Arc suppression around fasteners
AssigneeThe Boeing Company
InventorJames H. Covey
Life of this patent
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Abstract
A volume of gas is enclosed by a cap around a fastener that is through a composite structure on an aircraft. The gas provides spark suppression for arcing that may occur between the composite structure and the metal fastener during a lightning strike. The volume of gas is sufficiently large to absorb the energy of small, very hot particles of graphite, epoxy, etc., that may be present resulting from arcing. High-pressure gas regions between the fastener and composite member vent to the larger volume of gas and are absorbed. This provides effective spark suppression for particular areas in an aircraft, such as a fuel tank, etc.
Claims13
A spark containment apparatus comprising:
- a first member of composite material which includes a material that changes phase from solid to gas at temperatures below 1000.degree. F.;
- a second member of composite material which includes a material that changes phase from solid to gas at temperatures below 1000.degree. F.;
- a fastener extending through said first member and into said second member for connecting said first and second members together, said fastener being electrically conductive;
- and
- an electrically insulating enclosure attached to said first member in an airtight, sealed relationship and spaced from said fastener to provide a gas-filled void between said fastener and said enclosure.
In an aircraft structure having a composite member attached to a second member with a metal fastener, a portion of said fastener extending through said composite member and projecting from a surface of said composite member, the improvement comprising:
- attaching an electrically insulating enclosure to said surface with an airtight seal to enclose a volume of gas surrounding said portion of said fastener to suppress electrical arcing between said composite member and said fastener, and said composite member including a material which changes phase from solid to gas at temperatures below those possibly present on an aircraft structure during a lightning strike.
Dependencies are inferred from the claim text.