Temperature control device for an aircraft

Abstract

Temperature control device (100) for an aircraft (102), wherein the temperature control device (100) has the following features: a first layer (104) and a second layer (106) opposite the first layer (104), wherein the first layer (104) is realized as a protective layer and the second layer (106) is formed as a carrier layer made of resin or pre-impregnated fibers; a heating layer (108) formed from a PTC thermistor material and arranged between the first layer (104) and the second layer (106); and a separating layer (110) arranged between the heating layer (108) and the second layer (106) and which does not adhere to either the heating layer (108) or the second layer (106), wherein the separating layer (110) is shaped to allow relative movement between the heating layer (108) and the second layer (106), in which the heating layer (108) slides along the separating layer (110).

Description

[0001] The present approach is based on a temperature control device for an aircraft according to the class of independent claims.

[0002] When heating elements are integrated into a composite material, the composite often consists of a substrate material, such as an FR4 plate or a plastic film made of, for example, PE, onto which a PTC thermistor material is applied. This application is usually done using a screen printing process. Optionally, a plastic film can then be bonded to the PTC material, or a protective coating can be applied to shield it from environmental influences. Interactions between the surrounding layers and the PTC material can lead to undesirable changes in the electrical resistance of the PTC material.

[0003] DE 10 2016 107 908 A1 discloses a heating device for an aircraft interior. A heating layer made of a resistive material can be arranged floating between a supporting structure and a deck structure.

[0004] US 2019 / 0 118 929 A1 discloses a composite sandwich panel with a perforated heating element positioned between two structural layers. The perforations in the heating element create channels through which resin can flow. The resin bonds the structural layers to the heating element. Disclosure of the invention

[0005] Against this background, the approach presented here introduces an improved temperature control device for an aircraft. The measures listed in the dependent claims enable advantageous further developments and improvements of the device specified in the independent claim.

[0006] A temperature control device for an aircraft is presented, comprising a first layer and a second layer opposite the first layer, a heating layer arranged between the first and second layers, and a separating layer arranged between the heating layer and the second layer. The separating layer is shaped to allow relative movement between the heating layer and the second layer.

[0007] The temperature control device can be installed, for example, in an aircraft. The first and second layers can be aligned parallel to each other. The heating layer can be implemented, for example, as a PTC thermistor. The separating layer can be shaped to mechanically decouple the heating layer and the second layer. Advantageously, the separating layer can protect the heating layer without altering its electrical resistance. If the second layer contains resin, for example, the separating layer can prevent the resin from adhering to the heating layer during the curing process.

[0008] According to one embodiment, the separating layer can be shaped to allow relative movement as shearing movement. Advantageously, this avoids a rigid connection between the second layer and the heating layer.

[0009] Furthermore, the separating layer can be in the form of a separating film or a separating lacquer. A separating film is easy to apply and can be implemented in a known manner with at least one non-adherent surface to allow relative movement between the heating layer and the second layer. The separating lacquer can, for example, consist of paraffin. This advantageously flattens any fiber structure of the second layer.

[0010] According to one embodiment, the separating layer, for example in the form of a separating film, can be made of a plastic. The plastic can be, for example, perfluoroethylene propylene (FEP), FPA, or polytetrafluoroethylene (PTFE). Thus, common materials can be used for the separating film.

[0011] The separating layer can have at least one non-adherent surface. This allows, for example, the heating layer to slide along the separating layer. Additionally or alternatively, the separating layer can have a viscosity of less than 1000η. This allows the separating layer to deform, enabling relative movement between the separating layer and the heating layer.

[0012] The separating layer can have a thickness of more than 0.01 mm, preferably more than 0.02 mm. Advantageously, the separating layer can thus flatten the fiber structure of the temperature control device.

[0013] The second layer is designed as a support layer, and the first layer is designed as a protective layer. A support layer can be a plate, for example made of a flame-retardant material, or a film. Therefore, the temperature control device can be either flexible or rigid.

[0014] The second layer is made of resin or pre-impregnated fibers. These pre-impregnated fibers can also be referred to as prepreg. Prepreg, for example, stands for "pre-impregnated" and can refer to textile fiber-matrix semi-finished products pre-impregnated with reactive resins. This allows the use of common composite materials, while the separating layer can prevent any potentially negative interactions between the second layer and the heating layer.

[0015] The heating element is made of a thermistor material. This advantageously ensures better electrical conductivity at low temperatures than at high temperatures, resulting in simple temperature control.

[0016] Furthermore, the heating layer can have a plurality of through-holes, and the separating layer a further plurality of through-holes, to establish direct contact between the first and second layers. The plurality of through-holes and the further plurality of through-holes can, for example, be arranged in a straight line, one above the other. Advantageously, this retains the possibility of achieving mechanical strength or preventing slippage of the individual layers. Nevertheless, relative movement between the separating layer and the heating layer is still possible outside of the through-holes.

[0017] According to one embodiment, the temperature control device can be designed as a base plate or wall segment for an aircraft. This means that the temperature control device can be implemented, for example, in an aircraft, but also, for example, in a vehicle or as underfloor heating in a building. Advantageously, this allows an area, and thus a room, to be heated.

[0018] In the following description of favorable embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and acting similarly, without repeating these elements.

[0019] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows: Fig. 1 a schematic representation of a temperature control device according to an embodiment for an aircraft; Fig. 2 a schematic cross-sectional representation of a temperature control device according to an exemplary embodiment; Fig. 3 a schematic cross-sectional view of a temperature control device according to an exemplary embodiment; and Fig. 4 a flowchart of a method for manufacturing a temperature control device according to an exemplary embodiment.

[0020] Fig. Figure 1 shows a schematic representation of a temperature control device 100 according to an exemplary embodiment. For illustrative purposes only, the temperature control device 100 is used in the interior of an aircraft 102. The temperature control device 100 is, for example, designed as a wall segment or a floor panel of the aircraft 102 and can also be used as a heater.

[0021] The temperature control device 100 has a first layer 104 and a second layer 106 opposite the first layer 104, which, according to this embodiment, are formed from pre-impregnated fibers or resin. The first layer 104 is, for example, configured as a support layer. The second layer 106 is, for example, configured as a protective layer. Alternatively, the first layer 104 is configured as a protective layer and the second layer 106 as a support layer. Furthermore, the temperature control device 100 has a heating layer 108, which can also be referred to as a heating element or PTC heating element. According to this embodiment, the heating layer 108 is configured as a PTC thermistor. This enables good electrical conductivity at low temperatures. The heating layer 108 is arranged between the first layer 104 and the second layer 106.Furthermore, the temperature control device 100 has a separating layer 110 arranged between the heating layer 108 and the second layer 106. According to this embodiment, the layers 104, 106, the heating layer 108, and the separating layer 110 are aligned parallel to one another, so that the temperature control device 100 is formed as a stacked composite. The separating layer 110 is shaped to allow relative movement, for example, a shearing movement, between the heating layer 108 and the second layer 106. The separating layer 110 is, for example, formed as a separating film or a separating lacquer. According to this embodiment, the separating layer 110 has a thickness that is, for example, between 0.02 mm and 0.04 mm. According to another embodiment, the separating layer 110 has a thickness of at least 0.025 mm.

[0022] According to one embodiment, the temperature control device 100 is designed as a composite component, which can be used, for example, in lightweight constructions. Decoupling of the layers 104, 106, and in particular the second layer 106, from the heating layer 108 is achieved.

[0023] According to this embodiment, the separating layer 110, which is also referred to as a plastic film, has a mandatory mechanical separating effect. It adheres neither to the heating layer 108 nor to any of the layers 104, 106, which may be made of resin, and thus an (inseparable) connection between the resin and the heating layer 108 is prevented.

[0024] In summary, the approach presented here does not create a mechanical connection between the second layer 106 and the heating layer 108. Therefore, according to this embodiment, no mechanical stresses caused by thermal expansion are transferred to the heating layer 108. Additionally, any chemical influence of the second layer 106 on the heating layer 108 is prevented. Furthermore, the separating layer 110 mitigates the strong pressure exerted by a glass or aramid fiber structure on the heating layer 108, for example, if the second layer 106 has such a structure. This results in greater process reliability, for example during manufacturing, and increased resistance to very high ambient temperatures.

[0025] The advantages achievable with the presented approach are that the separating layer 110 prevents altered properties of the PTC material, such as increased electrical resistance. Adhesion to the PTC material of the heating layer 108 can also be avoided. Thus, the approach presented here offers a means of establishing a separating connection to the heating layer 108. Furthermore, the approach advantageously prevents the pressing of a fabric structure into the potentially soft PTC material of the heating layer 108 and the resulting change in electrical resistance during a curing process, thereby ensuring a constant electrical resistance and preventing changes in the length of the PTC heating element of the heating layer 108.This also prevents a permanent increase in electrical resistance caused by high ambient temperatures, for example above 85°C above a PTC cutoff point (approximately 65°C). Advantageously, a constant heating output can be achieved. Furthermore, mechanical stresses caused by thermal expansion can be avoided, and resistance to very high ambient temperatures is increased.

[0026] According to this embodiment, the heating layer 108 is connected to a voltage source 116 via a first interface 112 and a second interface 114, for example via a first line 118 and a second line 120. This allows a current to be passed through the heating layer 108 to convert electrical energy into thermal energy. According to one embodiment, the voltage source is designed to provide a constant voltage U. The heating power P is given by: P=U*I

[0027] From the relationship U=R*I it follows that: P=U2 / R

[0028] Here, I represents the current flow through the heating layer 108 and R represents the electrical resistance of the heating layer 108.

[0029] According to an alternative embodiment, the separating layer 110 is arranged between the first layer 104 and the heating layer 108, or a further separating layer 110 or a different type of protective layer is arranged between the first layer 104 and the heating layer 108. If the temperature control device 100 has a composite structure, the separating layer 110, or optionally two separating layers 100, decouples the resin of the prepreg layers, here layers 104 and 106, of the composite structure from the PTC material of the heating element of the heating layer 108.

[0030] Fig. Figure 2 shows a schematic cross-sectional view of a temperature control device 100 according to an exemplary embodiment. The temperature control device 100 shown here can correspond to the temperature control device 100 as described in one of the Fig. 1 or Fig. 2 was described.

[0031] A schematic layer structure of the heating layer 108, in the form of a PTC heating element between the two layers 104 and 106, is shown. The two layers 104 and 106 can be prepreg layers or resin in which the PTC heating element is embedded. The separating layer 110 is implemented as a release film or release varnish.

[0032] According to one embodiment, composite release films without an adhesive coating, such as FEP, FPA, or PTFE, are suitable as the release layer 110. Alternatively, the release layer 110 is implemented as a release varnish, which can also be referred to as an anti-stick varnish. The release varnish is, for example, a paraffin film which, according to this embodiment, permanently separates the second layer 106 from the heating layer 108. According to an alternative embodiment, the release varnish is applied by a screen printing process.

[0033] Fig. Figure 3 shows a schematic cross-sectional view of a temperature control device 100 according to an exemplary embodiment. The temperature control device 100 shown here can be compared to the one described in Figure 3. Fig. The temperature control device 100 described in Section 2 is identical. The only difference is that the heating layer 108 and the separating layer 110 are not continuous, but rather have a further plurality of through-openings 301, 302. According to this embodiment, this serves to establish direct contact between the first layer 104 and the second layer 106. In this embodiment, the further plurality of through-openings 302 of the separating layer 110 is located opposite the plurality of through-openings 301 of the heating layer 108. Alternatively, the heating layer 108 and the separating layer 110 each have only one through-opening 301, 302. If at least one of the layers 104, 106 contains resin, a rigid connection between the layers 104, 106 can be created through the at least one through-opening 301, 302 during the resin curing process.

[0034] According to one embodiment, the separating layer 110 is perforated, just as the heating layer 108 is perforated, in order to achieve mechanical strength in the component. This avoids a problem that could occur with an unperforated heating layer 108, which could split the temperature control device 100 in two and thus reduce its strength.

[0035] Fig. Figure 4 shows a flowchart of a method 400 for manufacturing a temperature control device according to an exemplary embodiment. This means that a temperature control device can be manufactured by method 400, as described in the Fig. 1, Fig. 2 to Fig. 3 was described.

[0036] Method 400 comprises a stacking step (402) and an assembly step (404). In stacking step 402, the first layer, the second layer, the heating layer, and the separating layer are stacked. The heating layer is positioned between the first and second layers, and the separating layer is positioned between the heating layer and the second layer. In assembly step 404, the first layer, the heating layer, the separating layer, and the second layer are joined together. The separating layer is selected such that, after assembly, it allows relative movement between the heating layer and the second layer.

[0037] If an embodiment includes an “and / or” connection between a first feature and a second feature, this is to be read as meaning that the embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment either only the first feature or only the second feature.

Claims

[1] Temperature control device (100) for an aircraft (102), wherein the temperature control device (100) has the following features: a first layer (104) and a second layer (106) opposite the first layer (104), wherein the first layer (104) is realized as a protective layer and the second layer (106) is formed as a carrier layer made of resin or pre-impregnated fibers; a heating layer (108) formed from a PTC thermistor material and arranged between the first layer (104) and the second layer (106); and a separating layer (110) arranged between the heating layer (108) and the second layer (106) and which does not adhere to either the heating layer (108) or the second layer (106), wherein the separating layer (110) is shaped to allow relative movement between the heating layer (108) and the second layer (106), in which the heating layer (108) slides along the separating layer (110). [2] Temperature control device (100) according to claim 1, wherein the separating layer (110) is formed as a separating film or as a separating lacquer. [3] Temperature control device (100) according to one of the preceding claims, wherein the separating layer (110) has a thickness of more than 0.01 mm, preferably more than 0.02 mm. [4] Temperature control device (100) according to one of the preceding claims, wherein the heating layer (108) has a plurality of through-openings (301), and wherein the separating layer (110) has a further plurality of through-openings (302) to establish direct contact between the first layer (104) and the second layer (106). [5] Temperature control device (100) according to one of the preceding claims, wherein the temperature control device (100) is formed in the form of a base plate or a wall segment for an aircraft (102).

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