EP1236819A1 - Electrically conductive fabric - Google Patents

Abstract

A fabric consists of a warp or weft containing groups of carbon filaments and groups of non-conducting filaments, the carbon filaments being in regularly-spaced strips (2) at set intervals (d). The weft or warp contains groups of metal and non-conducting filaments, the metal filaments being in strips (3) linking the carbon filaments in parallel and spaced regularly at intervals (D). <??>A fabric consists of a warp or weft containing groups of carbon filaments and groups of non-conducting filaments, the carbon filaments being in regularly-spaced strips (2) at set intervals (d). The weft or warp contains groups of metal and non-conducting filaments, the metal filaments being in strips (3) linking the carbon filaments in parallel and spaced regular at intervals (D) that are at least five times greater than the intervals between the carbon filaments. Both warp and weft filaments are coated on both sides with a layer of insulating material. The metal filaments are selected from nickel, aluminum, stainless steel and gold-plated filaments.

Description

Tehnique domain

The invention relates to the field of technical textiles, and more precisely to electrically conductive textiles. She finds applications multiple, and in particular in the production of truck tarpaulins, flexible roofing or even furnishing or interior fittings. It relates to more particularly a heating fabric incorporating metallic wires and carbon which allow heating by a “low voltage” power supply, and which is by construction very easily configurable to any geometry pattern, and to different surface heating powers.

Previous techniques

In known manner, electrically conductive textiles consist of a elementary support fabric incorporating in the warp and / or weft copper wires or more generally metal wires. The presence of these sons gives the tissue structure some electrical conductivity allowing for multiple uses, and in particular for constituting heating fabrics.

The objective of the invention is to provide a fabric which has properties electric and continuous on the surface of the fabric.

Many solutions have already been proposed to integrate such a thread conductor inside a fabric.

Thus, in the document FR 2 340 016, a conductive fabric has been described including among its weft threads, electrically conductive threads. These sons of frame are electrically connected in parallel by two conductive chain wires located on each side of the fabric.

It is understood that this kind of fabric has a number of drawbacks. When you want to make fabrics with sufficient width, it is necessary to subject the weft threads to a relatively tension important, generally equal to the 220 volts AC mains voltage. employment such a voltage poses electrical safety problems, and in particular in that which concerns the risks of contact by people. This electrical voltage important is also necessary given the poor connections existing between the electrode chain son, and the conductive weft son.

Another example of such a fabric has also been described in the document FR 2 263 658. In this case, the paralleling of the various conducting wires is made by the use of a copper strip placed in the edges of the fabric. The use of these strips has two major drawbacks. On the one hand, such copper strips are relatively rigid and prevent the fabric from conforming very simply. On the other hand, the connection between the strip and the conductive wires is relatively poor, and therefore requires the use of a high voltage, that is to say in practice the network voltage 220 volts, inducing a very weak current more compatible with such a connection quality. The disadvantages of the job of a high voltage are the same as those indicated above.

In addition, the power dissipated per unit area, for a fabric of given dimensions, is only a function of the applied voltage. In others terms, it is not possible to adapt the dissipated power according to the desired application.

The objective of the present invention is to provide a conductive fabric which can be used with supply voltages of the "low voltage" type, that is to say, included in the conventional range from 12 volts to 48 volts. A another objective is to allow a great modularity so as to ensure a energy dissipation per unit area which is user configurable very easy way.

Another objective is to provide a coated fabric whose coating does not disturb not the connection properties between the conductive wires.

Statement of the invention

The invention therefore relates to a fabric which has conduction properties. electricity.

dans le sens chaíne ou trame, des groupes de fils de carbone et des groupes de fils non conducteurs de l'électricité, lesdits groupes de fils de carbone formant des bandes régulièrement espacées d'une distance d ;

dans le sens trame ou chaíne, des groupes de fils métalliques et des groupes de fils non conducteurs de l'électricité, lesdits groupes de fils métalliques formant des rayures reliant électriquement en parallèle les groupes de fils de carbone entre eux, les rayures de fils métalliques étant régulièrement espacées d'une distance D au moins cinq fois supérieure à la distance d ;

une couche de revêtement isolant recouvrant chaque face du tissu.

Such a fabric is characterized in that it comprises

in the warp or weft direction, groups of carbon wires and groups of non-electrically conductive wires, said groups of carbon wires forming bands regularly spaced apart by a distance d;

in the weft or warp direction, groups of metallic wires and groups of non-electrically conductive wires, said groups of metallic wires forming stripes electrically connecting in parallel the groups of carbon threads together, the stripes of metallic threads being regularly spaced by a distance D at least five times greater than the distance d;

an insulating coating layer covering each side of the fabric.

In other words, this fabric comprises, arranged in a regular manner, strips of carbon threads which ensure energy dissipation when traversed by an electric current. These strips of carbon threads are connected together by strips of conductive wires such as metallic wires, strips of wires of metal serving as supply and current leads to the carbon threads. These strips of power wires are much more spaced apart from each other as strips of carbon threads.

By using two materials of markedly different conductivity, i.e. carbon wires having a resistivity markedly higher than that of the wires metallic, most of the voltage drop takes place across the carbon wires, which therefore provide a much higher energy dissipation than that which has place in the transverse metal wires.

The weaving of the different threads of the carbon thread strip with the threads metallic wire strip provides relatively contact important between these different wires, and therefore a connection that allows the passage of an important current, and therefore the use of the fabric in association with low voltage power supplies, from 12 volts to 48 volts.

In addition, the distribution of metallic wires and carbon wires on the entire surface of the fabric gives it a matrix structure thanks to which it is possible to supply voltage to any length or fabric width, if this width or length is greater than the distance D separating the strips of metal wires.

In other words, the supply wires are sufficiently numerous throughout the width of the fabric to form two electrodes for any cut tissue.

Due to the weaving of metallic and carbon threads, the pressure exerted on the contact area between these different wires is sufficient to withstand the pressure of the plastic which is used during the coating operation of the tissue.

In practice, the metallic wires used can be alloy-based wires nickel, aluminum wires, stainless steel wires, or wires covered with a layer of gold.

We prefer for example to use nickel alloys for its good compatibility with the connectors generally carried out with alloys of copper. Given the very small number of metallic supply wires, the use of relatively expensive materials increases almost insensitively the cost price of the fabric according to the invention. We will therefore favor the very good conductive qualities of certain relatively expensive metals.

Furthermore, the non-conductive wires used between the metallic wires can advantageously be polyester yarns, used for their good behavior mechanical.

Other metals can also be used if their resistivity is sufficiently low, compared with that of the carbon heating wires, and in taking into account the relationship between the distances d and D separating the different bands carbon wires and metallic power wires.

In a particular form, the coating layers, and for example coating, covering the two sides of the fabric may be different.

In this way, we ensure a dissipation of energy which is different from a facing the other side of the fabric, which helps direct the heat flow in a privileged direction. In practice, we choose coating layers that have different thermal properties, for example using fillers in different proportions from one side to the other.

Advantageously in practice, the distance d separating the strips of wires from carbon can be between 1 and 10 centimeters, the distance separating the metal wire bands then being between 20 centimeters and 2 meters.

Thanks to these dimensions given for information and not limitation, it is possible to cut the fabric while retaining the possibility of feeding whatever whatever the general shape of the cut, as soon as it is greater than the dimension D separating the stripes of metal wires.

In practice, power can be obtained by connecting different bands of wires alternately at one of the two terminals of the power source electric.

According to another characteristic of the invention, the fabric can have on its selvedges, and at the ends of the strips of metal wire, areas in which the coating layers are removed. In this way, by performing a cutting perpendicular to the metal wire strips, at the level of the latter, just extract the coating layers by sliding them around the wires by pulling them out of the fabric. We do the same so that we strip a sheathed metal wire by stripping the extremal zone of the strip of metal wire.

It follows that all of the metal wires thus stripped can be assembled to be then placed in supply terminals arranged on the edges of the fabric.

These supply terminals can be arranged at the end of all or part of the metal terminals, depending on the supply voltage that wish to apply to the fabric.

Thus, by varying the number of strips of metal wires present between two power supply terminals, the power dissipated per unit is varied surface, which allows the fabric to be adapted to different applications.

Brief description of the figures

La figure 1 est une vue schématique d'un tissu conforme à l'invention.

La figure 2 est une vue en coupe de détail illustrant le tissage des fils de carbone et des fils métalliques.

La figure 3 est une vue en perspective sommaire d'une lisière du tissu conforme à l'invention, pendant la réalisation d'une connexion latérale.

La figure 4 illustre une étape ultérieure de celle de la figure 3.

La figure 5 est une vue schématique illustrant les différentes possibilités d'alimentation d'un dispositif conforme à l'invention.

The manner of carrying out the invention as well as the advantages which result therefrom will emerge clearly from the description of the embodiment which follows, given by way of nonlimiting example, in support of the appended figures in which:

Figure 1 is a schematic view of a fabric according to the invention.

Figure 2 is a detail sectional view illustrating the weaving of carbon threads and metallic threads.

Figure 3 is a summary perspective view of an edge of the fabric according to the invention, during the production of a lateral connection.

FIG. 4 illustrates a subsequent step from that of FIG. 3.

Figure 5 is a schematic view illustrating the different possibilities of supplying a device according to the invention.

Way of realizing the invention

As already mentioned, the invention relates to a heating textile which is produced by weaving, and which incorporates two different types of conductive threads in these directions a chain and a frame.

Thus, and as illustrated in the example of FIG. 1, the fabric (1) comprises strips (2) of carbon threads which are spaced apart by a distance d. This fabric (1) also includes strips (3) of metal wires.

In the example illustrated, the carbon threads have a titer of 200 tex and have 200 fibers per thread. Each strip (2) comprises five carbon threads of this guy. The strips (2) of carbon threads are spaced by a distance d of 5 centimeters.

In an alternative embodiment, the carbon wires can be replaced by wires with similar electrical properties, i.e. higher resistivity to the supply wires. Mention may for example be made of threads made from fibers metal, with a diameter of the order of a micrometer.

In the example of FIG. 1, the metal wires used are the wires of pure nickel twenty hundredths of a millimeter in diameter. Each strip (3) of wire metal includes ten nickel wires, which represents a bandwidth of the order of the centimeter.

The strips (3) of metal wires are spaced apart by a distance D equal to about a meter.

Considering the fact that the resistivity of nickel is about a hundred times lower to that of carbon, the voltage drop measured along the supply wires of a strip (3) is negligible with regard to the voltage drop measured along copper wires between two successive bands (3).

It is this last drop in voltage which causes the wires of the copper and the dissipation of energy sought.

The threads (4) used for the rest of the fabric are non-conductive threads, for example example of conventional high tenacity polyester yarns of 1100 dtex, 200 strands.

Of course, the values and materials given above are by way of example only, and the invention covers multiple variants of deviating from it.

The weaving of metallic threads (13, 14) with carbon threads (12) such as illustrated in FIG. 2, provides an advantage as regards the surface of contact between these different wires. Indeed, the contact area between the carbon wires (12) and the metal wires (13) extends over part of the circumference of the wires carbon (13), typically greater than a quarter of this circumference. The sons of carbon which are more flexible than the metallic wires tend to crush, this which considerably increases the contact surface.

This large contact surface allows the passage of a current relatively high, such as those used for low voltage power supplies of the type 12 to 48 volts.

In FIG. 2, the presence of the coating layer (15, 16) which covers both sides of the fabric, thus preventing any risk of contact with live areas. In the illustrated form, the coating layers (15, 16) are identical and made for example of PVC. However, as already mentioned, these layers (15, 16) can be different so as to influence the direction of the heat flow released by the carbon wires (12).

By way of example, when the textile according to the invention is used as that top cover of a building, and that it is intended to ensure a melting snow control, we will favor the heat flow towards the upper face of the tissue. In this case, the coating layer (15) located on the upper side of the fabric has better thermal conductivity than the layer (16) located on the lower side.

Likewise, the coating used may be such that its conduction properties heat varies on the very surface of one side of the fabric. So by modulating this thermal conductivity, we can standardize the heat flow emitted between the zones comprising the carbon threads, and the spaces between these strips of carbon.

Another characteristic of the invention relates to the ease with which the fabric according to the invention can be connected to the power supply. Figures 3 and 4 illustrate the manipulations necessary to ensure the connection of the tissue to a power source.

Thus, the fabric (1) has on its selvedge (5) different weft threads which are visible through the coating layer (15). Among these apparent sons, one identifies nonconductive polyester yarns (6) and metallic yarns (13). These metallic wires (13) are part of a strip (3) of conductive wires. After having proceeded to a notch of the fabric along the planes (20, 21) parallel to the weft, we have cut the polyester chain threads (4) located in this region.

We then proceed to a slight notch (22) parallel to the chain son to delimit the area which will then be extracted. This notch (22) can be made by an appropriate tool or even not be physically materialized, but simply result from the traction which will be carried out by the operator.

Thereafter, the operator pulls on the area delimited by the cutouts (20, 21, 22). This zone (25) slides on the metal wires (13), which is then extracted as in figure 4. This zone contains the portions of wires of polyester (4) which were previously cut when making the notches (20, 21). The various metallic wires (13) are then visible at the edge of the fabric, and the operator just has to put them together to put them in place in the appropriate connectors. The connection of the strip (3) of metal wires (13) is thus assured.

Of course, the operator chooses according to the configuration of the fabric and the tension supply the strips (3) which must be thus stripped.

Thus, different power configurations can be used.

Thus, as illustrated in FIG. Sa, the power source (26) can see its upper terminal connected to the terminals of the metal wires (3a, 3c, 3e), while its lower terminal is connected to the bands (3b, 3d). In other words, all segments of carbon wires located between two strips (3) of metal wires are subjected to the source supply voltage (26).

In the other configuration illustrated in FIG. 5b, the power source (27) has its upper terminal connected to the bands (3a, 3e) of the fabric, while its lower terminal is connected to the strip (3c) of the fabric. In this case, and at voltage constant supply, the carbon wire segments are subjected to potential difference equal to half that of the previous configuration.

It follows that the heat given off by the surface unit is equal to a quarter of that which is dissipated in the case of the configuration of the power source (26).

The same logic can be applied with the configuration of the source supply (28) illustrated in Figure 5c. In this case, the power source (28) is connected by its positive terminal to the band (3a) and its negative terminal to the band (3e). From an equivalent source, the tension imposed on the carbon wires is worth a quarter of that of configuration (26), which results in a power dissipated sixteen times lower.

Of course, the wiring diagram of the different metal strips (3) can be adapted according to the desired dissipation power, in determining the length of the carbon threads required, and therefore the multiple of the distance D to obtain the dissipation of the desired power.

This wiring can also be variable inside the fabric, to focus energy dissipation in specific areas.

In the same way, this wiring can be adapted according to the voltage nominal of the sources (26-28) used.

Thus, by way of example, for a power to be dissipated of the order of 100 watts per square meter, a supply voltage of 12 volts may be sufficient. It's about then applications allowing a slight warming of the fabric in order to elimination of the condensation present on it when used for make marquee tents or other similar constructions.

For a wiring diagram, a 24 volt supply will quadruple the dissipated power per unit area. So, with 400 watt dissipation per square meter, the fabric can be used to make roofs or hangings superior able to withstand snow. In this case, the heating will allow to ensure a slight melting of the snow. This merger will be controlled, so that water accumulations will be avoided when the snow melts, thanks to a control the areas in which the snow will melt first.

When the same layout design is used with a source 48 volt power supply, therefore corresponds to a dissipation of 1600 watts per square meter, the fabric can then be used for heating applications, for example example for forming heated partitions or ceilings.

la possibilité d'être alimenté de façon tout à fait sûre par des alimentations basses tension, du type 12 à 48 volts ;

une très grande modularité du fait de sa structure matricielle, qui permet d'obtenir les propriétés recherchées quelle que soit la forme des découpes du tissu ;

une grande facilité pour réaliser la connectique aux sources d'alimentation électrique.

It appears from the above that the fabric according to the invention has multiple advantages and in particular:

the possibility of being supplied in a completely safe manner by low voltage power supplies, of the 12 to 48 volt type;

a very high modularity due to its matrix structure, which makes it possible to obtain the desired properties whatever the shape of the cutouts of the fabric;

great ease in making the connections to the power sources.

Industrial applications

The fabric according to the invention has multiple applications thanks to on the one hand to its matrix structure, on the other hand to its great ease of connection.

Thus, this fabric can be used for multiple heating applications, in particular exterior walls of a building, as well as interior walls of the partition type or other. It can also be used for heating functions in all kinds of articles suitable for being covered with a textile. It can also be accessories used in the home such as blinds.

Thanks to its excellent electrical qualities, this fabric can also be used for anti-static applications, and especially in areas where it is necessary to perform dust extraction such as industries mining, or automotive or railway tunnels, or even in the electronics industry.

It can also be used to equip buildings so that they confer Faraday cage properties.

Claims (8)

Fabric (1) having electrical conduction properties, characterized in that it comprises: in the warp or weft direction, groups of carbon wires (12) and groups of wires (4) which are not electrically conductive, the said groups of carbon wires forming bands (2) regularly spaced apart by a distance d; in the weft or warp direction, groups of metallic wires (13) and groups of non-electrically conductive wires, said groups of metallic wires forming bands (3) electrically connecting in parallel the bands (2) of son of carbon between them, the strips (3) of metal wires being regularly spaced by a distance D at least five times greater than the distance d; an insulating coating layer (15, 16) covering each side of the fabric. Fabric according to claim 1, characterized in that the metallic threads (13) are chosen from nickel threads, aluminum threads, stainless steel threads and threads covered with a layer of gold. Fabric according to claim 1, characterized in that the son (14) not electrically conductive are polyester son. Fabric according to claim 1, characterized in that the layers of insulating coating (15, 16) are layers obtained by coating. Fabric according to claim 1, characterized in that the layers of insulating coating (15, 16) are different on the two sides of the fabric. Fabric according to claim 1, characterized in that the distance d separating the strips (2) of carbon threads is between 1 and 10 centimeters, and in that the distance D separating the strips (3) of metallic threads is between 20 centimeters and 2 meters. Fabric according to claim 1, characterized in that it has on its edges (5), and at the end of the strips (3) of metal wires, zones (25) in which the coating layers (15 , 16) are eliminated. Fabric according to claim 1, characterized in that it further comprises supply terminals arranged on its selvedges, at the end of certain groups of metallic threads.

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