FR2785138A1 - Electrically heated rug, has one or more very low voltage elements of mechanically robust conductor secured between fabric sheets protected by outer textile layers - Google Patents

Abstract

The alloy conductor comprises e.g. 6 or 7 0.3mm diameter strands, lightly twisted to provide cohesion, with minimum inductance, and insulated. It is laid in a serpentine or looped configuration (3), maintained by suitably interposed lines of sewing or adhesive, between highly flexible support sheets (2) with good insulating properties, and connected to the mains upply through a controller (8). One or more such elements, with supporting sheets, are enclosed between outer protective covers, sewn together round the edges and, opt., at internal points. Identical or different materials may be chosen for upper and lower covers, (5,6) felts or moquettes being suitable, or a fire-resistant fabric. A typical armchair throwover will have separate seat and back elements. In the controller (8) the incoming mains supply is processed to produce a variable output below 12v with double insulation characteristics and protection against overloads, excess temperatures and short-circuits.

Description

 The present invention relates to a new electric heating device comprising a flexible heating sheet and a control device.

 There are already heating blankets or heating mattress covers comprising a long resistant wire shaped in a zigzag, inserted and held by stitching between two flexible textile sheets.

 The fi! resistant is supplied with 220 V and controlled by a single stop-stop unit and double heating position.

 To produce the voltage drop and the necessary Joule effect, the wire is very long and thin (0.05 to 0.2 mm) and wound around a central insulating core, for example made of fiberglass (significantly increasing its mechanical resistance), the whole being embedded in an insulating sheath. The winding of the wire creates a detrimental inductance effect.

 Despite the presence of the central core, the resistant wire remains fragile and the use of this type of heating mat remains limited.

 The applicant has set itself the objective of producing a heating mat which can be used in particular as a heating mat, placed on the same floor and the pressure and shear strength of which is high enough for one to be able to walk there in shoes.

 Since the technology and components of known heating layers are not suitable, the applicant has thus encountered a first technical problem to be solved.

 He encountered another technical problem in terms of electrical safety. A carpet being more exposed than a blanket to the risk of electrocution due for example to the spillage of a liquid, to accidental tearing, etc.

 Another problem still to be solved was the elimination of the winding to reduce the inductance effect.

 The applicant simultaneously resolved all of these problems by using a larger wire which can be supplied with low voltage and no longer needs to be wound around a central core.

 According to the invention, all these problems are solved by a movable electric heating device of the heating sheet type with control device, characterized in that it comprises at least one heating layer formed by at least one heating wire arranged in a zigzag or in loops, inserted between two flexible support plies, and in that the heating wire is a multi-strand wire supplied with very low voltage alternating current by means of a control unit itself connected to the mains voltage.

 In addition, the heating layer (s) are protected by a carpet and an under carpet assembled by a border seam.

 Preferably, the strands constituting the conductive wire are slightly twisted to ensure cohesion without creating an inductance effect.

 Depending on the type of use, several independent heating zones can be provided in the same carpet, for example an armchair carpet will have two of them to heat the seat and the back of the armchair independently or simultaneously.

 The invention also relates to a specific control block that supplies power from the mains and deliver a very low voltage output, comprising galvanic isolation.

The invention will be better understood using the following description made with reference to the appended figures: FIG. 1: exploded overview of a heating mat according to the invention given as
non-limiting exemplary embodiment; -Figure 2: partial and detailed view of the heating part of the figure; -Figure 3: block diagram of an electronic control unit that can be
combined with a heating mat according to the invention, -figure 4: diagram showing a heating mat for an armchair.

 The heating mat shown in Figures 1 and 2, given by way of nonlimiting example of the invention, comprises a heating layer (1) formed of a heating wire (3) arranged in a zigzag or in loops, inserted between two layers support (2) made of electrically insulating and flexible material in three dimensions.

 The support plies (2) are assembled together for example by glue stitches or parallel seams (4) arranged in the axes of the loops so as to keep them separated from each other.

 The heating layer (1) is protected by a mat (5) and an underlay (6) placed on either side of the layer (1) and assembled for example by a seam at the edge and if necessary by junctions or intermediate seams.

 It is possible to provide alternative embodiments with several heating wires and / or with other forms of stitching (for example perpendicular to the axis of the loops).

 For the carpet (5) and the under-carpet (6), one can choose according to the use of identical or different materials from the following examples. a non-woven tablecloth, a cut out of carpet, a textile meeting fire classification standards, etc.

 The heating conductive wire used is a multi-strand alloy wire, for example with 6 or 7 strands with a diameter of about 0.3 mm, slightly twisted to ensure their cohesion without creating an inductance effect, and covered by a flexible insulating sheath.

 The conducting wire (3) is supplied with alternating current by means of an electronic control unit (7), the functional diagram of which is given in FIG. 3, and mounted in a protective box (8).

 The control unit (7) performs several functions.

 It lowers the supply voltage to the very low voltage level (less than 12 volts), provides double insulation, makes it possible to vary the voltage at the request of the user in order to adjust the power corresponding to his need.

 It also provides regulation, protection against overloads, against temperature rises and against short-circuits.

 The functional diagram shows, between the inputs (15) at 220 V, 50 Hz and the outputs (16) protected very low voltage: the stage (9) acting as filter and rectifier,) 'stage (10) of treatment signal, the stage (11) of adjustment, the stage (12) of galvanic isolation, security means (13) and a status viewer (14).

 The block (7) is easily adaptable to a heating sheet according to the invention which would include several heating conductive wires such as (3) distributed in several heating zones in the same layer (1), or in several layers such as (1) inserted between the mat and the underlay.

 The alternating current can be sinusoidal or not.

 A heating sheet according to the invention can be an integral part of a carpet, or be attached under a carpet, a carpet or other covering placed on the floor, or include a removable cover or not.

 It allows, from a simple outlet to create a mobile mini heating panel, usable by adults, elderly, children, animals, plants, objects fearful of cold or humidity.

 A heating sheet according to the invention can comprise, as indicated above, several heating layers such as (1).

 One can, for example, provide in a heating mat for an armchair (see Figure 4) two separate heating zones, the flexibility of which allows them to match the shapes of the backrest and seat.

Claims (8)

 CLAIMS 1. Movable electric heating device of the heating sheet type with control device, characterized in that it comprises at least one heating layer (1) formed of at least one heating wire (3) arranged in a zigzag or in loops, inserted between two flexible support plies (2), and in that the heating wire is a multi-strand wire supplied with very low voltage alternating current by means of a control unit (7) luimme connected to the mains voltage. 2. Heating device according to claim 1, characterized in that the support plies (2) are assembled by stitching. 3. Heating device according to claim 1, characterized in that the support plies (2) are assembled by gluing. 4. Heating device according to one of claims 1 to 3, characterized in that the heating layer or layers are protected by a carpet (5) and an under carpet (6) assembled at least by a border seam. 5. Heating device according to one of claims 1 to 4, characterized in that the strands constituting the conductive wire are slightly twisted to ensure cohesion without creating an inductance effect. 6. Heating device according to one of claims 1 to 5, characterized in that it comprises two heating layers such as (1) inserted between the same carpet and the same under carpet. 7. Electronic control unit, characterized in that it is specifically designed for controlling at least one heating device according to one of claims 1 to 6 and in that it is supplied from the mains and delivers very low voltage output, and in that it includes galvanic isolation (12). 8. Control unit according to claim 7, characterized in that it further comprises a stage (11) for tension adjustment.