EP4111819A1

EP4111819A1 - Heating device

Info

Publication number: EP4111819A1
Application number: EP21702902.4A
Authority: EP
Inventors: Matthias Mandl; Michael Tafferner; Thomas Hauk; Manuel Schmieder; Holger Koebrich; Roland Mühlnikel; Alfred Suss; Sebastian Eigl; Henry ZIPPLIES; Volker Block
Original assignee: EGO Elektro Geratebau GmbH
Current assignee: EGO Elektro Geratebau GmbH
Priority date: 2020-02-26
Filing date: 2021-01-27
Publication date: 2023-01-04
Also published as: JP2023516170A; KR20220147085A; US20220386420A1; WO2021170331A1; WO2021170232A1; CN115136733A

Abstract

The invention relates to a heating device having a flat expanded support and at least one heating conductor assembly thereon which is electrically connected by means of two connection contacts. The heating conductor assembly has a plurality of heating conductors which are connected together at connection points and are wired as a whole so as to form parallel and series circuits between the connection contacts. The plurality of heating conductors are advantageously designed as a lattice, wherein every set of four heating conductors forms a closed mesh, and four heating conductors are connected together at the connection points. The heating conductor assembly is applied onto the support with a film construction in a film method, advantageously a thick-film method.

Description

Heating device

AREA OF APPLICATION AND STATE OF THE ART

The invention relates to a heating device with a carrier, connection contacts and at least one heating conductor arrangement on the carrier with a plurality of heating conductors.

From EP 3145273 A1 a heating device is known with a carrier, on the outside of which heating conductors are attached. The carrier can be flat or tubular. The heating conductors then run in a meander shape or in loops with parallel paths. The individual tracks as heating conductors are connected in series, i.e. in series, and connected to the connection contacts. The design options are limited by simply connecting the heating conductors in series. Between 65% and 80% of the surface of the carrier are covered with the heating conductors, which enables a very high surface density of the heating output.

From DE 102016225462 A1 a heating device is known in which a grid or network of heating conductors runs freely between connection contacts that hold the heating conductor arrangement. As a result of heat dissipation, in particular to the ambient air, is very possible. The disadvantage here is that a carrier, for example as a container wall or as a pipe wall, in order to heat the water located therein, can be heated poorly or inefficiently with it.

TASK AND SOLUTION

The invention is based on the object of creating a heating device mentioned at the beginning with which problems of the prior art can be solved and in particular it is possible to design a heating device with a flat carrier and at least one heating conductor arrangement thereon simply and at the same time in a basically variable manner, as well as an area output to be able to influence on the one hand the most homogeneous area performance possible and on the other hand areas of higher or lower area performance.

This object is achieved by a heating device with the features of claim 1. Advantageous and preferred embodiments of the invention are the subject matter of the further claims and are explained in more detail below. The wording of the claims is made part of the content of the description by express reference.

It is provided that the heating device has a support that extends over a flat area. The water can on the one hand be flat and level, on the other hand it can be curved or as a channel, Tub or be designed as a pipe. The heating device has at least two connection contacts and at least one heating conductor arrangement, which are each angeord net on the carrier. The heating conductor arrangement is connected to the at least two connection contacts in order to be electrically connected. The entire heating device can also have more than two connection contacts, for example for divided or distributed subsets of heating conductors. As a result, different heating can be achieved in a heating device either in terms of area or in terms of performance.

The at least one heating conductor arrangement has a multiplicity of heating conductors, for example more than fifty heating conductors or several hundred heating conductors. These heating conductors are connected to one another at connection points so that they meet at the connection points. They are connected to the connection points in an electrically conductive manner and are thus also connected to one another in an electrically conductive manner. Overall, the heating conductors are connected in parallel and in series between the connection contacts. Advantageously, the heating conductors form a network with the connection points as nodes, in particular branched out in multiple ways and brought together again, so that an exact subdivision or differentiation into parallel connection and series connection is not possible. The heating conductor arrangement has a multiplicity of meshes which are formed by at least three heating conductors, so that the meshes are closed, at least most of them. At the connection points that are encompassed by this mesh, at least three heating conductors are connected to one another or meet. The heating conductor arrangement is advantageously applied to the carrier in a layer process with a layer structure. A thick-film process is available for this, alternatively a thin-film process, plasma spraying, CVD and PVD processes. The heating conductors of the entire heating conductor arrangement are preferably produced together, that is to say together in one step or together in several steps for the layer structure.

The formation of the heating conductor arrangement with the large number of individual heating conductors, which are constructed in a kind of network or grid, so that they are all flowed through by current, enables a well-distributed arrangement of the individual heating conductors. Less than 60%, advantageously less than 50% or even less than 40% of the area of the carrier in the area of the heating device can be covered directly, but at the same time the area of the carrier in this area can be covered approximately evenly with the heating conductors. This he makes it possible to heat the carrier very evenly or with a homogeneous area output seen over the surface, but overall with lower output than in the prior art. The area output is therefore advantageously related to the area of a heating conductor arrangement or to the area which is continuously covered by heating conductors or heating conductor arrangements. In an embodiment of the invention, a direction of the heating conductors can have an angle with a longitudinal extension of the connection contacts, this angle being in a range between 2 ° and 85 °. Thus, the heating conductors run neither parallel nor at right angles to one of the connection contacts, but at an angle in between or at an angle to it. The angle can advantageously be between 35 ° and 60 °, particularly advantageously it can be around 45 °. In this way, a uniform structure of the heating conductor arrangement can be achieved.

It is advantageously provided that the heating conductors each run straight, in particular all heating conductors of the heating conductor arrangement run straight. So problems with Stromkonzen trations or the like. as they can occur on curved heating conductors, do not even emerge. It can be provided that there are only exactly two or exactly three course directions in total for the heating conductors, and each of the heating conductors then runs along one of these course directions.

In an embodiment of the invention, at least 80% of the connection points can have the same number of heating conductors connected to them; these are particularly advantageously at least 95% of the connection points. This means that in some exceptions, in particular at an edge area of the heating conductor arrangement or the number of heating conductors on the carrier, it may be that fewer or more heating conductors are provided or meet at a connection point. In the edge areas of the heating conductor arrangement, this will be difficult to avoid, here, as a rule, fewer heating conductors will be provided at a connection point. There are no heating conductors that would run into the free area next to the edge area.

In a further embodiment of the invention it can be provided that at 95% of the connection points or at most exactly three heating conductors or exactly four heating conductors meet. A more homogeneous configuration of the heating conductor arrangement is also possible in this way. If three heating conductors meet at a connection point, the associated meshes can be hexagonal or advantageously triangular, in particular regularly in each case. If four heating conductors meet at a connection point, the associated meshes can advantageously be square or square.

Alternatively, the meshes can be approximately hexagonal or in the form of a honeycomb, preferably precisely hexagonal. In this case, four longitudinal sides of the hexagon can each be formed by a single heating conductor, while two opposite longitudinal sides of the hexagon are each formed by an elongated connection point. This connection point is then a kind of elongated connection area, preferably the Heating conductors are longer than the elongated connection points, in particular 50% to 300% longer.

In an advantageous development of the invention, most heating conductors run straight, in particular at least 80% or even at least 95%. By designing most or all of the heating conductors straight, the problems described above with inhomogeneous current conduction along curved paths can be avoided, which either lead to an undesirably homogeneous heating power distribution or damage to the heating conductor and / or to the carrier.

In an alternative embodiment of the invention, most heating conductors are curved, in particular at least 80% of the heating conductors are curved. The heating conductors are advantageously designed to be curved twice in opposite directions, in particular S-shaped. The two opposing arcs are particularly advantageously evenly curved. Such a design can be point-symmetrical to a point on half the length of the heating conductor. It can thereby be achieved that a length of a curved heating conductor, in particular curved once, twice or several times, between the connection points at its ends with the other heating conductors is at least 5% greater than the direct straight extension between these connection points. A length can preferably be even greater, in particular at least 10% greater, for example at least 20% greater.

A curved heating conductor makes it possible, on the one hand, to achieve a higher resistance value for a heating conductor material with an advantageous thickness and width of the conductors due to the increased length for a given resistance. On the other hand, a better distribution of the course of the heating conductors and thus also of their generated heating power or heat can take place over the area covered overall by the heating conductor arrangement. The heating conductors can always be curved or do not run straight in any section. Alternatively, they could run straight in a section, for example a central section, where there is a change in curvature.

In an advantageous development of the invention, a large number of the heating conductors have the same length, in particular at least 80% of the heating conductors. Advantageously, at least 95% of the heating conductors have the same length, so that actually only a few heating conductors differ in terms of their length, for example because they are arranged on the edge area of the heating conductors or are adjacent to open space areas, as will be explained in detail below as an option . It can preferably be provided that the majority of the heating conductors have the same shape. This can be at least 80% of the heating conductors, particularly advantageously at least 95% of the heating conductors. These are therefore identical in terms of length, width, length and thickness. If a homogeneous power supply is then provided by appropriate construction of the heating conductor arrangement, a homogeneous heating output also takes place.

In an embodiment of the invention, an angular area between two adjacent heating conductors that meet or are connected to one another at a connection point can not be angular or pointed, but rounded. A rounding in this angular range can be such that it is rounded with a radius of at least 2% of the maximum width of one of the heating conductors. In particular, this radius can be 5% to 100% or even up to 200% of the maximum width of a heating conductor, preferably 20% to 50%. Then there are no discontinuous inhomogeneities in the current distribution in this angular range. Due to the rounding, the conductor cross-section is enlarged somewhat due to the larger width, which leads to a reduction in the heating output. However, this can be limited by the design of the radius so that it does not have a disruptive effect. Under certain circumstances, such a rounding can also simplify the manufacture of the heating conductor arrangement, for example in the case of screen printing.

Provision can be made for such a rounding to be provided in the angular area in at least 80% or in at least 95% of the connection points, preferably in all angular areas at the connection points. A rounding can in particular also be designed identically, so that the same design and the same behavior are achieved in heating mode.

In a first embodiment of the invention, it is possible that a connection point is formed in that heating conductors each having the same width cross one another, in particular two heating conductors, each of these heating conductors being able to have a constant width. The area that is covered, so to speak, by the longitudinal course of the two heating conductors is then the connection point. A connection point can also be created in a similar form if not four, but only three heating conductors are connected to one another on it. These then do not have to run beyond the connection point.

In a second embodiment of the invention, a connection point can be an area which is larger than a pure crossover region in accordance with the aforementioned first embodiment of the invention, as has been described above. This can ensure that the same current density prevails in the area of the connection point as in the heating conductors itself, so that a heating power generation at the connection point is the same or at least not stronger than in the heating conductors themselves. This can possibly also be achieved by not making the area of a connection point larger, but rather the layer thickness.

In a further embodiment of the invention, it is possible that different widths are provided for the heating conductors, preferably with a variation of the width of a maximum of 40%. A variation in the width of the heating conductors should advantageously be a maximum of 25%. If the heating conductors all have the same layer thickness, a different generation of heating power can take place locally or in areas. If the heating conductors are of the same length, the narrower heating conductors generate more heating power than the wider heating conductors. Thus, the heating power or heating can be varied locally or in areas with the heating device.

It can advantageously be provided that a heating conductor has a constant width over an extension between the two connection points at its ends or over its length. Thus, the power generation at least at this heating conductor is distributed equally over its length.

Alternatively, it can be provided that a heating conductor has a width which, viewed over its length, or over an extension between the two connection points at its ends, varies. A variation should be in the aforementioned range of a maximum of 40% or even a maximum of 25%. Otherwise, it could be that the difference in the generation of the heating power becomes too great with the risk of damage to the heating conductor or to the heating device due to excessively high temperatures with an uneven temperature distribution.

The width of the heating conductor can preferably increase monotonically from one connection point to the other connection point, or alternatively decrease monotonically. The width particularly preferably increases or decreases in a strictly monotonous manner.

In a further development of the invention it can be provided that a layer thickness of the heating conductor arrangement or the heating conductor itself varies by a maximum of 20% or 10%, that is not too different. It advantageously only varies by a maximum of 2% or is the same everywhere and is produced at least by the production method with the same nominal thickness. Then the heating conductor arrangement can be produced by a layer structure, for example by means of a thick film process, in that all the material for the heating conductor is always applied simultaneously in one step or in several steps with the same amount or with the same layer thickness. This enables a simple and practical manufacturing process. In a further embodiment of the invention it can be provided that a plurality of said connection points have only two heating conductors in at least one area of the heating conductor arrangement or, so to speak, only two heating conductors meet there. These heating conductors then preferably do not run in a straight line, but rather have an angle to one another, for example in the range of the aforementioned 35 ° to 60 °. As such, these heating conductors advantageously correspond to the other heating conductors in terms of width and / or length, advantageously also thickness. These connection points with only two heating conductors are particularly advantageously in an edge area of the heating conductor arrangement or can adjoin a free surface area within the heating conductor arrangement. It can thus be achieved that, on the one hand, the arrangement of the heating conductors is the same as elsewhere or in the predominant area of the heating conductor arrangement, in particular regularly designed. A named free surface area of the heating conductor arrangement can, so to speak, be surrounded by heating conductors and, for example, serve to provide electrical connections or sensors, for example temperature sensors, through an unheated area, that is to say in which no heating conductors are provided here. These should advantageously not be heated too much or be exposed too much to the heating effect of the heating conductors. A named edge area can cleverly also be present towards such a free surface area. A free surface area can generally vary in size, advantageously it has an area between four times and one hundred times the area of a mesh, particularly advantageously between ten and forty times. A free surface area is advantageously delimited or completely framed by heating conductors or by the heating conductor arrangement.

In a further embodiment of the invention, it is possible that a cutout is provided in an edge region of the heating conductor arrangement, that is to say on the side, so to speak. Such a cutout can be designed in the manner of an indentation, two or three heating conductors being connected to one another in the area of this indentation at the adjacent or external connection points. Exactly one heating conductor is advantageous here, or precisely two heating conductors are less connected to one another than at the majority of the connection points of the other heating conductor arrangement. Thus, so to speak, those heating conductors are missing which otherwise run into or would protrude into the area of the indentation mentioned.

A named free surface area within the heating conductor arrangement is preferably designed in such a way that it is free of heating conductors and also of connection points. The free surface area should be framed by heating conductors, in particular in accordance with the other regular arrangement of heating conductors in the predominant area of the heating conductor arrangement. Depending on the design of the meshes or the arrangement of the heating conductors meeting at the connection points, it can be provided that the free surface area of heating conductors is Rader extension or extension to each other is framed. It is also possible for two or three heating conductors, preferably three, to be connected to one another at several connection points that adjoin the free surface area.

In an advantageous embodiment of the invention it can be provided that a surface heating capacity varies by a maximum of 25% within the surface of the heating conductor arrangement, in particular only where the heating conductors run, i.e. without the aforementioned free surface areas. In particular, the surface heating output can only vary by a maximum of 10%. The most homogeneous possible heating power generation with the heating device can be advantageous. Alternatively, a variation of the surface heating output can also be used within a heating conductor arrangement to specifically provide higher heating outputs in certain areas. Precisely because of the aforementioned variation in the width of the heating conductors, this is also easily possible within a single heating conductor arrangement, in particular also with a continuous change in the surface heating output. As a result, changes in the heating output that are too different, which could possibly lead to damage, can be avoided.

In a further embodiment of the invention, auxiliary connection contacts can be provided which are connected to each of the connection contacts. Such secondary connection contacts can lie opposite one another in pairs in a direction perpendicular to a longitudinal course of the connection contacts. They can run parallel to the connection contacts, so to speak, if these are straight, which they are advantageously. Each auxiliary connection contact is connected to a connection contact directly or via a further auxiliary connection contact. They can be electrically connected to each other and to the connection contact by means of bridge contacts. The secondary connection contacts are advantageously made of the same material as the connection contacts, particularly advantageously also with the same width and thickness. For example, they can be produced together. The bridge contacts should then be made somewhat different or made of a different material so that it is possible to cut them easily by lasers or mechanical scratching. In this way, the heating conductor arrangement can be electrically calibrated after manufacture in order to arrive at an exact value. Thus, certain areas of the heating conductor arrangement, that is to say some heating conductors, can possibly be separated either entirely from an electrical supply or at least partially. This depends on whether the heating conductors connected to the secondary connection contacts are only electrically contacted by these or whether they are also connected to the other heating conductors. Surface contacts can be applied to a heating conductor arrangement which are designed in the form of strips and which cover at least part of a width of a heating conductor arrangement in the direction transverse to its longitudinal extension and can make electrical contact. These surface contacts are advantageously made of a material with good electrical conductivity, for example similar to the material of the aforementioned connection contacts. The surface contacts can then be partially covered with electrically highly conductive material for electrical adjustment to a desired value of the electrical resistance, this material then overlapping and contacting an adjacent connection contact, an auxiliary connection contact or an adjacent heating conductor arrangement. This results in a kind of short circuit and thus a shortening of the heating conductor arrangement, which results in a lower electrical resistance. At least two such surface contacts can advantageously be applied next to one another with a small spacing for a comparison to different values for the resistance.

In this case, the width of such a surface contact can become larger in the direction of the adjacent connection contact, the secondary connection contact or the adjacent heating conductor arrangement, in particular at an end pointing in this direction. The surface contact can be at least 50% wider. It can thus be covered more easily and better by the electrically highly conductive material for contacting, but does not have to be so wide over its entire length. This saves material and only minimally restricts the heating function of the heating conductors covered by it. Nevertheless, the surface contact can be made well and thus contacted. In general, a surface contact can have a varying width in its longitudinal course. In particular, it can be wider from a narrow free end to the other free end, regardless of what it is adjacent to. One shape of surface contact can be a long narrow triangle.

In an advantageous embodiment of the invention, the heating device can have at least one additional heating conductor arrangement which has two additional connection contacts and a single flat additional heating conductor running between them. This flat additional heating conductor is advantageously provided with a closed surface, that is to say without interruption. The surface of the additional heating conductor is preferably rectangular. It can be provided that the additional heating conductor is elongated between the two additional connection contacts, wherein it can run perpendicular to these additional connection contacts. It should therefore be longer than it is wide in the direction of the current flow. It is advantageously at least ten times longer than it is wide, particularly advantageously at least twenty times longer. This can also apply to the heating conductor arrangement with the meshes of the heating conductor, so that they are each strip-shaped. A width of the additional heating conductor can be less than a width of the heating conductor arrangement with the distributed heating conductors. Its width can preferably be less than 50% of the width of the heating conductor arrangement, so that it is considerably narrower in its external extent. The area covered by the heating conductor material can be of a similar size, but it is also advantageously smaller.

A length of the additional heating conductor can be between 90% and 150% of the length of the heating conductor arrangement. They are particularly advantageously of a similar length, so that the additional heating conductor can have a length between 100% and 120% of the length of the heating conductor arrangement.

Overall, it is possible for the heating device to have at least one or two heating conductor arrangements according to the invention and at least two additional heating conductors described above. The surface output is different in each case; in particular, the heating conductor arrangements according to the invention can have a varying surface heating output. This is advantageously not possible with the additional heating conductors due to their continuous flat design. One or two heating conductor arrangements and two additional heating conductors can each run parallel to one another, the additional heating conductors having the heating conductor arrangements according to the invention between them. However, a plurality of additional heating conductors can also be provided in parallel with a single heating conductor arrangement according to the invention, the additional heating conductors advantageously having the heating conductor arrangement between them.

In an embodiment of the invention, an insulation layer and / or a dielectric layer can be provided under the heating conductor or between the heating conductor and the carrier. This layer is at least as wide as the heating conductor and a maximum of 10 mm wider than the heating conductor on both sides of the heating conductor, so that it protrudes a maximum of 10 mm on both sides under the heating conductor, in particular a maximum of 5 mm or only 2 mm, advantageously at least 0 , Protrudes 1 mm. The course of the insulation layer or the dielectric layer can correspond to the course of the heating conductor or the heating conductor arrangement, at least in the largest area of the heating conductor arrangement. Within the mesh, the insulation layer or the dielectric layer can have free spaces in which no insulation layer or dielectric layer is provided or present. The metal surface of the carrier is exposed here.

In a further embodiment of the invention, a cover layer can be provided over or on the heating conductor, which is at least as wide as the heating conductor and a maximum of 10 mm wider than the heating conductor on both sides of the heating conductor, so that the heating conductor on both sides is a maximum of 10 mm, in particular a maximum of 5 mm or only 2 mm each. Advantageously towering they each by at least 0.1 mm on both sides. The width of the cover layer can be narrower overall than the insulation layer or the dielectric layer and thus not directly overlap the surface of the carrier. The course of the cover layer particularly advantageously corresponds to the course of the heating conductor or the heating conductor arrangement, at least in the largest area of the heating conductor arrangement. Even within these meshes, the cover layer can have free spaces in which no insulation layer or dielectric layer is provided or present. Here, in turn, the metal surface of the carrier is exposed.

While full-surface insulation is usually applied to the carrier and full-surface cover layers on the heating conductor structures for heating elements using thick-film technology in order to ensure functional basic insulation and a practical cover, the invention can save on material per se on the one hand. Due to the smaller amount of materials used for the layers of insulation and the cover as well as their behavior during cooling, on the other hand, deformation of the substrates used, regardless of their shape, is lower, in particular due to different thermal expansion coefficients. This is supported by the lattice shape in addition to the lower use of material. Layers with a smaller area simply exert less deformation forces on the substrate.

Leakage currents in this structure, especially the insulation layer or dielectric layer, are also lower. The printed area with a grid structure or grid structure or grid shape is smaller compared to a full area.

In a further embodiment, at least one of the connection contacts can be designed as a lattice structure, preferably all connection contacts which are connected to the heating conductor arrangement or heating conductors. The lattice structure of the at least one connection contact has meshes with free spaces therein. In this way, the need for contact material can be reduced.

In one embodiment of the invention, it can be provided that the heating conductor arrangement or its heating conductor are severed along free cut sections, wherein preferably individual free cut sections, which are contiguous and overall form a free cut, begin at an outer edge area of the heating conductor arrangement. So you can cut off a closed surface of the heating conductor arrangement and thereby cut through the individual heating conductors in such a way that the closed surface is electrically separated from the rest of the heating conductor arrangement and is electrically insulated. It can be provided that the free-standing Cut sections of a heating conductor at an angle between 45 ° and 90 °, preferably greater than 55 °.

In a further embodiment of the invention, additional linear tracks of heating conductor material can be provided transversely to a general current flow direction through a grid-shaped heating conductor arrangement between two connection contacts, advantageously running parallel to the connection contacts. These linear heating conductor tracks made of heating conductor material can advantageously run through connection points of the heating conductors or the meshes. They are intended to increase the safety during the operation of the heating device if, due to hotspots or so-called hot spots, local overheating occurs, which may lead to one of the heating conductors or several heating conductors being burned through or destroyed. Along these linear heating conductor tracks there are then increased Stromkon concentrations of a current flow between the two connection contacts, based on local overheating with burning through or destruction of a heating conductor at a point-like area. These current concentrations then lead to the heating conductor burning through, and along the linear heating conductor tracks this through-burning or destruction can then be continued to one side or, advantageously, to both sides, approximately parallel to the connection contacts, until the entire heating conductor arrangement between the two Connection contacts is severed. Then there is no longer any current flow between the connection contacts or through the heating conductor arrangement. This means that it is irreversibly damaged or destroyed, but at the same time it is ensured that operation with a faulty heating conductor arrangement is no longer possible. The heating device then has to be replaced or repaired, but the security against faulty operation is very high.

These and other features emerge from the claims and also from the description and the drawings, the individual features being implemented individually or in combination in the form of sub-combinations in one embodiment of the invention and in other areas and being advantageous and protectable per se Can represent versions for which protection is claimed here. The subdivision of the application into subheadings and individual sections does not limit the general validity of the statements made under these.

BRIEF DESCRIPTION OF THE DRAWINGS

1, in a first embodiment of the invention, a plan view of a heating device according to the invention with a heating conductor arrangement on a carrier, FIG. 2, in a second embodiment, a heating device similar to FIG. 1 on a tubular support,

Fig. 3 in a third embodiment, an enlargement of the heating device from Fig. 1 with Dar position of the individual heating conductors that meet at connection points and form the mesh,

FIG. 4 shows a modification of the heating device similar to FIG. 1,

Fig. 5 in a fourth embodiment, a further heating device similar to FIG. 4 with wider heating conductors formed,

Fig. 6 in a fifth embodiment, a further heating device with two identical Heizleiteran arrangements in series,

Fig. 7 in a sixth embodiment, a further heating device similar to two Heizeinrich lines of Fig. 6 in series,

FIG. 8 in a seventh embodiment a further heating device similar to FIG. 7, in which, in the series connection, the first and fourth heating conductor arrangements are designed differently than the second and third heating conductor arrangements,

9, in an eighth embodiment, a modification of the heating device from FIG. 8, the first and fourth heating conductor arrangements having been replaced by flat heating conductors,

FIG. 10, in a ninth embodiment, a modification of the heating device from FIG. 9 with a very narrow first and fourth heating conductor and a second and third heating conductor arrangement in between with very large meshes,

11 shows a great enlargement of the heating conductor arrangement similar to FIGS. 1 and 3 with a variation of the width of the heating conductor,

FIG. 12 shows a representation of a section in an edge region of the heating conductor arrangement similar to FIG. 3, with conductor tracks with connections for a temperature sensor protruding laterally into this section, FIG.

13 shows an enlarged heating conductor arrangement with a free surface area which is completely surrounded by heating conductors, a bore being provided in this free surface area,

Fig. 14 shows the heating conductor arrangement similar to Fig. 3 with a C-shaped cutout that separates a loading area of heating conductors from the rest of the heating conductor arrangement,

15 shows a further possible modification of a heating device similar to FIG. 1 with secondary connection contacts parallel to the connection contacts which are electrically connected to them by means of bridging contacts which can be severed,

16 shows a modification of the heating device from FIG. 7 with an intermediate contact which is provided within the second and third heating conductor arrangement,

FIG. 17 in a tenth embodiment a modification of a heating device similar to FIG. 9 with two intermediate contacts corresponding to FIG. 16, 18 shows a modification of the heating device from FIG. 16 with surface contacts which are arranged on the second and third heating conductor arrangements,

19 shows a modification of the heating device from FIG. 18 with very narrow surface contacts which are arranged on the second and third heating conductor arrangements,

Fig. 20 is an illustration of meshes of heating conductors in enlargement with rounded angles in the corners,

21 shows a modification of the heating device from FIG. 3 with quasi hexagonal narrow meshes,

22 shows a modification of the heating device from FIG. 3 with individual heating conductors bent in an S-shape,

23 shows a modification of the heating device similar to FIG. 3 with alternatively S-shaped bent individual heating conductors,

24 shows a modification of the heating device from FIG. 22 with an insulation layer under the heating conductors and a cover layer over the heating conductors, both layers in a lattice structure,

25 and 26 a large enlargement of a heating device corresponding to FIG. 24 with connection contacts which also have a lattice structure,

27 shows a modification of the heating device from FIG. 9 with a parallel connection of narrow strip-shaped heating conductors and a grid-shaped heating conductor arrangement there between,

28 shows a modification of the heating device from FIG. 14 with a C-shaped cutout which runs in a zigzag shape in the vertical area,

29 shows a modification of the heating device from FIG. 1, in which additional heating conductor tracks run parallel to the connection contacts,

FIG. 30 shows a modification of the heating device from FIG. 19 with differently designed surfaces.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In Fig. 1, a heating device 11 according to the invention is in a first embodiment provides Darge. The heating device 11 has a flat, rectangular, elongated carrier 12 which is flat. The carrier 12 can for example have an electrically insulating ceramic, micanite or a metal substrate with an electrically insulating surface. The Heizein direction 11 has a grid-shaped heating conductor arrangement 14 which covers an elongated rectangular area. In this case, the heating conductor arrangement 14 overlaps on two elongate and parallel connection contacts 16a and 16b made of suitable contact material. Alternatively, it can be provided that the connection contacts 16a and 16b are connected to the heating conductor arrangement 14 overlap, so are applied subsequently, as shown here. On the left, the connection contacts 16a and 16b each end in a contact field 18a and 18b for an electrical connection, for example by soldering or welding. The heating conductor arrangement 14 is advantageously produced in a thick-film process, in particular by screen printing in a known manner. This also applies advantageously to the connection contacts 16 and the contact fields 18.

Instead of a flat carrier 12, a heating device 111 according to a second implementation in FIG. 2 can also be applied to a tubular carrier 112. The tubular carrier 112 advantageously consists of a steel substrate with an electrically insulating surface, which can be formed, for example, by an insulating layer applied to the steel substrate. A heating conductor arrangement 114, which corresponds to that of FIG. 1 per se, can be applied thereon, advantageously also in a screen printing process. In this case, the illustration in FIG. 1 would be a developed heating conductor arrangement of the heating device 111 in FIG. 2.

The connection contacts 16a and 16b run parallel to one another. As can be seen from the enlargement of FIG. 3, the heating conductor arrangement 14 consists of a first plurality of heating conductors 20a with a direction of extent from bottom left to top right and an angle of 45 ° to the connection contacts 16a and 16b. Furthermore, it consists of a second plurality of heating conductors 20b with a direction from bottom right to top left, which is at right angles to the direction of heating conductor 20a and thus also has an angle of 45 ° to the longitudinal direction of connection contacts 16. The heating conductors 20a and 20b meet at connection points 22, one of which is shown by a dashed circle. The heating conductors 20a and 20b are therefore the short rectangular sections between the connection points 22. In these connection points 22, a layer thickness is the same as that of the individual heating conductors 20a and 20b. The heating conductors 20a and 20b together with the connection points 22 are therefore not brought up one after the other or separately from one another, but are advantageously used as a grid pattern in a single printing process or thick film, advantageously with screen printing. A plurality of each heating conductor 20a and 20b runs along a line that is only interrupted by the connection points 22. Due to the uniform design of the heating conductor arrangement 14, in which not only the heating conductors 20a and 20b are formed the same as one another within the group of their same direction, but all the heating conductors 20a and 20b are formed identically except for edge areas 26, are positioned over the surface of the heating conductor arrangement 14 same current densities and thus the same area performance in operation. It can be seen that four heating conductors 20, namely two parallel heating conductors 20a and two parallel heating conductors 20b, form a mesh 24. The meshes 24 are rectangular or square except for the edge areas 26, which will be explained in detail later, in particular all meshes 24 except for the edge areas 26 and adjacent to the connection contacts 16 are identical.

From FIG. 3 it can actually also be seen that even within the connection points 22 the current density is not or only insignificantly higher than in the heating conductors 20a and 20b themselves. This then also applies to a heating power generation and a temperature. Finally, the current that flows through one heating conductor 20a and one heating conductor 20b must flow through exactly one such connection point 22, and then flow back into one heating conductor 20a and one heating conductor 20b.

4, a third embodiment of a heating device 211 according to the invention is Darge provides. A carrier 212 is not shown here with an edge delimitation; in a similar form, for the sake of simplicity, no contact fields are shown at the ends of the connection contacts 216a and 216b. However, this is very easy to imagine in each case. A heating conductor arrangement 214 is provided between the two elongated and parallel connection contacts 216a and 216b. In the middle area this corresponds with its grid shape to the heating conductor arrangement of FIG. 1. Only at the edge areas 226 can be seen how heating conductors 220a and 220b are very long before they meet at connection points with heating conductors of the other direction. Since apart from inhomogeneities within connection points that relate to the flow of current there, the path of the current paths between the connection contacts 216a and 216b is the same length as in the middle area of the heating conductor arrangement 214, the same or a very similar heating output can be achieved here. Nevertheless, it goes without saying that the edge regions 226 are, so to speak, slightly frayed on a small scale, but can run straight on a large scale as in FIG. 1.

5 shows a fourth embodiment of a heating device 311 according to the invention, which essentially corresponds to that from FIG. 4, in particular within edge regions 326 of a heating conductor arrangement 314 means that due to the almost double width of the heating conductors 320a and 320b of the heating conductor arrangement 314 fewer heating conductors are provided overall than in FIG Heating device 211 from FIG. 4. 6 shows a fifth embodiment of a heating device 411 according to the invention. The heating device 411 has two heating conductor arrangements 414a and 414b, which are obviously identical. Each heating conductor arrangement 414a and 414b covers an elongated rectangular strip-shaped surface. However, here the current flow is not transverse to the longitudinal direction of the heating conductor arrangement 414, as in the previous embodiments, but longitudinally. Two connection contacts 416a and 416b are provided on the left, and a connection contact 416c is provided on the right, which connects the two heating conductor arrangements 414a and 414b in series with one another. This must be taken into account when dimensioning the specific resistance of the material of the heating conductors 420a and 420b, as is the case with the supply voltage. A current path of the series connection between the connection contacts 416a and 416b is many times longer than, for example, in the heating device of FIG. 11. Here, too, a mixture of series connection and parallel connection of the individual heating conductors 420 can be seen.

7 shows a sixth embodiment of a heating device 511 according to the invention, with two connection contacts 516a and 516b to the outside, with four heating conductor arrangements 514a to 514d being provided in between as a series circuit. Further connection contacts 516c, 516d and 516e establish the series connection. Thus there is an even greater length of a current path to the outside between the connection contacts 516a and 516b. This must be taken into account when dimensioning and especially when selecting the specific resistance for heating conductors 520a and 520b. Furthermore, it is noticeable in the heating device 511 of FIG. 7 that there are two or a maximum of three meshes in the direction of the width of a heating conductor arrangement 514, while there are four meshes in the heating device 411 in FIG. 6 and in the heating device in FIG 3 eight complete stitches. At the same time, it can be seen that, unlike in the heating device 411 of FIG. 6, the meshes are closed towards the edge regions, that is to say they are completely current flowed through and thus also participate in the heating effect.

In Fig. 8, a seventh embodiment of a heating device 611 according to the invention is Darge provides. It is designed similarly to the heating device 511 of FIG. 7, but here different types of heating conductor arrangements are provided on a carrier 612. A heating conductor arrangement 614a connects to a connection contact 616a, which is very long in relation to its width. It is designed similarly to the heating conductor arrangement 514a of FIG. 7, only with significantly smaller meshes. On the right at its end, a connection contact 616c is seen, which connects it in series with the second heating conductor arrangement 614b. The second heating conductor arrangement 614b is almost identical to a third heating conductor arrangement 614c, which runs parallel thereto and is only slightly shorter. The two are connected via a connection contact 616d. The heating conductor arrangements 614b and 614c have their width also three meshes next to each other like the heating conductor arrangement 614a. A width of the heating conductors of the heating conductor arrangements 614b and 614c is the same as in the heating conductor arrangement 614a. However, the meshes are larger or have a significantly larger area. They are all closed at the edge areas.

A fourth heating conductor arrangement 614d connects to the heating conductor arrangement 614c by means of a connection contact 616e and has the connection contact 616b to the outside on the left. The heating conductor arrangement 614d is designed in principle identically to the heating conductor arrangement 614a, only a little shorter. A heating device 611 can thus have a plurality of heating conductor arrangements 614a to 614d which can generate different surface power densities. The four heating conductor arrangements 614a to 614d are connected in series here, but this does not have to be the case. They could also all be electrically connected to one another in parallel or in a combination of parallel connection and series connection.

In Fig. 9, an eighth embodiment of a heating device 711 according to the invention is Darge provides. It is designed in a manner similar to the heating device 611 of FIG. 8. However, a first heating conductor arrangement 714a and a fourth heating conductor arrangement 714d as the additional heating conductor arrangement mentioned at the beginning, each with connection contacts 716a and 716b, are designed over the entire surface as elongated strip-shaped heating conductors corresponding to the supply mentioned at the beginning. set heating conductors. A second heating conductor arrangement 714b and a third heating conductor arrangement 714c, which have an identical pattern to one another but slightly different lengths, are designed in a grid shape with a maximum width of four meshes. Connection contacts 716c, 716d and 716e are provided for the electrical connection.

With such a heating device 711 on a carrier 712, in comparison to FIG. 8, yet another division of different area outputs can be achieved. In this way, the first heating conductor arrangement 714a and the fourth heating conductor arrangement 714d can produce very high surface outputs, which are desired in the areas they cover. In the strip-shaped area in between, in which the heating conductor arrangements 714b and 714c run, the area output can be somewhat lower, but nevertheless be distributed very evenly. The heating conductor arrangement 714a is formed by a single wide heating conductor 721a. Correspondingly, the heating conductor arrangement 714c is formed by a single wide heating conductor 721d.

In FIG. 10, a ninth embodiment of a heating device 811 according to the invention is Darge, which is designed similar to the heating device 711 of FIG. Two heating conductor arrangements 814a and 814d are formed on a carrier 812, which are connected by means of two connection contacts 816a and 816b can be electrically contacted from the outside. The heating conductor arrangements 814a and 814d or the heating conductors 821a and 821d are, so to speak, full-surface, but significantly narrower than in Fig. 9. They are connected in series with a second heating conductor arrangement 814b and a third heating conductor arrangement 814c via connection contacts 816c, 816d and 816e. The heating conductor arrangements 814b and 814c are grid-shaped, but with very large meshes and a width of the heating conductor as shown in FIG. 9. Here, a maximum of two meshes are provided in the direction of the width of the heating conductor arrangements 814b and 814c. However, there is a noticeably lower area performance than in the heating device 711 of FIG. 9.

The heating conductor arrangement 814a is formed by the single heating conductor 821a, and the heating conductor arrangement 814d is formed by the single heating conductor 821d. Here, too, similar to the heating device 711 of FIG. 9, a relatively high area output can be generated in each case in a strip-shaped region. In the area in between, i.e. where the heat conductor arrangements 814b and 814c run, the area performance is advantageously significantly lower, for example lower by a factor of 2 to 4.

In Fig. 11 an enlargement of a heating conductor arrangement 14 ‘is shown to show once again how heating conductor 20a‘ according to a direction from bottom left to top right and heating conductor 20b ‘with a direction perpendicular to it each mesh 24‘ bil the. Each mesh 24 is so surrounded by four heating conductors 20 ‘and four connection points 22‘. Above all, it can be seen here how a width of the heating conductors 20a ‘and 20b‘ can vary. In the lower area, the heating conductors 20a ‘and the heating conductors 20b‘ have a width B1. The width B1 can be 0.4 mm, for example. The bottom row of completely dargestell th meshes 24 ‘is exactly square.

In the second row of fully illustrated meshes 24 'seen from below, the width of the heating conductors 20a' and 20b 'increases to a width B2, which can be 0.5 mm, for example, that is 25% greater than the width B1. This increase in width is strictly monotonic, but not exactly continuous or not uniform. At a short distance from each connection point 22 ', for example approximately the respective width of the heating conductors 20a' and 20b 'accordingly, these heating conductors have a constant width before the increase in width begins. Thus, the second row and third row of meshes 24 'seen from below are not exactly square, only the top fourth row of fully illustrated meshes 24' is again exactly square. Since the distance between the longitudinal center axes of the heating conductors 20a 'and 20b' does not change, but rather only the width of the heating conductors, so to speak, the area of a mesh 24 'in the top row is somewhat smaller than that of a mesh 24' in the bottom row. However, the change in the width of the heating conductors 20a 'and 20b' primarily affects their electrical resistance and thus the heating power they generate. This means that with a constant current flow, which must be the case, there is a higher area performance in the lower area than in the upper area with the wider heating conductors.

11 it is easy to imagine how the width of the heating conductors can also vary several times or, for example, can decrease again to the width B1 or another different or smaller width. It is also easy to imagine that only the heating conductors in one direction have a varying width, while the heating conductors in the other direction have a constant width.

From FIG. 11 it is also easy to see that the variation of the electrical resistance of the heating conductors is very easy to achieve by varying the width and in particular is easier than varying their length, which would be very difficult within a grid that is as regular as possible. A variation of the layer thickness in a thick-layer process is also very difficult and technically not easy to achieve consistently. The variation shown in the width of the heating conductor, on the other hand, is relatively easy to achieve.

In FIG. 12, in an enlarged illustration similar to FIG. 3, an edge region 26 is shown for a heating device 11 '. The heating conductor arrangement 14 here has heating conductors 20a and 20b which form closed meshes 24. A cutout 28 is provided in the lower area, here some heating conductors or some meshes are missing, namely five meshes. The cutout 28 is in turn bounded to the right by heating conductors or closed meshes. From the left, an arrangement of two conductor tracks 29 which open into a temperature sensor 31, shown here as a soldered-on SMD component, protrudes into the cutout 28 or towards it. The temperature sensor 31 can serve to determine a temperature in this area on the carrier 12, for example when the carrier 12 is in direct contact with water on its side facing away from the heating conductor arrangement 14 in order to heat it. Due to the somewhat increased distance between the heating conductors 20 and the temperature sensor 31 due to the cutout 28, the temperature signal is not falsified by the direct heating power of the heating conductors 20a and 20b. At the same time, the temperature sensor 31 does not have to be too far away from them, as a result of which it does not have the correct temperature of the water heated by the heating conductor arrangement 14 or the like. could capture. Furthermore, it can be seen from FIG. 12 that such a cutout 28 in the otherwise regular heating conductor arrangement 14 can be used to reach an area with a reduced area output or heating output generation. Another possible development of the invention is shown in FIG. 13 in the case of a heating device 11 with a heating conductor arrangement 14. Here, a so-called free surface area 33 is formed within the otherwise regularly formed heating conductor arrangement 14 with heating conductors 20a and 20b in different directions that form meshes 24 between them. This has been described above. The free surface area 33 is free of heating conductors 20a and 20b or their meshes 24. Here, so to speak, 16 meshes or the heating conductors that would otherwise form them are missing. In the free surface area 33 a bore 35 is provided, to which, for example, a bolt can be attached or a medium passage ge can be created. Instead of such a bore 35, which runs through a support 12 of the heating device 11, a fastening point for a bolt or the like can also be used. be welded, alternatively an electrical contact can be provided. Due to the distance between the heating conductors 20a and 20b and the bore 35, a temperature can be set in this area in accordance with a heating power, in particular the temperature can be reduced somewhat.

In FIG. 14, as an extension of the heating conductor arrangement 14, similar to FIGS. 1 and 3, Darge shows how an electrical adjustment of a resistance value can be carried out in the case of a heating conductor arrangement 14, which has been described with reference to these figures. In the right area, a cutout with cutout sections 37a to 37c is shown following the right edge area 26, which runs on the right edge area 26 as a cutout section 37a starting at a small distance from the upper connection contact 16a and parallel to it to the left. It cuts through fifteen heating conductors 20 or extends over eight meshes in the horizontal direction. Then it bends downwards at a right angle and cuts through sixteen heating conductors 20 as a cutout section 37b. It runs to just before the lower connection contact 16b and then goes again at right angles to the right as a cutout section 37c, i.e. parallel as above with a small distance from the connection contact 16b. As a result, an area of heating conductors 20 and meshes 24 is electrically separated from the rest of the heating conductor arrangement 14. The electrical resistance of the heating device 11 or the heating conductor arrangement 14 between the connection contacts 16a and 16b is increased, thereby reducing the total heating output.

It is easy to see that this cutout need not necessarily have the three mentioned cutout sections 37a-c. It would also be equally effective if only the two free-cut sections 37a and 37b were provided parallel to the connection contacts 16a and 16b. Then some of the heating conductors 20, which are now separated by the vertical free-cut section 37b, would be electrically contacted. However, because of the longer current path, they would have a significantly lower or hardly noticeable current flowing through them and thus would not develop any noteworthy heating effect. With such a simplified cutout some effort can be saved. The same would apply if only the middle vertical cutout section and one of the other two cutout sections were cut.

Another possibility of influencing the electrical resistance in a Heizein direction 11 is shown in the modification of FIG. As such, the heating conductor arrangement 14 is formed between the connection contacts 16a and 16b as described above. In the right area or towards the right edge area 26, three elongated secondary connection contacts 39a are provided at a small distance and parallel to the upper connection contact 16a, which can consist of the same material, for example. The distance from the connection contact 16a can be small and approximately correspond to its width. An electrical connection between connection contact 16a and secondary connection contact 39a is established in each case via a bridge contact 41a. This advantageously consists of a different material than connection contact 16a and secondary connection contacts 39a, which should be electrically similarly conductive, but mechanically less resistant. It can thus be easily cut through by scoring or by means of a laser, so that the bridge contacts 41a can also be cut through or removed relatively easily.

In a corresponding manner, three parallel secondary connection contacts 39b are provided close to the lower connection contact 16b, each of which is electrically connected to the connection contact 16b via a bridge contact 41b. A length of the current path between the secondary connection contacts 39a and 39b is approximately seven full meshes 24, somewhat less than directly between the connection contacts 16a and 16b. By separating the bridge contacts 41a and / or 41b, advantageously beginning on the right towards the edge region 26 and towards the left, specific sections or regions of the heating conductor arrangement 14 can be separated off, similar to FIG. 14 and the cutout. In this way, the heating power generated at the connection contacts 16a and 16b with a fixed voltage can be adjusted. As an alternative to severing the bridge contacts 41a and 41b, the connection contacts 16a and 16b could also be interrupted in the longitudinal course, this interruption then being closed by means of corresponding specially applied bridge contacts and thus electrically bridged. Even if these bridge contacts are then severed, a reduction or miniaturization of the heating conductor arrangement 14 and an increase in the electrical resistance is possible. Alternatively, no such bridge contacts could be provided from the start, but rather they are only provided exactly where they are needed after the electrical resistance has been measured, so that a desired electrical resistance can be achieved. This can save unnecessary material expenditure.

FIG. 16 shows a modification of the heating device 511 corresponding to FIG. 7. Here, with a direction transverse to the longitudinal direction of the central heating conductor arrangements 514b and 514c, an intermediate contact 517 is provided, which acts, so to speak, like a connection contact 516d that has been shifted to the right. The intermediate contact 517 should consist of a material with good electrical conductivity, similar to the connection contacts 516. Thus, the areas of the heat conductor arrangements 514b and 514c to the left of it are electrically deactivated or no current flows through them. This shortens the length of the heating conductor arrangements 514b and 514c and thus their electrical resistance between the connection contacts 516c and 516e and thus reduces the electrical resistance. This can also be a type of electrical adjustment or change in the heating power. Such an intermediate contact 517 can possibly be applied subsequently over the heating conductor arrangements 514b and 514c, for example printed on or glued on. In this way, an adjustment of the entire heating resistor can be achieved.

17 shows a tenth embodiment of a heating device 911 according to the invention, which is basically designed similarly to the heating device from FIG. 9 or FIG provided as heating conductors 921a and 921d. Several connection contacts 916a to 916e are provided, which form a series circuit with the heating conductor arrangements 914b and 914c arranged between the heating conductors 921a and 921d, each of which has a grid shape and a width of three meshes 924. Similar to FIG. 16, an intermediate contact 917 is provided somewhat to the right of the connection contact 916d, which brings about a direct electrical connection. Thus, the area of the heat conductor arrangements 914b and 914c located to the left is separated. In a similar form, an intermediate contact 917 'is provided between the heating conductor 921a and the heating conductor arrangement 914b. This intermediate contact 917 'acts like a connection contact 916c shifted to the left, namely also as a shortening of the respective heating conductor arrangements. Thus, such a shortening by means of an intermediate contact can be provided not only between grid-shaped heating conductor arrangements, but also between a grid-shaped heating conductor arrangement 914b and a wide, full-area heating conductor 921a. FIG. 18 shows, as a further modification of a heating device 511 similar to FIG. 7, how a plurality of surface contacts 543 can be provided over exactly one heating conductor arrangement 514b or 514c. The surface contacts 543 can consist of the material of the connection contacts 516, alternatively of a very good electrically conductive material, which is also easy or good to contact on its surface. In this case, pairs of these surface contacts 543 are provided on the two heating conductor arrangements 514b and 514c in extension to one another. They serve to ensure that an intermediate contact 517 can be applied to such a pair, similar to FIGS The length of the two heating conductor arrangements 514b and 514d can be varied, so to speak, by a short circuit, as a possibility for a relatively precisely staggered predetermined electrical tuning. The surface contacts 543 thus serve to simplify or improve the application of the intermediate contacts 517.

In general, it is considered to be important for the invention that the grid shape of the heating conductor arrangement of the heating device according to the invention can arise, so to speak, by crossing or overlapping heating conductors that run straight. However, a layer thickness of the entire heating conductor arrangement should remain the same as possible, in particular both in the area of the heating conductor itself and in the area of such a connection point. Then both a production is more easily possible and the provision of heating power that is generated as uniformly as possible.

Special thick-film pastes, which can contain graphite, can be used as the material for the production of the heating conductors, in particular for production in the thick-film process. Alternatively, other good electrically conductive materials can be used, which can be used advantageously for the manufacture of heating conductors.

In FIG. 19, as yet another modification of the heating device from FIG. 18, it is shown how surface contacts 543 'are very narrow in a heating device 511' according to the invention. Similar to FIG. 18, these surface contacts 543 'cross the full width of a heating conductor arrangement 514b', which is basically designed similarly to that in FIG. 18. These surface contacts 543 'are clearly shown to be much narrower than in FIG. You can also consist of a material of connection contacts 516c ', alternatively of a very good electrically conductive material, which in turn is easy or good to contact on its surface. A narrow, full-surface heating conductor 521 a 'runs above it parallel to the heating conductor arrangement 514b', for example similar to FIG. 17. For a previously described electrical contact for electrical adjustment, one of the two narrow surface contacts 543 'can be provided by means of an applied, in particular printed, intermediate contact as a type of contact bridge, as indicated by dashed lines on the left with intermediate contact 517'. Thus, the heating conductor 521a 'and the heating conductor arrangement 514b' can be shortened as a comparison of the electrical resistance as previously described be. As a result of the narrow design of the surface contacts 543 ', little material is required for them with, at the same time, sufficiently good electrical conductivity; furthermore, the current flow and the heating behavior in the heating conductor arrangement 514b' are impaired as little as possible. In the upper area, the surface contact 543 'has a widening 544', the shape of which follows, so to speak, that of the two adjacent heating conductors 520 ', that is to say makes maximum use of the available area. As a result of this widening and thus enlargement of the area available at the widening 544 ', the intermediate contact 517' shown in dashed lines can overlap more broadly and thus make better electrical contact. It is also easier to meet area contacts 543 'with an intermediate contact 517', so to speak.

In FIG. 20, a large enlargement of a heating conductor arrangement 14 is shown with heating conductors 20a and 20b which form meshes 24 between them. As a special feature, the meshes 24 in the corners or in their angles are rounded with a radius r, which is drawn as an example. The rounding or rounding is uniform everywhere within a mesh 24 and within all meshes 24. The radius r is approximately 70% of the width of the heating conductors 20a and 20b, which all have the same width. This rounding with the radius r enables, on the one hand, a simpler production or an improved production. Completely pointed corners, as can be seen, for example, from the enlargement of FIG. 11, can be seen in the case of small structures of the widths mentioned of the heating conductor 20 in the range of less than 1 mm, for example 0.4 mm or 0.5 mm, with a screen printing process which has proven itself for thick film processes, not easy to manufacture. This can be improved, so to speak, by the rounding off.

Furthermore, this rounding can increase the area of the connection points 22, so that no current constriction with increased current concentrations, which could lead to damage, can occur here in the corners. Furthermore, a heating power generation can then be reduced in the area of the connection points 22. A temperature increase in the area of the corners, which would occur without rounding, can amount to 4 ° C and even more. This can be reduced or prevented by rounding off. An increase in the temperature in the area of the connection points 22 can also be reduced to less than 4 ° C., as a result of which it no longer has a harmful effect or is hardly noticeable. FIG. 21 shows a modification of a heating conductor arrangement 1014, which can indeed be viewed as a grid-like or as a grid pattern similar to the heating conductor arrangement 14 from FIG. However, the meshes 1024 formed by the heating conductors 1020a and 1020b are approximately hexagonal or in the form of a honeycomb. Alternatively, they could be viewed as diamond-shaped. This results from the fact that the individual heating conductors 1020a and 1020b run in parallel directions to one another, but are offset somewhat parallel to one another, starting from a connection point 1022, and are offset approximately by their own width. As a result, the connection points 1022 are larger than just the pure area of two crossing heating conductors 1020a and 1020b, for example according to FIG. 6. From FIG. 21 it can also be seen that the heating conductors 1020a are approximately 120 ° to one another stand what can be expected with the regular pattern.

In FIG. 22, yet another alternative modification of a heating conductor arrangement 1114 is shown. This corresponds to the above-described further aspect of the invention that the heating conductors 1020a and 1020b do not run straight between individual connection points 1122, but rather curved or twice curved, that is to say approximately S-shaped. As a result of this multiple or double opposing curvature, the heating conductors 1020a and 1020b can be made longer between the connection points 1122 than if they were to run directly. An increase in length can be between 5% and 20% here. This makes it possible, on the one hand, to achieve a somewhat higher resistance value for a material of the heating conductor 1120 with a recommended thickness and width of the conductors due to the increased length, given given resistance values. Furthermore, the course of the heating conductors 1120 can be better distributed over the area covered overall by the heating conductor arrangement 1114. It can be clearly seen here that the heating conductors 1120 are curved twice in opposite directions and are always curved or do not run straight in any section. This could also be different, if necessary, a straight section could be provided just about halfway along where the change in curvature takes place. By avoiding such a straight section, however, the length of the heating conductors 1120 can be made somewhat larger. Furthermore, a distribution over the entire surface of the heating conductor arrangement 1114 can be better for a more uniform heating. The connection points 1122 are formed here, as it were, in that the heating conductors each slightly overlap one another.

From the representation of the heating conductor arrangement 1114 according to FIG. 22 it can be seen that its longitudinal extent is from left to right, as in FIG. 21. The individual heating conductors 1120 could also be seen as a type of continuous corrugated courses or wavy lines , which are each arranged mirror-symmetrically to one another and are applied to one another in the direction transverse to the longitudinal extension from left to right. Essentially however, this corresponds to a rounding of the lattice structure from FIG. 3, which provides exactly straight heating conductors there, which are always arranged in extension to one another.

FIG. 23 shows yet another heating conductor arrangement 1214 with heating conductors 1220a and 1220b, which in turn are curved twice in opposite directions in a manner similar to that in FIG. 22. It is also easy to imagine that the pattern of the heating conductor arrangement 1214 according to FIG. 23 is produced by upsetting in the direction from left to right of the pattern of the heating conductor arrangement 1114 from FIG. 22. In addition, the heating conductors 1220 are formed somewhat wider here in FIG. 23.

From FIG. 23 it can also be seen that the length of the heating conductors 1220a and 1220b between the connection points 1222 is 10% to 20% longer than in the case of straight heating conductors arranged in extension to one another according to FIG. 3. The resulting grid pattern is also regularly, although it is different in the longitudinal direction of the heating conductor arrangement 1214 from left to right than in a direction transverse thereto, namely compressed in the longitudinal direction, so to speak. In FIG. 22 the heating conductor arrangement 1114 is compressed, so to speak, in the transverse direction. In the heating conductor arrangement in FIG. 3, this is the same in both directions mentioned.

24 shows a heating device 1311 which is a modification of the Heizeinrich device from FIG. 3, for example. The heating device 1311 has an electrically conductive carrier 1312, for example consisting of a steel substrate. On an upper side of the carrier 1312, which is metallic and therefore electrically conductive, which is not suitable for a heating conductor arrangement, an insulation layer 1346 is applied in a lattice structure. It is formed before geous by a dielectric glass layer and also at normal operating temperatures for such a heater 1311, for example 200 ° C to 500 ° C, electrically insulating. It can be applied by a method mentioned at the beginning with which a heating conductor arrangement is also applied, advantageously using the thick-film method with screen printing. The shape of the lattice structure of the insulation layer 1346 has free spaces 1350 in meshes 1324, in which the normal surface of the carrier 1312, that is to say a steel surface, is thus exposed. It can thus be seen from FIG. 24 that the consumption of material for the insulation layer 1346 can be reduced by about 20% to 30% compared to a full-area coverage of the entire carrier 1312 with the insulation layer 1346, which would otherwise be necessary.

Corresponding to the lattice structure of the insulation layer 1346, in the middle of it, so to speak, a heating conductor arrangement 1314 with heating conductors 1320 runs thereon. pressure, applied to the insulation layer 1346 and baked in a known manner. The heating conductors 1320 also form the aforementioned meshes 1324. Left and right, the heating conductors 1320 are contacted with elongated connection contacts 1316, which have also been applied either before the heating conductors 1320 or after the insulation layer 1346, advantageously as screen printing in a thick-film process. Thus, here too, electrical contact is made to the heating conductor arrangement 1314 in a manner similar to the aforementioned FIG. 1 or 3.

A cover layer 1348 is applied over the heating conductor arrangement 1314 and the connection contacts 1316, which on the one hand is electrically insulating, for example, can have dielectric properties. On the other hand, it is resistant to environmental influences, in particular it protects the heating conductor 1320 and also the connection contacts 1316 against corrosion or permanent contact with oxygen. The cover layer 1348, in particular like the insulation layer 1346, can also be glass-like or designed as a cover glass and be applied in a thick-layer process, in particular screen printing, and then baked.

It can be clearly seen from FIG. 24 that the heating conductors 1320 run, so to speak, centrally in the webs or over the courses of both the insulation layer 1346 with a lattice structure and the cover layer 1348 with a lattice structure. Thus, a width of the heating conductors 1320 can be approximately 1 mm, either constant or somewhat varying, as has been described above with regard to FIG. 11. Even if the width of the heating conductors 1320 varies, they should run in the middle, namely between the insulation layer 1346 and the cover layer 1348, or these two should project over the heating conductors 1320 by the same distance on both sides. In this case, the insulation layer 1346 can protrude or protrude on both sides about 2 mm below the heating conductor 1320. The cover layer 1348 should protrude about 1 mm over the heating conductor 1320 on both sides or overlap on the insulation layer 1346. A sufficiently good insulation against leakage currents and, above all, a high level of protection of the heating conductors 1320 against environmental influences can thus be achieved here.

In accordance with FIG. 1, the connection contacts 1316 should be routed to contact fields that are not shown here. The contact fields must also run on an insulation layer and are not covered by a cover layer.

In the meshes 1324 or free spaces 1350, bores 1335 can be provided through the carrier 1312 in accordance with FIG. Alternatively, bolts, pins or the like, in particular for electrical contacts, can also be attached or welded on. While it was previously explained how much material can be saved for the insulation layer 1346, it can be seen that the material consumption for this cover layer 1348 can also be significantly reduced due to the even narrower strips of the cover layer 1348 over the heating conductors 1320. In comparison to a full-surface design, savings of around 40% to 50% can be achieved.

The strips of the insulation layer 1346 are therefore about 5 mm wide, they should be a maximum of 10 mm wide. The strips of the cover layer 1348 are approximately 3 mm wide, and the heating conductors 1320 themselves are approximately 1 mm wide. The free spaces 1350 within the mesh are approximately 6 mm x 6 mm in size.

25 and 26 show yet another heating device 1411 with a carrier 1412 as a steel substrate. Heating conductors 1420 of a lattice-shaped heating conductor arrangement 1414 similar to FIG. 24 run centrally on an insulation layer 1446 in a lattice structure according to FIG. 24. The geometric dimensions, materials and application methods also correspond to those from FIG. 24. Instead of the strip-shaped connection contacts in FIG. 24, connection contacts 1416 are here in lattice form or as a lattice structure, as mentioned at the beginning. The lattice-shaped connection contacts 1416 are applied to the heating conductor 1420, advantageously printed on, specifically on connection sections 1420 'pointing to the left. It can thus be achieved that not only the insulation layer 1446 and a cover layer 1448 over the heating conductor 1420 can be designed in a lattice structure and thus material-saving, but also the connection contacts 1416. This can generally be an advantage for heating conductors 1420 with a lower current density in the contact area where a minimum conductor track width is restricted or restricted by inaccuracies in production, for example by screen printing. The material consumption for the connection contacts 1416 can be adapted to the conductor cross-section actually required, as can the current densities that actually occur. In addition, when a current density decreases, by varying the mesh size of the lattice structure of the connection contacts 1416, the conductor track width and possibly also the layer thickness of the connection contacts 1416, their conductor cross-section can be adapted to such a decreased current density. For such thin individual conductors of the lattice-shaped connection contacts 1416, the width of which can be 0.1 mm to 0.3 mm, for example, a very high silver-containing thick-film paste or a correspondingly high silver-containing resistance material can be used, the electrical resistance of which is very low. However, since the consumption is extremely low, overall cost advantages can be achieved. It can be seen that a cover layer 1448 is applied over the heating conductors 1420 and over the connection contacts 1416, as has been described above for FIG. 24. It covers the connection contacts 1416 with the exception of contact fields (not shown) and thus protects them from external influences, in particular corrosion. Here, too, the heating conductors 1420 run, so to speak, in the middle or centered within the lattice structure of the insulation layer 1446 and the cover layer 1448.

In FIG. 26, based on FIG. 24, a left upper corner region of the heating device 1411 is shown, so to speak, while in FIG. 25 a left lower corner region is shown, so to speak. The grid structures of the two connection contacts 1416 and 1416 'in FIG. 26 are different. The individual conductor width of the connection contacts is the same, but in FIG. 25 four individual conductors are, so to speak, extended in a zigzag shape along the length of the connection contact 1416. In FIG. 26, three conductors are, so to speak, extended in a zigzag shape corresponding to the longitudinal course of the connection contact 1416 ′. Thus, for example, a configuration according to FIG. 11 with different widths of the heating conductors 1420 and the respective current densities can be achieved. The meshes 1424 or the free spaces 1450 are not only square or rectangular here, but square.

In FIG. 27, as a modification of the heating device 711 from FIG. 9, a heating device 1511 is shown which has a carrier 1512 with an insulation layer 1546 on the surface of the carrier 1512 according to FIG. 24, on which a heating conductor arrangement 1514 is then applied . An elongated connection contact 1516 is provided on the left and right between two connection contacts 1516. Between the two connection contacts 1516 four parallel narrow heating conductors 1521 run at the top, four parallel narrow heating conductors 1521 also run in the same way at the bottom Heating conductors 1520 and 1521 and the connection contacts 1516 are, as has been explained above, covered with a covering layer 1548, with free spaces 1550 being provided in the area of heating conductors 1520. The heating device 1511 of FIG. 27 is thus a parallel connection, by means of which a more homogeneous temperature distribution in the heating device 1511 is possible.

In FIG. 28, as a modification of the heating device 11 from FIG. 14, a heating device 1611 is shown with a carrier 1612, on the upper side of which an insulation layer (not shown) and two parallel, horizontally extending connection contacts 1616 and a heating conductor arrangement 1614 run. The individual heating conductors 1620 of the heating conductor arrangement 1614 do not form square meshes as in FIG. 14, but rather diamond-like meshes 1624. They are therefore also similar to those in FIG Cutout section 1637b. The horizontal cutout sections 1637a and 1637c are carried out in a straight line. Otherwise there may be malfunctions in the operation of the heating conductor arrangement 1614. The angle at which the individual heating conductors 1620 are severed along the vertical cutout section 1637b should be as close as possible to a right angle, advantageously at least 45 ° or at least 55 °. This angle is about 60 ° here. As a result, the zigzag curve shown here of the Freischnittab section 1637b comes about.

In the heating device 1711 of FIG. 29, two parallel connection contacts 1716 are arranged on a carrier 1712 with an insulation layer 1746 thereon. A grid-shaped heating conductor arrangement 1714 with individual heating conductors 1720, which form square meshes 1724, extends between these. As a special feature, three transverse heating conductor tracks 1723 are provided, which consist of the same material as the heating conductors 1720 and are advantageously applied in the same step. They run through connection points 1722 of the heating conductors 1720 or the meshes 1724. They increase the safety during the operation of the heating device 1711 if hot spots and thus local overheating arise due to hotspots, for example due to calcification on one side of the medium, which leads to a burn through or destruction of one of the heating conductors 1720. Around this heat conductor 1720 which has been burned and destroyed, so to speak as an essentially small or point-like area, there are then increased current concentrations of a current flow between the two connection contacts, based on the local overheating. These current concentrations then lead to further heating conductors being burned out. This burning through or destruction can then be continued along one of the linear heating conductor tracks 1723 to one side or to both sides, namely approximately parallel to the connection contacts 1716 until the entire heating conductor arrangement 1714 is severed in between. Then there is no more current flow at all through the heating conductor arrangement 1714, which is irreversibly destroyed.

Due to the course of the heating conductor tracks 1723 transversely to the main current flow direction between the connection contacts 1716, the heating conductor tracks 1723 do not act at all when the heating conductor arrangement 1714 is operating properly, and therefore do not interfere either.

Another heating device 1811 is shown in FIG. 30. There, on the one hand, the heating conductors 1820 of the heating conductor arrangement 1814 are in the form of meshes with a shape corresponding to FIG 23, but still narrower or more compressed in the horizontal direction. In a modification of the surface contacts 543 of the heating device 511 from FIG. 18 or the surface contacts 543 'of the heating device 51 V from FIG. 19, surface contacts 1843 are designed here so that a wide or rectangular field 1825 of heating conductor material between two sections of heating conductors 1820 is provided. A surface contact 1843 made of a much better conductive contact material, similar to the aforementioned connection contacts, is applied to it or below it. These surface contacts 1843 are designed to be narrow wedge-shaped and begin to be pointed at one end up to a widening 1844. As a result, a better adjustment of the heating device 1811 is possible in some cases.

FIG. 30 also shows that, in addition to the surface contacts 1843, a connection contact 1816 of two parallel strip-shaped heating conductor arrangements 1814, as can be seen, for example, from FIG becomes narrower towards both ends. Contact material can thus be saved, since less current flow is to be expected at the ends of the connection contact 1816 than in the central area, where it is wider.

Claims

1. Heating device with: a flat, extended carrier, two connection contacts, at least one heating conductor arrangement on the carrier, which is connected to the terminal contacts for electrical connection, the heating conductor arrangement having a plurality of heating conductors, the heating conductors are connected to one another at connection points, the heating conductors are connected in total in parallel and series connections between the connection contacts, at least three heating conductors each form a closed mesh and at least three heating conductors are connected to each other at the connection points, the heating conductor arrangement is applied to the carrier in a layered process with a layer structure.

2. Heating device according to claim 1, characterized in that at least 80% of the connection points have an equal number of heating conductors connected to them, preferably at least 95% of the connection points.

3. Heating device according to claim 1 or 2, characterized in that exactly three heating conductors or exactly four heating conductors meet at the connection points.

4. Heating device according to claim 3, characterized in that at a connec tion point at which exactly four heating conductors meet, the respective opposite heating conductors extend exactly to one another.

5. Heating device according to one of the preceding claims, characterized in that at least 80% of the heating conductors run straight, preferably at least 95% of the heating conductors.

6. Heating device according to one of claims 1 to 4, characterized in that at least 80% of the heating conductors are curved, preferably two-fold countercurrently curved, in particular a length of a doubly curved heating conductor between the connection points at its ends at least 5% longer than the straight extension between these connection points, preferably at least 10% longer.

7. Heating device according to one of the preceding claims, characterized in that at least 80% of the heating conductors have the same length, preferably at least 95% of the heating conductors, in particular at least 80% of the heating conductors also having the same shape.

8. Heating device according to one of the preceding claims, characterized in that an angular range between two adjacent heating conductors at a connection point is not angular but rounded, preferably rounded is formed with a radius of at least 2%, in particular 5% to 100% , the maximum width of the heating conductor is rounded.

9. Heating device according to one of the preceding claims, characterized in that different widths are provided for the heating conductors with a variation of the width of a maximum of 40%, in particular with a variation of the width of a maximum of 25%.

10. Heating device according to claim 9, characterized in that a variation of the width is designed such that a heating conductor has a constant width over an extension between the two connection points at its ends.

11. Heating device according to claim 9, characterized in that a variation of the width is designed such that a heating conductor has a varying width at its ends over an extension between the two connec- tion points, preferably the width of the heating conductor from one connection point to the other connection point increases monotonically.

12. Heating device according to one of the preceding claims, characterized in that a layer thickness of the heating conductor arrangement or the heating conductor varies by a maximum of 10%, in particular by a maximum of 2%, the layer thickness of the heating conductor and the heating conductor arrangement preferably being the same everywhere.

13. Heating device according to one of the preceding claims, characterized in that several connection points in one area of the heating conductor arrangement have only two heating conductors, these heating conductors preferably being the other heating conductors. speak, with these connection points in particular lying in an edge region of the heating conductor arrangement or adjoining a free surface area within the heating conductor arrangement.

14. Heating device according to claim 13, characterized in that a cutout in the edge area of the heating conductor arrangement is provided in the form of an indentation in an edge area, two or three heating conductors being connected to one another, in particular, preferably in the area of the indentation at the adjacent or external connection points exactly one heating conductor or exactly two heating conductors less than on the other heating conductor arrangement.

15. Heating device according to one of the preceding claims, characterized in that a free surface area within the heating conductor arrangement is free of heating conductors and connection points, wherein the free surface area is preferably framed by heating conductors, in particular by heating conductors in a straight extension or extension to one another, wherein two or three heating conductors are preferably connected to one another at several connection points adjoining the free surface area.

16. Heating device according to claim 15, characterized in that the free surface area between ten and fifty times, in particular between fifteen and thirty times, corresponds to the area of a mesh.

17. Heating device according to one of the preceding claims, characterized in that a surface heating power varies within the area of the heating conductor arrangement by a maximum of 25%, preferably by a maximum of 10%.

18. Heating device according to one of the preceding claims, characterized in that secondary connection contacts are connected to each of the connection contacts which are opposite one another in pairs in a direction perpendicular to a longitudinal course of the connection contacts, the auxiliary connection contacts each having a connection contact are connected, are separated from each other and are each electrically connected to the connection contact by means of bridge contacts, wherein preferably the bridge contacts can be severed by lasers or mechanical scratching for the electrical adjustment of the heating device to a predetermined resistance value.

19. Heating device according to one of the preceding claims, characterized in that surface contacts are applied to a heating conductor arrangement, which are strip-shaped are formed and which cover at least part of a width of a heating conductor arrangement in the direction transverse to its longitudinal extent and make electrical contact, preferably the surface contacts can be partially covered with electrically highly conductive material that is on an adjacent connection contact or an auxiliary connection contact or on overlaps an adjacent heating conductor arrangement and makes contact there, in particular the width of a surface contact in the direction of the adjacent connection contact, the secondary connection contact or the adjacent heating conductor arrangement is greater, in particular at an end pointing in this direction, preferably at least 50% wide will.

20. Heating device according to one of the preceding claims, characterized in that it has at least one additional heating conductor arrangement which has two additional connection contacts and a single flat additional heating conductor in between, the additional heating conductor preferably being elongated between the two additional heating elements. Connection contacts.

21. Heating device according to claim 20, characterized in that a length of the additional heating conductor is greater than its width, preferably at least ten times greater.

22. Heating device according to claim 20 or 21, characterized in that a width of the additional heating conductor is less than a width of the heating conductor, preferably a width of the additional heating conductor is less than 50% of the width of the heating conductor.

23. Heating device according to one of claims 20 to 22, characterized in that a length of the additional heating conductor is between 90% and 150% of the length of the heating conductor, preferably between 100% and 120%

24. Heating device according to one of claims 20 to 23, characterized in that at least two heating conductor arrangements and at least two additional heating conductor arrangements are arranged on the carrier, preferably all connected in series, in particular the heating conductor arrangements and the additional heating conductor arrangements running parallel to one another and two heating conductor arrangements run between the two additional heating conductor arrangements.

25. Heating device according to one of the preceding claims, characterized in that a mesh is approximately hexagonal or in the form of a honeycomb, preferably exactly hexagonal, in particular four longitudinal sides of the hexagon are each formed by a single heating conductor and two longitudinal sides of the hexagon are each formed by an elongated connection point, the heating conductors preferably being longer than the elongated connection points.

26. Heating device according to one of the preceding claims, characterized in that an insulation layer and / or a dielectric layer is provided between the heating conductor and the carrier, which is at least as wide as the heating conductor and a maximum of 10 mm wider than the heating conductor on both sides of the heating conductor and a maximum of 10 mm protrudes under the heating conductor on both sides, in particular a maximum of 2 mm, whereby preferably the course of the insulation layer and / or the dielectric layer corresponds to the course of the heating conductor, with the insulation layer and / or the dielectric layer having free spaces within the mesh Insulation layer and / or without a dielectric layer.

27. Heating device according to one of the preceding claims, characterized in that a cover layer is provided over or on the heating conductor, which is at least as wide as the heating conductor and a maximum of 10 mm wider than the heating conductor on both sides of the heating conductor and a maximum of 10 mm protrudes beyond the heating conductor on both sides, in particular a maximum of 2 mm, the course of the cover layer preferably corresponding to the course of the heating conductor, the cover layer having free spaces within the meshes without a cover layer.

28. Heating device according to one of the preceding claims, characterized in that at least one of the connection contacts is designed as a grid structure, preferably all connection contacts which are connected to the heating conductor arrangement or heating conductors, in particular the grid structure of the at least one connection contact meshes with free spaces therein having.

29. Heating device according to one of the preceding claims, characterized in that the heating conductor arrangement or its heating conductor are severed along free cut sections, with free cut sections preferably beginning at an outer edge region of the heating conductor arrangement and separating a closed area of the heating conductor arrangement in such a way and thereby severing the individual heating conductors that the closed surface is electrically separated from the rest of the heating conductor arrangement and is electrically insulated.

30. Heating device according to one of the preceding claims, characterized in that linear paths of heating conductor material are provided transversely to a general current flow direction through a grid-shaped heating conductor arrangement between two connection contacts, the linear paths of heating conductor material preferably running through connection points of the heating conductors or the meshes.