ELECTRIC SURFACE HEATING WITH SELF-LIMITING HEATING CABLE

Description

[0001] The invention relates to an electric surface heating system for the construction industry with a self-limiting heating cable. The invention further relates to the manufacture of an electric surface heating system. The invention also relates to a self-limiting heating cable for an electric surface heating system and the manufacture of a self-limiting heating cable.

[0002] The invention can therefore relate to the technical field of heating systems, in particular electric surface heating systems.

[0003] Self-limiting (or self-regulating) heating cables are used in heating systems to prevent overheating and the resulting hazards. Figures 11a and 11bFigure 210 shows a conventional self-limiting heating cable 210 in which two low-resistance parallel conductors 211, 212 are connected by means of a self-regulating material 215, which has a higher resistance than the conductors 211, 212. When energy is supplied in the form of an electric current, the self-regulating material 215 heats up (heating effect). The self-regulating material 215 is designed such that its resistance increases very sharply with increasing temperature (heating). In this way, the maximum temperature of the heating cable 210 is limited.

[0004] Figure 11aFigure 1 shows a cross-section through the self-limiting heating cable 210. In general, self-limiting heating cables 210 are designed as flat cable heating cables in which the longitudinal conductors 211, 212 are arranged parallel to each other (with the self-limiting material 215 in between), resulting in a width direction y perpendicular to the length direction x of the cable, which is significantly larger than the corresponding height direction z (which is oriented perpendicular to the length direction and width direction).

[0005] The typical flat ribbon heating cable design, as seen in the prior art, is related to the functionality of a self-limiting cable: the wide design of the high-resistance conductor in the web between the two low-resistance conductors creates a homogeneous zone in which a uniformly distributed current is generated per unit area. This is important for the operation of such a cable because it ensures that (with uniform heat dissipation) all parts of the system simultaneously reach the same temperature difference above the ambient temperature. If a single hotspot in the cable were to regulate the entire rest of the heating system during constant load changes between on and off states, the system's reliability could decrease. This would be due to localized material fatigue at the corresponding points, resulting in excessively high temperatures.

[0006] Figure 11bThis shows that, according to the prior art, a self-limiting heating cable 210, due to its flat ribbon construction, has the property of being able to bend essentially only in one bending direction or axis (across the width direction y). Bending along the height direction or axis z would cause the self-limiting heating cable 210 to buckle. The typical buckling of a flat ribbon heating cable arises from its internal structure (electrical conductors are less elastic than electrical insulation) and from the cable geometry (the flat ribbon's width is greater or much greater than its height; y > z, or y >> z). Both of these factors cause the cable to deflect in a different direction when bent around the bending axis z.

[0007] As in Figure 12As shown, conventional self-limiting heating cables 210 can be installed in electric surface heating systems 200. However, because the self-regulating heating cables 210 are designed as flat ribbon heating cables (and have the corresponding bending properties, see above), they are mounted vertically (standing upright), i.e., with the width of the flat ribbon heating cable oriented in the height direction of the surface heating system 200. This is to prevent the self-limiting heating cable 210 from bulging (as described above) when bent. Therefore, to use such a self-limiting heating cable 210 in an electric surface heating system 200 and to achieve a curved (serpentine or meandering) installation of the self-limiting heating cable 210 across the surface, such systems 200 are implemented with vertically arranged self-limiting heating cables 210.

[0008] JP 2001 267049 A describes a self-limiting heating cable with a circular cross-section that can be deformed in several directions. To achieve a circular cross-section, the conductors are twisted together. Each conductor is cylindrically sheathed in self-limiting material.

[0009] US Patent 2015 / 257205 A1 describes a heating element that can be deformed with exceptional flexibility. To achieve this flexibility, conductive fibers are wound parallel to each other around a core in the cord-like heating element and covered with an insulating film containing silicone. The described heating element does not possess self-limiting properties.

[0010] It is an object of the present invention to provide an electric surface heating system which is particularly safe (e.g. with regard to overheating) and at the same time particularly thin (and therefore particularly flexible and space-saving to install).

[0011] This task is solved using the subject matter of the independent claims. Advantageous configurations arise from the dependent claims.

[0012] According to one aspect, an electric surface heating system for installation in the construction sector is described. The electric surface heating system comprises: i) a self-limiting heating cable, and ii) a support structure which is formed along two principal directions of extension (longitudinal direction x and lateral direction y) and spans a support plane. At least one section of the self-limiting heating cable (or the entire cable) is arranged in a curved position on and / or in (e.g., surface-mounted or embedded) the support structure (or its support material). The height of the curved section of the self-limiting heating cable (in particular, the height of the electric surface heating system) is 15 mm or less in a vertical direction z, which is oriented perpendicular to the two principal directions of extension (x, y).

[0013] According to another aspect, a method for manufacturing an electric surface heating system for the construction sector is described. The method comprises: i) providing a self-limiting heating cable, ii) providing a support structure which is formed along two principal directions of extension and spans a support plane, iii) bending at least one section of the self-limiting heating cable, and iv) arranging at least the bent section of the self-limiting heating cable on and / or in the support structure such that the height of the bent section of the self-limiting heating cable in a vertical direction oriented perpendicular to the two principal directions of extension is 15 mm or less.

[0014] According to another aspect, a self-limiting heating cable for an electric surface heating system is described, comprising: i) a first conductor and a second conductor, each exhibiting a first resistance. The first and second conductors are arranged essentially parallel to each other in the self-limiting heating cable; ii) a self-limiting material located between the first and second conductors, exhibiting a second resistance that is higher than the first resistance and is temperature-coupled. The self-limiting heating cable has, at least in sections, a bending radius that is 30 times (particularly 20 times, and further specifically 10 times) or less than the largest diameter of the self-limiting heating cable (in cross-section).Additionally or alternatively, the self-limiting heating cable is bendable at least section by 90° (especially 180°) or more in two mutually perpendicular spatial directions (e.g. height direction and width direction of the self-limiting heating cable) (especially without (significant) bulging).

[0015] According to another aspect, a method for manufacturing a self-limiting heating cable for an electric surface heating system (in particular a self-limiting heating cable as described above) has been carried out.The method comprises: i) arranging two linear conductors, each having a first resistance, substantially parallel to one another, and ii) providing a self-limiting material between the first linear conductor and the second linear conductor, which has a second resistance that is temperature-coupled and higher than the first resistance, such that a) the self-limiting heating cable has, at least in sections, a bending radius that is 30 times (in particular 20 times, and further in particular 10 times) or less than the largest diameter of the self-limiting heating cable (in cross-section), and / or b) the self-limiting heating cable is bendable, at least in sections, by 90° (in particular 180°) or more in two mutually perpendicular spatial directions (in particular without significant bulging).

[0016] Within the scope of this document, the term "electric surface heating" (ESH) can be understood to mean, in particular, a device that emits heat energy when electrical energy is supplied to it. Preferably, the EFH is planar, i.e., it has two principal directions of extension (longitudinal direction x and lateral direction y). An EFH can have a heating element, e.g., a heating wire, a heating cable, a heating film, or a heating surface. In a simple embodiment, an EFH can be implemented by a planar heating wire through which an electric current flows, causing it to heat up and emit heat to the surroundings. In another embodiment, a heating cable is used as the heating element. This can be arranged on or within a carrier material of a support structure (e.g., a carrier film).In a preferred example, a heating cable, particularly in a curved, and especially meandering, arrangement, can be attached to or embedded in a carrier material. For example, the carrier structure can be designed as a film, which can then be transported on rolls. To install the electric surface heating cable as a wall, ceiling, or floor covering, the rolls can then be unrolled and secured. In one embodiment, the installed electric surface heating cable can be covered with a floor covering, e.g., parquet, or with wallpaper. Electric surface heating systems can be used in the construction sector, e.g., in house and building construction. In one example, the term "construction sector" excludes industrial or aviation applications.

[0017] Within the scope of this document, the term "support structure" can be understood as a planar structure (e.g., in the form of a film) suitable for serving as a support for a heating element (e.g., a heating cable). The support structure comprises a substrate material into which a heating element can be embedded and / or on which a heating element can be arranged. The substrate material can, for example, comprise at least one of the following materials: i) cut polystyrene sheets (or similar insulating material), ii) insulating elastomeric foams (or inorganic structured insulating materials as a substrate) with a provision for inserting or attaching the heating element, iii) polymer clips, which are either mounted directly to the floor (analogous to clips used in underfloor heating systems), iv) planar plastic sheets / films that are structured by means of a thermoforming process in such a way that heating elements can be inserted, v) heat spreaders (e.g.,...)B. Aluminum plates, bent in such a way that heating elements can be inserted). Furthermore, foil-like and grid-like support structures are suitable, on which a heating element can be attached (and which can possibly be transported as rolled goods).

[0018] In this context, the term "electric surface heating system" can refer to a system that, in addition to the actual electric surface heating element (ESH), includes other components associated with it. These include, for example, installation aids, heat spreaders, mechanical fixings, control systems, etc. Furthermore, it can also include components in the immediate vicinity, such as floor insulation, electrical shielding, floor covering, sensors, power supply, etc. The electric surface heating system can also include a (non-transparent) covering material that (at least partially) covers the EFH. Finally, an electric surface heating system can include a heating component-associated element. In this case, the heating component-associated element can be electrically connected to a heating component of the electric surface heating system via a connecting element.

[0019] Within this document, the term "heating component" can refer specifically to one or more heating elements and / or one or more self-limiting heating elements. A heating component can be, for example, a heating cable or a grid structure consisting of multiple rod-shaped heating elements. Within this document, the term "heating element" can refer specifically to an element that is particularly suitable for transferring heat to the surroundings when electrical energy is supplied. A heating element can, for example, comprise a heating wire, a heating cable, a heating film, or a heating surface. A heating element can also be implemented, for example, by a copper trace. Within this document, the term "heating cable" can refer to a cable that is particularly suitable for transferring heat to the surroundings when energy is supplied in the form of electricity, or when the cable is electrically connected.Within the scope of this document, the term "heating cable" may also include heating wires and heating tapes. A heating component may, in particular, be electrically connected to a heating component-associated element, especially via a connecting element.

[0020] Within the context of this document, the term "heating component-associated element" can refer to any element that can be connected to a heating component of an electric surface heating system via an electrically conductive connection (e.g., a connecting element). This heating component-associated element could be, for example, a supply conductor, a power cable, a sensor, an electrical connector to a socket and / or a fuse box, or a control connection. Furthermore, the heating component-associated element could also be another heating component or another electric surface heating system. A surface heating system could also be a first surface heating module, and the heating component-associated element could be a second surface heating module, with both modules being electrically connected to each other via the connecting element.The heating component-associated element can have a conductor with a terminal, whereby this terminal can be electrically connected to a terminal of the heating component. In particular, this connection can be made within the connection area of ​​a connecting element.

[0021] Within the scope of this document, the term "connecting element" can refer in particular to any element suitable for electrically connecting a heating component of an electric surface heating system and a heating component-associated element (or its connecting conductor) in a connection area. The connecting element can be connectable to (and / or coupled with) an electric heating component (e.g., a heating cable, a heating film, etc.) of the electric surface heating system. Additionally or alternatively, the connecting element can be connectable to (and / or coupled with) a heating component-associated element (e.g., a supply line, a control connection, a sensor (especially one connected by a connecting cable), another heating component, etc.). The connection can, in particular, involve the (permanent) integration of the connecting element into / onto the electric heating component and / or into / onto the heating component-associated element.The connecting element can have a connection area in which the electrical heating component can be electrically connected to the heating component-associated element in a connected state. The connecting element can have a cavity that is associated with (or located in / on) the connection area and into which a waterproof material (e.g., liquid or gel-like) can be introduced (and / or is introduced). Furthermore, the connecting element can have a boundary structure (e.g., an outer shell or a box with a lid) that is configured to delimit the cavity such that the connection area is waterproof (in particular, immersion-proof) in the connected state (in particular, the boundary structure presses the waterproof material (e.g., as a gel) within the cavity against the interconnected terminals of the heating component and the heating component-associated element).In another example, the connecting element can have a positioning structure (e.g., a connecting structure) which is configured to a) provide the connection state when a position safety criterion is met, and b) not provide the connection state when the position safety criterion is not met.

[0022] Within the context of this document, the term "cable" can refer to an electrically conductive conductor (or supply conductor). The term "cable" can refer to a stranded wire or a solid conductor. In particular, the electrically conductive conductor may be at least partially surrounded by insulating material. A cable may extend in a longitudinal direction x and, in cross-section, have a lateral direction y and a vertical direction z. In the case of a round cable, the lateral and vertical directions may be essentially the same. In the case of a ribbon cable, the lateral direction may be greater (in particular, significantly greater) than the vertical direction.

[0023] Within the context of this document, the term "self-limiting heating cable" (or self-regulating cable) refers to a specific embodiment of a heating cable (in particular, the term "self-limiting heating cable" excludes an ordinary heating cable). The term "self-limiting heating cable" can, in particular, refer to a heating cable with coupled and / or integrated temperature control. A self-limiting heating cable can be configured such that the heating is reduced or completely switched off above a certain temperature. The self-limitation may therefore be absolute in one example, while in another it may not be absolute (e.g., the self-limitation is such that the temperature increases only very slightly beyond this point). A self-regulating heating cable preferably consists of two substantially parallel conductors (supply conductors) or heating wires embedded in a self-limiting material.In one embodiment, the self-limiting material consists of a cross-linked polymer doped with carbon particles. As the operating temperature rises, the polymer expands due to molecular expansion, and the distances between the carbon particles increase. The resistance in the cable increases, and the heat production of the cable decreases. Upon cooling, this process reverses, and heat production increases again. In another example, a self-limiting material with a high PTC (positive temperature coefficient) resistance (e.g., polycrystalline ceramic) is used. In principle, materials with a (nearly) abrupt increase in resistance at a limiting temperature can be suitable as self-limiting materials.

[0024] According to an exemplary embodiment, the invention is based on the idea that a reliable (in particular safe) and at the same time particularly flexible and space-saving electric surface heating system can be provided if a self-limiting heating cable (which ensures safety and reliability) is provided in a height-adapted manner in the support structure of the electric surface heating system (e.g. arranged on or embedded in) such that the height of the self-limiting heating cable (and thus also the height of the electric surface heating system) is no more than 15 mm (in particular 10 mm, further in particular 5 mm).

[0025] One of the main advantages of electric underfloor heating is its very low profile, measured in millimeters. However, this profile increases significantly when using self-limiting heating cables, because the vertically oriented (standing) self-limiting flat ribbon heating cable requires considerable space (or expansion) in the vertical direction (see discussion above).

[0026] It has now been surprisingly discovered that an electric radiant heating system with a height-adjustable, self-limiting heating cable functions just as reliably and safely, but offers the crucial advantage of being exceptionally thin, thus enabling flexible and space-saving installation. It is now therefore possible to install a very thin electric radiant heating system across a wide area while still utilizing the benefits of a self-limiting heating cable.

[0027] The following describes exemplary embodiments of the invention.

[0028] According to one embodiment, the height of the bent section of the self-limiting heating cable is 10 mm or less (more specifically, 8 mm or less, and more specifically, 5 mm or less). This has the advantage of providing a particularly thin (and therefore also particularly flexible and robust to install) electric surface heating system, which nevertheless allows the advantageous use of a self-limiting heating cable (and the associated safety).

[0029] According to the invention, the self-limiting heating cable has, at least in sections, a bending radius that is 30 times (in particular 20 times, further in particular 10 times, further in particular 5 times) or less than the largest diameter (in particular width and / or height) of the self-limiting heating cable in cross-section. This has the advantage that a particularly flexible self-limiting heating cable can be installed flexibly and in a space-saving manner in an electric surface heating system.

[0030] In this context, the term "bending radius" can refer in particular to the radius to which a cable can be bent without damaging it (including kinking or buckling). The smaller the bending radius, the greater the corresponding flexibility of the cable or material (at least in sections). For example, if the diameter of a round cable is 1 cm, its bending radius in a particularly preferred embodiment would be 10 times that diameter, i.e., 10 cm, or less.

[0031] According to the invention, the self-limiting heating cable is bendable at least section by 90° (in particular 180°) or more in the principal directions of extension (in particular the longitudinal direction x and the lateral direction y) and / or the vertical direction (z) (in particular without buckling). This also has the advantage that a particularly flexible, self-limiting heating cable can be installed flexibly and in a space-saving manner in an electric surface heating system.

[0032] This design enables efficient installation of the self-limiting heating cable or electric surface heating, because the self-limiting heating cable can be flexibly bent and laid within the support plane of the electric surface heating (without increasing its height).

[0033] According to a further embodiment, the self-limiting heating cable has: i) a first area (which is specifically designed for heating) and a first bending property (e.g., flexibility, elasticity), and ii) a second area (which is specifically not designed for heating) and a second bending property. The first bending property and the second bending property are different from each other. In particular, the second bending property exhibits higher elasticity (e.g., with respect to the modulus of elasticity) than the first bending property.

[0034] In one embodiment, the first and second sections are alternately (in alternating sequences) provided longitudinally during cable manufacturing. The first section corresponds to a design similar to a conventional (self-limiting) heating cable. The second section, in turn, has no or reduced heating power but allows for high flexibility, such as predominantly warp-free bending (e.g., by 180°).

[0035] According to another embodiment, the self-limiting heating cable has a waterproof (in particular, immersion-proof or suitable for immersion in water) insulating layer. This can offer the advantage that the electric surface heating remains safe and reliable even under difficult installation conditions.

[0036] Within the context of this document, the term "waterproof material" can refer to a material that possesses a watertight insulating property. For example, if an electrical connection between two terminals is completely surrounded (or insulated) by the watertight material, water cannot penetrate to the electrical connection. Watertight materials can include, in particular, materials used for sealing, water displacement, moisture insulation, corrosion protection for electrical conductors, oxygen and / or water (vapor) diffusion barrier properties (with respect to corrosion), corrosion protection of an underlying (copper) conductor (e.g., through a component that functions like chemical tinning), and the reduction of biological growth (biofilm formation). The watertight material may preferably be liquid or gel-like (at room temperature). Furthermore, the material may, for example,The material can be a plastic, in particular a synthetic resin, or silicone. Furthermore, the waterproof material can consist of at least two material components which only form the waterproof material when mixed. In this context, the term "waterproof" can refer to, for example, a water resistance rating of IP (international protection) 65, while the term "submersible" can refer to a water resistance rating of IP 68 up to a water depth of 1 meter.

[0037] By encasing the heating cable with a waterproof insulating material, the associated electrical system (electric surface heating system) can be made watertight and also submersible. By selecting suitable insulating materials (e.g., polyurethanes), sufficient moisture insulation can also be achieved for permanent immersion in water. This can be advantageous for installations with a high risk of humidity, as it reduces the long-term corrosion of the low-resistance conductors. In one embodiment, the insulating layer can also be a gel.

[0038] According to another embodiment, the self-limiting heating cable has an electrically insulating layer (at least partially surrounding the self-limiting material). In particular, the electrically insulating layer comprises a material with high thermal conductivity. The insulating material can be a ceramic material, e.g., aluminum hydroxide. This can have the advantage of enabling particularly efficient heat distribution, even if, for example, the diameter of a self-limiting heating cable is reduced.

[0039] For example, a material with very high thermal conductivity, yet still insulating, can be incorporated into the insulation (or insulating layer) of the heating cable. It has been shown that the use of ceramic fillers or metallic components (e.g., aluminum hydroxide) is particularly well-suited to transporting a large amount of heat into the surrounding system despite a reduced diameter. When this is brought into contact with a system with high heat distribution, efficient heat propagation can be achieved within the support plane of the electric surface heating system.

[0040] According to another embodiment, the self-limiting heating cable has an electrically conductive layer (shielding layer). This layer is insulated, in particular, by an additional outer sheath (e.g., a known electrically insulating material). Furthermore, the electrically conductive layer includes a protective conductor. This can have the advantage of simultaneously improving elasticity and providing electrical protection.

[0041] In one embodiment, a self-limiting heating cable is provided with an outer shielding layer that can be connected to the system earth, thus allowing a rapid system shutdown via a residual current device (RCD) in the event of cable perforation (e.g., by nails or drill bits). A suitably designed conductive sheath can, in addition to its safety function, also provide further control of elasticity (or, depending on the cable design, homogenization of elasticity), thereby further reducing bulging. In one example, the shielding layer is finely woven, similar to a round, shielded ribbon cable. In another exemplary embodiment, the shielding layer is a tinned copper braid, and in yet another, it is an aluminum foil with a tinned copper protective conductor.

[0042] According to another embodiment, the self-limiting heating cable is configured to provide a change in its bending properties when the temperature increases (particularly to 30°C or more, and further specifically to 50°C or more). This has the advantage that the bendability (flexibility) of the self-limiting heating cable can be further increased.

[0043] In another embodiment, the self-limiting heating cable is heated for bending. By using plastics that allow for easier deformation at higher temperatures (without loss of cable geometry), it may also be possible to support the warp-free bending process.

[0044] According to another embodiment, the self-limiting heating cable is designed as a round cable. This has the advantage that a self-limiting heating cable is provided which exhibits particularly favorable bending properties in all spatial directions and can therefore be installed flexibly.

[0045] According to the invention, the self-limiting heating cable comprises: i) a first conductor and a second conductor, each having a first resistance, wherein the first and second conductors are arranged (essentially) parallel to each other in the self-limiting heating cable, and ii) a self-limiting material arranged between the first and second conductors, which has a second resistance that is higher than the first resistance and is temperature-coupled. This can have the advantage that a known self-limiting heating cable concept, with appropriate height adjustment, can be directly implemented.

[0046] According to another embodiment, the self-limiting material is configured such that the second resistance increases with rising temperature of the self-limiting heating cable due to temperature coupling, thereby defining a self-limiting maximum temperature. This has the advantage of providing a particularly safe and reliable electric surface heating system.

[0047] In an alternative according to the invention, the first and / or the second longitudinal conductor has a first extension in the lateral direction (y) and a second extension in the vertical direction (z), wherein the first extension is different from the second extension, and the second extension is larger than the first extension. This allows the self-limiting heating cable to be height-adjusted with the desired bending property.

[0048] In one example, the low-resistance conductor has a vertical extent larger than, or significantly larger than, its horizontal extent. This allows the self-limiting heating cable to be provided in a shape that is at least approximately round.

[0049] In a further alternative according to the invention, the self-limiting material, viewed in a cross-section of the self-limiting heating cable, is (essentially) circular in shape. This allows the self-limiting heating cable to be height-adjusted with the desired bending properties.

[0050] In one example, the self-limiting heating cable is constructed coaxially. This involves an inner core made of insulating material, with a conductor positioned above and below the core. The circular space between the conductors is then filled with self-limiting material (and, in particular, an outer insulation layer is added).

[0051] In another embodiment of the invention, the self-limiting material is bent. In particular, the self-limiting material is loop-shaped. Furthermore, and especially, additional insulating material is arranged within the loop shape. This makes it possible to adjust the height of the self-limiting heating cable with the desired bending properties.

[0052] In one example, the self-limiting material is reshaped, e.g., to approximate a round cable and / or meandering, (micro-)loop formation, etc.

[0053] For example, the following procedure can be used: A self-limiting heating cable is designed using a planar approach analogous to the state of the art, possibly even wider than previously common, and provided with outer insulation. During further cable manufacturing, loops can be formed with additional insulation (or insulating material) inserted during production. The insulating material can be identical to the existing insulating material of the self-limiting material. This insertion can be a form of deformation and can take place, in particular, at a point when the self-limiting material is easily deformable.

[0054] In this particular design, the self-limiting heating cable can be in a spiral shape, which only needs to be opened a certain amount during installation. This is especially advantageous because, with this design, the inner end of the spiral does not need to be connected anywhere, and the spiral can be energized at its outer connection.

[0055] According to a further embodiment, the extent of the self-limiting material between the first and second conductors (as seen in a cross-section of the self-limiting heating cable) is greater than the distance between the first and second conductors. In a further alternative according to the invention, the self-limiting material (as seen in a cross-section of the self-limiting heating cable) is arranged between the first and second conductors in a substantially wave-like or C-shaped (more specifically, at least approximately circular) form. This allows the self-limiting heating cable to be height-adjusted with the desired bending properties.

[0056] One embodiment provides further folds of the self-limiting heating cable, such as a C-shaped or crescent-shaped design (a double layer of length conductors running as centrally as possible, which figuratively corresponds to an almost closed crescent moon).

[0057] According to a further embodiment, the electric surface heating system also comprises: i) a heating area in which the curved section of the self-limiting heating cable is arranged, and ii) a free area in which the curved section of the self-limiting heating cable is not arranged. This can have the advantage that free zones are provided which allow for subsequent processing, in particular drilling.

[0058] In one embodiment, a clear area can be detected via (additional registration points), which makes it possible to determine the position of these clear zones without direct line of sight to the heating system. This registration mechanism (e.g., via area markers) can allow for safe penetrations even after installation, when the system is completely covered with building materials. With such an electric surface heating system, it is possible to distinguish (pre-planned) clear areas from sensitive heating zones containing live heating components after installation in a building. This can allow for flexible and safe subsequent mounting of objects on floors, walls, and ceilings (e.g., by drilling) during later modifications and extensions.

[0059] In one embodiment, at least one of the self-limiting and one of the unlimited heating elements are implemented using heating foils. This raises the issue of the subsequent perforation of this assembly. Since heating systems are typically implemented over large areas, this problem can be exacerbated. A solution can be achieved by creating regular cutouts in the heating foil and its connecting elements. By using individual registration points, whose position can be detected through a finished surface structure (e.g., magnetically, capacitively, inductively, etc.), it is possible to determine the locations of these cutouts and drill holes (for wall boxes, fittings, base profiles of lightweight walls, etc.) at suitable locations without damaging the heating system.

[0060] Within the context of this document, the term "heating area" may refer specifically to an area within an electric radiant heating system that contains an electric heating component and is therefore unsuitable for modification (especially drilling). In one example of a heating area, a heating cable is embedded in the support structure of the electric radiant heating system. Within this heating area, the likelihood of damaging (or penetrating) the heating component (e.g., the heating cable, heating film) and / or its insulation when drilling through non-transparent covering material and the underlying heating area (e.g., through the support structure of the electric radiant heating system) is significantly increased. This likelihood may be so high that a specialist would advise against drilling because the risk of damage is too great.In this example, the term "heating zone" refers not only to the heating component itself, but also to the surrounding area where machining or drilling would generally be prohibited due to safety concerns. In this example, the heating zone of an electric surface heating system is defined and documented. Furthermore, the heating zone can be associated with the positions of zone markers.

[0061] Within the context of this document, the term "free zone" can refer specifically to an area within an electric surface heating system that does not contain an electrical heating component and is therefore suitable for machining (especially drilling). In one example of a free zone, no heating cable is embedded in a section of the electric surface heating system's support structure. In another example, a heating film has free zones without a heating function. In yet another example, sections of heating film are used as heating zones, with free zones left between them. The free zone can be large enough to allow safe drilling through non-transparent covering material and the underlying free zone. The size of the free zone can be chosen such that the probability of missing it during drilling becomes negligible.

[0062] According to a further embodiment, the electric surface heating system further comprises: i) a first surface heating module, ii) a second surface heating module, and iii) a connector (or a connecting element) which connects the first surface heating module and the second surface heating module, in particular wherein at least one of the surface heating modules is 10 dm² or larger, in particular 25 dm² or larger, and further in particular 50 dm² or larger. This has the advantage that an electric surface heating system can be designed flexibly and with advantageous additional functionalities.

[0063] In one embodiment, an electric surface heating system consists of individual heating modules that can be connected to each other using connecting elements. The described connecting elements ensure the correct positioning during connection, and in this case, the connectors can already be part of the next module.

[0064] In one example, a surface heating module can have additional functionalities integrated, such as insulation (especially foam-based) towards the floor, wall, or ceiling. This additional thickness creates a certain degree of flexural rigidity, which, due to the resulting panels, facilitates installation. In another example, a tongue-and-groove mechanism, particularly in the insulation area, can contribute to the increased positioning stability of a modular system. The modules can be laid out and connected to one another. The modules can incorporate other building materials, such as insulation, impact resistance protection (during construction), or load-bearing / assembly aids. In another example, prefabricated installation modules (especially those with polystyrene insulation on the underside) can be connected using the connecting elements.

[0065] According to a further embodiment, the electric surface heating system further comprises: at least two temperature-limiting zones, in particular wherein at least one of the temperature-limiting zones is 25 dm²< , in particular 10 dm²< , further in particular 2 dm²< , or smaller.

[0066] In one example, zones (for self-regulation) with a limited area are provided, most of which are equipped with a temperature limiting mechanism. Good results were achieved when such zones are smaller than 25 dm², preferably smaller than 10 dm², and particularly preferably smaller than 2 dm².

[0067] These square decimeter dimensions can be used for the intended individually controlled temperature-limiting zones, for example, as a replacement for self-limiting heating elements. Energy-related reduction and / or shutdown can be implemented, for example, using thermostats as temperature-limiting zone elements. These thermostats reduce or shut off the power supply to heat a (locally) nearby area (or temperature-limiting zone) at a certain temperature threshold, particularly for zones smaller than 25 dm². In one example, the zones are defined by a grid structure of heating elements, with temperature-limiting zone elements being arranged along the heating elements.

[0068] According to a further embodiment, the diameter of the self-limiting heating cable in the vertical direction (z) is equal to or less than the diameter in a horizontal direction (y), which is defined by the substantially parallel longitudinal conductors. According to the invention, the method further comprises: processing the self-limiting heating cable (in particular, the self-limiting material of the self-limiting heating cable). Specifically, processing such that the self-limiting material is essentially loop-shaped. Preferably, the processing includes at least one of the following: folding, rolling, and forming (especially in a not yet fully formed final state). This has the advantage that a self-limiting heating cable with the preferred bending properties or height can be mechanically manufactured from established materials.

[0069] According to a further embodiment, the method also comprises: electrically connecting a first surface heating module and a second surface heating module to each other via a connector, wherein the electrical connection is carried out by at least one of the following: insulation displacement connectors, crimping, plugging, clamping, pressing, gluing, welding, in particular ultrasonic welding or cold welding, riveting, clinching, screwing, soldering. This has the advantage that an electric surface heating system can be flexibly constructed with advantageous additional functionalities using established methods.

[0070] According to a further embodiment, the method further comprises: i) providing a self-limiting flat ribbon heating cable, ii) processing the self-limiting flat ribbon heating cable, in particular such that a self-limiting heating cable is (essentially or approximately) available as a round cable. This has the advantage that a conventional self-limiting flat ribbon heating cable can serve as the starting material for a forming process that results in a self-limiting heating cable with surprisingly advantageous properties.

[0071] In one example, the planar structure of a self-limiting heating cable is restructured in such a way that it behaves similarly when bent around the mutually perpendicular bending axes, thus preventing any relevant bulging when used in an electric surface heating system.

[0072] Exemplary embodiments of the present invention are described in detail below with reference to the following figures. Figure 1 shows a top view of an electric surface heating system according to an embodiment of the invention. Figure 2 shows a cross-section through an electric surface heating system according to an embodiment of the invention. Figures 3 to 8 Each shows a cross-section through a self-limiting heating cable according to exemplary embodiments of the invention. Figure 9 shows laying patterns of an electric surface heating system according to embodiments of the invention. Figure 10 Figure 1 shows a self-limiting heating cable according to an embodiment of the invention. Figure 11 shows a self-limiting heating cable in the form of a flat ribbon heating cable according to the state of the art. Figure 12shows an electric surface heating system with a vertically oriented, self-limiting heating cable in the form of a flat ribbon heating cable according to the state of the art.

[0073] Identical or similar components in different figures are provided with the same reference numerals.

[0074] Figure 1Figure 1 shows a top view of an electric surface heating system 100 for installation in construction according to an embodiment of the invention. The electric surface heating system comprises a self-limiting heating cable 110 and a support structure 130, which is formed along two principal directions x, y and thereby spans a support plane TE. The self-limiting heating cable 110 is arranged or embedded in the support material of the support structure 130, which is designed as a support film, in a bent (meandering) manner. The electric surface heating system 100 further comprises: a heating area 102 in which the bent self-limiting heating cable 110 is arranged, and a free area 104 in which the self-limiting heating cable 110 is not arranged. The latter serves as a clearance zone, for example, to allow for drilling when the electric surface heating system 100 is covered by a floor or wallpaper and is no longer visible.The electric surface heating system 100 has a first surface heating module 108 and a second surface heating module 109, which are connected to each other via connectors 160.

[0075] The height of the self-limiting heating cable 110 is no more than 15 mm (i.e., it is not a flat ribbon heating cable), and the self-limiting heating cable 110 nevertheless has a bending radius that is less than 30 times (in particular, less than 10 times) the largest diameter of the self-limiting heating cable 110 (viewed in cross-section, i.e., along y or z). Furthermore, the self-limiting heating cable 110 can be bent at least 180° or more in the principal directions of extension (x, y) and / or the vertical direction (z) without buckling.

[0076] Figure 2Figure 1 shows a cross-section through an electric surface heater 100 according to an embodiment of the invention. The height of the curved, self-limiting heating cable 110 in the vertical direction z, which is oriented perpendicular to the two principal extension directions x, y of the electric surface heater 100, is only 15 mm (particularly 10 mm, and more specifically 5 mm). The electric surface heater 100 can therefore be designed to be correspondingly thin. In the embodiment shown, this is made possible by the fact that the self-limiting heating cable 110 is designed as a round cable. The self-limiting heating cable 110 has a first conductor 111 and a second conductor 112, each of which has a first resistance. The first conductor 111 and the second conductor 112 are arranged parallel to each other in the self-limiting heating cable 110 and thus form a horizontal direction y.The self-limiting heating cable 110 also features a self-limiting material 115, which is arranged between the first conductor 111 and the second conductor 112, and which has a second resistance that is higher than the first resistance and is temperature-coupled. The self-limiting material 115 is configured such that the second resistance increases with increasing temperature of the self-limiting heating cable 110 due to temperature coupling, thereby defining a self-limiting maximum temperature.

[0077] The Figures 3 to 8 Each figure shows a cross-section through a self-limiting heating cable according to exemplary embodiments of the invention. Although these are depicted as round cables in the figures, they can also be implemented with other cross-sectional shapes. For clarity, additional electrically insulating or electrically conductive layers have not been shown.

[0078] Figure 3 : The first and second longitudinal conductors 111, 112 have a first extension in the lateral direction y and a second extension in the vertical direction z. The second extension is larger than the first. Because the longitudinal conductors are "stretched upwards," a height-adapted, self-limiting heating cable 110 can be provided.

[0079] Figure 4 : The self-limiting material 115 is shaped such that it is bent. The self-limiting material 115 is loop-shaped, with insulating material 121 inserted within the loops. The insulating material 121 can correspond to the electrically insulating material 116, which is arranged around the self-limiting material (not shown).

[0080] Figure 5 : similar Figure 4, but the loop shape is even more pronounced and more insulating material 121 is used.

[0081] Figure 6 : The self-limiting material 115 is essentially circular in shape between the length conductors 111, 112.

[0082] Figure 7 : The extent of the self-limiting material 115 between the first length conductor 111 and the second length conductor 112 is greater than the distance between the first length conductor 111 and the second length conductor 112. The self-limiting material is arranged in a substantially C-shape between the first length conductor 111 and the second length conductor 112.

[0083] Figure 8 : similar Figure 7 , but the self-limiting material 115 is essentially formed in the shape of a crescent moon (or an almost closed circle) between the length conductors 111, 112.

[0084] Figure 9Figure 1 shows the installation pattern of an electric surface heating system 100 according to embodiments of the invention. Although a self-limiting heating cable 100 is used, the installed electric surface heating system 100 is no more than 15 mm high.

[0085] Figure 9a : electric surface heating 100 with support structure 130 and curved self-limiting heating cable 110 embedded therein upon delivery.

[0086] Figure 9b : For installation in the construction area, the support structure 130 is cut and the self-limiting heating cable 110 can be bent.

[0087] Figure 9c : the self-limiting heating cable 110 is bent by 180° to allow for re-routing.

[0088] Figure 9d : the self-limiting heating cable 110 is bent by 90° to allow for a corner recess.

[0089] Figure 9eThe self-limiting heating cable 110 is bent several times by 180° to allow a large area with a single-sided connection.

[0090] Figure 10Figure 1 shows a detailed view of a self-limiting heating cable 110 according to an embodiment of the invention. The self-limiting material 115 embeds the conductors 111, 112 and is positioned between them. An electrically insulating layer 116 is applied around the self-limiting material 115. This layer can, for example, be an electrically insulating material with high thermal conductivity, such as a ceramic material like aluminum hydroxide. An electrically conductive layer 117, such as a copper-tinned protective braid or an aluminum protective foil, is applied around the electrically insulating layer 116. This electrically conductive layer 117 preferably includes a protective conductor. Finally, the electrically conductive layer 117 is enclosed by an outer sheath 118 (in particular, an electrically insulating one).

[0091] It should also be noted that "having" does not exclude any other elements or steps, and "a" or "an" does not exclude a plurality. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference numerals in the claims are not to be considered as limitations. Reference sign

[0092] 100 Electric surface heating 102 Heating area 104 Free area 108 First surface heating module 109 Second surface heating module 110 Self-limiting heating cable 111 First conductor 112 Second conductor 115 Self-limiting material 116 Electrically insulating layer 117 Electrically conductive layer 118 Outer sheath 121 Insulating material 130 Support structure 160 Connector, connecting element TE Beam plane x Longitudinal direction y Latitude direction z Height direction State of the art

[0093] 200 Electric surface heating 210 Self-limiting heating cable 211, 212 Longitudinal conductor 215 Self-limiting material

Claims

1. A self-limiting heating cable (110) for an electric panel heater (100), which comprises: a first longitudinal conductor (111) and a second longitudinal conductor (112), which each have a first resistance, wherein the first longitudinal conductor (111) and the second longitudinal conductor (112) are arranged substantially parallel next to one another in the self-limiting heating cable (110); and a self-limiting material (115), which is arranged between the first longitudinal conductor (111) and the second longitudinal conductor (112), and which comprises a second resistance, which is higher than the first resistance, and which is temperature-coupled; wherein the self-limiting heating cable (110) comprises at least in sections a bending radius, which is 30 times, in particular 20 times, further in particular 10 times, or less the largest diameter of the self-limiting heating cable (110), seen in cross-section; and / or wherein the self-limiting heating cable (110) is bendable at least in sections by 90°, in particular 180°, or more in two spatial directions oriented perpendicularly to one another, in particular without substantial bulging; wherein the self-limiting heating cable (110) further comprises at least one of the following features: wherein the first and / or the second longitudinal conductor (111, 112) comprises a first extension in the width direction (y) and comprises a second extension in the height direction (z), wherein the first extension is different from the second extension, wherein the second extension is larger than the first extension; wherein the self-limiting material (115), seen in a cross-section of the self-limiting heating cable (110), is formed substantially circularly between the first longitudinal conductor (111) and the second longitudinal conductor (112); wherein the self-limiting material (115), seen in a cross-section of the self-limiting heating cable (110), is loop-shaped with insulating material (121) within the loops; wherein the self-limiting material (115), seen in a cross-section of the self-limiting heating cable (110), is arranged substantially wave-shaped or C-shaped between the first longitudinal conductor (111) and the second longitudinal conductor (112).

2. An electric panel heater (100) for laying in the construction sector, wherein the electric panel heater (100) comprises: a self-limiting heating cable (110) according to claim 1; and a support structure (130), which is formed along two main extension directions (x, y) and spans a support plane (TE); wherein at least one section of the self-limiting heating cable (110) is arranged in a bent manner at and / or in the support structure (130), wherein the height of the bent section of the self-limiting heating cable (110) in a height direction (z), which is oriented perpendicularly to the two main extension directions (x, y), is 15 mm or less.

3. The electric panel heater (100) according to claim 2, wherein the height of the bent section of the self-limiting heating cable (110) is 10 mm or less, further in particular 8 mm or less, further in particular 5 mm or less.

4. The electric panel heater (100) according to claim 2 or 3, wherein the self-limiting heating cable (110) comprises at least in sections a bending radius, which is 30 times, in particular 20 times, further in particular 10 times, or less the largest diameter of the self-limiting heating cable (110), seen in cross-section.

5. The electric panel heater (100) according to one of the preceding claims 2 to 4, wherein the self-limiting heating cable (110) is bendable at least in sections by 90°, in particular 180°, or more in the main extension directions (x, y) and / or the height direction (z), in particular without substantial bulging.

6. The electric panel heater (100) according to one of the preceding claims 2 to 5, wherein the self-limiting heating cable (110) comprises: a first region, which is configured in particular for heating, and comprises a first bending property; and a second region, which is configured in particular not for heating, and comprises a second bending property; wherein the first bending property and the second bending property are different from one another, in particular wherein the second bending property comprises a higher elasticity than the first bending property.

7. The electric panel heater (100) according to one of the preceding claims 2 to 6, wherein the electric panel heater (100) comprises at least one of the following features: wherein the self-limiting heating cable (110) comprises a waterproof, in particular immersion-proof, insulating layer; wherein the self-limiting heating cable (110) comprises an electrically insulating layer (116), which comprises an electrically insulating material with high thermal conductivity, in particular a ceramic material, further in particular aluminum hydroxide; wherein the self-limiting heating cable (110) comprises an electrically conductive layer (117), in particular which is insulated with an outer jacket (118).

8. The electric panel heater (100) according to one of the preceding claims 2 to 7, wherein the self-limiting heating cable (110) is configured to provide a change in a bending property upon a temperature increase, in particular to 30°C or more, further in particular to 50°C or more.

9. The electric panel heater (100) according to one of the preceding claims 2 to 8, wherein the self-limiting heating cable (110) is configured as a round cable.

10. The electric panel heater (100) according to one of the preceding claims 2 to 9, wherein the self-limiting material (115) is configured such that the second resistance increases with increasing temperature of the self-limiting heating cable (110) due to the temperature coupling, and such that a self-limited maximum temperature is thereby pregiven.

11. The electric panel heater (100) according to one of the preceding claims 2 to 10, wherein the extension of the self-limiting material (115) between the first longitudinal conductor (111) and the second longitudinal conductor (112), seen in a cross-section of the self-limiting heating cable (110), is larger than the distance between the first longitudinal conductor (111) and the second longitudinal conductor (112).

12. The electric panel heater (100) according to one of the preceding claims 2 to 11, wherein the electric panel heater (100) comprises at least one of the following features: wherein the electric panel heater (100) further comprises: a heating region (102), in which the bent section of the self-limiting heating cable (110) is arranged; and a free region (104), in which the bent section of the self-limiting heating cable (110) is not arranged; wherein the electric panel heater (100) further comprises: a first panel heating module (108); a second panel heating module (109); and a connector (160), which connects the first panel heating module (108) and the second panel heating module (109) to each other.

13. A method for manufacturing a self-limiting heating cable (110) according to claim 1 for an electric panel heater (100), the method comprising: arranging two longitudinal conductors (111, 112), which each have a first resistance, substantially parallel next to one another; providing a self-limiting material (115) between the first longitudinal conductor (111) and the second longitudinal conductor (112), which comprises a second resistance, which is temperature-coupled, and which is higher than the first resistance, such that the self-limiting heating cable (110) comprises at least in sections a bending radius, which is 30 times, in particular 20 times, further in particular 10 times, or less the largest diameter of the self-limiting heating cable (110), seen in cross-section; and / or the self-limiting heating cable (110) is bendable at least in sections by 90°, in particular 180°, or more in two spatial directions oriented perpendicularly to one another, in particular without bulging; wherein the method further comprises: providing a self-limiting flat ribbon heating cable (210); processing the self-limiting flat ribbon heating cable (210) such that a self-limiting heating cable (110) is substantially a round cable.

14. A method for manufacturing an electric panel heater (100) for the construction sector, wherein the method comprises: manufacturing a self-limiting heating cable (110) according to claim 13 and providing this self-limiting heating cable (110); providing a support structure (130), which is formed along two main extension directions (x, y) and spans a support plane (TE); bending at least one section of the self-limiting heating cable (110); and arranging at least the bent section of the self-limiting heating cable (110) at and / or in the support structure (130); wherein the height of the bent section of the self-limiting heating cable (110) in a height direction (z), which is oriented perpendicularly to the two main extension directions (x, y), is 15 mm or less, and wherein the method further comprises: processing, in particular by means of one from the group consisting of: folding, rolling, forming, self-limiting material (115) of the self-limiting heating cable (110) such that the self-limiting material (115) is at least one from the group consisting of: substantially circular, substantially loop-shaped, wave-shaped, C-shaped.

15. The method according to claim 14, further comprising: electrically connecting a first panel heating module (108) and a second panel heating module (109) to each other via a connector (160), wherein the electrical connecting is carried out by at least one from the group consisting of: cutting clamping, crimping, plugging, clamping, pressing, gluing, welding, in particular ultrasonic welding or cold welding, riveting, clinching, screwing, soldering.