This invention relates to a burst-out disc, a compartmental barrier comprising at least one such burst-out disc and a method for providing isolation between two internal volumes within an aircraft.

It is known to provide isolation between neighbouring volumes within an aircraft by using a barrier. For example, within an aircraft fuselage, the crew / passenger compartment may be environmentally isolated from the cargo compartment so as to provide smoke or flame isolation, thereby reducing smoke or flame dispersion within the fuselage of the aircraft. Said barriers generally remain fixed in place should a decompression event occur on one side of the barrier. To this end, decompression panels may be provided in the barrier to protect the aircraft structure from damage.

Various "venting" systems for aircraft are known from: US-A1 -20120234973, DE-A1 -10201 1015708, US-A-4899960, US-A-5871 178, US-B2-8240604 and US-A1 - 2013/0340954. These generally show the use of decompression panels, caused to open at certain pressure differentials.

However, for some applications, e.g. the transportation of live animals, the transportation of medical supplies, etc., there is no requirement for the barrier to provide a smoke seal. In fact, the barrier must permit an amount of smoke to pass through in order to activate the aircraft smoke detectors. There may also be an additional requirement that the barrier must minimise heat dissipation through the barrier to provide an internal volume which is maintained at a given temperature, e.g. at a temperature which does not harm a live animal, or a temperature that does not spoil medical supplies.

It is an aim of the present invention to provide a compartmental barrier to divide an aircraft interior into two volumes, wherein the barrier minimises heat dissipation through the barrier while still allowing the transmission of enough smoke to pass through in order to activate the aircraft smoke detectors, wherein the barrier is capable of withstanding a decompression event.

This aim is achieved by providing an isolation barrier with at least one burst-out disc configured to fail at a predetermined pressure differential. The burst-out discs of the present invention exhibit a precise performance during a rapid decompression event due to being calibrated, as explained below, to be activated at specific threshold pressures.

In a preferred embodiment, a flexible barrier is provided that separates an internal volume of the aircraft, the barrier including one or more burst-out discs configured to fail at predetermined pressure differential values, thereby permitting a predetermined flow of air through the barrier during a decompression event. The panels provide an environmental seal and also accommodate decompression events without being affected by dirt, debris or the like. The panels are designed to vent at pressures above that of 'normal' operational pressure variations. They are of a non-fragmentation design and thus no other isolation device is required to retain ruptured components.

In accordance with a first aspect of the present invention there is provided a compartmental barrier comprising:

a cover having an aperture therein, the cover comprising a pocket around the edge of the aperture; and

a burst-out disc substantially covering the aperture, and located within the pocket.

The pocket could comprise a first pocket part and a second pocket part, wherein a first skin of the cover is folded back on itself to form the first pocket part, and a second skin of the cover is folded back on itself to form the second pocket part. The first pocket part could contains a first ring of material and a second ring of material. The second pocket part could contain a third ring of material and a fourth ring of material. The first skin and second skin of the cover could have a ply orientation of 0°, and a ring in each pocket part could be formed of a material with 30° ply orientation. A ring in each pocket part could be formed of a material with 60° ply orientation. The rings of each pocket part could be sandwiched between respective layers of double sided tape.

The burst-out disc could comprise a decompression disc. The burst-out disc could comprise an insulation disc. The decompression disc and the insulation disc could be contained within a burst-out disc first skin and a burst-out disc second skin that are stitched together at their peripheries. The burst-out disc first skin could have a ply orientation of 0°, and the burst-out disc second skin could have a ply orientation of 45°. The decompression disc and the insulation disc could be sandwiched between three layers of double sided tape.

The burst-out disc could be attached to the cover by a tether. The cover could be formed of a flexible textile material.

In accordance with a third aspect of the present invention there is provided a method for providing isolation between two internal volumes within an aircraft, the method comprising the step of:

providing a compartmental barrier as described above within the aircraft; and

securing the cover of the compartmental barrier to the interior surfaces of the aircraft between the two internal volumes.

Detailed description

The invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 schematically shows a front view of a barrier in accordance with an embodiment of the present invention; Fig. 2 schematically shows a cross-sectional view taken across the line A-A shown in Fig. 1 ;

Fig. 3 schematically shows a cross-sectional view taken across the line B-B shown in Fig. 1 ;

Fig. 4 schematically shows a cross-sectional view taken across the line C-C shown in Fig. 1 ;

Fig. 5 schematically shows a cross-sectional view taken across the line D-D shown in Fig. 4;

Fig. 6 schematically shows a partial view of a textile having a ply orientation of 0° to a reference direction V; and

Fig. 7 schematically shows a partial view of a textile having a ply orientation of 45° to a reference direction V.

Fig. 1 shows a front view of a barrier 10 in accordance with an embodiment of the present invention. The barrier 10 comprises a plurality of burst-out discs (three of which are indicated at 12) which will be described in detail below. The barrier 10 is used to sub-divide an aircraft main body into cargo compartments, thus dividing up what was previously one compartment. The barrier 10 takes the form of a flexible textile barrier, which is tightly secured and sealed with the interior of the compartment, for example using various fastener types, to create a wall section.

The barrier 10 comprises a plurality of intersecting horizontal and vertical straps which are stitched together at their intersections to form a net body 14, as well as a thermal cover 16. The net body 14 provides a structural function, and is attached to the cover 16 by a single row of stitching indicated at 18. Some of the vertical straps can be tightened using tensioners (two of which are indicated at 20). To provide additional anchorage, the net body 14 is also passed through loops 22 stitched to the cover 16.

Fig. 2 schematically shows a cross-sectional view taken across the line A-A shown in Fig. 1. Like reference numerals have been retained to indicate like components. To attach the net body 14 to the cover, a strap of the net body 14 is layered over the cover 16 and a single row of stitching 18 is passed through both the strap and the cover as shown. In the embodiment shown, the distance from the edge of the strap, indicated by T, is approximately 10mm.

Fig. 3 schematically shows a cross-sectional view taken across the line B-B shown in Fig. 1. Again, like reference numerals have been retained to indicate like components.

To provide additional anchorage, during assembly a free end of a strap of the net body 14 is passed under a loop 22 which is stitched to the cover 16 by stitches 24. The free end is passed through a ring (see Fig. 1 ) which is fixed to a side of the barrier 10, returned back over the loop 22 and inserted into a tensioner 20 (see Fig. 1 ).

Fig. 4 schematically shows a cross-sectional view taken across the line C-C shown in Fig. 1 . Again, like reference numerals have been retained to indicate like components.

The burst-out disc 12 comprises a decompression disc 62 and an insulation disc 64, which sits within a pocket formed in the thermal cover 16, and covering a circular aperture in the thermal cover 16. The decompression disc 62 is formed of polycarbonate. Other suitable materials for the decompression disc 62 include steel, aluminium and carbon fibre. The two discs 62, 64 are sandwiched between three layers of double sided tape 66. The assembly of tape and discs is contained within a first skin 68 and a second skin 70. The second skin 70 is attached to the first skin 68 by an outer row of stitching 72 and an inner row of stitching 74. The first skin 68 has a ply orientation of 0° and the second skin 70 has a ply orientation of 45° (these terms will be explained below with reference to Figs. 6 and 7).

The thermal cover 16 forms a pocket to hold the burst-out disc 12. A first skin 76 of the thermal cover 16 folds back upon itself as shown to form a first part of the pocket and a second skin 78 of the thermal cover 16 folds back upon itself as shown to form a second part of the pocket. The thermal cover 16 also comprises a layer of insulation 92.

The first part of the pocket contains a first ring of material 80 and a second ring of material 82. The second part of the pocket contains a third ring of material 84 and a fourth ring of material 86.

The first skin 76 and the second skin 78 of the thermal cover 16 each have a ply orientation of 0°. The first and third rings 80, 84 each have a ply orientation of 30°. The second and fourth rings 82, 86 each have a ply orientation of 60° (these terms will be explained below with reference to Figs. 6 and 7). The first and second rings 80, 82 are sandwiched between layers of double sided tape 88. The third and fourth rings 84, 86 are sandwiched between layers of double sided tape 90.

The first, second, third and fourth rings 80, 82, 84, 86 provide a stiffening function around the rim of the aperture in the thermal cover 16. The extent of the stiffening can be configured by varying the diameter of the aperture, the depth of the pocket, the number of stiffening rings, the stiffness of the burst-out disc 12, the diameter and eccentricity of the decompression disc 62. Configuring the extent of the stiffening in turn allows the burst panel to be tuned to activate at a predetermined pressure, or within a predetermined pressure range.

As exemplary dimensions, in the example shown in Fig. 4 the diameter of the decompression disc 62 and the insulation disc 64 (indicated by double-ended arrow X) is 180mm, the diameter of the aperture (indicated by double-ended arrow Y) is 210mm, and the depth of each of the pockets (indicated by double-ended arrows Z) is 21 mm.

Fig. 5 schematically shows a cross-sectional view taken across the line D-D shown in Fig. 4. Here, it can be seen that the skin 76 of the thermal cover 16 comprises a plurality of tabs 94. These fold over the double sided tape layers 88 and completely conceal them. This prevents the burst disc-out 12 from sticking to the double sided tape layers 88. The dashed lines 96 indicate two lines of stitching which secure the tabs 94 and the stiffening rings 80, 82 in place.

Fig. 6 schematically shows a partial view of a first textile 100 having a ply orientation of 0° to a reference direction V. The first textile 100 comprises a plurality of first fibres 102 all substantially aligned in the same first direction to one another and interwoven with a plurality of second fibres 104. The plurality of second fibres 104 are all substantially aligned in the same second direction, which is perpendicular to the first direction. In the art, the plurality of first fibres 102 is sometimes referred to as the warp, and the plurality of second fibres 102 is sometimes referred to as the weft.

In Fig. 6, a reference direction V is indicated. The first direction, with which the plurality of first fibres 102 are aligned, runs in the same direction as the reference direction V. The first textile 100 is therefore said to have a ply orientation of 0°, as the angle between the first direction and the reference direction is 0°.

Fig. 7 schematically shows a partial view of a second textile 200 having a ply orientation of 45° to a reference direction V. As in Fig. 6, the second textile 200 comprises a plurality of first fibres 202 all substantially aligned in the same first direction to one another and interwoven with a plurality of second fibres 204. The plurality of second fibres 204 are all substantially aligned in the same second direction, which is perpendicular to the first direction.

A reference direction V is indicated, which is the same reference direction as in Fig. 6. The first direction, with which the plurality of first fibres 202 are aligned, runs in a direction which is at 45° to the reference direction V. The second textile 200 is therefore said to have a ply orientation of 45°, as the angle between the first direction and the reference direction (indicated at W) is 45°. The second textile 200 may also be said to have a ply orientation of 45° with respect to the first textile 100.

In Figs. 6 and 7, the reference direction V has been given as a vertical direction. However, it should be appreciated that any reference direction may be used in practice, provided it is used consistently from material to material. For simplicity, in this document all ply orientations are given with respect to a vertical direction in all cases.

Providing materials at relative non-0790 180 270° ply orientations to one another before stitching or otherwise sealing the materials together (e.g. by coating) gives a resulting material with greater strength compared to where ply orientations are aligned or perpendicular to one another. The exemplary ply orientations referred to with respect to Fig. 4 above have been found through testing to produce pockets and burst-out discs of particular strength and durability suitable for use in decompression barriers.

The burst-out disc described with respect to the barrier above is bidirectional. This means that it will rupture at the predetermined pressure differential value whichever side is exposed to the greater atmospheric pressure volume. The burst-out disc may be attached to the thermal cover by a flexible tether. The tether will not interfere with the operation of the burst-out disc, but will prevent it from becoming loose in the aircraft interior following activation.

The exemplary dimensions given above with respect to Fig. 4 produce a burst out disc configured to activate in a range of 0.6 pounds per square inch (4137 Pascal) to 1.0 pounds per square inch (6895 Pascal). Each burst-out disc provides a geometric free area of 0.035 square meters. The barrier shown in Fig. 1 has a thermal resistance of approximately 0.16 m ² K/W.

The above-described embodiments are exemplary only, and other possibilities and alternatives within the scope of the invention will be apparent to those skilled in the art. For example, the insulation layer can be omitted from the thermal cover if the application does not require a high degree of thermal resistance, or if the thermal barrier provides enough thermal insulation on its own without the inclusion of the insulation layer. While the stiffening rings are textile in the embodiment described above, they could equally be formed of polycarbonate or carbon fibre. Additionally, double sided tape is only one example of means to secure the stiffening rings in place and hold them together. Any suitable retaining means could be used in practice. A barrier according to the invention may be used as part of an aircraft passenger to freighter conversion.