EP0930468B1 - Cooking apparatus - Google Patents

Abstract

The cooking appliance has at least one upper essentially plane plate and at least one heating element. The plate has a concave shape (9) under which the heating element is placed. This is calibrated to a maximum temperature of the order of 450 degrees C. The heater has two temperature limiters which are triggered at maximum temperatures of 400 to 580 degrees C. The heating element, is regulated by a thermostat, and is of an annular shape placed peripherally under the concavity.

Description

The present invention relates to a cooking appliance comprising an essentially flat upper plate and at least one cooking zone.

In the field of equipment intended for domestic use, changes in appliances used in the kitchen, imposed by aesthetic and / or technical constraints, have been constant and significant in recent years.

In particular, the design of the cooking appliances has undergone many modifications.

Thus, it is known for a long time cookers enamelled sheet using as firing burners natural gas or LPG. The advantages provided by such stoves, directly related to the nature of the aforementioned cooking stoves, are well understood: flexibility of use, low thermal inertia, immediate visibility of the settings of the heating power. The disadvantages of these stoves are also disadvantages such as, for example, the presence of a metal frame-shaped grille which frequent cleaning is necessary.

Moreover, the aesthetics of these stoves seem more and more outmoded, even with the recent use of a molded glass plate on which are placed the gas burners.

It is also known for a long time cooktops commonly called "electric plates" (as for example described in the document DE-A-1765832 ) using as electric heaters electric resistors arranged under circular metal plates. These hobs have the essential advantage of no longer having metal grids since the cooking utensils are placed directly on the aforementioned hotplates.

Concomitant with the appearance of the concept of integrated kitchen, a significant change has been made in the hobs. This change consisted in using as plates vitroceramic plates (as for example described in the document FR-A-2130180 ). This document discloses a cooking appliance comprising at least one essentially flat top plate made of glass-ceramic material having at least one concavity formed in this plate and in the same material with at least one heating element.

These plates, now widely available, have, among other things, two notable advantages, namely the ease of cleaning (because the surface of a ceramic hob is essentially flat) and a resolutely new exterior appearance conferring a more modern look.

In addition, these vitroceramic hobs have been associated with new hobs such as halogen lamps and induction heaters.

In addition to the aforementioned modifications made to the cooking appliances, the design of the cooking utensils has also undergone numerous modifications.

In particular, the cooking pots of the stove or pan type, although having retained their original function, namely to heat and / or cook the food they contain, have seen their appearance and their structure evolve considerably.

Some of these modifications were imposed only by aesthetic constraints (color, decorative pattern).

Another part of these modifications is related to the fact that the cooking hobs have also evolved both in their dimensions (dimensions defining the active part of heating) and by their nature (halogen lamp hearths, induction heaters).

For example, pots or pans made of ferromagnetic material have been developed so that they can be adapted to induction fireplaces.

However, there is to date a need to improve the adequacy between the parts of the cooking appliances other than the hobs themselves (radiant or halogen heating element, gas burner, inductor) and, d on the other hand, the cooking vessels.

Indeed, in use, an imperfect adequacy can bring various disadvantages.

In the particular case of hobs, the use of specific containers, for example of large dimensions and / or having a particular surface condition, may be difficult on glass ceramic hobs.

Thus, it may be difficult to accurately center the containers, particularly large, to the right of cooking stoves underlying the plate so that their bottom is not necessarily heated homogeneously over their entire area.

Likewise, because the containers are not necessarily limited in their relative displacement with respect to the plate, that is to say that they are not confined to a specific area thereof, they can create superficial scratches, if any, detrimental to the mechanical strength of the plate. From a safety point of view, this can sometimes be dangerous insofar as uninformed people, for example children, handling these same hot containers can, without undue effort, slide them on the plate and in the end, drop them from the hob.

The object of the invention is then to overcome the aforementioned drawbacks and in particular to provide a cooking appliance for domestic use that allows to position with sufficient precision all existing cooking containers while limiting their movement by an uninformed person.

Another object of the invention is to provide a cooking appliance for domestic use that eliminates the use of a cooking vessel.

These objects are achieved according to the invention by a cooking apparatus comprising at least one substantially flat upper plate and at least one cooking zone, this apparatus being as defined in claim 1.

It should be understood that, within the context of the invention, the term "cooking hearth" must be understood to mean any heating means such as a radiant element or a gas burner and / or any means that contribute to heating, such as an inductor contributing to induction heating.

According to an advantageous characteristic of the invention, the cooking chamber is a heating element. This heating element can be radiant or halogen.

The term "radiant" is to be understood as consisting of an electrical resistance.

This may be in the form of a conductive wire. It can also be in the form of a conductive layer of adequate resistivity such as that described in the Certificate of Utility FR / U 2 744 116 . The choice of such a shape may be advantageous when it is preferable that the cooking appliance according to the invention retains a space comparable to that of a cooking appliance of the same type according to the state of the art. that is to say a cooking apparatus not comprising a concavity according to the invention.

This can be particularly the case in configurations where the concavity has a significant depth.

Preferably, the heating element according to the invention is calibrated at a maximum temperature of the order of 450 ° C. This allows direct cooking of all types of food in the concavity according to the invention without risk of excessive overheating.

It is also possible to couple the heating element to two temperature limiters triggered at a maximum temperature of 400 ° C and 580 ° C, these temperatures being understood as those established at the concavity surface.

The user can, in this configuration, either to direct cooking food or to achieve it through conventional cooking utensils.

To regulate the heating power of the heating element, it is preferable to do this by a thermostat operating from the measurement of the temperature between the plate and the cooking stove considered. This avoids the use of an energy meter that imposes a percentage of time between the operating state and the stop.

As a preferred arrangement, the heating element advantageously has an annular shape and is placed in peripheral part under the concavity.

According to an advantageous characteristic of the invention, the plate may be made of glass-ceramic material.

According to another advantageous characteristic of the invention, the concavity itself is made of glass-ceramic material.

It can then be a ceramic hob whose appearance is in harmony with the kitchen furniture as described in the international patent application WO 98/01676 .

Advantageously, the plate according to the invention may further comprise at least one opening in which is inserted an atmospheric type gas burner and / or at least one flat heating zone under which is placed another cooking stove, such as a heating element or an induction heater.

According to this configuration, the cooking appliance according to the invention is mixed because it comprises at least two different heat sources by direct and indirect transfer thereof.

Such a configuration allows the user to cook and / or reheat food as desired, including taking into account certain criteria, such as the nature of food, possibly the type of container (s) made available.

According to this same configuration, the plate consists of at least two juxtaposed modules, one of the two modules comprising at least one concavity, the other comprising at least one opening and / or at least one planar heating zone. This modular configuration of the plate is very advantageous, especially in the case where the cooking appliance constitutes a hob integrated in the kitchen furniture.

Indeed, from the design of the so-called "integrated" kitchen, the end user can make choices on several levels.

In addition to the choice of the desired furniture and its arrangement, it can now choose the nature of the hobs that make up the hob and the way they are arranged in the latter.

Preferably, the aforementioned modules are assembled together by a mechanical device avoiding infiltration of all the liquid particles and / or solid may be present on each of the modules.

This device is advantageously a seal that is preferably resistant to high temperature and sealed, of the silicone seal type.

As regards the connection of the concavity to the plate, two alternatives can be envisaged: the concavity can be removable or integrated into the plate.

The first alternative may be chosen, for example when the food intended to be cooked and / or heated in the concavity according to the invention are rather of the liquid type.

Those skilled in the art will, according to this alternative, ensure, once the concavity removed from the plate, in particular a seal, as well as a satisfactory electrical insulation in terms of safety, more particularly in compliance with the standards relating to household appliances in force.

Preferably, the concavity according to the invention comprises a flat bottom, advantageously parallel to the plane of the plate. It is thus more convenient to place a cooking vessel in the concavity when it is preferable to do so.

This flat bottom can be advantageously circular. Such a bottom has the advantage of not having any sharp edge detrimental to the ease of cleaning the concavity.

Preferably, this circular flat bottom has a diameter of between 100 mm and 400 mm. Such a range allows the possible use of all the standards of existing cooking vessels.

According to an additional characteristic, the flat bottom may have a transmission in the wavelengths of the visible range T _L and / or infrared T _IR differentiated (s) compared to that which the rest of the plate, of preferably less than 10%.

Such a feature is aesthetically advantageous to the extent that one can impart an appearance to the concavity in contrast with that of the rest of the plate, commonly transparent brown.

According to another characteristic of the invention, the upper peripheral edge is raised relative to the plane of the plate.

According to a further characteristic of the invention, the depth p of the concavity is between 20 mm and 80 mm. With such a characteristic, the cooking appliance retains a correct size and the concavity has a sufficient cooking volume sufficient vis-à-vis the quantity of food (s) to be cooked and / or heated.

According to a preferred variant, the concavity according to the above is covered with a bell. Preferably, this allows vision. It may comprise a glass or glass-ceramic wall. Thus covered, the concavity allows the user to obtain a cooking called "steamed" food contained in the container placed inside the concavity or contained directly in the concavity.

Advantageously, the bell comprises a sheet of ferromagnetic material and at least one inductor is placed under the concavity, preferably in its peripheral part.

Once the heating element and the inductor are in working order, the cooking mode of food is similar to that of a "furnace". Indeed, the food is cooked directly and / or heated by the bottom of the concavity but they are also cooked from above by means of the bell that has become heated by the inductor.

In addition, such a method of cooking is perfectly adapted to new cooking habits. Indeed, it allows a quick and efficient cooking of prepared elements of the type of those who are frozen.

When the concavity does not serve as a heating zone, it can be advantageously covered with a board, the wooden board type. This is preferably of complementary shape over at least a part of the depth of the concavity.

The user of the cooking appliance then has a work surface on which the food can be directly prepared.

Such an "integrated" worktop saves space in the kitchen since the user does not need to provide inside a specific place for food preparation.

The cooking appliance which has just been described is perfectly suitable for constituting a hob or part of a stove.

• figure 1 : une table de cuisson conforme à l'invention intégrée au mobilier de cuisine ;
• figure 2a : une vue en coupe selon l'axe A-A d'une partie de la table de cuisson selon la figure 1 ;
• figure 2b et 2c : une vue en coupe selon l'axe A-A de cette même partie respectivement recouverte d'une cloche et d'une planche en bois.

Other details and advantageous features of the invention will emerge below from the description of an illustrative but nonlimiting exemplary embodiment, with reference to the figures which represent:

• figure 1 : a hob according to the invention integrated in the kitchen furniture;
• figure 2a : a sectional view along the axis AA of a part of the hob according to the figure 1 ;
• Figure 2b and 2c : a sectional view along the axis AA of the same part respectively covered with a bell and a wooden board.

On the figure 1 is shown a cooktop 1 integrated kitchen furniture 2. This cooktop 1 comprises a ceramic hob 3, essentially flat and smooth, resting on a metal frame 4 on which are fixed four cooking hob 5 , elements represented in part on the figure 2 .

The glass ceramic hob 3 consists of two juxtaposed modules 6, 7 assembled together by a silicone seal 8, resistant to high temperature and sealed.

The first module 6 has an integrated concavity 9, adjacent to which is a flat and circular heating zone delimited, in a manner known per se, by a line of white enamel 11. It also has in its marginal part keys sensitive 12, that is to say actuated by the approach of a finger. The sensor keys 12 constitute the respective control means of the four cooking heaters 5 fixed under the plate 3. The second module 7, meanwhile, also comprises a circular and planar heating zone 13 and an opening 14 in which is inserted a gas burner constituting one of the four cooking hobs 5. Around the opening 14 are distributed three bosses 141, 142, 143 for supporting a cooking vessel whose content is to be heated by the burner 15. These bosses are obtained according to the technique described in the patent application WO 97/00407 .

The other cooking heaters 5 consist on the one hand of two heating elements, not shown, each comprising a halogen lamp placed respectively under the two flat and circular heating zones 10, 13 and a heating element 5, shown in FIG. figure 2 constituted by an electrical resistor 16 in the form of a set of conductive wires 17.

The figure 2 is a sectional view along the axis AA of the concavity 9 integrated in the first module 6 above. This concavity 9 comprises a flat bottom 18, parallel to the plane of the plate 3 and of circular diameter and of the order of 300 mm. The depth p of the concavity 9 is approximately equal to 50 mm. Its upper peripheral edge is elevated with respect to the plane of the plate 3.

Immediately under the flat bottom 18 of the concavity 9 is placed an electrical resistor 16 in the form of a set of cylindrical conductive metal wires 17 arranged such that, once supplied with current, it heats homogeneously the entire circular surface of said background 18.

This set of metal wires 17 is fixed to a support of ceramic material 19, itself being mounted in the metal frame 4 of the hob 1.

At the lower periphery of the concavity is mounted tightly with the ceramic support 19 an inductor 20.

On the figure 2b it is seen that the concavity is covered with a bell 21 which has an outer wall 22 glass-ceramic and inside a sheet of ferromagnetic material 23 allowing vision through its opening 24. The sheet of ferromagnetic material 23 constitutes the other part of the induction heating means completed by the inductor 20.

During its design, those skilled in the art will ensure that its structure is such that once the inductor 20 in working condition, the currents flowing through it, called "warm-up", are sufficient to ensure a minimum heating power inside the enclosure delimited precisely by the bell 21 and the concavity 9.

In particular, it will ensure for ease of industrial manufacture and mounting inside the bell 21 to make this plate 23 in one piece.

The cooking mode of this set is "free" and depends on whether the electrical resistance 16 and the inductor 20 are put into simultaneous state or not.

The Figure 2c finally, shows that when none of these elements 16, 20 is in working order, the concavity can be covered with a wooden board 25 of complementary shape over a height h of 30 mm.

To validate the direct cooking function obtained according to the invention, various cooking attempts were made for several types of food placed directly in the concavity 9, using exclusively the electrical resistance 1 6.

Table 1 below indicates, for each type of food, the range of temperatures established to cook in ° C and the time required in min.

When oil has been used to cook the food, this is indicated in parentheses. <u> TABLE 1 </ u> Examples Types of food Range of cooking temperature (° C) Time required for cooking (min) 1 Pork Escalope (Oil) 350-400 6 min for 150 g of meat 2 Pork cutlet 350-400 6 min for 150 g of meat 3 Leg of lamb (Oil) 350-400 8 min for 200 g of meat 4 Ground beef (Oil) 350-400 6 min for 150 g of meat 5 Chopped steak 350-400 6 min for 150 g of meat 6 Chipolatas (Oil) 210-250 20 min for 6 sausages 7 chipolatas 210-250 20 min for 6 sausages 8 Tomato (Oil) 250-280 12 to 18 minutes for 8 washers 9 Tomato 250-280 12 to 18 minutes for 8 washers 10 Onions (Oil) 250-280 18 min for 4 washers 11 Onions 250-280 18 min for 4 washers 12 pancakes 200 3 to 4 minutes per pancake

The concavity was then cleaned after three firings of the same type of food, except for the chipolatas where the cleaning was done after each cooking of 6 sausages.

The products used are, first of all, a product commonly used to clean the dishes and the product marketed under the trade name "Kiraviv" usually used for cleaning glass-ceramic plates.

Along with cleaning, the severity index for each type of food has been raised. This index is representative of the difficulty of cleaning the food and therefore its ability to stain.

It is specified here that, the more difficult the cleaning operation, the higher the severity index.

It is also specified that the severity indices were recorded after cooking 20 kg of each type of food.

Table 2 below lists, for the same types of foods as those in Table 1, the cleanings undergone as well as the severity index. <u> TABLE 2 </ u> Examples Product (s) used for cleaning Severity index 1 Kiraviv then dishes 0.03 2 Kiraviv then dishes 0.03 3 Kiraviv then dishes 0.03 4 Kiraviv then dishes 0.03 5 Kiraviv then dishes 0.03 6 Kiraviv then dishes 0 7 Kiraviv then dishes 0 8 Washing up 0 9 Washing up 0 10 Washing up 0 11 Washing up 0 12 Washing up 0

Reading these tables, it is clear that direct cooking food on a ceramic hob proposed by the invention and cleaning related thereto do not pose a problem.

Of course, it goes without saying that various modifications can be made without departing from the scope of the invention.

Thus, the inductor 20 can be replaced by a heating element and thus allow cooking rather like "steam".

Claims (19)

1. Cooking appliance (1) comprising at least one substantially flat upper plate (3) made of glass-ceramic material and at least one heating element calibrated to a maximum temperature of the order of 450°C or at least one inductor (5, 16, 17), this plate having at least one concavity (9) made in the plate and in the same material, this concavity being placed above said heating element or inductor and being provided in such a way that food or cooking utensils are placed directly in this concavity.
2. Appliance according to claim 1, characterized in that it is coupled with two temperature limiters that are activated respectively at a maximum temperature of the order of 400°C and 580°C.
3. Appliance according to either of claims 1 or 2, characterized in that said heating element is regulated by a thermostat.
4. Appliance according to one of claims 1 to 3, characterized in that said heating element has an annular shape and is placed in a peripheral part under the concavity.
5. Appliance according to any one of the preceding claims, characterized in that the plate additionally includes at least one opening (14) in which there is inserted a gas burner (15) of the atmospheric type and/or at least one flat heating zone (10, 13) under which another heater is placed, such as a heating element or an induction heater.
6. Appliance according to claim 5, characterized in that the plate consists of at least two juxtaposed modules (6, 7), one of the two modules (6) having at least one concavity (9), the other having at least one opening (14) and/or at least one flat heating zone (13).
7. Appliance according to claim 6, characterized in that said modules are assembled together by a mechanical device preventing infiltration.
8. Appliance according to claim 7, characterized in that said mechanical device preventing infiltration is a seal (8), preferably resisting high temperatures and leakproof, of the silicone seal type.
9. Appliance according to any one of the preceding claims, characterized in that the concavity is detachable or integrated in the plate.
10. Appliance according to any one of the preceding claims, characterized in that the concavity has a flat bottom (18), advantageously parallel to the plane of the plate.
11. Appliance according to claim 10, characterized in that the flat bottom (18) of the concavity is circular, preferably with a diameter of between 100 mm and 400 mm.
12. Appliance according to claim 10 or 11, characterized in that the flat bottom has a transmission in wavelengths in the infrared region T_IR and/or the visible region T_L, differentiated with respect to the remainder of the plate, preferably lower by at least 10%.
13. Appliance according to any one of the preceding claims, characterized in that the upper peripheral edge is raised relative to the plane of the plate.
14. Appliance according to any one of the preceding claims, characterized in that the depth p of the concavity lies between 20 mm and 80 mm.
15. Appliance according to any one of the preceding claims, characterized in that the concavity is covered with a lid (21), which may preferably be seen through (24).
16. Appliance according to claim 15, characterized in that the lid has a wall made of glass or glass-ceramic (28).
17. Appliance according to claim 15 or 16, characterized in that the lid includes a sheet of ferromagnetic material (23) and in that at least one inductor (20) is placed under the concavity (9), preferably in its peripheral part.
18. Appliance according to any one of claims 1 to 14, characterized in that the concavity is covered with a board (25), preferably with a complementary shape over at least part of the depth of the concavity.
19. Appliance according to any one of the preceding claims, characterized in that it constitutes a cooktop or part of a cooker.

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