COOKING SYSTEM

FIELD OF THE INVENTION

This invention relates to a cooking system, including at least one cooking vessel such as a pot, and a means for heating the vessel, preferably by way of induction heating.

BACKGROUND TO THE INVENTION

Recent technological advances, especially the area of computing, have enabled a significant increase in labour-saving technology, and automation generally.

Such advances have made some contribution to the activity of cooking. For example, many microwave ovens have cooking programs that enable such devices to automatically determine suitable cooking powers and durations, and that enable such devices to cook accordingly, based on information that has been entered into the devices by users. This information may, for example, relate to the type of food product to be cooked and its weight.

In addition, there are many dedicated cooking devices (dedicated in the sense that they are designed for cooking or heating specific types of food) which are automated or which can be pre-programmed to cook for certain periods of time, at certain temperatures and powers, and so on. Examples of such devices are electric kettles with switches that automatically shut off the devices when the water boils, bread makers, and rice makers.

However, the above-mentioned advances have not impacted greatly on the traditional style of cooking in which food is cooked in pots and pans on a stove-top, cooking range or hob. Thus, the methods employed for such cooking are mainly of the traditional type in which the person doing the cooking is required, him- or herself, to regulate or decide on the suitable

cooking power levels, durations, ingredients, quantities, and so on. Consequently, such traditional methods of cooking have not benefited much as a result of the above-mentioned technological advances.

Furthermore, while the dedicated devices mentioned above may provide for automation and simplicity of use, they typically include built-in means for providing power such as electric elements and power cords, batteries, switches, and the like. As a result, such devices often need to be cleaned individually by hand as they cannot be cleaned in sinks or dishwashers. This often negates, at least to some extent, the convenience that such devices provide.

It is an object of the present invention, at least in preferred embodiments, to overcome or ameliorate disadvantages of the prior art, or to provide an alternative thereto.

SUMMARY OF THE INVENTION

According to the invention there is provided a cooking system including: a food vessel for containing a food product, the food vessel having an audible-signal generator for generating an audible actuating signal on the occurrence of a predetermined event; a hob, the hob having a support surface configured to support the food vessel, a heating means configured to heat the food vessel when the food vessel is supported on the support surface, a sensor for sensing a said actuating signal, and a control system configured for controlling operation of the heating means in response to said sensing.

In a preferred embodiment, the predetermined event includes the production of gas, preferably including steam, within the vessel, such that the gas is caused to pass the audible-signal generator thereby to cause said generator to generate the actuating signal. In ONE preferred embodiment, the actuating signal is a dual- tone signal.

In this case, preferably, the actuating signal is an audible signal of a predetermined minimum intensity.

In a preferred embodiment, the control system is configured to reduce the heating of the vessel by the heating means in response to said sensing. In one preferred form of this embodiment, the control system is configured to deactivate the heating of the vessel by the heating means in response to said sensing.

In one preferred embodiment, the cooking system includes a plurality of food vessels, and recognition means configured for enabling the hob to determine which food vessel is supported on the support surface. Preferably the food vessels are of different types.

In this case, in one preferred embodiment, the control system is configured to determine whether to deactivate or reduce heating of the vessel by the heating means in response to said sensing, depending at least partly on the particular type of food vessel that is supported on the support surface.

The cooking system is preferably an induction cooking system in which the hob is configured to heat each vessel supported on the support surface by means of electromagnetic induction.

According to a second aspect of the invention there is provided a cooking system including: a plurality of food vessels for containing food products, the vessels being of different types to one another and each vessel having at least one visible identifier which differs from the at least one visible identifier of each of the other vessels; and a hob, the hob having a support surface configured to support any one of said plurality of food vessels, heating means configured to heat a said food vessel when the food vessel is supported on the support surface, recognition means configured for recognising the least one identifier of each of the food vessels for enabling the hob to determine which type of food vessel is

supported on the support surface, and a control system for controlling operation of the hob depending at least partly on the particular type of food vessel that is supported on the support surface.

In one preferred embodiment, the recognition means includes an optical detection means.

Then, preferably, the at least one visible identifier of each of the food vessels consists of a coloured marker. Preferably each coloured marker is substantially of a single colour. In this case, preferably, the optical detection means is configured to recognise the coloured marker of each of the food vessels by discerning the colour thereof.

In a preferred embodiment, the hob includes at least one user interface for producing at least one of an audible and visible signal. Preferably, the user interface is configured to provide input means to enable a user to make inputs to the cooking system.

In a preferred embodiment, the hob includes a scale to detect a weight of an object on the support surface. Preferably, the hob is configured to calculate a differential between the weight of an object on the support surface at one time and the weight of an object on the support surface at another time.

Preferably, the hob includes at least one microprocessor for performing said calculation.

In a preferred embodiment, the control system is programmable whereby it can be instructed to perform said controlling of said operation of the hob according to at least one predetermined step. Preferably, said predetermined step is dependent at least partly on a weight or weight differential detected by the scale.

According to a third aspect of the invention there is provided a cooking system including:

at least one food vessel for containing a food product; and a hob, the hob having a support surface configured to support the food vessel, heating means configured to heat the food vessel when the food vessel is supported on the support surface, and a scale for detecting the weight of an object on the support surface.

In a preferred embodiment, the hob is configured to calculate a differential between a first weight being the weight of an object on the support surface at one time and a second weight being the weight of an object on the support surface at another time.

Then, preferably, the hob includes a control system configured to determine the weight of the contents of a food vessel supported on the support surface by calculating the difference between said first weight where the object is constituted by the food vessel itself, and said second weight where the object is constituted by the food vessel together with its contents.

In a preferred embodiment, the cooking system according to each of the above aspects of the invention is an induction cooking system in which the hob is configured to heat each vessel supported on the support surface by means of electromagnetic induction.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic side view of a pot according to an embodiment of the invention;

Figure 2 is a schematic plan view of the pot of Figure 1 ; Figure 3 is an enlarged view of the encircled detail of Figure 2;

Figure 4 is a schematic perspective view of a cooking hob according to an embodiment of the invention, for use with the pot of Figure 1 ;

Figure 5 is an schematic exploded perspective view of a kettle and kettle hob according to an embodiment of the invention;

Figure 6 is a schematic side view of the kettle of Figure 5;

Figure 7 is a schematic plan view of the kettle of Figure 6;

Figure 8 is a schematic side view of a pot according to another embodiment of the invention; Figure 9 is a schematic bottom view of the pot of Figure 8;

Figure 10 is a schematic perspective view of a cooking hob according to another embodiment of the invention, for use with the pot of Figure 8;

Figure 11 is a schematic side view of part of a set of cooking vessels according to an embodiment of the invention; Figure 12 is a schematic side view of the remaining part of the set of cooking vessels of Figure 11 ; and

Figure 13 is an schematic exploded partly cut-away side view of a pot being filled during a cooking operation.

DETAILED DESCRIPTION

Referring to Figures 1 to 4, there are shown components of an induction cooking system. This cooking system includes a food vessel in the form of a pot 12, and a hob 14.

The pot 12 includes a receptacle 16 for containing a food product that is to be cooked, a handle extending 18 from the receptacle, and a lid 20.

The hob 14 has defined cooking areas 22, each constituting a support surface for supporting a pot or any other suitable cooking vessel during cooking. The pot 12 is of a metal which is suitable for being heated by the induction cooking process when the pot is located on one of the support surfaces 22.

As in typical induction cookers, the hob 14 includes suitable components (not shown) which are configured to heat the pot 12 (and any other vessels of, or including, suitable metals) by electromagnetic induction. Also as in typical induction cookers, the heating of the pot 12 (or other vessel) in this manner causes food inside the pot to be heated and thus cooked.

Disposed in the lid 20 is an audible-signal generator in the form of a whistle 24 for producing an audible signal. The whistle 24 includes one or more apertures 26 (see Figure 3) and other associated features (not shown). The one or more apertures 26 together with the associated features are adapted to generate a particular audible high-pitched tone as steam is forced through the aperture or apertures. In one preferred embodiment, the whistle 24 is a dual- tone whistle.

The hob 14 is provided with an auditory sensor 28 and a control system 30 (shown schematically in phantom lines) to which the sensor is connected.

In a preferred embodiment the sensor 28 includes a receiver, and is configured for sensing the audible signal generated by the whistle 24, as well as the intensity of the signal. It is configured such that, when it senses the audible signal at or above a predetermined minimum intensity, it sends an actuating signal to the control system 30. The control system 30, in turn, then controls the induction heating operation of the hob 14 so that the heating effect produced on the pot 12 is decreased by a predetermined amount. For example, the heating power may be halved, or it may be completely deactivated.

In an embodiment where the whistle 24 generates a dual-tone signal, as a result of this dual-tone, the risk of the sensor 28 inadvertently responding to individual ambient signals that are not generated by the whistle 24 is minimised.

The cooking system of Figures 1 to 4 may be used for cooking food which, for example, is completely or partially in a liquid form, such as soup. Food in this form is susceptible to boiling over during cooking, which can damage or at least foul the hob 14. However, the embodiment of the invention described in Figures 1 to 4 can assist in minimising this risk.

In particular, as the food in the pot 12 begins to boil, this causes an increase in the steam and other gases generated by the cooking. If the cooking occurs

with the lid 20 in place on the receptacle 16 as illustrated in Figures 1 and 2, the steam and gases are forced through the one or more apertures 26 of the whistle 24, which causes its audible signal to be generated.

As the food is being cooked, during the transition from a non-boiling state to a boiling state, the amount and flow rate of the steam and other gases through the one or more apertures 26 increases, thus causing the intensity of the audible signal also to increase. When the intensity reaches the above- mentioned minimum intensity at which the sensor 28 sends an actuating signal to the control system 30, the control system controls the operation of the induction heating of the pot 12 so as to decrease or deactivate the heating. In this manner, the heat is turned down so as to decrease the energy available for heating the pot 12 and cooking the food in its receptacle 16.

Consequently, the food is allowed to return from a state of boiling or partial boiling to a state of non-boiling, and the risk of the food boiling over is minimised.

Referring to Figures 5, 6, and 7, there is shown another cooking system, designated 40. Features in these figures corresponding to features in Figures 1 to 4 are indicated by similar reference numbers to those of Figures 1 to 4 but with the addition of the suffix ".1".

The cooking system 40 includes a water kettle 42 and a hob 14.1 which serves as a base for the kettle. Accordingly the hob 14.1 is referred to below as a base.

Unlike conventional electric kettles in which the base includes electric contacts for energising an element in the kettle, the embodiment shown in Figures 5 to 7 is of the induction cooking type as described above. Thus, the kettle 42 is, or includes components, of a metal which is suitable for being heated by the induction heating process.

In particular, the kettle base 14.1 , as in the case of the hob 14 of Figure 4, includes components (not shown) which are configured to heat the kettle 42, or its relevant metal parts, by the induction heating process, involving electromagnetic induction, when the kettle is supported on the appropriate area of the base which constitutes a support surface 22.1.

The base 14.1 includes a hub 44 which can be accommodated in a complementary recess (not shown) in the bottom of the kettle 42 for suitably locating the kettle in relation to the support surface 22.1.

The kettle 42 includes a handle 46 and a spout 48. Disposed within the spout 48 is a whistle 24.1 similar to the whistle 24 of Figures 1 to 4. The base 14.1 includes a sensor 28.1 and control system 30.1 (shown schematically in phantom lines), which are similar to the sensor 28 and control system 30, respectively, of the embodiment of Figures 1 to 4.

The operation of the kettle 42 is similar to that of the pot 12 described above. In particular, the water in the kettle 42 is heated by the induction process in which the base 14.1 heats the relevant metal parts of the kettle. As the water in the kettle 42 begins to boil, the steam that is generated is forced through one or more apertures (not shown in Figures 5 to 7) of the whistle 24.1 , and this causes an audible signal to be generated.

When the state of boiling has progressed sufficiently, the intensity of this signal reaches the predetermined minimum intensity at which the sensor 28.1 sends an actuating signal to the control system 30.1. The control system 30.1 , in turn, shuts off the induction heating that is being effected by the base 14.1. Thus the kettle 42 is effectively "switched off".

Accordingly the cooking system of Figures 5 to 7 can be used to boil water as is typically done by a conventional electric kettle.

Referring to Figures 8 to 13, there is shown a further cooking system. Features in these figures corresponding to features in Figures 1 to 4 and

Figures 5 to 7 are indicated by similar reference numbers to the corresponding features of those figures but with the addition of the suffix ".2".

The cooking system of Figures 8 to 13 includes a pot 12.2 as well as a set of other cooking vessels of different types as illustrated in Figures 11 and 12.

These vessels include a fish plate 62, a steamer 64, pots 66 (only one of which is shown) of different sizes to the pot 12.2, a skillet 68, a wok 70, a kettle 42.2, a rice cooker 72, a deep-fryer 74, and a slow-cooker 76. While this cooking system includes the types of cooking vessels shown, it is to be understood that other embodiments of the cooking system may include other types of vessels.

It is also to be understood that, where reference is made in this specification to the vessels being of different types, this includes vessels of the same basic type (such as a pot) but being of different dimensions or proportions.

Each of the vessels of the embodiment of Figures 8 to 13 is of a type suitable for induction cooking as described above. Thus each vessel is, or includes parts, of a metal which is suitable for this purpose.

The hob 14.2 includes a user-interface display and control panel 78 for presenting readable information to a user. Thus, the panel 78 may include a touch control (not shown) for enabling the user to press suitable areas of the panel which are demarcated as buttons by the particular application of the cooking system being used (as controlled by the control system 30.2, which is shown schematically in phantom lines in Figure 10), or it may have dedicated buttons.

In addition, the hob 14.2 is provided with a further user-interface in the form of a speaker 82 for providing audible messages to the user.

The pot 12.2, on its under-surface, includes a marker 84 of a particular colour (for example, red). Each of the other vessels of Figures 11 and 12 includes a similar marker (not shown) on its under-surface, except that the colours of the

markers of the various vessels differ from one another. Thus each coloured marker 84 of the vessels (including of the pot 12.2) constitutes a unique marker among the entire set of vessels.

The hob 14.1 includes an optical sensor 86 in the centre of each of the support surfaces 22.2. Each optical sensor 86 includes suitable circuitry (not shown) which is configured to identify each of the colours of the various markers 84. In one embodiment, the optical sensor 86 is capable of discerning 24 different colours.

As each marker 84 is unique among the set of vessels of the embodiment of Figures 8 to 13, by identifying the relevant marker colour, each optical sensor 86 is effectively able to identify the type of vessel that is placed on the support surface 22.2 in which that optical sensor is located. Each marker 84 may therefore be regarded as an identifier of the particular vessel and each optical sensor 86 may be regarded as a vessel recognition means.

The upper part 88 of the hob 14.2 as shown is movable relative to a base part 90 of the hob, with the upper part being supported on suitable weight- detection means (not shown). Thus the upper part 88 of the hob 14.2 constitutes a scale. For convenience, the upper part 88 of the hob 14.2 is referred to below as the scale. In another embodiment (not shown) the areas constituting the support surfaces 22.2 are each individual scales.

As described in more detail below, the ability of the hob 14.2 to identify the type of food vessel supported on the support surface 22.2 enables the hob to control its operation, depending, at least partly, on the type of vessel that is supported. This may be described in relation to the following example, in which the cooking system of Figures 8 to 13 incorporates a cooking system of the type described in relation to Figures 1 to 4.

The pot 12 of the cooking system of Figures 1 to 4 is constituted in the present embodiment by the pot 12.2. In addition, the cooking system of Figures 8 to 13 incorporates a cooking system of the type described in relation

to Figures 5 to 7. The kettle 42 of that cooking system is constituted in the present embodiment by the kettle 42.2.

In this example, each of the pot 12.2 and kettle 42.2 of the present embodiment is provided with a whistle corresponding to the whistles 24 and 24.1 , respectively, and the hob 14.1 is provided with an auditory sensor corresponding to the auditory sensors 28 and 28.1 (the whistles and auditory sensors not being shown in Figures 8 to 13).

In this example, the cooking system of Figures 8 to 13, when used with the pot 12.2, is configured to simply reduce the heating of the pot to avoid boiling over of its contents but to allow sufficient heat for the contents to continue to simmer. However, when used with the kettle 42.2, it is configured to completely shut off the kettle once the water has boiled (as is the case with conventional electric kettles).

As the pot 12.2 and kettle 42.2 have markers 84 of different colours, each optical sensor 86 is able to determine which of the pot and kettle is placed on the relevant support surface 22.2.

The control system 30.2 in this example includes suitable memory and microprocessors (not shown), and is programmed such that, if the pot 12.2 is the vessel on the support surface 22.2 and the pot's whistle begins to emit its audible signal at the minimum predetermined intensity as described above, the control system simply causes the hob 14.2 to reduce the heating of the pot (for example by reducing the heating power to half of what it was). Thus the hob 14.2 can continue heating the pot 12.2 and its contents but not sufficiently to cause boiling over.

On the other hand, if the kettle 42.2 is the vessel on the support surface 22.2 and the kettle's whistle begins to emit its audible signal at the minimum predetermined intensity as discussed above, the control system 30.2 causes the hob 14.2 to completely shut off the heating of the kettle.

The above example illustrates how the ability of the hob 14.2 to identify the type of cooking vessel supported on the support surface can be used to determine the nature of the operation of the hob in relation to the cooking process.

The presence of the scale 88 provides the cooking system of Figures 8 to 13 with further capabilities. This will first be described in relation to the above example pertaining to the kettle 42.2.

When the kettle 42.2 is placed on one of the support surfaces 22.2 with water in the kettle, or as water is added to the kettle, the hob 14.2 is able to determine the quantity of water in the kettle by the mass of water in the kettle. The way that this is achieved is described in relation to this example as follows.

The weight of the kettle 42.2 itself is stored in the memory of the control system 30.2. When the kettle 42.2 and its water contents are placed on the support surface 22.2, the scale components of the hob 14.2 enable the overall weight of the kettle and its contents to be determined. The control system 30.2 then effectively subtracts the weight of the kettle 42.2 from the overall weight of the kettle and water, and this indicates the weight of the water alone in the kettle.

It will be appreciated that this ability to determine weight of contents of a cooking vessel can be employed in a similar manner in relation to each of the types of vessel forming part of the cooking system of Figures 8 to 13. This requires that data relating to each of the cooking vessels (such as their weight) must be pre-programmed and stored in the memory of the control system 30.2.

Continuing with the above example pertaining to the kettle 42.2, in a preferred embodiment, the control system 30.2 is programmed to display, on the display and control panel 78, the volume of water in the kettle 42.2, for example as a number of cups or millilitres. Its processor can calculate the volume by taking

account of the measured weight of the water and the known density of water, which is also pre-programmed and stored in the memory of the control system 30.2.

It will be appreciated that, in order for the control system 30.2 to "know" that the substance in the pot 12.2 (or being placed in the pot) is water, the user needs to enter such information into the control system 30.2. To this end, in a preferred embodiment, the display and control panel 78 demarcates certain areas to constitute suitable buttons which are suitably labelled. This allows the user to "inform" the control system 30.2 that the substance is water so that the calculations that are carried out to determine the weight of the water are based on the properties of water and not, for example, some other substance.

With the cooking system of Figures 8 to 13 including many different types of vessels as described above, in one preferred embodiment the information displayed on the display and control panel 78, including buttons that are provided by way of demarcated areas on the panel, is based on the type of vessel which the optical sensor 86 identifies as being supported on the relevant support surface 22.2. For instance, in the above example relating to the kettle 42.2, the information and buttons provided may relate specifically to the function and purpose of a kettle, such as the amount of water in the kettle and the number of cups that can be filled, buttons for allowing the user to enter a desired heating temperature, and so on.

Continuing with the above example in relation to the kettle 42.2, once the water in the kettle has boiled, the control system 30.2 causes the power to the kettle to be shut off. However, as an alternative, it may simply reduce the power and maintain the temperature of the water in the kettle 42.2 at a suitable level for making tea or coffee.

To enable this, when the hob 14.2 identifies the vessel on the support surface 22.2 as being the kettle 42.2 in the manner described above, then, as mentioned above it can present information on the display and control panel 78 which is specific to the kettle. In particular it displays demarcated areas

which are configured as buttons to allow the user to enter kettle-orientated data. For instance, the control system 30.2 may be programmed for the display and control panel 78 to present text asking the user what products the water is to be used to make, and possibly providing options such as "tea", "coffee" and so on, and allowing the user to press the appropriate buttons in the appropriate manner to make a selection.

It is often regarded as preferable to prepare and drink tea at a higher temperature than coffee. Accordingly, if the user selects tea as the beverage to be made, the control system 30.2 may be pre-programmed to maintain the water in the kettle at a suitable temperature for this purpose. In particular, once the water in the kettle 42.2 has boiled (as indicated by the audible signal of the whistle 24.2 and sensed by the auditory sensor 28.2), the control system 30.2 automatically causes the heating of the kettle to be reduced to a level at which the temperature of the water therein can be maintained at, say, 95 degrees.

On the other hand, if the selected beverage is coffee, then a similar process can be used to maintain the temperature of the water at, say, 86 degrees.

Once the water has reached the desired drinking temperature, the control system 30.2 causes a suitable message to this effect to be displayed on the display and control panel 78, and also a suitable audible message to be emitted from the speaker 82 - for example announcing that the water is ready to make tea.

One means by which the control system 30.2 may determine the temperature of the water in the kettle 42.2 is to use information in its memory regarding such data as heat transfer coefficients of water and of the materials from which the kettle is made, the amount of water in the kettle (based on its weight as described above), the amount of energy added to the kettle by the induction cooking process, and the ambient temperature in the area in which the cooking system is located. With these factors known, the processing required by the control system 30.2 to determine the temperature of the water

in the kettle 42.2 should be reasonably straightforward and can be carried out at least partly by the control system's microprocessor.

The above features of the cooking system of Figures 8 to 13 will now be described in relation to further examples for illustrating how the relevant embodiments of the invention can be used for effecting "smart cooking".

First, it will be appreciated that the control system 30.2 can be preprogrammed with data pertaining to a large variety of food products such as water, milk, sugar, flour, specific types of vegetables, specific types of meat, rice, and so on. The types of information that may be stored may include aspects such as density, heat coefficients, melting temperatures, and so on. In addition, the control system 30.2 may be pre-programmed with recipes, and allow a pro-active approach between the cooking system and the user during the process of cooking while following a recipe.

If a user wishes to add a certain quantity of a type of product to a cooking vessel where data relating to such a product has previously been entered into the control system 30.2, then the control system can alert the user when the desired quantity has been added. For example, as illustrated in Figure 13, if a user wishes to boil milk in a pot, then the first step may be to place the pot 12.2 on one of the support surfaces 22.2. As the pot 12.2 is placed on the support surface 22.2, the optical sensor 86 will identify the type of cooking vessel by the coloured marker 84 on the pot's base. The control system 30.2 can then determine the weight of the pot 12.2 by use of the scale 88 and the data stored in the control system's memory. As described above, once the weight of the pot 12.2 is known, then the weight of the contents added to the pot can also be determined by effectively subtracting the weight of the pot from the overall weight of the pot and its contents as determined by the scale 88.

Thus, in one scenario, the user may press the relevant buttons on the display and control panel 78 to indicate that the product to be poured into the pot 12.2 is milk. As the milk is poured, for example from a jug 92 as indicated at 94, the

display and control panel 78 will indicate the weight of the milk in the pot 12.2 and/or the volume thereof (based on the known density of milk and calculations carried out by the control system 30.2).

In another scenario, the desired quantity of milk may be part of a recipe and the display on the panel 78 may then also inform the user when the desired quantity of milk has been poured into the pot 12.2 as part of the relevant recipe step.

Similarly, if for example a recipe calls for a cup of flour to be added, then the control system 30.2 can determine the volume of flour in the cooking vessel from the weight of the flour.

Another example relates to the making of tea or coffee as described above. With the cooking vessel identified by the sensor 86 as being the kettle 42.2, and the contents known to be water, the amount of water in the kettle can be determined. Thus the display and control panel 78 can indicate to the user the amount of water in the kettle - e.g. four cups. Thus the user will know whether there is a sufficient quantity of water in the kettle 42.2 to make the desired number of cups of tea or coffee.

Another example will now be described. In this example, the product to be cooked is soup (for example potato and leek soup). This example illustrates how the cooking system of Figures 8 to 13 may be used to a achieve a greater level of interactivity between the user and the cooking system of Figures 8 to 13.

First, the user uses the appropriate controls on the display and control panel 78 to indicate that the product to be made is potato and leek soup. To achieve this, the display and control panel 78 may have certain constant buttons for operating a menu, and accessing desired recipes. The control system 30.2 will recognise the selection of leek and potato soup provided the recipe for this type of soup has been previously programmed into the control system.

Once the user has "informed" the control system 30.2 of the product to be made, the display and control panel 78 indicates to the user the appropriate cooking vessel to be used - e.g. "pot no. 3". When the user places the relevant pot on the support surface 22.2, the sensor 86 can identify the pot and confirm that it is the correct vessel. The control system 30.2 may be programmed such that, if the incorrect vessel is used, the control system will not enable the user to proceed with the recipe.

With the correct pot in place, the display and control panel 78 may then inform the user of the next recipe step - e.g. "add 30Og of leeks". Provided that suitable data relating to the required ingredients has been pre-programmed into the control system 30.2, then by means of the scale 88, the control system can determine the relevant quantity of each ingredient that is being added and whether this meets the desired quantity. Thus, as the leeks are added, the scale 88 can determine the weight and the control system 30.2 can calculate the different between the weight at any time and the weight that had been measured by the scale immediately before the adding of the leeks began. This weight differential reflects the weight of the leeks in the pot.

From the known density of leeks, the volume of leeks added to the pot can also be determined.

Once the desired quantity of leeks has been added, the display and control panel 78 can inform the user that the pot contains the desired quantity of leeks and can then proceed to the next recipe step - e.g. "add 1 cup of chopped onions".

A similar process to that described for the leeks can be used for the onions and all other ingredients to be added.

If for example, the recipe calls for heating or cooking at a certain temperature and duration to take place, then the cooking system of Figures 8 to 13 can carry out the necessary steps automatically. For example, once the leeks and onions have been added, the display and control panel 78 may provide a

message such as "wait - existing ingredients to be heated". Then, the control system 30.2 can cause the hob 14.2 to heat the pot and its contents to a desired extent and for a desired length of time before providing further recipe instructions to the user.

At the end of the cooking process, the display and control panel 78 may indicate, for example, "soup is ready".

For each of the types of information presented on the display and control panel 78, there may be a corresponding audible message emitted by the speaker 82.

While the above example of making soup has been described in relation to the use of a pot, the control system 30.2 may be similarly programmed with recipes for which the other vessels shown in Figures 11 and 12 may be suitable. The nature of interactivity between the control system and the user - for example the type of messages presented on the display and control panel 78, the types of input required by the user and so on - will depend on the requirement of the recipe, or type of vessel in each case.

The vessels shown in Figure 12 are all of types that are conventionally provided with their own means for receiving power, such as electric elements, power cords and so on. However, the requirement for such means for receiving power is avoided in the present invention due to the fact that the induction cooking system is used. As a result, such vessels, unlike the conventional versions, may be suitable for washing in dishwashers or immersing in water. This requires, however, that the vessels are, or have appropriate parts, of suitable metals that will be heated by the induction heating process.

In a preferred embodiment, the cooking system of Figures 8 to 13 is provided with suitable interfaces for enabling the transfer of information such as data relating to food substances, recipes and so on, to the control system 30.2. For

example, the cooking system may include a USB port or a Bluetooth interface to allow data to be downloaded from a computer or the internet.

Although the invention is described above in relation to particular embodiments, it will be appreciated by those skilled in the art that it is not limited to those embodiments but may be embodied in many other forms, some of which are described below.

For example, the hob may form part of an in-built unit or a portable unit.

In addition, although the invention has been described in relation to the induction heating process, other forms of heating may be used instead where possible, such as conventional electric heating, gas heating or halogen heating.

Furthermore, while the coloured markers described above are described as being of a particular colour, other suitable markers may be used, such as markers having particular shapes or colour combinations, markers in the form of bar-codes, and so on. The markers need not be on the bases of the cooking vessels but can be in another suitable locations such as the sides, or the entire vessels or large parts of them can constitute the markers. In addition, means of sensing such markers other than optical sensors may be used, depending on the nature of the markers, such as buttons or other deformable or movable elements.

As another alternative, while the cooking systems are described above as involving degrees of automation, they may be provided with suitable override facilities to allow the user to depart from the pre-programmed steps, such as recipe steps, or to use the components in an ad hoc manner. For example, the whistles may be switchable between an "on" position in which they can generate their audible signals and an "off" position when these signals are not required.