The present disclosure relates to ignition-suppressing devices for shielding fasteners in aircraft fuel tanks.
Conventionally, metal fasteners in a composite aircraft fuel tank are isolated from the fuel volume by sealant and/or seal caps. The sealant and/or seal caps is/are physically and/or electrically separate the metal fasteners from the fuel volume and is/are configured to contain any ignition hazard. Installation of sealant and/or seal caps requires labor-intensive steps, such as solvent cleaning, brush coating, multiple hand-application steps, curing, and inspection. The associated installation time and inspection time increase the cost of aircraft. Furthermore, many fasteners are located sufficiently close to other fasteners so that seal caps must be custom trimmed to fit over the respective fasteners without physically interfering with adjacent fasteners or seal caps. Custom trimming further increases manufacturing lead time, and thus, cost.
Accordingly, apparatuses and methods, intended to address at least the above-identified concerns, would find utility.
The following is a non-exhaustive list of examples of the subject matter, disclosed herein.
Disclosed herein is an ignition-suppressing device for shielding fasteners. The ignition-suppressing device comprises a ribbon and receptacles that are spaced apart from one another along the ribbon.
The ignition-suppressing device therefor is configured to be installed over fasteners within an aircraft fuel tank, with the fasteners extending into respective ones of the receptacles for suppression of ignition events, such as a result of lightning strikes on an aircraft. Having multiple receptacles spaced apart along the ribbon enables a supply of the receptacles to be easily dispensed during manufacture of the aircraft fuel tank, significantly reducing the time involved compared to installation of individual rigid caps in aircraft fuel tanks.
Also disclosed herein is an aircraft fuel tank. The aircraft fuel tank comprises an ignition-suppressing device, a wall, and fasteners, extending inside the aircraft fuel tank from the wall. Each of the fasteners is received by a respective one of the receptacles of the ignition-suppressing device.
Also disclosed herein is a method of installing, in an aircraft fuel tank, an ignition-suppressing device. The method comprises positioning each of the fasteners, extending inside the aircraft fuel tank from the wall of the aircraft fuel tank, within a respective one of the receptacles of the ignition-suppressing device. The method further comprises coupling the ignition-suppressing device to the wall.
Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and where like reference characters designate the same or similar parts throughout the several views. In the drawings:
In
In
In the following description, numerous specific details are set forth to provide a thorough understanding of the disclosed concepts, which may be practiced without some or all of these particulars. In other instances, details of known devices and/or processes have been omitted to avoid unnecessarily obscuring the disclosure. While some concepts will be described in conjunction with specific examples, it will be understood that these examples are not intended to be limiting.
Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, e.g., a “second” item does not require or preclude the existence of, e.g., a “first” or lower-numbered item, and/or, e.g., a “third” or higher-numbered item.
Reference herein to “one or more examples” means that one or more feature, structure, or characteristic described in connection with the example is included in at least one implementation. The phrase “one or more examples” in various places in the specification may or may not be referring to the same example.
As used herein, a system, apparatus, structure, article, element, component, or hardware “configured to” perform a specified function is indeed capable of performing the specified function without any alteration, rather than merely having potential to perform the specified function after further modification. In other words, the system, apparatus, structure, article, element, component, or hardware “configured to” perform a specified function is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing the specified function. As used herein, “configured to” denotes existing characteristics of a system, apparatus, structure, article, element, component, or hardware which enable the system, apparatus, structure, article, element, component, or hardware to perform the specified function without further modification. For purposes of this disclosure, a system, apparatus, structure, article, element, component, or hardware described as being “configured to” perform a particular function may additionally or alternatively be described as being “adapted to” and/or as being “operative to” perform that function.
Illustrative, non-exhaustive examples of the subject matter, disclosed herein, are provided below.
Referring generally to
Ignition-suppressing device 100 therefor is configured to be installed over fasteners 106 within aircraft fuel tank 108, with fasteners 106 extending into respective ones of receptacles 104 for suppression of ignition events, such as a result of lightning strikes on an aircraft. Having multiple ones of receptacles 104 spaced apart along ribbon 102 enables a supply of receptacles 104 to be easily dispensed during manufacture of aircraft fuel tank 108, significantly reducing the time involved compared to installation of individual rigid caps in aircraft fuel tanks.
In one or more examples, ignition-suppressing device 100 is constructed with a specific spacing of receptacles 104 corresponding to a specific spacing of fasteners 106 within aircraft fuel tank 108. Accordingly, in such examples, ignition-suppressing device 100 is dispensed and installed without the need for alteration of ignition-suppressing device 100, further reducing the time involved compared to installation of individual rigid caps.
In one or more examples, ribbon 102 and/or ignition-suppressing device 100 is described as a strip.
In one or more examples, as illustrated in
In one or more examples, receptacles 104 and ribbon 102 are constructed of any materials to perform the functions thereof discussed herein, including materials that are compatible with aircraft fuel.
Referring generally to
By being constructed of the same material as a unitary structure, ignition-suppressing device 100 is easily manufactured.
As used herein, “unitary structure” simply means that ribbon 102 and receptacles 104 are unitary in nature and are not constructed separately and subsequently coupled together. “Unitary structure” does not preclude the material having multiple layers or fibers woven together, for example.
Referring generally to
By being permeable to gases, following an electrical event, resulting in combustion gases within receptacles 104, receptacles 104 enable the combustion gases to leak out of the receptacles into the fuel tank. By being permeable to gases and permeable to aircraft fuel, even if fuel vapor or liquid fuel is present in a receptacle during an electrical event, the receptacle will suppress any combustion of the fuel vapor or liquid fuel. By being impermeable to aircraft fuel, receptacles 104 not only contain the ejection of hot particles and/or gas that may result from lightning strikes or other electrical events, but also they keep aircraft fuel, which under certain conditions will vaporize and be combustible, out of receptacles 104.
In one or more examples, material that is both permeable to gases and impermeable to liquids includes woven and non-woven polymer fabrics, including stretched polytetrafluoroethylene (PTFE), such as sold under the GORE-TEX™ brand.
In one or more examples, receptacles 104 and/or ribbon 102 are constructed of multiple layers of material. In one or more such examples, a batting, such as of nylon felt, may be positioned between two outer layers of material, such as PTFE fabric.
Referring generally to
Adhesive regions 110 couple ignition-suppressing device 100 to aircraft fuel tank 108.
In one or more examples, at least a subset of adhesive regions 110 is positioned to adhere ignition-suppressing device 100 to wall 114 of aircraft fuel tank 108. In one or more additional examples, as discussed herein, at least another subset of adhesive regions 110 is positioned to adhere ignition-suppressing device 100 to fasteners 106 extending from wall 114 of aircraft fuel tank 108.
In one or more examples, adhesive regions 110 comprises any suitable adhesive compatible with the material or materials from which ignition-suppressing device 100 is constructed, with the material or materials of wall 114 and/or fasteners 106 of aircraft fuel tank 108, and with aircraft fuel.
Referring generally to
Adhesive edge regions 120 couple ignition-suppressing device 100 to wall 114 of aircraft fuel tank 108 and seal receptacles 104 from the fuel in aircraft fuel tank 108.
Referring generally to
With adhesive edge regions 120, adhesive cross regions 122 create an enclosed space around each of receptacles 104. Accordingly, upon an electrical event, associated with a receptacle, an adjacent receptacle will not necessarily be impacted. That is, hot particles and/or combustion gases will not travel from one receptacle to another.
Referring generally to
Adhesive central regions 130 facilitate proper positioning of ignition-suppressing device 100 on wall 114 of aircraft fuel tank 108 during installation of ignition-suppressing device 100.
Also, as illustrated in
Referring generally to
Because adhesive central regions 130 cure faster than adhesive edge regions 120 and adhesive cross regions 122, ignition-suppressing device 100 is easily and properly positionable on wall 114 during installation, so that a long-term, stronger, and/or more chemically resistant bond subsequently can be established with adhesive edge regions 120 and adhesive cross regions 122 following initial placement of ignition-suppressing device 100.
Referring generally to
Adhesive fastener regions 124 are therefore positioned to ensure that receptacles 104, once operatively positioned over fasteners 106, remain in place during and subsequent to installation of ignition-suppressing device 100.
Referring generally to
Inclusion of a faster-curing portion enables receptacles 104 to be operatively positioned and retained over fasteners 106 during installation of ignition-suppressing device 100, while inclusion of a slower-curing portion enables a long-term bond between receptacles 104 and fasteners 106 following initial positioning of receptacles 104 over fasteners 106.
Examples of slower curing adhesives for use as adhesive edge regions 120, adhesive cross regions 122, and second adhesive portion 128 of adhesive fastener regions 124 include polysulfide sealants, such as such as a polyurethanes, polythioethers, manganese dioxide cured polysulfides, dichromate cured polysulfides, epoxy cured polythioethers, etc., and combinations thereof. Examples of faster curing adhesives for use as adhesive central regions 130 and first adhesive portion 126 of adhesive fastener regions 124 include structural acrylic, epoxy, etc.
Referring generally to
By first adhesive portion 126 and second adhesive portion 128 of adhesive fastener regions 124 being adjacent to each other on reverse side 103 of ignition-suppressing device 100, manufacturing of ignition-suppressing device 100 is facilitated, such as by utilization of two adjacent nozzles of adhesive for dispensing of the respective adhesives onto reverse side 103 of ignition-suppressing device 100.
The adhesive fastener region illustrated on the right side of
Referring generally to
By first adhesive portion 126 and second adhesive portion 128 of adhesive fastener regions 124 being concentric with each other on reverse side 103 of ignition-suppressing device 100, manufacturing of ignition-suppressing device 100 is facilitated, such as by utilization of a nozzle with concentric outlets for dispensing of the respective adhesives onto reverse side 103 of ignition-suppressing device 100.
The adhesive fastener region illustrated on the left side of
Referring generally to
As illustrated in
Referring generally to
Reverse-side release sheet 132 restricts premature curing of adhesive regions 110 on reverse side 103 and permits handling and storage of ignition-suppressing device 100.
In one or more examples, reverse-side release sheet 132 is an aluminum tape. In one or more examples, reverse-side release sheet 132 is a polymeric film.
Referring generally to
Obverse-side release sheet 133 restricts premature curing of adhesive regions 110 on obverse side 101 and permits handling and storage of ignition-suppressing device 100.
In one or more examples, obverse-side release sheet 133 is an aluminum tape. In one or more examples, obverse-side release sheet 133 is a polymeric film.
Referring generally to
Openings 135 enable obverse-side release sheet 133 to accommodate receptacles 104 that extend away from ribbon 102 in one or more examples.
In one or more examples, obverse-side release sheet 133 instead comprises multiple spaced-apart portions that are separately releasably coupled to ribbon 102 on obverse side 101 of ignition-suppressing device 100.
Referring generally to
Accordingly, during a lightning strike or other electrical event in which hot gases are formed within a receptacle or hot particles are ejected from a fastener or near a fastener, the receptacle will expand as a result of the increase in pressure within the receptacle. As a result, the forces associated with the electrical event will be dampened, and the integrity of the receptacle will be maintained and able to operatively perform during subsequent electrical events.
In addition, in one or more examples, as illustrated in
Referring generally to
The circular corrugations enable a greater increase in volume within receptacles 104 when an electrical event occurs. The circular corrugations also enable receptacles 104 to accommodate multiple sizes and/or shapes of fasteners 106.
In one or more examples, the circular corrugations are described as, or as forming, bellows.
Referring generally to
Having at least one weakened region 134 between adjacent ones of receptacles 104, individual or subsets of receptacles 104 may be separated from a remainder of ignition-suppressing device 100 during installation thereof, such as following installation over a linear row of fasteners 106 and/or when the spacing between receptacles 104 is not aligned with the spacing of fasteners 106, over which receptacles 104 are being positioned.
In one or more examples, multiple weakened regions extend laterally across ribbon 102 between adjacent ones of receptacles 104.
By including multiple weakened regions, such as at least one weakened region 134, between adjacent ones of receptacles 104, different lengths of ribbon 102 may be selectively removed during installation of ignition-suppressing device 100 to correspond to various spacings of fasteners 106.
In one or more examples, in addition to or in place of the multiple weakened regions, indicia representing cut lines are provided to facilitate a technician separating adjacent regions of ignition-suppressing device 100 along a weakened region or cutting ignition-suppressing device 100 along the cut lines.
Referring generally to
Perforations 148 facilitate separation of adjacent portions of ignition-suppressing device 100 without the need for a tool, such as scissors or other cutter.
Referring generally to
Score lines facilitate separation of adjacent portions of ignition-suppressing device 100 without the need for a tool, such as scissors or other cutter.
Referring generally to
Concentric rings 136 provide structure to maintain receptacles 104 in a generally circular configuration around fasteners 106 when ignition-suppressing device 100 is installed. Moreover, in one or more examples, concentric rings 136 facilitate receptacles 104 collapsing to a collapsed conformation, such as illustrated in
Referring generally to
By being more rigid than substrate portion 152, concentric rings 136 provide structure to maintain receptacles 104 in a generally circular configuration around fasteners 106 when ignition-suppressing device 100 is installed.
Referring generally to
By having different diameters, concentric rings 136 not only facilitate the collapsing and expanding of receptacles 104, but also enable the tapering of receptacles toward the terminal ends of fasteners 106.
Referring generally to
Referring generally to
Examples of the subject matter, disclosed herein may be described in the context of aircraft manufacturing and service method 1100 as shown in
Each of the processes of illustrative method 1100 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include, without limitation, any number of aircraft manufacturers and major-system subcontractors; a third party may include, without limitation, any number of vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.
As shown in
Apparatus(es) and method(s) shown or described herein may be employed during any one or more of the stages of the manufacturing and service method 1100. For example, components or subassemblies corresponding to component and subassembly manufacturing (block 1108) may be fabricated or manufactured in a manner similar to components or subassemblies produced while aircraft 1102 is in service (block 1114). Also, one or more examples of the apparatus(es), method(s), or combination thereof may be utilized during production stages 1108 and 1110, for example, by substantially expediting assembly of or reducing the cost of aircraft 1102. Similarly, one or more examples of the apparatus or method realizations, or a combination thereof, may be utilized, for example and without limitation, while aircraft 1102 is in service (block 1114) and/or during maintenance and service (block 1116).
Different examples of the apparatus(es) and method(s) disclosed herein include a variety of components, features, and functionalities. It should be understood that the various examples of the apparatus(es) and method(s), disclosed herein, may include any of the components, features, and functionalities of any of the other examples of the apparatus(es) and method(s) disclosed herein in any combination.
Many modifications of examples, set forth herein, will come to mind of one skilled in the art, having the benefit of the teachings, presented in the foregoing descriptions and the associated drawings.
Therefore, it is to be understood that the subject matter, disclosed herein, is not to be limited to the specific examples illustrated and that modifications and other examples are intended to be included within the scope of the appended claims. Moreover, although the foregoing description and the associated drawings describe examples of the subject matter, disclosed herein, in the context of certain illustrative combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative implementations without departing from the scope of the appended claims. Accordingly, parenthetical reference numerals in the appended claims are presented for illustrative purposes only and are not intended to limit the scope of the claimed subject matter to the specific examples provided herein.
The present application is a non-provisional of and claims priority to U.S. Provisional Patent Application No. 63/172,245, filed on Apr. 8, 2021, entitled “IGNITION-SUPPRESSING DEVICES FOR SHIELDING FASTENERS, AIRCRAFT FUEL TANKS HAVING FASTENERS, SHIELDED BY IGNITION SUPPRESSING DEVICES, AND METHODS OF INSTALLING IGNITION-SUPPRESSING DEVICES IN AIRCRAFT FUEL TANKS,” the complete disclosure of which is incorporated by reference.
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