The disclosure relates generally to feedthrough devices, and more particularly to a device for accommodating one or more feedthrough members through a wall such as a firewall of an aircraft.
Gas turbine engines typically include one or more firewalls separating relatively cool non-fire zones from an ignition or fire zone that can include a combustor or other relatively hot section of the gas turbine engine. A firewall may also be disposed on an airframe to protect an aircraft or other mobile platform to which the gas turbine engine is mounted. Despite the fire and non-fire zones being separated by firewalls, engine and/or aircraft systems require electric and/or fluid communication across the firewalls. The electric and/or fluid communication can include electric wires, fuel lines, air lines and oil lines for example. The electric and/or fluid communication is typically established by way of suitable feedthrough systems. Existing feedthrough systems across firewalls can be relatively cumbersome and can also complicate maintenance tasks. Improvement is desirable.
In one aspect, the disclosure describes an aircraft firewall feedthrough device for accommodating a feedthrough member through an aperture of a firewall of an aircraft. The aircraft firewall feedthrough device comprises:
a plate configured to be attached to the firewall, the plate including: a feedthrough aperture; a first side for facing toward the firewall; and a second side opposite the first side;
a first tubular portion extending from the first side of the plate;
a second tubular portion extending from the second side of the plate, wherein the first tubular portion, the second tubular portion and the feedthrough aperture cooperatively defining a through passage for accommodating the feedthrough member through the aperture of the firewall; and
a grommet retained inside the through passage, the grommet including a hole for accommodating the feedthrough member through the grommet.
In another aspect, the disclosure describes an aircraft firewall feedthrough device for accommodating a wire harness through an aperture of a firewall of an aircraft. The aircraft firewall feedthrough device comprises:
a tube defining an internal through passage for accommodating the wire harness through the aperture of the firewall;
a flange projecting outwardly from the tube and configured to be attached to the firewall, wherein a first portion of the tube is disposed on a first side of the flange facing toward the firewall and a second portion of the tube is disposed on a second side of the flange opposite the first side; and
a grommet retained inside the tube, the grommet including a plurality of holes for accommodating respective wires or wire groups of the wire harness.
In a further aspect, the disclosure describes an aircraft engine comprising:
a firewall configured to hinder the spread of fire from a first part of the gas turbine engine to a second part of the gas turbine engine, the firewall having an aperture therethrough;
a feedthrough member extending from the first part to the second part of the gas turbine engine via the aperture of the firewall; and
an aircraft firewall feedthrough device forming a seal between the feedthrough member and the firewall, the aircraft firewall feedthrough device including:
a plate attached to the firewall, the plate including: a feedthrough aperture; a first side facing toward the firewall; and a second side opposing the first side;
a first tubular portion extending from the first side of the plate;
a second tubular portion extending from the second side of the plate, the first tubular portion, the second tubular portion and the feedthrough aperture cooperatively defining a through passage for accommodating the feedthrough member through the aperture of the firewall; and
a grommet retained inside the through passage, the grommet including a hole for accommodating the feedthrough member through the grommet.
Further details of these and other aspects of the subject matter of this application will be apparent from the detailed description included below and the drawings.
Reference is now made to the accompanying drawings, in which:
The following disclosure describes devices for (e.g., sealingly) accommodating one or more feedthrough members through an aperture of a wall. In some embodiments, the devices described herein may provide suitable sealing between the wall and the feedthrough members, and may be used to accommodate feedthrough members through firewalls of aircraft engines, aircraft and other mobile platforms, or other suitable applications. For example, some embodiments of the device may provide suitable sealing performance to hinder or prevent flame and/or vapor migration from one side of a firewall to the other. In some embodiments, the devices disclosed herein may have a relatively simple and economical construction that can also facilitate installation and maintenance tasks. Aspects of various embodiments are described through reference to the drawings.
The terms “connected”, “attached” or “coupled” may include both direct connection, attachment or coupling (in which two elements contact each other) and indirect connection, attachment or coupling (in which at least one additional element is disposed between the two elements).
The term “substantially” as used herein may be applied to modify any quantitative representation which could permissibly vary without resulting in a change in the basic function to which it is related.
Gas turbine engine 10 may be an aircraft engine of a type preferably provided for use in subsonic flight to drive a load such as propeller 14 via low-pressure shaft 16 (sometimes called “power shaft”) coupled to low-pressure turbine 18. Low-pressure turbine 18 and low-pressure shaft 16 may be part of a first spool of gas turbine engine 10 known as a low-pressure spool. Gas turbine engine 10 may include a second or high-pressure spool including high-pressure turbine 20, (e.g., multistage) compressor 22 and high-pressure shaft 24.
Compressor 22 may draw ambient air into gas turbine engine 10 via annular radial air inlet duct 26, increase the pressure of the drawn air and deliver the pressurized air to combustor 28 where the pressurized air is mixed with fuel and ignited for generating an annular stream of hot combustion gas. High-pressure turbine 20 may extract energy from the hot expanding combustion gas and thereby drive compressor 22. The hot combustion gases leaving high-pressure turbine 20 may be accelerated as it further expands, flows through and drives low pressure turbine 18. The combustion gas may then exit gas turbine engine 10 via exhaust duct 30.
Gas turbine engine 10 may include one or more firewalls 32 (referred hereinafter in the singular) having one or more feedthrough members 34 (shown in
Device 12 may include plate 38 configured to be attached to firewall 32 via one or more bolts 40 and/or other suitable means. Depending on the specific environmental conditions in which device 12 is installed, plate 38 may be made from a suitable metallic material (e.g., steel, aluminum, titanium), polymeric material or fiber-reinforced composite material. When attached to firewall 32, a suitable metallic material having acceptable fire/heat resistance may be used. Bolts 40 may extend through fastener holes formed in plate 38 and be threaded into firewall 32 in order to secure plate 38 to firewall 32.
In some applications, plate 38 may be attached directly to firewall 32. Alternatively, in some embodiments, gasket 42 may be disposed and compressed between plate 38 and firewall 32 in a sandwich configuration in order to form a seal between firewall 32 and a side of plate 38 facing toward firewall 32. Gasket 42 may be made of a material that is softer than plate 38 to permit some deformation of gasket 42 when compressed between plate 38 and firewall 32. Gasket 42 may be made from any material suitable for the applicable environmental conditions. In various embodiments, gasket 42 may be made from rubber, silicone, metal, cork, felt, neoprene, nitrile rubber, fiberglass, polytetrafluoroethylene (otherwise known as PTFE or Teflon) or a plastic polymer (such as polychlorotrifluoroethylene) for example. In various embodiments, gasket 42 may be provided in sheet form and cut to a suitable shape and size to provide a seal surrounding aperture 36 extending through firewall 32. Alternatively or in addition, a suitable sealant such as room temperature vulcanizing (RTV) silicone sealant may be used to provide a seal between plate 38 and firewall 32.
Plate 38 may include feedthrough aperture 44 extending therethrough for communication with aperture 36 of firewall 32. Device 12 may include first tubular portion 46A extending from a first side of plate 38 and second tubular portion 46B extending from a second side of plate 38 opposite the first side. Plate 38 may have the form of a flange projecting (e.g., radially) outwardly from a tube cooperatively defined by first tubular portion 46A and second tubular portion 46B. Plate 38 may extend partially or fully around such tube. First tubular portion 46A, second tubular portion 46B and feedthrough aperture 44 may cooperatively define a through passage 48 for accommodating feedthrough member(s) 34. Device 12 may also include one or more grommets 50A, 50B (shown in
When device 12 is installed on firewall 32, first tubular portion 46A may extend through firewall 32 and second tubular portion 46B may extend away from firewall 32. First tubular portion 46A may extend from plate 38 by a distance L1 and second tubular portion 46B may extend from plate 38 by a distance L2 where distances L1 and L2 are measured along central axis CA of passage 48. Central axis CA may also be a longitudinal axis of passage 48. Central axis CA may intersect or be offset from a central axis of aperture 36 through firewall 32. In various embodiments, distances L1 and L2 may be different or substantially identical depending on specific installation constraints or requirements.
In some embodiments, central axis CA of passage 48 may be oblique to a normal N of plate 38. In various embodiments, central axis CA of passage 48 may be oriented at a non-zero angle a of normal N. In some embodiments, first tubular portion 46A and second tubular portion 46B may be substantially coaxial. In various embodiments, each of tubular portions 46A, 46B may have a circular, square, oval, rectangular or other cross-sectional profile. In various embodiments, plate 38 may be flat, curved or embossed to accommodate firewalls 32 of various shapes including flat/planar and dome-shaped for example. In various embodiments, tubular portions 46A, 46B may be substantially straight or may be curved to defined a curved passage 48 for accommodating one or more feedthrough members 34.
In some embodiments, first tubular portion 46A and second tubular portion 46B may be separate tubing pieces that are assembled with plate 38 via welding, brazing or other suitable method. In some embodiments, first tubular portion 46A and second tubular portion 46B may be part of a single piece of tubing (i.e., of a unitary construction) that extends through plate 38 and that is welded to plate 38 at location W for example. Alternatively, plate 38 and tubular portions 46A, 46B may be cast and/or machined, produced by additive manufacturing or injection molding depending on the material used. In some embodiments, plate 38 and tubular portions 46A, 46B may be made from the same type of metallic material.
The embodiment shown illustrates a plurality of feedthrough members 34 extending through both grommets 50A, 50B. However, embodiments having a sole feedthrough member 34 are also contemplated. In an electrical feedthrough application, each feedthrough member 34 may be a single wire or multiple (e.g., two, three or more) wires grouped together (e.g., cable or multiple cables), which may or may not be part of a larger wire harness for example.
In some embodiments, outer surfaces of grommets 50A, 50B may be tight-fitting (e.g., provide an interference fit) with the inside of tubular portions 46A, 46B. Similarly, inner surfaces of holes 56 of grommets 50A, 50B may be loose or tight-fitting (e.g., provide an interference fit) around respective feedthrough members 34 and may provide some sealing function to prevent or hinder the entry of dirt, air, water, etc. through firewall 32 via passage 48. In some embodiments, one or more circlips, also known as C-clips, may be used to retain one or more feedthrough members 34 and/or grommets 50A, 50B with respect to tubular portions 46A, 46B.
In some situations the use of one or more grommets 50A, 50B may provide acceptable sealing function. However, in some applications, some supplemental sealing may be required to provide an acceptable sealing performance. In some firewall applications, it may be desirable to provide a enhanced sealing performance to prevent flame and/or vapor migration from one side of firewall 32 to the other. Such supplemental sealing may be provided by way of sealant 58 applied to one or both sides of grommet 50A and/or to one or both sides of grommet 50B to provide supplemental sealing between feedthough members 34 and the inside of tubular portions 46A, 46B. In some embodiments, sealant 58 may be poured inside of tubular portion 46A, 46B in a liquid state so as to flow around feedthrough members 34, fill gaps and free holes 56 if applicable, and then allowed to cure and form a seal. In some embodiments, sealant 58 may be RTV silicone applied as a liquid silicone compound that cures at room temperature to form a flexible rubber. In various embodiments, sealant 58 may be an adhesive sealant, moulding rubber or electronic encapsulating compound. Sealant 58 may be applied to one or both axial faces of one or more grommet(s) 50A, 50B. In some embodiments, sealant 58 may provide a suitable vapor barrier.
In some embodiments of device 12, second tubular portion 46B may have second anchoring feature 60B for engagement with jacket portion 52B for facilitating the attachment of jacket portion 52B (shown in
During installation, jacket portion 52B (e.g., overbraid) may be slipped over second tubular portion 46B and over second anchoring feature 60, and secured to second anchoring feature 60 using a cable tie, clamp, heat shrink tube or tape. It is understood that first tubular portion 46A may also have first anchoring feature 60A (shown in
Aircraft firewall feedthrough device 12 may be integrated into a wire harness and at the proper location along the wire harness, and then simply attached to firewall 32 at the time of installing the wire harness into engine 10 or other system.
During assembly of a wire harness for example, and in reference to
The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. For example, it is understood that some embodiments of aircraft firewall feedthrough devices 12, 120, 220, 320, 420 and 520 may be suitable for firewall feedthrough applications in aircraft (e.g., gas turbine) engines and that some embodiments of aircraft firewall feedthrough devices 12, 120, 220, 320, 420 and 520 may be suitable for other (e.g., less stringent) feedthrough applications. Yet further modifications could be implemented by a person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology.