EP3490340B1 - Method for inductively heating an inductively heatable cooking vessel, transmission coaster and induction heating cooker for carrying out the method - Google Patents

Description

AREA OF APPLICATION AND STATE OF THE ART

The invention relates to a method for inductively heating an inductively heatable cooking vessel. In particular, the invention is about being able to heat an inductively heatable cooking vessel in such a way that it can be done independently of a base. The invention also relates to a transfer coaster on which the cooking vessel can be placed for heating, and an inductive cooking device for carrying out the method.

From the WO 2013 / 103939A1 an inductive cooking appliance is known in principle, which enables the inductive heating of a cooking vessel placed on it by means of a transfer coaster. The transfer coaster keeps the heat generated by the cooking vessel from the base or surface on which it is placed. This can consist of new materials such as wood, which would otherwise not withstand the temperatures that arise during inductive cooking without damage.

From the DE 103 15 217 A1 a hob is known with a display which can provide an operator with information in a simple manner as to whether a pot is placed centered or shifted with respect to a heating device arranged under a hob plate. This allows an operator to move the pot into a better position.

From the DE 10 2010 020 189 A1 such a transmission divider is known as mentioned above. A lower induction coil and an upper induction coil, which are connected by a common circuit, are arranged in the transmission reducer. An electronic assembly with a sensor for detecting the temperature of an attached cooking vessel or for determining the weight can be provided on the transmission coaster.

From the WO 2017/052282 A1 it is known to provide a support coaster on a base below which an induction heating coil is arranged. The support coaster has a plate 20 and an operating unit 30. An alternating magnetic field for inductive heating of an attached cooking vessel goes directly through the support plate.

From the EP 2 385 312 A2 shows a mobile control unit for an inductive cooking device. This control unit can be placed on one of several induction heating coils in order to use Energy to be supplied. In this way, the operation of further induction heating coils can be controlled, in particular for heating cooking vessels that are placed on these induction heating coils.

TASK AND SOLUTION

The invention is based on the object of creating a method mentioned at the beginning, a transmission coaster and an inductive cooking device for carrying out the method, with which problems and disadvantages of the prior art can be avoided and in particular it is possible to create a practical method which can be achieved with the inductive heating of a cooking vessel by means of a transfer coaster optimal operation and efficiency.

This object is achieved by a method with the features of claim 1, by a transmission coaster with the features of claim 11 and by an inductive cooking device for performing this method with the features of claim 13. Advantageous and preferred embodiments of the invention are the subject of the further claims and are explained in more detail below. Some of the features are only described in connection with the method, the transmission reducer or the inductive cooking appliance. However, they should be able to apply independently and independently of one another both to the method and to the transmission reducer and for the inductive cooking appliance. The wording of the claims is made part of the content of the description by express reference.

The inductive cooking device has at least one primary induction coil, a cover, which is in particular flat, over the primary induction coil, a power supply for the primary induction coil, and a cooking device control that is connected to the power supply. Furthermore, it has at least one transfer coaster, which is particularly flat and planar, the transfer coaster being freely movable independently of the cooking appliance so that it can be placed in any position on the cover above the primary induction coil. The transfer reducer has at least one resonant circuit with at least one resonant circuit coil and at least one resonant circuit capacitor in order to transmit inductive power from the primary induction coil via the resonant circuit into the cooking vessel placed on the transfer reducer.

According to the invention, a display is provided for an operator to indicate whether or not the transfer reducer is optimally positioned above the primary induction coil. In this way, the energy transfer can be optimized and stray fields can be avoided. In the method for inductively heating an inductively heatable cooking vessel by means of at least one induction coil of the inductive cooking appliance, the following steps are carried out. Initially, a position of the transmission reducer relative to the primary induction coil is detected, which can be done in particular with regard to the optimal and / or central position of the oscillating circuit coil in relation to the primary induction coil. If the position deviates by more than a limit distance from a predetermined optimal position, information can be given to the operator on the display as to the direction or how the transmission reducer is to be moved in order to bring it into the optimal position . The optimal position is advantageously a single point or a circle around it with a small radius, for example 1 cm to 5 cm, advantageously up to 2 cm. In the optimal case, the transfer reducer is placed exactly above this point or circle, i.e. centrally to it. The limit distance can be specified either absolutely in cm or relative to an approximate diameter of an installed transfer coaster, for example 5% to 20% of the diameter.

The operator can thus be helped with the display to position the transmission coaster as well or optimally as possible over the induction coil of the inductive cooking appliance, even if there is no marking on the surface or top of the inductive cooking appliance. As a result, such an inductive cooking device can advantageously have a normal table surface, for example made of wood, linoleum or with a plastic coating, which otherwise would not be usable due to thermal problems or only with the risk that their appearance is negatively affected by excessively high temperature due to being hot set up cooking vessel.

In an embodiment of the invention, the optimal position and / or the limit distance can be permanently specified, in particular programmed in at the factory. Under certain circumstances they can be changed by an operator. Alternatively, they can be programmed to be unchangeable.

The limit distance can be 1 cm to 10 cm, advantageously 2 cm to 5 cm. Alternatively, it can be at least 5% of the maximum diameter of the transfer reducer, preferably at least 5% to a maximum of 100% of the maximum diameter of the transfer reducer, in particular 10% to 25%.

The best possible placement can be achieved if the resonant circuit coil of the transmission reducer is preferably in the optimal position centered on the primary induction coil. Then even their sizes can be coordinated so that the transmission is optimal.

In one embodiment of the invention, the display is integrated in the transmission coaster itself, in particular as a lighted display and / or with light-emitting elements. In this way it can be seen directly on the transmission coaster how it is placed or how it can or must be better placed. If this is done directly when putting on the transfer coaster, it is particularly intuitive. The luminous display can then have luminous elements, which are preferably arranged at a distance from one another on different outer areas or outer sides of the transmission coaster. It is possible here for lighting elements to be arranged on four opposite sides of the transfer coaster, that is to say at least four lighting elements in total. By activating a light-emitting element, an operator can then be given the information that the transmission reducer is to be moved in a direction corresponding to this light-emitting element from its center point towards this light-emitting element in order to reach the optimum position. If the light-emitting elements are arranged close to or directly on the edge of the transfer coaster, they can be intuitively understood by an operator as a directional indicator. It is then also possible to indicate that this optimum position has been reached after moving the transfer reducer by flashing or changing the light of one or more light elements, in particular all light elements.

During the movement of the transmission reducer to reach the optimal position, at least one flashing light element, in the direction of which the transmission reducer is being moved, can indicate by increasingly faster flashing when the transmission reducer approaches the optimal position in this direction. When reaching the optimal position in this direction, this light-emitting element can change from blinking to constant lighting. An operator can then see from the constant lighting that a stable and as permanent as possible state has now been reached.

Alternatively, it can be provided that while moving the transmission coaster to reach the optimal position, at least one flashing light element, in the direction of which the transmission coaster is being moved, indicates by increasingly brighter flashing when the transmission coaster is approaching the optimal position in this direction. The blinking changes again, only this time it gets brighter instead of faster. When the optimum position is reached in this direction, this lighting element can then change from blinking to constant lighting, which in turn can indicate a state that is as permanent as possible.

Again, alternatively, it can be provided that while the transmission coaster is moving to reach the optimal position, at least one permanently illuminated luminous element, in the direction of which the transmission coaster is being moved, indicates by increasingly brighter lighting when the transmission coaster approaches the optimal position in this direction . When the optimum position is reached in this direction, this light element can change from constant lighting to flashing with the last set brightness, or alternatively also to flashing with a different brightness. This flashing can be limited to a few seconds, preferably 2 seconds to 10 seconds.

In an alternative embodiment of the invention, the display can be arranged on a separate external device separate from the inductive cooking device and the transmission coaster, in particular on a mobile terminal device such as a mobile phone, a tablet computer or on a television or a display. The display can have luminous elements as direction markers in four different evenly distributed directions, similar to that described above when the display is arranged on the transmission coaster itself. By activating a light-emitting element, an operator can in turn be given the information to move the transmission reducer in the direction of the direction marker of this light-emitting element in order to reach the optimum position. Only in this case the display is not provided on the transmission reducer itself but on the external device. Here, too, by changing the behavior of the light elements, as described above, preferably by flashing one or more light elements, in particular all light elements, the reaching of the optimum position can be indicated. The direction markers or corresponding luminous elements can use arrows to indicate to the operator in which direction the transfer reducer is to be moved.

Similar to what was described above for the display and light elements in the transmission coaster, the display and light elements on the external device or in the inductive cooking device can be used to show in principle the same visual representation as the transmission coaster is to be moved in order to be optimally and appropriately placed.

While moving the transmission coaster to reach the optimal position, at least one light element, in the direction of whose direction marker the transmission coaster is being moved, can indicate by increasingly faster or brighter flashing when the transmission coaster is approaching the optimal position in this direction. When the optimal position is reached in this direction, this light element then changes from blinking to constant lighting. Alternatively, it can be indicated by increasingly brighter lighting when the transmission coaster is approaching the optimal position in the correct direction. A distance is then indicated by a darkening light. It can also be provided that during the movement of the transfer reducer to reach the optimal position, at least one light element, in the direction of whose direction marker the movement takes place, when the optimal position is reached in this direction from constant light to blinking with the last set brightness is ignored. This flashing can be of a limited duration, for example a few seconds as described above.

In an embodiment of the invention, it is possible that several similar or structurally identical or even identical transfer coasters are placed or positioned next to one another on the cover. This is preferably done in each case with the at least one resonant circuit coil in each transmission reducer above a single or several primary induction coils under the cover. The individual transmission coasters can touch each other. As an extension, it is even possible for the transmission coasters to be coupled to one another electrically or in terms of control technology, for example wirelessly via radio. They can also be mechanically connected or coupled so that they form a firmly connected surface. An inductively heatable cooking vessel with a size between 70% and 130% of the total area of the transfer coasters can then be placed on the several transfer coasters in order to be inductively heated by them.

It can be provided that lighting elements in the transmission reducer are supplied with power from the resonant circuit therein. This can take place via interconnected power converters or via a dedicated induction coil with a luminous element resonant circuit, which is known per se to the person skilled in the art, see for example FIG EP 1317164 A2 . Then no connection needs to be provided for this. You can also use a controller and / or sensors in the transmission reducer are supplied with power. This is because a reducer control can advantageously be arranged in the transfer reducer, in particular with a controller, which can also obtain its power from the resonant circuit. This control can also be designed to determine the optimal position, for which purpose it can, for example, evaluate the current and / or voltage in the resonant circuit or in the resonant circuit coil.

Another possibility is the use of the so-called Qi standard, which also describes inductive energy transmission and thus enables the aforementioned electrical functional units in the transmission reducer to be supplied with power. The energy can come from the primary induction coil or from the resonant circuit coil.

Advantageously, however, at least one magnetic or inductive sensor is arranged in the transmission reducer, which is designed to detect a position relative to a magnet in the inductive cooking appliance or to the primary induction coil, so it can also help in determining the optimal position. There are preferably at least two such sensors, particularly preferably four sensors.

Alternatively, at least one magnetic or inductive sensor can be arranged in the inductive cooking appliance itself, which sensor is designed to detect a position relative to a magnet in the transmission reducer or to the oscillating circuit coil therein. Here, too, there can preferably be at least two magnetic or inductive sensors, particularly preferably four sensors.

In a further embodiment, at least one temperature sensor can be arranged in the transfer reducer, preferably in the upper area of the transfer reducer. It can rest on the outside of an underside of a top layer or cover so that it can detect the temperature of the upper outside or top side, for example also of the bottom of a pot that has been set up. Such a temperature sensor is advantageously connected to an aforementioned coaster control, which can evaluate its information and, if necessary, utilize or convert it.

In a further development of the invention, communication can take place between the transfer reducer or a reducer control in the transfer reducer, on the one hand, and the primary induction coil or the cooking appliance control, on the other hand. As a result, the determination of the position of the transmission reducer can be improved, advantageously for Determination of the optimal position of the transmission reducer above the primary induction coil.

Such communication between the transmission reducer and devices or functional units arranged outside it, in particular the primary induction coil or the cooking device control, can take place by means of RFID or by radio. A radio connection can be selected from the group WLAN, Bluetooth, BLE or ZigBee. Another possibility is inductive communication or transmission, in particular with the Qi standard as defined by the Wireless Power Consortium.

The transmission coaster for an inductive cooking appliance for performing the above-described method itself can have a resonant circuit with at least one resonant circuit coil and at least one resonant circuit capacitor for transmitting inductive power from the primary induction coil via the resonant circuit into the cooking vessel placed on the transmission coaster. This transmission of inductive power can also take place quite generally in accordance with the aforementioned Qi standard.

On its upper side, the transmission coaster is advantageously made of material with an increased temperature resistance, advantageously higher than that which the cover of the inductive cooking appliance should have. The increased temperature resistance can be at least 100.degree. C., preferably at least 150.degree. C. and in particular at least 250.degree. Glass, glass ceramic or hard glass can advantageously be used as the material. The transmission reducer is advantageously designed as an independent structural unit that can be handled independently. So he is not by means of a cable or the like. connected to the inductive cooking device. So it can be easily put away when it is not needed.

In an advantageous embodiment of the invention, a layer of thermally insulating material is provided under the heat-resistant layer on the top. This can be formed over the entire area or at least largely over the entire area. This is intended to avoid excessive heating within the transfer reducer.

The resonant circuit can be integrated into the transmission reducer, preferably with a resonant circuit coil running parallel to the top and / or underside of the transmission reducer. Preferably, only a single resonant circuit coil is provided for transmitting the energy into the cooking vessel located above.

The transfer coaster can preferably be designed to be watertight or at least so that it can be closed watertight. For this purpose, for example, plugs or flaps can be provided, possibly also attached to the transfer coaster itself. The transfer coaster can also be cleaned in a dishwasher.

Ferrites or ferritic material can preferably be provided in the transfer coaster, in particular it can contain these inside. They can be used in a known manner to influence, in particular bundling or steering, the magnetic field from the primary induction coil and / or from the resonant circuit coil. This should also be able to reduce stray fields.

In an embodiment of the invention, a cooling device for the transfer reducer can be provided in the transfer reducer, preferably a fan with an air inlet and air outlet. This cooling device is advantageously arranged in the transmission reducer, and it can preferably be supplied with power from the resonant circuit in the manner described above.

The inductive cooking appliance, with which the above-described method can be carried out, advantageously for use with a transfer reducing unit as described above, has at least one primary induction coil, a flat cover over the primary induction coil, a power supply for the primary induction coil and a cooking appliance control which is connected to the power supply.

The inductive cooking appliance can have its own operating device with operating elements, in particular also with a display, which can be provided under, on or on the cover. Control elements and / or displays should, however, be reduced or not take up a lot of space in order to save space and because, depending on the design of the cover, they cannot necessarily be easily arranged. However, they can also be designed independently of the cover itself, for example arranged with a radio link outside the inductive cooking appliance.

The inductive cooking appliance advantageously has a cooking appliance control and communication means for external communication, in particular for communication with a mobile terminal, for example a tablet computer or a smartphone. Operating elements and / or display elements of the mobile terminal can also advantageously be used , whereby a very good double benefit is possible. The control or a control method can run as a so-called app on the mobile device, for example.

These and other features emerge from the claims and also from the description and the drawings, the individual features being implemented individually or in combination in the form of subcombinations in one embodiment of the invention and in other areas and being advantageous and protectable per se Can represent designs for which protection is claimed here. The subdivision of the application into individual sections and subheadings does not limit the general validity of the statements made under these.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

eine seitliche Schnittdarstellung durch ein erfindungsgemäßes induktives Kochgerät mit einem erfindungsgemäßen Übertragungsuntersetzer darauf,

Fig. 2

ein vereinfachtes schematisches Schaltbild zur Darstellung der Energieübertragung,

Fig. 3

eine Ansicht von oben auf das induktive Kochgerät mit Übertragungsuntersetzer aus Fig. 1 samt zu beheizendem Topf in getrennter Darstellung,

Fig. 4

eine Darstellung, bei der ausgehend von Fig. 3 der Übertragungsuntersetzer samt Topf auf eine Abdeckung des induktiven Kochgeräts aufgestellt worden ist mit zwei aktivierten Positionsleuchten,

Fig. 5

den Zustand ausgehend von Fig. 4, wenn der Übertragungsuntersetzer korrekt auf die Abdeckung des induktiven Kochgeräts platziert ist und

Fig. 6

eine Abwandlung der Erfindung, bei der anders als in Fig. 4 die Anzeige mit den Positionsleuchten an einem Smartphone vorgesehen ist.

Further advantages and aspects of the invention emerge from the claims and from the following description of preferred exemplary embodiments of the invention, which are explained below with reference to the figures. Show:

Fig. 1

a lateral sectional view through an inventive inductive cooking device with a transmission coaster according to the invention thereon,

Fig. 2

a simplified schematic circuit diagram to show the energy transfer,

Fig. 3

a top view of the inductive cooking device with transmission coaster Fig. 1 including the pot to be heated in a separate illustration,

Fig. 4

a representation in which, starting from Fig. 3 the transfer coaster including the pot has been placed on a cover of the inductive cooking device with two activated position lights,

Fig. 5

the state based on Fig. 4 when the transfer coaster is correctly placed on the cover of the inductive cooking appliance and

Fig. 6

a modification of the invention in which other than in Fig. 4 the display with the position lights is provided on a smartphone.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the Fig. 1 an inventive inductive cooking device 11 is shown, which consists of a cover 12 with a top 13 and a bottom 14. The cover 12 is, unlike conventional induction hobs, not made of glass ceramic or hard glass, but can be any and for induction fields be permeable plate, for example made of stone or wood, possibly at least partially provided with textile. The Upper side 13 advantageously has no marking or the like. at least not with regard to a function for the inductive cooking appliance 11.

A primary induction coil L2 is placed on the underside 14, in particular pressed or glued on. The primary induction coil L2 can be circular or approximately square or rectangular or square. It has several turns lying in one plane, and this can be varied. Furthermore, a primary capacitor C2 is provided which, together with the primary induction coil L2, forms the resonant circuit described above. Finally, ferrites 19 can also be provided, for example surrounding the primary induction coil L2 and / or also arranged therein. However, this corresponds to a known structure and does not need to be explained further. The primary induction coil L2 is connected to a corresponding power control, as is known from the prior art, and to a cooking device control. A plurality of further primary induction coils L2 can be provided on the underside 14 of the cover 12 of the inductive cooking appliance, either very close to one another in order to form a continuous surface, or at a distance.

A transfer coaster according to the invention is set up on the upper side 13 of the cover 12 and is essentially flat and can be, for example, 2 cm to 5 cm high. The transfer reducer 21 has a housing 22 so that it is advantageously designed as an integrated structural unit. A resonant circuit coil L3 together with an associated resonant circuit capacitor C3 is located in the housing 22, advantageously on the underside. These form the resonant circuit described above for transmitting inductive power from the primary induction coil L2 below it into a pot 36 above it.

Position sensors 30a-d surround the resonant circuit coil L3, the distribution of which is also derived from the Fig. 3 can be seen. These position sensors 30a-d can be magnetic or Hall sensors and serve, for example, to determine their position relative to the primary induction coil L2. This is from the Figures 3 and 4 to see. More or fewer position sensors could also be provided, possibly also within the resonant circuit coil L3 or in its essentially free central area.

Furthermore, a temperature sensor 29 is provided in the transfer reducer 21, which, surrounded by insulating material 32, rests or is pressed against the underside of a cover plate 34. This temperature sensor 29 corresponds to a temperature sensor on an induction heating coil in an induction hob, which is placed on the underside of a hob plate. In this way, a temperature of the cover plate 34 can be detected, in particular for its protection, possibly also for a hot indicator, as is known from cooktops, to an operator to warn against touching with the hand. Furthermore, the temperature sensor can possibly also be used to query or record information from a pot 36 that has been set up with regard to its temperature.

A controller 27 is also arranged in the transmission reducer 21 as the aforementioned reducer control. This can draw its energy from the resonant circuit in the transfer reducer 21, for example through its own induction coil or through a direct connection. The controller 27 can take over the aforementioned functions, in particular it can evaluate the position sensors 30a-d and possibly also control the position lights 25a-d. The controller 27 can also have a radio module in order to communicate with a controller (not shown) of the inductive cooking appliance 11 and / or an external device, for example a tablet computer or smartphone as an operating device.

In order to cool the functional components of the transfer reducer 21 in the housing 22, in particular the controller 27, a fan 31 is provided on the right outer edge. The fan 31 can also draw its energy from the resonant circuit in the transmission reducer 21 in a manner that is basically similar to that of the controller 27. The fan 31 advantageously has ventilation slots to the outside. These are particularly advantageously closable by means of built-in flaps or by means of an external stopper or the like. As a result, the transfer coaster 21 can be cleaned very well and thoroughly, for example in a dishwasher, if it is adequately sealed.

The insulating material 32 can for example be vermiculite or a fiber material or mineral fiber material. It protects the underlying functional units, in particular the controller 27 and the position sensors 30a-d, possibly also the position lights 25a-d, from excessively high temperature, which a strongly heated pot 36 can emit or radiate downwards. The cover plate 34 as a cover for the transmission coaster 21 can consist of any material that is mechanically stable, temperature-resistant and permeable to an inductive alternating field. It can advantageously be a material such as that used for induction hobs, i.e. glass ceramic or hard glass with a thickness of 1 mm to 5 mm.

In the Fig. 2 is a schematic representation of the interconnection or coupling of the resonant circuits. On the far left, the inductive cooking appliance 11 is shown with the primary induction coil L2 and the primary capacitor C2. Resistor R2 is part of the primary resonant circuit. The resistor RS is part of the power control VS for the primary resonant circuit or for the primary induction coil L2.

The primary induction coil L2 and the resonant circuit coil L3 of the transmission reducer 21 are connected by means of a magnetic coupling M23, so that the inductive energy is transmitted. The resonant circuit capacitor C3 is then also provided in the transmission reducer 21 together with a resistor R3, which represents the losses in the transmission reducer 21, in particular the copper resistance of the resonant circuit coil L3 and the internal loss resistance or series equivalent resistance of the resonant circuit capacitor C3. This resonant circuit should be as loss-free as possible, above all in order to reduce internal heating of the transfer reducer 21 as much as possible or to avoid it entirely.

The resonant circuit coil L3 is coupled to the bottom of the pot 36 by means of a magnetic coupling M34, represented here by L4 together with the magnetic parameters of this pot bottom. The resistors R4 and RL represent the losses in the pot base, in particular the eddy current losses, namely both the magnetic and the ohmic losses. They actually heat the bottom of the pot. The capacitance C4 is transmitted, so to speak, through the magnetic coupling M34 as part of the resonant circuit capacitor C3. The primary induction coil L2 can thus inductively heat the bottom of the pot 36 via the two magnetic couplings M23 and M34, specifically via the known eddy current losses in the pot 36.

In the Fig. 3 is shown in plan view of an inductive cooking device 11 with a cover 12 including top 13. There is a dashed rectangle corresponding to the dimensions of the transmission coaster 21 shown above right including a plus sign, which should only be present in the drawing for better understanding and not are actually present on the top 13. The transfer reducer 21 is shown here with a circle symbol in the left-hand area, which must be brought into overlap with the aforementioned plus symbol, but is also not actually present.

The four position sensors 30a-d on the transmission reducer 21 can be clearly seen, with the aid of which it can be recognized whether the transmission reducer 21 is already positioned in the intended position on the upper side 13 shown in broken lines. As from the Fig. 1 As can be seen, the position sensors 30a-d are located somewhat outside or radially outside of the primary induction coil L2.

Furthermore, four position lights 25a-d are shown, each on the outer edge. They have the shape of an arrow pointing outwards and can be controlled to light up as was explained at the outset, that is, as brightly or as flashing as desired.

In the Fig. 4 shows how the transfer coaster 21 has been placed on the top 13, but too far to the right and too far forward. A pot 36 that may already have been placed on the transfer coaster 21 is shown in dotted lines, but this does not necessarily have to be the case.

In the manner described at the outset, the position sensors 30a-d can detect how they are arranged relative to the primary induction coil L2, or alternatively to the ferrite 19 or to another magnet, possibly also a permanent magnet, under the cover 12. For example the primary induction coil L2 can also be briefly activated, and then the position can be determined. In the Fig. 4 it is shown that it has been noted here that the transfer reducer 21 is positioned too far to the front and too far to the right, that is to say it is not in the optimal position. The deviation of the current position from the optimal position is about 5 cm to the front and 3 cm to the right. In each case, it lies above a limit distance mentioned at the beginning, which here can be 1 cm or 2 cm, for example. The transfer reducer 21 must therefore be shifted to the left and to the rear. Therefore, the corresponding position lights 25a and 25b, represented by the two concentric circles, light up. They can light up at all, light up brighter than the other position lights 25c and 25d, or light up flashing. In any case, an operator should be able to clearly and clearly recognize from their lighted state that the transfer reducer 21 must be moved in the direction they represent and in the direction in which they are arranged relative to the transfer reducer 21. Then, if necessary, the special arrow shape can be dispensed with. A deviation in the Fig. 5 The optimal position shown from a few mm up to the mentioned 1 cm or 2 cm can be tolerated. In particular, this can also possibly compensate for the fact that the position cannot be recorded with millimeter accuracy.

The operator thus recognizes that he has to move the transfer reducer 21 to the left and to the rear. If this is done, the in Fig. 5 presented situation. The transfer reducer 21 is in the desired optimal position. Due to the desired overlap, the previously in Fig. 4 The dashed lines shown for the position of the transfer reducer 21 can no longer be seen. The plus sign is now also in the circle sign to show that the optimum position has been precisely reached. Furthermore, the position lights 25a-d are then deactivated again after they have indicated that the correct position has been reached in one of the above-described ways, for example by briefly intense flashing followed by all position lights going out. At this point at the latest, the pot 36 can be set up on the transfer coaster 21 and inductively heated by means of the primary induction coil L2 and the resonant circuit in the transfer coaster 21.

For the design according to Figs. 3 to 5 and in order to carry out the method shown there, it is generally regarded as necessary for the controller 27 to be present in the transmission translator 21. Finally, it must also control the position lights 25a-d. This could also be done by means of an external control or position detection including the necessary sensors. Then, however, at least a rudimentary control is still required in the transmission translator 21, including a radio module or the like. for communication. If these position lights are not to be arranged on the transmission coaster, there is a possible configuration of the Fig. 6 . There, an inductive cooking appliance 11 of identical design with cover 12 and top side 13 has an optimal position for the transmission coaster 121, shown by dashed lines. The Fig. 6 thus roughly corresponds to the Fig. 4 . In turn, four position sensors 130a-d are contained or arranged in the transmission reducer 121. There are just no position lights included.

Position lights 130a-d are provided here on an external device in the form of a smartphone 140 with a display 141, and in fact they are indicated by this display 141. On the display 141, an operator can see that the transmission reducer 121 is not in the optimal position and also deviates from it by more than a limit distance, so that it has to be shifted backwards and to the left because, for example, the corresponding position lights 130a and 130b light up brighter than the others or flash, as explained at the beginning. For this purpose, a controller can either send the corresponding position information to the smartphone 141 in the transmission reducer 121 or in the inductive cooking appliance 11 by radio. If the position sensors 130a-d have registered that the transmission reducer 121 is then correctly positioned after it has been moved, so that the plus sign would again lie within the circle sign, this information is sent to the smartphone 140. Corresponding information can then be displayed on the display 141, possibly also supported by text information such as "optimum position reached". As an extension, in addition to the direction, the display 141 can also show the distance by which the transmission reducer 121 must be shifted in a certain direction. This can be done as "Please move 2 cm backwards", that is with text, or only with the direction symbol and the distance to be moved "2 cm". For this, however, it must be possible not only to be able to detect the reaching of the optimum position in one direction, but also the distance by which the transmission reducer 121 is removed therefrom before the movement.

If a combination of several transmission coasters described at the beginning has to be placed together in order to heat a single cooking vessel placed on it, the position lights of all transmission coasters located on the outer edge can be used are used together, and not all position lights of all transmission coasters. In the event that a cooking vessel has already been put on, it may no longer be possible to recognize all of them.

Another possibility for the arrangement of the transmission sensors could not be under the cover plate 34 of the transmission coaster 21, but on the side edge, possibly slightly protruding or protruding. The position lights can then also be recognized when a pot has been set up that is roughly the size of the transfer coaster itself.

On the cover plate 34 in turn identifications or markings or the like. be provided, which enable a central or optimal placement of the pot on the transfer coaster 21. Finally, this surface is only intended for cooking or heating, so that, unlike on the cover 12 including the top 13 itself, a marking does not interfere.

Claims (14)

1. Method for inductively heating an inductively heatable cooking vessel (36) by means of at least one induction coil (L2) of an induction cooking appliance (11), the induction cooking appliance (11) comprising:

   - at least one primary induction coil (L2),

   - a cover (12) over the primary induction coil (L2),

   - a power supply (VS) for the primary induction coil (L2),

   - a cooking appliance control connected to the power supply (VS),

   wherein a display (25a-d, 130a-d) for an operator is provided, in order to show an operator whether or not a transmission coaster (21) is positioned in an optimum position above the primary induction coil (L2),
   characterized by
   at least one transmission coaster (21, 121) which is freely movable independently of the cooking appliance (11), in order to place it onto any position on the cover (12) above the primary induction coil (L2), wherein the transmission coaster has at least one oscillating circuit including at least one oscillating circuit coil (L3) and at least one oscillating circuit capacitor (C3) for transmission of inductive power from the primary induction coil (L2) via the oscillating circuit into the cooking vessel (36) placed on the transmission coaster (21, 121), wherein the following steps are provided:

   - detecting a position of the transmission coaster (21, 121) relative to the primary induction coil (L2),

   - in case of a deviation of the position by more than a limit distance from a predefined optimum position, giving information to the operator on the display (25a-d, 130a-d) in which direction the transmission coaster (21) is to be moved, in order to obtain the optimum position.
2. Method according to claim 1, characterized in that the optimum position and the limit distance are fixedly predefined.
3. Method according to claim 1 or 2, characterized in that the limit distance is at least 5 % of the maximum diameter of the transmission coaster (21, 121), preferably at least 5 % to a maximum of 100 % of the maximum diameter of the transmission coaster.
4. Method according to any of the preceding claims, characterized in that the display (25a-d) is integrated in the transmission coaster (21), in particular is an illuminated display and/or includes luminous elements.
5. Method according to claim 4, characterized in that the illuminated display includes luminous elements (25a-d) which preferably are disposed on different outer regions or outer sides of the transmission coaster (21) and mutually spaced, wherein in particular in each case four luminous elements are disposed on opposite sides of the transmission coaster, wherein by activating one luminous element (25a-d) an operator is given the information that the transmission coaster (21) has to be moved in the direction from its center point towards this luminous element (25a-d), in order to reach the optimum position, wherein preferably the reaching of the optimum position is shown by flashing of one or more luminous elements, in particular of all of the luminous elements.
6. Method according to claim 5, characterized in that during moving of the transmission coaster (21) to reach the optimum position at least one luminous element (25a-d), in the direction of which the transmission coaster is moved, shows by increasingly faster flashing when the transmission coaster approaches the optimum position in this direction, wherein preferably upon reaching the optimum position in this direction this luminous element changes from flashing to a constant glowing.
7. Method according to claim 5, characterized in that during moving of the transmission coaster (21) to reach the optimum position at least one luminous element (25a-d), in the direction of which the transmission coaster is moved, shows by increasingly brighter flashing when the transmission coaster (21) approaches the optimum position in this direction, wherein preferably upon reaching the optimum position in this direction this luminous element (25a-d) changes from flashing to a constant glowing.
8. Method according to claim 5, characterized in that during moving of the transmission coaster (21) to reach the optimum position at least one luminous element (25a-d), in the direction of which the transmission coaster is moved, shows by increasingly brighter glowing when the transmission coaster approaches the optimum position in this direction, wherein preferably upon reaching the optimum position in this direction this luminous element changes from constant glowing to flashing with the last set brightness.
9. Method according to any of claims 1 to 3, characterized in that the display (141) is disposed on a separate external device which is disposed apart from the induction cooking appliance (11) and the transmission coaster (121), in particular on a mobile terminal like a mobile telephone (140), a tablet computer or a television set or a display device, wherein the display (141) includes luminous elements (130a-d) as direction markers in four different uniform directions, wherein by activating one luminous element an operator is given the information that the transmission coaster (121) has to be moved in the direction of the direction marker of this luminous element, in order to reach the optimum position, wherein preferably reaching of the optimum position is shown by flashing of one or more luminous elements (130a-d), in particular of all of the luminous elements.
10. Method according to any of the preceding claims, characterized in that communication takes place between the transmission coaster (21, 121) or a coaster control (27) in the transmission coaster and the primary induction coil (L2) or the cooking appliance control, preferably for determining the optimum position of the transmission coaster (21, 121) above the primary induction coil (L2).
11. Transmission coaster for an induction cooking appliance (11) for performing the method according to any of the preceding claims, characterized in that the transmission coaster (21, 121):

    - includes an oscillating circuit including at least one oscillating circuit coil (L3) and at least one oscillating circuit capacitor (C3) for transmission of inductive power from the primary induction coil (L2) via the oscillating circuit into the cooking vessel (36) placed on the transmission coaster (21, 121),

    - on the upper side (34) thereof is composed of material having a temperature resistance of at least 100 °C,

    - includes the display (25a-d, 130a-d).
12. Transmission coaster according to claim 11, characterized in that the coaster is embodied in an independent and autonomously manageable physical unit.
13. Induction cooking appliance (11) for performing the method according to any of the claims 1 to 10, the cooking appliance comprising:

    - at least one primary induction coil (L2),

    - a flat cover (12) over the primary induction coil (L2),

    - a power supply (VS) for the primary induction coil (L2),

    - a cooking appliance control connected to the power supply (VS),

    - a transmission coaster (21, 121) according to claim 11 or 12.
14. Induction cooking appliance according to claim 13, characterized in that the appliance has a distinct operating device including operating elements, in particular also including a display, preferably below, at or on the cover (12).

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