INERTIAL COOKTOP AND MANUFACTURING METHOD

Abstract

A food cooking appliance includes a panel having a thermal inertia, and a heater to heat the panel from the bottom face thereof. The panel has at least two plates that lie on top of each other. Plates are made of different materials and are in close contact with one another across part of the facing surfaces thereof. The upper plate being suitable to receive the food to be cooked, and is made of stainless steel or titanium. The lower plate is made of cast iron. A method for manufacturing a panel consisting of two metal plates that are made of different materials and are bonded together in a metal casting process.

Claims

1. A food cooking device, comprising a thermal inertia griddle comprising a bottom surface thereof and a single heater, in contact with the bottom surface, to heat the griddle by the bottom surface thereof, the griddle consisting of: a top stacked plate providing a surface resistance and the top stacked plate defining a cooking surface suitable to receive a food to be cooked; a bottom stacked plate providing a thermal inertia and a thermal conduction, the bottom stacked plate defining the bottom surface, the bottom stacked plate comprising a plurality of elements arranged side by side to prevent a differential expansion between the top stacked plate and the bottom stacked plate, each of the plurality of elements configured as a group of lozenges; wherein the top and bottom stacked plates are made of different materials, the top and bottom stacked plates are kept in contact on a part of respective surfaces thereof which are placed opposite one another; wherein the top stacked plate is made of stainless steel or titanium, and the bottom stacked plate is made of cast iron.

2. The food cooking device of claim 1, wherein a thickness of the top stacked plate is less than a thickness of the bottom stacked plate.

3. The food cooking device of claim 2, wherein the thickness of the top stacked plate is less than two to ten times less than the thickness of the bottom stacked plate.

4. The food cooking device of claim 1, wherein a thickness of the top stacked plate is from one to five millimeters, and wherein a thickness of the bottom plate is from 0.5 to two centimeters.

5. The food cooking device of claim 1, wherein the bottom stacked plate is composed of a plurality of elements arranged side by side.

6. The food cooking device of claim 5, wherein faces of the lozenges are not parallel to outer edges of the top stacked plate.

7. The food cooking device of claim 1, wherein the top and bottom stacked plates are kept in contact with each other by a hot-bonding, without using external material.

8. The food cooking device of claim 1, wherein faces of each lozenge are not parallel to outer edges of the top stacked plate.

9. A method for hot-bonding a cast iron plate and a stainless steel or titanium plate to manufacture the food cooking device of claim 1, comprising steps of: producing the stainless steel or titanium plate to predetermined dimensions; inserting the stainless steel or titanium plate in a cold state into a foundry mold; and adding molten cast iron into the foundry mold to make the cast iron plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The features and advantages of the invention will be better understood thanks to the following description which discloses the features of the invention by way of a non-limiting example of use.

[0031] The description is based on the appended figures in which:

[0032] FIG. 1 is a side view of a griddle in an embodiment of the invention,

[0033] FIG. 2 is a bottom view of such a griddle, in a particular embodiment, and

[0034] FIG. 3 is a block diagram of the steps of a method of manufacturing a griddle formed from two materials bonded along the opposing surface thereof.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0035] The invention falls within the scope of a cooking device using a cooktop with thermal inertia. The description relates only to the cooktop itself. The burners and other elements of the heating device are assumed to be known per se. As such, they depart from the scope of the present invention, and therefore are not detailed further here.

[0036] As is seen in FIG. 1, which illustrates a side view of such a cooking device comprising the cooktop 10 comprising two stacked plates 11, 12, and a single heater 14.

[0037] The top plate 11 is the actual cooking surface. It is intended to receive the food to be cooked, with which it therefore comes into contact. The top plate in this case is rectangular, but any other shape related to the conditions of use may be feasible. It is, in this case, made of food-grade stainless steel of a type known per se. Food-grade stainless steel is a stainless steel-type alloy, for example iron+chrome (at least 13%)+nickel+carbon, with proportions of these materials suitable for preventing any rusting phenomenon over time. The type of food-grade stainless steel envisaged in this case is that designated by the American reference 304L. Other alloys with equivalent characteristics (particularly resistance to temperature variations) are, however, possible. The top plate 11 can also be made of titanium. Titanium advantageously makes the top plate 11 resistant to corrosion, wear, fire, and particularly to temperature variations.

[0038] In the present exemplary embodiment which is in no way limiting, the thickness thereof is one millimeter.

[0039] The bottom plate 12 forms the heating body. In this case, it is made of cast iron. Alternatively, it may be made of steel, for example open-hearth steel, or any other material having good thermal conduction qualities.

[0040] In the present exemplary embodiment which is in no way limiting, the thickness thereof is five millimeters. This thickness is determined by the thermal inertia qualities desired for the cooktop.

[0041] FIG. 2 shows a bottom view of the griddle. As seen in this figure, the bottom plate 12, made of cast iron, is in fact composed of several elements 13 arranged side by side, so as to prevent the differential expansion problem that may lead to a rupture of the cast iron plate. These elements are, in this case, configured as groups of lozenges, the faces of which are not parallel to the outer edges of the top plate 11. A space of one to a few millimeters is provided between the elements 13.

[0042] In the embodiment given in this case without limitation, the two plates 11, 12 are held in close contact against each other by hot-bonding, without using external material.

[0043] The hot-bonding method comprises a series of steps detailed in FIG. 3.

[0044] In a first step, the stainless steel or titanium plate is made in a conventional manner. Then, this plate is subjected to abrasive scouring of the surface to be bonded.

[0045] Degreasing of the surface to be bonded is then carried out with a solvent, for example of methyl ethyl ketone type.

[0046] The stainless steel or titanium plate is then put into a mold.

[0047] Cast iron is then cast on this plate, followed by slow cooling without thermal shock.

[0048] In an alternative production method, the heating body, i.e., the cast iron bottom plate 12, is made to size by a traditional method.

[0049] Then, in a second step, the bottom plate 12 is inserted in a cold state into a foundry mold.

[0050] In a third step, molten stainless steel or molten titanium is added into this mold.

[0051] In an alternative embodiment, the plates, top 11 and bottom 12, are held in close contact by bolting, screwing or riveting the bottom plate 12 under the top plate 11. In this case, the density of the bolts, screws or rivets is sufficient to maintain a sufficient pressure between the two plates. Typically, these pressing points are spaced a maximum of ten centimeters from each other.

[0052] In another alternative embodiment, the plates, bottom 12 and top 11, are assembled by welding, whether by TIG, spot, continuous roller, etc., method.

ADVANTAGES

[0053] To have all the qualities of plancha cooking (homogeneous cooking surface at more than 300° C.), the main problem is that of the increase in temperature and of maintaining this temperature when cold food is placed on the griddle. The device as described above addresses these problems.

[0054] It combines, firstly, the resistance and the ease of maintaining stainless steel or titanium and, secondly, the conduction and the thermal inertia of cast iron while avoiding the deformation issues specific to cast iron alone. It does not pose a risk to health.