COOKING APPARATUS

Abstract

 Cooking apparatus (10) comprising a cooking plate (12) for cooking foods of various kinds, by positioning them directly in contact therewith and at least one pair of electric heating elements (20) of the resistive type, provided with a printed circuit (21).

Description

FIELD OF THE INVENTION

[0001] The present invention concerns a cooking apparatus for kitchens, preferably professional and/or industrial, comprising a cooking plate on which the foods to be cooked are directly positionable and electric heating elements of the resistive type for heating said plate.

BACKGROUND OF THE INVENTION

[0002] Cooking apparatuses are known comprising a cooking plate heated by electric heating elements of the resistive type.

[0003] Such apparatuses are also known by the term "frytop" and are frequently used in professional and/or industrial kitchens, as they allow food to be cooked directly on the cooking plate, without the use of pans or other.

[0004] In general, the cooking plate comprises an upper side in view, on which the food to be cooked is placed, and a lower side, usually made of soft iron. The upper side of the plate may or may not have a surface treatment of glossy chrome plating, or satin chrome plating.

[0005] The electric heating elements are placed below the cooking plate, close to or in contact with the lower side of the cooking plate, and the heat generated by them is transmitted to the upper side by conduction.

[0006] The cooking plate is continuously welded on an upper worktop of the equipment, thus preventing liquids and fats from drawing and ensuring a certain structural solidity. In such known cooking apparatuses, the electric heating elements of resistive type can be:

• armoured, of circular or triangular cross-section;
• exposed filament, also known as infrared resistors;
• electromagnetic induction generators.

[0007] US 10,440,781 discloses a thick layer heating element which comprises a planar substrate coated on one of its faces with an electrically resistive layer connected to an electrical contact area. A dielectric layer is interposed between the planar substrate and the resistive layer. A conductive layer and an insulating layer can also be deposited to cover the resistive layer.

[0008] WO 2020094949 discloses a heating system for cooking appliances comprising a cooking plate having a lower surface, heating means positioned below the cooking plate and facing the lower surface, in which the heating means comprise a heat diffuser resting on the lower surface of the cooking plate and extending in a direction opposite thereto.

[0009] WO 2012076392 also discloses a cooking system having a heating element associated below with a cooking plate.

[0010] One of the disadvantages of such known cooking apparatuses is that frequently the heat exchange surface between the electric heating elements and the cooking plate is not optimized.

[0011] For example, if resistive-type armoured electric heating elements of circular, or triangular section are used, the heat exchange surface is linear, therefore not homogeneous, or it is limited to a small portion of the outer surface of the heating elements.

[0012] Furthermore, another disadvantage of the known cooking apparatuses is the absence of a circumscribed, or sectoral, activation of the electric heating elements; in fact, regardless of whether it is necessary or not, the entire area of the cooking plate is often heated. This also entails the disadvantage of having unoptimized electrical consumption.

[0013] Another disadvantage is the presence of rigid assembly systems which require frequent maintenance as the repeated thermal stresses cause expansion and compression which modify the contact condition between the heating element and the cooking plate.

[0014] Another disadvantage is the frequent need in the known systems to use thermal diffusers to properly convey the heating to the cooking zones.

[0015] There is therefore a need to perfect a cooking apparatus that can overcome at least one of the disadvantages of the state of the art.

[0016] To do this, it is necessary to solve the technical problem of making a cooking apparatus which allows to have an optimized heat exchange surface while simultaneously allowing to reduce electrical consumption.

[0017] In particular, one purpose of the present invention is to provide a cooking apparatus which allows to have a uniform temperature on the upper side of the plate.

[0018] Another purpose of the present invention is to provide a cooking apparatus which allows to optimize the temperature increase time of the cooking plate, consequently reducing the initial ignition times.

[0019] A further purpose of the present invention is to provide a cooking apparatus which is easy to manufacture and which allows to have low production costs, in particular with respect to electromagnetic induction generators.

[0020] The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

[0021] The present invention is set forth and characterized in the independent claim. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

[0022] In accordance with the above purposes, and to resolve the technical problem disclosed above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a cooking apparatus according to the present invention for kitchens, preferably professional, or industrial, comprises at least one cooking plate for cooking foods of various kinds, by positioning them directly in contact therewith.

[0023] In accordance with an aspect of the present invention, said cooking apparatus comprises at least one electric heating element of the resistive type provided with a printed circuit, which is operatively associated with said cooking plate and disposed below it in order to guarantee a homogeneous heat exchange surface over the entire cooking area.

[0024] In accordance with the present invention, the coupling between the heating element and the cooking plate occurs by means of at least one pressure element associated with the heating element by means of at least one elastic element.

[0025] According to another aspect of the present invention, a mechanical pressure distribution and thermal insulation panel is present between the pressure element and the heating element.

[0026] In an embodiment, said distribution panel is made of ceramic fibre.

[0027] In another embodiment, there are at least two pressure elements, advantageously three, in cooperation with the heating element, and with the distribution panel, if present, and they are mounted in use slightly distant from one another, so as to keep an adaptation or compensation light in mounted condition.

[0028] In an embodiment, the elastic element is a cup spring associated with a means for mounting the pressure element on the heating element.

[0029] In accordance with another aspect of the present invention, there are at least two heating elements and they are disposed on opposite sides to each other, preferably specular, with respect to a corresponding axis of symmetry.

[0030] In accordance with another aspect of the present invention, said printed circuit is made in such a way as to be divided into two or more main zones connected to each other.

[0031] In accordance with another aspect of the present invention, said printed circuit is provided, for each of said main zones, with at least one corresponding secondary zone in which the electric power supplied is reduced with respect to the remaining part.

[0032] In accordance with another aspect of the present invention, in said secondary zone said electric power supplied is reduced by 10% - 30%.

[0033] In accordance with another aspect of the present invention, said electric heating elements are disposed specularly so that the respective secondary zones are positioned in correspondence with a respective central part which develops along said corresponding axis of symmetry.

[0034] In accordance with another aspect of the present invention, each electric heating element comprises an upper layer and a lower layer between which said printed circuit is interposed, and are made up of one or more silicate minerals belonging to the mica group.

[0035] In accordance with another aspect of the present invention, said upper and lower layer are made of muscovite and are capable of guaranteeing an effective electrical insulation while maintaining a negligible thermal insulation.

[0036] In accordance with another aspect of the present invention, said upper and lower layers have a thickness comprised between 0.3 mm and 0.7 mm.

[0037] In accordance with a further aspect of the present invention, said electric heating elements are capable of providing a maximum operating temperature of at least 330 °C. Furthermore, in order to guarantee a regular operation of said cooking apparatus, each heating element is connected to a plurality of cables capable of withstanding said temperature.

DESCRIPTION OF THE DRAWINGS

[0038] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

• fig. 1 is a perspective, schematic and simplified view of a cooking apparatus according to the present invention;
• fig. 2 is a schematic and simplified top view of a cooking plate in which the electric heating elements of the cooking apparatus of fig. 1 have been highlighted;
• fig. 3 is a sectional, schematic and simplified view of the electric heating elements of fig. 2;
• fig. 4 shows the cooking apparatus in an exploded condition before assembly;
• fig. 5 shows the cooking apparatus in section after assembly;
• fig. 6, 7 and 8 show some examples of different heating circuits where it is seen how a heating non-uniformity can be obtained on the lower surface of the cooking plate.

[0039] We must clarify that in the present description the phraseology and terminology used, as well as the figures in the attached drawings also as described, have the sole function of better illustrating and explaining the present invention, their function being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

[0040] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.

DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION

[0041] With reference to figure 1, a cooking apparatus 10 according to the present invention is disposed and usable in kitchens, preferably professional, or industrial.

[0042] The cooking apparatus 10 comprises a support structure 11 to which a cooking plate 12 is associated which allows to cook foods of various kinds, such as meat, fish and vegetables, by placing them directly in contact with the cooking plate.

[0043] According to preferred embodiments, the cooking plate 12 is continuously welded to the support structure 11, so that liquids and fats do not draw below it, while ensuring an adequate structural solidity.

[0044] The cooking plate 12 can have different shapes and sizes according to the specific operating needs. Preferably, said plate 12 has a rectangular shape. Said plate 12 comprises an upper side, or surface, 15 in view, on which foods are positionable, and a lower side, or surface, 16 (fig. 3) which is facing the inside of the support structure 11.

[0045] According to the possible embodiments, the upper side 15 (fig. 1) can be totally smooth, or it can have a plurality of ribs, in relation to the type of cooking desired. Alternatively, the upper side 15 can have both a smooth portion and a ribbed portion.

[0046] The cooking plate 12 may be provided with a slot, or a channel, for draining 17 liquids, fats and/or small portions of food, which is disposed towards the user.

[0047] According to possible preferred embodiments, the cooking plate 12 can be inclined at a certain angle towards the drain channel 17 so as to allow the regular drainage of said liquids, fats and/or small portions of food, towards the latter.

[0048] The cooking apparatus 10 comprises at least one pair of electric heating elements 20 (figures 1 and 2) of printed circuit resistive type 21, which are operatively associated with the cooking plate 12 and disposed uniformly below it so as to guarantee a homogeneous heat exchange surface over the entire cooking area. The electric heating elements 20 (fig. 2) are disposed on opposite sides, preferably specular with respect to a corresponding axis of symmetry X.

[0049] According to the possible embodiments, in relation to the dimensions of the cooking plate 12, there may be several pairs of electric heating elements 20 disposed side by side, in which, for each pair, the electric heating elements 20 are disposed specularly with each other with respect to corresponding axes of symmetry X, which are parallel with respect to each other.

[0050] The cooking apparatus is assembled as illustrated in fig. 4. On the lower surface 16 of the cooking plate 12, threaded pins 27 are applied, of sufficient length and diameter to withstand the stresses which are determined during operation and the repeated heating and cooling cycles.

[0051] The heating element 20 is rested on the lower surface 16 of the plate 12. There are three openings, holes or slots, respectively 28a, 28b and 28c, on the heating element 20. The opening 28a, the one closest to the end from which the conductors 29 for the electrical power supply depart, is of circular shape, with a diameter just greater than the diameter of the pin 27. The coupling between opening 28a and respective pin 27 defines the precise positioning of the heating element 20 on the plate 12. The two openings 28b, 28c have an elongated shape in the longitudinal direction to allow the free passage of the other two pins 27. Such a solution allows to take into account the manufacturing tolerances of the components and to absorb the elongation of the plate 12, in particular during operation.

[0052] A distribution panel 30 having dimensions substantially equivalent to those of the heating element 20 is rested on the heating element 20. There are also three openings 31 for the passage of the pins 27 present thereon, which advantageously have the same characteristics described above for the openings 28a, 28b and 28c.

[0053] The panel 30 is made of material suitable to withstand, without degrading, the high operating temperatures of the cooking apparatus 10. In particular, a preferred solution is to use ceramic fibre, with an appropriate thickness and consistency such as to allow a significant compression.

[0054] The panel 30 has the dual function of thermally insulating the heating element 20 from the pressure elements described below, and of extremely uniformly distributing the pressure exerted by the aforesaid pressure elements on the heating element.

[0055] In this case, three pressure elements 32 are then rested on the aforesaid panel 30, whose function is to press the heating element 20 to obtain an intimate contact thereof with the plate 12. Each pressure element 32 is provided with a circular opening 36 having a diameter slightly greater than that of the pin 27 to ensure a precise positioning.

[0056] The longitudinal dimensions of the pressure elements 32 are such as to guarantee an appropriate clearance 33 between adjacent elements, to avoid interference during assembly and operation.

[0057] Such pressure elements 32 are characterized by a high rigidity, necessary to uniformly transmit the pressure on the heating element 20, and a reduced thermal capacity, so as not to weigh down the performance of the heating system with a parasitic inertia.

[0058] Once the pressure elements 32 are disposed in position, a metallic elastic element, for example a cup spring 34, is applied to each pin 27.

[0059] Such metallic elastic elements rest on the pressure element 32 to correctly obtain the force to be applied to the pressure element 32 itself.

[0060] Finally, a nut 35 provided with an appropriate flange is screwed onto each pin 27.

[0061] The nut 35 is screwed to compress the elastic elements 34 until the expected force on the pressure element 32 is developed.

[0062] The use of this non-rigid assembly system does not require the maintenance which is normally required over time in the solution with rigid fixings.

[0063] In one embodiment, each electric heating element 20 comprises two insulating layers 22, 23, respectively an upper layer 22 and a lower layer 23, between which the printed circuit 21 (fig. 3) is interposed.

[0064] The printed circuit 21 (fig. 2) can be configured to ensure maximum temperature uniformity on the upper side 15 of the cooking plate 12. To obtain such temperature uniformity, the printed circuits can be drawn in a non-uniform manner, for example with differentiated resistive line densities on the surface, as in the examples of figs. 6, 7 and 8, so that, depending on the different surface dissipation capacity of the plate, the resulting temperature is thereby uniform.

[0065] In particular, the printed circuit 21 is designed and made so as to be divided into two or more main zones Z1, Z2, Z3 connected to each other.

[0066] According to preferred embodiments, each printed circuit 21 comprises three equally sized main zones Z1, Z2, Z3.

[0067] Furthermore, the printed circuit 21 is provided, for each main zone Z1, Z2, Z3, with at least one corresponding secondary zone ZS1, ZS2, ZS3, in which the electric power supplied is reduced with respect to the remaining part.

[0068] In the example of fig. 6, the zone Z1 has a higher resistive line density with respect to zone Z2, while zone Z3 does not.

[0069] In fig. 7 the solution is similar to that of fig. 6, except that the shape is square and not round.

[0070] Fig. 8 also depicts a solution with differentiated density zones, the heating element 20 being rectangular in shape.

[0071] As mentioned, the use of zones with differentiated density, suitably designed on the basis of the dissipative capacity of the heating element and of the plate associated therewith, allows to obtain a uniform heating temperature on the entire surface of the plate.

[0072] This advantageously allows to reduce the operating electric consumption of the cooking apparatus 10.

[0073] The electric heating elements 20 are advantageously, even if not necessarily, disposed specularly so that the respective secondary zones ZS1, ZS2, ZS3 are positioned at a respective central part PC which develops along the corresponding axis of symmetry X, and in which more heat is usually generated. By doing so, it is desired to avoid the generation of a localized heating in said respective central part PC, so as to ensure a temperature uniformity substantially over the entire upper side 15 of the cooking plate 12.

[0074] If there are several pairs of electric heating elements 20, it is clear that there will also be several central parts PC. It should be specified that the term "central" is used with reference to the respective pair of electric heating elements 20.

[0075] Preferably, the electric power supplied in the secondary zones ZS1, ZS2, ZS3 is reduced by an amount such as to ensure such temperature uniformity. The Applicant has found that such an effect can be achieved with a reduction in electric power, supplied in the secondary zones ZS1, ZS2, ZS3, of approximately 10% - 30%. It should be noted that the specific extent of the reduction in electric power depends on the embodiment of the cooking apparatus 10.

[0076] The layers 22, 23 (fig. 3) comprise, or consist of, one or more silicate minerals belonging to the mica group. Preferably, the upper layer 22 and the lower layer 23 are made of muscovite, a silicate mineral which is capable of guaranteeing an effective electrical insulation while maintaining a negligible thermal insulation. Furthermore, the muscovite has a negligible roughness and the upper layer 22 is adjacent to, or preferably in contact with, the lower side 16 of the cooking plate 12, so as to optimize and maximize the heat exchange by conduction.

[0077] The optimization of the heat exchange has the advantage that it also leads to a decrease in the electric energy needed to heat the cooking plate 12, thus causing a decrease in the environmental impact during the use of the cooking apparatus 10.

[0078] According to preferred embodiments, the two layers 22, 23 may have the same thickness comprised between about 0.3 mm and about 0.7 mm.

[0079] Therefore, the printed circuit 21 having a negligible thickness, the electric heating elements 20 are substantially flat with a very reduced overall thickness of about 1-2 mm. This favours a clear reduction of the thermal inertia and, therefore, a significant decrease in the rise and fall times of the temperature of the heating elements 20 themselves. As a result, there is the advantage of having a decrease in the switching on times of the cooking apparatus 10 and of making it even more reactive during the cooking step.

[0080] Each electric heating element 20 is capable of providing a maximum operating temperature of at least 330°C. Therefore, in order to guarantee a correct and regular operation of the cooking apparatus 10, each heating element 20 is connected to a plurality of pairs of cables 25 (fig. 2) each having, for example, a section of about 1 mm². Each pair of cables 25 is made so as to be able to withstand said temperature. For example, the cables 25 may be nickel-plated cables.

[0081] It should be noted that the fixing between the heating elements 20, the respective upper 22 and lower 23 layers and the cooking plate 12 is obtained by means of rigid brackets, screws and/or springs suitably pre-tensioned to compensate possible deformations of the two layers 22, 23 and designed to facilitate maintenance.

[0082] Furthermore, the cooking apparatus 10 comprises an electromechanical or digital control system, not depicted in the drawings, connected to one or more user interface means 26 (fig. 1) and configured to guarantee both the activation of the electric heating elements 20 and the temperature control of the latter and the cooking plate 12.

[0083] For example, the user interface means can be touch screens, buttons, selection knobs, etc.

[0084] According to embodiments the cooking apparatus 10 is configured to be connectable to a three-phase electric network and be powered at about 380-415 V 3N. Additionally, or alternatively, the cooking appliance 10 is configured to be connectable to a single-phase electric network and to be powered at about 220-240 V.

[0085] By way of non-limiting example, depending on the size of the cooking plate 12, each pair of cables 25 is adapted to provide an electrical power comprised between about 650 W and about 950 W.

[0086] It is clear that modifications and/or additions of parts can be made to the cooking apparatus 10 described heretofore, without departing from the field and scope of the present invention, as defined by the claims.

[0087] It is also clear that, although the present invention has been described with reference to some specific examples, a person skilled in the art shall certainly be able to achieve other equivalent forms of cooking apparatuses, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

[0088] In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

1. Cooking apparatus (10) comprising at least one cooking plate (12) for cooking foods of various kinds, positioning them directly in contact therewith it, characterized in that it comprises at least one electric heating element (20) of the resistive type provided with a printed circuit (21), operatively associated with said cooking plate (12) and disposed below it to ensure a homogeneous heat exchange surface over the entire cooking area, and in that the coupling between the electric heating element (20) and the cooking plate (12) occurs by means of at least one pressure element (32) associated with the electric heating element (20) by means of at least one elastic element (34).

2. Cooking apparatus (10) as in claim 1, characterized in that, between the pressure element (32) and the heating element (20) there is a both thermal and mechanical distribution panel (30).

3. Cooking apparatus (10) as in claim 2, characterized in that said distribution panel (30) is made of ceramic fibre.

4. Cooking apparatus (10) as in one or the other of the preceding claims, characterized in that there are at least two pressure elements (32), in cooperation with the heating element (20), and are mounted in use slightly distant from each other, so as to maintain an adaptation or compensation light (33) in a mounted condition.

5. Cooking apparatus (10) as in one or the other of the preceding claims, characterized in that the elastic element is a cup spring (34) associated with a mounting means (27) of the pressure element (32) on the electric heating element (20).

6. Cooking apparatus (10) as in one or the other of the preceding claims, characterized in that the electric heating elements (20) are two and are disposed on opposite sides to each other, preferably specular, with respect to a corresponding axis of symmetry (X).

7. Cooking apparatus (10) as in one or the other of the preceding claims, characterized in that said printed circuit (21) is made in such a way as to be divided into two or more main zones (Z1, Z2, Z3) connected to each other.

8. Cooking apparatus (10) as in claim 7, characterized in that said printed circuit (21) is provided, for each of said main zones (Z1, Z2, Z3), with at least one corresponding secondary zone (ZS1, ZS2, ZS3) in which the electric power supplied is reduced with respect to the remaining part.

9. Cooking apparatus (10) as in claim 8, characterized in that in said secondary zone (ZS1, ZS2, ZS3) said electric power supplied is reduced by 10% - 30%.

10. Cooking apparatus (10) as in claim 8 or 9, characterized in that said electric heating elements (20) are disposed specularly so that the respective secondary zones (ZS1, ZS2, ZS3) are positioned in correspondence with a respective central part (PC) which develops along said corresponding axis of symmetry (X).

11. Cooking apparatus (10) as in any claim hereinbefore, characterized in that each electric heating element (20) comprises an upper layer (22) and a lower layer (23) between which said printed circuit (21) is interposed, and which are made up of one or more silicate minerals belonging to the mica group.

12. Cooking apparatus (10) as in claim 11, characterized in that said upper (22) and lower (23) layer are made of muscovite.

13. Cooking apparatus (10) as in claim 12 or 13, characterized in that said upper (22) and lower (23) layer have a thickness comprised between 0.3 mm and 0.7 mm.

14. Cooking apparatus (10) as in any claim hereinbefore, characterized in that said electric heating elements (20) are capable of supplying an operating temperature of at least 330°C, and in that each heating element (20) is connected to a plurality of cables (25) capable of withstanding said temperature.

Drawing