Electric heating coil emitting only in half space.

Abstract

Electric heating coil emitting only in a half-space Electric heating by means of a winding of electrically heated ribbon and emitting heat essentially in its front part oriented towards the volume to be heated The said ribbon comprises two layers: one called support in insulating material or of low electrical conductivity and the other called electric in conductive material. The continuity of the electrical layer is interrupted locally in each half-turn not oriented towards the volume to be heated. The invention is particularly suitable for heating premises and more particularly for heating by infrared radiation. Figure to be published for the abstract: [Figure 1C]

Description

Title of the invention: Electric heating coil emitting only in a half-space.

[0001] FIELD OF THE INVENTION The present invention relates to a device for electrically heating premises by means of a winding of an electrically heated cord also called a resistive cord, i.e. having an electrical resistance suitable for being powered by an electric generator and emitting heat in its front part and not emitting heat in the rear part of the winding.

[0002] BACKGROUND OF THE INVENTION Heating premises using electrical energy essentially uses the Joule effect in an electrical resistive element powered by electrical connectors from an electrical energy source. The transfer of heat to the premises, the air and the occupants occurs by thermal conduction and / or convection and / or infrared radiation emitted by the electrical resistive element due to its temperature.

[0003] The electrical resistive element may be in the form of a winding (coil) of a resistive cord on a core, for example made of polymeric material for a resistive element intended to operate at low temperature or made of mineral material such as ceramic or glass for operation at higher temperature. The core may be, for example, cylindrical in shape with a director in the form of a circle or a very flattened ellipse or a polygon with rounded corners. The core can be a solid solid body or a hollow body, generally the resistive element has proximity and / or extensive contact with the mass of the core The core may be structured, for example comprising at its periphery longitudinal beams distributed radially regularly at the vertices of a polygon, thus enabling support of the ribbon through contact of the ribbon with the beams and the absence of contact of the ribbon with the core in the inter-beam spaces. The resistive cord may be, for example, but not limited to, a cylindrical section in the case of the winding of a conductive wire bearing an insulating varnish or, for example, a rectangular section in the case of the winding of a ribbon. In the latter case, we will speak of a heating ribbon. A heating coil heater may require a reflector located behind the coil, at a distance from it and of larger dimensions than the coil to reflect the radiation emitted towards the volume of the room. the rear by the rear part of the winding. Therefore, for a given dimensioning of the heating device, only a small part of the dimensioning corresponds to the radiation emitting surface, which implies choosing that the surface density of radiation emitted by the resistive heating element and therefore the temperature of the resistive heating element are high enough so that the total flow of power emitted is sufficient.

[0004] DETAILED DESCRIPTION OF THE INVENTION The device which is the subject of the invention presented below makes it possible to heat a room in particular by infrared radiation while avoiding the aforementioned drawback in the sense that it makes it possible to create a large heating surface emitting the power essentially towards the volume of the room, without the need for a thermal reflector at the rear of the heating element. The device which is the subject of the invention consists of at least one three-dimensional winding of a ribbon comprising at least one electrically continuous layer of an electrically conductive material capable of being powered by means of electrical connectors outside the scope of the invention, from a source of electrical energy outside the scope of the invention. A plane passing through the axis of the winding conventionally delimits two complementary parts of the winding. One part of said winding, called the lower part, is intended to be oriented towards the volume of the room and the other part, called the upper part, is intended to be oriented towards the ceiling or one of the walls of the room. The limits between the lower part and the upper part are conventionally called the left border and the right border. The device which is the subject of the invention is characterized in that: the tape is made up of two layers of two different materials joined together: a so-called support layer, made of electrically insulating material or of low electrical conductivity intended to ensure the mechanical properties, in particular strength to the tape. This layer can be a continuous or discontinuous structure such as a regular grid or a structure pierced with holes not regularly distributed a so-called electric layer made of electrically conductive material intended to ensure the circulation of an electric current throughout this layer and therefore to ensure the electric heating function.

[0005] As regards the support layer, low electrical conductivity means a choice of material and thickness of said layer such that the resistance per square inch (resistivity divided by the thickness) of the support layer is significantly higher than the resistance per square inch of the electrical layer, for example 10 times higher. As a non-limiting example, a 50 micron thick stainless steel support layer has a resistance per square 10 times greater than a layer 18 micron thick aluminum electric

[0006] The winding of the ribbon can be carried out so that the electrical layer is on the outside of the winding, the stacking of the two layers is then conventionally referred to as an external stack, or carried out so that the electrical layer is on the inside of the winding, the stacking of the two layers is then conventionally referred to as an internal stack.

[0007] An example of this type of tape consists of a support layer of polymeric material such as polypropylene or Teflon or polyethylene terephthalate (PET) or of low electrical conductivity metal such as stainless steel, 25 to 100 micrometers thick, typically 50 micrometers, and 10mm to 100mm wide, typically 25mm, and the electrical layer is made by depositing 0.5 micrometers thick aluminum on the surface of the support layer.

[0008] The parts of each turn included within the limits of the lower part of the winding, called the lower turn part, are electrically supplied in parallel by means of two equipotential connectors positioned one in the vicinity of the left border, the other in the vicinity of the right border and extending in the direction of the winding axis over all the turns and establishing electrical contact with each of the turns. The electrical layer of the parts of each turn included within the limits of the upper part of the winding, called the upper part of the turn, is locally removed so as to remove the electrical continuity of this layer, without altering the support layer, over a sufficient width, for example 1 mm, so that an electric current cannot circulate in this said upper part. This removal can be obtained for example by chemical etching in the case of an outer winding and an electrical layer made of aluminum or by vaporization under the effect of a laser beam, scanned over all the upper turns in a direction close to that of the axis of the winding or by cutting using a tool (cutter for example). In the case of an inner winding the same methods as for the outer winding can be applied to the ribbon before it is actually wound around the core.In the case of an internal winding it is also possible to eliminate the electrical continuity once the winding around the core is effective by vaporization of the electrical layer under the effect of a laser beam, the wavelength of which is chosen so as not to be absorbed when passing through the support layer, scanned over all the upper turns in a direction close to that of the axis of the winding. In this case the structure of the core will have been preferentially chosen so as to present a hollow under the electrical layer at the right of the path of passage of the laser beam.

[0009] Thus the upper portions of turns do not produce electrical power, so no heat. Only the lower portions of the turns produce heat. This avoids the need to use a reflector at the rear of the winding because there is no heat and / or radiation to return to the volume of the room. The shape of the turns is preferably oblong so that the winding has in its lower part a radiating surface of large extension while keeping a limited vertical dimension. In an exemplary embodiment known as a parallelepiped with rounded ends (figures IA to IC), each turn is inscribed on a volume consisting of a rectangular parallelepiped volume of large horizontal extension and much lower vertical height, two of the opposite vertical faces of which are each adjoining a semi-cylindrical volume of diameter equal to the height of said face. Each of the semi-cylindrical volumes is hollowed out along its length with a groove intended to each receive one of the two equipotential connectors. In another embodiment, each turn is inscribed on an ellipsoid with a major horizontal axis much larger than the minor vertical axis (figures 2A and 2B); for example, the major axis is ten times larger than the minor axis.

[0010] BRIEF DESCRIPTION OF THE DRAWINGS Other objects, characteristics and advantages of the invention will be better understood in light of the detailed description which follows, with reference to the appended drawings in which: Figures 1A to 1C represent an embodiment of the invention on a core (102) of parallelepiped type having two extended flat surfaces (1021) one of which is engraved with the hollow (1024), between two rounded ends (1022) each being engraved with a groove (1023) intended to be the housing of one of the two equipotential connectors (103) whose connection to the external electrical power supply circuit is not shown. [Fig.lA] shows the said core (102) with its two rounded ends (1022), the extended surface (1021) engraved with the hollow (1024), the two connector housings (1023) and the two equipotential connectors (103) positioned outside their housing (1023). [Fig.lB] is a section showing the upper half of the winding of the ribbon (101) without the presence of the core, thus making it possible to see from below the break (1013) in the continuity of the conductive layer (1011) secured to the support layer (1012). [Fig.lC] shows the entire winding of the ribbon (101) with its support layer (1012) and its electrical layer (1011) on the core (102) and the equipotential connectors (103), the break (1013) of continuity of the electrical layer and the hollow (1024)

[0011] Figures 2A and 2B show an embodiment of the invention where the section of the nucleus is of elongated elliptical shape. [Fig.2A] shows the elliptical cross-section core (202). [Fig.2B] depicts the flat ribbon (201) viewed from the top side of the winding as it appears once wound on the core (202) where the break (2013) in electrical continuity of the electrical layer (2011) on the support layer (2012) is seen. [Fig.2B] also shows the connectors (203) in contact with the electrical layer (2011)

Claims

Claims

1. Electric heating device consisting of at least one three-dimensional winding of a ribbon comprising an insulating or low electrical conductivity support layer and a layer of electrically conductive material called the electrical layer, on a core characterized in that: Each upper half-turn comprises a local interruption of the electrical layer over a distance sufficient for.interrupt the electrical continuity of the electrical layer of each upper half-turn The electrical layers of the lower half-turns are electrically supplied in parallel between two equipotential connectors extending outside the winding and in contact with all of the lower half-turns or extending inside the winding and in contact with all of the lower half-turns and establishing contact with them, and positioned in the vicinity of the boundaries between the upper part and the lower part of the winding and oriented substantially along the axis of the winding.

2. Claim according to 1 wherein the support layer is made of polymeric material

3.

4.

5. Claim according to 1 where the support layer is made of stainless steel Claim according to 1 to 3 where the electrical layer is made of aluminum Claim according to 1 to 4 where the width of the tape is between 10 mm and 100 mm and where its total thickness is between 25 micrometers and 100 micrometers.

6. Claim according to 1 to 5 where the core is of parallelepipedal shape with rounded edges

7.

8. Claim according to 1 to 5 where the core is of elongated elliptical shape. Claim according to 7 where the stack of the electrical layer and the support layer is of the outer type

9. Claim according to claim 7 where the stacking of the electrical layer and the support layer is of the interior type

10. Claim according to 9 wherein the connectors are inside the winding

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