Fuel system, kit of parts, aircraft and method for manufacturing an aircraft

Abstract

The present invention relates to fuel systems, kits, aircraft, and methods for manufacturing aircraft. A fuel system for an aircraft is provided, the fuel system comprising a fuel tank for storing fuel during operation of the aircraft and a diffuser disposed inside the fuel tank. The diffuser is configured such that the diffuser forms part of a flow path configured to connect a fuel source to an interior of the fuel tank. The diffuser comprises a wall at least partially defining an interior space of the diffuser, an opening in the wall providing access to the interior space, and a blocking component configured to block the opening.

Description

TECHNICAL FIELD

[0001] The present invention relates to a fuel system for an aircraft, a kit of parts for forming a fuel system, an aircraft comprising a fuel system and a method for manufacturing an aircraft. BACKGROUND

[0002] Fuel storage tanks typically have a diffuser fitted to an inlet through which fuel is delivered into the tank. The function of the diffuser is to reduce the velocity of the fuel entering the tank during filling, which in turn reduces static electricity build-up, reduces the generation of fuel vapour and also reduces the effects of cavitation. As a result, the flammability of the fuel tank is reduced compared to the case where no diffuser is provided.

[0003] For aircraft applications, it is desirable to pressure test the fuel delivery pipework system connecting a fuel source to the inlet after the fuel delivery pipework system has been fully assembled and connected to the inlet. The diffuser provided above the inlet adds difficulty in accessing the inlet in order to block the inlet to enable such pressure testing. Conventionally, in order to test the pipework system immediately upstream of the tank inlet, the diffuser must be removed and then refitted after testing, which significantly increases the time of the assembly process. SUMMARY

[0004] A first aspect of the present invention provides a fuel system for an aircraft. The fuel system comprises a fuel tank for storing fuel during operation of the aircraft and a diffuser provided inside the fuel tank. The diffuser is configured such that the diffuser forms part of a flow path configured to connect a fuel source to an interior of the fuel tank. The diffuser comprises a wall at least partially defining an interior space of the diffuser, an opening in the wall providing access to the interior space, and a blocking component configured to block the opening.

[0005] Optionally, the blocking component is removably engaged with the wall.

[0006] Optionally, the fuel system further comprises a locking member configured to engage with the blocking component and the wall to prevent the blocking component from disengaging from the wall.

[0007] Optionally, the blocking component and the wall each comprise interlocking features configured to interlock to retain the blocking component on the wall.

[0008] Optionally, the fuel system further comprises a sealing element located between the blocking component and the wall, the sealing element being configured to prevent fuel flow through the opening.

[0009] Optionally, the opening is configured to engage with at least two different types of blocking component.

[0010] Optionally, the fuel system further comprises a fuel delivery device forming a further part of the flow path. A first end of the fuel delivery device is connectable to the fuel source and a second end of the fuel delivery device is connected to the diffuser.

[0011] Optionally, the fuel tank is formed from a structural component of the aircraft.

[0012] Optionally, the fuel tank is formed from a wing box of the aircraft.

[0013] Optionally, the blocking member is a test blocking component and is configured to block the flow path to prevent fuel from flowing into the fuel tank.

[0014] Optionally, the diffuser comprises an outlet through which fuel flows into an interior space of the diffuser during delivery of fuel into the fuel tank, and the test blocking component comprises a sealing member configured to block the outlet.

[0015] Optionally, the sealing member is configured to form a pressure-tight seal against the outlet.

[0016] Optionally, the test blocking component comprises a port configured to be engageable with a pressure testing device such that the pressure testing device is able to measure a pressure in the flow path upstream of the test blocking component when engaged with the port.

[0017] Optionally, the blocking component is an operational blocking component and is configured to allow fuel to flow from the fuel source into the fuel tank through the diffuser when the operational blocking component is engaged with the opening.

[0018] A second aspect of the application provides a kit of parts. The kit of parts comprises a fuel tank, a diffuser, a test blocking component and an operational blocking component. The fuel tank has an inlet through which fuel can flow into the fuel tank. The diffuser is disposed within the fuel tank, the diffuser is connected to the inlet and the diffuser comprises a wall defining an opening and configured to be engageable with a blocking component. The test blocking component is configured to engage with the wall to block the opening and is configured to prevent fuel from flowing from a fuel source connected to the inlet into the fuel tank when the test blocking component is engaged with the wall. The operational blocking component is configured to engage with the wall to block the opening and is configured to allow fuel to flow from a fuel source connected to the inlet into the fuel tank when the operational blocking component is engaged with the opening.

[0019] Optionally, the kit of parts further comprises a locking component configured to engage with the operational blocking component and the wall when the operational blocking component is engaged with the wall such that the operational blocking component is prevented from disengaging from the wall.

[0020] Optionally, the kit of parts is configured to form, when assembled, a fuel system according to the first aspect.

[0021] A third aspect of the present invention provides an aircraft comprising a fuel system according to the first aspect when the blocking component is an operational blocking component.

[0022] A fourth aspect of the present invention provides a method for manufacturing an aircraft, the method comprising:

[0023] providing a fuel tank component configured to form at least part of a fuel tank of an aircraft connected to a fuel delivery apparatus configured to define a flow path between a fuel source and an interior of the fuel tank and comprising a diffuser configured to be disposed within the fuel tank;

[0024] arranging a test blocking component on the diffuser such that the test blocking component blocks the flow path and prevents fluid flow between an interior space of the fuel delivery apparatus and the interior of the fuel tank.

[0025] performing a pressure test on the fuel delivery apparatus;

[0026] replacing the test blocking component with an operational blocking component that allows fluid flow between the interior space of the fuel delivery apparatus and the interior of the fuel tank.

[0027] Optionally, the method further comprises, after replacing the test blocking component with the operational blocking component, assembling the fuel tank component into the fuel tank. BRIEF DESCRIPTION OF DRAWINGS

[0028] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0029] Figure 1a is a cross-section through an example fuel system according to the present invention;

[0030] Figure 1b is a schematic cross-section through a diffuser of the example fuel system of Figure 1a including an example test blocking component;

[0031] Figure 1c is a schematic cross-section through a diffuser of the example fuel system of Figure 1a including an example operational blocking component;

[0032] Figure 2a is a schematic cross-section through an example test blocking component engaged with a wall of an example diffuser according to the present invention;

[0033] Figure 2b shows a number of schematic views of alternative example test blocking components according to the present invention;

[0034] Figure 3is a schematic cross-section through an example operational barrier component according to the present application engaged with a wall of an example diffuser;

[0035] Figure 4 is a schematic cross-section through an example test barrier component according to the present application blocking an outlet of an example diffuser;

[0036] Figure 5 is a schematic cross-section through an example operational barrier component according to the present application engaged with a wall of an example diffuser;

[0037] Figure 6 shows a number of schematic views of an example test barrier component according to the present application;

[0038] Figure 7 is a schematic cross-section through another example fuel system according to the present application;

[0039] Figure 8 is a schematic view of an example kit of parts according to the present application;

[0040] Figure 9 is a flowchart illustrating an example method according to the present application; and

[0041] Figure 10 is a perspective view of an example aircraft according to the present application. DETAILED DESCRIPTION

[0042] Each example fuel system described herein is suitable for use in an aircraft, and each example fuel system comprises a fuel tank for storing fuel during operation of the aircraft, and a diffuser. The diffuser is disposed inside the fuel tank and is configured such that the diffuser forms part of a flow path configured to connect a fuel source to an interior of the fuel tank. The diffuser comprises a wall at least partially defining an interior space of the diffuser, an opening in the wall providing access to the interior space, and a barrier component configured to block the opening.

[0043] The opening in the wall of the diffuser advantageously enables access to the inlet of the fuel tank whilst the diffuser is fitted. This allows the inlet to be blocked so that the pipe system upstream of the inlet can be pressure tested without the need to remove the diffuser. The barrier component is configured to be simply and quickly installed over the opening, such that the process of installing the barrier component over the diffuser is quicker compared to the process of removing and refitting the diffuser. As a result, the assembly time for an aircraft having a fuel system according to the present application is reduced.

[0044] Figure 1aAn example fuel system 1 according to the present application is shown, the fuel system 1 being for an aircraft. The fuel system 1 includes a fuel tank 10 for storing fuel during operation of the aircraft in which the fuel system 1 is installed. The fuel tank 10 is configured to store liquid fuel, and is shown as being partially filled with liquid fuel 102. The ullage space 101 of the fuel tank 10 is filled with a gas (e.g. air or an inert gas). The fuel tank 10 can be formed from a structural component of the aircraft. In such examples, one or more walls of the fuel tank 10 can be formed from a wing rib, a wing skin panel, a spar, or any other structural component of a wing. In some examples, the fuel tank 10 is formed from a wing box of the aircraft. The fuel tank includes one or more outlets (not shown) through which fuel is delivered to an engine of the aircraft.

[0045] The fuel system 1 also includes a diffuser 11 disposed inside the fuel tank 10. The diffuser 11 is configured and positioned such that the diffuser forms part of a flow path configured to connect a fuel source to an interior of the fuel tank 10. The diffuser 11 is located near a bottom of the fuel tank 10. The direction of flow of fuel through the diffuser 11 into the fuel tank 10 is indicated by the box-shaped arrow. In particular, the diffuser 11 is disposed on (or in) an inlet 103 of the fuel tank 10. In some examples, the diffuser 11 is connected to (i.e. the diffuser 11 is in fluid communication with) a fuel delivery line (not shown) that extends between the inlet 103 and a fuel source (or a port connectable to a fuel source). Figure 1b and Figure 1c The diffuser 11 is shown in more detail, independently of the fuel tank 10.

[0046] Figure 1b and Figure 1c is a cross-section through the diffuser 11. Figure 1b The diffuser 11 is shown in a test configuration suitable for pressure testing a refuelling pipe system connected to the fuel system 1. Figure 1c The diffuser 11 is shown in an operational configuration, suitable for operation of an aircraft in which the fuel system 1 is installed. The illustrated diffuser 11 includes a cuboid body member formed from five walls, which together define an interior space 113 of the body member. The lower side of the body member (relative to the direction of flow of fuel through the diffuser 11) is shown as being substantially flat. The diffuser 11 is shown in a configuration in which the body member is connected to the inlet 103 of the fuel tank 10. In particular, the diffuser 11 is shown as being connected to the inlet 103 of the fuel tank 10 by a flange 111 of the diffuser 11. The flange 111 is shown as being substantially flat, and is configured to abut the inlet 103 of the fuel tank 10. In some examples, the flange 111 is configured to abut a portion of the inlet 103 of the fuel tank 10 that is formed from a structural component of the aircraft (e.g. a wing rib, a wing skin panel, a spar, or any other structural component of a wing). Figures 1a to 1cThe open end of the pipe 112 is open (as shown in the orientation in the figure). A pipe 112 configured to sealingly connect to a fuel delivery conduit system extends through one wall of the body member and into the interior space 113 of the body member. The end of the pipe 112 disposed within the interior space 113 is open to allow fuel to pass through the pipe 112 into the interior space 113 of the diffuser 11. Thus, the open end of the pipe 112 is an outlet through which fuel flows into the interior space 113 of the diffuser 11 during delivery of fuel to the fuel tank 10.

[0047] An opening 13 is provided in the wall 111 of the body member. The wall 111 is opposite the wall through which the pipe 112 extends. The opening 13 provides access to the interior space 113. The opening 13 is positioned such that it provides access to the open end of the pipe 112. In the illustrated example, the opening 13 is substantially coaxial with the pipe 112. The opening 13 is at least as large as the internal diameter of the pipe 112, and can be substantially larger (as is the case in the illustrated example). The opening 13 can (but need not) be circular. The opening 13 is configured to be engageable with at least two different types of blocking member, each of which is configured to block the opening 13.

[0048] The diffuser 11 further comprises blocking members 12a, 12b configured to block the opening 13. The blocking members can be a test blocking member 12a or an operational blocking member 12b, as will be explained below with reference to Figure 1b and Figure 1c The blocking members 12a, 12b are removably engaged with the wall 111 of the diffuser 11. In some examples, the blocking members 12a, 12b are removably engaged with the pipe 112. In some examples, the blocking members 12a, 12b and the wall 111 each comprise interlocking features configured to interlock to retain the blocking members 12a, 12b on the wall 111. In some examples, the engagement mechanism is configured such that the blocking members 12a, 12b can be manually engaged with and disengaged from the wall 111 by an operator without the use of any tools.

[0049] Figure 2a and Figure 2b Two alternative engagement mechanisms by which a blocking member can be removably engaged with a wall of a diffuser according to the present application are shown. The illustrated diffuser walls 211a, 211b each have the same general features as the diffuser wall 111 described above. The illustrated blocking members 22a, 22b are test blocking members, each of which has substantially the same features as the example test blocking member 12a. However, Figure 2a and Figure 2b The illustrated engagement mechanisms can equally be applied to operational blocking members, such as the example operational blocking member 12b.

[0050] Figure 2a The example engagement mechanism illustrated in FIG. 21 is based on threads. In this example, the diffuser wall 211a includes a cylindrical rim 215a extending perpendicularly from the outer surface of the wall 211a. The rim 215a surrounds the opening 13, and in this example, the rim 215a is coaxial with the opening 13. The diameter of the rim 215a is greater than the diameter of the opening 13. A thread 216 is provided on the inner surface of the rim 215a. A corresponding thread 217 is provided on the outer circumferential surface of the plate portion 221a of the blocking component 22a. The plate portion 221a is configured such that, when the blocking component 22a is engaged with the wall 211a, the thread 217- provided outer circumferential surface is arranged adjacent to the inner surface of the rim 215a.

[0051] Accordingly, the blocking component 22a can be engaged with the wall 211a by arranging the blocking component 22a coaxially with the rim 215a such that the threads 216, 217 are in contact, and then rotating the blocking component 22a relative to the wall 211a in a direction such that the interaction of the threads 216, 217 drives the blocking component 22a towards the wall 211a. Rotation can be continued until the blocking component 22a is in contact with the wall 211a. A "handle" feature 224a protrudes from the outer surface of the plate portion 221a to facilitate rotation of the blocking component 22a by an operator. The handle feature 224a can be configured to be easily gripped by a hand, such that a tool is not required to engage the blocking component 22a with the wall 211a.

[0052] Figure 2b The example engagement mechanism illustrated in FIG. 21 is based on threads. In this example, the diffuser wall 211a includes a cylindrical rim 215a extending perpendicularly from the outer surface of the wall 211a. The rim 215a surrounds the opening 13, and in this example, the rim 215a is coaxial with the opening 13. The diameter of the rim 215a is greater than the diameter of the opening 13. A thread 216 is provided on the inner surface of the rim 215a. A corresponding thread 217 is provided on the outer circumferential surface of the plate portion 221a of the blocking component 22a. The plate portion 221a is configured such that, when the blocking component 22a is engaged with the wall 211a, the thread 217- provided outer circumferential surface is arranged adjacent to the inner surface of the rim 215a. Figure 2a The example rim 215a has substantially the same features as the rim 215a of the example, except that, instead of being threaded, the rim 215b includes four radially extending tabs 218 protruding inwardly from the distal end of the rim 215b. In the illustrated example, the tabs 218 are evenly distributed around the rim 215b, with an angular separation of 90° between adjacent tabs, although this can be different in other examples.

[0053] The plate portion 221b of the blocking component 22b includes four recesses 223, the configuration and location of which correspond to the configuration and location of the tabs 218. When the blocking component 22b and the rim 215b are coaxially and opposingly oriented such that the tabs 218 are aligned with the recesses 223 (as illustrated in FIG. 22), the blocking component 22b can be engaged with the rim 215b by arranging the blocking component 22b coaxially with the rim 215b, such that the tabs 218 are in contact with the recesses 223, and then rotating the blocking component 22b relative to the rim 215b in a direction such that the interaction of the tabs 218, 223 drives the blocking component 22b towards the rim 215b. Rotation can be continued until the blocking component 22b is in contact with the rim 215b.Figure 2b In the case of the arrangement of parts (ii) and (iii) of Figure 2, the plate portion 221b of the blocking component 22b can be received within the recess defined by the edge 215b such that the plate portion 221b is in contact with the outer surface of the wall 211b.

[0054] Thus, the blocking component 22b can be engaged with the wall 211b by arranging the blocking component 22b to be coaxial with the edge 215b at a rotational position relative to the edge 215b such that the recess 223 is aligned with the protrusion 218. The blocking component 22b is then moved axially towards the wall 211b until the plate portion 221b contacts the outer surface of the wall 211b. The blocking component 22b is then rotated relative to the wall 211b between 5° and 85° such that the recess 223 is no longer aligned with the protrusion 218. This is the state shown in part (i) of Figure 2. Figure 2b As can be seen from part (i) of Figure 2, in this misaligned state the protrusion 218 acts to prevent the blocking component 22b from moving axially away from the wall 211b. The blocking component 22b comprises a handle feature 224b having substantially the same features as the handle feature 224a to facilitate rotation of the blocking component 22a by an operator. Figure 2b

[0055] Returning to Figure 1, in some examples the fuel system 1 comprises a locking member configured to engage with the blocking component 12a, 12b and with the wall 111 to prevent the blocking component 12a, 12b from disengaging from the wall 111. In some examples the fuel system 1 comprises a plurality of such locking members. The locking member can take any suitable form known in the art.

[0056] Figure 3 A particular example locking member 30 suitable for use with the fuel system 1 is shown, which retains a blocking component 32 on a wall 311 of a diffuser. The illustrated diffuser wall 311 has the same general features as the diffuser wall 111 described above. The illustrated blocking component 32 is an operational blocking component having substantially the same features as the example operational blocking component 12b. However, the locking member 30 can equally be applied to a test blocking component, such as the example test blocking component 12a.

[0057] ​The illustrated example locking member 30 comprises a bolt 301 which engages with a nut 302. The shank of the bolt 301 extends through the barrier member 32 and a wall 311. The nut 302 is held against the inner surface of the wall 311 by any suitable mechanism. In other examples, the hole in the wall through which the shank of the bolt 301 extends is threaded, in which case the nut 302 is omitted. The locking member 30 can be mounted so that the barrier member 32 is clamped against the wall 311. The locking member 30 acts to prevent the barrier member 32 from moving relative to the wall 311. In some examples, more than one such locking member 30 can be engaged with the barrier member 32 and the wall 311. This can facilitate preventing the barrier member 32 from rotating relative to the wall 311.

[0058] Returning to Figure 1, in Figure 1b the first type of barrier member 12a is provided on the wall 111 of the diffuser 11 and blocks the opening 13. The first type of barrier member 12a is a test barrier member which is configured to block the flow path of fuel into the fuel tank 10. Thus, the test barrier member 12a prevents fuel from flowing into the fuel tank 10 when the test barrier member 12a is mounted on the diffuser 11. In the illustrated example, the test barrier member 12a achieves the blocking of the flow path by having a sealing member 122 which is configured to block the outlet of the diffuser 11 (in the illustrated example, this is the open end of the pipe 112).

[0059] In addition to the sealing member 122, the test barrier member 12a comprises a plate member 121 which is configured to block the opening 13. The sealing member 122 is integrally formed with the plate member 121. The plate member 121 is configured to be provided on the outer surface of the wall 111 and to completely cover the opening 13. The outer surface of the plate member 121 can comprise one or more features (not shown) which are configured to enable the test barrier member 12a to be easily grasped and manipulated by an operator.

[0060] The plate member 121 is configured to removably engage with the wall 111 to hold the test barrier member in a desired position relative to the wall 111. For example, the engagement between the plate member 121 and the wall 111 can be configured to resist axial movement of the test barrier member 12a relative to the wall 111, even in the face of a force acting to drive the test barrier member 12a away from the wall 111. Thus, such engagement ensures that the test barrier member 12a blocks the outlet of the pipe 112, even when the interior of the pipe is pressurised to a high pressure, as occurs during pressure testing of a fuel delivery pipe system connected to the diffuser 11. The engagement mechanism can take any suitable form, for example interlocking features and / or one or more locking members, as described above.

[0061] The sealing member 122 extends from an inner surface of the plate member 121 (i.e. the surface facing towards the interior space 113 of the diffuser 11). The sealing member 122 is configured to create a pressure-tight seal with the open end of the conduit 112. The sealing member 122 is generally cylindrical and has an outer diameter equal to the inner diameter of the outlet of the conduit 112. When the test barrier 12a is installed on the diffuser 11, the sealing member 122 is coaxial with the conduit 112. The axial length of the sealing member 122 is greater than the distance between the outlet of the conduit 112 and the wall 111 (in the axial direction of the conduit 112). This means that the distal end of the sealing member 122 extends into the conduit 112. In some examples, the sealing member 122 is dimensioned so that it is an interference fit in the conduit 112.

[0062] In other examples, the sealing member 122 can have a different configuration to that shown in Figure 1b . Indeed, any configuration that enables a pressure-tight seal between the sealing member 122 and the open end of the conduit 112 can be used. In one such alternative example, the distal end of the sealing member 122 comprises an axially extending cylindrical recess having an inner diameter equal to the outer diameter of the open end of the conduit 112. In this example, the open end of the conduit 112 is received within the recess and the outer surface of the conduit 112 is in close contact with the inner surface of the recess to form a seal.

[0063] In some examples, an additional sealing component is provided between the sealing member and the conduit to facilitate a pressure-tight seal between the sealing member 122 and the conduit when the test barrier 12a is installed on the diffuser 11. In examples in which the sealing member has the configuration shown in Figure 1b , such an additional sealing component is provided between the outer surface of the sealing member and the inner surface of the conduit 112. The additional sealing component can be held against the sealing member by any suitable mechanism. The additional sealing component can take any suitable form known in the art, for example a ring made of an impermeable, resilient material.

[0064] Figure 4 An example test barrier 42 comprising an additional sealing component 43 is shown in Figure 1b . The test barrier 42 is substantially identical to the test barrier 12a of Figure 4omitted. In this example, the additional sealing component 43 is an elastomeric ring member that is bonded to the outer surface of the distal end of the sealing member 422 of the test barrier component 42. The elastomeric ring member can be formed of any suitable material, such as rubber or elastomer. In some examples, at least the outer surface of the elastomeric ring member can be formed of a low-friction material to facilitate insertion of the sealing member 422 into the open end of the conduit 112.

[0065] Returning to Figure 1b In some examples, the test barrier component 12a includes a port configured to engage with a pressure test device such that the pressure test device can measure pressure in the flow path upstream of the test barrier component 12a when engaged with the port.

[0066] Figure 6 An example test barrier component 62 is shown that includes a pressure test port 64. Part (i) is an axial view that shows the outer surface of the plate member 621 of the test barrier component 62, and part (ii) is a cross-section through the test barrier component 62 engaged with the diffuser conduit 112 (the remainder of the diffuser is omitted for clarity). The example test barrier component 62 is substantially identical to the example test barrier component 12a of Figure 1b except for the pressure test port 64. The pressure test port 64 includes a bore that extends axially from the outer surface of the plate member 621 through the test barrier component 62 to the distal end of the barrier member 622. The opening 641 of the bore, at which the bore interfaces with the outer surface of the plate member 621, is configured to engage with a pressure test device (not shown) configured to measure pressure within the sealed volume. In particular, the pressure test device is configured to measure pressure upstream of the diffuser conduit 112 and within the fuel delivery conduit system that includes the diffuser conduit 112.

[0067] The pressure test port 64 is configured to engage with the pressure test device such that a pressure-tight seal is formed between the port 64 and the pressure test device when the pressure test device is engaged with the port 64. Such engagement can be achieved by providing cooperating features on the port opening 641 and the pressure test device, such as corresponding threads. In some examples, the port opening 641 can include any suitable type of sealing element to facilitate the pressure-tight seal between the port 64 and the pressure test device.

[0068] Returning to FIG. 1, in Figure 1cIn this embodiment, a second type of barrier member 12b is provided on the wall 111 of the diffuser 11 and blocks the opening 13. The second type of barrier member 12b is an operational barrier member configured to allow fuel to flow from a fuel source connected to the inlet of the fuel tank 10 into the fuel tank 10 when the operational barrier member 12b is mounted on the diffuser 11. The operational barrier member 12b achieves this by blocking the opening 13 without blocking the open end of the conduit 112.

[0069] The operational barrier member 12b is in the form of a plate or cover configured to block the opening 13. The operational barrier member 12b is configured to be provided on the outer surface of the wall 111 and to completely cover the opening 13. The outer surface of the operational barrier member 12b can include one or more features (not shown) configured to enable the operational barrier member 12b to be grasped and manipulated by an operator. The operational barrier member 12b is removably engaged with the wall 111. The engagement mechanism can take any suitable form, for example interlocking features and / or one or more locking members, as described above.

[0070] The operational barrier member 12b can have substantially the same configuration as the plate member 121 of the test barrier member 12a. This enables the same engagement mechanism used to hold the test barrier member 12a on the wall 111 to be used to hold the operational barrier member 12b on the wall 111. In this way, the operational barrier member 12b and the test barrier member 12a can be easily interchanged on the diffuser 11.

[0071] In some examples, a sealing element is provided between the outer surface of the wall 111 and the operational barrier member 12b. The sealing element is configured to prevent fuel from flowing through the opening 13. The sealing element can be attached to the outer surface of the wall 111 or to the inner surface of the operational barrier member 12b by any suitable mechanism. The sealing element can be a face seal. The sealing element can take any suitable form known in the art, for example a ring made of an impermeable elastomeric material.

[0072] Figure 5 An example operational barrier member 52 including a sealing element 53 is shown in Figure 5. The operational barrier member 52 is substantially the same as the operational barrier member 12b of Figure 1c Figure 4, except for the sealing element. The operational barrier member 52 is shown in an operational state in which the operational barrier member 52 blocks the opening 13 in the wall 111 of the diffuser 11. The remainder of the diffuser 11 is shown from the same perspective as Figure 5 is omitted. In this example, the sealing element 53 is an elastomeric ring member bonded to the inner surface of the operational barrier member 52. The elastomeric ring member can be formed from any suitable material, for example rubber or elastomer.

[0073] In some examples, the operational barrier member 12b is provided with a handle 54. The handle 54 can be provided on the outer surface of the operational barrier member 12b. The handle 54 can be used to facilitate the removal and installation of the operational barrier member 12b on the wall 111 of the diffuser 11. Figure 1aThe fuel system 1 comprises a fuel delivery apparatus forming a further part of the flow path configured to connect the fuel source to the interior of the tank 10. Figure 7 An example fuel system 7 is shown. The fuel system 7 comprises a fuel tank 10 and a diffuser 11, and a fuel delivery conduit 70. The fuel tank 10 is shown in an empty state. Figure 7 Although the fuel delivery conduit 70 is shown as a single straight conduit section for ease of description, the fuel delivery conduit 70 can more typically comprise a plurality of conduit sections. The fuel delivery conduit 70 can comprise one or more fittings, bends, intersections, etc. The fuel delivery conduit 70 can comprise or be connected to one or more fuel delivery related devices, such as pumps, valves, filters, etc.

[0074] A first end 701 of the fuel delivery conduit 70 is sealingly connected to the conduit 112 of the diffuser by a connector 71. The connector 71 can have any suitable design. In other examples are possible in which at least a portion of the fuel delivery conduit 70 is integrally formed with the diffuser conduit 112. A second end 702 of the fuel delivery conduit 70 is connected or connectable to a fuel source 72 (indicated by the box-shaped arrow in Figure 7 ). For example, the second end 702 can be connected to a refuelling port of the aircraft or to another fuel tank of the aircraft. The second end 702 can comprise a connector adapted to form a connection to the fuel source 72. Fuel 102 flowing from the fuel source 72 along the fuel delivery conduit 70 to the diffuser 11 is shown entering the fuel tank 10 in the form of a box-shaped arrow.

[0075] Figure 8 A kit of parts 8 is shown, the kit of parts 8 being configured to form a fuel system according to the present application, for example Figure 1a an example fuel system 1. The kit of parts 8 comprises: a fuel tank 80, a diffuser 81; a test blocking part 82a; and an operational blocking part 82b. The test blocking part 82a and the operational blocking part 82b are engageable with a wall 811 of the diffuser 81 in an interchangeable manner. Figure 8 The fuel tank 80 and the diffuser 81 are shown in cross-section, with the plane of the cross-section being parallel to the open side of the diffuser 81. The fuel tank 80 has an inlet 803 through which fuel can flow into the fuel tank 80, and the diffuser 81 is disposed inside the fuel tank and connected to the inlet 803.

[0076] The diffuser 81 comprises a wall 811 defining the opening 83 and configured to engage with the test blocking component 82a and with the operational blocking component 82b. The test blocking component 82a is configured to engage with the wall 811 to block the opening 83 and to prevent fuel from flowing from a fuel source connected to the inlet 803 into the fuel tank 80 when the test blocking component 82a is engaged with the wall 811. The operational blocking component 82b is configured to allow fuel to flow from a fuel source connected to the inlet 803 into the fuel tank 80 when the operational blocking component 82b is engaged with the opening 83. The components of the kit 8 have the same features as the corresponding components of the fuel system 1 described above.

[0077] In some examples, the kit further comprises a locking component 801 configured to engage with the operational blocking component 82b and with the wall 811 when the operational blocking component 82b is engaged with the wall 811, such that the operational blocking component 82b is prevented from disengaging from the wall 811 by the locking component 801. In some examples, the locking component can also be configured to engage with the test blocking component 82a and with the wall 811 when the test blocking component 82a is engaged with the wall 811, such that the test blocking component 82a is prevented from disengaging from the wall 811 by the locking component 801. The locking component 801 has the same features as the example locking component of Figure 3 In some examples, the kit can comprise a plurality of locking components 801.

[0078] Figure 9 is a flowchart illustrating a method 900 for manufacturing an aircraft. Performing the method results in the production of a fuel system according to the present application, such as any of the example fuel systems 1, 7 described above. In some examples, the method can comprise assembling a kit according to the present application, such as the example kit 8 described above. The method can be performed as part of a process for testing a fuel system of an aircraft being manufactured.

[0079] The first block 901 of the method 900 comprises providing a fuel tank component configured to form at least part of a fuel tank of an aircraft. The fuel tank component can be adapted to form at least part of a fuel tank having the features of the example fuel tank 10 or the example fuel tank 80 described above. The fuel tank component can comprise one or more structural components of the aircraft. In some examples, the fuel tank component comprises one or more structural wing components. In some examples, the fuel tank component is provided already assembled into a fuel tank. In some such examples, providing the fuel tank component can comprise providing an aircraft structure forming a fuel tank, such as a wing box.

[0080] The fuel tank component is arranged to be connected to a fuel delivery apparatus, which can have Figure 7Any of the features of the example fuel delivery apparatus. The fuel delivery apparatus is configured to define a flow path between a fuel source and an interior of a fuel tank, the fuel tank components forming (or intended to form) at least a portion of the fuel tank. The fuel delivery apparatus includes a diffuser intended to be disposed within the fuel tank. The diffuser can have the same features as the example diffusers 11 described above. The fuel delivery apparatus can also include one or more pipes, valves, connectors, etc. The fuel delivery apparatus can include all components that define a flow path for fuel between a fuel source (e.g., a fueling port of an aircraft) and an interior of a fuel tank.

[0081] In some examples, the execution block 901 can include connecting the fuel delivery apparatus to the fuel tank components. Connecting the fuel delivery apparatus to the fuel tank includes forming a fluid-tight seal between the fuel delivery apparatus and the fuel tank components (in any suitable manner). The fuel tank components can not yet be connected to other fuel tank components when the fuel delivery apparatus is connected to the fuel tank components, such that the fuel tank is in an unassembled or partially assembled state. In other examples, the execution block 901 includes providing a pre-assembled fuel system, e.g., as part of a substantially complete aircraft wing structure in a state to be joined to a fuselage structure.

[0082] In a second block 902, a test barrier component is arranged on the diffuser such that the test barrier component blocks the flow path and prevents fluid flow between an interior space of the fuel delivery apparatus and an interior of the fuel tank, the fuel tank components to form a portion of the fuel tank. The test barrier component can have the same features as any of the example test barrier components 12a, 22a, 22b, 42, 62, 82a described above. The test barrier component is arranged on the diffuser in any manner suitable for the particular design of the test barrier component such that the blocking function is achieved. For example, arranging the test barrier component on the diffuser can include engaging the test barrier component with a wall of the diffuser in any of the manners described above with respect to the example test barrier components 12a, 22a, 22b, 42, 62, 82a.

[0083] In a third block 903, a pressure test is performed on the fuel delivery apparatus. In examples in which the fuel tank components are provided unassembled into the fuel tank, the pressure test is performed prior to assembling the fuel tank components into the fuel tank. This can be advantageous to enable easy access to the fuel tank and fuel delivery apparatus for purposes of performing the test and / or repairing any issues identified by the test. Alternatively, in examples in which the fuel tank components are provided already assembled into the fuel tank, the pressure test is performed when the fuel tank is in an assembled state. It can be desirable to perform the pressure test after assembly of the fuel tank in case any damage to the fuel delivery system occurred during the assembly process of the fuel tank.

[0084] The pressure test can be performed by a pressure testing device. Performing the pressure test can include engaging such a pressure testing device with a port included in the test barrier device, as described above with respect to Figure 6 The pressure test can be performed in any suitable manner known in the art.

[0085] In block 904, the test barrier component is replaced with an operational barrier component that allows fluid to flow between the interior space of the fuel delivery apparatus and the interior of the fuel tank. The operational barrier component can have the same features as any of the example operational barrier components 12b, 32, 52, 82b described above. Replacing the test barrier component with the operational barrier component includes removing the test barrier component from the diffuser (e.g., by disengaging the test barrier component from the wall of the diffuser in any suitable manner according to the nature of the engagement) and then arranging the operational barrier component on the diffuser.

[0086] The operational barrier component is arranged on the diffuser in any manner suitable for the particular design of the operational barrier component. For example, arranging the operational barrier component on the diffuser can include engaging the operational barrier component with the wall of the diffuser in any of the manners described above with respect to the example barrier components of FIGS. 1-3. Figure 5 The operational barrier component can be arranged on the diffuser securely enough that the operational barrier component does not disengage from the diffuser during normal operation of the aircraft.

[0087] Block 904 can be performed prior to assembling the fuel tank components into the fuel tank. However, it is more typical for block 904 to be performed after assembling the fuel tank components into the fuel tank, as this allows the pressure test to be performed during the aircraft assembly process, when the risk of any damage by the fuel delivery apparatus is negligible. As mentioned above, the design of the diffuser and the design of the test barrier component and the operational barrier component facilitate performing the pressure test in the assembled state of the fuel tank, as these items are configured such that the process of engaging and disengaging the test barrier component and the operational barrier component from the diffuser is simple and easy to perform, even with limited access.

[0088] In optional fifth block 905, the fuel tank components are assembled into the fuel tank. Block 905 is only performed if the fuel tank components are provided in block 901, prior to the fuel tank components being assembled into the fuel tank. Performing block 905 can include assembling aircraft structure that forms all or part of the fuel tank, such as a wing box. After completing block 905, the fuel tank components can be included in a substantially fully assembled aircraft wing that is substantially ready to be joined to a fuselage of an aircraft.

[0089] Figure 10An example aircraft 1000 is shown that includes a fuel system according to the present application (e.g., the example fuel system 1 or the example fuel system 7 described above). The aircraft 1000 includes a fuselage 1001, a pair of wings 1002a and 1002b, a pair of engines 1003a and 1003b, and a tail 1004.

[0090] The aircraft 1000 includes a plurality of fuel tanks (not visible) and a fuel distribution system for delivering fuel from the fuel tanks to the engines 1003a, 1003b. For example, the fuel tanks can include sealed compartments formed at least partially by the structure of the wings 1002a, 1002b, the tail 1004, and / or the fuselage 1001 and / or any other portion of the aircraft 1000. The aircraft 1000 also includes a fueling port (not visible) and a fuel delivery apparatus (not visible) configured to provide a flow path for fuel between the fueling port and one or more of the fuel tanks. An inlet of each fuel tank can be connected to the fuel delivery apparatus, and a diffuser within each fuel tank can be connected to the inlet of that fuel tank. At least some of the diffusers on the aircraft have the same general features as the example diffuser 11, and these diffusers, in combination with the fuel tank in which the diffuser is located, form a fuel system according to the present application.

[0091] In particular, each fuel tank formed by the structure of one of the wings 1002a, 1002b includes a diffuser having the same general features as the diffuser 11. Thus, each wing 1002a, 1002b includes a fuel system according to the present application. Each wing fuel tank system according to the present application can be manufactured according to the example method 1000 described above.

[0092] Although the present application has been described above with reference to one or more preferred examples or embodiments, it will be appreciated that various changes or modifications can be made without departing from the scope of the present application as defined in the appended claims.

[0093] Although the present application has been described above primarily in the context of fixed-wing aircraft applications, the present application can also be advantageously applied to a variety of other applications, including but not limited to applications on vehicles such as helicopters, drones, trains, automobiles, and spacecraft.

[0094] Where the term "or" is used in the preceding description, this term is used in the sense that it is used in the patent law, unless otherwise explicitly indicated.

Claims

1. A fuel system for an aircraft, the fuel system comprising: a fuel tank for storing fuel during operation of the aircraft; and a diffuser disposed within the fuel tank and forming part of a flow path configured to connect a fuel source to the interior of the fuel tank; wherein the diffuser comprises: a wall at least partially defining an interior space for fuel in the diffuser; a fuel inlet configured to pass fuel from the fuel source into the interior space, wherein the fuel inlet comprises a fuel conduit extending through the wall, the fuel conduit having an open end through which fuel flows from the fuel inlet into the diffuser, wherein the open end of the fuel conduit is spaced apart from the wall; a fuel outlet in the wall configured to allow fuel to flow from the diffuser to the interior of the fuel tank; an opening in the wall providing access from the fuel tank to the interior space, wherein the opening is spaced apart from the fuel inlet and the fuel outlet; and a blocking member configured to block the opening.

2. The fuel system of claim 1, wherein, the blocking member is removably engaged with the wall.

3. The fuel system of claim 2, further comprising a locking member configured to engage with the blocking member and the wall to prevent the blocking member from disengaging from the wall.

4. The fuel system of any one of claims 1-3, wherein, the blocking member and the wall each comprise interlocking features configured to interlock to retain the blocking member on the wall.

5. The fuel system of any one of claims 1 to 3, further comprising a sealing element between the blocking member and the wall, the sealing element configured to prevent fuel flow through the opening.

6. The fuel system of any one of claims 1-3, wherein, the blocking member comprises a test blocking member and an operational blocking member, wherein the operational blocking member, when blocking the opening, prevents fuel flow through the opening and into the interior of the fuel tank without blocking the fuel inlet, and wherein the test blocking member, when blocking the opening, extends from the opening through a portion of the interior space and to the fuel inlet to prevent fuel flow into the diffuser through the fuel inlet.

7. The fuel system of any one of claims 1 to 3, further comprising a fuel delivery device forming another portion of the flow path, wherein, a first end of the fuel delivery apparatus is connectable to the fuel source and a second end of the fuel delivery apparatus is connected to the fuel inlet.

8. The fuel system of any one of claims 1-3, wherein, the fuel tank is formed from a structural component of the aircraft.

9. The fuel system of claim 8, wherein, the fuel tank is formed from a wing box of the aircraft.

10. The fuel system of any one of claims 1-3, wherein, the blocking member is a test blocking member and is configured to block the flow path to prevent fuel flow into the fuel tank.

11. The fuel system of claim 10, wherein, the test blocking member comprises a sealing member configured to block the fuel inlet.

12. The fuel system of claim 11, wherein, the sealing member is configured to form a pressure-tight seal against the fuel inlet.

13. The fuel system of claim 10, wherein, the test blocking member comprises a port configured to be engageable with a pressure testing device such that the pressure testing device can measure pressure in the flow path upstream of the test blocking member when engaged with the port.

14. The fuel system of any one of claims 1-3, wherein, The blocking component is an operational blocking component and is configured to allow fuel to flow from the fuel source, through the diffuser, and out of the fuel outlet into the fuel tank when the operational blocking component is engaged with the opening.

15. A kit of parts comprising: a fuel tank having an inlet through which fuel can flow into the fuel tank; a diffuser disposed within an interior of the fuel tank, the diffuser being connected to the inlet; wherein the diffuser comprises: a wall at least partially defining an interior space for fuel in the diffuser; a fuel inlet configured to pass fuel from a fuel source into the interior space, wherein the fuel inlet comprises a fuel conduit extending through the wall, the fuel conduit having an open end through which fuel flows from the fuel inlet into the diffuser, wherein the open end of the fuel conduit is spaced apart from the wall; a fuel outlet in the wall configured to allow fuel to flow from the diffuser to an interior of the fuel tank; an opening in the wall providing access from the fuel tank to the interior space, wherein the opening is spaced apart from the fuel inlet and the fuel outlet; a test blocking component configured to engage with the wall to block the opening, wherein the test blocking component is configured to prevent fuel from flowing from a fuel source connected to the inlet into the fuel tank when the test blocking component is engaged with the wall; and an operational blocking component configured to engage with the wall to block the opening, wherein the operational blocking component is configured to allow fuel to flow from a fuel source connected to the inlet into the fuel tank when the operational blocking component is engaged with the opening.

16. The kit of parts of claim 15, further comprising a locking component configured to engage with the operational blocking component and the wall when the operational blocking component is engaged with the wall such that the operational blocking component is prevented from disengaging from the wall.

17. An aircraft comprising the fuel system of claim 14.

18. A method for manufacturing an aircraft, the method comprising: providing a fuel tank component configured to form at least a portion of an aircraft fuel tank connected to a fuel delivery apparatus, the fuel delivery apparatus being configured to define a flow path between a fuel source and an interior of the fuel tank and comprising a diffuser configured to be disposed within the fuel tank, wherein the diffuser comprises: a wall at least partially defining an interior space for fuel in the diffuser; a fuel inlet configured to pass fuel from the fuel source into the interior space, wherein the fuel inlet comprises a fuel conduit extending through the wall, the fuel conduit having an open end through which fuel flows from the fuel inlet into the diffuser, wherein the open end of the fuel conduit is spaced apart from the wall; a fuel outlet in the wall, the fuel outlet configured to allow fuel to flow from the diffuser to an interior of the fuel tank; an opening in the wall, the opening providing access from the fuel tank to the interior space, wherein the opening is spaced apart from the fuel inlet and the fuel outlet; arranging a test blocking component in the opening of the diffuser such that the test blocking component blocks the flow path and prevents fluid flow between the interior space of the fuel delivery apparatus and the interior of the fuel tank; performing a pressure test on the fuel delivery apparatus; replacing the test blocking component with an operational blocking component that allows fluid flow between the interior space of the fuel delivery apparatus and the interior of the fuel tank.

19. The method of claim 18, further comprising: assembling the fuel tank component into a fuel tank after replacing the test blocking component with the operational blocking component.

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