GLASS CERAMIC WORKTOP

Abstract

A method for the manufacture of a worktop formed of at least one glass-ceramic substrate with a surface area of greater than 0.7 m.sup.2 in which at least one cycle of ceramization of a glass plate with a surface area of greater than 0.7 m.sup.2 is carried out in a manner where the rate of passage is reduced or the length of the ceramization furnace or the residence time in said furnace is increased.

Claims

1-15. (canceled)

16. A method for the manufacture of a worktop formed of at least one glass-ceramic substrate with a surface area of greater than 0.7 m.sup.2, wherein at least one cycle of ceramization of a glass plate with a surface area of greater than 0.7 m.sup.2 is carried out in a manner where the rate of passage is reduced by at least 25%, or the length of the ceramization furnace or the residence time in said furnace is increased by at least 25% with respect to the optimal or normal rate, length or residence time respectively, in order to obtain a glass-ceramic substrate with a surface area of less than 0.4 m.sup.2.

17. The method according to claim 16, wherein at least one cycle of ceramization of a glass plate with a surface area of greater than 0.7 m.sup.2 is carried out in a manner where the rate of passage is reduced by at least 50%, or the length of the ceramization furnace or the residence time in said furnace is increased by at least 50% with respect to the optimal or normal rate, length or residence time respectively, in order to obtain a glass-ceramic substrate with a surface area of less than 0.4 m.sup.2.

18. The method according to claim 16, wherein the worktop produced by said method is a worktop formed of a substrate made of glass-ceramic material with a surface area of greater than 0.7 m.sup.2, said substrate exhibiting a luminosity L* of greater than 10, a light transmission T.sub.L of less than 50%, a haze of greater than 15%, and an opacity indicator of greater than 90 and of less than or equal to 100.

19. The method according to claim 18, wherein the substrate exhibits a flatness of less than 0.1% of the diagonal of the substrate.

20. The method according to claim 18, wherein the surface area of the substrate is greater than 0.9 m.sup.2, the thickness of said substrate is at least 2 mm, and the thickness of the substrate is less than 15 mm.

21. The method according to claim 18, wherein the glass-ceramic material comprises the following constituents expressed as percentages by weight: SiO.sub.2: 52-75%; Al.sub.2O.sub.3: 18-27%; Li.sub.2O: 2.5-5.5%; K.sub.2O: 0-3%; Na.sub.2O: 0-3%; ZnO: 0-4%; MgO: 0-5%; CaO: 0-2.5%; BaO: 0-3.5%; SrO: 0-2%; TiO.sub.2: 0-5.5%; ZrO.sub.2: 0-3%; P.sub.2O.sub.5: 0-8%; B.sub.2O.sub.3: 0-5%.

22. The method according to claim 18, wherein the substrate exhibits a luminosity L* of greater than 15, a haze of greater than 20%, a light transmission T.sub.L of less than 32%, and an opacity indicator of greater than 95 and of less than or equal to 100.

23. The method according to claim 16, further comprising assembling the worktop with: at least one heating element, and at least one interface for communication with at least one element of the worktop, and/or with at least one external element for wireless communication, so as to form an item of equipment.

24. The method according to claim 23, wherein said item of equipment is devoid of light source(s).

25. The method according to claim 18, further comprising assembling the worktop with: at least one heating element, and at least one interface for communication with at least one element of the worktop, and/or with at least one external element for wireless communication, so as to form an item of equipment.

26. The method according to claim 25, wherein said item of equipment is devoid of light source(s).

Description

[0049] Other advantageous characteristics and details will emerge below from the description of a nonlimiting embodiment of the invention, with reference to the appended drawings, in which:

[0050] FIG. 1 represents a diagrammatic perspective view of an item of equipment according to the invention;

[0051] FIG. 2 represents a diagrammatic top view of a similar item of equipment (the utensils at the surface or the underlying elements of the piece of furniture not being represented);

[0052] FIG. 3 represents a diagrammatic side view in which a section of the piece of furniture (23) has been removed in order to reveal certain components of the item of equipment.

[0053] In this example, the item of equipment (1) according to the invention comprises a piece of furniture (2) formed of a casing (4) surmounted by a worktop (5) formed of at least one monolithic substrate (6) made of glass-ceramic, this substrate occupying the majority (in this instance all) of the surface (measured on the upper face) of the worktop. This substrate is, for example, a plate of translucent white color of the type of that sold under the KeraWhite reference by Eurokera, this plate exhibiting a surface area of 4.3 m.sup.2, a smooth upper face and a smooth lower face (it also being possible for this face to be provided with tear drops) and a thickness of 12 mm, and exhibiting a luminosity L* of 88.47, a haze of 97.3%, a light transmission T.sub.L of 19.0% and an opacity indicator of 97.0. This substrate is, for example, obtained by proceeding as in the patent application WO9906334 but by reducing the rate of passage in the ceramization furnace by 50%.

[0054] This substrate can also, if appropriate, be colored or provided with a resin layer on its lower face, in order to give a coloring to the substrate, for example be provided with a coat of paint based on silicone resin giving a gray coloring, the worktop (coated substrate) thus exhibiting a luminosity L* of 79.45, a haze of 100%, a light transmission T.sub.L of 1.53% and an opacity indicator of 99.94, this layer having being applied to the glass-ceramic substrate after it has been prepared.

[0055] Alternatively, this substrate can, for example, also be a plate of translucent white color of the type of that sold under the KeraWhite TC reference by Eurokera, this plate exhibiting a surface area of 2.7 m.sup.2, a smooth upper face and a smooth lower face (it being possible for this face also to be provided with teardrops) and a thickness of 7 mm, exhibiting a luminosity L* of 80.34, a haze of 98.2%, a light transmission T.sub.L of 27.2% and an opacity indicator of 94.5.

[0056] In both cases, the substrate made of glass-ceramic obtained exhibits a flatness of less than 2 mm (the flatness obtained being between 2 and 3 mm for a rate reduced by only 25% and being more than 15 mm for a rate unchanged with respect to that used in the abovementioned patent application to order to obtain a plate with standard dimensions of less than 0.4 m.sup.2), the flatness desired for good optical properties and good coupling and thermal efficiency properties in particular being less than 3 mm and preferably less than 2 mm.

[0057] The item of equipment additionally comprises, in the present example, three heating elements (7), for example inductors, positioned under the plate (6) and fastened to a support (10). These inductors are, in the present case, distributed in the middle of the work surface but might just as easily be located at one end of the top.

[0058] The item of equipment also comprises decorations (9, 11), for example made of enamel, for example placed on the upper or lower face of the substrate. These decorations, for example in the form of circles of color (9) delimiting each location (it being possible for the colors, if appropriate, to be identical or different according to the locations) and encircling the inductors, make it possible, for example, to signal the cooking locations in order to prevent contact with them when the heating elements are activated. They can also consist of information, logos, images (11), and the like.

[0059] The item of equipment additionally comprises at least one interface (12) (hidden by the substrate) for communication with the heating elements, this interface also communicating wirelessly with an external unit in the form, for example, of a touch tablet (13) for the activation of different zones and functions of the plate or of the item of equipment. The external unit can be advantageously movable and lie on the worktop (FIG. 1) or be used for the remote activation (FIG. 3) of different zones or functions. Alternatively or cumulatively, the interface might also comprise or be connected to a permanent control panel located on the surface of the substrate (2) for the activation of different zones and functions, in particular of the substrate.

[0060] If appropriate, the item of equipment can also be combined with or comprise a suction hood (14) overhanging the worktop.

[0061] The item of equipment also comprises other elements, in particular electrical cables (15) for the activation of the heating elements, and comprises drawers (16) or cupboards (17) inserted into the casing supporting the worktop, for storing various articles, and the like. The item of equipment can also comprise other elements; for example, the worktop can comprise a trim, the substrate can be coated with a localized or nonlocalized fixed decoration, for example made of enamel, the casing can be uninterrupted or comprise different recesses (such as the recess (18)) or integrate other elements (for example a built-in oven, and the like). The worktop (5) can be used for different purposes, such as writing (as symbolized by the paper and the pen (19)), the support for objects (as symbolized by the tableware (20)), while making possible the cooking of food (as symbolized by the cooking receptacles (21)), and the like. If appropriate, the casing can also be replaced by supporting legs (for example only the walls 22 and 23, or four legs at the four corners, the item of equipment under the worktop in this case preferably being hidden by a localized enclosure with a thickness of a few centimeters under the substrate), such as a table.

[0062] The item of equipment according to the invention can in particular be advantageously used to produce a new range of interactive and multiuse pieces of furniture in particular integrating cooking zones or a cooking function.