FR3113358A1 - Kitchen utensil for induction hob with magnetic flux modulation - Google Patents

Abstract

Kitchen utensil for induction hob with modulation of the magnetic flux The invention relates to the field of kitchen utensils or containers for induction hob. The kitchen utensil or container (U) for an induction hob (PC) according to the invention has a bottom (F) which comprises a layer of magnetic material (F1) and which is raised with respect to its highest level. bottom, that of the base (B) which is added. The base (B) is composed of a central part (BC) and a peripheral part (BP) and comprises a magnetic material such as magnetic stainless steel or ferrite. The kitchen utensil or container (U) comprises an autonomous means of modulating the transmission of a magnetic flux in its base (B) to control the heating produced on the bottom (F, F1) by the induction coil ( BI) of the cooking plate (PC). Figure to be published with abstract: Fig. 4.

Description

Kitchen utensil for induction hob with magnetic flux modulation

FIELD OF THE INVENTION TO WHICH THE INVENTION RELATES

The invention relates to the field of kitchen utensils or containers for induction hobs.

PRIOR ART

When preparing a dish in a microwave oven, the electrical energy consumed is essentially devoted to cooking the liquid or solid food contained in a container. In this case, the electrical energy consumed is not used directly to heat the container or the oven itself.

In the case of a cooking appliance comprising one or more induction plates, the creation of heat is done by the magnetic field which heats the magnetic elements such as magnetic stainless steel present in the kitchen utensil or the container. .

As depicted , the bottom (F) of the cooking utensil or of the container, in this case a frying pan, comprises several layers. The first layer (F1) is a layer of magnetic stainless steel which will create the heat, the second layer (F2) is a layer of aluminum which will diffuse the heat created, the third layer (F3) will be in contact with the food and will be made of non-magnetic stainless steel.

The induction coil (BI) will generate an electromagnetic field which will heat the magnetic elements by eddy current, in this case the layer (F1).

In doing so, the heating of this layer (F1) will be transmitted not only via its upper face to the food contained in the utensil (U) but also via its lower face to the vitroceramic plate (V) which usually covers the plate induction cooking.

Compared to cooking in a microwave oven, the induction cooking solution not only devotes energy directly to heating the food, energy to heating the kitchen utensil or container but also energy to heat the ceramic hob (V) which supports the kitchen utensil or the container (U).

In addition, once the contents of the cooking utensil or container have been heated, the bottom of the cooking utensil or container is too hot for it to be placed on a table without a trivet.

The aim of the present invention is to reduce the energy loss of the hob dedicated to heating the ceramic hob which supports the kitchen utensil or the container without any use.

In addition, the ceramic hob no longer has a heat dissipation function and the induction hob can be installed under a worktop, for example in melamine or solid wood.

BRIEF DESCRIPTION OF THE INVENTION

The kitchen utensil or the container for an induction hob according to the invention has a bottom which comprises a layer of magnetic material and which is raised with respect to its lowest level, that of the base which is added, corresponding at the location of the ceramic hob.

The bottom (F) is raised by several millimetres.

Preferably, the surface of the base represents at most 25% of the surface of the bottom.

According to a first embodiment, the base (B) is an insulating material which has no magnetic property.

According to a second embodiment, the base comprises a magnetic material, such as martensitic stainless steel, grade 440C.

According to a third embodiment, the base comprises a soft magnetic material.

Preferably, to avoid heat transmission, the soft magnetic material of the base is spaced from the bottom by an air gap.

Advantageously, the soft magnetic material comprises ferrite.

The kitchen utensil or the container can be, for example, a frying pan or a saucepan.

In terms of use, the kitchen utensil or the container according to the invention has the advantage, after having heated its contents, of being able to be placed on a table without having to use a trivet.

The cooking set according to the invention comprises at least one kitchen utensil or container according to the invention, at least one induction cooking plate comprising an induction coil and a plate positioned between a kitchen utensil or container and a coil (BI), in a material that cannot withstand temperatures exceeding 100°C.

Preferably, the cooking assembly comprises luminous means directed from the top towards the location of each of the plates.

Preferably, the cooking assembly includes a means of measuring the temperature of the food from the top downwards

Preferably, the cooking assembly comprises a control panel for the induction hob with its control buttons and its displays placed at a height greater than the level of the location of the induction hobs.

In terms of use, the kitchen utensil or container according to the invention can be heated by induction on a plate in a material that cannot withstand heat above 100° C., below which the coil is installed. induction hob induction.

In terms of use in a restaurant, it is advantageous for the kitchen utensil or container to be placed with its heated contents on a table incorporating at least one induction hob.

In addition, in this context, it is advantageous for the kitchen utensil or container to include a means of informing the user of its temperature. This can be achieved by using a thermochromic material, typically high temperature silicone, at least able to withstand a temperature of 200°C.

Furthermore, in order to be able to adjust a temperature of use, it is advantageous for the kitchen utensil or container to comprise a means of modulating the transmission of a magnetic flux in its base to control the heating produced on the bottom by the coil induction hob.

A simple way to achieve this is to increase the distance between the induction coil of the hob and the bottom, in particular by increasing the height of the base of the kitchen utensil or container.

It is preferred that the modulation of the transmission of a magnetic flux in the base takes place at a constant base height.

According to one embodiment, the modulation of a magnetic flux is done by a variable covering of sectors in magnetic material similarly to a variable air capacitor.

According to one embodiment, the modulation is obtained automatically mechanically by dilation effect.

According to one embodiment, the modulation is obtained automatically electronically by an electric actuator.

It is also advantageous for safety that the kitchen utensil or container comprises a mobile magnetic material in the center of its base and that it has a means for moving it so that in its absence, the cooking plate induction cooker no longer detects the presence of a kitchen utensil suitable for induction cooking and switches off for safety.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings.

shows an induction hob pan in a classic configuration.

shows a frying pan for an induction hob according to the invention where the base is made of insulating material.

shows a frying pan for an induction hob according to the invention where the base is made of magnetic material.

shows a frying pan for an induction hob according to the invention where the base is made of a soft magnetic material.

shows a plate for an induction hob according to the invention where the base is made of soft magnetic material.

shows a frying pan for an induction hob according to the invention where the base is made of soft magnetic material operating on a work surface incorporating an induction hob fitted underneath.

shows a frying pan for an induction hob according to the invention where the base is made of soft magnetic material operating on a work surface integrating elements of soft magnetic material to transmit the magnetic flux of the induction hob installed below.

shows a device integrating four infrared temperature sensors allowing on the one hand to visualize by a light ray the location of the cooking plates and on the other hand to measure the temperature of the utensils including the temperature at their surface of the food in cooking class.

DETAILED DESCRIPTION OF THE INVENTION

The kitchen utensil or the container (U) for an induction cooking plate (PC) according to the invention has a bottom (F) which comprises a layer (F1) of magnetic material and which is raised with respect to its highest level. lower, that of the base (B) which is added, corresponding to the location of the ceramic hob (V).

The bottom (F) is raised by several millimetres.

The base (B) can correspond to the entire surface of the bottom of the kitchen utensil or the container (U) which makes it possible to protect the user from the underside of the bottom (F) which can be hot.

Preferably, the surface of the base (B) represents at most 25% of the surface of the bottom (F) to limit the heat exchange with the glass-ceramic plate (V).

According to a first illustrated embodiment , the base (B) is an insulating material which has no magnetic property.

This material can be a plastic material or silicone compatible with a temperature level of the order of 200° C. to 250° C., materials already used in current kitchen utensils, in particular in the form of high temperature seals.

According to a second embodiment illustrated , the base (B) comprises a magnetic material, such as martensitic stainless steel, grade 440C.

This embodiment has the advantage of being simple to implement since it involves modifying the shape of the bottom (F) in a material identical to that of the magnetic material of the layer (F1).

To reduce the air gap effect added by several millimeters between the induction coil (BI) and the layer (F1), the base (B) has two parts.

The first part is a central part used to channel the magnetic flux from the middle of the induction coil. Typically this central part is part of a circle with a diameter of 5 cm, the size of the central empty space of an induction coil.

The second part is a peripheral part which will also channel the peripheral magnetic flux of the induction coil (BI). Its thickness will be a few millimeters.

If the solution is simple to implement, it has the disadvantage that the base (B) comprising a magnetic material will heat up and lead to a small loss of electrical energy.

On the other hand, this variant remains compatible with a temperature measurement in the center of the kitchen utensil or the container (U) by the cooking plate (PC).

According to a third embodiment, the base (B) comprises a soft magnetic material instead of the preceding magnetic material. This soft magnetic material will channel the magnetic flux without the heating associated with eddy currents.

Preferably, to avoid heat transmission, the soft magnetic material of the base (B) is spaced from the bottom (F) by an air gap.

These soft magnetic materials are those used in transformers.

Advantageously, the soft magnetic material comprises ferrite. It can be molded ferrite which can be fragile or ferrite integrated in a plastic material such as plasto-ferrite.

The kitchen utensil or the container (U) can be, for example, a frying pan or a saucepan.

In terms of use, the kitchen utensil or the container according to the invention has the advantage, after having heated its contents, of being able to be placed on a table without having to use a trivet.

Therefore, it is advantageous to also create new kitchen utensils or containers based on flat-bottomed containers such as plates, large cups or mugs, the bottom of which is made magnetic in the raised position.

In terms of use, the kitchen utensil or container (U) according to the invention also has the advantage of being able to be heated by induction on a work surface (PT) for example in melamine which does not support the heat at the -above 100°C, below which the induction hob (PC) is installed.

Indeed, due to the design according to the invention, the heating by induction of the magnetic metal layer of the bottom (F) is transmitted only in a limited way downwards, that is to say the bearing surface which usually is a glass-ceramic hob (V), it becomes possible to use other materials such as melamine or solid wood from which kitchen worktops are made.

According to a first illustrated embodiment , the induction hob (PC) is recessed under the worktop (PT). In fact, the worktop replaces a ceramic hob (V).

Because the thickness of the worktop above the induction coil (BI) is similar to that of the ceramic hob (V) typically around 5 mm, the induction hob (PC) will operate similarly to a conventional hob (PC).

For it will be impossible to use a conventional induction frying pan because the bottom (F) of the frying pan (U) can be heated to 190°C for example to sear meat, which would destroy most of the materials used for a kitchen work.

In the case represented according to the invention , the bottom (F) of the frying pan (U) is raised, which makes it possible to reduce the transmission of heat downwards towards the bearing surface of the induction hob (PC) and therefore allows materials which, for example would only withstand up to 70°C or 100°C.

The height of the base (B) as well as its constituents in the form of non-metallic non-magnetic insulating materials (BI), soft magnetic material, heat shield materials or vacuum is to be optimized according to the specification of the material. of the worktop, mainly its resistance to heat.

According to a second embodiment illustrated , the induction hob (PC) is installed under the worktop (PT). In fact, the worktop replaces a ceramic hob (V) but with a thickness between 2 and 5 cm, typically with values of 2.8 or 3.8 centimeters.

In this context, it is unlikely that with this distance of several centimeters, a conventional hob can work.

In the case represented according to the invention , to fill the space separating the induction coil (BI) from the utensil (U), the worktop incorporates elements in soft magnetic material in the central part (PTC) and in the peripheral part (PTP) in manhole of the induction coil (BI) so as to transmit the magnetic flux generated by the induction coil to the utensil (U) without heating heat.

In both cases of Figures 6 and 7, the invention has the advantage in a kitchen of having a uniform and aesthetic work plan.

Aesthetic requirements can then lead to the cooking plate(s) not being visible, nor their locations either.

There illustrates a response according to the invention to this problem.

A way is proposed to visualize the location of the cooking plates (PC) by means of light directed from above towards the location of each of the induction cooking plates (PC).

Advantageously, this luminous means is only implemented if the cooking plate or plates are supplied with electric current.

In the illustrated embodiment , these light means are in fact coupled with infra-red (IR) sensors.

On the one hand these sensors (IR1, IR2, IR3, IR4) have the possibility of emitting a light ray towards the measured location and on the other hand of measuring the temperature of the surface encountered. The respective paths (R1, R2, R3, R4) are represented, that of the light emitted in the visible from the infrared sensor (IR) towards the location of the plate just like that of the infrared radiation emitted by the surface of the work surface (PT), of the utensil (U) or of the food (A) towards the infrared sensor (IR), the two paths being substantially identical.

Insofar as certain induction hob (PC) models have a set point mode by temperature regulation, the conventional temperature measurement from below no longer works due to the thermal insulation sought and the temperature measurement of the temperature of the upper surface according to the invention provides a technical alternative.

In addition, the device (D) which integrates the light means directed from the top towards the location of each of the plates as well as a means of measuring the temperature of the food (A) from the top downwards, can advantageously integrate the facade control of the induction hob (PC) with its control buttons and its displays.

Finally, for a restaurant, it can be advantageous in terms of use for the kitchen utensil or container (U) to be placed with its heated contents on a table incorporating at least one induction cooking plate (PC).

In addition, in this context, it is advantageous for the kitchen utensil or container (U) to include a means of informing the user of its temperature. It may be a question on the one hand of reassuring the user that the kitchen utensil or container (U) is sufficiently hot but on the other hand that it is not too hot, in particular at its base. at the risk of burning the user or damaging the support on which it is placed.

This can be achieved by the use of a thermochromic material typically high temperature silicone. Compared to a frying pan whose bottom must be around 190°C to 200°C to sear meat, there are materials such as silicone which in the standard version withstands up to 200°C, in the high temperature version up to at 250°C, or even in the very high temperature 300°C version.

There are also versions of thermochromic silicones with the possibility of choosing the temperature and transition color, programmable 3 colors and 3 temperatures.

Furthermore, in order to be able to adjust a temperature of use, it is advantageous for the kitchen utensil or container (U) to comprise an autonomous means of modulating the transmission of a magnetic flux in its base (B) to control the heating produced on the bottom (F, F1) by the induction coil (BI) of the cooking plate (PC).

A simple way to obtain it is to increase the distance between the induction coil (BI) of the hob (PC) and the bottom (F, F1), in particular by increasing the height of the base (B) kitchen utensil or container (U).

For example, the base is in two parts, the lower part screwing onto the upper part. By screwing or unscrewing the lower part, the height of the base increases in proportion to the angle of rotation and the thread pitch.

If magnetic materials are present in the base (B), this leads to modulating the air gaps between these magnetic materials and the bottom (F, F1) or the induction coil (BI) of the hob, or even both simultaneously.

It is preferred that the modulation of the transmission of a magnetic flux in the base (B) takes place at a constant base height (B) in order in particular to take place at low energy without having to lift the kitchen utensil or container (U) weighed down by the weight of the food contained.

According to one embodiment, the modulation of a magnetic flux is done by a variable covering of sectors in magnetic material similarly to a variable air capacitor. At least two sets of magnetic material sectors are superimposed on the periphery with a variable overlap depending on the relative angle of rotation along a vertical axis between the two sets of sectors.

In the center of the base, it may be a telescopic central part made of magnetic material produced by a set of elements similar to a telescopic antenna.

According to one embodiment, the modulation is obtained automatically mechanically by dilation effect. It can be, for example, a bimetallic strip, if necessary wound in a spiral.

According to one embodiment, the modulation is obtained automatically electronically by an electric actuator. This may be the case where the container (U) is the mixing bowl of a food processor, heated directly by the induction coil (BI) of the cooking plate (PC) and where the electronics of the food processor cooker uses an electric actuator to control the magnetic permeability of the base (B) positioned under the mixing bowl.

It is also advantageous for safety that the kitchen utensil or container (U) comprises a mobile magnetic material in the center of its base (B) and that it has a means for moving it so that in its absence, the induction hob (PC) no longer detects the presence of a kitchen utensil suitable for induction cooking and switches off for safety.

In terms of industrial application, the invention applies to kitchen utensils or containers for induction hobs.

The present invention is in no way limited to the embodiments described and represented, but those skilled in the art will be able to add any variant in accordance with their spirit for a range of products.

Claims (24)

Kitchen utensil or container (U) for an induction hob (PC) characterized in that its bottom (F) comprises a layer (F1) of magnetic material and that this bottom (F) is raised with respect to its level the lowest, that of the base (B) added, corresponding to the location of the ceramic hob (V). Kitchen utensil or container (U) according to Claim 1, characterized in that the bottom (F) is raised by several millimeters. Kitchen utensil or container (U) according to any one of Claims 1 to 2, characterized in that the surface of the base (B) represents at most 25% of the surface of the bottom (F). Kitchen utensil or container (U) according to any one of Claims 1 to 3, characterized in that the base (B) comprises a magnetic material. Kitchen utensil or container (U) according to Claim 4, characterized in that the magnetic material is martensitic stainless steel, grade 440C Kitchen utensil or container (U) according to any one of Claims 1 to 4, characterized in that the base (B) comprises a soft magnetic material. Kitchen utensil or container (U) according to Claim 6, characterized in that the soft magnetic material of the base (B) is spaced from the bottom (F) by an air gap. Kitchen utensil or container (U) according to any one of Claims 6 to 7, characterized in that the soft magnetic material comprises ferrite. Kitchen utensil or container (U) according to any one of Claims 1 to 8, characterized in that the kitchen utensil or container (U) is a plate or a large cup. Cooking set characterized in that it comprises at least one cooking utensil or container (U) according to one of Claims 1 to 9, at least one induction cooking plate (PC) comprising an induction coil ( BI) and a plate positioned between a kitchen utensil or container (U) and a coil (BI) in a material that cannot withstand temperatures exceeding 100°C. Assembly according to Claim 10, characterized in that it comprises luminous means directed from the top towards the location of each of the plates. Assembly according to Claim 10, characterized in that it includes a means of measuring the temperature of the food (A) from the top downwards Assembly according to Claim 10, characterized in that it comprises a control panel for the induction cooking plate (PC) with its control buttons and its displays placed at a height greater than the level of the location of the cooking plates (PC ) induction. Use of the kitchen utensil or container (U) according to one of Claims 1 to 9, characterized by the fact of being heated by induction on a plate in a material which cannot withstand heat above 100°C , below which the induction coil (BI) of the induction hob (PC) is installed. Use according to claim 14, characterized by the fact that the kitchen utensil or container (U) is placed with its heated contents on a table incorporating at least one induction hob (PC). Kitchen utensil or container (U) according to any one of Claims 1 to 9, characterized in that it comprises a means of informing the user of its temperature. Kitchen utensil or container (U) according to Claim 16, characterized in that the means of providing information on its temperature is the use at its base (B) of a thermochromic material. Kitchen utensil or container (U) according to Claim 17, characterized in that the thermochromic material is a high temperature silicone. Kitchen utensil or container (U) according to any one of Claims 1 to 9, characterized in that it includes a means of modulating the transmission of a magnetic flux in its base (B). Kitchen utensil or container (U) according to Claim 19, characterized in that the modulation of the transmission of a magnetic flux in its base takes place at a constant base height (B). Kitchen utensil or container (U) according to any one of Claims 19 to 20, characterized in that the modulation of a magnetic flux takes place by a variable covering of sectors in magnetic material. Kitchen utensil or container (U) according to any one of Claims 19 to 20, characterized in that the modulation is obtained automatically mechanically by expansion effect. Kitchen utensil or container (U) according to any one of Claims 19 to 20, characterized in that the modulation is obtained automatically electronically by an electric actuator. Kitchen utensil or container (U) according to any one of Claims 1 to 9, characterized in that it comprises a mobile magnetic material in the center of its base (B) and that it has a means for moving it.