Improved thermal protection means

Abstract

Disclosed is a thermal protection means (1) comprising a thermal insulation blanket (2) and a protective layer (3) for protection against fluids which is connected to a face of the thermal insulation blanket, wherein the thermal protection means comprises first connection elements (4) for connecting the protective layer to the thermal insulation blanket, the first connection elements being integral with the thermal insulation blanket and protruding from the face of said thermal insulation blanket.

Description

DESCRIPTION TITLE: IMPROVED THERMAL PROTECTION DEVICE. TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to the field of thermal protection devices for aircraft structural parts. In particular, the invention relates to a thermal protection device. STATE OF PRIOR ART

[0002] Thermal protection devices are used in hot applications within aircraft, such as the engine environment, to protect all or part of the structures in that environment. Such thermal protection devices are subject to fluid splashes and require preventing the accumulation of these fluids within the device. For example, thermal protection devices used in nacelles generally perform the following main functions.

[0003] They allow the temperature of a structure with low temperature resistance to high and permanent heat fluxes to be limited, the thermal protection device continuously creating a temperature drop between a motor zone radiating at 400-450°C for example and an internal face of the composite structure which must not peak at more than 125°C continuously.

[0004] They allow the structure with low thermal resistance to withstand sufficiently and for a defined duration a fire which starts on the hot side, for example a fire at 1050°C for 15 min, the damage to the composite structure and in particular the matrix must not be completely pyrolyzed, for this in general the temperature reduction generated by the thermal protection device must be in the order of 500 to 700°C.

[0005] Furthermore, thermal protection devices must withstand fluid splashes and not become saturated with flammable liquids in particular. The fluid must run off the thermal protection device. They must also They must withstand oxidizing atmospheres in the temperature range, for example, up to 400-450°C. Furthermore, such thermal protection devices must be as thin (in size) and light as possible for aeronautical applications.

[0006] Currently, to meet these severe conditions, thermal protection systems are generally designed with a thermal insulation layer made of materials with very low thermal conductivity, based on stacks of fabrics or non-woven ceramic or mineral fibers resistant to over 1050°C, sometimes with the layers stitched together. A stainless steel strip is placed against each side of this thermal insulation layer, and crimped or welded seams ensure complete encapsulation of the thermal insulation layer within the strips. Rivets between the two strips and through the thermal insulation layer are distributed across the entire surface to ensure close contact between the strips and the thermal insulation layer, and also to allow for fixing the thermal protection system to the structure.In addition, at least one vent is provided to ensure iso-pressure between the interior of the thermal protection device's mattress volume and the surrounding environment.

[0007] Finally, their integration into the structure is achieved by attaching them to specific points on the structure to be protected. This structure can be made of composite material or lightweight metal / alloy (such as aluminum). Currently, they are attached using screws or rivets through the thermal protection device at designated points, or with metal wires connecting a base on the structure to be protected to a cap, thus enclosing the thermal protection device. Another existing solution involves attaching them to the structure using hook-and-loop fasteners or clips, one of which is fixed to the metal strip facing the composite structure or passes through the thermal protection device.

[0008] However, current thermal protection devices have drawbacks. The metal strips must be relatively thick, and are therefore heavy. The rivets create thermal bridges that must be specifically addressed. The attachment points must be correctly positioned relative to the passages provided in the thermal protection devices at the risk of not being able to install said thermal protection device on the structure. DESCRIPTION OF THE INVENTION

[0009] One aim of the invention is to provide a thermal protection device which partially addresses the aforementioned drawbacks.

[0010] To this end, the invention provides a thermal protection device comprising a thermal insulation mattress and at least one fluid protection layer attached to at least one face of the thermal insulation mattress, wherein the thermal protection device includes first connecting elements of the protection layer with the thermal insulation mattress, the first connecting elements being attached to at least one of the thermal insulation mattress and the fluid protection layer and extending out of at least one face of the thermal insulation mattress and / or a face of the fluid protection layer extending opposite the face of the thermal insulation mattress.

[0011] Advantageously, but optionally, the thermal protection device according to the invention has at least one of the following technical characteristics: - the thermal protection device includes second connecting elements attached to the thermal insulation mattress and extending outwards from another face of the thermal insulation mattress; - the thermal protection device includes another layer of protection against fluids linked to another face of the thermal insulation mattress via the second connecting elements; - the fluid protection layer having another face, at least the other face of the fluid protection layer has means for fluid flow, in particular grooves, ribs and / or corrugations; - all or part of the connecting elements include metallic wires or strands of mineral or ceramic fibers; - all or part of the connecting elements include metallic ribbons; - all or part of the connecting elements are trapped by stitching in the thermal insulation mattress; - all or part of the connecting elements are woven with the thermal insulation mattresses; - all or part of the bonding elements are continuous, originating from materials joined together; - all or part of the connecting elements are independent of each other; - all or part of the connecting elements include a perforated ribbon fixed on a longitudinal edge by fixing wires to the thermal insulating mattress; - the protective layer against fluids envelops a part extending in projection from the thermal insulation layer of the connecting element; - the protective layer against fluids is glued, welded or brazed to the bonding element; - the connecting element includes a welding material; and, - the connecting element passes through a thickness of the protective layer against fluids.

[0012] The invention also provides for an aircraft structure comprising a receiving face, in which the receiving face is at least partially covered with a thermal protection device having at least one of the preceding technical characteristics.

[0013] Advantageously, but optionally, the structure according to the invention has at least the following technical characteristic: the receiving face includes connecting means arranged so as to cooperate with the second fixing elements of the thermal protection device.

[0014] The invention also provides for a method of making a previous thermal protection device having steps of: a) Making a thermal insulating mattress with the connecting elements extending in projection from the face of the thermal insulating mattress along a normal to said face; b) Placement of the fluid protection layer on the face of the thermal insulation mattress, the fluid protection layer enveloping the protruding part of the connecting elements; and, c) Deformation by folding of the thus-enveloped protruding part of the connecting elements against the face of the thermal insulation mattress. BRIEF DESCRIPTION OF THE FIGURES

[0015] Other features and advantages of the invention will become apparent from the following description of an embodiment of the invention. See the attached drawings: [Fig.1] is a cross-sectional view of a thermal protection device according to the invention; [Fig.2] is a three-dimensional view of a first embodiment of the thermal insulating mattress of the thermal protection device of figure 1; [Fig.3] is a partial cross-sectional view of the thermal insulation mattress in Figure 2; [Fig. 4] is a partial cross-sectional view of a second embodiment of a thermal insulating mattress; [Fig.5] is a partial cross-sectional view of an alternative embodiment of the second embodiment of a thermal insulating mattress; [Fig.6] is a three-dimensional view of a third embodiment of a thermal insulating mattress; [Fig.7] is a partial cross-sectional view of the thermal insulation mattress in Figure 6; [Fig.8] is a partial cross-sectional view of an assembly of the thermal protection device according to the invention on a structure; [Fig.9] is a partial cross-sectional view of a step in the realization of the protection device of figure 1; [Fig.10] is a partial cross-sectional view of a step in the realization of the protection device of figure 1, following the step illustrated in figure 9; [Fig. 11] is a partial cross-sectional view of a fourth embodiment of a thermal insulating mattress; [Fig.12] is a partial cross-sectional view of an assembly between the thermal insulation mat of Figure 11 and a fluid protection layer; and, [Fig.13] is a partial cross-sectional view of an alternative embodiment of the assembly between the thermal insulation mat of Figure 11 and a fluid protection layer.

[0016] For clarity, identical or similar elements are identified by identical reference symbols across all figures. DETAILED DESCRIPTION OF A METHOD OF IMPLEMENTATION

[0017] With reference to figure 1, we will describe an embodiment of a thermal protection device 1 according to the invention.

[0018] The thermal protection device 1 according to the invention comprises a thermal insulating mattress known per se. For example, the thermal insulating mattress 2 is made of materials with very low thermal conductivity, based on a stack of fabrics or non-woven ceramic or mineral fibers resistant to temperatures exceeding 1050°C, optionally the stack being sewn between layers. The thermal insulating mattress 2 has two main faces, a face 21 to which a fluid protection layer 3 is attached, and an opposing face 22.

[0019] The thermal protection device 1 according to the invention further comprises a fluid protection layer 3 extending opposite the face 21 of the thermal insulation mat 2. In particular, the fluid protection layer 3 is a strip or foil made from a metallic material such as, for example, aluminum foil or film, or annealed or austenitic stainless steel. The fluid protection layer 3 is of low thickness to allow for deformation while remaining lightweight, for example, a thickness between 0.01 mm and 0.4 mm, preferably between 0.015 mm and 0.15 mm. The fluid protection layer 3 covers all or part of the face 21 of the thermal insulation mat 2.

[0020] On the other hand, the fluid protection layer 3 has two faces, one face which extends opposite face 21 of the thermal insulation mat 2 and another, opposite face, which is intended to receive fluids or fluid sprays. This other face includes, for this purpose, fluid flow means such as channels, ribs, and / or corrugations, facilitating the flow of fluids received by the other face. The fluid flow means are, for example, engraved (laser engraving or otherwise), machined, rolled, etc. The flow means are oriented so as to direct a flow towards a predetermined area of ​​the thermal protection device 1 according to the invention or located outside it at a periphery. Alternatively, both faces include the fluid flow means.

[0021] In order to fix the fluid protection layer 3 to the face 21 of the thermal insulation mattress 2, the thermal protection device 1 according to the invention comprises first connecting elements 4 which extend in projection from the face 21 of the thermal insulation mattress 2. The first connecting elements 4 are integral with the thermal insulation mattress 2.

[0022] With reference to Figure 3, the first connecting elements 4 each comprise a portion 43 that projects from the face 21 of the thermal insulation mat 2. Initially, before the fluid protection layer 3 is installed, the portion 43 extends perpendicularly to the face 21 of the thermal insulation mat 2. Another portion 44, 45, complementary to the portion 43 of each of the first connecting elements 4, secures the first connecting element 4 to the thermal insulation mat 2. The first connecting elements 4 are distributed over a surface area of ​​the face 21 of the thermal insulation mat 2. This distribution is uniform or uneven depending on the application in which the thermal protection device 1 according to the invention is used.

[0023] The first 4 connecting elements can be made in different ways and fixed to the thermal insulation mattress 2 in different ways.

[0024] According to a first embodiment, illustrated in Figure 3, the first connecting elements 4 linked to the thermal insulation mattress 2 comprise portions 43 protruding normal to the face 21 of the thermal insulation mattress 2, and a portion 6a of these first connecting elements 4 is inseparably entangled with the thermal insulation mattress 2 by being caught in at least one part materials forming said thermal insulation mattress 2. Here, the first connecting elements 4 are formed of metal wires or strands of mineral or ceramic fibers. In one embodiment, the first connecting elements 4 are woven or at least interwoven with the thermal insulation mattress 2, when the latter is made of a single fabric. In another embodiment, the first connecting elements 4 are attached to the thermal insulation mattress 2 by being sewn into the thermal insulation mattress 2, which seam joins part or all of the thermal insulation mattress 2 and the first connecting element 4.

[0025] In yet another variant, the first 4 connecting elements are metal ribbons.

[0026] In another variation, the connecting elements are independent of each other at each connection point with the insulating mattress and the barrier flashing. Advantageously, this allows for greater flexibility in the installation of the connecting elements on the mattress. It can also allow for greater freedom in the mattress's deformation, as it is not restricted by the rigidity of the connecting element.

[0027] According to a first aspect illustrated in Figures 2 and 3, for example, all or part of the first connecting elements 4 are continuous, made from materials joined together. These first connecting elements 4 are made from a single wire or strand 6, 6a, 6b. Thus, it is faster to install a set of first connecting elements 4 on a thermal insulation mat 2.

[0028] According to a second aspect which can be combined with the previous one, all or part of the linking elements 4 are independent of each other forming separate elements made up of parts 43 and 44.

[0029] With reference to Figures 4 and 5, a second embodiment and a variant are illustrated. Here, the thermal protection device 1 according to the invention comprises second connecting elements 5 that project from the other face 22 of the thermal insulation mat 2. The second connecting elements 5 are integral with the thermal insulation mat 2, as are the first connecting elements 4. Each of the second connecting elements 4 comprises a portion 53 which extends projecting from the other face 22 of the thermal insulation mattress 2. Initially, before the possible application of a fluid protection layer 3, the portion 53 extends along a normal to the other face 22 of the thermal insulation mattress 2. Another portion 44, complementary to portion 53 of each of the second connecting elements 4, allows the second connecting element 4 to be joined to the thermal insulation mattress 2. In Figure 4, the first connecting elements 4 and the second connecting elements 5 are continuous, made from one material to the other, in a single wire or strand 6. Alternatively, in Figure 5, the first connecting elements 4 are continuous, made from one material to the other, in a single wire or strand 6a, and the second connecting elements 5 are continuous, made from one material to the other, in another single wire or strand 6b. In general, the second 5th bonding elements are similar to the first 4th bonding elements.

[0030] In a first use of the second embodiment, the thermal protection device 1 according to the invention is provided on this other face with another layer of protection against fluids 3 linked on the other face 22 of the thermal insulation mattress 2 via the second connecting elements 5, in the same way as the layer of protection against fluids 3 linked on the face 21 to the thermal insulation mattress 2. Thus, the thermal insulation mattress 2 is completely encapsulated in the layers of protection against fluids 3, further protecting it from the risks of fluid absorption.

[0031] In a second use of the second embodiment illustrated in figure 8, the second connecting elements 5 with which the other face 22 is provided cooperate with connecting means 1 arranged on a face 12 of a structure to be protected and linked to it, the second connecting elements 5 and the connecting means 11 intertwining to achieve the assembly of the thermal protection device 1 according to the invention to the structure 10, in the manner of a Velcro or a hook and loop type connection.

[0032] With reference to Figures 6 and 7, a third embodiment is illustrated. Here, the first (or second) connecting elements 40 comprise two parts, one of which is a perforated strip 41 placed on a longitudinal edge on face 21 of the thermal insulating mattress 2, and the other is a fixing wire 42 linking the thermal insulating mattress 2 with said openwork tape 40.

[0033] With reference to Figures 3, 9, and 10, we will briefly describe a method for implementing the thermal protection device 1 according to the invention. In a first step (Figure 3), a thermal insulation mat 2 is made with the first 4 and / or second 5 connecting elements extending outward from face 21 and / or the other face 22 of the thermal insulation mat 2 along a normal to said face. Then, in a second step (Figure 9), the fluid protection layer 3 is placed on face 21 and / or the other face 22 of the thermal insulation mat 2, the fluid protection layer 3 enveloping the protruding portion 43, 53 of the connecting elements 4, 5. This is possible because the fluid protection layer 3 is thin and has sufficient deformability to be "crumpled" around the protruding portion 43, 53.In a third step (figure 10), the protruding part 43,53 thus wrapped by the first 4 and / or second 5 connecting elements is deformed by folding against the face 21,22 of the thermal insulating mattress 2. This deformation is carried out by crushing for example.

[0034] Now, with reference to Figures 11, 12, and 13, we will describe a fourth embodiment of the invention. The thermal insulation mat 2 comprises first connecting elements 4 having, as previously described, a projecting portion 43 and another complementary portion 45 for fixing to the thermal insulation mat 2 in order to secure the first connecting elements 4 to the thermal insulation mat 2. At a free end of the projecting portion 43, each of the first connecting elements 4 has a portion of welding material 43, which is, for example, in the form of a ball. Alternatively, the first connecting elements 4 are metallic and of a nature compatible with welding or brazing to a material of the fluid protection layer 3.Thus, when assembling the thermal insulation mattress 2 with a fluid protection layer 3, the first connecting elements 4 are welded or brazed to the fluid protection layer 3. Alternatively, the first connecting elements 4 are bonded to the fluid protection layer 3, for example using cement.

[0035] In a first method, the fluid protection layer 3 is placed against the face 21 of the thermal insulation mattress 2, sandwiching the protruding part 43, the welding or brazing taking place "blindly" with an internal face of the fluid protection layer 3 opposite the face 21 of the thermal insulation mattress 2.

[0036] In a second method, the protruding part 43 of the first connecting elements passes through holes made through a thickness of the fluid protection layer 3 and is welded or brazed from the outside while sealing the passage (thanks to the welding / brazing).

[0037] The thermal protection device 1 according to the invention has been described with connecting elements attached to the thermal insulation layer 2. In an alternative embodiment, the connecting elements, in particular the first connecting elements 4, are attached to the fluid protection layer 3. For example, the first connecting elements 4 attached to the fluid protection layer 3 are connected, hooked, etc., to the thermal insulation layer 2. In yet another alternative embodiment, the connecting elements, in particular the first connecting elements 4, are attached partly to the fluid protection layer 3 and partly to the thermal insulation layer 2. In all cases, the connecting elements extend projecting from the face of the thermal insulation layer 2 opposite the fluid protection layer 3 and / or from the other face of the fluid protection layer 3.

[0038] It follows from the above that the use of a thermal protection device 1 according to the invention previously described makes it possible to thin and lighten the thermal protections for aircraft subjected to high temperatures, which must resist fire and must withstand liquid splashes without absorbing them, while ensuring uniform and optimal protection over the whole of a surface of the thermal protection device 1 according to the invention.

[0039] Naturally, the invention described above is by way of example. It is understood that a person skilled in the art is capable of carrying out different embodiments of the invention without departing from its scope.

[0040] It is emphasized that all features, as they are apparent to a person skilled in the art from the present description, drawings and attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances render such combinations impossible or meaningless.

Claims

DEMANDS 1. Thermal protection device (1) comprising a thermal insulation mat (2) and at least one fluid protection layer (3) bonded to at least one face (21) of the thermal insulation mat, wherein the thermal protection device includes first connecting elements (4;40) of the protection layer with the thermal insulation mat, the first connecting elements being integral with at least one of the thermal insulation mat and the fluid protection layer and extending projecting from at least one face of the thermal insulation mat and / or from a face of the fluid protection layer extending opposite the face of the thermal insulation mat.

2. Thermal protection device according to claim 1, wherein the thermal protection device comprises second connecting elements (5) integral with the thermal insulation mattress and extending projecting from another face (22) of the thermal insulation mattress.

3. Thermal protection device according to claim 2, wherein the thermal protection device comprises another fluid protection layer (3) linked to another face of the thermal insulation mat via the second connecting elements.

4. Thermal protection device according to any one of claims 1 to 3, wherein, the fluid protection layer having another face, at least the other face of the fluid protection layer has fluid flow means, in particular grooves, ribs and / or corrugations.

5. Thermal protection device according to any one of claims 1 to 4, wherein all or part of the connecting elements (4,5) comprise metal wires or strands of mineral or ceramic fibers.

6. Thermal protection device according to any one of claims 1 to 4, wherein all or part of the connecting elements comprise metallic ribbons.

7. Thermal protection device according to any one of claims 1 to 6, wherein all or part of the connecting elements are trapped by stitching in the thermal insulation mattress.

8. Thermal protection device according to any one of claims 1 to 7, wherein all or part of the connecting elements are woven with the thermal insulating mattresses.

9. Thermal protection device according to any one of claims 1 to 8, wherein all or part of the connecting elements (40) comprise a perforated strip (41) fixed on a longitudinal edge by fixing wires (42) with the thermal insulating mat.

10. Thermal protection device according to any one of claims 1 to 9, wherein the fluid protection layer is bonded, welded or brazed with the bonding element.

11. Thermal protection device according to claim 10, wherein the connecting element comprises a welding material (46).

12. Thermal protection device according to claim 10, wherein the connecting element passes through a thickness of the fluid protection layer.

13. Structure (10) of an aircraft comprising a receiving face (12), in which the receiving face is at least partially covered with a thermal protection device according to any one of claims 1 to 12.

14. Structure according to claim 13, wherein, the thermal protection device being according to claim 2, the receiving face comprises connecting means (11) arranged so as to cooperate with the second fixing elements of the thermal protection device.

5. A method for making a thermal protection device according to any one of claims 1 to 12, wherein the method comprises the steps of: a) Making a thermal insulating mattress with the connecting elements extending in projection from the face of the thermal insulating mattress at a normal to said face; b) Placing the fluid protection layer on the face of the thermal insulating mattress, the fluid protection layer enveloping a projecting part of the connecting elements; and, c) Deforming by folding the projecting part thus enveloped of the connecting elements against the face of the thermal insulating mattress.

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