet <NUM>, thereby retaining the first fuse element <NUM> within the plenum <NUM>.

Similarly, the second fuse element <NUM> also comprises a retention feature <NUM> which is configured to retain the second fuse element <NUM> within the plenum <NUM>. The retention feature <NUM> comprises a second dovetail-shaped portion <NUM> which is integrally formed with the portion of the second fuse element <NUM> which is arranged to close the outlet <NUM>. The width of the second dovetail-shaped portion <NUM> is greater than the width of the outlet <NUM>. After the second fuse element <NUM> is broken off the manifold wall <NUM> when the second thin wall section <NUM> is broken, the second dovetail-shaped portion <NUM> prevents the second fuse element <NUM> from leaving the plenum <NUM> via the outlet <NUM>, thereby retaining the second fuse element <NUM> within the plenum <NUM>. In other examples, the retention feature <NUM>, <NUM> may be any feature which enables the first fuse element <NUM> and the second fuse element <NUM> to be retained within the plenum <NUM> when the first fuse element <NUM> and the second fuse element <NUM> are broken from the manifold wall <NUM>. For example, the retention feature may comprise a flexible member which enables the first fuse element <NUM> and the second fuse element <NUM> to remain attached to the fuse body <NUM> even when the first fuse element <NUM> and the second fuse element <NUM> are broken from the manifold wall <NUM>. In other examples, the retention feature may comprise a connecting member between the first fuse element <NUM> and the second fuse element <NUM> which connects the first fuse element <NUM> and the second fuse element <NUM> together.

The hydraulic manifold <NUM> may be formed from an additive manufacturing process. The additive manufacturing process may be used to integrally form the first fluid conduit <NUM>, the hydraulic fuse <NUM>, and the second fluid conduit <NUM>. The additive manufacturing process may include a powder bed process, a material deposition process, or a 3D printing process. For example, the powder bed process may be a laser powder bed process. Alternatively, the hydraulic manifold <NUM> may be formed from a casting process. The hydraulic manifold <NUM> may be formed from any material suitable for the desired use. For example, the hydraulic manifold <NUM> may be formed from a metal.

The hydraulic manifold <NUM> further comprises an extraction hole <NUM> disposed in the manifold wall <NUM>. The extraction hole <NUM> is fluidly coupled with the plenum <NUM> and enables any material which is present in the plenum <NUM> to be extracted. For example, debris or powder from the manufacturing process may be present in the plenum <NUM> and will need to be removed before use. The extraction hole <NUM> is sealed by a sealing element <NUM>. The sealing element <NUM> may be a fastener, such as a screw.

In use, fluid flows through the first fluid conduit <NUM> and the second fluid conduit <NUM>. Fluid in the first fluid conduit <NUM> will be at a higher fluid pressure than fluid in the second fluid conduit <NUM>. In normal operation, the hydraulic fuse <NUM> is in an inactive state, as shown in <FIG>. Fluid in the first fluid conduit <NUM> will flow past the first substantially continuous surface <NUM> of the manifold wall <NUM> and fluid in the second fluid conduit <NUM> will flow past the second substantially continuous surface <NUM> of the manifold wall <NUM>. In the inactive state, the first fuse element <NUM> closes the inlet <NUM> and the second fuse element <NUM> closes the outlet <NUM>, which prevents fluid flow into and through the plenum <NUM>. The fluid pressure in the plenum <NUM> may be at atmospheric pressure. During a fluid overpressure event, such as a blockage in the first fluid conduit <NUM>, the pressure at the first fluid location <NUM> may increase. The hydraulic fuse <NUM> is caused to move to an active state when the pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches the first threshold. When the pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches the first threshold, the first fuse element <NUM> is configured to break at the first thin wall section <NUM> and open the inlet <NUM>. Fluid from the first fluid location <NUM> in the first fluid conduit <NUM> is consequently permitted to flow into the plenum <NUM>. The retention feature <NUM> of the first fuse element <NUM> retains the first fuse element <NUM> within the plenum <NUM>. The plenum <NUM> now has a higher fluid pressure than in the inactive state due to the presence of the fluid from the first fluid location <NUM>. When the pressure differential between the plenum <NUM> and the second fluid location <NUM> reaches the second threshold, the second fuse element <NUM> is configured to break at the second thin wall section <NUM> and open the outlet <NUM>. The retention feature <NUM> of the second fuse element <NUM> retains the second fuse element <NUM> within the plenum <NUM>. Fluid is then permitted to flow from the plenum <NUM> to the second fluid location <NUM> in the second fluid conduit <NUM> through the outlet <NUM>. The overpressure event is thereby relieved by permitting fluid to flow from the first fluid location <NUM> in the first fluid conduit <NUM> to the second fluid location <NUM> in the second fluid conduit <NUM> via the hydraulic fuse <NUM>.

<FIG> shows a second example of a hydraulic manifold <NUM> according to the present disclosure. The second example hydraulic manifold <NUM> comprises a fluid conduit <NUM> and a hydraulic fuse <NUM>. The hydraulic fuse <NUM> is substantially similar to the hydraulic fuse <NUM> described with reference to <FIG>, with like reference numerals denoting like features.

The fluid conduit <NUM> carries a flow of a fluid therethrough. The fluid conduit <NUM> comprises a manifold wall <NUM> which defines a first fluid location <NUM>. The hydraulic fuse <NUM> is attached to the manifold wall <NUM> such that the inlet <NUM> of the hydraulic fuse <NUM> is configured to fluidly couple to the first fluid location <NUM> in the fluid conduit <NUM>. The outlet <NUM> of the hydraulic fuse <NUM> is configured to fluidly couple to ambient conditions, for example to an environment around the hydraulic manifold <NUM>. The ambient conditions therefore form the second fluid location <NUM>. The hydraulic fuse <NUM> may be attached to the manifold wall <NUM> using any suitable fasteners. In other examples, the hydraulic fuse <NUM> may be integrally formed with the manifold wall <NUM>.

The hydraulic fuse <NUM> comprises a first fuse element <NUM> and a second fuse element <NUM>, as described with reference to <FIG>. The first fuse element <NUM> is arranged to close the inlet <NUM>, such that fluid is prevented from entering the plenum <NUM> from the first fluid location <NUM> in the fluid conduit <NUM>, via the inlet <NUM>. The second fuse element <NUM> is arranged to close the outlet <NUM>, such that fluid is prevented from flowing between the plenum <NUM> and the second fluid location <NUM>. The first fuse element <NUM> and the second fuse element <NUM> are integrally formed with the fuse body <NUM>. In particular, the first fuse element <NUM> is formed integrally with a wall of the fuse body <NUM> which faces the first fluid location <NUM>, and the second fuse element <NUM> is formed integrally with a wall of the fuse body <NUM> which faces the second fluid location <NUM>. The first and second fuse elements <NUM>, <NUM> are frangible, as described previously. The first fuse element <NUM> and the fuse body <NUM> together form a first smooth, substantially continuous surface <NUM> of the fuse body <NUM> which faces the first fluid location <NUM>. Here, the first fuse element <NUM> is formed integrally with the fuse body <NUM> to form the substantially continuous surface <NUM> which faces the first fluid location <NUM>. Similarly, the second fuse element <NUM> and the fuse body <NUM> together form a second smooth, substantially continuous surface <NUM> of the fuse body <NUM> which faces the second fluid location <NUM>. Here, the second fuse element <NUM> is formed integrally with the fuse body <NUM> to form the substantially continuous surface <NUM> which faces the first fluid location <NUM>. The substantially continuous surfaces <NUM>, <NUM> form substantially smooth fluid-washed surfaces which are exposed to fluid flow.

In normal operation, the hydraulic fuse <NUM> is in an inactive state, as shown in <FIG>. Fluid flows through the fluid conduit <NUM> and past the first substantially continuous surface <NUM> of the hydraulic fuse <NUM>. In the inactive state, the first fuse element <NUM> closes the inlet <NUM> and the second fuse element <NUM> closes the outlet <NUM>, which prevents fluid flow into and through the plenum <NUM>. The fluid pressure in the plenum <NUM> may be at atmospheric pressure. During a fluid overpressure event, such as a blockage in the fluid conduit <NUM>, the pressure in the first fluid location <NUM> may increase. The hydraulic fuse <NUM> is caused to move to an active state when the pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches the first threshold. When the pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches the first threshold, the first fuse element <NUM> is configured to break at the first thin wall section <NUM> and open the inlet <NUM>. Fluid from the first fluid location <NUM> is consequently permitted to flow into the plenum <NUM>. The retention feature <NUM> of the first fuse element <NUM> retains the first fuse element within the plenum <NUM>. The plenum <NUM> now has a higher fluid pressure than in the inactive state due to the presence of the fluid from the first fluid location <NUM>. When the pressure differential between the plenum <NUM> and the second fluid location <NUM> reaches the second threshold, the second fuse element <NUM> is configured to break at the second thin wall section <NUM> and open the outlet <NUM>. The second threshold will be quickly reached as the second fluid location <NUM> is at atmospheric pressure. Therefore, the second fuse element <NUM> will be broken soon after the first fuse element <NUM> is broken. Fluid is then permitted to flow from the plenum <NUM> to the second fluid location <NUM> through the outlet <NUM>, with the second fluid location <NUM> being in the ambient surroundings. The overpressure event is thereby relieved by permitting fluid to flow from the first fluid location <NUM> to the second fluid location <NUM> via the hydraulic fuse <NUM>. The hydraulic fuse <NUM> therefore functions as a pressure relief device which vents to atmospheric pressure in the case of an overpressure event or a pressure surge in the fluid conduit <NUM>.

<FIG> shows a third example of a hydraulic manifold according to the present disclosure. The third example hydraulic manifold is substantially similar to the first example hydraulic manifold described with reference to <FIG>, with like reference numerals denoting like features. The third example hydraulic manifold differs with respect to the first and second fuse elements.

The hydraulic manifold <NUM> comprises a first fluid conduit <NUM> and a second fluid conduit <NUM>. The first fluid conduit <NUM> and the second fluid conduit <NUM> are divided or separated by a manifold wall <NUM>. The first fluid conduit <NUM> defines a first fluid location <NUM> and the second fluid conduit <NUM> defines a second fluid location <NUM>. The first fluid conduit <NUM> is larger than the second fluid conduit <NUM>. The first fluid conduit <NUM> is configured to carry fluid at a higher pressure than the second fluid conduit <NUM>. The hydraulic manifold <NUM> also comprises a hydraulic fuse <NUM>. The hydraulic fuse <NUM> is disposed in the manifold wall <NUM>. In particular, the hydraulic fuse <NUM> is integrally formed with the manifold wall <NUM> such that a fuse body of the hydraulic fuse <NUM> is formed by the manifold wall <NUM>. The hydraulic fuse <NUM> comprises a plenum <NUM> formed in the manifold wall <NUM>, a first fuse element <NUM>, and a second fuse element <NUM>. The plenum <NUM> has an inlet <NUM> and an outlet <NUM>. The inlet <NUM> is configured to fluidly couple to the first fluid location <NUM> in the first fluid conduit <NUM>. The outlet <NUM> is configured to fluidly couple to the second fluid location <NUM> in the second fluid conduit <NUM>.

The first fuse element <NUM> and the second fuse element <NUM> are configured to fracture away from the manifold wall <NUM>. In particular, the first fuse element <NUM> and the second fuse element <NUM> are configured to tear away from the manifold wall <NUM>. The thickness of the first fuse element <NUM> is tapered to a thinnest point at a bottom edge <NUM> of the first fuse element <NUM>. Similarly, the thickness of the second fuse element <NUM> is tapered to a thinnest point at a bottom edge <NUM> of the second fuse element <NUM>. By being the thinnest points of the manifold wall <NUM>, the bottom edge <NUM> of the first fuse element <NUM> forms a first weak point between the first fuse element <NUM> and the manifold wall <NUM>, and the bottom edge <NUM> of the second fuse element <NUM> forms a second weak point between the second fuse element <NUM> and the manifold wall <NUM>. The first weak point and the second weak point form predetermined fracture points for the first and second fuse element <NUM>, <NUM>, respectively, such that the first fuse element <NUM> and the second fuse element <NUM> are designed to fracture at the first and second weak points, respectively. The bottom edge <NUM> of the first fuse element <NUM> is configured to fracture when a fluid pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches a first threshold pressure. The bottom edge <NUM> of the second fuse element <NUM> is configured to fracture when a fluid pressure differential between the plenum <NUM> and the second fluid location <NUM> reaches a second threshold pressure. The first threshold pressure is higher than the second threshold pressure. The first fuse element <NUM> and the second fuse element <NUM> are formed from ductile materials, such as aluminium, such that the first fuse element <NUM> is configured to fracture at its bottom edge <NUM> in a ductile manner, and the second fuse element <NUM> is configured to fracture at its bottom edge <NUM> in a ductile manner. This means that the first fuse element <NUM> is configured to tear at its bottom edge <NUM> when the fluid pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches the first threshold pressure, thus at least partially opening the inlet <NUM> and allowing fluid to flow from the first fluid location <NUM> to the plenum <NUM>. The second fuse element <NUM> is also configured to tear at its bottom edge <NUM> when the fluid pressure differential between the plenum <NUM> and the second fluid location <NUM> reaches the second threshold pressure, thus at least partially opening the outlet <NUM> and allowing fluid to flow from the plenum <NUM> to the second fluid location <NUM>. The thickness of the manifold wall at the bottom edges, the length of the bottom edges, the surface area of the fuse elements, and/or the materials of the fuse elements may be selected or varied to tune or design the bottom edges to fracture at or above the desired pressure thresholds. For example, the bottom edge <NUM> of the first fuse element <NUM> may have a greater thickness than the bottom edge <NUM> of the second fuse element <NUM> to enable it to fracture at a higher pressure than the bottom edge <NUM> of the first fuse element <NUM>. In other examples, the first weak point and the second weak point may be formed by other edges or points of the first fuse element and the second fuse element, respectively.

The first fuse element <NUM> and the second fuse element <NUM> are contained within the volume circumscribed by the manifold wall <NUM>. The first fuse element <NUM> and the manifold wall <NUM> together form a first smooth, substantially continuous surface <NUM> of the manifold wall <NUM> which faces the first fluid location <NUM>. In particular, the first fuse element <NUM> is formed integrally with the manifold wall <NUM> to form the substantially continuous surface <NUM> which faces the first fluid location <NUM>. Similarly, the second fuse element <NUM> and the manifold wall <NUM> together form a second smooth, substantially continuous surface <NUM> of the manifold wall <NUM> which faces the second fluid location <NUM>. Here, the second fuse element <NUM> is formed integrally with the manifold wall <NUM> to form the substantially continuous surface <NUM> which faces the first fluid location <NUM>. The first and second substantially continuous surfaces <NUM>, <NUM> form substantially smooth fluid-washed surfaces which are exposed to fluid flow through the first and second fluid conduits <NUM>, <NUM>, respectively. The smooth surfaces ensure that there is negligible pressure loss created by the presence of the hydraulic fuse <NUM> in the hydraulic manifold <NUM>.

The first fuse element <NUM> comprises a retention feature <NUM> which is configured to retain the first fuse element <NUM> within the plenum <NUM>. The retention feature <NUM> comprises a first series of ridges <NUM> which are integrally formed on an inner surface of the manifold wall <NUM> and the first fuse element <NUM>, the inner surface facing the plenum <NUM>. Each of the first series of ridges <NUM> extends substantially vertically across the manifold wall <NUM> and the first fuse element <NUM>. The first series of ridges <NUM> provide a degree of flexibility to the manifold wall <NUM> and the first fuse element <NUM>, so that the first fuse element <NUM> is flexibly attached to the manifold wall <NUM>. The first series of ridges <NUM> therefore enable the manifold wall <NUM> and the first fuse element <NUM> to bend together when the bottom edge <NUM> of the first fuse element <NUM> is torn. This ensures that the first fuse element <NUM> remains attached to the manifold wall <NUM> even when the bottom edge <NUM> is torn, thereby retaining the first fuse element within the plenum <NUM> and preventing it from entering the first fluid conduit <NUM>. Similarly, the second fuse element <NUM> also comprises a retention feature <NUM> which is configured to retain the second fuse element <NUM> within the plenum <NUM>. The retention feature <NUM> comprises a second series of ridges <NUM> which are integrally formed on an inner surface of the manifold wall <NUM> and the second fuse element <NUM>, the inner surface facing the plenum <NUM>. Each of the second series of ridges <NUM> extends substantially vertically across the manifold wall <NUM> and the first fuse element <NUM>. The second series of ridges <NUM> provide a degree of flexibility to the manifold wall <NUM> and the second fuse element <NUM> so that the second fuse element <NUM> is flexibly attached to the manifold wall <NUM>. The second series of ridges <NUM> therefore enable the manifold wall <NUM> and the second fuse element <NUM> to bend together when the bottom edge <NUM> of the second fuse element <NUM> is torn. This ensures that the second fuse element <NUM> remains attached to the manifold wall <NUM> even when the bottom edge <NUM> is torn, thereby retaining the second fuse element within the plenum <NUM> and preventing it from entering the second fluid conduit <NUM>. In other examples, the retention feature may be any feature which enables the first fuse element <NUM> and the second fuse element <NUM> to be retained within the plenum <NUM> when the first fuse element <NUM> and the second fuse element <NUM> are fractured away from the manifold wall <NUM>. In other examples, one of the first fuse element and the second fuse element may be flexibly attached to the manifold wall, as described above, and the other of the first fuse element and the second fuse element may be rigidly attached to or formed with the manifold wall, for example as described with reference to <FIG>.

The hydraulic manifold <NUM> may be formed from an additive manufacturing process. The additive manufacturing process may be used to integrally form the first fluid conduit <NUM>, the hydraulic fuse <NUM>, and the second fluid conduit <NUM>. The additive manufacturing process may include a powder bed process, a material deposition process, or a 3D printing process. For example, the powder bed process may be a laser powder bed process. The hydraulic manifold <NUM> may be formed from any material suitable for the desired use. For example, the hydraulic manifold <NUM> may be formed from a ductile material, such as aluminium.

In use, fluid flows through the first fluid conduit <NUM> and the second fluid conduit <NUM>. Fluid in the first fluid conduit <NUM> will be at a higher fluid pressure than fluid in the second fluid conduit <NUM>. In normal operation, the hydraulic fuse <NUM> is in an inactive state, as shown in <FIG>. Fluid in the first fluid conduit <NUM> will flow past the first substantially continuous surface <NUM> of the manifold wall <NUM> and fluid in the second fluid conduit <NUM> will flow past the second substantially continuous surface <NUM> of the manifold wall <NUM>. In the inactive state, the first fuse element <NUM> closes the inlet <NUM> and the second fuse element <NUM> closes the outlet <NUM>, which prevents fluid flow into and through the plenum <NUM>. The fluid pressure in the plenum <NUM> may be at atmospheric pressure. During a fluid overpressure event, such as a blockage in the first fluid conduit <NUM>, the pressure at the first fluid location <NUM> may increase. The hydraulic fuse <NUM> is caused to move to an active state when the pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches the first threshold. When the pressure differential between the first fluid location <NUM> and the plenum <NUM> reaches the first threshold, the first fuse element <NUM> is configured to tear at its bottom edge <NUM> and open the inlet <NUM>. Fluid from the first fluid location <NUM> in the first fluid conduit <NUM> is consequently permitted to flow into the plenum <NUM>. The retention feature <NUM> of the first fuse element <NUM> retains the first fuse element <NUM> within the plenum <NUM>, as the first fuse element <NUM> and the manifold wall <NUM> bend together due to the presence of the ridges <NUM>. The plenum <NUM> now has a higher fluid pressure than in the inactive state due to the presence of the fluid from the first fluid location <NUM>. When the pressure differential between the plenum <NUM> and the second fluid location <NUM> reaches the second threshold, the second fuse element <NUM> is configured to tear at its bottom edge <NUM> and open the outlet <NUM>. The retention feature <NUM> of the second fuse element <NUM> retains the second fuse element <NUM> within the plenum <NUM>, as the second fuse element <NUM> and the manifold wall <NUM> bend together due to the presence of the ridges <NUM>. Fluid is then permitted to flow from the plenum <NUM> to the second fluid location <NUM> in the second fluid conduit <NUM> through the outlet <NUM>. The overpressure event is thereby relieved by permitting fluid to flow from the first fluid location <NUM> in the first fluid conduit <NUM> to the second fluid location <NUM> in the second fluid conduit <NUM> via the hydraulic fuse <NUM>.

The hydraulic fuse and the hydraulic manifold of the present disclosure provide improved reliability of activation of the fuse. By having a plenum between the first fluid location and the second fluid location, the first fluid location is isolated from the second fluid location, so that the hydraulic fuse can operate independently of any transient or dynamic pressure differential between the first fluid location and the second fluid location. The hydraulic fuse provides a first fuse element between the first fluid location and the plenum and a second fuse element between the plenum and the second fluid location, when enables the hydraulic fuse to be activated when the pressure differential between the first fluid location and the plenum exceeds a designed threshold pressure. The activation of the hydraulic fuse is therefore not affected by variations in pressure at the second fluid location relative to the first fluid location. This ensures that the hydraulic fuse is able to reliably activate at the designed threshold pressure. The structure of the hydraulic fuse has low complexity and reduced mass compared to known hydraulic fuses. The hydraulic fuse can be readily tuned to the desired pressure thresholds required in use, by adapting the first and second fuse elements. The hydraulic fuse also presents smooth, continuous surfaces to the fluid flow at the first and second fluid locations, thereby minimising pressure loss due to the presence of the hydraulic fuse in a fluid system or a hydraulic manifold. The retention features ensure that the first and second fuse elements are retained within the plenum even after the fuse has been activated, reducing the risk of debris entering other parts of the hydraulic manifold or fluid system and causing blockages. The hydraulic fuse and the hydraulic manifold can be manufactured integrally with each other, which enables the hydraulic fuse to be easily embedded within the hydraulic manifold in a simple and compact manner. The hydraulic fuse and the hydraulic manifold can be manufactured using an additive manufacturing process, which reduces manufacturing time and enables the hydraulic fuse to be located in optimal locations in the hydraulic manifold.

Although it has been described in the above examples that the first fuse element and the second fuse element are configured to be frangible or breakable, in other examples, the first fuse element and the second fuse element may be otherwise configured to move to open the inlet and the outlet, respectively, without breaking. For example, each of the first and second fuse elements may have respective opening mechanisms that allow the inlet to be opened when the pressure differential between the first fluid location and the plenum exceeds the first threshold and allow the outlet to be opened when the pressure differential between the plenum and the second fluid location exceeds the second threshold. In further examples, one of the first fuse element and the second fuse element may be frangible, and the other of the first fuse element and the second fuse element may not be frangible and may be otherwise configured to open the inlet or the outlet.

The opening mechanisms may also be reversible, in that the first fuse element may be configured to re-close the inlet when the pressure differential between the first fluid location and the plenum falls below the first threshold and that the second fuse element may be configured to re-close the outlet when the pressure differential between the plenum and the second fluid location falls below the second threshold. In this way, the hydraulic fuse may be reusable.

Although it has been described in the above examples that the first and second fuse elements are integrally formed with the fuse body or the manifold wall, in other examples, the first and second fuse elements may be otherwise arranged with respect to the fuse body or manifold wall. For example, the first and second fuse elements may be attached to the fuse body or manifold wall.

Although it has been described in the above examples that the first and second fuse elements are configured to fracture at predetermined weak points or predetermined fracture points, in other examples, the first and second fuse elements may be configured to fracture at one or more points which are not predetermined. For instance, the first or second fuse elements may have multiple weak points and the fuse element may fracture at any of these points, without it being predetermined that the fuse element will fracture at a specific one of these points.

Claim 1:
A gas turbine engine (<NUM>) comprising a hydraulic fuse (<NUM>, <NUM>, <NUM>), the hydraulic fuse comprising:
a fuse body (<NUM>) defining a plenum (<NUM>, <NUM>, <NUM>), the plenum comprising:
an inlet (<NUM>) configured to couple to a first fluid location (<NUM>, <NUM>, <NUM>); and
an outlet (<NUM>) configured to couple to a second fluid location (<NUM>, <NUM>, <NUM>);
a first fuse element (<NUM>, <NUM>, <NUM>) arranged to close the inlet, the first fuse element configured to open the inlet when a pressure differential between the first fluid location and the plenum reaches a first threshold;
a second fuse element (<NUM>, <NUM>, <NUM>) arranged to close the outlet, the second fuse element configured to open the outlet when a pressure differential between the plenum and the second fluid location reaches a second threshold, wherein the first threshold is higher than the second threshold;
wherein in an inactive state, the inlet is closed by the first fuse element and the outlet is closed by the second fuse element to prevent fluid flow through the plenum; and
wherein in an active state, the pressure differential between the first fluid location and the plenum reaches the first threshold to cause the first fuse element to open and permit fluid flow through the inlet, and the pressure differential between the plenum and the second fluid location reaches the second threshold to cause the second fuse element to open and permit fluid flow through the outlet.