FI83582B - RUMSUPPVAERMNINGSELEMENT BESTAOENDE AV EN MED EN ELEKTRISK MOTSTAONDSBELAEGGNING FOERSEDD KERAMISK FORMKROPP. - Google Patents

Description

1 83582

The invention relates to a room heating element consisting of a ceramic shaped body, on the opposite side of the façade of which a planar heat source formed by an electrical resistance layer is arranged.

The elements used for the room slope, which are fins or level radiators 10, are generally placed below the window openings so that the heated room air rises above the window openings and thus forms a warm air curtain in front of the window opening. Also in connection with wall-mounted heating devices, there is no movement of air from the floor of the room to be heated towards the ceiling, whereby the heat radiated by the heating device into the room is of only minor importance.

Conventional, room-only radiant heaters placed in rooms have only a very limited radiation zone locally and operate at high temperatures.

The prior art further includes underfloor heating devices in which heating lines are placed in the floor casting or below the top floor layer, to which a liquid heat transfer medium is supplied, as well as electric heating lines. However, underfloor heaters are relatively complex and expensive in construction and require relatively expensive control equipment.

Thus, there is a need to construct the structural elements delimiting the room itself so that they can provide heating of the room or the surface delimiting the room to be heated or kept warm, either as a group or as a substantial part of the space delimiting the whole room.

Examples of such structural elements delimiting the space 35 include ceramic moldings, such as panels used as floor and wall covering tiles for the walls and floors of residential, commercial and office rooms, as well as washrooms, sports and swimming pools. Such ceramic shaped pieces can also be used as shaped tiles for swimming pool cladding and the like.

From a brochure published by Canespa KG, 3005 Hemmingen-Westerfield, Gutenbergstrasse 13, in 1975, a wireless heating system 10 "Canespatherm" is already known, in which a layer of heating varnish formed by an electric resistance layer is arranged on the back of moldings and in particular ceramic plates. This layer of heating varnish is covered by a polyurethane foam element. However, this system has not failed through itself, 15 as it has repeatedly led to overheating and the resulting harmful consequences, which have even endangered human lives and property.

The prior art further comprises an electric room heating element known from DE-A-1 440 971, which has a base with a large smooth surface and a planar, thin heat source which adheres directly to the surface. The substrate then consists of a porcelain or quartzite sheet. On the opposite side of the facade of this plate, an adhesive, thin, planar, metallic heat source film formed by doping a chemical solution is provided, or on this side there is an adhesive heat source film formed of a very thin aluminum layer.

In connection with such a room heating device, it is necessary to provide spacers between the plate and its support surface, whereby a draft duct is again formed for the room air behind the room heating device, which causes all the disadvantages mentioned and described above in connection with other room heating devices. In addition, the metallic resistance layers used have a relatively low resistance value and require high electrical power to reach a sufficient temperature.

DE-A-1 924 202 and unpublished application 3 325 204 disclose a planar electric heater having a planar support element containing a heating element and wherein the heating element is a thin film of electrically conductive material applied to the surface of the support element. Although the electrically conductive material consists wholly or partly of a semiconductor material, as disclosed in application 3,325,204, a proper result is not obtained because the films of such material are not reproducible in terms of their electrical resistance. The heaters thus have different powers from piece to piece.

The object of the invention is to provide a room heating element which not only produces high thermal power with low electricity consumption, is suitable as a structural element of room delimiting surfaces and cannot be installed so that no ducts are created through which the air flows in the room to be heated are circulated. reproducible, i.e. it has the desired thermal power piece by piece.

According to the invention, this object is solved by a room heating element having the features of claim 1.

Non-metallic, high surface area, electrically conductive particles whose electrical conductivity does not substantially change with increasing temperature are preferably graphite or carbon black or a mixture thereof.

With the solution according to the invention, it is possible to provide a room heating element formed by a radiant heating element, which, by amplifying it to the required extent, can cover e.g. an entire wall, ceiling or floor surface which radiates heat evenly or from desired areas. Room air begins to circulate and uniform well-being can be achieved in the room at a substantially lower room temperature of 4,83582, resulting in significant energy savings.

Because the heating elements can be accurately amplified in terms of their thermal power, they can be manufactured in 5 predetermined heating power classes. In this case, any desired thermal radiation distribution can be obtained on the surface covered by them.

Local faults in the electrical resistance layer practically do not cause a loss of heating power. Of course, there will be a slight local decrease in electrical power, but it will not break completely. Nor does local overheating occur.

The electrical resistance layer may consist of a non-aging synthetic resin having an electrically conductive alloying agent, such as pure graphite, and having a structure such that the resistance value of the layer corresponds to the desired electrical power. The resistance value can then be adjusted in the range from a few ohms to several kiloohms and this is done by changing the percentage of the electrically conductive alloy 20 of the resistance layer and / or by changing the layer thickness. The thickness of the layer is normally between 10-50 μ.

A plate with a size of 100 x 100 cm consumes approx. 100 W of electricity, for example, and a plate with a size of 60 x 60 cm is about 30 W.

In accordance with the invention, non-aging means the resistance under continuous loading up to a temperature of about 100 ° C.

In an alternative embodiment of the invention, the electrical resistance layer consists of an electrical resistance film having a polyester cover film, a conductive intermediate layer with inlet and outlet conductors 30, e.g. a graphite or soot layer as a resistance layer and a polyester backing layer. Such resistance films are known per se. The input and output wires of the resistor layer usually consist of copper strips. When such resistive films are used to solve the problem underlying the invention, such a problem is encountered that the polyester films adhere only weakly to the resist layer, so that a ceramic molding with such a resist film on the opposite side of the façade cannot be an adhesive adhering to the wall surface or the back surface of the molded article and the polyester layer. On the other hand, it is recommended to use polyester as a material for the top and bottom layers, because the polyester is very durable without aging. However, the problem of using a polyester material in the top and bottom layers of the resist film can be solved when, according to a modified embodiment of the invention, the resist layer is divided into regions by omitting certain points and the sub-regions are electrically connected to each other. cover, local breaks.

It is possible to use an adhesive which adheres to the plastered and ceramic surfaces, but poorly or not at all to the polyester surface, since the resistance film is locally cut, e.g. stamped, and attached to the opposite side of the ceramic body with a broken or at least partially permeable adhesive. When a ceramic mold made in this way is glued to a plastered or similar surface with an adhesive intended for fixing ceramic moldings to wall surfaces, etc., adhesion takes place by means of an adhesive at or penetrating the broken points, thus providing a local but sufficient gap dimension. attachment of the ceramic shaped body to the substrate.

It is very advantageous to manufacture the electrical resistance layer as a resistance glazing. This glazing is formed on the pre-fired shaped body and fixed by means of the latest 35 burning. The glazing must be selected to have a melting point of not more than 750 ° C. Glazings with a higher melting point have proven unsuitable.

It is of course already known from DE-A 1 924 202 to form electrically conductive glazing on the façade side of ceramic moldings. However, the purpose of this glazing is to remove static electricity, i.e. its resistance value is so high that it cannot be used for heating purposes.

10 Another possibility is to make the adhesive with which the ceramic shaped body is to be attached to the support base itself as an electrical resistor. In this case, it is possible to use two different types of adhesive, in which case the adhesive near the shaped body is formed of an electrical resistance material, while the adhesive against the substrate is of an insulating type. The adhesives have substantially similar thermal expansion properties and are chemically compatible, so in this way it is very simple to attach a molded piece with a ceramic electric resistor.

20 Electrical resistance layer The electrical connection is preferably made by means of connecting elements which are arranged symmetrically in the electrical resistance layer. Thus, for example in square or rectangular plates, the connecting elements can be formed by connecting strips running at opposite edges of the plate. In the case of a ceramic plate with an embossing on the back side, the coupling elements are preferably placed in the channels delimited by the protrusions at opposite edges.

According to an embodiment of the invention, it is possible to fine-tune the resistance values of the electrical resistance layers in such room heating elements to the desired size also afterwards.

According to said embodiment, in order to increase the resistance value, the layer thickness of the resistance layer is reduced or the resistance layer is heated.

7 83582

In order to increase the resistance value of the resistance layer, it is most convenient to reduce the layer thickness of the resistance layer by sandblasting, electroerosion treatment, brushing or the like, or to heat the resistance layer 5 externally, e.g. by flame or irradiation. It is also possible to conduct an electric current through the resistive layer which is considerably higher than in normal use. In this case, the structure of the resistance layer changes so that the resistance value increases.

Fig. 1 shows a rear plate-shaped shaped body with a resistance layer and coupling elements.

Figure 2 shows a sectional view of a plate with the back side embossed.

Figure 3 shows a top view of a ceramic heating element 15 formed by a plate with an electrical resistance film.

Figure 4 shows a greatly enlarged partial section of the plate of Figure 3.

Fig. 5 shows a section of a ceramic plate provided with a resistance layer to explain the fine adjustment of the resistance value.

In Fig. 1, reference numeral 1 generally denotes a room heating element, which here consists of a plate with an electrical resistance layer on the back side 2. Reference numerals 3 and 4 denote coupling elements which are glued to the electrical resistance layer or otherwise attached thereto. Numbers 5 and 6 show electrical wires.

Figure 2 shows a section of a room heating element, which here consists of a plate with the back side 21 30 embossed. In this embossing there are protrusions 22 and recesses 23. On the back side of this plate, i.e. on the side where the protrusions and recesses are, e.g. an electrically conductive adhesive 24 is applied. A conductor 27 is placed in the groove 26 next to the edge 25 of the plate. that is, a material, β 83532, which is conductive but so poorly that the electrical energy supplied to it is converted into thermal energy.

In Fig. 3, the numeral 31 generally denotes a room heating element comprising, as shown in Fig. 4, a plate 41, an adhesive layer 42 and a resistance film 43. The resistance film is formed by a polyester coating layer 46 attached to the opposite side 45 of the plate 41 by the air layer 42. graphite and / or carbon black intermediate layers 43a, 43b, 43c, the input and output wires of the copper strips 32-37 provided with electrical conductors 38 (Fig. 3) and a polyester backing layer 48 glued to the support surface 49, e.g. to the plastered wall with an adhesive layer 50. In the embodiment shown, the resistance film 43 comprises three webs 43a, 43b, 43c which are of resistance material, but can of course be further divided.

Between the webs 43a and 43b and 43b and 43c, respectively, there are areas 51 and 52 (Fig. 3) which do not have a resistance layer material. In contrast, the web 43a is bounded by the conductor strip 36 to the area 51. Likewise, the web 43c is bounded by the conductor strip 33 to the area 52, while the web 43b is bounded on both sides by the conductor strips 34 and 35 to the areas 51 and 52. 46 and 48 overlap, there are cuts 53 through which the adhesive of the layer penetrates and comes into contact with the adhesive on the support surface 49. The individual conductor webs can be connected to each other in any way. Instead of one plate 31, three sub-plates of webs 43a, 43b, 43c, respectively, can also be used.

In a possible embodiment in which the conductive intermediate layer or resistance layer is divided into regions by omitting some regions, the resistance layer may be e.g. knee-shaped or it may be divided into several regional but electrically interconnected or post-connected sublayers which consist of strips, planar pieces, etc. The selection of a suitable pattern design is based on local conditions and / or technical requirements.

In Fig. 5, the number 91 indicates a ceramic plate to which a resistor layer 92 is attached. The thickness of this resistor layer 92 is reduced by a suitable method, e.g., sandblasting, electroerosion method, brushing, etc., by means of a rotating brush 93 so as to reduce its thickness 94 to the target value presented. In this case, the conductivity of this layer also decreases, i.e. the surface resistance increases. In this way, it is possible to fine-tune the resistance value 15 of the layer 92.

Claims (12)

A heating element (1; 31; 91), consisting of a ceramic mold body, which is provided on the front side facing away from the front (2; 21; 45) with a surface heat conductor in the form of an electrical resistance cladding (24,43; 92 ), characterized in that the electrical resistance lining (24; 43; 92) is formed as a resistance layer of a material having a non-metallic, large specific surface, electrically conductive and, at temperature rise, its electrical conductivity, not substantially changing particles. is embedded in an electrically non-conductive or only poorly conductive carrier substance, and this material is applied so that the resist coating has a uniform electrical and thermal conductivity. Heating element according to claim 1, characterized in that the electrical resistance layer (24; 43; 92) consists of an aging-resistant synthetic resin with electrically conductive admixture, such as graphite, soot or the like, and has such a structure that the layer has a the necessary electrical power corresponding to the necessary electrical resistance value. Heating element according to claim 1, characterized in that the electrical resistance layer 25 consists of an electric resistance film (43) which is fixed locally on the surface (45) facing away from the front of the ceramic mold body (31). glued to the surface, and formed of a polyester cover layer (46), a conductive intermediate layer (32-37) and a polyester bottom layer (48), and the resistance foil attached to it from the front the side facing the ceramic mold body by means of an adhesive which adheres to both a ceramic surface and a polyester surface. Heating element according to claim 3, characterized in that the resistance layer (43) within the resist film is distributed surface-free during the release of uncovered areas (51,52), that these part surfaces (43a, 43b, 43c) electrically in contact with each other, and local openings in the resist film are provided in the areas not covered by the resistance layer. 5. Heating element according to claim 1, characterized in that the electrical resistance coating consists of an electrical resistance glazing, the melting point of which does not exceed 750 eC. 10 6. A heating element according to claim 1, characterized in that the electrical resistance lining consists of an electrical resistance adhesive. 7. Heating element according to claim 6, characterized in that the electrical resistance adhesive 15 is covered with an electrically insulating adhesive. Heating element according to any of the preceding patent claims, characterized in that the electrical resistance layer is provided with conductive contact elements. 20 9. Heating element according to claim 8, characterized in that the conductive contact elements consist essentially of the base material of the resistance layer, in which material for increasing the electrical conductivity is added additional particles of high electrical conductivity or the present conductive particles. higher concentration. Heating element according to any one of claims 2, 5, 8 or 9, characterized in that the layer thickness of the resist coating is reduced in proportion to the original application thickness. Heating element according to any of claims 1-12, characterized in that the distribution of the conductive particles is densified locally in the resistance layer. 12. Use of a heating element according to any of the preceding claims as heating elements in swimming pool cladding and / or as a heated wall, table, ceiling or floor plate and / or as heating element coverage.