FI83720C - PLAN KERAMISK FORMKROPP. - Google Patents

Description

1 83720

Flat ceramic molding

The invention relates to a planar ceramic shaped body which is provided with an electric resistance coating on its opposite side to its front side. An electrical resistance coating is understood to be a coating which, although electrically conductive, is poorly electrically conductive, so that the electrical energy applied to it is converted into thermal energy.

Room radiators are generally placed below the window openings so that the room air they heat rises above the window openings and thus forms a warm air curtain in front of the window opening. Radiators mounted on the walls also generate a certain air flow from the floor to the ceiling of the space heated by them, whereby the heat radiated by the radiator to the room 15 is of only insignificant significance.

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

20 The state of the art also includes underfloor heating, in which heating coils filled with a liquid heat carrier are placed on the floor or below the top floor covering, but also electric heating conductors. However, underfloor heating is relatively detailed and expensive in construction and requires relatively expensive control.

Thus, there is a need to make the actual elements that make up the space delimitation so that they can take care of the heating function of a particular space or space delimitation to be heated individually or in groups or as a substantial part of it.

Examples of such space-forming elements are ceramic moldings, called tiles, which are used as floor or wall curtain tiles for residential, commercial and office spaces, but also for 2,83720 sanitary spaces, sports and swimming pool walls or floors and roofs. However, such ceramic moldings may also be molded bricks for swimming pool upholstery and the like.

5 The prospectus, bearing the business name Canespa KG, 3005 Hemmingen-

Westerfeld, published by Gutenbergstrasse 13 in 1975, can already be seen in the wireless heating system "Canespa-Therm", in which a thermal-10 lacquer layer is placed on the back of the moldings and specifically the ceramic tiles as an electrical resistance coating. This layer of thermal varnish is covered with a polyurethane foam body. However, this system was unable to become more widespread due to the recurrence of local overheating with the consequent detrimental expansions, which even led to endangerment of people and objects.

The flat shaped bodies used so far have a maximum dimensions of 30 x 30 cm, because they can only be manufactured by the dry pressing method up to these dimensions when it is desired to achieve the lowest possible tile-20 thickness.

.· * If, for example, a wall surface is to be covered with such tiles to heat a room, then l. such tiles are then needed a lot and therefore also an equal number of electrical connection and connecting elements.

25 In addition, seams are left between the individual tiles, forming temperature openings, so that the amount of radiant surface available in the upholstered wall is significantly reduced.

DE patent application 1 924 202 and unpublished DE patent application 3 325 204 disclose a planar electric heating device with a surface carrier comprising a thermocouple and in which the thermocouple is formed by a thin layer of electrically conductive material which is si-: - coated on the upper surface of the carrier. Even when, as described in DE patent application 3 325 204, the electrically conductive material consists wholly or partly of a semiconductor material 3 83720, no result is obtained, since such a material cannot be made layers reproducible with respect to their electrical resistance. The heating devices thus have different heating powers in different pieces.

The object of the invention is therefore to propose such a planar ceramic shaped body, by means of which it is possible to form the radiant surface available in the wall, ceiling or floor surface to be coated optimally, to cope with as few connecting and connecting elements as possible and to guarantee even heat.

The object based on the invention is solved by a shaped body having the features of claim 1.

If, for example, a surface of 120 x 15 120 cm has to be covered with tiles, then when 30 x 30 cm tiles are used for coating, which has been common so far, about 19.8% of the total surface area is wasted, which is not available for radiation. for. This wasted area is reduced to 8.8% when applying the proposal according to the invention when using said type and 60 x 60 cm tiles. These values can be further improved by further increasing the surface dimensions of the tiles.

. . There are already tiles made by the applicant of this patent, with dimensions up to 200 x 200 cm, which can be provided with corresponding resistance coatings and which also achieve the desired decoration by separating and combining them with tiles of smaller dimensions. No overheating, especially local overheating, has been observed based on the experience of the patent applicant.

30 Thus, a heating element in the form of a radiant heating element can be obtained, which can, for example, cover the entire wall, ceiling or floor surface and affect the entire volume without the need for room air circulation. In the absence of cooling air-35 circulation, the same feeling of well-being is achieved in the room at a much lower temperature 4,83720, which results in significant energy savings.

The heated, ceramic shaped body according to the invention provides uniform surface heating, because the shaped bodies are accurately reproducible with respect to their heating power.

Even if local faults occur in the electrical resistance coating, the heating effect is practically not interrupted. Although the heating output decreases very little in some places, 10 it does not switch off completely. Besides, there are no local overheats.

The electrical resistance coating may comprise a single layer of aging-resistant plastic with an electrically conductive additive, for example a pure graphite additive, and be structured such that the layer has the necessary resistance value according to the required electrical power.

The resistance value can then be adjusted to values ranging from a few ohms to several kiloohms, in particular by changing the proportion of conductive, e.g. graphite additive, and / or by changing the layer thickness. The layer thickness is usually 10 to 50.

In a tile measuring 100 x 100 cm, the power input is. for example about 100 W, in a 60 x 60 cm plate about 30 W.

In the case of a layer selected according to the invention, aging resistance means a resistance under a stress of up to about 100 ° C which exceeds the service life of the ceramic body.

In an alternative construction of the invention, the electrical resistance coating consists of an electrical resistance foil having a polyester-30 surface layer, an electrically conductive intermediate layer with supply and discharge lines, e.g. a graphite and / or carbon black layer as a resistance layer and a polyester base layer. Such resistance foils are already known per se. The supply and discharge lines associated with the resistive layer are generally made in the form of copper strips. However, a problem with the use of such resistance foils is that the polyester layers adhere only poorly to the resistance layer, so that a ceramic molding with such a resistance foil, e.g. a ceramic tile, on the opposite side to the surface side does not adhere to the plastered wall 5 and the backing remain at the point of attachment with sufficient certainty. On the other hand, polyester is recommended for use as a surface and bottom layer material because polyester is very resistant to aging. However, the problem of using a polyester material in the cover and bottom layer of the resistance foil can be solved if, according to a structural variant of the invention, the resistance layer is grouped by area, leaving the areas it does not cover if the group surfaces are electrically connected to each other. and if, in the areas not covered by the resistance layer, holes in the resistance foil are arranged in places.

In this case, it is possible to use an adhesive which adheres only to the plaster and ceramic surfaces, but not at all or only poorly to the polyester surface, because the resistance foil-20 solution has holes in places, for example punched through and fastened in the holes with free or at least partially permeable adhesive. on the side opposite to the surface layer of the ceramic body.

If the ceramic mold 25 thus formed is glued to the plaster layer or the like with the glue normally used for gluing ceramic moldings to wall surfaces or the like, the adhesion then takes place by means of glue loose in or exuding from the holes and thus only a local but correct when using perforated grid sizing, sufficient adhesion of the ceramic shaped body to the substrate provided for its attachment.

It is very advantageous that the electrical resistance coating is made as a resistance glaze. This glaze is already formed in the burnt-35 shaped body and is fixed by burning the shaped body once more. The glaze shall be 6 83720 with a melting point not exceeding 750 ° C. Glazes with a higher melting point have proven unsuitable.

Another possibility is that the adhesive with which the ceramic shaped body 5 is to be attached to the support substrate is formed as an electrical resistor itself. In this case, it is possible to use two different types of adhesive, in which case the adhesive close to the shaped body consists of an electrical resistance material, while the adhesive remaining on the substrate is an electrically insulating adhesive. The adhesives have essentially similar thermal expansion properties and chemical suitability, so that in this way it is possible to attach the ceramic electrical resistor shaped body very simply.

It is true that DE patent application 1 924 202 already discloses the application of 15 electrically conductive glazes to the surface of ceramic moldings. However, this glaze only works to dissipate static electricity, that is, it is so high-ohmic that it is not suitable for heating purposes.

20 As the material of the electrically conductive resistive layer, a material having, when an electric current is applied to it, a temperature flow such that the current reception of the material decreases sharply with increasing heating.

Although DE patent application 3 325 204 mentions that when semiconductors are used as the conductive material of the heating element, it is the semiconductors that would have the desired negative temperature coefficient, but in semiconductors the conductivity normally improves significantly with increasing temperature (Römpp).

The acquisition of the contact function of the electrical resistance coating is expediently effected by means of contact elements arranged symmetrically in the electrical resistance layer. Thus, for example, in square or rectangular tiles, the contact elements may be arranged: "35 along two opposite sides of the tile in the form of contact strips.

7 83720

If the tile is a ceramic tile with a relief structure on the back, then the contact elements are preferably moved into channels at different edges between the projections delimiting them.

According to a further structure of the invention, it is possible to fine-tune the resistance values of the electrical resistance coatings in such shaped bodies to the desired values also afterwards.

According to a further structure of the invention, this is done by reducing the layer thickness of the resistor coating or heating the resist coating in order to increase the resistance value.

When increasing the resistance value of the resistance coating, it is expedient to proceed by reducing the layer thickness of the resistance coating by sandblasting, electro-erosion, brushing or the like, or by heating the resistance layer from the outside with, for example, flame or radiation. It is also possible that an electric current with a much higher intensity than in normal use is passed through the resistor coating. In this case, the structure of the resistance coating 20 changes so that a corresponding increase in the total resistance value is achieved.

The drawing shows in Fig. 1 the back side of a shaped body with an electric resistance layer and contact elements, in Fig. 2 a plan view of a ceramic plate to which an electrical resistance foil is attached, in Fig. 3 a greatly enlarged partial section through the plate of Fig. 2 and in Fig. 4 a section of a resist-coated plate.

In Fig. 1, the number 1 generally denotes a ceramic tile, the dimensions of which are e.g. 85 x 125 cm with a thickness of 0.8 cm. On the back 2 there is an electrical resistance layer. Nume-35 marks 3 and 4 denote strip-like contact elements glued to the electrical resistor layer or otherwise attached to β 83720. The numbers 5 and 6 refer to the power supply wires.

In Fig. 2, generally indicated at 31, a ceramic shaped body consisting, as shown in Fig. 3, of a ceramic plate 41, an adhesive layer 42 and a resistance film 43. The resistance film comprises a polyester cover layer 46 connected by an adhesive layer to the opposite side 45 of the plate. , edge feeds on discharge lines which are copper strips 32 comprising power supply lines 32 ', 33' 10 (Fig. 2), 33 as a resistance layer of a graphite and / or soot intermediate layer 47 and a polyester backing layer 48 through which the ceramic body is glued to a bearing surface, e.g. In the structure-15 example shown, the resistance foil 43 has three tracks 43a, 43b, 43c with a resistance layer material.

Between the tracks 43a and 43b and 43b and 43c there are areas where there is no resistance layer material. Instead, the track 43a is bounded by the guide strip corresponding to the guide strip 32 or 33, 20 to the area 51. Likewise, the track 43 is bounded by the corresponding guide strip to the area 52, while the track 43b is bounded on both sides by the guide lines to the areas 51 and 52. the layers 46 and 48 overlap, there are holes 53 through which the adhesive 42 25 passes and communicates with the adhesive 54 of the bearing surface 50. The separate conductor paths can be connected to each other in the desired manner. Instead of one plate 31, there may be three sub-plates belonging to the respective tracks 43a, 43b and 43c, respectively.

In a possible structure of the conductive intermediate layer or resistance layer, in a structure in which it ... is grouped according to surface area, leaving in place the areas it does not cover, it can be, for example, a meander-type resistance layer arrangement or grouping: several planar but electrically of sublayers in the form of strips, surface pieces or the like which are joined together or still to be joined afterwards.

9,83720

The choice of the appropriate model is based on local conditions and / or technical requirements.

Fig. 4 at 11 shows a ceramic tile coated with a resist layer 12. The brush strength of this resist coating 12 is reduced by a suitable measure, e.g. sandblasting, electric erosion, brushing or the like, in the construction example shown, e.g. by a rotating brush 13, specific strength as shown in range 14 10.

In this case, the conductivity of this layer also decreases, i.e. the surface resistance increases.

Claims (15)

A flat ceramic mold body, which on one side is provided with an electrical resistance layer formed of a material in which non-metallic large specific surface exhibiting electrical conductivity and conductivity in temperature rise not substantially changing particles are embedded in an electrically nonconductive or only poorly conductive carrier substance, and this material has been made such that the resistance layer exhibits an even electrical and thermal conductivity, characterized in that, using a sheet (1, 11, 31) pressed, rolled and burnt by a plastic, ceramic starting material and the thickness of which is in relation to the surface is 1:45 000 and whose surface extent is at least 3600 cm 2, the electrical resistance layer (12, 43) has been formed on the front facing side (2, 45) of the ceramic body (1, 11, 31). 2. A mold body according to claim 1, characterized in that the electrical resistance layer (12) is formed as a layer of an aging-resistant synthetic resin with mixed electrical additives particles, e.g. graphite, and having such a structure that the layer exhibits an electrically resistive value necessary in accordance with the required electrical power. Molding body according to claim 1, characterized in that the electrical resistance layer consists of an electrical resistance film (43), which is at least locally fixed to the side (45) facing from the front (44) of the ceramic mold body (31), preferably lined on the surface, and which consists of a polyester cover layer (46), a conductive intermediate layer (47) provided with tile and cut lines (32 ', 33.), and a polyester lower layer (48), and that the resistance foil facing the front facing the ceramic mold body is glued with an adhesive (42), which adheres the bed to a ceramic surface and to a polyester surface. 4. A molding body according to claim 3, characterized in that the electrically conductive metal layer (47) is a graphite and / or soot layer. Molding body according to claim 3 or 4, characterized in that the resistance layer is distributed surface-wise within the resistance foil, leaving uncovered surfaces, that these parts surfaces are mutually strengthened in electrical connection and that the areas not covered by the resistance layer are provided with open areas. in the resistance foil. 6. A molding body according to claim 1, characterized in that the electrical resistance layer consists of an electrical resistance glaze, the melting point of which does not exceed 750 ° C. Mold body according to claim 3, characterized in that the electrical resistance layer 20 consists of an electrical resistance adhesive. Mold body according to claim 7, characterized in that the electrical resistance adhesive is covered by an electrically insulating adhesive. 9. Mold body according to one or more of the preceding claims, characterized in that, as material for the electrically conductive resistance layer, a material is selected which, upon entering electric current, exhibits such a temperature course that the uptake of the material upon increasing heating 30 strong declines. Mold body according to one or more of the preceding claims, characterized in that the electrical resistance layer is provided with conductive contact elements. Room heater element according to claim 10, ice 83720, characterized in that the conductive contact elements consist essentially of the base material of the resistance layer and that additional particles with high electrical conductivity or the hand-held, are embedded in the to increase the electrical conductivity. the conductive particles are embedded in higher concentration. Mold body according to one or more of the preceding claims, characterized in that the electrical resistance layer is connected to a contact element for electrically connecting the mold body to a power grid via a material which, upon entering Electric Power, exhibits a saturated temperature course that the current is absorbed. in the material when increasing heating strongly decreases. Mold body according to one or more of the preceding claims, characterized in that the layer thickness of the resistance layer is reduced relative to the original coating thickness. Mold body according to one or more of the preceding claims, characterized in that the distribution of the conductive particles is locally densified in the resistance layer. Use of a ceramic molding body according to one or more of the preceding claims as a heated molding body for swimming pool coverings and / or as a heating wall, table, ceiling or floor plate and / or as cover for heating elements.