Anti-icing mat, in particular for aircraft component, and method for mounting anti-icing mat

Abstract

The invention relates to an anti-icing mat (1) for a component (BA), in particular for an aircraft component (BA), comprising: a multilayer structure having at least one heating layer (3) capable of generating a heat flux; a contact layer (2) forming at least one thermal barrier between the heating layer (3) and the component (BA); and at least one intermediate layer (4) and / or reinforcing layer (5) and / or outer layer (6), which is thermally conductive and is arranged between the heating layer (3) and the external environment.

Description

Technical Field

[0001] The present invention relates to the anti-icing protection of aircraft components. More specifically, the present invention provides an anti-icing mat for protecting aircraft components from icing. Background Art

[0002] Especially during flight, the accumulation of ice on an aircraft can change the aerodynamic characteristics of the aircraft and impair its performance.

[0003] Furthermore, if ice blocks formed or accumulated on elements of the aircraft fuselage or on engine air intakes break off, these ice blocks may strike parts of the aircraft and damage it.

[0004] Icing can cause at least partial blockage of the air intake, which may also result in power loss and even engine shutdown.

[0005] This is why aircraft are generally equipped with anti-icing devices, also known as de-icers, which are installed, for example, on the leading edges of wings, rudders, radomes or engine air intakes.

[0006] Furthermore, on propeller-driven aircraft, the leading edges of the blades or cones are generally equipped with anti-icing devices.

[0007] It is also known that such anti-icing devices have the function of de-icing or preventing icing.

[0008] There are various techniques for anti-icing devices, such as pneumatic devices with mechanical action, hot air circulation de-icers, etc.

[0009] The present invention more specifically relates to anti-icing devices having anti-icing mats, especially thermoelectric mats.

[0010] Such an anti-icing mat is a heating mat attached to the surface of the component to be anti-iced. Such an anti-icing mat de-ices or prevents icing by the Joule effect, by circulating an electric current in a layer containing at least one heating resistor. Such an anti-icing mat can be operated cyclically or controlled according to an operating mode that ensures permanent heating.

[0011] In particular, the following structure is known: in this structure, the layer containing at least one heating resistor is usually covered by an electrically insulating layer that remains flexible at low temperatures (i.e., at temperatures at which ice may form on the surface to be de-iced), and that has good tolerance to the maximum temperature of the heating resistor. For example, elastomers or thermoplastics, such as polyimide or rubber mixtures, are selected.

[0012] The materials used for such electrical insulation so far are not thermal conductors. Summary of the Invention

[0013] An object of the present invention is to propose a solution that enables better dissipation of the heat flux towards the surface to be de-iced while ensuring good electrical insulation.

[0014] Another object of the present invention is to propose a solution that can save space and reduce the thickness of the anti-icing pad used to protect aircraft components against icing.

[0015] To this end, the present invention proposes an anti-icing pad for a component, in particular for an aircraft component, said pad comprising a multi-layer structure having at least one heating layer, at least one heating layer being capable of generating a heat flux,

[0016] characterized in that the anti-icing pad comprises at least:

[0017] - a contact layer that forms at least one thermal barrier between the heating layer and the component, and

[0018] - at least one intermediate layer and / or reinforcement layer and / or outer layer, at least one intermediate layer and / or reinforcement layer and / or outer layer being thermally conductive and arranged between the heating layer and the external environment.

[0019] Furthermore, according to advantageous and non-limiting features adopted individually or in any combination, :

[0020] - the intermediate layer has electrical insulation and thermal conductivity properties;

[0021] - the reinforcement layer is inserted between the intermediate layer and the outer layer;

[0022] - the reinforcement layer comprises a network of woven, non-woven and / or mesh fibers or threads;

[0023] - the reinforcement layer is conductive and grounded;

[0024] - the outer layer is inserted between the reinforcement layer and the external environment;

[0025] - the outer layer is coated with a coating layer;

[0026] - the thickness of the heating layer, contact layer, intermediate layer (4), reinforcement layer or outer layer is less than 1.5 mm, in particular less than 1 mm, in particular less than 0.7 mm;

[0027] - the thickness of the heating layer, contact layer, intermediate layer, reinforcement layer or outer layer is greater than 0.2 mm, in particular greater than 0.3 mm, in particular approximately 0.4 mm.

[0028] The present invention also relates to an assembly comprising at least one component having an outer surface, in particular an aircraft component, characterized in that the outer surface is covered with an anti-icing pad of the type proposed.

[0029] The present invention also provides a method for mounting the proposed anti-icing pad on the outer surface of a component, in particular an aircraft component, wherein the contact layer is glued or co-vulcanized to the component. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] After reading the following description of the preferred embodiments, other features and advantages of the present invention will become apparent. The description will be given with reference to the accompanying drawings, which include:

[0031] - Figure 1 schematically shows an assembly including a component and an anti-icing pad according to an embodiment of the present invention;

[0032] - Figure 2 schematically shows the multi-layer structure of the anti-icing pad according to an embodiment of the present invention;

[0033] - Figure 3 schematically shows a composite material of an electrically insulating and heat-conducting layer;

[0034] - Figure 4 shows a measuring device for determining the electrical resistance of the anti-icing pad according to the present invention; and

[0035] - Figure 5 shows a measuring device for determining the electrical resistance and leakage current of the anti-icing pad according to the present invention. DETAILED DESCRIPTION

[0036] In the description of the present invention to be given, the terms "lateral", "longitudinal" and "radial" define the extension directions of layers, fibers and / or wires.

[0037] Thus, the lateral direction corresponds to the direction perpendicular to the extension surface of the layer. The lateral direction corresponds to the thickness of the layer. In addition, the lateral direction can be regarded as the radial direction of the fibers or wires of the elements constituting the layer. The lateral direction is represented by Figure 2 the axis T in.

[0038] Furthermore, the longitudinal direction corresponds to the extension direction of the fibers and / or wires of the elements constituting the layer. The fibers and / or wires extend along the surface of the elements constituting the layer, and the longitudinal direction can be based on two components represented by Figure 2 the axis X and axis Y in.

[0039] Figure 1 schematically shows an assembly that includes a component BA, in particular an aircraft component BA, in particular the leading edge of an aircraft wing or propeller, and the component BA is protected against icing by an anti-icing pad 1, in particular a thermoelectric pad 1.

[0040] The anti-icing pad 1 is attached to the outer surface 11 of the component BA that the anti-icing pad matches, for example, by gluing using an adhesive layer not shown.

[0041] As Figure 2 schematically shown in Figure 2 , the anti-icing mat 1 includes a multi-layer structure.

[0042] In particular, the multi-layer structure includes a stack of layers, especially according to Figure 2 the example shown, from the component BA to be protected against icing towards the external environment, the multi-layer structure includes the following stack of layers:

[0043] - A contact layer 2, which is intended to be in contact with the component BA to be protected (especially the leading edge), and has the functions of forming an electrical barrier and a thermal barrier;

[0044] - A heating layer 3, which is intended to be a heat source capable of providing de-icing and / or anti-icing functions for the component BA to be protected, especially through the Joule effect;

[0045] - An intermediate layer 4, which is intended to provide electrical insulation and thermal conductor functions;

[0046] - A reinforcement layer 5, which is intended to provide a protection function against impact for the anti-icing mat 1, especially for the heating layer 3;

[0047] - An outer layer 6, which is intended to provide a function of resisting the external environment (especially resisting the severe weather and temperature conditions that an aircraft may encounter).

[0048] The stack of different layers has a low thickness, usually less than 2 mm, especially less than 1.5 mm, and advantageously less than 1 mm.

[0049] If necessary, the multi-layer structure can be covered by a coating layer 7.

[0050] In particular, the anti-icing mat 1 including the multi-layer structure can have an electrical insulation resistance of at least 10 MΩ, especially at least 100 MΩ.

[0051] According to Figure 2 the exemplary embodiment shown, the contact layer 2 is arranged in the multi-layer structure so as to be inserted between the outer surface 11 of the component BA to be protected against icing and the heating layer 3.

[0052] The contact layer 2 is designed to be in contact with the component BA to be protected (especially the leading edge), and the function of the contact layer 2 is to form an electrical barrier and a thermal barrier.

[0053] In particular, the contact layer 2 can be made of a material having electrical insulation and thermal insulation properties.

[0054] Therefore, the contact layer 2 makes it possible to avoid an excessive contact temperature with the component BA to be protected against icing.

[0055] The material of the contact layer 2 can be an elastomer, a polymer, especially a thermoplastic polymer or a thermosetting polymer, especially an epoxy resin.

[0056] Alternatively, the contact layer 2 can be made of insulating foam.

[0057] According to a specific embodiment, the contact layer 2 can also be made of an insulating honeycomb structure. Alternatively or additionally, the contact layer 2 can also be made of a mixture of a polymer or an elastomer filled with glass beads, especially hollow glass beads.

[0058] Configured in this way, the contact layer 2 can prevent possible overheating of the component BA equipped with the anti-icing pad 1. In fact, due to the thermal insulation properties of the contact layer 2, the heat released by the heating layer 3 is directed towards the outer surface of the anti-icing pad 1, on which ice may form. According to the multi-layer structure, the outer surface of the anti-icing pad 1 is opposite to the contact layer 2 and thus opposite to the component BA to be protected against icing.

[0059] In addition, it is desirable to avoid any circulation of current between the heating layer 3 and the component BA.

[0060] In particular, the contact layer 2 can have a volume resistivity of at least 1E9 Ω·m, preferably greater than 1E10 Ω·m.

[0061] The thermal conductivity (also known as the transverse thermal conductivity) of the contact layer 2, which is considered perpendicular to the total extension plane of the contact layer 2, is less than 0.4 W / m·K at room temperature. Throughout this specification, room temperature refers to a temperature of about 20 °C.

[0062] The contact layer 2 can have a thickness of less than 1.5 mm, especially less than 1 mm, advantageously less than 0.7 mm. In addition, the contact layer 2 can have a thickness greater than 0.2 mm, especially greater than 0.3 mm, advantageously greater than 0.6 mm.

[0063] According to Figure 2 the exemplary embodiment shown, the heating layer 3 is arranged in the multi-layer structure so as to be inserted between the contact layer 2 and the intermediate layer 4.

[0064] The heating layer 3 is designed to provide a heat source capable of ensuring the de-icing and / or anti-icing function for the component BA to be protected through the Joule effect.

[0065] In particular, the heating layer 3 can be a resistive layer for Joule heating.

[0066] However, the heating layer 3 can be made of any heating device capable of generating a heat flux, especially, for example but not limited to, metal tracks, heating wires, conductive inks, fabrics or non-woven fabrics using fibers, etc.

[0067] For example, the heating layer 3 may integrate a grid of metal tracks through which an electric current flows to generate a heat flux by the Joule effect.

[0068] The metal tracks may be very close to each other to cover the surface as uniformly as possible. However, as will be understood more specifically from the following description, the longitudinal heat conduction ensured by the fibers and / or wires of the reinforcement makes the spacing between the metal tracks greater than the spacing of the metal tracks currently possible according to the prior art.

[0069] In particular, the metal tracks cover at least 50% of the surface of the heating layer 3, especially at least 70% of the surface of the heating layer 3.

[0070] The power supply electrical connection enables connection to a power supply to supply power to the metal tracks.

[0071] Typically, the heating layer 3 releases a heating power between 1 W / cm 2 and 5 W / cm 2 , especially between 2 W / cm 2 and 5 W / cm 2 , depending on whether the heating layer is operating in a cyclic mode or a continuous mode.

[0072] The heating layer 3 may have a thickness of less than 0.3 mm, especially less than 0.25 mm, advantageously less than 0.15 mm. In addition, the heating layer 3 may have a thickness greater than 0.015 mm, especially greater than 0,05 mm. Typically, the heating layer 3 may have a thickness of about 0.15 mm.

[0073] According to Figure 2 the exemplary embodiment shown, the intermediate layer 4 is arranged in the multi-layer structure to be inserted between the heating layer 3 and the reinforcement layer 5.

[0074] The intermediate layer 4 is designed to provide an electrical insulation and heat conductor function.

[0075] In particular, the intermediate layer 4 may be made of a composite material selected to have good electrical insulation and good heat conduction properties.

[0076] The intermediate layer 4 helps to direct the heat flux generated by the heating layer 3 to the outer surface of the anti-icing pad 1, that is, the intermediate layer 4 is opposite the contact layer 2 and thus opposite the component BA to be protected against icing.

[0077] In particular, the intermediate layer 4 may have a volume resistivity of at least 1E9 Ω·m, preferably greater than 1E10 Ω·m.

[0078] The thermal conductivity (also known as the transverse thermal conductivity) of the intermediate layer 4, determined according to the method described in standard ISO 8302 or ASTM C177 and considered perpendicular to the total extension plane of the intermediate layer 4, is greater than 0.4 W / m.K at room temperature, particularly greater than 0.6 W / m.K at room temperature, particularly greater than 0.8 W / m.K at room temperature, especially greater than 1.5 W / m.K at room temperature.

[0079] The intermediate layer 4 may have a thickness of less than 1.5 mm, particularly less than 1 mm, advantageously less than 0.7 mm. Additionally, the intermediate layer 4 may have a thickness greater than 0.2 mm, particularly greater than 0.3 mm. Generally, the intermediate layer 4 may have a thickness of approximately 0.4 mm.

[0080] As Figure 3 shown more specifically in

[0081] According to Figure 2 the exemplary embodiment shown, the reinforcing layer 5 is arranged in the multi-layer structure to be inserted between the heating layer 3 and the outer layer 6.

[0082] The reinforcing layer 5 is designed to provide the function of protecting the anti-icing pad 1, particularly the heating layer 3, from impacts (such as gravel, hail, maintenance-related impacts, etc.).

[0083] In particular, the reinforcing layer 5 may be made of a material that enables the heat flux generated by the heating layer 3 to circulate towards the outer surface of the anti-icing pad 1, that is, the reinforcing layer 5 is opposite to the contact layer 2 and thus opposite to the component BA to be protected against icing.

[0084] In particular, the reinforcing layer 5 may be presented, for example, in the form of a fabric, non-woven fabric (such as felt) or mesh reinforcement extending along the total extension plane of the reinforcing layer 5.

[0085] The thermal conductivity (also known as the transverse thermal conductivity) of the reinforcing layer 5, determined according to the method described in standard ISO 8302 or ASTM C177 and considered perpendicular to the total extension plane of the reinforcing layer 5, is greater than 0.4 W / m.K at room temperature, particularly greater than 0.6 W / m.K at room temperature, particularly greater than 0.8 W / m.K at room temperature, particularly greater than 1.5 W / m.K at room temperature.

[0086] More specifically, the reinforcing layer 5 may include fibers and / or threads. In such a configuration, the fibers and / or threads of the reinforcing layer may further have a longitudinal thermal conductivity greater than 0.6 W / m.K at room temperature.

[0087] The longitudinal thermal conductivity is the thermal conductivity considered in a direction parallel to the direction of extension of the fibres and / or threads. Thus, the longitudinal thermal conductivity of the fibres and / or threads corresponds to the thermal conductivity along the total extension plane of the reinforcing layer 5.

[0088] A longitudinal thermal conductivity greater than 10 W / m.K at room temperature homogenizes the temperature of the reinforcing layer 5 longitudinally, that is to say, homogenizes the temperature of the reinforcing layer 5 in the total extension plane of the reinforcing layer 5.

[0089] Alternatively, in order to ensure homogeneity, the longitudinal thermal conductivity can be greater than 50 W / m K, particularly along the fibre axis.

[0090] Advantageously, the radial conductivity of the fibres corresponds to the transverse conductivity of the anti-icing mat 1. Thus, the radial conductivity of the fibres must logically be equivalent to the radial conductivity of the intermediate layer 4 and the outer layer 6 described below.

[0091] This thermal conductivity is particularly important when the heating layer 3 consists of a network of metal tracks with a non-uniform heating surface. In fact, in this case, the heat flux emitted by the metal tracks of the heating layer 3 is longitudinally non-uniform.

[0092] Homogenization of the heat flux in the total extension plane of the reinforcing layer 5 makes it possible to achieve a higher de-icing or anti-icing efficiency, since the heat flux generated by the heating layer 3 to ensure the de-icing and / or anti-icing function diffuses over the entire surface of the anti-icing mat 1 without non-uniformity.

[0093] It should also be noted that the homogenization function provided by the reinforcing layer 5 (particularly in the form of a fabric, non-woven fabric, knitted fabric, mesh and / or unidirectional reinforcement, and combinations and / or stacks thereof) makes it possible to relax the constraints on the spacing of the tracks of the heating layer 3. Thus, heating metal tracks that are further spaced apart from each other can be used compared to the heating metal tracks currently possible in known solutions of the prior art.

[0094] Thus, the present invention provides the possibility of using techniques for manufacturing the heating layer 3, particularly heating resistors, in particular by additive manufacturing.

[0095] Preferably, the reinforcing layer 5 comprises a grid of woven, non-woven, knitted, meshed fibres and / or threads, and / or a unidirectional reinforcement (in particular carbon fibres made from an asphalt fibre precursor, in particular coal or petroleum pitch), and / or threads having a longitudinal thermal conductivity greater than 50 W / m.K at room temperature.

[0096] More preferably, the woven or meshed reinforcement of the reinforcing layer 5 comprises fibres having a longitudinal thermal conductivity greater than 120 W / m.K at room temperature.

[0097] The fibers and / or wires of the reinforcing layer 5 can be of different types, such as glass fibers, basalt fibers, silica fibers, metal wires, etc.

[0098] Preferably, the reinforcing layer 5 (especially in the form of a woven, non-woven or mesh reinforcement) is made of carbon fibers, which have the advantage of good thermal conductivity.

[0099] More preferably, the carbon fibers of the reinforcing layer 5 are made of coal or petroleum pitch. This production of carbon fibers enables the radial thermal conductivity to be greater than 0.6 W / m.K, especially greater than 10 W / m.K, and / or enables the longitudinal thermal conductivity to be greater than 50 W / mK, especially greater than 120 W / m.K.

[0100] According to another embodiment, the fibers of the reinforcing layer 5 include carbon fibers having a polyacrylonitrile (PAN) type precursor. Such an embodiment has a radial thermal conductivity greater than 1 W / m.K and a longitudinal thermal conductivity greater than 10 W / m.K.

[0101] It will also be noted that the reinforcing layer 5 can also participate in a protection function, a protection function against electrostatic discharge, which is also denoted by the acronym "ESD".

[0102] For example, in the case where the reinforcing layer 5 is made of a carbon fabric and / or contains a metal, the reinforcing layer 5 can be used for grounding aimed at ensuring the discharge of electrostatic charges.

[0103] In this hypothesis, the reinforcing layer 5 can at least partly contribute to lightning protection.

[0104] The reinforcing layer 5 can have a thickness less than 1.5 mm, especially less than 1 mm, especially less than 0.7 mm, advantageously less than 0.3 mm. In addition, the reinforcing layer 5 can have a thickness greater than 0.02 mm, especially greater than 0.05 mm. Generally, the reinforcing layer 5 can have a thickness of about 0.1 mm.

[0105] According to Figure 2 In the exemplary embodiment shown, the outer layer 6 is arranged in the multi-layer structure to be inserted between the reinforcing layer 5 and the coating layer 7.

[0106] Alternatively, the outer layer 6 is arranged in the multi-layer structure such that the outer layer 6 is disposed on the reinforcing layer 5 and in direct contact with the external environment.

[0107] The outer layer 6 is designed to provide a function of resisting the external environment (especially resisting the severe weather, temperature conditions and fluid jets that an aircraft may encounter).

[0108] In particular, the outer layer 6 can be made of an elastomer or polymer that resists the external environment (especially resisting the severe weather and temperature conditions that an aircraft may encounter).

[0109] In particular, the outer layer 6 resists erosion under the conditions defined by the standard sand dust RTCA-DO-160.

[0110] In addition, the outer layer 6 contributes to impact protection.

[0111] In addition, the outer layer 6 can also be a composition including fillers enabling the outer layer to dissipate static electric charges.

[0112] Furthermore, the outer layer 6 is thermally conductive and does not necessarily have electrical insulation properties.

[0113] The outer layer 6 can have a thickness less than 1.5 mm, particularly less than 1 mm, advantageously less than 0.5 mm. In addition, the outer layer 6 can have a thickness greater than 0.1 mm, particularly greater than 0.2 mm. Generally, the outer layer 6 can have a thickness of about 0.2 mm.

[0114] According to Figure 2 the exemplary embodiment shown, the coating layer 7 can be applied to the multi-layer structure to cover the multi-layer structure.

[0115] In particular, the coating layer 7 is designed to have properties resistant to the external environment and / or resistant to erosion, particularly under the conditions of the standard sand dust RTCA-DO-160.

[0116] In addition, the coating layer 7 can also be a composition including fillers enabling the coating layer to dissipate static electric charges.

[0117] In addition, applying the coating layer 7 on the multi-layer structure may require pre-coating an adhesion primer on the multi-layer structure, particularly on the reinforcing layer 5, or performing an adhesion treatment by a dry method (such as by plasma).

[0118] After being arranged in this way and according to the present invention, the anti-icing pad 1 has a total thickness less than 1.9 mm, particularly less than 1.5 mm, particularly less than 1 mm.

[0119] As previously mentioned, the intermediate layer 4 can be made of a composite material 40 including a matrix 42 and inclusions 41.

[0120] The matrix 42 is made of an electrically insulating elastomer. Such an elastomer is selected to have good tolerance within the typical operating temperature range of the anti-icing pad 1.

[0121] The maximum operating temperature of the anti-icing pad 1 is the temperature that the heating layer 3 can reach during the heat flux required to generate the de-icing cycle.

[0122] Since the intermediate layer 4 is in direct contact with the heating layer 3, one surface of the intermediate layer 4 in contact with the heating layer 3 must withstand the maximum operating temperature.

[0123] Since the heating layer 3 is covered by the intermediate layer 4, there is also an effect of heat flux accumulation at the interface between the heating layer 3 and the intermediate layer 4. The maximum temperature can generally be between 100 °C and 110 °C.

[0124] Preferably, the matrix 42 is made of a thermosetting polymer, in particular an elastomeric material or an epoxy resin.

[0125] However, the matrix 42 can be made of another type of polymer, for example, made of a thermoplastic polymer.

[0126] In order to obtain good resistance within the operating temperature range between the minimum temperature and the maximum temperature and to ensure suitable mechanical properties, it is particularly advantageous that the matrix 42 is made of a polymer selected from polyurethanes, nitriles, neoprene, silicone, fluorosilicone, and / or epoxides.

[0127] In particular, the matrix 42 can be made of a thermoplastic polymer, such as polyetheretherketone (also denoted by the acronym PEEK), polyetherketoneketone (also denoted by the acronym PEKK), polyetherimide (also denoted by the acronym PEI), polysulfone (also denoted by the acronym PSU), polyethersulfone (also denoted by the acronym PESU), polyphenylsulfone (also denoted by the acronym PPSU), polyamide-imide (also denoted by the acronym PAI), or polyphthalamide (also denoted by the acronym PPA).

[0128] This material particularly has the following advantages: it can withstand the contact temperature with the heating layer 3, can continuously generate a heat flux of about 100 °C, and is particularly beneficial for ensuring the de-icing and / or anti-icing function.

[0129] Advantageously, the material of the matrix 42 is suitable for being formed by a vulcanization method after incorporating the inclusions 41. This method can fix the position of the inclusions 41.

[0130] Another advantage of this vulcanization forming is that it can be co-vulcanized with another material of an adjacent layer (such as the heating layer 3 that needs to be in close contact).

[0131] In an embodiment where the heating layer 3 is made of a metal track or a heating wire, the metal track or the heating wire is advantageously coated with a primer that can ensure connection with the matrix 42.

[0132] In addition, it is entirely possible that there are different connection methods between different layers of the multi-layer structure of the anti-icing pad 1, such as adhesion, co-vulcanization, or more generally co-firing.

[0133] The matrix 42 includes inclusions 41. In particular, the inclusions 41 are made of a material having a high volume resistivity (particularly greater than 1E9 Ω·m, preferably greater than 1E10 Ω·m).

[0134] This resistivity of the inclusion 41 makes it possible to obtain a material whose total resistivity corresponds to the electrical insulation requirements of the intermediate layer 4, which intermediate layer 4 is arranged in direct contact with the heating layer 3.

[0135] Moreover, the inclusion 41 has a thermal conductivity greater than 1.5 W / m.K at room temperature, in particular higher than 20 W / m K.

[0136] This thermal conductivity of the inclusion 41 makes it possible to increase the thermal conductivity of the intermediate layer 4. Thus, this configuration makes it possible to better transmit the heat flux generated by the heating layer 3 towards the surface to be de-iced.

[0137] By increasing the transmission of the heat flux, it is possible to achieve the energy savings necessary to ensure the de-icing and / or anti-icing function of the component BA to be protected.

[0138] Moreover, the good thermal conductivity of the intermediate layer 4 makes it possible to reduce the cumulative effect of the heat flux at the heating layer 3. Thereby, it is possible to reduce the temperature to which the intermediate layer 4 is subjected in the vicinity of the contact region with the heating layer 3. This reduction in temperature in this contact region to some extent prevents the deterioration of the material of the matrix 42.

[0139] Therefore, the increased thermal conductivity makes it possible to increase the service life of the heating layer 3 and / or use other materials with less high-temperature resistance for manufacturing the matrix 42, provided that the surface temperature of the component BA to be protected remains within a reasonable range.

[0140] Advantageously, the material of the inclusion 41 is a ceramic with good thermal conductivity and electrical insulation.

[0141] Preferably, the inclusion 41 is made of boron nitride, aluminum nitride, aluminum oxide, or a composition of these fillers.

[0142] Other ceramics with different resistivity and thermal conductivity parameters can be used.

[0143] According to a particular embodiment, the volume fraction of the inclusion 41 in the matrix 42 is generally from 10% to 70%, in particular from 20% to 50%, and in particular from 30% to 50%.

[0144] Such a volume fraction makes it possible to maintain the mechanical properties of the matrix 42 for the shaping and use of the intermediate layer 4, while making it possible to utilize the thermal properties of the inclusion 41 to increase the overall thermal conductivity of the material.

[0145] An example of the manufacture of the composite material that can form the intermediate layer 4 will now be described.

[0146] The first step consists of providing a substrate for the formulation of the matrix polymer 42. Such a substrate is generally provided in the form of a plate, a flap or granules and does not include any solvent. For example, the starting material can be rubber.

[0147] In a second step, the substrate is mixed, for example, in an enclosed mixer with a plurality of propellers or in a cylindrical mixer (also known as an open mixer).

[0148] The elements of the substrate are heated by the shear effect that occurs during mixing.

[0149] During the second step, the substrate is transformed into a homogeneous viscous material.

[0150] In a third step, particles intended to form the inclusions 41 are added. Such particles are provided in powder form and may be agglomerated during the production or storage of such particles.

[0151] The particles are added during a third step consisting of a mixing step. The third step makes it possible to separate any agglomerates and to distribute the particles homogeneously in the viscous material intended to form the matrix 42 (in particular made of a polymer).

[0152] During a fourth step, when the inclusions 41 are distributed in the matrix 42, an intermediate layer 4 is formed, the thickness of which can be between 0.2 mm and 0.7 mm. Generally, the thickness of the intermediate layer 4 is approximately 0.4 mm.

[0153] The formation of the intermediate layer 4 can be carried out by calendering, extrusion, in particular by extruding a film in a flat die...

[0154] Subsequently, during a fifth step, the matrix 42 is shaped using a dedicated tool and then vulcanized in order to hold the inclusions 41 in place and to fix the geometry of the intermediate layer 4.

[0155] In some embodiments, an intermediate layer 4 can be formed in direct contact with the heating layer 3. In this case, co-vulcanization is carried out between the polymer matrix 42 and the heating layer 3. Such co-vulcanization makes it possible to ensure good mechanical and thermal contact between the intermediate layer 4 and the heating layer 3.

[0156] In order to test the intermediate layer 4 and more generally the structure of the anti-icing mat 1, a test device 400 as Figure 4 shown is used.

[0157] Advantageously, the anti-icing mat 1 comprising the contact layer 2, the heating layer 3, the intermediate layer 4, the reinforcement layer 5 and the outer layer 6 is tested.

[0158] The test device 400 comprises an electrically conductive reservoir 401 filled with a certain quantity of water 402, generally a metal reservoir.

[0159] Immerse a stack comprising at least a contact layer 2, in particular an electrically insulating intermediate layer 4 made of a composite material 40, and a heating layer 3 in a quantity of water 402.

[0160] Alternatively, immerse an anti-icing mat 1 comprising a contact layer 2, a heating layer 3, an intermediate layer 4, a reinforcing layer 5 and an outer layer 6 in a quantity of water 402.

[0161] Thus, two electrodes 411, 412 are connected to the heating layer 3 via a power supply line and establish an electrical connection 413 with a resistance measuring device 410 (such as an ohmmeter). The resistance measuring device 410 is electrically connected to a tank 401.

[0162] Apply a voltage, in particular a DC voltage of 500 V, between the reservoir 401 and the electrodes 411, 412 connected to the heating layer 3.

[0163] Preferably, the voltage applied during the test is twice the operating voltage of the de-icing and / or anti-icing device for the component BA to be protected against icing, and the operating voltage can be from 220 V to 230 V.

[0164] Alternatively, the operating voltage of the de-icing and / or anti-icing device for the component BA to be protected against icing can be supplied at 110 V.

[0165] Thus, the first test step comprises measuring the insulation resistance by means of the resistance measuring device 410.

[0166] If the following conditions are met, the result of the first test step is considered to be verified:

[0167] - The stack comprising the heating layer 3 is intact, i.e., no damage due to arcing is visible between the surface of the contact layer 2 and the heating layer 3 and / or between the surface of the outer layer 6 and the heating layer 3; and

[0168] - The insulation resistance measured by the resistance measuring device 410 is greater than 10 MΩ, in particular greater than 100 MΩ.

[0169] The value of the measured insulation resistance can be adjusted according to the specifications of the intended application.

[0170] In addition, in order to confirm the reliability of the material, multiple repeated tests can be carried out continuously.

[0171] Subsequently, the second test step comprises verifying the dielectric resistivity and the leakage current.

[0172] Figure 5 A test device 400 for the second test step is shown in. Figure 4 Elements common to the test devices are denoted by the same reference numerals and will not be described again.

[0173] The test device 400 comprises a leakage current measuring device 420 , for example in the form of an ammeter, electrically connected to electrodes 411 and 412 , which are connected to the intermediate layer 4 .

[0174] Furthermore, the test device 400 comprises a voltage source 430 electrically connected to the leakage current measuring device 420 and the reservoir 401. As an example, the voltage source 430 provides a voltage of at least 1500 V in an alternating current having a frequency between 50 Hz and 60 Hz.

[0175] In a second test step, the voltage is applied. To this end, the voltage is gradually increased for 20 seconds within a range from 0 V to twice the operating voltage of the de-icing and / or anti-icing device plus 1000 V. The resulting voltage is then maintained for one minute.

[0176] The results of the second test step are considered verified if the following conditions are met:

[0177] the stack comprising the heating layer 3 and the intermediate layer 4 is intact, i.e. no damage due to arcing is visible between components of the test device 400 and / or between the heating layer 3 and the intermediate layer 4;

[0178] - the stack including the heating layer 3 is intact, i.e. no damage due to arcing is visible between the surface of the contact layer 2 and the heating layer 3 and / or between the surface of the outer layer 6 and the heating layer 3; and

[0179] The leakage current measured by the leakage current measuring device 420 is less than 200 mA, in particular less than 50 mA, in particular less than 30 mA.

[0180] The leakage current value measured by the leakage current measurement device 420 may be adjusted according to the specifications of the intended application.

[0181] The intermediate layer 4 can be integrated into any functional layer stack that requires electrical insulation and thermal conduction.

[0182] exist Figure 1 In the case of the thermoelectric anti-icing pad 1 , the intermediate layer 4 arranged on the heating layer 3 improves the deicing performance and can reduce the heating temperature of the heating layer 3 .

[0183] Lowering the temperature of the heating layer 3 is beneficial for integrating the anti-icing mat 1 on a temperature-sensitive component, especially a composite component.

[0184] Furthermore, the matrix 41 is advantageously made of an elastomer, thereby enabling the intermediate layer 4 and the anti-icing mat 1 to be adapted to complex component shapes, in particular three-dimensional components, in particular non-expandable three-dimensional components.

[0185] Forming with an unvulcanized elastomer and then fixing the intermediate layer 4 by vulcanization. However, after vulcanization, the elasticity of the intermediate layer 4 can be maintained.

[0186] For the materials just described, other applications besides the thermoelectric anti-icing pad 1 are of course possible, such as radiators.

[0187] According to the present invention, different techniques can be used to assemble the different layers of the anti-icing pad 1.

[0188] In one possible embodiment, the contact layer 2 constituting the thermal barrier and the electrical barrier can be directly formed on the heating layer 3, in particular by spraying on the reinforcing layer 5.

[0189] Alternatively or additionally, the contact layer 2 comprises elastomer sheets superimposed manually or by automatic covering. The material of the contact layer 2 can be an elastomer, a polymer, which is in particular a thermoplastic polymer or a thermosetting polymer, in particular an epoxy resin.

[0190] Similarly, the intermediate layer 4 provides electrical insulation and thermal conductor functions and has a greater thermal conductivity than the contact layer 2 to direct the dissipation of the heat flux towards the external environment.

[0191] Then the reinforcing layer 5 can be assembled to the intermediate layer 4 and the outer layer 6, for example, by gluing.

[0192] The outer layer 6 can be directly formed on the reinforcing layer 5, in particular by spraying on the reinforcing layer 5.

[0193] In another possible embodiment, the respective layers of the multi-layer structure are superimposed on each other manually or by automatic covering and then assembled together by various assembly methods.

[0194] For various bonding operations, the surfaces to be bonded can be prepared by any bonding treatment, in particular by dry method or by plasma.

[0195] The method for manufacturing the anti-icing pad 1 can include at least the following steps used alone or in combination:

[0196] - The contact layer 2, the intermediate layer 4 and / or the outer layer 6 are calendered from an elastomer mixture, advantageously used in the original form during all steps of the manufacturing method;

[0197] - The heating layer 3 is preferably a heating resistor obtained by chemically cutting a metal strip, and the heating resistance value of the anti-icing pad 1 is controlled in this step;

[0198] - The heating layer 3 is covered with at least one primer so that it can be bonded to the elastomer during the vulcanization step, and the heating layer 3 can be composed of multiple components;

[0199] - Using a manufacturing tool, the geometry of which corresponds to the shape of the component BA to be protected against icing, the manufacturing tool being optionally covered with a non-stick coating;

[0200] - The reinforcing layer 5 is a fabric reinforcement adhered by adding a major type of chemical product in an aqueous solution or containing a solvent, by a dry method, by powder deposition, by plasma, etc.;

[0201] - Depositing the outer layer 6 on the manufacturing tool, especially manually or automatically;

[0202] - Depositing the reinforcing layer 5 on the outer layer 6, especially optionally pre-forming the reinforcing layer 5 in a fan shape to be able to fit the manufacturing tool;

[0203] - Depositing the intermediate layer 4 on the reinforcing layer 5;

[0204] - Depositing the heating layer 3 on the intermediate layer 4;

[0205] - Making an electrical connection, for example by welding;

[0206] - Depositing the contact layer 2 on the heating layer 3;

[0207] - Then manufacturing a vacuum bag on the multi-layer structure thus formed;

[0208] - Then subjecting the whole to vacuum vulcanization in an autoclave;

[0209] - At the end of vulcanization, a demolding step is carried out and various finishing operations are carried out, such as especially trimming operations;

[0210] - A coating layer 7 can be added on the outer layer 6;

[0211] - Subsequently, the anti-icing pad 1 thus formed can be assembled to the component BA to be protected, for example by a cold bonding method.

[0212] The anti-icing pad 1 thus manufactured can be added by gluing the contact layer 2 to the outer surface 11 of the component BA to be protected.

[0213] Other assembly techniques than gluing are also possible, such as co-curing or co-vulcanization, especially when the component BA to be protected is made of a composite material.

[0214] Before depositing the glue on the component BA to be protected against icing and / or on the contact layer 2, a bonding primer can be added, aiming at enabling at least one of the surfaces of the component BA or the contact layer 2 arranged on top of each other to undergo a surface preparation treatment, such as abrasion, primer deposition or any other dry or plasma bonding treatment.

[0215] In the foregoing description, for purposes of example, the component BA to be protected is the leading edge of an aircraft wing.

[0216] The anti-icing mat 1 according to the invention can be attached to any other aircraft component that requires anti-icing protection, such as an engine air intake, a turbine fairing, an aircraft or helicopter propeller blade, a propeller engine cone, a protective radome, etc.

[0217] It should be noted that the proposed multi-layer structure for the anti-icing mat 1 is particularly flexible and conformable. This multi-layer structure is capable of adapting to the different three-dimensional shapes that can be considered for the component BA.

[0218] In the case of the de-icing type of operating mode, the heating layer 3 is advantageously supplied in a cycle so as to be able to detach the ice that has formed on the outer surface of the anti-icing mat 1.

[0219] For example, in the case of the de-icing type of operating mode, power is supplied to the heating layer 3 at regular intervals for a determined period of time.

[0220] Generally, in the case of the de-icing type of operating mode, the power applied to the heating layer 3 is between 1 W / cm 2 and 3 W / cm 2 , particularly between 2 W / cm 2 and 3 W / cm 2 .

[0221] In the case of the anti-icing type of operating mode, the heating layer 3 is supplied continuously to permanently prevent any ice from forming on the component BA to be protected against icing.

[0222] Generally, in the case of the anti-icing operating mode, the power applied to the heating layer 3 can reach 5 W / cm 2 .

[0223] In the detailed description of the invention given above, the terms used should not be considered as limiting the invention to the embodiments set forth in the description just presented, but should be interpreted as including all equivalents within the scope of prediction that a person skilled in the art can reach by applying their common general knowledge to the embodiments just disclosed to them.

Claims

1. An anti-icing mat (1) for a component (BA), in particular for an aircraft component (BA), the mat comprising a multi-layer structure having at least one heating layer (3) capable of generating a heat flux, It is characterized in that The anti-icing mat at least comprises: - A contact layer (2) forming at least one thermal barrier between the heating layer (3) and the component (BA), and - At least one intermediate layer (4) and / or reinforcement layer (5) and / or outer layer (6), the at least one intermediate layer and / or reinforcement layer and / or outer layer being thermally conductive and arranged between the heating layer (3) and the external environment.

2. The anti-icing mat (1) according to claim 1, wherein, The intermediate layer (4) has electrical insulation and thermal conductivity properties.

3. The anti-icing mat (1) according to any one of the preceding claims, wherein, The reinforcement layer (5) is inserted between the intermediate layer (4) and the outer layer (6).

4. The anti-icing mat (1) according to any one of the preceding claims, wherein, The reinforcement layer (5) comprises a network of woven, non-woven and / or mesh fibres or threads.

5. The anti-icing mat (1) according to any one of the preceding claims, wherein, The reinforcement layer (5) is conductive and connected to ground.

6. The anti-icing mat (1) according to any one of the preceding claims, wherein, The outer layer (6) is inserted between the reinforcement layer (5) and the external environment.

7. The anti-icing mat (1) according to any one of the preceding claims, wherein, The outer layer (6) is coated with a coating layer (7).

8. The anti-icing mat (1) according to any one of the preceding claims, wherein, The thickness of the heating layer (3), the contact layer (2), the intermediate layer (4), the reinforcement layer (5) or the outer layer (6) is less than 1.5 mm, in particular less than 1 mm, in particular less than 0.7 mm.

9. The anti-icing mat (1) according to any one of the preceding claims, wherein, The thickness of the heating layer (3), the contact layer (2), the intermediate layer (4), the reinforcement layer (5) or the outer layer (6) is greater than 0.2 mm, in particular greater than 0.3 mm, in particular approximately 0.4 mm.

10. A component, said component comprising at least one part (BA) having an outer surface (11), in particular an aircraft (BA) part (BA), characterized in that, The outer surface (11) is covered by the anti-icing mat (1) according to any one of the preceding claims.

11. A method for mounting an anti-icing mat (1) according to any one of claims 1 to 9 on an outer surface (11) of a component (BA), in particular an aircraft component (BA), wherein, The contact layer (2) is glued or co-vulcanized to the component (BA).

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