Flame resistant shield
A flame resistant shield includes two opposing walls between which are positioned at least: a first insulating layer, the first layer being capable of distributing heat in the plane formed by the first layer and being insulating across its thickness, a second insulating layer, one of the opposing walls which covers the first layer being produced from a refractory antioxidant material or having at least the surface intended to be exposed to flames covered with a material preventing this surface from being oxidized, the other wall being a support.
1. A flame resistant shield comprising:
two opposing walls between which there are placed at least,
a first insulating layer, said first insulating layer being able to dissipate heat in the plane formed by said first insulating layer while being insulating in its thickness;
a second insulating layer,
wherein one of said opposing walls which covers said first insulating layer is made of an antioxidant refractory material or at least a face of the one of the said opposing walls which is designed to be exposed to flames is covered with a material preventing oxidation of this face of the one of the said opposing walls,
the other wall being a support; and
further comprising attachments disposed at least partially between the two opposing walls for securing the two opposing walls and the first and second insulating layers of the shield together, the attachments having a configuration that bidirectionally fixes a gap between the two opposing walls that effects definition and control, between the two opposing walls, of a density of each insulating layer in its entirety, said attachments each comprise a hollow insert of cylindrical shape interposed directly between the two opposing walls, one bolt, washers, and one nut.
2. The shield as claimed in claim 1 , wherein said first and second insulating layers contain no resin.
3. The shield as claimed in claim 1 , wherein said first insulating layer is made of an orthotropic conductive material.
4. The shield as claimed in claim 3 , wherein a radial thermal conductivity of said first insulating layer is greater than 100 W·m −1 ·K −1 at 20° C. whereas its axial thermal conductivity is less than 10 W·m −1 ·K −1 at 20° C.
5. The shield as claimed in claim 1 , wherein said second insulating layer has a thermal conductivity of less than 1 W·m −1 ·K −1 at 20° C.
6. The shield as claimed in claim 5 , wherein said second insulating layer has an area density of 15.7 kg/m 2 .
7. The shield as claimed in claim 1 , wherein, the support being made of a titanium alloy, has a thickness greater than or equal to 0.6 mm.
8. An engine nacelle equipped with a flame resistant shield as claimed in claim 1 .