Assembling module of induction coils of a induction heating cooking area and cooking area including the said modules

p0001The invention relates to an induction heating cooking zone comprising joining modules of the induction coils.

p0002More specifically the invention relates to a cooking zone for inductively heating at least a cooking vessel placed on a non-magnetic support plate constituting the above the baking zone, said baking zone comprising at least two coils induction under the support plate and connected to independent generators.

p0003The French patent published under number 2758934 describes a cooking zone consisting of at least two standard induction coils, each powered by a standard generator so that a container can be placed on the cooking zone by covering at least partially the induction coils. A cooking zone as described in this patent is complex to manufacture, especially when it comes to placing a large number of induction coils to cover the cooking zone. Indeed, each induction coil is positioned independently which complicates the assembly and can result in poor distribution of the magnetic field on the cooking zone.

p0004The <patcit id="pcit0001" dnum="US4665893A"><text>patent US4665893</text></patcit> discloses a cooking zone made from rectangular modules supporting two induction coils, the electronics for supplying the coils and ventilation. Each module thus functions independently. However, the assembly of these modules is binding to the extent that it does not allow to build cooking zones of varying shape, and wherein the distribution of the resulting magnetic field is not regular.

p0005The present invention aims to offer a cooking area that improves the known devices by providing a connecting means of the induction coils in the non-magnetic support plate constituting a modular structure for building shapes and sizes zone cooking, while facilitating the assembly of the table and ensure a regular distribution of magnetic field, all compatible with mass production.

p0006To this end, the present invention provides, in a first aspect, a cooking zone for inductively heating at least a cooking vessel placed on a plate magnetic support, for example glass-ceramic constituting the above the cooking zone, said cooking zone comprising at least two inductors connected to generators, said induction coils being grouped into at least two induction coils modules, and fixed on the same support. Each bracket is dimensioned so that the gap between two adjacent induction coils and embodied by different carriers, the same as between two adjacent induction coils and carried by the same support.

p0007A cooking zone comprising these modules can thus be easily manufactured and can have very varied forms.

p0008The cooking area is <b>characterized in that</b> each support comprises a median concave area whose maximum radius of curvature is equal to the external radius of the end of the module.

p0009Thus, the interlocking of the modules is possible and paving of the cooking zone using these modules is smooth. The generated magnetic field then has a regular geometry and homogeneous over the entire cooking surface.

p0010According to a preferred characteristic of the invention of magnetic conductive elements, preferably ferrite, are placed below each induction coil and are carried by the same support as said induction coil.

p0011Thereby, the magnetic conductive elements that channel the magnetic field lines are simply placed below each induction coil and the latter can be pre-assembled completely prior to final assembly of the cooking zone.

p0012In a preferred embodiment, the cooking zone is <b>characterized in that</b> each module includes means for measuring the temperature of the container at least partially covering the module.

p0013In a preferred embodiment, the cooking zone is <b>characterized in that</b> the temperature measuring means comprises a temperature sensor delivering a measurement of the temperature and a heat conductor placed in thermal contact with the temperature sensor and which extends above each induction coil.

p0014In a preferred embodiment, the cooking zone is characterized in that each induction coil has an outer diameter between 60 mm and 100 mm. In a preferred embodiment, the cooking zone is characterized in that the center of each induction coil is spaced from the center of each adjacent induction coil by a distance of 65 mm and 105 mm. In a preferred embodiment, the cooking zone is characterized in that the distance between each adjacent induction coil is constant over the entire cooking area. In a preferred embodiment, the cooking zone is characterized in that it comprises at least an assembly plate on which is fixed at least one module, so that the equidistance between each adjacent induction coil is guaranteed . In a preferred embodiment, the cooking zone is characterized in that each connecting plate is provided with positioning holes in which are placed the corresponding pads on the module carriers. In a preferred embodiment, the cooking zone is characterized in that each connecting plate is bonded to at least one neighboring plate by a connecting means guaranteeing equidistance between each adjacent induction coil. In a preferred embodiment, the cooking zone is characterized in that the modules are made up of three induction coils disposed in an equilateral triangle. Preferably, the module temperature sensor is placed in the center of the equilateral triangle formed by the centers of the induction coils. In a preferred embodiment, the cooking zone is characterized in that said cooking area comprises only modules of three induction coils.

p0015Other features and advantages of the invention emerge from the description which follows, given by way of nonlimiting example, with reference to the accompanying drawings in which: <ul><li>The <figref idrefs="f0001">figure 1</figref> is a simplified perspective view of a module consisting of two induction coils and a carrier;</li><li>The <figref idrefs="f0001">2</figref> is a simplified perspective view of the assembly of two modules of two induction coils;</li><li>The <figref idrefs="f0001">3</figref> is an assembly plan view of two modules;</li><li>The <figref idrefs="f0002">4</figref> is a perspective view of a module of two induction coils associated with the temperature measuring device;</li><li>The <figref idrefs="f0002">5</figref> is a perspective view of a module consisting of three induction coils and a carrier;</li><li>The <figref idrefs="f0002">6</figref> is a perspective view of a module of three induction coils with their temperature measuring device;</li><li>The <figref idrefs="f0003">7</figref> is a perspective view of the upper face of the support of a three induction coils module;</li><li>The <figref idrefs="f0003">8</figref> is a perspective view of the underside of the carrier of a three induction coils module;</li><li>The <figref idrefs="f0004">9</figref> is a perspective view of one of three coils of an alternative form of induction module;</li><li>The <figref idrefs="f0004">Figure 10</figref> is a perspective view of a module of four induction coils;</li><li>The <figref idrefs="f0005">11</figref> is a plan view of a support assembly on which are placed two module carriers;</li><li>The <figref idrefs="f0006">Figure 12</figref> is a sectional view of the assembly of two modules;</li><li>The <figref idrefs="f0006">13</figref> is a sectional view of the assembly of two connection plates; and</li><li>The <figref idrefs="f0007">14 to 16</figref> are examples of modules available to them to achieve the cooking area.</li></ul>

p0016The <figref idrefs="f0001">figure 1</figref> is a schematic of a module 1 perspective view comprising two induction coils 2 conventionally realized by a spiral coil of copper son and a module carrier 3. The induction coil 2 is fixed on the support 3 preferentially with a bonding process. To always fix the induction coil 2 to a definite place, a recessed slot 9 is provided for each induction coil 2 in the holder 3. Thus the mounting of induction coils 2 on support 3 is facilitated and the distance between each induction coil 2 of the same module 1 are constants. The perimeter "8" obtained contains a concave middle portion 4 allowing the positioning of another module 1 near the first while maintaining a constant distance between the centers of the induction coils 2.

p0017The <figref idrefs="f0001">2</figref> shows the arrangement of two modules 1 of two induction coils 2 so that the convex portion of one of the two modules 1 corresponds to the concave portion of the other. In this configuration the two modules 1 can be placed close to each other which ensures a constant distance d between each induction coil 2: it is possible to place the centers of the induction coils 2 at the vertices of a rhombus whose sides have a length equal to the distance between the centers of two induction coils 2 on the same support 3.

p0018The <figref idrefs="f0001">3</figref> shows the geometry of the middle part 4 so that this positioning is possible. Let A and B centers of two adjacent induction coils 2 arranged on a first support 3. Let C be the center of an induction coil 2 adjacent, following a second support 3. If the segments are considered right [CA] and [CB], it is possible to define their mediating M1 and M2 which pass through the points T1 and T2 [CA] environments respectively and [CB]. Note that T1 is the midpoint of [CA] and T2 the midpoint of [BC] and AC distance being equal to the distance BC, the four dist ance CT1, AT1, CT2 and BT2 are equal and greater than or equal to the value R of the radius of curvature of the outer part of a module carrier 3 1. the concave region of the central part 4 of a first support 3 is defined between the two points T1 and T2. The material forming the first support 3 can fill an area not exceeding an arc having: to end the points T1 and T2, to the center point C and the distance radius R. In order to facilitate assembly and consider games assembly of the various components, a minimum gap is defined between the two modules 1 in the concave area between the two points T1 and T2. Preferably, this space is 1mm.

p0019Voluntarily, the shape of the support 3 beyond the outline of the induction coils 2 while following a constant distance e the edge of the induction coils 2 on the extremities of the support 3. Thus the radius R which is defined above is greater than the radius r of an induction coil. Thus the maintenance, and mechanical protection of the induction coils are provided while allowing great freedom of positioning the modules 1. The support 3 is preferably of a composite material resistant to heat, for example a polyester loaded fiberglass resin, and the thickness e and between 0.5 and 2 mm, and preferably equal to 1 mm.

p0020The <figref idrefs="f0002">4</figref> 1 shows a module with a temperature measuring device 5. In fact, it is typically useful to measure the temperature above the induction coils 2 to prevent overheating of containers. Usually each induction coil 2 has a temperature measuring device 5, but in the case of the invention, the same sensor 7, namely an NTC, is used to measure the vessel bottom temperature heated by one or both of the induction coils through a heat conductor 6 which extends above the two induction coils 2. preferably, this heat conductor 6 is a flat aluminum plate with ramifications extend above the induction coils 2 in a direction substantially perpendicular to the turns of the induction coil. 5 the temperature measuring device is in thermal contact with the plate 20 of magnetic material supporting the containers and thermally insulated from the inductor 2 so that it is not influenced by the temperature of the induction coil 2.

p0021In a preferred embodiment of the invention illustrated in <figref idrefs="f0002">5</figref> Module 1 used is a module 1 comprising three induction coils 2 and a support 3 in the shape of clover. The centers of the induction coils 2 are disposed at the vertices of an equilateral triangle with side length d. As with the module 1 two induction coils 2, each induction coil 2 has its location 9 in hollow on the support 3 and is adhered thereto. Similarly, the outer shape of the support 3 exceeds induction coils 2 of a thickness e of the end portions of the support 3 and the middle portions 4 between each induction coil have a concavity whose arc , defined as for the module 1 to the two induction coils 2, constitutes the limit of the presence of the material. Of course, all forms of middle part 4 of support 3 does not exceed this arc are compatible with the invention.

p0022The <figref idrefs="f0002">6</figref> shows a module 1 in three induction coils 2 fitted with its temperature measurement device 5 comprising a for example an NTC 7 and the center of a heat conductor 6 reported above whose branches extend au over induction coils 2. A central hole 8 is provided in the support 3 to place the NTC 7 and login son. Alternatively, the NTC 7 can be placed in the center of one of the induction coils 2 of module 1, the heat conductor 6 having a shape which allows it to extend above each induction coil 2 (not represent).

p0023An accurate view of the module of the embodiment 1-3 inductors 2 is given to <figref idrefs="f0003">Figures 7 and 8</figref>.

p0024To the <figref idrefs="f0003">7</figref>Is given a view of the upper face of a support 3 of the modules 1. Three slots 9 are formed in the support 3. These have a depth of about 2 mm and a diameter of substantially 85 mm. The induction coils 2 which will be placed in these locations 9 have a diameter of 84 mm. The central connection wire from the inductor 2 passes through the hole 10 to be connected to the generator located below, while the outdoor connecting wire passes through a hole 11 formed on the edge of the support to be also connected to the generator . To keep a constant distance d substantially equal to 89 mm, the thickness of material between two induction coils 2 of a same support 3 is substantially 3 mm.

p0025The <figref idrefs="f0003">8</figref> gives a view of the underside of a support 3 integrated in the modules 1 according to the invention. At least one stud 14 is placed on this surface for positioning of the module 1 on a support plate 12 as shown in<figref idrefs="f0005">11</figref>. In fact, each post 14 is located in a corresponding hole of the support plate 12 thus ensuring the placement module 1 of the cooking zone. Preferably the studs 14 are two in number in each support 3 of module 1 and to facilitate the manufacture of the support 3, one of these two studs 14 is preferably located in the module center 1 in correspondence with the hole 8 passage of the NTC connection son 7. the second bushing 14 is located anywhere on the lower surface of the support 3, but for ease of manufacture of said medium 3 of molded plastic material will be preferably placed at a middle portion of the support. Having two pads 14 of positioning allows to place and easily orient the modules 1 of the cooking zone. Alternative locations 13 may be provided on the underside of the carrier 3 to move the magnetic conducting elements (not shown) to the right of the induction coils 2. These magnetic conductive elements are conventionally used to channel the field lines emitted by the induction coils 2 in the bottom of the module 1. in the same manner as for known induction coils, magnetic conductive members are adhered to the underside of the carrier 3 in the locations reserved for this purpose.

p0026The <figref idrefs="f0004">Figures 9 and 10</figref> show alternative forms of the modules 1. In fact, it is possible to make a module 1 of three induction coils 2 forming an angle of 120 ° as shown in <figref idrefs="f0004">9</figref>. The centers of the induction coils 2 are then at the vertices of an isosceles triangle with two sides of equal length to length and enclose an angle of 120 °. It is still possible to make a module of four induction coils 2 arranged in diamond as shown in<figref idrefs="f0004">Figure 10</figref>.

p0027The <figref idrefs="f0005">11</figref> shows a preferred assembly device. In this case, the one used modules are modules 1 of three induction coils 2. The two modules 1 are placed head to tail so that the distance between each center of adjacent induction coils 2 are substantially equal to d. The modules 1 are placed on the support plates 12 having holes in which the studs 14 of the supports 3 are placed as shown in<figref idrefs="f0006">Figure 12</figref>. Of course, these holes are disposed previously to correspond to the arrangement of modules searched. Preferably a support plate 12 comprises three modules 1 of three induction coils 2 cloverleaf.

p0028Thus the cooking zone can it be formed of the assembly of several support plates 12. The <figref idrefs="f0006">13</figref> illustrates this assembly is achieved through a 16 piece U-shaped sized to ensure a distance between the centers of two neighboring induction coils 2. The support plates 12 as that shown in <figref idrefs="f0006">13</figref>, Are provided with additional holes to allow the passage of the connecting son of the induction coils 2 as well as of temperature sensors 7 so that they can be connected to all generators cards (not shown) conventionally associated with each induction coil 2 and which feed current to the induction coils 2.

p0029Such an assembly method also allows to create very different cooking zones. The<figref idrefs="f0007">14 to 16</figref> furnish non-limiting examples of feasible cooking zone shapes.

p0030The <figref idrefs="f0007">Figure 14</figref> shows the preferred embodiment of the invention. In this case, modules 1 used are that modules 1 of three induction coils 2 arranged in a triangle 17. The proposed arrangement of the twelve modules 1 to create a cooking zone where the power distribution will be any regular leaving a central place for the positioning of the keypad 18 of the cooking zone.

p0031The <figref idrefs="f0007">Figure 15</figref> provides an alternative arrangement of the same twelve modules 1 leaving room for the control keypad in a corner of the table.

p0032The <figref idrefs="f0007">Figure 16</figref> shows another alternative arrangement of modules 1, but in this case one of the modules of three induction coils 2 represented by triangles 17 and modules 1 of two induction coils 2 represented by rectangles 19. This example shows the great adaptability of the assembly method according to the invention.

p0033The present invention allows to create induction heating cooking zones including many induction coils 2 arranged regularly to provide consistent magnetic fields over the entire cooking surface while being simple to assemble industrially.