Aircraft fuel tank barrier

Abstract

Disclosed is an isolator for an aircraft fuel tank, the isolator configured to isolate a conductive interior panel of the fuel tank from a conductive duct passing through the panel. The isolator comprises: a plurality of first attachment points for attaching the isolator to the panel; a plurality of second attachment points for attaching the isolator to the duct; and an aperture defined by an outer wall and extending from a first side of the isolator to a second side of the isolator, the aperture configured to receive the duct in use; wherein the isolator comprises a non-conductive material. Also disclosed is an isolation system, an aircraft and a method of isolating a conductive interior panel or an aircraft fuel tank from a conductive duct passing through the panel.

Description

Technical Field

[0001] This invention relates to an isolator for an aircraft fuel tank, as well as an isolation system, isolation method, and aircraft. Background Technology

[0002] In some aircraft, the fuel tank has an irregular shape. Therefore, the fuel tank typically comprises multiple sections defined by segmented walls or panels. These panels may extend generally vertically between the top and bottom of the wing. For example, in some aircraft, the fuel tank is located within the wing and positioned around other equipment located within the wing.

[0003] For example, other equipment located in the wings can be connected to the aircraft fuselage via pipes that pass through the aircraft's fuel tank. In some cases, the pipes pass through the fuel tank panel. For example, pipes can deliver hydraulic fluid from a hydraulic supply unit to a hydraulic actuator. In some cases, the pipes must pass through section walls. Summary of the Invention

[0004] A first aspect of the invention provides an isolator for an aircraft fuel tank, the isolator being configured to separate a conductive inner panel of the fuel tank from a conductive conduit passing through the panel, the isolator comprising: a plurality of first attachment points for attaching the isolator to the panel; a plurality of second attachment points for attaching the isolator to the conduit; and an orifice defined by an outer wall and extending from a first side of the isolator to a second side of the isolator, the orifice being configured to receive the conduit in use, wherein the isolator comprises a non-conductive material.

[0005] Optionally, the outer wall of the orifice extends outward from the first side of the isolator to form a tube, wherein the tube is configured to pass through the panel during use.

[0006] Optionally, a plurality of first attachment points and a plurality of second attachment points are positioned on a flange extending from the outer wall of the orifice.

[0007] Optionally, the first attachment point includes a countersunk hole extending from a second side of the isolator to a first side of the isolator, wherein the wider end of the countersunk hole extends from the second side of the isolator.

[0008] Optionally, the first attachment point is positioned around the orifice to align with the corresponding panel orifice in the panel.

[0009] Optionally, the second attachment point includes a countersunk hole extending from a first side of the isolator to a second side of the isolator, wherein the wider end of the countersunk hole extends from the first side of the isolator.

[0010] Optionally, the second attachment point is positioned around the orifice to align with the corresponding fitting orifice in the pipe fitting fixed to the pipe.

[0011] Optionally, the isolator includes a groove located on a first side and / or a second side of the isolator, the groove extending around the outer wall of the orifice and configured to receive a seal.

[0012] Alternatively, the isolator may be formed of a chemically inert material.

[0013] A second aspect of the invention provides an apparatus comprising: an isolator according to a first aspect of the invention; and a conductive conduit, wherein the conductive conduit is arranged to pass through an orifice of the isolator.

[0014] A third aspect of the invention provides an isolation system comprising: an isolator according to a first aspect of the invention; a plurality of first bolts, wherein each of the plurality of first bolts is positioned in a countersunk hole of a corresponding first attachment point of a plurality of first attachment points of the isolator; and a plurality of second bolts, wherein each of the plurality of second bolts is positioned in a countersunk hole of a corresponding second attachment point of a plurality of second attachment points of the isolator.

[0015] Optionally, wherein at least one of the plurality of first bolts and the plurality of second bolts is conductive, the system includes a non-conductive sealant covering the head of at least one of the plurality of first bolts and the plurality of second bolts to seal the head of each bolt in the corresponding countersunk hole of each bolt.

[0016] Optionally, the isolation system includes a seal located in a recess of the isolator, the seal surrounding the outer wall of the orifice.

[0017] A fourth aspect of the invention provides a method for isolating a conductive internal panel or an aircraft fuel tank from a conductive conduit passing through the panel, the method comprising: passing the conduit through a tube of a non-conductive isolator; passing the tube through an opening in the panel; rigidly attaching the isolator to a conduit fitting fixed to the conduit; and rigidly attaching the isolator to the panel.

[0018] Optionally, the method includes: rigidly attaching the isolator to a pipe fitting fixed to a pipe using a conductive first fastener; electrically insulating the first fastener from the panel; rigidly attaching the isolator to the panel using a conductive second fastener; and electrically insulating the second fastener from the pipe.

[0019] Optionally, the method includes providing a seal between the isolator and the panel. Optionally, the seal is a liquid gasket.

[0020] A fifth aspect of the present invention provides an aircraft comprising: an isolator according to a first aspect of the present invention, a device according to a second aspect of the present invention, or an isolation system according to a third aspect of the present invention. Attached Figure Description

[0021] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, wherein:

[0022] Figure 1 A schematic isometric view of an isolator according to an embodiment of the present invention is shown;

[0023] Figure 2 A schematic cross-sectional view of an isolation system according to an embodiment of the present invention is shown, the isolation system comprising... Figure 1 isolators;

[0024] Figure 3 This is a flowchart illustrating a method according to an embodiment of the present invention; and

[0025] Figure 4 A schematic top view of an aircraft according to an embodiment of the present invention is shown. Detailed Implementation

[0026] Static electricity may accumulate in an aircraft's fuel tank, and / or the aircraft may be struck by lightning. In some aircraft, panels and pipes comprise or are formed of conductive materials and can therefore carry electric current. Therefore, isolating the panels from the pipes may be beneficial to prevent current from flowing between them.

[0027] Figure 1 An isometric view of an isolator 100 according to an embodiment of the present invention is shown. The isolator 100 is used for an aircraft fuel tank and is configured to separate the conductive inner panel of the fuel tank from conductive pipes passing through the panel.

[0028] The isolator 100 includes: a plurality of first attachment points 110 for attaching the isolator 100 to a panel; a plurality of second attachment points 120 for attaching the isolator 100 to a conduit; and an orifice 130 defined by an outer wall 140 and extending from a first side 102 of the isolator 100 to a second side 104 of the isolator 100. The orifice 130 is configured to receive a conduit in use.

[0029] In some embodiments, the outer wall 140 of the orifice 130 extends outward from the first side 102 of the isolator 100 to form a tube. This tube is configured to pass through a panel during use. In some embodiments, the outer wall 140 extends from the first side 102 of the isolator 100 by a distance greater than the thickness of the panel. The length of the tube is greater than the thickness of the isolator 100. That is, the length of the tube is greater than the distance between the first side 102 and the second side 104 of the isolator 100.

[0030] In some embodiments, a plurality of first attachment points 110 and a plurality of second attachment points 120 are positioned on a flange 106 extending from the outer wall 140 of the aperture 130. The flange 106 may define a first side 102 and a second side 104 of the isolator 100. Figure 1 The flange 106 of the isolator 100 shown is beveled around the first attachment point 110 and the second attachment point 120. This helps to reduce the size of the isolator 100 and thus its weight.

[0031] In some embodiments, the first attachment point 110 is configured to receive fasteners (not shown) for securing the isolator to a panel and / or the second attachment point 120 may be configured to receive fasteners (not shown) for securing the isolator to a conduit.

[0032] In some embodiments, the first attachment point 110 is positioned around the orifice 130 to align with a corresponding panel orifice (not shown) in the panel. In some embodiments, the second attachment point 120 is positioned around the orifice 130 to align with a corresponding fitting orifice (not shown) in a pipe fitting fixed to a pipe. Figure 1 The isolator 100 shown has three first attachment points 110 and three second attachment points 120, each first attachment point 110 being located at a first radial distance from the orifice 130, and each second attachment point 120 being located at a second radial distance from the orifice 130. In some embodiments, the first radial distance and the second radial distance are the same.

[0033] In some embodiments, the isolator includes two or more first attachment points 110. In some embodiments, the isolator includes two or more second attachment points 120. Figure 1 The isolator 100 shown is alternately spaced between a first attachment point 110 and a second attachment point 120, such that the attachment points 110 and 120 are equidistantly spaced around the orifice 130. This configuration helps to distribute the load evenly through the isolator 100 during use, thereby helping to reduce the stress on the isolator 100 during use.

[0034] In some implementations, the first attachment point 110 is oriented in the opposite direction to the second attachment point 120. Figure 1 Each of the first attachment points 110 of the isolator 100 shown includes a first countersunk hole that extends from a wider end of the first countersunk hole at a second side 104 of the isolator 100 to a narrower end of the first countersunk hole at a first side 102 of the isolator 100. Figure 1Each of the second attachment points 120 of the isolator 100 shown includes a second countersunk hole extending from a wider end of the second countersunk hole at a first side 102 of the isolator 100 to a narrower end of the second countersunk hole at a second side 104 of the isolator 100. The wider end 122 of the countersunk hole extends from the first side 102 of the isolator 100. In some embodiments, the narrower ends of the first and / or second countersunk holes are threaded and configured to receive a corresponding threaded bolt.

[0035] In other embodiments, the first attachment point 110 and / or the second attachment point 120 may be any other shape suitable for attaching the isolator 100 to the panel and the pipe, respectively.

[0036] Figure 1 The isolator 100 shown includes a first recess 150 located on a first side 102 of the isolator 100. The first recess 150 extends around the outer wall 140 of the orifice 130 and is configured to receive a first seal (not shown). In other embodiments, the first recess 150 may be omitted. In some embodiments, the isolator 100 includes a second recess 160 (e.g., Figure 2 As shown, the second groove 160 is located on the second side 104 of the isolator 100. The second groove 160 extends around the orifice 130 and is configured to receive the second seal. In other embodiments, the second groove 160 may be omitted. In use, the first and second seals can help prevent fuel from passing from one side of the panel to the other and can help further isolate the panel from the conduit.

[0037] Isolator 100 comprises a non-conductive material. In some embodiments, the non-conductive material does not react with aircraft fuel or hydraulic fluid. This material helps prevent premature degradation of isolator 100 during use and can help prevent fuel contamination due to degradation of isolator 100. In some embodiments, isolator 100 comprises another material coated with a non-conductive material. In other embodiments, isolator 100 is formed solely of a non-conductive material, for example, isolator 100 is machined from a bulk of non-conductive material or isolator 100 is molded from a non-conductive material. In some embodiments, isolator 100 comprises a single component. In other embodiments, isolator 100 is formed of two or more components rigidly held together, for example, by mechanical fastening or by chemical means such as adhesives. In some embodiments, isolator 100 is formed of a chemically inert material such as nylon.

[0038] Figure 2A schematic cross-sectional view of an isolation system 10 according to an embodiment of the present invention is shown. The isolation system 10 includes an isolator 100 according to an embodiment of the present invention, for example... Figure 1 The isolator 100 is shown in the diagram. The isolation system 10 also includes a plurality of first bolts 12 and a plurality of second bolts 16. Each of the plurality of first bolts 12 is positioned in a countersunk hole of a corresponding first attachment point 110 of the isolator 100. Each of the plurality of second bolts 16 is positioned in a countersunk hole of a corresponding second attachment point 120 of the isolator 100. Each of the plurality of first bolts 12 is held in place by a corresponding first nut 14. Each of the plurality of second bolts 16 is held in place by a corresponding second nut 18.

[0039] Figure 2 An isolation system 10 in use is shown. Specifically, an isolator 100 is positioned within the aircraft's fuel tank. The isolator 100 is secured to a pipe fitting 6 through which the pipe 4 passes by a plurality of second bolts 16. In this embodiment, both the pipe fitting 6 and the pipe 4 are conductive. The outer wall 140 of the isolator 100 extends through an isolator aperture 3 in a panel 1. The panel 1 extends through the aircraft's fuel tank. The isolator 100 is secured to the panel 1 by a plurality of first bolts 12. In some embodiments, the panel 1 is the inner wall of the fuel tank, and different isolators are used at the intersection between the pipe 4 and the outer wall of the fuel tank.

[0040] As in Figure 2 As can be seen, the outer wall 140 of the isolator 100 is positioned between the panel 1 and the pipe fitting 6 during use. In some embodiments, such as when the pipe fitting 6 is conductive, the outer wall 140 is configured to extend from the first side 102 of the isolator 100 by a distance exceeding the width of the panel 1, and extends an additional distance that prevents the formation of an electric arc between the panel 1 and the pipe fitting 6 or pipe 4 (see, for example, [reference needed]). Figure 2 (dashed line 50 in the text). In some embodiments, the flange 106 of the isolator 100 has sufficient features to help prevent arcing between the panel 1 and the pipe fitting 6 (see, for example, see...). Figure 2 The thickness of the dashed line (60) in the middle.

[0041] The first attachment point 110 is positioned on the flange 106 of the isolator 100 to align with a corresponding panel aperture 2 in the panel 1. The second attachment point 120 is positioned on the flange 106 of the isolator 100 to align with a corresponding fitting aperture 7 in the pipe fitting 6. In some embodiments, the isolator 100 is configured such that the first attachment point 110 is located at a radial distance from the outer wall 140 sufficient to help prevent arcing between the plurality of first bolts 12 and the pipe fitting 6 or pipe 4 (e.g., see...). Figure 2 (70 in the dashed line).

[0042] When the plurality of first bolts 12 and the plurality of second bolts 16 are positioned in their respective countersunk holes, a corresponding void 13, 17 is formed around the head of each bolt. In some embodiments, at least one of the plurality of first bolts 12 and the plurality of second bolts 16 is conductive. In such embodiments, system 10 includes a non-conductive sealant (not shown) that covers the head of at least one of the plurality of first bolts 12 and the plurality of second bolts 16 to seal the head of each bolt in the corresponding countersunk hole of each bolt. In some embodiments, the sealant fills the voids 13, 17. In some embodiments, the sealant is formed of a chemically inert material. In use, the sealant helps to prevent the formation of electric arcs between the first bolt 12 and the pipe 4 and / or pipe fitting 6 and between the second bolt 16 and the panel 1 (e.g., see...). Figure 2 (70 in the dashed line).

[0043] Figure 2 The isolation system 10 shown includes an isolator 100, which includes a first recess 150 located on a first side 102 of the isolator 100 and surrounding an outer wall 140. The isolation system 10 includes a first seal 29 located in the first recess 150 of the isolator 100. The first seal 29 surrounds the outer wall 140 of the isolator 100. By way of example only, the first seal 29 is an O-ring. In use, as... Figure 2 As shown, the first seal 29 is positioned between the isolator 100 and the panel 1. The first seal 29 also helps to isolate the panel 1 from the conduit 4. The first seal 29 also helps to prevent fuel leakage through the panel orifice 3.

[0044] In some embodiments, the isolation system 10 includes an isolator 100 that does not include a first recess 150. In such embodiments, a liquid sealant or liquid gasket (not shown) may be disposed between the panel 1 and a first side 102 of the isolator 100. The liquid sealant also helps to isolate the panel 1 from the conduit 4.

[0045] Figure 2 The isolation system 10 shown includes an isolator 100, which includes a second recess 160 located on a second side 104 of the isolator 100 and surrounding an orifice 130. The isolation system 10 includes a second seal 30 located in the second recess 160 of the isolator 100. The second seal 30 surrounds the orifice 130 on the second side 104 of the isolator 100. By way of example only, the second seal 30 is an O-ring. In use, as... Figure 2As shown, the second seal 30 is positioned between the isolator 100 and the pipe fitting 4. The second seal 30 also helps to isolate the panel 1 from the pipe 4. The second seal 30 also helps to prevent fuel leakage through the panel orifice 3.

[0046] In some embodiments, the isolation system 10 includes an isolator 100 that does not include a second recess 160. In such embodiments, a liquid sealant or liquid gasket (not shown) may be provided between the pipe fitting 4 and the second side 104 of the isolator 100. The liquid sealant also helps to isolate the panel 1 from the pipe 4.

[0047] Figure 3 A flowchart of a method 300 for isolating a conductive internal panel or aircraft fuel tank from a conductive conduit passing through the panel, according to an embodiment of the present invention, is shown. Method 300 includes: passing the conduit through a tube 310 of a non-conductive material isolator; passing the tube through an orifice in the panel 320; rigidly attaching the isolator 330 to a conduit fitting fixed to the conduit; and rigidly attaching the isolator 340 to the panel.

[0048] In some embodiments, the isolator is an isolator 100 according to an embodiment of the present invention.

[0049] In some embodiments, rigid attachment 330 includes removably and rigidly attaching the isolator to a pipe fitting fixed to a pipe. In some embodiments, rigid attachment 340 includes removably and rigidly attaching the isolator to a panel. For example, the isolator can be attached to both the pipe fitting and the panel using fasteners.

[0050] In some embodiments, rigid attachment 330 includes rigidly attaching the isolator to the pipe fitting using a conductive first fastener, and the method includes electrically insulating the first fastener from the panel 350. In some embodiments, rigid attachment 340 includes rigidly attaching the isolator to the panel using a conductive second fastener, and the method includes electrically insulating the second fastener from the pipe 360. In some embodiments, electrical insulation 350, 360 can be achieved by applying a non-conductive sealant to the first and second fasteners.

[0051] In some embodiments, the method includes providing a 370 seal between the isolator and the panel. In some embodiments, the seal may be disposed in a recess in the isolator, for example... Figure 2 The isolator 100 shown has a first recess 150 and / or a second recess 160. In other embodiments, the seal may be a liquid gasket between the surface of the panel and the adjacent surface of the isolator and / or between the surface of the pipe fitting and the isolator.

[0052] Figure 4 A schematic top view of an aircraft 400 according to an embodiment of the present invention is shown. The aircraft 400 includes a fuselage 410 and a wing 420. In some embodiments, the wing 420 is formed of a non-conductive material such as a carbon composite material. In other embodiments, the wing 420 is formed of a non-conductive material such as a carbon composite material. In other aircraft, the wing is formed of a conductive material and may not require an isolator according to the present invention because the wing itself can dissipate current.

[0053] In some embodiments, the aircraft fuel tank is located within the wing 420. In some embodiments, the aircraft 400 includes one or more isolators 100 according to the invention. In some embodiments, one or more isolators 100 are located within the aircraft fuel tank and are fixed to one or more corresponding internal panels 1 of the aircraft fuel tank. In some embodiments, the aircraft 400 includes one or more isolation systems 10 according to embodiments of the invention. One or more isolation systems 10 are fixed to one or more corresponding internal panels 1 of the aircraft fuel tank.

[0054] It should be noted that, unless otherwise expressly stated, the term “or” as used herein should be interpreted as meaning “and / or”.

[0055] The above embodiments should be understood as non-limiting illustrative examples of how the invention and its various aspects can be implemented. Other examples of the invention are contemplated. It should be understood that any feature described with respect to any embodiment can be used alone or in combination with other described features, and can also be used in combination with one or more features of any other embodiment or any other combination of any other means. Furthermore, equivalents and modifications not described above may be employed without departing from the scope of the invention as defined by the appended claims.

Claims

1. An isolator for an aircraft fuel tank, the isolator being configured to separate a conductive internal panel of the fuel tank from a conductive conduit passing through the panel, the isolator comprising: A plurality of first attachment points, the plurality of first attachment points being used to attach the isolator to the panel; A plurality of second attachment points, the plurality of second attachment points being used to attach the isolator to the conduit; as well as An orifice, defined by an outer wall and extending from a first side of the isolator to a second side of the isolator, is configured to receive the conduit during use. The isolator comprises a non-conductive material.

2. The isolator according to claim 1, wherein, The outer wall of the orifice extends outward from the first side of the isolator to form a tube, wherein the tube is configured to pass through the panel during use.

3. The isolator according to claim 1 or 2, wherein, The plurality of first attachment points and the plurality of second attachment points are positioned on a flange extending from the outer wall of the orifice.

4. The isolator according to claim 1 or 2, wherein, The first attachment point includes a countersunk hole extending from the second side of the isolator to the first side of the isolator. The wider end of the countersunk hole extends from the second side of the isolator.

5. The isolator according to claim 1 or 2, wherein, The first attachment point is positioned around the aperture to align with the corresponding panel aperture in the panel.

6. The isolator according to claim 1 or 2, wherein, The second attachment point includes a countersunk hole extending from the first side of the isolator to the second side of the isolator. The wider end of the countersunk hole extends from the first side of the isolator.

7. The isolator according to claim 1 or 2, wherein, The second attachment point is positioned around the orifice to align with the corresponding fitting orifice in the pipe fitting fixed to the pipe.

8. The isolator according to claim 1 or 2, comprising a groove on the first side and / or the second side of the isolator, the groove extending around the outer wall of the orifice and configured to receive a seal.

9. The isolator according to claim 1 or 2, wherein the isolator is formed of a chemically inert material.

10. An apparatus comprising: The isolator according to any one of claims 1 to 9; as well as conductive pipes The conductive conduit is arranged to pass through the orifice of the isolator.

11. An isolation system, comprising: The isolator according to any one of the preceding claims; A plurality of first bolts, wherein each of the plurality of first bolts is positioned in a countersunk hole of a corresponding first attachment point among the plurality of first attachment points of the isolator; and A plurality of second bolts, wherein each of the plurality of second bolts is positioned in a countersunk hole of a corresponding second attachment point among the plurality of second attachment points of the isolator.

12. The isolation system according to claim 11, wherein, At least one of the plurality of first bolts and the plurality of second bolts is conductive. The system includes a non-conductive sealant that covers the head of at least one of the plurality of first bolts and the plurality of second bolts to seal the head of each bolt in the corresponding countersunk hole of each bolt.

13. The system according to claim 11 or claim 12, wherein, The isolator includes a groove located on a first side and / or a second side of the isolator, the groove extending around the outer wall of the orifice, and the system includes a seal located in the groove, the seal surrounding the outer wall of the orifice.

14. A method for isolating a conductive internal panel of an aircraft fuel tank from a conductive conduit passing through the panel, the method comprising: The pipe passes through the tube of the non-conductive material insulator; Pass the tube through the opening in the panel; The isolator is rigidly attached to a pipe fitting that is fixed to the pipe; as well as The isolator is rigidly attached to the panel. The isolator is an isolator according to any one of claims 1 to 9.

15. The method of claim 14, comprising: The isolator is rigidly attached to the pipe fitting fixed to the pipe using a conductive first fastener; The first fastener is electrically insulated from the panel; The isolator is rigidly attached to the panel using a conductive second fastener; as well as This makes the second fastener electrically insulated from the pipe.

16. The method of claim 14 or 15, further comprising providing a seal between the isolator and the panel.

17. The method according to claim 16, wherein, The sealing element is a liquid sealing gasket.

18. An aircraft comprising: The isolator according to any one of claims 1 to 9; or The isolation system according to any one of claims 11 to 13.

19. The aircraft of claim 18, comprising a wing formed of a non-conductive material.

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