HEATING COIL OPTIMIZED FOR HALF SPACE.

Abstract

TITLE OF THE INVENTION: ELECTRICAL HEATING RESISTANCE EMITTING 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. Said ribbon comprises two layers: one called support in insulating material or with low electrical conductivity and the other called electrical in conductive material. The continuity of the electrical layer is interrupted 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 1B]

Description

Title of the invention: HEATING COIL OPTIMIZED FOR 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 ceramic. 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 at the rear of the coil, at a distance from it and of larger dimensions than the coil to reflect back into the volume of the room the radiation emitted towards the rear by the rear part of the coil. Therefore, for a given sizing of the heating device, only one 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. An example of a heating cord winding is a winding of a circular cupro-nickel wire section of 1 mm in diameter with a pitch of 2 mm. Another example of a resistive cord winding is a winding of a stainless steel or aluminum alloy ribbon where the width of the ribbon is between 25 mm and 50 mm, typically having the value of 30 mm, and where its thickness is between 15 micrometers and 100 micrometers, typically having the value of 20 micrometers with a pitch of 35 mm. Another example of a resistive cord winding is a ribbon of polymeric material such as, for example, polypropylene or PET or Teflon, 50 micrometers thick and 25 mm wide, aluminized on at least one of its faces to a thickness of 5 micrometers.

[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 N turns 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.

[0005] The device which is the subject of the invention is characterized in that: The parts of each turn included within the limits of the lower part of the winding, called lower turn parts, are electrically supplied by means of two connector assemblies positioned one in the vicinity of the left boundary, the other in the vicinity of the right boundary and extending in the direction of the winding axis over the set of turns and establishing electrical contact with each of the turns where each connector assembly has the function of allowing the circulation of electric current in the set of lower turn parts according to two options: Series-ZigZAG option where the current follows a zig-zag path between the entry point which is located at the first turn and the exit point which is located at the last turn or vice versa if the direction of the current is reversed Parallel option the lower parts of the coils are electrically paralleled

[0006] To achieve the Zig Zag Series option Each of the connector assemblies is composed of two separate assemblies of two types of elements, connecting elements and interface elements, electrically isolated from each other providing An input interface element is located opposite the first turn and establishes electrical contact with this first turn and only with this first turn. This interface element is electrically connected to one of the poles of the external electrical generator intended to supply the electrical power. Only one other element is of the output interface type, is located opposite the last turn, and establishes electrical contact with this last turn and only with this last turn. In the case where the number of turns is odd, the output interface type element is not on the same connector assembly as the input interface type element

[0007] - the other elements of each connector assembly, other than the input interface element and output interface, are of the connection type, and each establishes the equipotential contact with the two turns of each of the pairs of two consecutive turns

[0008] In a preferred embodiment of the connector assemblies, the interface and connection elements are in tubular form and are supported by a common axis made of insulating material, polymeric for operation at low temperature or mineral such as ceramic or glass for operation at higher temperatures. The electrical layer of the parts of each turn included within the limits of the upper part of the winding, called the upper turn part, 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 flow in this said upper part. An element of the connector assembly is of the input interface type, is located opposite the first turn, and establishes electrical contact with this first turn and only with this first turn. This interface element is electrically connected to one of the poles of the external electrical generator intended to supply the electrical power. Only one other element is of the output interface type, is located opposite the last turn, and establishes electrical contact with this last turn and only with this last turn spire. In the case where the number of turns is odd, the output interface type element is not on the same connector assembly as the input interface type element.

[0009] - the other elements of each connector assembly, other than the input interface and output interface element, are of the connection type, and establish equipotential contact with the turns of each of the pairs of two consecutive turns In a preferred embodiment of the connector assemblies, the interface and connecting elements are in tubular form and are supported by a common axis made of insulating material, polymeric for operation at low temperature or mineral such as ceramic or glass for operation at higher temperatures.

[0010] -To achieve the Parallel option, each connector assembly is an equipotential structure, having a contact surface with each of the turns at least at the level of their lower part and located in the vicinity of the left border for one and the right border for the other.

[0011] The part of each turn included within the limits of the upper part of the winding, called the upper part of the turn, is in contact and secured to the surface called the fixing surface of a part called the fixing part over at least part of the width of the cord and over a length at least equal to the width of the cord where the fixing part is secured to the core, possibly monolithically, or is supported by the core while maintaining at least one degree of freedom in the longitudinal direction relative to the core.

[0012] The joining can be obtained by gluing, the cord can be pre-coated before winding and or the surface of the fixing part is pre-coated with glue. The connection of the cord to the fixing part can be obtained by spot or laser welding of the tape onto pairs of metal studs inserted into the fixing part, flush with the surface and arranged so as to be under the path of each turn of the heating cord and without any possible overflow of the latter allowing contact with the neighboring turns.

[0013] The connection can be obtained mechanically by generating friction forces between the cord and the fixing part, for example through two support plates exerting pressure on the cord with sufficient force on either side of an uncompressed space intended to correspond to the suppression zone. These two support plates can be, for example, screwed and / or stapled and / or nailed onto the fixing part. The electrical continuity of the upper part of the coil is locally suppressed in a so-called suppression zone over a sufficient distance, but significantly smaller than the length of the contact and fixing surface, for example 50 microns, so that an electric current cannot flow in this said upper part. The suppression of said electrical continuity can be obtained either by making the suppression zone non-conductive, for example by local oxidation by locally heating this zone under an oxygen atmosphere with a laser, or by ablation of the material of the bead in this zone. This suppression zone is located inside the contact and fixing surface, preferably towards the middle of the contact and fixing surface. In the event of the choice of welding on pairs of metal pads, the suppression zone passes between the two pads of each pair. The performance of the suppression step must only take place once the joining step is effective.The removal of the material of the cord in the suppression zone can be obtained for example by chemical etching in the case of an aluminum ribbon 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 cutting tool for example a cutter.

[0014] Thus the upper portions of turns do not produce electrical power, therefore no heat. Only the lower portions of turns produce heat. This avoids the need to use a reflector at the rear of the winding as there is no heat and / or radiation to be returned 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 shape (figures 1A and 1B), 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 a concave hemicylindrical surface of diameter substantially equal to the height of said face, intended to be a housing for one of the two connector assemblies. In another example of 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.

[0015] 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 and 1B represent an embodiment of the invention on a core (102) of parallelepiped type having two extended flat surfaces (1021) which are set back from the ribbon cord stretched between the two connector assemblies, one of which has a hollow intended to accommodate the fixing part (1025) whose surface (1024) is intended to come into contact with the ribbon cord to fix it by gluing, between two concave rounded ends (1022) each intended to be the housing of one of the two connector assemblies (103) whose connection to the external power supply electrical circuit is not shown. [Fig.lA] shows the said core (102) with its two concave rounded ends (1022), the extended surfaces (1021) with the hollow on one of the surfaces receiving the fixing part (1025), and the two connector assemblies (103) positioned outside their housing (1022). There we can see the interface elements (1031), the connecting elements (1032) as well as the spaces (1033) for electrical insulation between the various elements and the axis (1034) on which all the elements are installed. [Fig.lB] shows in 3D view and in section the entire winding of the ribbon (101) on the core (102) and the connector assemblies (103), the hollow receiving the fixing part (1025) having the surface (1024) with pre-gluing for contact and fixing and the break (1013) of continuity of the ribbon cord positioned substantially in the middle of the surface with pre-gluing of the fixing part.

[0016] Figures 2A and 2B show an embodiment of the invention where the core section is of elongated elliptical shape. [Fig.2A] shows the winding seen from the upper side just after the winding operation on the core (202) and before the operation of creating the break in continuity has been carried out. We see the pre-glued surface (204) intended to fix the turns of the winding. We also see the two connector assemblies (203) positioned at a distance from the winding. We can see an adaptation surface (2035) shaped to the shape of the ribbon cord. [Fig.2B] shows the winding seen from the upper side and the view of the winding seen from the lower side. From the upper side, the flat ribbon cord (201) is seen as it appears once wound on the core (202) and once the operation of creating the break in continuity has been carried out, where the pre-glued surface (204) intended to fix the turns of the winding is seen, the break (2013) in electrical continuity of the ribbon cord (201) located substantially in the middle of the pre-glued fixing zone (204). [Fig.2B] also shows the connector assemblies (203) in contact with the ribbon cord (201).

Claims

Claims

1. Electric heating device consisting of at least one winding of N turns, three-dimensional of an electric heating cord preferably in the form of a strip, on a core characterized in that: - each upper half-turn of the heating cord is secured on the surface called the fixing zone of a so-called fixing part, secured to the core or having at least one degree of freedom in the longitudinal direction relative to the core - the electrical continuity of each upper half-turn is interrupted, either by ablation of the material or by conversion of the conductive material into insulating material, locally over a distance called the interruption zone,the said interruption zone is located between the limits of the fixing zone - two connector sets are located in contact with the heating electric cord and positioned in the vicinity of the left and right borders between the upper part and the lower part and have the function of establishing the electrical connection between the heating cord and the external power supply circuit.,

2. Claim according to 1 where each of the connector assemblies is composed of two separate assemblies of two types of elements, connecting elements and interface elements, electrically insulated from each other which ensure: By the connecting elements, the connection of the electrical layer to the external electrical circuit at the level of the first turn and the last turn By the interface elements, the equipotential connection between the two turns of each pair of consecutive turns thus allowing a Zig-Zag circulation of the current in all the lower parts of the turns

3. Claim according to 1 where each connector assembly is equipotential and the lower half-turns are supplied in parallel.

4. Claim according to 1 to 3 where the cord is a stainless steel or aluminum ribbon, or made of a ribbon of insulating material or of very low conductivity covered with a conductive layer.

5. Claim according 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 concave hemi-cylindrical edges

7.

8. Claim according to 1 to 5 wherein the core is of elongated elliptical shape. Claim according to 1 to 7 wherein the connector assemblies are inside the winding

9. Claim according to 1 to 7 wherein the connector assemblies are outside the winding

10. Claim according to 8 wherein the connector assemblies are inserted into a housing in the core

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