Fire containment apparatuses for aircraft duct assemblies

Patent metadata

Field	Value
Publication number	US-2016159489-A1
Application number	US-201414563500-A
Country	US
Kind code	A1
Filing date	Dec 8, 2014
Priority date	Dec 8, 2014
Publication date	Jun 9, 2016
Grant date	—

Abstract

An intake duct assembly for an auxiliary power unit system is provided. A first inlet adapter includes at least one hole through the duct wall. A fire containment apparatus forms a first passage to direct intake air between exterior wall of the aircraft and the enclosure. An inner duct mounted on the first inlet adapter at a first position downstream of the at least one hole and mounted on the second inlet adapter. An outer sheath is mounted on the first inlet adapter at a second position upstream of the at least one hole and mounted on the second inlet adapter. The outer sheath circumscribes the inner duct to form at least a portion of a barrier annulus between the inner duct and outer sheath in fluid communication with the first passage via the at least one hole in the first inlet adapter.

First claim

What is claimed is:

1 . An intake duct assembly for directing intake air between an enclosure of an auxiliary power unit and an exterior wall of an aircraft, the interior duct assembly comprising:
a first inlet adapter configured to be mounted on a first opening through the enclosure, the first inlet adapter including a duct wall defining at least one hole through the duct wall; a second inlet adapter configured to be mounted on a second opening through the exterior wall; and a fire containment apparatus extending between the first inlet adapter and the second inlet adapter to form a first passage to direct intake air in a downstream direction through the second opening in the exterior wall of the aircraft, through the second inlet adapter, through the fire containment apparatus, through the first intake adapter, and into the enclosure through the first opening, the fire containment apparatus comprising:
an inner duct mounted on the first inlet adapter at a first position downstream of the at least one hole and mounted on the second inlet adapter; and
an outer sheath mounted on the first inlet adapter at a second position upstream of the at least one hole and mounted on the second inlet adapter, the outer sheath circumscribing the inner duct to form at least a portion of a barrier annulus between the inner duct and outer sheath in fluid communication with the first passage via the at least one hole in the first inlet adapter.

2 . The intake duct assembly of claim 1 , wherein the fire containment apparatus is configured to, during a fire event, vent combustion products within the barrier annulus through the at least one hole into the main passage.

3 . The intake duct assembly of claim 1 , wherein the inner duct and the outer sheath are flexible.

4 . The intake duct assembly of claim 1 , wherein the inner duct and the outer sheath comprise fiber reinforced silicone rubber.

5 . The intake duct assembly of claim 1 , wherein the barrier annulus has a first closed end at the first inlet adapter and a second closed end at the second inlet adapter.

6 . The intake duct assembly of claim 5 , further comprising an isolation shield mounting the outer sheath on the first inlet adapter, the isolation shield including a first bracket secured to the first inlet adapter and a collar member at least partially supported by the first bracket, the collar member defining a mounting surface for the outer sheath.

7 . The intake duct assembly of claim 6 ,
wherein collar member includes a first flange defining the mounting surface and a radially extending second flange, and wherein the isolation shield further includes a second bracket secured to the first inlet adapter, wherein the first bracket has a radially extending first leg and the second bracket has a radially extending second leg, the first and second legs defining an axial space for receiving the second flange of the collar member.

8 . The intake duct assembly of claim 7 , wherein the isolation shield further includes a first insulation member in between the first leg and the second flange in the axial space and a second insulation member in between the second leg and the second flange in the axial space.

9 . The intake duct assembly of claim 8 , wherein the first and second legs have lengths such that the collar member is separated from the first inlet adapter.

10 . The intake duct assembly of claim 9 , wherein the first leg has a circumferential edge with one or more protrusions that support the collar member.

11 . The intake duct assembly of claim 5 , wherein the first closed end of the barrier annulus is formed by a first seal between the first inlet adapter and the outer sheath.

12 . The intake duct assembly of claim 11 , wherein the outer sheath includes a collar member that forms the first seal with the first inlet adapter.

13 . The intake duct assembly of claim 12 , wherein the collar member is formed by an insulating material.

14 . The intake duct assembly of claim 13 , wherein the collar member is integral with the outer sheath.

15 . An auxiliary power unit system for an aircraft, comprising:
an enclosure defining a first intake opening; an auxiliary power unit arranged within the enclosure; an intake duct assembly extending between the first intake opening in the enclosure to a second intake opening on an external wall of the aircraft, the intake duct assembly comprising
a first inlet adapter mounted on the first intake opening, the first inlet adapter including a duct wall defining at least one hole through the duct wall;
a second inlet adapter mounted on the second intake opening through the exterior wall; and
a fire containment apparatus extending between the first inlet adapter and the second inlet adapter to form a first passage to direct intake air in a downstream direction through the second opening, through the second inlet adapter, through the fire containment apparatus, through the first intake adapter, and into the enclosure through the first opening, the fire containment apparatus comprising:
an inner duct mounted on the first inlet adapter at a first position downstream of the at least one hole and mounted on the second inlet adapter; and
an outer sheath mounted on the first inlet adapter at a second position upstream of the at least one hole and mounted on the second inlet adapter, the outer sheath circumscribing the inner duct to form at least a portion of a barrier annulus between the inner duct and outer sheath in fluid communication with the first passage via the at least one r hole in the first inlet adapter.

16 . The auxiliary power unit system of claim 15 , wherein the fire containment apparatus is configured to, during a fire event, vent combustion products within the barrier annulus through the at least one hole into the main passage.

17 . The auxiliary power unit system of claim 15 , wherein the inner duct and the outer sheath are flexible.

18 . The auxiliary power unit system of claim 15 , further comprising an isolation shield mounting the outer sheath on the first inlet adapter, the isolation shield comprising a first bracket secured to the first inlet adapter and comprising a radially extending first leg;
a second bracket secured to the first inlet adapter and comprising a radially extending second leg, the first and second legs defining an axial space; a collar member with a first flange defining a mounting surface for the outer sheath and a second flange extending into the axial space between the first bracket and the second bracket; a first insulation member positioned within the axial space between the first leg of the first bracket and the second flange of the collar member; and a second insulation member positioned within the axial space between the second leg of the second bracket and the second flange of the collar member.

19 . The auxiliary power unit system of claim 18 , wherein the first leg has a circumferential edge with one or more protrusions that support the collar member.

20 . The auxiliary power unit system of claim 15 , wherein the outer sheath includes a collar member that forms the first seal with the first inlet adapter, the collar member being formed by an insulating material and integral with the outer sheath.

Assignees

• Honeywell Int Inc

Inventors

• Wilcox David Eugene
• Kolberg Thomas
• Hammer Mike

Classifications

• B64D2033/0213

  specially adapted for auxiliary power units (APU's) · CPC title

• B64D33/02 Primary

  of combustion air intakes · CPC title

• F02C7/25

  Fire protection or prevention (in general A62) · CPC title

• B64D41/00 Primary

  Power installations for auxiliary purposes · CPC title