CN115916014A - Food container - Google Patents

Abstract

A food container for food preparation equipment having a base and side walls defining a receiving space for receiving food. The food container has a susceptor for heating the receiving space and an agitator located in the receiving space. The stirrer is configured to interact with the first magnetic field of the food preparation device such that the stirrer is movable within the receiving space, the susceptor is located in the base and is configured to interact with the second magnetic field of the food preparation device such that the receiving space is heated.

Description

food container

technical field

The present invention relates to a food container, and a food preparation system comprising such a food container.

Background technique

In the area of food preparation, traditional methods of cooking on a stovetop, where the stovetop is gas or electric powered, can be energy inefficient. Hobs that heat pans by magnetic induction, so-called induction hobs, are known to offer greater energy efficiency than gas or electric powered hobs.

Contents of the invention

According to a first aspect of the present invention there is provided a food container for use with food preparation apparatus, the food container comprising a base and side walls defining a receiving space for receiving food, a susceptor for heating the receiving space, and a receiving a stirrer in the space configured to interact with the first magnetic field of the food preparation device to enable movement of the stirrer in the receiving space, the susceptor is located in the base and configured to interact with the second magnetic field of the food preparation device , so that the receiving space is heated.

A food container according to the first aspect of the invention may primarily be beneficial in that the food container comprises a susceptor for heating the receiving space and an agitator in the receiving space, the agitator being configured to interact with the first magnetic field of the food preparation device such that The stirrer is movable within the receiving space, the susceptor is located in the base and is configured to interact with the second magnetic field of the food preparation device such that the receiving space is heated.

In particular, providing a stirrer that is movable by interacting with a magnetic field may allow the stirrer to move automatically without the application of force by a user. This may provide an improved user experience relative to devices that require the user to continuously apply manual force to the blender when the function of the blender is desired.

Furthermore, since the food container includes the susceptor and the stirrer, eg as separate parts, an improved heating pattern can be provided compared to the case where the stirrer is also used as the susceptor. For example, where the stirrer is also used as the susceptor, heating may only be provided in the immediate vicinity of the stirrer's current location. In contrast, the use of separate susceptors and stirrers in the present invention may allow heating to be provided in an area remote from the current location of the stirrer. This can, for example, provide a more uniform heating of the receiving space.

The base may include a non-susceptor portion aligned with the stirrer. This may improve the interaction with the second magnetic field of the food preparation device compared to eg an arrangement where the susceptor portion extends substantially across the entire base.

The susceptor and non-susceptor portions may be arranged concentrically within the base. This can provide a relatively simple arrangement and also enable eg heating of the entire annular portion of the receiving space and/or movement of the stirrer around the entire annular portion of the receiving space. The base may be substantially circular. The stirrer may be configured to interact with the first magnetic field of the food preparation device such that the stirrer may rotate within the receiving space, for example around a central axis of the food container.

The non-susceptor portion may be arranged substantially centrally on the base, and the susceptor may extend annularly around the non-susceptor portion. This may be beneficial as it ensures that the agitator moves about a substantially central point of the base and that the agitator moves substantially uniformly within a predetermined portion of the receiving space. This also enables the susceptor to extend from the central area of the base to the side walls, eg making it possible to provide heating over a relatively large area of the food container.

The susceptor may be centrally arranged on the base, and the non-susceptor portion may extend annularly around the susceptor. This may be beneficial because the non-susceptor portion may have an increased radius compared to an arrangement in which the non-susceptor portion is arranged substantially in the center of the base and the susceptor extends annularly around the non-susceptor portion. The increased radius of the non-susceptor portion may allow for an increased level of torque delivered to the agitator, which may be beneficial for certain types of agitators, and may allow for the use of different types of agitators.

The food container may include a first male magnetic assembly configured to interact with a second male magnetic assembly of the food preparation device when the food container is placed on the food preparation device to inhibit the food container from for the movement of food preparation equipment. This may be beneficial as it may effectively lock the food container to the food preparation device, eg such that rotation of the food container relative to the food preparation device is inhibited. This may be particularly beneficial if, for example, the stirrer is caught by an item in the receiving space, which would otherwise cause the food container to rotate relative to the food preparation device.

Providing corresponding first and second male magnetic assemblies in the food container and food preparation equipment may also allow the food container to be guided into a predetermined orientation relative to the food preparation equipment during placement of the food container on the food preparation equipment .

The first male magnetic assembly may include an annular ring having a plurality of protrusions extending from the annular ring. This may allow multiple orientations of the food container relative to the food preparation apparatus, eg each protrusion defines a respective orientation. A greater number of protrusions may reduce the degree of relative movement between the food container and the food preparation device, which may eg prevent excessive rotation of the food container during placement on the food preparation device.

The susceptor may define a first male magnetic component. This can provide dual functionality and reduce part count and manufacturing cost compared to devices with separate susceptors and convex magnetic assemblies.

The stirrer may include a pair of poles for interacting with the first magnetic field of the food preparation device.

The blender can be removed from the food container. This may allow for easier cleaning of the food container and blender, and may allow for replacement of the blender, for example. The stirrer can comprise any of several types of stirrers, so the stirrer can be replaced to allow for increased functionality.

The stirrer may include a stirrer for stirring food received in the receiving space. This may allow automatic agitation to receive food in the receiving space, which may allow the food container to be left unattended in use, thereby enhancing the user experience. The stirrer may only require low torque and thus may be particularly useful for an arrangement in which the non-susceptor portion is disposed substantially in the center of the base and the susceptor extends annularly around the non-susceptor portion.

The blender may include blades for chopping food received in the receiving space. For example, this may allow the food container to function as a blender in addition to or instead of providing a stirring function. Blades may benefit from increased torque levels and thus may be particularly useful for arrangements where the susceptor is centrally arranged on the base and the non-susceptor portion extends annularly around the susceptor.

The receiving space may include a liquid reservoir for receiving liquid and a food receiving portion for receiving food, the stirrer may be located in the liquid reservoir, the susceptor may be configured to interact with the first magnetic field to heat the liquid in the liquid reservoir, The agitator may be configured to interact with the second magnetic field such that the agitator is movable within the liquid reservoir to transfer liquid from the liquid reservoir to the food receiving portion. This may enable the food container to be used in a splash cooking method in which food is cooked by interacting with heated liquid droplets, such as heated water droplets. Such splash cooking may be relatively energy efficient, but generally may require a longer cooking time. Since the food container of the present invention provides automation of the heating and movement of the agitator, the food container can be left unattended in use, which facilitates cooking methods such as splash cooking.

The susceptor may comprise a plurality of continuous filaments extending along the base and up to the sidewalls. For example, extending the susceptor up the sidewall may provide improved heat distribution relative to an arrangement in which the susceptor is only located in the base. Using filaments as susceptors may reduce the required thickness of the base, which may allow enhanced interaction of the stirrer with the first magnetic field of the food preparation device, eg by bringing the stirrer closer to the food preparation device.

The food container may include insulation disposed on the base and side walls. This reduces the risk of contact with heated surfaces during use. The insulating layer may be attached to the base and side walls by any suitable mechanical connection, such as via adhesive or screw connections or the like.

According to a second aspect of the present invention there is provided a food preparation system comprising a food container according to the first aspect of the invention and a food preparation device, wherein the food preparation device comprises a magnetic field generator configured to generate first and second magnetic fields.

The food preparation device may comprise a contact surface under which the magnetic field generator is arranged.

The magnetic field generator may include a magnetic core structure, a coil wound around the magnetic core structure, and an excitation device configured to excite the coil. The magnetic core structure may include a first magnetic flux path configured to interact with a susceptor of the food container to define a first magnetic flux path. The magnetic pole pair, the magnetic core structure may include a second magnetic pole pair configured to interact with the agitator of the food container to define a second magnetic flux path. Thus, the first and second magnetic flux paths may allow the first and second magnetic fields to be generated in use. The arrangement of the first and second pole pairs can be adjusted to provide optimized magnetic fields for heating and motion, respectively. For example, the distance between the poles of respective pole pairs or the relative size of the poles of a pole pair may affect the magnetic field generated in use.

The magnetic field generator may include a plurality of first magnetic pole pairs configured to interact with the susceptor of the food container to define a corresponding first magnetic flux path, and a plurality of second magnetic pole pairs configured to interact with the agitator of the food container. Acting to define a corresponding second flux path, the first and second pole pairs are arranged annularly. This can be beneficial as it enables heating around the entire annular extent of the food container and allows efficient rotational movement of the agitator.

A plurality of second pole pairs may be sequentially energized to drive motion of the stirrer.

The magnetic field generator may define a convex magnetic assembly, such as the second convex magnetic assembly discussed above. This can inhibit movement of the food container relative to the food preparation equipment, eg rotational movement.

According to a third aspect of the present invention there is provided a food container for use in food preparation equipment, the food container comprising a base and side walls extending from the base to define a receiving space for receiving food, the base comprising a susceptor portion and a A non-receptor portion with concentric arrangement of the receptor portion.

Where appropriate, preferred features of aspects of the invention may apply equally to other aspects of the invention.

Description of drawings

Figure 1 is a schematic diagram of a food preparation system according to one example;

Figure 2 is a schematic diagram of a first embodiment of a magnetic field generator for the food preparation system of Figure 1;

Fig. 3 a is the schematic diagram of the first excitation waveform of the excitation device of the magnetic field generator of Fig. 2;

Figure 3b is a schematic diagram of the electronic circuitry used to generate the excitation waveform of Figure 3a;

Fig. 3c is the schematic diagram of the second excitation waveform of the excitation device of the magnetic field generator of Fig. 2;

Figure 3d is a schematic diagram of the electronic circuitry used to generate the excitation waveform of Figure 3c;

Figure 3e is a schematic diagram of a first embodiment of an applied voltage relative to a supply voltage;

Figure 3f is a schematic diagram of a first embodiment of an applied voltage relative to a supply voltage;

Figure 4a is a schematic perspective view of a magnetic core of the magnetic field generator of Figure 2;

Figure 4b is a schematic side view of the magnetic core of Figure 4a placed under a food container;

Figure 5 is a schematic illustration of a first embodiment of a food container for the food preparation system of Figure 1;

Figure 6a is a schematic diagram of a first embodiment of the susceptor portion of the food container of Figure 5;

Figure 6b is a schematic diagram of a first embodiment of the susceptor portion of the food container of Figure 5;

Fig. 7 is the schematic diagram of the agitator of the food container of Fig. 5;

8 is a schematic diagram of a second embodiment of a magnetic field generator for the food preparation system of FIG. 1;

9 is a schematic diagram of a third embodiment of a magnetic field generator for the food preparation system of FIG. 1;

Figure 10 is a schematic diagram of the magnetic field generator of Figure 9 utilizing a first magnetic core arrangement;

Figure 11 is a schematic diagram of the magnetic field generator of Figure 9 utilizing a second magnetic core arrangement;

12 is a schematic diagram of a fourth embodiment of a magnetic field generator for the food preparation system of FIG. 1;

13 is a schematic diagram of a second embodiment of a food container for use with the food preparation system of FIG. 1;

14 is a schematic diagram of a third embodiment of a food container for use with the food preparation system of FIG. 1;

Figure 15 is a schematic diagram of the magnetic assembly of the food container of Figure 14;

16 is a schematic diagram of a fourth embodiment of a food container for the food preparation system of FIG. 1;

17 is a schematic bottom view of a fifth embodiment of a food container for the food preparation system of FIG. 1;

Figure 18 is a schematic side view of the food container of Figure 17; and

19 is a schematic diagram of a fifth embodiment of a magnetic field generator for use with the food preparation system of FIG. 1 .

Detailed ways

A food preparation system according to the invention is shown schematically in FIG. 1 , indicated generally at 10 . The food preparation system 10 includes a food preparation device 100 and a food container 200 placed on the food preparation device 100 . The food preparation apparatus 100 takes the form of an induction cooker and may be used, in use, to heat food contained in a food container 200, as will be described below.

The food preparation device 100 includes a contact surface 102 on which the food container 100 can be placed and a magnetic field generator 104 disposed below the contact surface 102 . It will be appreciated that the food preparation device 100 may include further features, such as user input, for example in the form of one or more user-actuatable buttons or the like, but these features are not shown here.

A first exemplary embodiment of the magnetic field generator 104 is shown schematically in the upper view of FIG. 2 . The magnetic field generator 104 includes six magnetic cores 106 each wound with a respective coil 108 and an excitation device 110 (shown in FIG. 1 ) for exciting the coils 108 . The excitation device 110 includes an electronic circuit 112 capable of converting the mains power supply into a form suitable for exciting the coil 108 . Examples of suitable excitation modes of the excitation device 110 and the electronic circuit 112 are described with reference to Figs. 3a-d.

As mentioned above, the food preparation device 100 takes the form of an induction cooker. Induction cooktops work by inducing eddy currents in electrical conductors by changing the applied magnetic field in the electrical conductors. In the case of a fixed electrical conductor, as in the case of an induction cooker, the applied magnetic field must be varied to induce the required eddy currents. This variation can be achieved using pulse width modulation (PWM), and adjusting the duty cycle and/or frequency of the PWM can provide variable heating control. It is also known to synthesize low frequency voltage waveforms from DC voltages. If the frequency of the PWM is high enough, it can be considered that the PWM frequency is largely independent of the synthesis of the low frequency voltage. Thus, the present invention can provide variable induction heating while maintaining a low frequency voltage that can be used to drive the agitator of the food container 200 .

In some embodiments, as will be described below, not all coils 108 need to be energized at the same time. This may result in an arrangement requiring discrete excitation patterns for different subsets of coils 108 . For example an excitation pattern wherein a first subset of coils 108 is energized for a first period of time 101 and a second subset of coils 108 is not energized during a first period of time 101 and wherein a second subset of coils 108 is energized for a second period of time 103 , while the first subset of coils 108 are not energized during the second time period 103 . This excitation pattern is shown in Figure 3a.

Fig. 3b shows the electronic circuit 112 for implementing the excitation mode of Fig. 3a. Electronic circuit 112 is implemented as an AC-AC converter. The electronic circuit 112 includes an inductor _LF and a capacitor _CF that together define a low pass filter, a first switching bridge SW1-4 for the first subset of coils 108 and a second switching bridge SW5 for the second subset of coils 108 -8. The provision of two such switching bridges SW1-8 enables independent excitation of the first and second subsets of coils 108 . Thermal fluctuations and speed fluctuations are acceptable to the food preparation system 10 of the present invention, so the electronic circuit 112 may not require large energy storage components, such as DC link capacitors.

In other embodiments, each coil 108 may be energized simultaneously with every other coil 108 . Therefore, only one excitation pattern is required, which is shown in Figure 3c. As can be seen in Figure 3c, the voltage applied to the coil 108 alternates between positive and negative, where the voltage is applied, a positive voltage is applied during the negative period of the AC power cycle, and a positive voltage is applied during the positive cycle of the AC power cycle. negative voltage.

Fig. 3d shows the electronic circuit 112 for implementing the excitation mode of Fig. 3c. Electronic circuit 112 is implemented as an AC-AC converter. The electronic circuit 112 includes an inductor _LF and a capacitor _CF that together define a low-pass filter, and a single bridge of switches SW1 - 4 for the plurality of coils 108 .

The electronic circuit 112 of Figure 3d may be simpler than the electronic circuit 112 of Figure 3b since fewer switches are required. In some examples, the switches may be bidirectional gallium nitride (BiGaN) switches capable of operating at relatively high switching frequencies, eg, greater than 100 kHz. Reducing the number of BiGaN switches required reduces cost.

It should be appreciated that in some embodiments it may be beneficial to provide separate converters for each coil 108 . In such an embodiment, the PWM applied to each converter can be phase shifted, which is a common method used in parallel converter arrangements, to increase the effective operating frequency seen by the input low-pass filter, allowing for L _F and _CF for more compact and cost-effective component selection.

The excitation patterns of Figures 3a and 3c depict an embodiment as shown in Figure 3e, where the applied voltage is only applied unidirectionally for each excitation cycle. In other embodiments, as shown in Fig. 3f, in a single excitation cycle, the applied voltage can be in two directions, positive and negative. This can provide the desired net positive voltage while maximizing the high frequency content, which facilitates the induction of eddy currents in the susceptor material. However, in the embodiment of Figure 3f, a mains input filter may be required to provide a general low-pass characteristic, in contrast to the embodiments of Figures 3a and 3c.

Referring back to FIG. 2 , six magnetic cores 106 are arranged in a circular array. Each magnetic core 106 includes a core back 114 , and a first arm 118 and a second arm 120 extending from the core back 114 and having respective free ends 122 . A coil 108 is wound on each core back 114 . In FIG. 2, the first arm 118 and the second arm 120 extend inwardly towards the center of the annular array of magnetic cores 106, but it should be understood that in alternative embodiments the first arm 118 and the second arm 120 may extend from the back of the core. 114 extends outwardly. The first arm 118 and the second arm 120 are angled toward each other such that the distance (eg, slot width) between the arms 118 , 120 decreases from the core back 114 to the free end 122 .

The shape of the magnetic core 106 can be seen more clearly in FIG. 4 , where a single magnetic core 106 is shown in isolation. Each magnetic core 106 has a first pair of poles 126 on the core back 114 and a second pair of poles 130 on the first arm 118 and the second arm 120 such that one pole 130 of the second pair is on each on the arms 118,120.

Each pole 126 of the first pair of poles has substantially the same shape and has a generally circular cross-sectional shape such that the poles 126 are generally cylindrical. Of course, it will be appreciated that other cross-sectional shapes may be used as appropriate. A first pair of poles 126 extends upwardly from the core back 114 such that the poles 126 extend toward the contact surface 102 . The first pair of poles 126 are spaced apart along the core back 114 such that the poles 126 are located at opposite ends of the core back 114 . The first pair of poles 126 together define a magnetic permeance for directing the magnetic flux generated when the coil 108 is energized in use, such that the poles 126 form part of a first magnetic circuit.

Each pole 130 of the second pair of poles has substantially the same shape and has a generally circular cross-sectional shape such that the poles 130 are generally cylindrical. The diameter of the second pair of poles 130 is smaller than the diameter of the first pair of poles 126 such that the second pair of poles 130 is smaller than the first pair of poles 126 . A second pair of poles 130 extends upwardly from respective free ends 122 of the first arm 118 and the second arm 120 such that the poles 130 extend towards the contact surface 102 . As shown in Figures 4 and 4b, the length of the second pair of poles 130 is less than the length of the first pair of poles 126, although it will be appreciated that the relative lengths may be adjusted depending on the desired application. The second pair of poles 130 together define a magnetic permeance for guiding the magnetic flux generated when the coil 108 is energized in use, such that the poles 130 form part of a second magnetic circuit.

As mentioned above, the first arm 118 and the second arm 120 are angled toward each other, as best seen in FIG. 2 , such that the distance between the arms 118 , 120 decreases from the core back 114 to the free end 122 . Since the first pair of poles 126 are located at opposite ends of the core back 114 and the second pair of poles 130 is located at the free ends 122 of the first arm 118 and the second arm 120, the distance between the first pair of poles 126, that is, the first pair The air gap between the magnetic poles 126 is greater than the distance between the second pair of magnetic poles 130 , that is, greater than the air gap between the second pair of magnetic poles 130 .

As shown in FIG. 4 b , the first pair of poles 126 is longer than the second pair of poles 130 . This means that the air gap between the first pair of poles 126 and the relevant portion of the food container 200 is smaller than the corresponding air gap between the second pair of poles 130 and the relevant portion of the food container 200 . Thus, when the coil 108 is energized, first and second magnetic flux circuits having different characteristics are created in the first pair of poles 126 and the relevant portion of the food container 200 and in the second pair of magnetic poles 130 and the relevant portion of the food container 200, i.e. First and second magnetic fields, which allow different functions of different parts of the food container 200, as will be described below. By changing the relative ratio of the air gap between the first pair of magnetic poles 126 and the relevant portion of the food container 200 and the corresponding air gap between the second pair of magnetic poles 130 and the relevant portion of the food container 200, the first and second magnetic poles can be adjusted. The relative flux ratio between flux circuits.

The air gap between the first pair of poles 126 and the relevant portion of the food container 200, and the air gap between the second pair of magnetic poles 130 and the relevant portion of the food container 200, is selected to be smaller than the air gap between the pole pairs such that As much magnetic flux as possible is associated with the relevant portion of the food container 200 in use. By increasing the air gap between the pole pairs, flux leakage can be reduced, allowing more flux to couple to the relevant portion of the food container 200 in use.

It should also be understood that given the form of the plurality of magnetic cores 106 , a plurality of magnetic poles are defined around the annular array, and that the plurality of magnetic cores 106 define a first convex magnetic assembly in the food preparation apparatus 100 .

A first embodiment of a food container 200 for a food preparation device 100 is schematically shown in cross-section in FIG. 5 .

The food container 200 includes an outer pot 202 , an inner pot 204 , a lid 206 , a handle 208 and a stirrer 210 . Here, the food container 200 generally takes the form of a saucepan.

The outer pot 202 includes a generally circular base 212 and side walls 214 extending upwardly from the periphery of the base 212 to define a hollow interior for receiving the inner pot 204 . The outer pot 202 is formed of a heat insulating material, such as a suitable plastic material, so that the outer pot 202 is safe to the touch in use, and also reduces heat loss, thereby improving thermal efficiency. A pickup power coil 216 and a temperature sensor 218 are attached to the side wall 214 in the region of the connection of the handle 208 to the side wall 214 . In some embodiments, the temperature sensor 218 is kept in contact with the inner pot 204 by a loading mechanism to ensure good thermal contact in use. The handle 208 is attached to the side wall 214, is substantially hollow, and houses one or more electronic components 220, such as a transceiver or the like, configured to communicate the temperature within the food container 200 to a user. Pickup power coil 216 is capable of interacting with the magnetic field generated by magnetic field generator 104 in use for powering temperature sensor 218 and/or other electronic components housed within handle 208 . Electronic components, such as pick-up power coil 216 within handle 208 , temperature sensor 218 and electronic components 220 are attached to outer pot 202 since outer pot 202 typically does not come into contact with food in use and may not require much cleaning.

The inner pot 204 includes a generally circular base 222 and side walls 224 extending upwardly from the base 222 to define a receiving space 226 for receiving food. The diameter of the base 222 of the inner pot 204 is smaller than the diameter of the base 212 of the outer pot 202 so that the inner pot 204 can be received inside the outer pot 202 . In FIG. 5 , the inner pot 204 is shown partially received within the outer pot, with the base 222 of the inner pot 204 sitting on top of the base 212 of the outer pot 202 in the fully inserted state. In some embodiments, an interlock mechanism (not shown) is provided to lock the inner pot 204 to the outer pot 202, thereby inhibiting relative movement between the inner pot 204 and the outer pot 202 in use, and allowing Food can be poured out. A lid 206 may be attached to the upper periphery of the inner pot 204 to seal the receiving space 226 . In some embodiments, the lid 206 may be releasably locked to the inner pot 204, eg, with a small gap between the lid 206 and the inner pot 204 to allow for pressure equalization.

The base 222 of the inner pot 204 includes a susceptor portion 228 and a non-susceptor portion 230 . Susceptor portion 228 includes a conductive material, such as a ferrous material, for interacting with the magnetic field generated by magnetic field generator 104 to induce eddy currents to flow within susceptor portion 228 , resulting in heating of receiving space 226 . Therefore, the food container 200 can be heated by so-called induction heating.

In some embodiments, the susceptor portion 228 includes an annular ring 232 having a plurality of protrusions 234 on the periphery of the annular ring 232, as schematically shown in Figure 6a. Thus, the susceptor portion defines a second male magnetic component for interacting with the first male magnetic component in the food preparation device 100 .

In use, when the food container 200 is placed on the food preparation apparatus 100, the first convex magnetic assembly defined by the plurality of magnetic cores 106 interacts with the second convex magnetic assembly defined by the susceptor portion 228 such that the food product Movement (ie, rotation) of the container 200 relative to the food preparation apparatus 100 is inhibited. This may be beneficial as it may effectively lock the food container 200 to the food preparation apparatus 100, eg such that rotation of the food container 200 relative to the food preparation apparatus 100 is inhibited. This may be particularly beneficial if, for example, the blender 210 is caught by items within the food container 200 , which would otherwise cause the food container 200 to rotate relative to the food preparation device 210 . This may allow food container 200 to be left unattended while in use.

Providing corresponding convex magnetic assemblies in the food container 200 and the food preparation device 100 may also allow the food container 200 to be guided to a predetermined position relative to the food preparation device 100 during placement of the food container 200 on the food preparation device 100 . position.

In the embodiment of FIG. 6 a , the number of protrusions 234 corresponds to the number of poles of the second pair of poles 130 of the magnetic core 106 of the magnetic field generator 104 . In an alternative embodiment, as shown in FIG. 6 b , the number of protrusions 234 is twice the number of the second pair of poles 130 of the magnetic core 106 of the magnetic field generator 104 . This may reduce the degree to which the food container 200 may rotate relative to the food preparation apparatus 100 before being locked in place, such as during placement of the food container 200 on the contact surface 102, but may result in distortion of the associated pole face of the susceptor portion 228. The area is reduced, which can reduce bulge. It should be appreciated that the number of poles of the susceptor portion 228 may be selected to reduce the allowable range of rotation during placement of the food container 200 while maintaining a good level of protrusion to lock the food container 200 in place and allow the protrusion Matching the number of poles 234 to the number of poles of the second pair of poles 130 of the magnetic core 106 can provide the proper balance.

The non-susceptor portion 230 is formed of an electrically insulating material that allows the magnetic field generated by the magnetic field generator 104 to pass therethrough. In the embodiment of FIG. 5, the non-susceptor portion 230 is located substantially in the center of the base 222 and is generally circular. The susceptor portion 228 extends annularly around the non-susceptor portion 230 and extends substantially to the side wall 224 .

Agitator 210 is shown schematically in FIG. 7 and includes a central body 236 and a plurality of arms 238 extending outwardly from central body 236 . In this embodiment, the stirrer 210 is a stirrer and each arm 238 has a stirrer blade 240 extending substantially perpendicular to one end of the arm 238 to either side of the arm 238 . Each stirrer blade 240 is provided with a bar magnet 242 having a north pole and a south pole. The bar magnet 242 interacts with the magnetic field generated by the magnetic field generator 104, as will be described below. Although a bar magnet 242 is shown here, it should be understood that in some embodiments, the stirrer may simply comprise a ferrous structure. It should also be understood that, in practice, the structure of the agitator 210 described above is enclosed within a housing which, in use, rotates with the structure.

The stirrer 210 has a diameter smaller than or equal to the diameter of the non-susceptor portion 230 and is placed in the receiving space 226 of the inner pot 204 such that the stirrer 210 , especially the bar magnet 242 is located above the non-susceptor portion 230 . This may facilitate the interaction of the bar magnet 242 with the magnetic field of the magnetic field generator 104 . In some embodiments, inner pot 204 and agitator 210 may include respective positioning features, such as corresponding protrusions and recesses, which are used to position agitator 210 relative to inner pot 204 while also allowing agitator 210 to be positioned relative to inner pot. 204 spins.

In use, the food container 200 is placed on the food preparation apparatus 100 , for example, the first and second male magnetic assemblies interact to guide the food container 200 into position on the contact surface 102 of the food preparation apparatus 100 . The food container 200 is positioned on the contact surface 102 such that the susceptor portion 228 of the inner pot 204 covers the poles 126 of the first pair of poles of each magnetic core 106, and the non-susceptor portion 230 of the inner pot 204 and the stirrer 210 cover each magnetic core The poles 130 of the second pair of poles 106 are shown in Fig. 4b.

The coils 108 are excited by the excitation means 110 such that first and second magnetic flux circuits are created between the first pair of poles 126 and the susceptor portion 228 and between the second pair of poles 130 and the stirrer 210 of each magnetic core 106, i.e. first and second magnetic fields. Given the difference in the relative distances between the first pair of poles 126 and the susceptor portion 228 and between the second pair of poles 130 and the stirrer 210, as shown in Figure 4b, the first and second magnetic circuits have different reluctance . As described above, the magnetic fields generated at the first pair of poles 126 and the second pair of poles 130 have different characteristics due to the different reluctances of the first and second flux circuits. In this embodiment, the magnetic field generated at each first pair of magnetic poles 126 is a first changing magnetic field, that is, an alternating magnetic field, which interacts with the susceptor portion 228 so that eddy currents are generated in the susceptor portion 228, and the receiving space 226 is heated. The magnetic field generated at each second pair of poles 130 is a second changing magnetic field, ie an alternating magnetic field, which interacts with the bar magnet 242 to cause the stirrer 210 to rotate within the receiving space 226 . In this manner, agitator 210 may be used to agitate food received within receiving space 226 . The coil 108 is energized and the height and spacing of the poles 126, 130 are chosen such that less flux flows in the second magnetic field relative to the first, thereby controlling the rotational speed of the stirrer 210 to a reasonable stirring level.

In the manner described above, the food preparation system 10 may allow for heating and automatic agitation of the food container 200, with the convex magnetic assembly allowing the food preparation system to be left unattended in use. Temperature sensor 218 may monitor the temperature of the food product in receiving space 226 and communicate the temperature to a user, such as a remote user, via a transceiver within handle 208 . Additionally or alternatively, the temperature sensor 218 may communicate the temperature to the activation device 110 and in response the activation device 110 may control the activation of the coil 108 to adjust the heating rate. Since the food container 200 includes the susceptor 228 and the stirrer 210 , eg, as separate components, an improved heating pattern may be provided compared to the case where the stirrer 210 also acts as the susceptor 228 . For example, where agitator 210 also acts as susceptor 228, heating may only be provided in the immediate vicinity of agitator 210's current location. Conversely, using separate susceptor 228 and agitator 210 may allow heating to be provided in an area remote from the current location of agitator 210 . This may, for example, provide more uniform heating of the receiving space 226 .

While the agitator 210 described above has the agitating blades 240, it should be understood that other forms of agitators utilizing rotational motion may also be used in the food container 200. For example, a blender with multiple cutting blades may be used with food container 200 . Accordingly, the agitator 210 of the food container 200 may be removed and replaced within the food container 200 . For example, the agitator 210 may also be removable for cleaning. Assuming a bar magnet 242 is used, an implement having a magnet or ferrous portion at one end can be used to engage the stirrer 210 and then remove the stirrer from the food container 200 . In this way, the blender 210 can be safely removed during use since the user does not directly touch the blender 210 .

While described above as having multiple discrete magnetic cores 106, other embodiments of a magnetic field generator 400 may include a single toroidal core back 402 from which a plurality of arms 404 extend inwardly, as shown schematically in FIG. extend. In a manner similar to the embodiment of the magnetic field generator 104 of FIG. 2 , a first pair of poles 408 is located on the annular core back 402 and a second pair of poles 412 is located at the free end 414 of the arm 404 . A coil 416 is wound on a single toroidal core back 402 between a first pair of poles 406 . Such a magnetic field generator 400 may operate in a manner similar to the magnetic field generator 104 of FIG. 2 . For example, using a single toroidal core back may increase ease of alignment during manufacturing, but may result in increased magnetic losses due to flux leakage along the toroidal core back 402 .

In some embodiments, not all of the second pair of poles 130 of the magnetic field generator 104 may be required to achieve rotation of the stirrer 210 . For example, it may be the case that only every other second pair of poles 130 is required to achieve rotation of the stirrer 210 . In this case, the coils 108 corresponding to the second pair of poles 130 that do not need to be rotated may be energized differently than the coils 108 corresponding to the second pair of poles 130 that are required to be rotated, for example at a higher frequency. , so that the second pair of poles 130 not required to effect rotation of the stirrer 210 instead define a magnetic flux circuit and generate a changing magnetic field for interacting with the susceptor of the food container 200 to heat the receiving space 226 . It should be understood that in such an embodiment, the shape of the susceptor portion 228 may be changed accordingly, or even the agitator 210 may include a susceptor, such as an additional susceptor. In such an embodiment, the coils 108 in a single annular array may be considered to provide both heating and rotation, with the coils for rotation intermediate the coils for heating.

FIG. 9 schematically shows another embodiment of a magnetic field generator 500 . In this embodiment, the magnetic field generator comprises a plurality of coils 502 arranged in a circular array, the coils 502 in the circular array being at a substantially common radial distance from the center point of the circular array. The coils 502 include a first subset of coils 506 and a second subset of coils 508 . Each coil 502 of the second subset of coils 508 is located midway between adjacent coils of the first subset of coils 506 in the circular array.

The first subset of coils 506 are configured, in use, to generate a respective first magnetic field. In particular, the excitation means of the magnetic field generator 500 are configured to deliver varying voltages across the first subset of coils 506, thereby generating a corresponding first magnetic field. The excitation frequency is selected such that the corresponding first magnetic field can interact with the susceptor of the food container to heat the food container.

The second subset of coils 508 is configured, in use, to generate a corresponding second magnetic field. In particular, the excitation means of the magnetic field generator 500 are configured to deliver varying voltages across the second subset of coils 508 to generate a corresponding second magnetic field. The excitation frequency is chosen such that the respective second magnetic field differs from the first magnetic field and enables the respective second magnetic field to interact with the stirrer of the food container.

Since the coils 502 of the second subset of coils 508 are located in the middle of adjacent coils 502 of the first subset of coils 506, the interaction of the food preparation equipment with the susceptors and agitators of the food containers can be achieved at a common radial distance. Furthermore, such devices may be relatively compact arrangements and/or devices with fewer component parts, e.g., as compared to devices with nested annular arrays, where one array is configured to interact with the susceptor and one array is configured to interact with the stirring device interaction.

The food container 200 of FIG. 5 may be adapted to the magnetic field generator 500 of FIG. 9 when the food container 200 includes the susceptor portion 228 having a shape as shown in FIG. 6a. In particular, the food container 200 may be placed on the contact surface 102 of the food preparation apparatus 100 such that the protrusions 234 of the susceptor portion 228 are aligned with the coils 502 of the first subset of coils 506 such that the first coil 502 produced by the first subset of coils 506 A magnetic field may interact with susceptor portion 228 to cause heating of receiving space 226 of food container 200 . The plurality of coils 502 define a first male magnetic assembly for interaction with a second male magnetic assembly defined by the susceptor portion 228, as previously described.

It should be understood that some modifications of the previously described stirrer 210 may be employed for use with the magnetic field generator 500 of FIG. 9 . In particular, the length of the plurality of arms 238 can be extended such that the bar magnets 242 are located at substantially the same radial distance from the protrusions 234, or the number of poles present in the stirrer 210 can be varied such that the total number of poles of the stirrer 210 is predictable to allow rotation. In this case, when placed on the contact surface 102 of the food preparation apparatus 100, the coils 502 of the second subset of coils 508 may be positioned midway between adjacent protrusions 234 of the susceptor portion 228 of the food container 200 such that the non-susceptor portion The coils 502 of the second subset 508 of coils are covered. This may facilitate interaction between the second magnetic field generated by the second subset of coils 508 and the stirrer 210 to cause the stirrer 210 to rotate within the receiving space 226 of the food container 200 .

In some embodiments, it may not be necessary for all of the coils 502 of the second subset of coils 508 to cause rotation of the stirrer 210 at the same time. In this manner, the coils 502 of the second subset of coils 508 may be sequentially energized to drive the stirrer 210 in rotation. In such an embodiment, the coils 502 of the second subset of coils 508 may be considered to have a first excitation state in which the coils 502 generate their respective second magnetic fields, and a second excitation state in which the coils 502 generate their respective second magnetic fields, and a second excitation state in which the coils 502 generate their respective second magnetic fields. In the state, the coils 502 do not generate their respective second magnetic fields. In some embodiments, the coils 502 of the second subset of coils 508 may have a third energized state in which they interact with the susceptor portion of the food container to heat the food container. In such embodiments, it may be desirable to modify the susceptor portion and/or the stirrer compared to previous embodiments, for example by providing a stirrer that also includes susceptor material.

Although the plurality of coils 502 are only schematically shown in FIG. 9 , in practice, the plurality of coils 502 may be wound on a magnetic core for guiding magnetic flux generated in use. 10 and 11 illustrate an example embodiment utilizing a magnetic core with multiple coils 502 . In the embodiment of FIG. 10 , each of the plurality of coils is wound on a core back 510 of a separate magnetic core, each core including a pair of upwardly extending poles 512 . In the embodiment of FIG. 11 , each of the plurality of coils 502 is wound on a common toroidal core back 514 from which pairs of poles 516 extend upwardly. It should be understood that the number of coils 502 has been reduced in the embodiment of Figures 10 and 11 for ease of illustration, and that the number of coils and poles may be selected according to, for example, the susceptor portion of a food container.

Another embodiment of a suitable magnetic field generator 600 is shown in FIG. 12 . The magnetic field generator 600 of FIG. 12 utilizes the same plurality of magnetic cores 106 as the magnetic field generator 104 of FIG. 602 and the second coil 604. The first coil 602 is wound on the pole 126 of the first pole pair, here the left hand pole 126 , while the second coil 604 is wound on the second arm 120 .

In use, the first coil 602 is energized to generate a first magnetic flux loop, i.e. the first magnetic field, at pole 126 of the first pole pair, and the second coil 604 is energized to generate a magnetic field at pole 130 of the second pole pair. The second magnetic flux loop, that is, the second magnetic field. Since separate coils are used to generate the first and second magnetic fields, the excitation of the first coil 602 and the second coil 604 can be selected such that the first and second magnetic fields provide different functions when interacting with the food container 200 in use. , eg providing heating and rotation as described above. This arrangement provides two independent magnetic circuits while using a common core back. In some embodiments, the first coil 602 is energized at a higher frequency than the second coil 604 .

An alternative embodiment of a food container 700 for use with the magnetic field generator 104 of FIG. 2 is shown schematically in cross-section in FIG. 13 .

The food container 700 of FIG. 13 is substantially the same as the food container of FIG. 5 except for the form of the food holding basket 702 and the stirrer 704 .

Food holding basket 702 includes a base 706 , sidewalls 708 extending upwardly from susceptor 706 to define housing 710 , and a plurality of legs 712 extending downwardly from base 706 . The length of the legs 712 is such that the base 706 and thus the housing 710 is positioned above the agitator 704 within the receiving space 226 . This divides the receiving space 226 into a liquid storage portion 714 located below the base 706 and a food receiving portion defined by the housing 710 above the base 706 . Base 706 thus acts as a food holding surface. Base 706 and side wall 708 have a plurality of apertures that allow liquid to flow from liquid storage portion 714 to housing 710 and vice versa.

The agitator 704 is of a form sufficient to transfer liquid droplets from the liquid storage portion 714 to the housing as the agitator 704 rotates within the liquid storage portion 714, such as using suitably shaped blades or the like.

In use, food is placed in housing 710, liquid (such as water) is placed in liquid storage portion 714 of food container 700, and food container 700 is placed on food preparation apparatus 100 of Fig. 2, for example, first and second The male magnetic assemblies interact to guide the food container 700 into position on the contact surface 102 of the food preparation apparatus 100 . The food container 700 is positioned on the contact surface 102 such that the susceptor portion 228 of the inner pot 204 covers the poles 126 of the first pair of poles of each core 106, and the non-susceptor portion 230 of the inner pot 204 and the stirrer 704 cover each core The pole 130 of the second pair of poles 106 .

The coils 108 are excited by the excitation means 110 such that first and second flux circuits, ie first and second magnetic fields, are generated at the poles of the first pair of poles 126 and the poles of the second pair of poles 130 of each magnetic core 106 . As mentioned above, the magnetic fields generated at the first pair of poles 126 and the second pair of poles 130 may have different characteristics due to the different reluctances of the first and second flux circuits and the excitation frequency of the coil 108 . In this embodiment, the magnetic field generated at the first pair of poles 126 is a first changing magnetic field, i.e. an alternating magnetic field, which interacts with the susceptor portion 228 such that eddy currents are generated within the susceptor portion 228 and the liquid reservoir 714 liquid is heated.

The magnetic field generated at the second pair of magnetic poles 130 is a second changing magnetic field, i.e. an alternating magnetic field, which interacts with the stirrer 704, such as a magnet of the stirrer 704, causing the stirrer 704 to rotate within the liquid storage portion 714 . Rotation of the agitator 704 within the liquid storage portion 714 transfers droplets of heated liquid from the liquid storage portion 714 to the housing 710 where they contact the food product held within the housing 710 and are used for cooking food. The droplets of the heated liquid may then return to the liquid storage portion 710 through holes formed in the base 706 and side walls 708 of the food holding basket 702 . It should be understood that in some embodiments, the base 706 may not include holes while the sidewall 708 includes holes, or vice versa.

Accordingly, food container 700 may be used in a splash cooking method in which food is cooked via interaction with heated liquid droplets, such as heated water droplets. This type of splash cooking can be relatively energy efficient since no phase change is required, but can often require longer cooking times. Since the food container 700 provides automation of the heating and movement of the agitator, the food container 700 can be left unattended in use, which can facilitate cooking methods such as splash cooking.

Furthermore, the interaction of the food container 700 and the male magnetic assembly of the food preparation device 100 may be effective to lock the food container 700 to the food preparation device 100 such that rotation of the food container 700 relative to the food preparation device 100 is inhibited. This may be particularly beneficial if, for example, the blender is caught by an item falling into the liquid storage portion 714 , which would otherwise cause the food container 700 to rotate relative to the food preparation apparatus 100 . This may allow the food container 700 to be left unattended in use, which is especially advantageous for splash cooking methods which typically take a relatively long time.

When heated droplets are returned to the liquid storage portion 714 in use, a relatively small amount of liquid may be required, thereby increasing liquid efficiency.

The food holding basket 702 and the stirrer 704 are removable from the food container 700 , in particular from the inner pot 204 . This may allow the food container to provide the stirring function of the embodiment of FIG. 2 and the splatter cooking function of FIG. 13 while minimizing the required components, for example by allowing the outer pot 202 and inner pot 204 to be used for both functions. In other embodiments, for example, the food holding basket can be integrally formed with the inner pot 204, and the inner pot 204 can be replaced to provide different functions.

Another alternative embodiment of a food container 800 for use with the magnetic field generator 104 of FIG. 2 is schematically shown in cross-section in FIG. 14 .

Food container 800 shares outer pot 202, lid 206, handle 208, and related features of the food container embodiment of FIG. 5, but differs in the form of inner pot 802 and agitator 804. In some embodiments, the inner pot 802 of the food container of FIG. 14 may have a different diameter than the inner pot 204 of the food container 200 of FIG. 5 . This may allow for a nested arrangement of the inner pots within the outer pot 202 for storage. In use, the food preparation device 100 may sense which inner pot is received within the outer pot 202, or such information may be provided via user input, for example.

The inner pot 802 includes a generally circular base portion 806 and sidewalls 808 extending upwardly from the base portion 806 to define a receiving space 810 . The susceptor portion 806 is hollow and houses the magnetic assembly 812 of the stirrer 804 .

The agitator 804 includes a magnetic assembly 812 and a plurality of chopping blades 814 fixedly attached to the magnetic assembly 812 . A blender 804 as shown in FIG. 14 has a magnetic assembly 812 housed in a base portion 806 of an inner pot 802 and a plurality of chopping blades 814 housed in a receiving space 810 through which a plurality of chopping blades 814 pass through a connector portion 816 Connect to magnetic assembly. However, it should be understood that in other embodiments, the magnetic assembly 812 may include a housing that enables the magnetic assembly 812 and the plurality of shredding blades 814 to be located within the receiving space 810 .

As schematically shown in FIG. 15 , the magnetic assembly 812 includes an annular array of bar magnets 818 . Connection portion 816 is a rigid connection and may include a shaft retained within a bearing assembly.

In use, the food container 800 is placed on the food preparation apparatus 100 of FIG.

The coil 108 is excited by the excitation device 110 so that a magnetic flux circuit, ie a magnetic field, is generated at the pole 126 of the first pair of poles of each magnetic core 106 . In this embodiment, the magnetic field generated at the first pair of poles 126 is a variable, ie, alternating magnetic field, which interacts with the bar magnet 818 of the stirrer 804 to drive the stirrer 804 to rotate, and thus drive the receiving space A plurality of chopping blades 814 within 810 rotate. This allows food, such as vegetables, etc. to be chopped while placed in the receiving space 810 of the food container 800 .

Here, the first pair of poles 126 of the magnetic field generator 104 is used to provide the rotational function, in contrast to the use of the second pair of poles 130 of the magnetic field generator to provide the rotational function for the food container of FIG. 5 . The poles of the first pair of poles 126 are located at a larger radius than the poles of the second pair of poles 130 and thus can provide greater torque, which is beneficial when using the shredding blades 814 .

As schematically shown in FIG. 15 , the food container 800 may also be provided with a convex magnetic assembly 820, which may also be a susceptor material, which interacts with the convex magnetic assembly defined by the magnetic core 106 of the magnetic field generator 104. The lock, for example, interlocks with the poles 130 of the second pair of poles 130 to prevent rotation of the food container 800 relative to the food preparation apparatus 100 in a manner similar to that previously described with respect to the food container 200 of FIG. 5 .

Another alternative embodiment of a food container 900 for use with the magnetic field generator 104 of FIG. 2 is schematically shown in cross-section in FIG. 16 . Here, the food container 900 takes the form of a mixing jug.

The food container 900 includes a cylindrical base portion 902 , a sidewall 904 extending upwardly from the base portion 902 to define a receiving space 906 , a handle 908 , a lip 910 , an agitator 912 and a male magnetic assembly 914 . Lip 910 enables the contents of food container 900 to be poured from receiving space 906, while handle 908 is shaped such that it can be grasped by a user. Here, base portion 902, side walls 904, handle 908, and lip 910 may be formed from a thermally insulating material, such as plastic, as part of a single or multi-step molding process.

Agitator 912 of food container 900 of FIG. 16 is of substantially the same form as agitator 804 of food container 800 of FIG. 14 , in particular comprising an annular array of bar magnets, as schematically shown in the embodiment of FIG. 15 . The base portion 902 is hollow in nature and houses the magnetic assembly 916 of the blender 912 , including a bar magnet, while the chopping blade 918 of the blender 912 is located in the receiving space 906 . The male magnetic assembly 914 has substantially the same structure as the male magnetic assembly 820 shown in FIG. 15 and is embedded in the lower wall of the base portion 902 .

In use, the food container 900 is placed on the food preparation apparatus 100 of FIG. Overlays the poles 130 of the second pair of poles of each core 106 .

The coil 108 is excited by the excitation device 110 so that a magnetic flux circuit, ie a magnetic field, is generated at the pole 126 of the first pair of poles of each magnetic core 106 . In this embodiment, the magnetic field generated at the first pair of magnetic poles 126 is variable, that is, an alternating magnetic field, which interacts with the bar magnet of the stirrer 912 to drive the stirrer 912 to rotate, and thus drives the magnetic field in the receiving space 906 The chopping blade 918 rotates. This allows food, such as vegetables or fruit, to be chopped while placed in the receiving space 906 of the food container 900 . The convex magnetic assembly 914 interacts with the magnetic flux loop (i.e., the magnetic field) generated at the pole 130 of the second pair of poles of each magnetic core 106 to lock the food container 900 to the contact surface 102 of the food preparation apparatus 100, e.g. Rotation of the food container 900 relative to the contact surface 902 is inhibited.

In some embodiments, the food container 900 may be provided with a gear arrangement connecting the magnets of the blender 912 to the plurality of chopping blades 918 . This can provide a further increase in torque while reducing speed.

17 and 18 schematically illustrate another alternative embodiment of a food container 1000 for use with the magnetic field generator 104 of FIG. 2 .

The food container 1000 includes a generally circular base 1002 and sidewalls 1004 extending upwardly from the base 1002 to define a receiving space for containing food. A plurality of filaments 1006 of ferrous material, such as elongated strips of ferrous material, are applied to the base 1002 and side walls 1004 . In particular, each filament 1006 is a continuous filament extending along base 1002 and up to sidewall 1004 . The plurality of filaments 1006 define the susceptor and the plurality of poles P1 - P12 of the male magnetic assembly on the base 1002 .

For example, the continuous nature of filament 1006 can be seen when considering the filaments defining poles P1 and P9. Specifically, filament 1006 extends from an upper region of sidewall 1004 to base 1002 at pole P1, through base 1002 from pole P1 to pole P9, and from pole P9 along sidewall 1004 to the bottom of sidewall 1004. upper area. As shown, the plurality of filaments 1006 extend substantially the entire height of the sidewall 1004 . The plurality of filaments 1006 are positioned along the base 1002 such that the circular area 1008 is located in the center of the base 1002 . The circular region 1008 is formed of a non-susceptor material, such as a non-ferrous material that allows the magnetic field generated by the magnetic field generator 104 to pass through. In use, an agitator, such as agitator 210 of the embodiment of FIG. 5 , may be placed in the receiving space above circular area 1008 .

In use, the food container 1000 is placed on the food preparation apparatus 100 of FIG. The food container 1000 is positioned on the contact surface 102 such that the susceptors defined by the plurality of filaments 1006 overlie the poles 126 of the first pair of poles of each magnetic core 106, and the circular area 1008 of the food container 1000 and the stirrer 210 Overlays the poles 130 of the second pair of poles of each core 106 .

The coils 108 are excited by the excitation means 110 such that first and second flux circuits, ie first and second magnetic fields, are generated at the poles of the first pair of poles 126 and the poles of the second pair of poles 130 of each magnetic core 106 . As mentioned above, the magnetic fields generated at the first pair of poles 126 and the second pair of poles 130 may have different characteristics due to the different reluctances of the first and second flux circuits and the excitation frequency of the coil 108 . In this embodiment, the magnetic field generated at the first pair of magnetic poles 126 is a first changing magnetic field, i.e. an alternating magnetic field, which interacts with the plurality of filaments 1006, causing eddy currents to be generated within the plurality of filaments 1006, and receiving The space is heated. The magnetic field generated at the second pair of poles 130 is a second changing magnetic field, ie an alternating magnetic field, which interacts with the bar magnet 242 of the stirrer (if present) causing the stirrer to rotate within the receiving volume 226 . In this way, the stirrer can be used to stir food received in the receiving space.

Due to the plurality of filaments 1006 extending along the base 1002 and upwards along the sidewall 1004, better heat distribution within the receiving space can be achieved compared to, for example, an arrangement in which the susceptors do not extend upwards along the sidewall 1004. For example, given the presence of multiple filaments 1006, heat may be conducted up sidewall 1004. Because the plurality of filaments 1006 are relatively thin, the thickness of the base 1002 can be reduced, which can facilitate interaction with the magnetic field generated by the magnetic field generator 104, for example by bringing the stirrer 210 closer to the magnetic field generator.

Although not shown here, it should be understood that a layer of insulating material may be provided on the base 1002 and/or the side walls 1004 to improve thermal efficiency and/or increase user safety.

In each of the previously described embodiments of the magnetic field generator, a single ring arrangement of coils and magnetic cores has been described, eg corresponding to a single ring of an induction hob. Induction hobs typically include more than a single ring, and it will be appreciated that the foregoing embodiments of the magnetic field generator may be extended to provide a food preparation device 100 having a multi-ring configuration.

An example of such a polycyclic structure 1100 is schematically shown in FIG. 19 .

Here, four magnetic field generators 104 according to the embodiment of FIG. 2 are positioned as outer ring 1102 . The inner ring 1104 includes an array of C-shaped magnetic cores 1106 that also share the first pair of poles 126 , coils 108 and core backs 114 of each outer ring 1102 . Each C-shaped magnetic core 1106 includes a core back and a plurality of poles 1108 extending upwardly from the core back, for example in a direction towards the contact surface 102 of the food preparation apparatus 100 (towards out of the page in FIG. 19 ). Each core of the C-shaped magnetic core 1106 is back-wound with a corresponding coil 1110 . In use, the coil 1110 of the C-shaped magnetic core 1106 and the coil 108 of the shared magnetic core 106 of the outer ring 1102 may be energized upon receipt of a food container on the contact surface of the food preparation apparatus 100 to provide any of the aforementioned heating, rotating or lock function.

Phase shifting of the PWM can also be applied to the operation of the multi-ring structure 1100 of FIG. 19 when multiple rings are operating simultaneously. Each of these rings can operate at the same or different PWM duty cycle (burst mode control is also suitable) depending on the heating requirements. The interaction of these four loops can be properly controlled to avoid periodic random combinations of coil currents that produce short-term high supply input current values.

While several embodiments of the food container are described herein as having an outer pot, it is understood that the outer pot is an optional feature that may provide increased safety or thermal efficiency, but that the inner pot may be used alone if desired.

Claims (18)

1. A food container for use with food preparation equipment, said food container comprising a base and side walls defining a receiving space for receiving food, a susceptor for heating said receiving space, and a an agitator configured to interact with a first magnetic field of the food preparation device such that the agitator can move within the receiving space, the susceptor is located within the base and is configured to interact with The second magnetic field of the food preparation device interacts such that the receiving space is heated. 2. The food container of claim 1, wherein the susceptor includes a non-susceptor portion aligned with the agitator. 3. The food container of claim 2, wherein the susceptor and the non-susceptor portion are concentrically arranged within the base. 4. The food container according to claim 2 or 3, wherein the non-susceptor portion is arranged at the center of the base, the susceptor extending annularly around the non-susceptor portion. 5. The food container according to any one of claims 1 to 3, wherein the susceptor is centrally arranged on the base and the non-susceptor portion extends annularly around the susceptor. 6. A food container according to any one of the preceding claims, wherein the food container includes a first male magnetic assembly configured so that when the food container is placed on the When on the food preparation device, interacts with the second male magnetic assembly of the food preparation device to inhibit movement of the food container relative to the food preparation device. 7. The food container of claim 6, wherein the first male magnetic assembly comprises an annular ring having a plurality of protrusions extending therefrom. 8. A food container according to claim 6 or 7, wherein the susceptor defines a first male magnetic component. 9. A food container according to any one of the preceding claims, wherein the agitator is removable from the food container. 10. A food container according to any one of the preceding claims, wherein the agitator includes a stirring member for agitating food received in the receiving space. 11. A food product container according to any one of the preceding claims, wherein the blender includes a blade for chopping food product received in the receiving space. 12. The food container according to any one of claims 1 to 9, wherein the receiving space includes a liquid reservoir for receiving liquid and a food receiving portion for receiving food, the agitator being located in the In the liquid reservoir, the susceptor is configured to interact with a first magnetic field to heat the liquid in the liquid reservoir, and the stirrer is configured to interact with the magnetic field so that the stirrer can movement within the container to transfer liquid from the liquid reservoir to the food receiving portion. 13. A food container according to any one of the preceding claims, wherein the susceptor comprises a plurality of continuous filaments extending along the base and upwardly along the side wall. 14. A food container according to any one of the preceding claims, wherein the food container includes an insulating layer provided on the base and the side walls. 15. A food preparation system comprising a food container and a food preparation device according to any one of the preceding claims, wherein the food preparation device comprises a magnetic field generator configured to generate a first magnetic field and the second magnetic field. 16. The food preparation system of claim 15, wherein the magnetic field generator comprises a magnetic core structure, a coil wound around the magnetic core structure, and an excitation device configured to excite the coil, the magnetic field The core structure includes a first magnetic pole pair configured to interact with a susceptor of the food container to define a first magnetic flux path, and the magnetic core structure includes a magnetic pole pair configured to interact with the agitator of the food container to define a second magnetic flux path. The second pole pair for the flux path. 17. The food preparation system of claim 16, wherein the magnetic field generator includes a plurality of first magnetic pole pairs configured to interact with susceptors of the food container to define corresponding first magnetic flux paths, and a plurality of second magnetic pole pairs configured to interact with the agitator of the food container to define respective second magnetic flux paths, the first and second magnetic pole pairs being arranged in a ring. 18. A food preparation system according to any one of claims 15 to 17, wherein the magnetic field generator defines a convex magnetic assembly.

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