WO2005027580A1

WO2005027580A1 - Heatable textile product

Info

Publication number: WO2005027580A1
Application number: PCT/EP2003/050630
Authority: WO
Inventors: Steve Verstraeten; Pol Speleers
Original assignee: N.V. Bekaert S.A.
Priority date: 2003-09-17
Filing date: 2003-09-17
Publication date: 2005-03-24
Also published as: AU2003304637A1

Abstract

A heatable textile product comprises a textile cloth, which comprises resistance heating means and at least one integrated electrode for conducting electric current to the resistance heating means. The heatable textile product further comprises at least one additional electrode which is in electrical contact with the integrated electrode at at least two junction points.

Description

HEATABLE TEXTILE PRODUCT

Field of the invention.

The present invention relates to heatable textile product and to a use of such a product.

Background of the invention.

Heatable textiles are widely known. They are known as knitted, woven or non-woven textile fabrics.

Such heatable textiles are known from EP1049354A1 , as an example. Resistance heating means in the form of conductive yarns, are integrated in a knitted fabric where the conductive yarns are spaced one from the other.

In order to have the resistance heating means connected to an electric power supply, like an AC or DC current supply, electrodes are to be foreseen, in order to contact the resistance heating means. Usually the different resistance heating means are in parallel connection to this current supply. As an example, US 5484983 describes a textile product comprising a knitted textile cloth, which has several resistance heating means coupled in parallel to an electric current supply means in the form of an electrode which forms an integral part of the knitted cloth.

electrodes for current supply to the resistance heating means are presently integrated electrodes. There are several contradictory requirements put on these electrode. On the one hand, the electrodes are to be provided in optimal contact with the resistance heating means, in order to avoid unnecessary electrical contact resistances, built up over the system, and in order to avoid sparks during use of the heatable textile. These sparks may be caused by applying an electrical tension over inadequate contacts between electrode and resistance heating means. Electrodes which are fully integrated in the heatable textile product seem to be advantageously. On the other hand, the integrated electrodes are preferably provided using yarns or wires having a lowest possible electrical resistance. This to obtain a resistance built up over the whole system, which approximates the resistance of the resistance heating means coupled in parallel. This may be obtained by either using thicker metal wires or yarns, or using more metal wires or yarns adjacent to each other and working together as one electrode, or using more expensive, more electrically conductive material. In case thicker metal wires or yarns are to be used, the production process of the heatable textile cloth is disordered more easily and requires a less productive production speed, this because the geometry and mechanical properties of the electrode material differs too much from the other yarns used to provide the textile fabric. The use of more metal wires or yarns adjacent to each other as one electrode, provides larger electrodes which may not be excepted due to technical or esthetical reasons. The use of better electrically conductive material usually causes increase of cost of the electrode.

An other problem rises in case the integrated electrode is interrupted. This may cause local heating or overheating of both resistance heating elements and/or electrodes. Also a risk of sparks caused by local electrical tension differences between the two ends of the electrode due to the interruption, cannot be avoided.

Summary of the invention.

It is an object of the present invention to avoid the drawbacks of prior art. It is also an object of the present invention to provide a heatable textile product which may be produced in a more productive way. It is further an object of the present invention to have sufficient electrical conductivity over its electrodes to avoid heating of the electrodes when used. It is an other object of the present invention to avoid to a large extent the risk of sparks in case of rupture of an electrode. The heatable textile product as subject of the invention further has as an object to provide an acceptable contact between electrode and resistance heating means. It is further an object of the present invention to reduce the dimensions of the integrated electrode, integrated in the heatable textile product.

A heatable textile product as subject of the invention comprises a textile cloth. The textile cloth comprises resistance heating means and at least one integrated electrode for conducting electric current to the resistance heating means. The heatable textile product according to the invention is characterized in that the textile product comprises at least one additional electrode, which is in electrical contact with the integrated electrode at at least two junction points. "Integrated electrode" is to be understood as an electrode being integrated in the textile cloth, this means that the electrode is an integral part of the cloth.

Possibly, the heatable textile product comprises two or more than two integrated electrodes, each being an integral part of the textile cloth of the heatable textile product. For some or even for each of the integrated electrodes, an additional electrode may be provided, which makes an electrical contact with one of the integrated electrodes at at least two additional junction points.

According to the invention, for each integrated electrode, a so-to-say backup electrode is provided. This backup electrode assists in conducting the electrical current to the resistance heating elements. In case one of the electrodes is interrupted between two adjacent junction points, the other corresponding electrode still keep the ends of the interruption at substantially the same potential, so avoiding to a large extent spark discharges between the ends of the interruption. Therefore, the distance between the adjacent junction points on the same additional electrode and integrated electrode is preferably less than 5 times the distance between adjacent resistance heating means. Even more preferred, the distance between the adjacent junction points on the same additional electrode and integrated electrode is smaller than or equal to 4 or even smaller than or equal to 3 times the distance between adjacent resistance heating means.

Depending on the dimensions of the textile cloth, and the length of the electrodes, more than 2 junction points, or even more than 5 or even more than 10 junction point may be foreseen between each integrated electrode and corresponding adjacent electrode.

Advantageously, the linear electric resistance of the additional electrode Ra is less than or equal to 1/20 of the linear electric resistance of the integrated electrode Ri. More preferred, Ra is less than or equal to 1/30 of Ri. Preferably the linear electric resistance of the additional electrode is less than 1 Ω/m , or even less than 0.5Ω/m The more the difference in linear conductivity, in favor of a more conductive additional electrode, the more the current, to be supplied to the resistance heating means, will essentially be conducted via the additional electrode, to the different junction places. The integrated electrode will distribute the current between the junction places over the present resistance heating means, which are contacting the integrated electrode between these junction places. Therefore, the amount of electrode material, to be integrated in the textile cloth, can be reduced, without a risk of overheating both electrodes locally. Also the robustness and other mechanical properties of the electrode material which is to be integrated in the cloth can be chosen with regard to the corresponding properties of the other filament or yarn properties providing the cloth. The production process of cloth making can be optimized and simplified.

The additional electrodes, which usually become more robust, are not to be incorporated in the heatable textile product during production of the cloth, which does not disturb the production process of the cloth.

According to the invention, at least two junction places are provided for each additional electrode and corresponding integrated electrode. Both electrodes can make electrical contact with each other by connecting both electrodes using press-studs or rivets. Alternatively, both electrodes are sewn, welded, soldered, glued or embroidered one to the other locally.

The junction places are not necessarily to be located at a connection between integrated electrode and a resistance heating means.

The integrated electrodes, which are an integral part of the textile cloth, may be provided using carbon fibers, or metal or metallic coated fibers. Preferably stainless steel fibers are used. The term "fibers" is to be understood as either staple fibers having a specified staple length, or filaments, being endlessly long.

The metal fibers may be obtained by using Cu, Ni, Ti, stainless or any other suitable metal or metal alloy. Preferably the equivalent diameter of the fibers is in the range of 1 to 100μm, such as in the range of 6 to

40μm, e.g. 8μm, 12μm, 14μm or 35μm. Most preferred, a metal filament yarn, such as Bekitherm® VN yarns or spun yarns comprising or consisting of metal fibers such as Bekinox® fibers are used. The term "equivalent diameter" of a fiber is the diameter of an imaginary circle having a surface, identical to the surface of a radial cross section of the fiber.

In case metal fibers or filaments are used to provide the integrated and/or additional electrode, stainless steel is preferably used. Most preferred, AISI 302, 316, 316L stainless steel alloy is used.

The additional electrodes may be provided using metal or metallic coated fibers. Most preferred, Ag-, Cu- or Al-filaments are used. Alternatively a polymer yarn or filament, being wrapped with at least one metal tape may be used. The additional electrode may comprise several conductive elements, e.g. polymer fibers being wrapped with one or more metal tapes, e.g. Cu-, Al- Ag-tapes or laminates of such, being integrated into a woven band by weaving or braiding. As an alternative for both integrated and additional electrodes, fine cords comprising several , e.g. 28, copper cladded steel filaments having a fine diameter, e.g. 61 μm, may be used. As an other alternative, identical stainless steel cladded copper filaments with diameter 61 μm may be used.

The fineness of the metal wires or yarns used to provide the additional and integrated electrodes may vary over a large range.

The textile cloth may be a woven braided or knitted cloth, using any known textile production method as presently known. Preferably the integrated electrodes are essentially parallel to the selvedge of the textile cloth. The additional electrodes are preferably essentially parallel to their corresponding integrated electrodes.

Such heatable textile products may be used as heatable blankets or sleeping bags, curtains, clothes, car seat heatings or as coverage for mattresses.

Brief description of the drawings.

The invention will now be described into more detail with reference to the accompanying drawings wherein • FIGURE 1 shows schematically to a heatable textile product as subject of the invention. • FIGURE 2a, FIGURE 2b and FIGURE 2c show schematically a detail of the heatable textile product of FIGURE 1 at the cross section according to AA. • FIGURE 3 and F4 show schematically a heatable textile product used as mattress covering means.

Description of the preferred embodiments of the invention.

FIGURE 1 shows schematically a heatable textile product (101 ), e.g. a blanket or a mattress covering. The heatable textile product 101 comprises several resistance heating means 102a and 102b, which are electrically connected in parallel to two integrated electrodes 103 and 104. These integrated electrodes 103 and 104, and the resistance heating means 102a and 102b are an integral part of the textile cloth

105, being e.g. a woven fabric. As an alternative, the textile cloth may be a knitted fabric.

Two additional electrodes 1 13 and 114 are provided to the heatable textile product 101. Additional electrode 113 is in electrical contact with integrated electrode 103 at junction points 123a, 123b and 123c. Additional electrode 1 14 is in electrical contact with integrated electrode 104 at junction points 124a, 124 and 124c.

As an example, each of the integrated electrodes 103 and 104 are provided by weaving 5 stainless steel fiber yarns having a fineness of 250 tex, each yarn comprising 275 filaments of 12μm diameter each, in the textile cloth 105, the yarn being adjacent to each other in the weaving report or pattern. Each of these yarns have a linear resistance of 30 Ω/m. The linear resistance of the integrated electrode Ri is 6 Ω/m. The integrated electrodes are provided in the warp direction of the woven textile cloth 105 and are essentially parallel to the selvedge of the textile cloth 105.

The resistance heating means 102a and 102b, being stainless steel filament yarn comprising 90 filaments of 14μm diameter each, are woven into the textile cloth at a distance of about 4 cm from each other. The linear resistance of these resistance heating means is 70 Ω/m. They are provided in weft direction and are in electrical contact with each to the yarns of the integrated electrodes due to the weaving pattern.

The additional electrodes 1 13 and 1 14 may be a woven tape comprising 25 yarns of PA multifilament yarns, each of the yarns being wrapped with two fine silver plates copper tapes. The linear resistance of the additional electrode Ra is 0.2 Ω/m. The integrated and additional electrodes are brought in electrical contact at several regularly spaced junction points. The distance between adjacent junction points is 16cm to 20 cm. The junction points are not necessarily located at the locations where resistance heating means and integrated electrode are contacting each other electrically. As an alternative the distance between adjacent junction points is chosen 8cm, and the junction points are located in between the connection of resistance heating means and integrated electrode. As an other alternative, the adjacent junction points are spaced 4cm from each other and located either between the connection of resistance heating means and integrated electrode, or located at the connection of the resistance heating means and integrated electrode.

FIGURE 2a , FIGURE 2b and FIGURE 2c , being alternatives for a cut of the heatable textile cloth according to the plane AA', show a cross- section of the junction points 124b and 123b.

In FIGURE 2a, the electrical contact between integrated electrode 104 or 103, and additional electrode 1 14, respectively 113, is provided using press-studs 201. The upper part 202 of the press-stud 201 is connected to the additional electrode 1 14 or 1 13. A lower part 203 of the press-stud 201 is connected to the integrated electrode 104 or 103. Both upper and lower part are connected to each other at location 204. The press stud is provided using electrically conductive material, such as metal alloys, preferably stainless steel. The electrically conductive material of the upper and lower part of the press-stud make electrical contact with each other at location 204, and each of the lower or upper part is in contact with either de integrated or additional electrode.

Possibly, the press stud outer surface 205 is foreseen of electrically insulating layers, e.g. polymer coatings.

The advantage of using press-studs, is that the additional and integrated electrode may be separated one from the other, e.g. for cleaning purposes, or during other production steps, required for providing the heatable textile product.

As an alternative shown in FIGURE 2b, the additional electrode 1 14 or 113, and the integrated electrode 104, respectively 103, are in electrical contact using a rivet 210. The rivet 210 is pierced through both the additional and the integrated electrode. The electrical contact between the additional and integrated electrode may be provided by the pressure force between contact surface 211 of both electrodes, and/or by the contact of the electrically conductive material of the rivet and both of the integrated and additional electrode. The outer surface 212 of the rivet 210 may be provided with electrically insulating layers, e.g. polymer coatings. The rivet is preferably provided using electrically conductive material, such as metal alloys, preferably stainless steel.

As a third alternative, the integrated and additional electrode may be in electrical contact with each other by embroidering or sewing both electrodes at the junction points. FIGURE 2c shows such connection of an additional electrode 114 and integrated electrode 104. both are sewn to each other using a sewing thread 220, which may be a yarn comprising or even consisting of metal filaments.

A heatable textile product as shown in FIGURE 1 , and of which details are shown in FIGURE 2a, FIGURE 2b or FIGURE 2c, may be used to cover mattresses a shown in FIGURE 3.

The mattress comprises an elastic means, like a foam or a spring-based mattress core 301 , which is covered by a heatable textile product 302. The heatable textile product 302 has several resistance heating means 303 and two integrated electrodes 304 and 305, and is provided with two additional electrodes 314 and 315. As shown in FIGURE 3, the heatable textile product 302 covers the whole mattress-core 301 and is closed at the edge 306, e.g. using a zipper. Each additional electrode is electrically coupled to its corresponding integrated electrode at several junction points 307. Each of the additional and/or integrated electrode is coupled to a power supply by means of a connecting means 320, e.g. two cupper lead wires and socket.

As an alternative, shown in FIGURE 4, only one side of the mattress- core 400 is covered with a heatable textile product 401 , whereas the other part of the mattress is covered with non-heatable textile products 402. The heatable textile product 401 and non-heatable textile product 402 are connected to each other at both sides of the mattress core 400 over their edge 403. At each selvedge of the heatable textile product 401 , one integrated electrode 410 is electrically connected to an additional electrode 41 1 at several junction points 412. The resistance heating means 404 of the heatable textile product are connected to these integrated electrodes 410, and via the junction points 412 to the additional electrodes 41 1. The resistance heating means 404 of the heatable textile product 401 are only present at one side 405 of the covered mattress . Each of the additional and/or integrated electrode is coupled to a power supply by means of a connecting means 420, e.g. two cupper lead wires and socket.

Claims

1. A heatable textile product comprising a textile cloth, said textile cloth comprising resistance heating means and at least one integrated electrode for conducting electric current to said resistance heating means, characterized in that said textile product further comprises at least one additional electrode, said additional electrode being in electrical contact with said integrated electrode at at least two junction points.

2. A heatable textile product as in claim 1 , said textile cloth further comprising a second integrated electrode, said textile product comprises at least a second additional electrode, said second additional electrode being in electrical contact with said second integrated electrode at at least two additional junction points.

3. A heatable textile product as in any one of claims 1 to 2, wherein the distance between said junction points or between said additional junction points is smaller than or equal to 3 times the distance between adjacent resistance heating means.

4. A heatable textile product as in any one of claims 1 to 3, wherein Ra is less than or equal to Ri/20, said Ra being the linear resistance of said additional electrode, said Ri being the linear resistance of said integrated electrode, Ra and Ri expressed in Ω/m.

5. A heatable textile product as in any one of claims 1 to 4, wherein the linear electric resistance of said additional electrode is less than 1 Ω/m.

6. A heatable textile product as in any one of claims 1 to 5, wherein said integrated electrode comprises carbon or metal fibers.

7. A heatable textile product as in any one of claims 1 to 6, said additional electrode being a woven tape comprising metal wires, metal fibers or metallic coated fibers.

8. A heatable textile product as in any one of claims 1 to 7, wherein said electrical contact between said additional electrode and said integrated electrode is provided by using press-studs or rivets.

9. A heatable textile product as in any one of claims 1 to 7, wherein said electrical contact between said additional electrode and said integrated electrode is provided by stitching, welding, gluing or soldering said additional electrode to said integrated electrode.

10. A heatable textile product as in any one of claims 1 to 9, wherein said additional electrode and said integrated electrode are essentially parallel to each other.

1 1. The use of a heatable textile product as in one of the preceding claims as a heatable blanket or a heatable mattress coverage, or as a part of such heatable blanket or heatable mattress coverage.