FR2922405A1 - Textile heating structure for e.g. car seat, has resistive threads connected by conductive warp threads and releasing heat by Joule effect, where conductive threads are integrated in fabric weave during fabrication - Google Patents

Abstract

The structure has resistive threads (303) for releasing heat by Joule effect. The resistive threads are connected in warp, weft or selvedge by conductive warp threads (304) of low resistance. The conductive threads are integrated in a fabric weave during fabrication. Filling threads are made of polyester, cotton or polyamide/silver and integrated in the structure for ensuring mechanical resistance and non fire character.

Description

HEATING ARMORS 5 FIELD OF THE INVENTION

The invention relates to a knitted or woven textile structure for releasing heat during use of the product. The products can be used in various fields such as clothing (professional clothing, sports ...), furniture 10 (car seats, curtains ...), medical equipment (orthoses, lumbar belts ...). ), packaging, geotextiles (road antifreeze, road or airstrip, heating in the ground ...). It may also be technical uses such as heating or temperature maintenance material for pipes or various fluid lines, the protection of mechanical and electronic elements against low temperatures (defrosting aircraft), the heating of coating solutions or glue ... This list is not exhaustive; the application of the invention is also envisaged in all the fields where diffusion / convection of heat is sought by exposing the object or by wrapping a part of a living or inert body. PRIOR STATE OF THE ART

It has already been made more or less flexible materials, more or less modelable on a form, to provide thermal protection or ability to heat by providing a heat source Joule effect.

These materials are generally made by integrating, in a heterogeneous structure, often multilayer, electrical resistances in the form of resistive son traversing the structure. More recently, other textiles have been coated with a conductive substance.

This solution has the following disadvantages: • concentrating the heat emission around the resistors, • making the assembly more rigid, • almost always losing the elasticity that can be obtained by a textile.

The heat is not uniformly distributed throughout the textile surface and the temperature rises as you are close to the wire. It is then often necessary to use a second layer of textile avoiding contact between the hot spot and the body to

heat. The conductive wire is often composed of more rigid metal elements, which reduces the flexibility of the textile. The addition of metal son to a textile significantly decreases the flexibility and expandability of the latter.

The problem of the connection also arises for these fabrics which must be connected to a source of energy (transformer, battery or other). • Either they are connected at one point which does not ensure a uniform distribution of the electric intensity and this causes the appearance of warmer zones than others presenting sometimes even risks of hot spots (burn, fire). It is clearly shown by thermography that the heat emission is not homogeneous. • Either they are connected by mechanical or wire elements of low resistance, reported on the structure, and which distribute the electrical intensity (braid, plate).

In all cases, this brings rigidity to the final product (loss of flexibility in the connections), an increase in volume (thickness, due to the folds of the fabric on itself and seams). These solutions also require additional implementation work that increases the cost significantly.

SUMMARY OF THE INVENTION The invention provides a novel solution for homogenizing the heat and maintaining the flexibility and elasticity of the textile support.

The invention relates to a textile structure made of weaving or chain-knit technology or Rachel. The structure is composed of several types of yarns or fibers used simultaneously, some of which may be insulating and others resistant. The textile therefore has a heating resistance by Joule effect.

The invention resides in the insertion of the connector wire into the same reinforcement of the textile: A wire of a different and very significantly more conductive nature is introduced into the same weave of the fabric and provides the connection to the energy source. . The distribution of the electrical intensity of the current is then made very homogeneously thanks to a very good contact between the connection wire and the resistive wire. This conductive wire evenly distributes the electrical intensity in all the resistive wires; it follows that the heating is very homogeneous over the entire surface of the textile.

Indeed, the heating textile can be likened to a resistance network as shown in FIG. A.20

The desired resistances R make the textile heating by Joule effect. The resistors kR correspond to the linear resistances of the wire or connection systems. These resistances can disturb the homogeneity of heat diffusion. On the other hand, they must be minimized in order to limit unnecessary losses.

The power generated by each band and the connecting wires can be calculated by the basic electrical laws. It will be demonstrated on a three-band model, but it can be generalized to a larger number of bands or a continuous textile Calculations on this network of resistors show that the value of the resistance kR must not exceed 1 / 100th resistance R, otherwise the three bands no longer heat to equivalent power and there is formation of hot spots on the power connections. This modeling demonstrates the interest of having a highly conductive wire distributing the electrical intensity in the textile The demonstration can be carried to any number of heating strips, or even to a resistant textile, and therefore heated over its entire surface. The conductive wire is introduced in full or partial frame jetty mesh technology (Chain or Rachel) or weaving. It can also be warp knit or stitch knit technology in various weaves. These son son will be introduced with a spacing corresponding to the size of the article to achieve through electronic programming or with a submultiple lower step exact or approximate size of the article to achieve. It may also be introduced in the form of one or more woven selvedge yarns. Here too, a weaker step may possibly be retained by introducing chain conductor son in a regular spacing. There is thus no need for additional operation to integrate the connectors and the conductive wire is not on the surface (reduction of overthickness or risk of snagging) 25 since it is inserted into the weave of the fabric.

Moreover, it has been found that the resistive textile threads are not always homogeneous when their strength makes it difficult to reproduce the articles. Measurements of resistance can be observed along the wire of up to 3 to 20 times the average value. The capability of these yarn manufacturing processes is often low. These resistance peaks can induce localized overheating points or the cancellation of electrical current in the branch if other resistive wires are in parallel. As shown in Figure B, it is then possible to bypass the peak resistance by placing highly conductive son, which play the role of equipotential lines. A resistor network is then made with more points connecting the resistors, which allows a better distribution of the electrical intensity and therefore the thermal power.

In conclusion, the insertion into the textile of the connecting wire (connecting the heating wires to the energy source) therefore allows:

• homogenize the heat dissipation, • facilitate the connection to the power source without over-thickness, loss of flexibility, risk of snagging • reduce the risk of localized overheating points, • avoid the additional cost additional fabrication steps, • allow the use of a less efficient resistive wire (resistance variation) by creating intermediate equipotentials

DESCRIPTION OF THE DRAWINGS The manner in which the invention may be implemented and the advantages which result therefrom will emerge more clearly from the following exemplary embodiments, given by way of non-limiting indication in support of the appended figures. The thickness of the drawing lines is not representative of that of the threads used. Their distinction (thickness, dotted lines ...) simply allows a better differentiation of the threads for the understanding of the graphs. In addition, the dots are not to be confused with any armor (left / caught or under). Beyond the types of armor described, the invention is applicable with many armor selected according to the desired properties.

FIGS. 1 and 2 show two known methods of producing a flexible heating surface: • Material composed of several layers assembled by quilting for heating blankets for example, in which a resistive wire or cable is introduced. The heat diffusion is not homogeneous over the entire surface and the material loses its textile qualities of flexibility and possible elasticity. • Material composed of resistive son 202 introduced in the armor or covered with a resistive coating, but requiring a mode of surface connection brought to this material in the form of wire, braid or connecting bar 203, (seam, folds, clip ...) to obtain a distribution of the electrical intensity. • An alternative may be to make a point connection (for example with a snap) if resistive son are also introduced in a frame or in a knit, as shown in Figure 2a, but it is understandable then that the electrical intensity is not does not evenly distribute and that we will not obtain a homogeneous thermographic result.

Figure 3 is a schematic representation of the invention. This is a traditional woven structure, in which we find warp son 301 and weft son 302 arranged perpendicular to each other. Armor of

simple canvas is here made, but this principle is applicable with a more complex armor type twill, satin or jacquard, this list is not limiting.

The highly conductive weft thread 304 is inserted into the weave of the fabric. It connects the resistive son 303 and allows the connection to the energy source simply at both ends of the fabric. This keeps the flexibility and extensibility of the textile. Figure 3a illustrates an alternative with conductive weft son 304 arranged at a certain frequency to provide an intermediate distribution of electrical intensity or give flexibility of textile making.

Figure 4 illustrates an identical principle, but applied perpendicularly by installing the resistive son 403 weft and highly conductive son 404 at the edge of the textile. An alternative can be made with highly conductive warp yarns arranged at a certain frequency in the same way to provide cutting flexibility. This time, we keep the extensibility in the weft direction.

These two arrangements can also be combined with resistive son in warp and weft simultaneously.

FIG. 5 is a diagrammatic representation of a simple knitted structure of the halftone-chain type, in which we find wires in the warp direction 501 and 503 and others in the weft direction 502 and 504. The wire 504 is a very thin wire. copper-type conductor, connected to the power supply, which ensures the arrival of the current on the resistive son 503 which will emit heat by Joule effect. The son 502 are son inserted in weft which can be of various types depending on their function: they serve as a filling (type PES or PP for example), or to bring mechanical properties (aramid type). Figure 5bis highlights the quality of the contact made between the conductive wire and the heating wire which is meshed and thus clamped against the resistive wire providing a very good connection.

Note that other combinations are possible. Indeed, we can consider making the chain with a resistive wire for example. The choice of the son is left to the user according to the desired functionalities and the economic optimization of the realization.

FIG. 6 shows a knitted structure which differs from FIG. 5 in that the resistive wire is not inserted in a chain but is a partial frame. There are therefore the warp 601 and weft 602 son that form the matrix. The high resistivity wire 603 which brings the heating power, constitutes a partial frame. This weave also makes it possible to put the conductive thread in a chain at the ends of the fabric or according to

a repetitive step (fig 6bis). In fact, this arrangement also makes it possible for the conductive wire, which is much less resistant, to have a very good distribution of the intensity in the resistive wires which themselves form a homogeneous network of resistance in the weft direction.

The resistive wire 603 can thus form heating strips through the textile (FIG. 6 ter). Finally, the conduction wire 604 connecting the source to the resistors is inserted in a frame. It can be inserted either at the ends of the textile, or evenly through the fabric facilitating its cutting. It should be noted that the 603 wire pass is only an example and that many other possibilities are to be glimpsed.

Figure 7 shows a woven structure or a double needle-bedding. It can be a pocket cloth or other double needle armor. This creates a volume in the fabric, in which one can introduce the material to be heated, such as pipes or pipes. Any type of armor is conceivable if it respects the conditions imposed by a tissue structure pocket or double needle. In the example given, the wire 701 corresponds to the connection wire which has been placed at the ends, connected by heating wires 702 all held in the armor (or held by binding) by the wire 703.

DETAILED DESCRIPTION OF THE INVENTION

The invention consists in integrating highly conductive son in a heating textile armature, composed of heating son (a certain electrical resistance) and possibly also electrically insulating son. The insertion of the conductive threads into the same weave of the textile allows a perfect distribution of the distribution of heat by very uniform distribution of the electrical intensity which circulates in the different parts of the textile. The textile connections of the armor allow both an electrical contact of very good quality and the conservation of the characteristics of the flexible material.

The examples given below are not limiting but are intended to better identify the possibilities offered by this new technique.

We note in the invented object the presence of two or three types of son: 1. conductive son also called son of connection, which are the son connecting the energy source to the resistive heating son. These wires are generally made of conductive metal of copper, silver or any other highly conductive metal or alloy, for example Monel. These are single or multifilament metal son or gimped son of which one of the constituents is metallic (for example: a silver wrapping on a rubber core for both elastic and conductive properties). 2. Heating wires, which are resistivity wires of sufficient magnitude to produce a Joule-sensitive temperature rise. These yarns may be, for example, of polymer (polyamide, polyester, etc.) incorporating: coated or coated by any method (covering, coating or any other process) with a part of the order of one m of thickness , conductive metal (silver, stainless steel, copper ...). These son can also be son from a particular mixture (eg steel and stainless steel). 3. Finally, eventually, the son of binding or filling, are son that can be heterogeneous. We will choose either son for their low cost (polyester or other), or son for their touch (cotton, silk), or for their mechanical properties (aramids), or for their fungicidal and anti-bacterial properties. It will also be possible to use electrically insulating and thermally conductive wires in order to allow better heat transfer (for example silver polyamide wires).

The choice of these son of binding or filling depends on the other functionalities (excluding heating function) sought for the final application. The choice remains free, the only condition imposed is that they are weakly electrical conductor otherwise they must be analyzed in resistive son in the system. The various structures described below are therefore characterized by the fact that the three types of threads are an integral part of the reinforcement of the textile surface. Neither the conducting wires nor the heating wires are added to the surface of the textile; they do not need to be fixed in any way (heat-setting, sewing, folding, gluing or other). This avoids any loss of flexibility of the textile. This also avoids additional cost and manufacturing time.

The invention is a textile, which can be obtained on different types of textile machines. The armor can be very simple (canvas, satin) as very complex (jacquard fabric or even double fabric needle for example pocket type in order to use the drawing function or pocket for heating the material.

The wires are imperatively integrated in the armor. Their resistance will be mainly between 0.01 Ohm and 100 Ohms per linear meter. The resistance of these wires will be about 10 to 10,000 times lower than that of the heating wires so as to ensure a very good distribution of the electrical intensity throughout the textile structure by the heating wires.

The heating son form with possibly the binding son, most of the desired armor. Their resistance will be mainly between 50 Ohms and 20,000 Ohms per linear meter.

The filling or binding threads provide the complement of the armor to simply play a filling function or provide other functional characteristics.

These filler wires may also be selected for their thermal conductivity (eg silver polyamide) to promote perfect heat diffusion throughout the fabric.

The insertion of the conductive wire into contact with the heating wires, depending on the type of armor used, makes it possible in all cases to promote good contact between these two wires, which reduces the contact resistance, reduces the risk of hot spots, and promotes the homogeneity of the heating. This quality of contact ensures the uniformity of distribution of the intensity in the heating wires which being parallel, of length and therefore of equivalent resistance behave like resistors in parallel. The resistance of the conductive wires is negligible compared to that of the heating wires.

In the case of weaving, the connector wire is inserted into the weave: either in weft, or in a chain, or both directions. This insertion can be made either with an interval which corresponds to the ends of the final piece which will then be obtained by cutting the fabric, or with a sub-multiple step of the final dimension of this piece. In the latter case, a textile is obtained whose cutting will be all the more flexible and without loss of material in cutting that the pitch will be low. The regular insertion into the fabric 5 also favors the homogeneity of the heating by a better distribution of the electric current thus further reducing the points of overheating.

Another possibility is to insert the son of connectors in the edges of the fabric, for example for the large heating elements of heating blanket type or ground heating zone (airstrip or access path). They are then connected to the heating son and the base son, thus allowing the heating of the fabric, but the son of connectors are not present in the center of the textile surface, it still gains flexibility on the fabric.

The heating structure can also be derived from the Rachel type jet mesh technology or hook loom. In this technology, the possibilities are even more important:

Among all the possibilities of jersey weave, the following examples may be mentioned: a knit whose mesh yarn is a heating wire. Chain yarn is a filling thread replaced at the piece edge or with a sub-multiple step of the piece to be made by a highly conductive thread - a halftone chain made of binding thread (with specific properties if any) connecting the connecting wire (inserted in a chain), the heating wire (inserted in the chain direction), or vice versa. - A halftone chain where the binding yarn is the heating wire and where a non-conductive filler wire is inserted alternately in weft with a conductive wire at a certain frequency we can also consider that the wire inserted in a frame is a partial frame. It is possible to envisage inserting one or more layers of textile (woven, knitted, nonwoven or film) on which the son of connectors and heaters are deposited, and over which one knits, thus assembling the son of the heating system to a already existing flexible material. This type of assembly will be performed on a machine type Rachel with fleece insertion. The material obtained thus forms a multilayer providing a number of functionalities, for example impact resistance (bullet-proof vests or the like), puncture resistance or filtration of a geotextile, watertightness, thermal reverberation or simply homogeneous diffusion of heat. - you can also work in double needle. The interest is then to be able to heat the material, for example a cable or a duct, isolated from the others and with a larger contact area, the textile surrounding the object to be heated.

In both cases of weaving and knitting, we can play on the more or less repetitive distribution of the heating wire and wire connector at the armor. At the level of the textile surface, it is also possible to play on the continuous or repeated presence at regular intervals of heating wire strips. This allows us, during the manufacture of the fabric, to orient the textile towards a homogeneous heating, by pre-positioned strips to define the heating zones.

Claims (8)

: 1. Heating textile structure characterized in that the resistive heating son, ensuring a Joule effect heat release, are interconnected, in warp, weft or edge by one or more conductive son very significantly lower resistance, embedded in the weave itself of the fabric at the time of manufacture and without significant loss of flexibility of the textile. 2. Textile heating structure according to claim 1, characterized in that the conductive wire is introduced at the ends or in a repetitive manner, evenly or not in a warp or weft. 3. Textile heating structure according to claim 1, characterized in that it is carried out in weaving technology or mesh technology discarded type chain or Rachel or loom hooks. 4. Textile heating structure according to one of the preceding claims, characterized in that it consists of resistive heating son and brought into contact in the weave of the fabric at the time of manufacture of the fabric to lead son also constituting the armor whose linear resistance is significantly lower than that of the heating surface in a proportion of at least greater than 10. 5. Heating textile structure according to one of the preceding claims, characterized in that it also incorporates filling son typically made of polyester, cotton, polyamides to provide another function typically a mechanical strength or a non-fire character by example. 6. Textile heating structure according to claim 5, characterized in that the filler son are son selected for their good heat conduction (polyamide wire / Ag for example). These wires, then also weakly conductive, provide a guarantee of homogeneity of heating 7. Textile heating structure according to one of the preceding claims, characterized in that it is associated by Rachel fleece technology to a layer of a flexible material for example woven, knitted, non-woven or film. The resulting material thus forms a multilayer providing several functionalities and improved properties. 1140 8. Heating textile structure according to one of the preceding claims, characterized in that it is based on any weave more or less complex in weaving or knitting necessary properties sought elsewhere. The textile surface can for example be made of double needle bed making 3D textiles, giving directly a heating envelope.