Heating device

Abstract

There is described a heating device comprising: a cavity; a perforated chamber, the perforated chamber being mountable within the cavity of the heating device; heating element for causing a heating of a substance in the cavity and / or the perforated chamber; wherein the heating element is arranged to cause boiling of a fluid within the perforated chamber.

Description

[0001] Heating device

[0002] Field of the invention

[0003] The present invention relates to a heating device as well as a method of operating a heating device. In particular, the heating device may comprise a chai maker.

[0004] Background to the Disclosure

[0005] Heating devices used for numerous purposes; for example, kettles are often used to boil water, and espresso machines are used to heat water and to combine this water with coffee grounds so as to produce coffee. Such heating devices often lack versatility, are difficult to control precisely, and / or are difficult to maintain.

[0006] Summary of the Disclosure

[0007] According to at least one aspect of the present disclosure, there is described a heating device comprising: a cavity for receiving a substance; a heating element for heating the substance; a multiphase level sensor for determining a level in the cavity of each of a plurality of component substances of the substance; and a control unit for controlling the heating element in dependence on one or more of the determined levels.

[0008] Preferably: the multiphase level sensor is arranged to determine a level in the cavity of a froth; and the control unit is arranged to control the heating level in dependence on the determined level of froth.

[0009] Preferably, the control unit is arranged to control the heating level in dependence on the determined level of froth exceeding a first threshold level. Preferably, the control unit is arranged to control the heating level in dependence on the determined level of froth falling below a second threshold level.

[0010] Preferably, the control unit is arranged to control the heating element in dependence on the highest level present in the cavity.

[0011] Preferably, the multiphase level sensor comprises one or more of: one or more mechanical floats; one or more optical sensors; one or more cameras; one or more acoustic sensors; one or more temperature sensors; one or more density sensors; one or more pressure sensors; and one or more conductive sensors.

[0012] Preferably, the multiphase level sensor comprises a driving probe and a receiving probe, wherein the driving probe is arranged to transmit an electric signal to the receiving probe via the substance.

[0013] Preferably, the control is unit arranged to determine a resistance of the substance, and / or of one or more component substances, based on the signal received by the receiving probe. Preferably, the control unit is arranged to determine a resistance of the substance based on a magnitude, phase shift, current, and / or voltage of the received signal.

[0014] Preferably, the driving probe is arranged to transmit an alternating current (AC) signal.

[0015] Preferably, the receiving probe comprises a plurality of separated contacts at different heights in the cavity so as to enable the determination of the resistance of different layers of the substance.

[0016] Preferably, the driving probe and the receiving probe are located on a shared structure and are electrically isolated by an intermediate material.

[0017] Preferably, the driving probe and the receiving probe are located on different structures.

[0018] Preferably, the control unit is arranged to determine one or more of: a phase, a density, and / or a temperature of one or more of the component substances of the substance based on a reading from the multiphase level sensor.

[0019] Preferably, a / the control unit is arranged to determine one or more of: whether a (e.g. highest) level of the substance exceeds a maximum threshold level; and / or whether a (e.g. lowest) level of the substance is below a minimum threshold level.

[0020] Preferably, the multilevel phase sensor is arranged to determine the levels based on one or more of: a property of the substance; a change in a property of the substance; and a change in a property of the substance following a heating of the substance.

[0021] Preferably, the heating device comprises an agitator for mixing the substance. Preferably, the agitator is arranged to mix the substance in dependence on one or more of the determined levels.

[0022] Preferably, the agitator comprises a physical structure and / or a high pressure jet.

[0023] Preferably, the control unit is arranged to determine a temperature of the substance and / or or of one or more of the component substances based on a determination of a change in the temperature of the substance that occurs when a unit input of power is provided to the heating element (e.g. dT / dP). According to another aspect of the present disclosure, there is described a control unit of a heating device, wherein the heating device comprises a cavity for receiving a substance and a hearing element for heating the substance, and wherein the control unit is arranged to determine a temperature of the substance based on a determination of a change in the temperature of the substance that occurs when a unit input of power is provided to the heating element (e.g. dT / dP).

[0024] Preferably, the heating device comprises one or more sensors for sensing a property of the substance. Preferably, the heating device comprises one or more sensors for sensing a property of one or more of the component substances of the substance. Preferably, the heating device comprises an array of sensors for sensing properties of a plurality of the component substances.

[0025] Preferably, the control unit is arranged to control the heating element in dependence on the sensor.

[0026] Preferably, the sensor comprises one or more of: a temperature sensor; a pressure sensor; and a density sensor.

[0027] Preferably, the heating device comprises comprising a lid. Preferably, the lid is removable and / or detachable.

[0028] Preferably, the multiphase level sensor is integrated with, and / or attached to, the lid. Preferably, the heating element is integrated with, and / or attached to, the lid.

[0029] Preferably, the heating device comprises a user interface, wherein the user interface is arranged to: report one or more of the levels; and / or indicate that a heating process is complete; and / or indicate, based on the substance, a product, and / or an amount of a product that may be produced.

[0030] Preferably, the control unit is arranged to control the heating element in dependence on a user input. Preferably, the control unit is arranged to transfer one or more materials to the cavity. Preferably, the control unit is arranged to transfer the materials in dependence on one or more of the determined levels and / or in dependence on whether a component substance is boiling or near boiling.

[0031] Preferably, the control unit is arranged to transfer the materials in an order that depends on a user input.

[0032] Preferably, the heating device comprises a spout for dispensing the substance from the cavity.

[0033] Preferably, the heating device comprises a filter for filtering the substance. Preferably, the filter is located adjacent a / the spout.

[0034] Preferably, the heating device comprises a cleaning mechanism for cleaning the multiphase level sensor, the cavity, and / or the heating element.

[0035] Preferably, the heating device comprises a heating element that is arranged to provide a greater heating output towards a central portion than at an outer portion. More preferably, the heating device comprises a spiral heating element, yet more preferably a logarithmic spiral heating element.

[0036] Preferably, the heating element comprise a recessed section, preferably a recessed section for accommodating and / or securing the perforated chamber.

[0037] Preferably, the heating device is one or more of: a kitchen appliance; a food processor; a soup maker and a beverage maker.

[0038] Preferably, the heating device is a chai maker.

[0039] Preferably, the heating device is arranged to receive a capsule containing the substance.

[0040] According to another aspect of the present disclosure, there is described a heating device comprising: a cavity; a perforated chamber, the perforated chamber being mountable within the cavity of the heating device; a heating element for causing a heating of a substance in the cavity and / or the perforated chamber; wherein the heating element is arranged to cause boiling of a fluid within the perforated chamber.

[0041] Preferably, the perforated chamber is arranged to be mountable so as to be in thermal contact with a contact surface of the heating device, the contact surface being associated with the heating element.

[0042] Preferably, the perforated chamber comprises a thermal interface, the thermal interface being arranged to contact a contact surface of the heating device.

[0043] Preferably, the perforated chamber comprises a sealing structure, the sealing structure being arranged to form a seal between the perforated chamber and a contact surface of the heating device. Preferably, the sealing structure comprises an O-ring.

[0044] Preferably, the contact surface is located adjacent the heating element of the heating device.

[0045] Preferably, the contact surface comprises a ferrous surface. Preferably, the ferrous surface is arranged to be heated by an inductive heating element of the heating device.

[0046] Preferably, the perforated chamber is removably mounted within the heating device. Preferably, the heating device comprises a biasing structure, the biasing structure being arranged to urge the perforated chamber (e.g. a / the thermal interface and / or a / the sealing structure) into contact with the contact surface.

[0047] Preferably, the biasing structure is arranged to interact with the remainder of the perforated chamber such that mounting the perforated chamber within the heating device causes the biasing structure to urge a / the thermal interface and / or a / the sealing structure into contact with the contact surface. Preferably, the biasing structure is arranged to interact with a lid of the perforated chamber such that inserting the lid of the biasing structure into the heating device causes the biasing structure to urge a / the thermal interface and / or a / the sealing structure into contact with the contact surface.

[0048] Preferably, the heating element comprises an inductive heating element, the inductive heating element being arranged to inductively heat the perforated chamber.

[0049] Preferably, the perforated chamber is arranged to fit into a recess of the heating device and / or a / the contact surface.

[0050] Preferably, the walls of the perforated chamber comprise apertures, preferably apertures with a size of between 0.02mm and 0.5mm.

[0051] Preferably, the perforated chamber comprises a stainless steel and / or nickel mesh.

[0052] Preferably, the heating device comprises an inner liner that is removable from the perforated chamber. Preferably, the inner liner comprises apertures that are smaller than apertures of the walls of the perforated chamber.

[0053] Preferably, the perforated chamber comprises a lid. Preferably, the lid comprises a mounting structure. Preferably, the mounting structure comprises a threaded structure.

[0054] Preferably, the heating comprises a structure for selectively mounting one a plurality of perforated chambers.

[0055] Preferably, the heating device comprises a plurality of perforated chambers that are mountable within the heating device.

[0056] Preferably, the plurality of perforated chambers are associated with one or more of: different axial lengths; and apertures of different sizes.

[0057] Preferably, the plurality of perforated chambers are associated with different uses. Preferably, or more of the perforated chambers is suitable for: brewing chai; and / or steaming vegetables; and / or steaming rice.

[0058] Preferably, the heating device is IP-rated such that the heating device can be washed in a dishwasher.

[0059] Preferably, the control unit is arranged to determine a temperature of a substance within the heating device and / or the perforated chamber. Preferably, the control unit is arranged to determine a temperature of one or more component substances of the substance.

[0060] Preferably, the control unit is arranged to determine the temperature based on a change in the temperature of the substance that occurs when a unit input of power is provided to the heating element (e.g. dT / dP).

[0061] Preferably, the heating device comprises: a multiphase level sensor for determining a level in the cavity and / or the perforated chamber of each of a plurality of component substances of the substance; and a control unit for controlling the heating element in dependence on one or more of the determined levels.

[0062] Preferably, the heating device comprises the control unit is arranged to control the heating element in dependence on the highest level present in the cavity.

[0063] Preferably, the multiphase level sensor is arranged to determine a level in the cavity of a froth; and the control unit is arranged to control the heating level in dependence on the determined level of froth.

[0064] Preferably, the control unit is arranged to control the heating level in dependence on: the determined level of froth exceeding a first threshold level; and / or the determined level of froth falling below a second threshold level.

[0065] Preferably, the control unit is arranged to determine one or more of: a phase, a density, and / or a temperature of one or more of the component substances of the substance based on a reading from the multiphase level sensor.

[0066] Preferably, a / the control unit is arranged to determine one or more of: whether a (e.g. highest) level of the substance exceeds a maximum threshold level; and / or whether a (e.g. lowest) level of the substance is below a minimum threshold level.

[0067] According to another aspect of the present disclosure, there is described a perforated chamber for use with a heating device, the perforated chamber comprising: a mounting structure for mounting the perforated chamber in a cavity of the heating device such that the operation of the heating element is arranged to cause boiling of a fluid within the perforated chamber.

[0068] According to another aspect of the present disclosure, there is described a structure, preferably a lid, arranged to be retrofitted to a heating device, the structure comprising the aforesaid perforated chamber.

[0069] According to another aspect of the present disclosure, there is described a system comprising a heating device and at least one perforated chamber.

[0070] According to another aspect of the present disclosure, there is described a kit of parts comprising a heating device and at least one perforated chamber.

[0071] Preferably, the system or the kit of parts comprises a plurality of perforated chambers. Preferably, each of the plurality of perforated chambers is associated with one or more of: different axial lengths; and apertures of different sizes.

[0072] According to another aspect of the present disclosure, there is described a capsule for the aforesaid heating device. Preferably, the capsule comprises a chai mix.

[0073] According to another aspect of the present disclosure, there is described a multiphase level sensor for: determining a level of a plurality of component substances in a cavity; and controlling a heating element in dependence on one or more of the determined levels.

[0074] According to another aspect of the present disclosure, there is described a structure arranged to be retrofitted to a heating device, the structure comprising the aforesaid multiphase level sensor, the structure preferably further comprising the heating element.

[0075] Preferably, the structure comprises a lid for the heating device.

[0076] According to another aspect of the present disclosure, there is described a kit of parts comprising: a heating device comprising: a cavity for receiving a substance; and a heating element for heating the substance; a multiphase level sensor for determining a level in the cavity of a plurality of component substances of the substance; and a control unit for controlling the heating element in dependence on one or more of the determined levels.

[0077] According to another aspect of the present disclosure, there is described a method of operating a heating device comprising a cavity and a heating element, the method comprising: detecting a substance in the cavity; determining a level in the cavity of each of a plurality of component substances of the substance; and controlling the heating element in dependence on one or more of the determined levels.

[0078] According to another aspect of the present disclosure, there is described a method of determining a temperature of a substance in a cavity based on a determination of a change in the temperature of the substance that occurs when a unit input of power is provided to a heating element arranged to heat the substance (e.g. dT / dP).

[0079] Preferably, the method comprises changing a power provided to the heating element based on the determined temperature.

[0080] According to at least one aspect of the present disclosure, there is described a heating device (e.g. a kettle) which is capable of distinguishing a froth layer from a liquid layer and modulate heating in such a way as to prevent an overspill event.

[0081] The froth layer may be detected via any single or combination of means including a mechanical float, optical sensor, camera, acoustic sensor, temperature sensor (s) or conductive sensor(s).

[0082] An array of conductive sensors may be arranged on a probe with exposed contacts.

[0083] An electrical signal may be applied to the exposed contacts in order to determine an impedance level at different liquid / froth levels.

[0084] The signal may be an AC waveform.

[0085] The level sensors may protect against an overflow event.

[0086] The level sensors may protect against a dry heating event.

[0087] A heating element may be modulated in response to the liquid / froth levels to allow for brewing without overflowing of froth layer.

[0088] A user interface may report the level of chai brew available to the user through a user interface. Any feature described as being carried out by an apparatus, an application, and a device may be carried out by any of an apparatus, an application, or a device. Where multiple apparatuses are described, each apparatus may be located on a single device.

[0089] Any feature in one aspect of the disclosure may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa.

[0090] Furthermore, features implemented in hardware may be implemented in software, and vice versa. Any reference to software and hardware features herein should be construed accordingly.

[0091] Any apparatus feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure, such as a suitably programmed processor and associated memory.

[0092] It should also be appreciated that particular combinations of the various features described and defined in any aspects of the disclosure can be implemented and / or supplied and / or used independently.

[0093] The disclosure extends to methods and / or apparatus substantially as herein described with reference to the accompanying drawings.

[0094] The disclosure will now be described, by way of example, with reference to the accompanying drawings.

[0095] Description of the Drawings

[0096] Figures 1 a and 1 b show views of a heating device for heating a substance.

[0097] Figure 2 shows an embodiment of a multiphase level sensorthat may be used with the heating device.

[0098] Figure 3 shows aspects of the operation of the multiphase level sensor of Figure 2.

[0099] Figure 4 shows a computer device that may be used with the heating device.

[0100] Figure 5 shows a method of providing a signal to a heating element of the heating device in dependence on a reading from a multiphase level sensor.

[0101] Figures 6a, 6b, 6c, and 6d show embodiments of a heating device that comprises a perforated chamber.

[0102] Figures 7a and 7b show embodiments of a heating device comprising a perforated chamber.

[0103] Figure 8 shows an embodiment of a perforated chamber.

[0104] Figures 9a and 9b show further embodiments of a heating device comprising a perforated chamber.

[0105] Figures 10a, 10b, and 10c show yet further embodiments of a heating device comprising a perforated chamber.

[0106] Figures 11 a, 11 b, and 11c show a logarithmic spiral heating element.

[0107] Description of the preferred embodiments

[0108] Referring to Figure 1a, there is shown a heating device 100 that comprises a wall 102. The wall surrounds a cavity, where a user is able to place a substance into the cavity. To enable the user to place a substance into the cavity, the wall may comprise, or may provide, an opening. Typically, the user is able to place a substance into the cavity via an aperture that is defined by the wall. The aperture may be covered by a lid 104, so that once the substance has been located in the cavity, the cavity can be closed. The lid may, for example, be a removable lid, or the lid may be attached to the wall via a hinge.

[0109] Typically, the heating device 100 comprises a spout 106, where the substance may be poured out of this spout once it has been heated. The spout may comprise a sieve or a filter. This is particularly beneficial where the heating device is used to brew a beverage such as chai, since the filter may be used to trap spices so that the spices are not transferred to a cup into which the chai is being poured. The filter may be retractable or removable to provide versatility.

[0110] The heating device 100 comprises a heating element 108 that is arranged to heat a substance located in the cavity of the heating device. The heating element may comprise a coil or a wire and may be located at the base of the heating device. Equally, the heating element may be located on the wall. Equally, the heating element may comprise a plurality of constituent heating elements, where these heating elements may be distributed about the heating device so as to ensure a consistent temperature throughout the substance as the substance is heated. It will be appreciated that various types and placements of heating element may be used.

[0111] The heating element 108 may be removable, where this can simplify the cleaning of the heating device 100 and / or of the heating element. For example, the heating element may be located in a removable tray that is located at the base of the heating device. Equally, the heating element may comprise a probe that can be inserted into the cavity from the top of the heating device (and, e.g., secured to the lid of the heating device).

[0112] Using a removable heating element further provides the option of retrofitting the heating element to an existing heating device. For example, by inserting a removable heating device into a conventional kettle, a user may be able to benefit from certain aspects of the disclosures herein while still using their existing products.

[0113] The present disclosure relates at least in part to a sensor (termed herein as a ‘multiphase level sensor’) 200 that can be used to determine a level of a substance that is located in the heating device. More specifically, the multiphase level sensor is arranged to determine the levels of a plurality of component substances of the substance located in the heating device, which component substances may be at different phases. In this regard, before operation of the heating element 108, the substance in the cavity typically comprises a fluid (e.g. a liquid), but the heating device may equally be used to heat solids. As the substance is heated, the composition of the substance changes so that the substance comprises a plurality of component substances (e.g. both of a liquid and a froth).

[0114] The ’level’ of the substance typically comprises a height of the substance in the heating device 100, where this height may be defined in terms of a total liquid volume. For example, if there is 1500ml of liquid in the heating device and a further 300ml of froth, the level of the liquid is typically 1500ml and the level of the froth is typically 1800ml (since the froth typically floats on top of the liquid). The multiphase level sensor 200 is arranged to determine a level of one or more components of the substance, where these components are different and are at different phases, states, or densities. With the example of chai, which will be expanded on below, the substance typically comprises a liquid (a mix of water / milk / spices) as well as a froth that floats on top of this liquid. The multiphase level sensor is arranged to determine the level of each of the liquid and the froth. It will be appreciated that the multiphase level sensor may equally be used to determine the levels of two components of the same phase where these components are separated (e.g. a water and an oil).

[0115] As used herein, the ‘phase’ or the ‘type’ of a substance preferably connotes a form of the substance, the form being, for example, solid, liquid, gas, froth, foam, slush, etc. The phase of a substance may relate to a fundamental phase of that substance but may equal relate to a substance (or a component substance) comprising different phases of material (e.g. a foam is typically a mixture of a fluid and a gas). For the purposes of the multiphase level sensor, a component substance that comprises a foam is considered to be in a different phase than a component substance that comprises a liquid or a component substance that comprises a gas. Typically, component substances at different phases are separated based on the different densities of these component substances where, for example, typically a foam is less dense than a liquid so typically a foam will float on top of a liquid.

[0116] Typically, the heating device 100 is arranged so that the heating element 108 is operated in dependence on the multiphase level sensor 200. In particular, the heating element may be operated in dependence on one or more of: an amount of liquid that is present in the cavity; an amount of froth that is present in the cavity; and / or a ratio between the amounts of liquid and froth present in the cavity.

[0117] One potential use of the heating device 100 is to brew chai (or chai tea) - and the heating device may be a chai maker. Chai is a popular drink in numerous countries. Conventionally, chai is brewed by boiling water in a saucepan, adding tea and spices to the water, bringing the water to the boil, adding milk to the water, and then bringing this mixture back to the boil. The heating of the milk can produce a substantial amount of froth.

[0118] This froth contributes to the taste of the chai and so some froth is often desirable; however, if the chai mixture is heated too strongly, there can be an overproduction of froth that results in the mixture overflowing the saucepan and leaving a sticky mess that is difficult to clean. Therefore, conventional methods of brewing chai require continual oversight and precise control of the brewing process. It will be appreciated that there are numerous methods of making chai (e.g. using different spices, or combining the components of the chai in a different order).

[0119] With the heating device 100 of the present disclosure, it is possible to control the heating of the chai mixture based on the level of froth being produces (as detected by the multiphase level sensor) so as to produce chai that has a desired level of froth but that does not risk overflowing the heating device.

[0120] More generally, the heating device may be a beverage maker, where the heating device may be used to brew numerous types of beverages (e.g. coffee, smoothies, etc.). Yet more generally, the heating device may be a kitchen appliance, a cooking appliance, a food processor, and / or a culinary appliance. In this regard, the heating device may be used to heat foods such as soup, butter, or chocolate. In each of these instances, the multiphase level sensor may be useful to determine a progress of heating of the foods (e.g. to determine an extend to which a stick of butter has melted).

[0121] As described above, the heating device 100 is typically arranged to operate in dependence on a multiphase level sensor. In general, the multiphase level sensor 200 is arranged to determine the level (or quantity) of two or more component substances (typically two or more fluids) of a substance located in the cavity. The multiphase level sensor may also be arranged to determine properties of the component substances (e.g. a temperature, density, pressure, etc. of the component substances. Therefore, for example, the multiphase level sensor may be arranged to determine relative quantities of liquid and of froth that are present in the heating device.

[0122] Various types of sensor may be used for the multiphase level sensor 200. For example:

[0123] The multiphase level sensor may comprise one or more mechanical floats, which mechanical floats may have differing densities so that they float on different substances. For example, the multiphase level sensor may comprise a first float that is arranged to float on a liquid but to sink beneath a froth (or a foam) and the sensor may comprise a second float that is arranged to float on a froth. The combination of floats then provides an output that indicates the level of both a liquid and a froth in the cavity.

[0124] For example, the first float may have a density of greater than 500kg / m3and / or less than 900kg / m3(so as to float on most liquids but not on most froths) and the second float may have a density of less than 20kg / m3and greater than 3kg / m3(so as to float on most froths but not on most gases). Various densities of float may be suitable for various intended uses and / or for various substances that may be present in the cavity.

[0125] The level of each component substance may be detected based on one or more floats moving past a switch on the wall 102 of the heating device. Such an embodiment provides a discrete measurement of the levels that may be used to indicate when a component has passed a threshold (e.g. is close to overtopping the wall). Equally, the float may be arranged to move along a groove in the wall so that the float provides a continuous measurement. Similarly, the float may be connected with a potentiometer, where the amount of resistance provided by the potentiometer then depends on the level of the float (e.g. the potentiometer may be linked to a fixed resistor to form a potential divider so that an output current is dependent on the potentiometer resistance and thus the float level).

[0126] The multiphase level sensor may comprise one or more optical sensors (e.g. a camera or an infrared sensor). Typically, this involves the sensor comprising one or more transmitter and receiver pairs located on opposing sides of the cavity, where a component substance between the transmitter / receiver pair can be identified based on a reading at the receiver (e.g. foam typically blocks more light than air, and liquid typically blocks more light than foam).

[0127] Equally, a single transmitter / receiver pair (or a plurality of transmitters / receivers) may be provided. For example, a transmitter / receiver pair may be arranged on the interior of the lid of the heating device, where the receiver is arranged to measure an amount of light that is reflected by a substance in the cavity. A level and a type of the component substances in the heating device can then be determined based on an amount of light reflected from these substances.

[0128] Furthermore, a single transmitter may be combined with a plurality of receivers at specific locations. Since different substances (e.g. liquids and foams) have different refractive indexes, by arranging the receivers at various locations and detecting the amount of light detected by the various receivers it is possible to identify the refractive index of the component substances in the cavity and thus to determine a type / phase / level of these component substances.

[0129] In some embodiments, image recognition (e.g. using neural networks or artificial intelligence) is used to determine the level of various component substances in the heating device.

[0130] The multiphase level sensor may comprise an acoustic sensor. Similar to the optical sensor, an acoustic transmitter may be arranged to transmit a sonic or ultrasonic signal to the cavity. A signal received at a corresponding acoustic receiver, or at one or more of a plurality of acoustic receivers, can then be used to determine the type and level of the component substances in the cavity.

[0131] The multiphase level sensor may comprise a temperature sensor and / or an array of temperature sensors. The type and level of the substance in the cavity can then be determined based on the temperatures at various locations in the cavity as well as the changes in these temperatures over time. For example, the component substance by each temperature sensor may be determined by these changes since liquid typically conducts heat more quickly than froth, which in turn conducts heat more quickly than air - and the presence of a step change in temperature between a pair of temperature sensors will typically indicate an interface between component substances of different phase.

[0132] The multiphase level sensor may comprise an array of density sensors or an array of pressure sensors, where the phase or type of the component substances can be determined based on their density or pressure.

[0133] The multiphase level sensor may comprise a conductive arrangement in which a first, driving, contact is arranged to provide an electrical signal to the substance in the cavity and a second, receiving, contact is arranged to receive the electrical signal. The nature and magnitude of the signal received at the second contact provides an indication of the types and levels of the component substances in the cavity (since different types / phases of substance have different resistances).

[0134] Such an embodiment of a multiphase level sensor is described in more detail below with reference to Figures 1 b and 2.

[0135] Specifically, referring to Figures 1 b and 2, there is shown an embodiment of the multiphase level sensor 200 that comprises a first, driving, probe 202 and a second, receiving, probe 204.

[0136] Each probe 202, 204 comprises a conductive probe that is exposed to the cavity of the heating device (e.g. the probes may extend from the base or the top of the heating device or from the wall 102 of the heating device, or the probes may be recessed into the wall of the heating device). The probes are arranged to extend parallel to the wall of the heating device so that an amount of the probes that is in contact with a substance in the cavity depends on the volume of that substance. Typically the probes are arranged to extend along a substantial portion (e.g. greater than 50%) of the height of the cavity and / or to extend along the entirety of the height of the cavity.

[0137] The probes 202, 204 provide a cathode and anode pair, where in use, the driving probe 202 is arranged to provide an electric current, which current is then received by the receiving probe 204. The magnitude of current detected by the receiving probe depends on both the amount of material present in the cavity and the type of material present, e.g. a liquid and a froth will provide different amounts of resistance. This amount of resistance, and the nature of the material in the cavity, can then be determined by the amount of current detected by the receiving probe 204.

[0138] While Figure 1 b shows the driving probe 202 and the receiving probe 204 as being separate probes that extend into the cavity from the lid of the heating device 100, it will be appreciated that various other arrangements are possible. For example, the driving probe and the receiving probe may be located on a shared structure, where these probes are electrically isolated by an intermediate material of the probe. Equally, the probes may extend from the base of the cavity and / or the probes may be recessed into a wall of the cavity. Typically, separate probes are used to avoid any surface tracking effects or erroneous conductions between the probes.

[0139] The probes 202, 204 may be an integrated component of the heating device 100 (e.g. a part of the wall 102 of the heating device). Equally, the probes may be a removable component. This enables the probes to be removed from the heating device for cleaning. Furthermore, this enables the probes to be retrofitted to an existing heating device (e.g. to increase the functionality of this existing heating device).

[0140] Such an arrangement provides a multiphase level sensorthat can be cleaned easily (since the driving probe 202 and the receiving probe 204 can be wiped clean in a straightforward manner. Furthermore, this arrangement provides versatility, since the probes can be biased at different impedance levels to provide a wide range of sensitivity.

[0141] In some embodiments, a separate pair of probes is used for the detection of different component substances (e.g. foams versus liquids). In some embodiments, separate impedance and / or amplification channels are used to switch between sensing different component substances on a single pair of probes.

[0142] The driving probe 202 and / or the receiving probe 204 typically comprise a continuous, or effectively continuous, array of exposed contact points. Equally, the driving probe and / or the receiving probe may comprise a smaller number of spaced contact points. The contacts may be connected. Equally, the probes may comprise separated sets of contacts.

[0143] Typically, the driving probe and / or the receiving probe 204 comprises a plurality of separated contact points (e.g. separated by fixed resistors) that may each be associated with a different output. This enables the resistance of different layers of the substance to be determined (as opposed to determining a single resistance of the substance as a whole). Therefore, the phases / types of the component substances at these layers can be better determined. Referring to Figure 3, there are shown various components associated with the multiphase level sensor 200 of Figure 2.

[0144] The multiphase level sensor 200, or more specifically each of the driving probe 202 and the receiving probe 204, comprises a plurality of exposed electrical contacts. The driving probe is arranged to transfer a current, typically an alternating current (AC), to a substance in the cavity, and the receiving probe is arranged to receive this current via the substance. The resistance of the substance, and thus the level and the type (e.g. the phase or state) of the component substances in the cavity can then be determined based on the current received by the receiving probe. The use of an alternating current (AC) waveform reduces the build-up of ions / corrosion deposits as compared to a direct current (DC) waveform.

[0145] In various embodiments, the resistance (or impedance) of the component substances in the cavity is determined based on one or more of: a waveform received by the receiving probe, a magnitude of the waveform; a phase shift of a waveform (between the driving probe and the receiving probe), a current received by the receiving probe, and a voltage drop associated with the substance.

[0146] The contacts of each probe are typically connected (so that a control unit of the multiphase level sensor receives a single current reading from the receiving probe). In some embodiments, the multiphase level sensor comprises one or more separated probes, e.g. a first electrical contact of the receiving probe comprises may comprise a dry protect contact 212 and / or a final electrical contact of the receiving probe may comprise an overflow protection contact 218.

[0147] If the dry protect contact 212 indicates that there is no liquid or froth present at the level of this first contact (e.g. if the dry protect contact detects less than a threshold current), then the multiphase level sensor 200 can indicate that the heating device 100 is empty and so the heating element 108 should not be turned on.

[0148] Similarly, if the overflow protection contact 218 indicates that this last contact is surrounded by a liquid or a froth (e.g. if the overflow protection contact detects greater than a threshold current) it can be determined that the substance in the cavity is close to overflowing the wall 102 of the heating device. This determination can be used to reduce the heating being applied to the substance to prevent such overflowing.

[0149] Each of the driving probe 202 and the receiving probe 204 comprises an array of electrical contacts, which electrical contacts are typically separated by fixed resistors. This array of contacts extends along the height of the cavity so that the amount of electricity passing between the contacts on the driving probe 202 and the receiving probe 204 provides an indication of the component substances present at a plurality of different heights in the cavity. More specifically, any variance in the component substances present in the cavity will lead to a corresponding change in the (overall) resistance of the substance, which change can be detected by an interrogation of the current being received by the receiving probe.

[0150] The multiphase level sensor 200 is arranged to communicate with an impedance measurement system 222 that determines an amount of resistance associated with the substance in the cavity. This impedance measurement system 222 feeds into a control unit 224, which control unit is able to determine the component substances, and the levels of these component substances based on the determined resistance. For example, a high resistance typically indicates that a large amount of air is present in the cavity; a lower resistance typically indicates that some froth is present; and an even lower resistance typically indicates that a lot of froth is present. The control unit may be preprogrammed, or may be subject to a calibration process, in orderto identify the resistances associated with various types of substance (and this programming / calibration may depend on an expected use of the heating device).

[0151] The control unit 224 is typically arranged to operate with a user interface 226 in order to receive instructions from a user. These instructions may relate to a desired use of the heating device 100. The instructions may comprise a binary on / off instruction (where the user interface may comprise a switch); equally, the instructions may comprise more detailed instructions about a desired output (e.g. to indicate whether the heating device is being used to make chai or to make soup), a desired amount of an output, or specific brewing properties (e.g. a desired completion time, additives that might be added to the cavity, etc.).

[0152] The control unit 224 is arranged to receive the inputs from the impedance measurement system 222 and the user interface 226 and to provide an input to a power controller 230 that controls the heating element 108 in orderto achieve the desired output. For example, where the user wishes to brew chai, the control unit is able to heat a substance in the cavity to provide froth, and to then control the heating of the substance (based on the multiphase level sensor 200) to avoid an overproduction of froth that leads to a spillage. In this way, the heating element can be controlled in dependence on user instructions and also in dependence on the conditions inside the cavity of the heating device 100.

[0153] The control unit 224 may also consider one or more further properties of the component substances in the cavity. For example, the control unit may receive a temperature input from one or more temperature sensor 230 that is located in the cavity. Any temperature readings may be used in conjunction with the multiphase level sensor (where the readings from the multiphase level sensor may also be used to determine a component substance that is surrounding a given temperature sensor). The temperature sensor and / or another sensor may be integrated into the multiphase level sensor (e.g. located on a probe of the multiphase level sensor).

[0154] In some embodiments, the multiphase level sensor is arranged to alternate the operation of the driving probe 402 and the receiving probe 404. That is, during a first period of time the first probe is used as the driving probe and the second probe is used as the receiving probe, and during a second period of time the second probe is used as the driving probe and the first probe 404 is used as the receiving probe. This alternating of the probes can reduce the wear that is experienced by a single probe.

[0155] Referring to Figure 3, there is shown an illustration of how the resistance detected by the multiphase level sensor 200 may change over time as a substance is heated by the heating device 100.

[0156] As shown in Figure 3, at a first time, the heating device 100 is empty and the multiphase level sensor 200 identifies a high resistance since the receiving probe 204 is surrounded by air. Over a first period of time, the heating device is partially filled with a liquid and the resistance level drops. Over a second period, the liquid in the cavity is heated and this results in the production of froth. The resistance detected by the multiphase level sensor decreases as the amount of froth increases.

[0157] In this regard, the multiphase level sensor 200 and the control unit 224 may determine the types and levels of the component substances based on absolute readings (e.g. where the control unit may comprise a table that relates resistances to various mixes of substances). Equally, the multiphase level sensor and the control unit may determine the types and levels of the component substances based on a determined change in resistance. A large rate of change of resistance typically indicates that a substance is being introduced into the cavity - and this may be confirmed by the temperature sensor 230 indicating the temperature in the cavity is low. A slower rate of change of resistance may then indicate that a froth is being produced within the cavity itself (and a rate of production of froth, and thus a level of the froth, may be determined based on this rate of change of resistance).

[0158] Referring to Figure 4, the heating device 100 typically comprises a computer device 1000, which computer device is arranged to control the heating device and / or to provide information relating to the operation of the heating device. For example, the control unit may comprise a computer device and / or may be a part of a computer device that forms the heating device.

[0159] The computer device 1000 typically comprises a processor in the form of a processor 1002, a communication interface 1004, a user interface 1006, a memory 1008, an operative element 1010, and a sensor 1012. These components are coupled to one another by a bus 1014.

[0160] The processor 1002 executes instructions, including instructions stored in the memory 1008, in a storage of the computer device 1000, and / or in a removable storage of the computer device.

[0161] The communication interface 1004 enables the computer device 1000 to communicate with a further computer device, e.g. to receive instructions from the further computer device or to transmit information to the further user device. The communication interface may comprise a wired communication interface or a wireless communication interface and may, for example, enable communication via one or more of: a local area network, a wide area network, the Internet, Bluetooth®, Infrared, a universal serial bus (USB) interface, or any other type of communication medium.

[0162] The user interface 1006 enables a user to interact physically with the heating device 100. The user interface may comprise one or more buttons (e.g. where operating a button operates the heating element 108). Equally, the user interface may comprise a touchscreen or a timer input.

[0163] It will be appreciated that the heating device 100 may comprise only one type of user interface. Typically, the heating device comprises both of the communication interface 1004 and the user interface 1006 so that a user can interact with the heating device directly via the user interface and indirectly (using a further computer device) via the communication interface.

[0164] The memory 1008 stores instructions and other information for use by the processor 1002. The memory typically comprises one or more of: Random Access Memory (RAM); and Read Only Memory (ROM).

[0165] The operative element 1010 typically comprises the heating element 108. Alternatively (or additionally) the operative element may comprise one or more of: a stirring element, an agitation element, a placing element (e.g. that places material into the cavity), a removal element (e.g. that removes material from the cavity), and a filtering element. It will be appreciated that further types of operative element may be provided, where these operative elements may be provided in dependence on an intended use of the heating device.

[0166] The sensor 1012 typically comprises the multiphase level sensor 200. Alternatively (or additionally) the sensor may comprise one or more of a temperature sensor, a PH sensor, a pressure sensor, a density sensor, or any other sensing device.

[0167] A computer program product is provided that includes instructions for carrying out aspects of the method(s) described below. The computer program product may be stored, at different stages, on one or more of: the memory 1006; a storage of the computer device 1000; a removable storage (e.g. a USB drive); and another computer device. The storage of the computer program product is non- transitory, except when instructions included in the computer program product are being executed by the processor 1002, in which case the instructions are sometimes stored temporarily in the processor or memory. The computer program product may be stored on a removable storage device that is removable from the computer device, such that the computer program product may be held separately from the computer device from time to time. Different computer program products, or different aspects of a single overall computer program product, may be present on a plurality of computer devices used by different components of the heating device or different users of the heating device.

[0168] Referring to Figure 5, there is described a method of operating the heating device 100 in dependence on the multiphase level sensor 200. The method is typically performed by a computer device 1000 associated with the heating device (e.g. by the control unit 224).

[0169] In a first step 11 , the computer device 1000 receives a user input, e.g. via the user interface 226, 1006 and / or via the communication interface 1004. The user input typically indicates a desired operation of the heating device and / or a desired heating characteristic.

[0170] In a second step 12, the computer device 1000 receives a reading from the multiphase level sensor 200. The computer device determines a level and type of the component substances in the cavity based on this reading. Typically, at this stage the cavity is partially filled with a liquid.

[0171] In a third step 13, the computer device 1000 provides a signal to the heating element 108. The signal depends on the user input and on the reading from the multiphase level sensor. For example, different beverages typically require different speeds of heating; chai is typically brewed over an extended period of time at a fairly low temperature, whereas coffee is typically brewed more quickly at a higher temperature.

[0172] In a fourth step 14, the computer device 1000 receives another reading from the multiphase level sensor 200. The computer device again determines a level and type of the component substances in the cavity based on this reading. The level and the nature of the component substances within the cavity typically changes during the brewing process. For example, where the heating device is used to make chai, the heating of milk in the cavity results in the production of froth. The reading from the multiphase level sensor enables the computer device to determine a level of this froth as well as a level of the liquid beneath the froth. In a fifth step 15, the computer device 1000 provides an updated signal to the heating element 108. This updated signal may, for example, be used to reduce the amount of heat being provided to the cavity if the reading from the multiphase level sensor 200 indicates that froth is close to overflowing the wall 102 of the heating device. Equally, the updated signal may, for example, be used to increase the amount of heat being provided to the cavity if the substance in the cavity is detected to not be at a suitable temperature.

[0173] The further step 14 and the fifth step 15 may be repeated throughout a brewing process to control the operation of the heating element 108 in dependence on the conditions in the cavity. This may continue until the brewing process is complete, e.g. until the heating device reaches a finishing condition or until a user ends the brewing process.

[0174] As well as being operated in dependence on the multiphase level sensor 200, the computer device 1000 may control the heating element 108 in dependence on various other factors. For example, the computer device may control the heating element in dependence on: a temperature in the cavity, a pressure in the cavity, a density in the cavity, and / or one or more additives that have been placed into the cavity (e.g. spices that may be added to chai). Such factors may be determined using one or more sensors, e.g. temperature or pressure sensors, which sensors may be combined with the multiphase level sensor or may be provided separately.

[0175] Typically, the computer device is arranged to operate, and / or the heating element 108 is arranged to operate, in dependence on one or more of:

[0176] A level of a substance present in the cavity. In particular, as described above, the heating element 108 may be controlled so as to reduce the amount of heating provided by the heating element when a threshold level of a component substance (e.g. froth) is detected in the cavity.

[0177] A minimum level of a substance present in the cavity. In particular, the multiphase level sensor may be able to determine when the heating device is near empty so that the heating element is exposed to air. Typically, the computer device 1000 is arranged to prevent operation of the heating element 108 in this situation.

[0178] An input and / or determined heating time. For chai in particular, it is desirable to heat the substance for a prolonged period of time (at a fairly low heat). Therefore, the heating element 108 may be arranged to provide such a low heat over a prolonged period of time. The heating time may be input by a user. Equally, the heating time may be determined based on the substance (e.g. based on an amount of tea being heated).

[0179] A desired finish time. A user may wish to instruct the heating device to finish a heating process at a certain time, e.g. so that chai is ready and waiting for the user when they wake up in the morning or when they arrive home from work. The computer device 1000 may then be arranged to control the heating element to brew the chai over a preceding period of time and to then maintain the chai at a certain temperature so that it is ready for consumption at the instructed time. In some embodiments, the heating device 100 comprises one or more compartments that are linked to the cavity, where substances in these compartments can be introduced into the cavity. This enables the heating device to accurately provide various outputs (e.g. various beverages or foods). For example, the heating device may comprise a water container, where this water container is arranged to provide a certain amount of water to the cavity prior to the operation of the heating element 108. The water container may be filled completely and then a portion of the water in this container may be provided to the cavity in dependence on the user input (e.g. in dependence on whether a user wishes to brew one cup of chai or two cups of chai). This enables the precise provision of a suitable amount of a substance to the cavity.

[0180] The heating device 100 may comprise other compartments, for example the heating device may comprise: one or more compartments for spices; a compartment for milk; and / or an output compartment for holding a heated substance. The output compartment may be connected to the cavity via a filter.

[0181] Furthermore, in various embodiments, the heating device 100 may be arranged to automatically perform various other steps to provide efficient brewing of various substances. For example, where the heating device is used to brew chai, the heating device may be arranged to first add water to the cavity, to then add (chosen) spices to the cavity, to bring this water to the boil, to then add milk to the cavity, and to then control the heating element so as to control an amount of froth produced by the milk. This enables the heating device to brew chai with a desired order of operations with minimal user input.

[0182] The addition of one or more substances to the cavity, or the removal of one or more substances from the cavity, may occur in dependence on the multiphase level sensor 200. For example, the computer device 1000 may be arranged to add a substance to the cavity when it detects a threshold amount of froth in the cavity.

[0183] In some embodiments, the computer device 1000 is arranged to determine a temperature of a substance in the cavity and / or to determine whether a substance (e.g. a fluid) in the cavity is boiling. The computer device may then add a further substance to the cavity in dependence on the substance being boiling or near boiling. In particular, where the heating device is being used to make chai, it may be desired to begin by boiling water and then to add the spices and / or the milk only when the water is already boiling or is near boiling.

[0184] Various other substances may be heated by the heating device 100, where a desired output may be selected by a user so as to provide a versatile heating device.

[0185] The heating device 100 may be arranged to receive one or more capsules (e.g. containing spices, containing a chai mix, or containing another substance) so as to prepare a desired beverage. In particular, the heating device may comprise a compartment for receiving a capsule and a mechanism for transferring the contents of the capsule to the cavity. The present disclosure further extends to such a capsule for use with the heating device.

[0186] In some embodiments, the heating device 100 comprises an agitator and / or a stirrer that is arranged to mix or to stir a substance in the cavity. This agitator may be controlled based on the multiphase level sensor 200, e.g. to mix froth into the liquid as it is produced, and may be controlled based on the substance being heated. The agitator may comprise a structure, e.g. a rod, that extends into the cavity and moves through the cavity to mix the substance. For example, the agitator may move in an ellipse about a central axis of the cavity (where the multiphase level sensor may extend along this central axis). Equally, the agitator may comprise a jet that is arranged to push high pressure air through the substance in order to mix the substance. It will be appreciated that various agitating devices may be used with the heating device.

[0187] Where the heating device 100 is used to heat a liquid, the bubbles formed as the liquid approaches a boiling point have a secondary effect of providing mixing. Typically, as the liquid approaches the boiling point, the computer device 1000 controls the heating element 108 so as to reduce the heating (to avoid the overflowing of froth or to avoid overheating the substance), whereby diffusion driven by temperature still causes the mixing of the substance but the production of bubbles reduces. The agitator may be arranged to mix the substance at this point, following the provision of a signal that reduces the power provided by the heating element.

[0188] With such an embodiment, mixing can be provided by the agitator to replace mixing that would otherwise come from the boiling of a liquid. Therefore, the heating device 100 can heat the substance to a lower temperature without sacrificing mixing. This enables the production of an output (e.g. chai) without providing heating to an extent that would cause substantial frothing. This embodiment of the heating device (and indeed other embodiments of the heating device) may then be provided without the multiphase level sensor, since the amount of froth produced is low by virtue of the temperature being kept beneath that temperature that would cause substantial frothing (e.g. beneath a boiling point of a fluid in the cavity).

[0189] The agitator may also be used to break up any bubbles present in the cavity, where this may enable the reduction of any froth that is produced. Not least due to this, the agitator may be operated in dependence on the multiphase level sensor, e.g. the agitator may be activated when a threshold level of froth is detected in the cavity and / or when a level of froth in the heating device approaches an upper limit.

[0190] The agitator may be removable. The agitator may interfere with the brewing of certain substances. For example, where chai is brewed using a bag of spices, the agitator may damage this bag (or be damaged by this bag). Therefore, the agitator may be removable or may be controllable by the user interface so that it can be set to not operate during certain brewing processes.

[0191] The temperature of the substance in the cavity, and the type of the component substances present in the cavity, may be inferred based on the power consumption of the heating element 108 and more specifically based on dT / dP (the change in temperature caused by providing a unit of power to the heating element). In this regard, the amount of power needed to cause a unit change in the temperature of a substance in the cavity increases as the temperature of this substance increases. Therefore, the heating device may be arranged to maintain a temperature of the substance (e.g. a temperature just below a boiling temperature) based solely on an evaluation of the power being provided to the heating element. Such a method enables the control of the heating development without the need for componentry to be inserted into the cavity. Using this method alongside an agitator, that may be inserted into the cavity, enables the brewing of beverages at below boiling point where the mixing that would normally be a side effect of the boiling is substituted with mixing from the agitator. It will be appreciated that this method of temperature inference may be used with or without any of the other features disclosed herein (e.g. this method could be used in an otherwise conventional heating device).

[0192] In some embodiments, the heating device 100 comprises a cleaning mechanism. For example, the heating may be arranged to receive water and cleaning fluid, to heat the water, and to operate the agitator so as to clean the heating device and / or the multiphase level sensor. Equally, the heating device may comprise a dedicated cleaning mechanism, such as a cleaning jet and / or an automated sponge.

[0193] The heating device 100 may then be arranged to clean itself automatically following the preparation of a beverage or a foodstuff.

[0194] As well as being used to receive instructions, the user interface may be arranged to provide information to a user. For example, to indicate how many cups of chai may be brewed based on the amount of a substance in the cavity and / or in a compartment of the heating device 100, or to provide information on the progress of a heating or brewing process, e.g. to indicate to a user that a beverage is ready.

[0195] The multiphase level sensor 200 is typically integrated into the lid 104 of the heating device 100, as shown in Figures 1 a and 1 b. The lid may be removable and / or detachable from the remainder of the heating device in order to enable access to the cavity and also to enable access to the multiphase level sensor so that this sensor can be more easily cleaned. Where further componentry, such as the agitator, is provided, this further componentry may equally be integrated with the lid.

[0196] There may be provided a lid that comprises each of the multiphase level sensor 200 and a heating element. Such an embodiment enables the lid to be retrofitted to an existing heating device, where a substance can then be heated by operating the heating element on the lid in dependence on the multiphase level sensor. This precludes the need to modify any componentry of this existing heating element (other than changing the lid).

[0197] Referring to Figures 6a, 6b, 6c, and 6d, there are shown embodiments of a heating device that comprises a perforated chamber (e.g. a spice basket). This perforated chamber may be provided as a component of the heating device. Equally, this perforated chamber may be provided separately to (e.g. without) the heating device. For example, the heating device and the perforated chamber may be provided as a kit of parts - and this kit of parts may comprise a plurality of perforated chambers. Equally, the perforated chamber may be provided as a component that can be retrofitted to an existing heating device (e.g. the perforated chamber may be provided as a part of a lid that can be used with an existing heating device).

[0198] The perforated chamber 300 may be used with the components described above, e.g. the perforated chamber may be used in combination with the multiphase level sensor 200. Equally, the perforated chamber may be provided in isolation (e.g. the perforated chamber may be used with a conventional heating device such as a conventional kettle, which conventional kettle may not have a multiphase level sensor).

[0199] The perforated chamber 300 is arranged to be mounted within (e.g. the cavity of) the heating device 100, where typically this involves the perforated chamber comprising a mounting structure (e.g. a thread, a ledge, or a pin).

[0200] The perforated chamber comprises an aperture 302 (e.g. a closeable aperture, such as a lid) so as to enable material to be placed within the perforated chamber. Typically, the aperture is a large aperture so that a user is able to insert a stirring device into the perforated chamber to stir a material within this chamber. This enables a user to place a substance, e.g. a mix of spices, into the perforated chamber in order to brew a beverage using this substance.

[0201] In order to mount the perforated chamber 300 within the heating device 100, the perforated chamber typically comprises a threaded handle 304, which handle has a thread that is arranged to interact with a corresponding thread of the heating device. It will be appreciated that numerous other ways of mounting the perforated chamber within the heating device are possible; for example, in some embodiments, a protruding portion of the perforated chamber may rest on a corresponding ledge of the heating device.

[0202] The perforated chamber 300 may be provided as an integral part of the heating device 100. However, typically, and as shown in Figures 6c and 6d, the perforated chamber is typically removable from the heating device. In particular a user may be able to disengage the threaded handle from the heating device and then remove the perforated chamber from the heating device, where this enables material (e.g. spices) to be inserted into or removed from the perforated chamber.

[0203] Referring to Figure 7a, in some embodiments, the perforated chamber 300 is arranged to be mounted in the heating device 100 in such a way that there is a gap between the perforated chamber and the base of the heating device.

[0204] However, as shown in Figure 7b, typically the perforated chamber 300 is arranged to contact the heating device 100 and / or to contact a heating element 108 of the heating device. By providing a thermal interface 308 between the perforated chamber and a surface of the heating device (the surface being associated with the heating element), it can be ensured that there is boiling within the perforated chamber.

[0205] In this regard, the size of the perforations (or apertures) of the perforated chamber 300 is typically selected so as to allow the flow of fluids through the walls of the perforated chamber, but to prevent the flow of solids through these walls. Therefore, a substance, such as a mixture of spices, may be placed into the perforated chamber. The perforated chamber may then be inserted into the heating device 100 such that a fluid (e.g. water) in the heating device enters the perforated chamber, and a drink, such as chai, may then be made by heating the fluid. In an example embodiment, the perforated chamber comprises a mesh (e.g. a stainless or nickel mesh) with a perforation size (e.g. a perforation height, width, and / or diameter) that is in the range of 0.02mm to 0.5mm; such an embodiment enables the chamber to hold fine spices granules whilst allowing for the diffusion of water into the chamber. In some embodiments, the apertures of the perforated chamber are sized such that water is able to pass through these apertures, but milk is unable to pass through these apertures.

[0206] To ensure that the fluid that has entered the perforated chamber 300 is at a desired heat (e.g. that this fluid is boiling) it can be beneficial to ensure that there is a thermal interface 308 (e.g. a solid thermal interface) between the perforated chamber and the heating device 100. In this regard, the arrangement of Figure 7a can result in localized boiling between the lower surface of the heating device and the perforated chamber, where the boiling fluid in this area is unable to enter the perforated chamber due to the surface tension of the bubbles in the boiling fluid. Therefore, this arrangement can cause inefficient heating of the substance in the perforated chamber.

[0207] In contrast, the arrangement of Figure 7b ensures that the fluid in the perforated chamber 300 is heated by the heating element 108 of the heating device. This ensures, for example, that boiling occurs within the perforated chamber so that a desired beverage can be brewed quickly, efficiently, and effectively. In practice, this may result in a first portion of a fluid boiling outside of the perforated chamber and a second portion of the fluid liquid boiling inside the perforated chamber (with each portion of the fluid being unable to pass through the perforations). After the operation of the heating element ends (and before this operation starts), the liquid is not boiling and so is able to pass between the perforations of the perforated chamber. Therefore, once a brewing process is complete, the liquid within the perforated chamber cools down so as to no longer be boiling, flows through the apertures of the perforated chamber, and can then be poured from the spout 106 of the heating device.

[0208] The control unit of the heating device 100 may be arranged to determine whether boiling is occurring within the perforated chamber (and to operate the heating element 108 to cause a desired amount of boiling while ensuring there is no overtopping of the perforated chamber). Determining this boiling may, for example be based on a determination of a change in the temperature of a substance in the heating device or in the perforated chamber 300 that occurs when a unit input of power is provided to the heating element (e.g. dT / dP).

[0209] Typically, the perforated chamber 300 is formed of steel, e.g. stainless steel.

[0210] The thermal interface 308 typically comprises a base section of the perforated chamber 300 where the thermal interface may be a surface that both forms a wall of the perforated chamber and also contacts (or conducts heat from) the heating element 108 of the heating device 100.

[0211] In some embodiments, the thermal interface 308 comprises a surface of high conductivity (e.g. a material or surface with a thermal conductivity of at least 40 W / mK) that is arranged to contact a corresponding surface of the heating device. Therefore, heat generated by the heating element 108 is able to rapidly heat the thermal interface and to heat the fluid within the perforated chamber. The thermal interface may, for example, comprise a copper surface or an aluminium surface. Typically, the thermal interface comprises a thin surface, and so the use of such highly conductive materials is not necessary (e.g. since a chamber made of steel or a similar material has a sufficient conductivity to cause boiling in the chamber).

[0212] In some embodiments, the thermal interface 308 may comprise perforations that enable a fluid in the perforated chamber 300 to contact (or approach) the heating element 108. Therefore, the fluid in the perforated chamber can be heated by the heating element (where the perforated chamber may or may not be substantially heated by the heating element). In other words, the thermal interface may enable the heating element 108 of the heating device 100 to heat a fluid in the perforated chamber with or without the thermal interface substantially conducting heat itself. It will be appreciated that the presence of these perforations is optional.

[0213] Referring to Figure 8, in some embodiments, the perforated chamber 300 comprises a sealing structure 310, such as an O-ring) that provides a seal between the perforated chamber and a surface of the heating device 100. The sealing structure can be used to ensure that fluid heated by the heating element 108 passes into the perforated chamber instead of passing around the sides of the perforated chamber.

[0214] Typically, the heating device 100 and the perforated chamber 300 are arranged so that the thermal interface 308 and / or the sealing structure 310 is arranged to be located adjacent to and / or in alignment with the heating element 108 of the heating device. In particular, the thermal interface and / or the sealing structure may be arranged to contact a first surface of the heating device, which first surface is heated by and / or adjacent to, the heating element of the heating device.

[0215] In some embodiments, the perforated chamber 300 and / or the thermal interface 308 and / or the sealing structure 310 comprises a biasing structure (such as a spring or a magnet), which biasing structure is arranged to urge the thermal interface / sealing structure into contact with the surface of the heating device 100. In some embodiments, the operation of the threaded handle 304, and the process of mounting the perforated chamber within the heating device is arranged to press the thermal interface / the sealing structure into the surface of the heating device so as to ensure a tight fit between these components.

[0216] In some embodiments, the perforated chamber 300 is suspended from the base of the heating device so that the perforated chamber is not in physical contact with the thermal interface 308 (though heat may still transfer from the heating device to the perforated chamber via radiation and convection or conduction that occurs via a substance in the cavity).

[0217] Referring to Figures 9a and 9b, the heating device 100 may be compatible with a plurality of different perforated chambers 300, 400, which perforated chambers may be of different shapes, sizes, or materials. These different perforated chambers may be provided within a kit of parts or may be provided separately.

[0218] In particular, the different perforated chambers 300, 400 may comprise differently sized apertures or different thermal interfaces. This may comprise the different perforated chambers having different axial lengths (so that the different chambers can be inserted through a top lid of the heating device and these different chambers then extend different amounts into the heating device). Therefore, different chambers can be used for different purposes (e.g. for brewing, boiling, and / or steaming). In practice, different perforated chambers may be provided for: brewing chai, steaming vegetables, steaming rice, etc., where, for example, the chamber for steaming vegetables may have a greater aperture size than the chamber for brewing chai. Referring to Figures 10a, 10b, and 10c, there is shown another embodiment of a heating device comprising a perforated chamber.

[0219] In this embodiment, the heating device comprises an insulating wall 110, which insulating wall typically comprises polyurethane or vacuum insulation so as to prevent the loss of heat through the walls of the heating device. The heating device further comprises the spout 106 (e.g. with an integral strainer), the heating element 108, which heating element may comprise an electric or inductive heating element 114, and a heat transfer surface 112.

[0220] The perforated chamber 300 comprises an access cover 312 and a securing collar 314 that is arranged to interact with the heating device 100 so as to secure the perforated chamber in the heating device.

[0221] The heat transfer surface 112 of the heating device is arranged to interface with each of the heating element 108 and the perforated chamber 300. In particular, the perforated chamber may be arranged to protrude into a recess of the heat transfer surface 112 so that the heat transfer surface is arranged to provide a consistent and effective thermal connection between the heating element 108 and the (thermal interface 308 of the) perforated chamber. The heat transfer surface may comprise a conformal heat transfer surface or a ferrous surface. The recess may be sized so as to increase an amount of contact between the perforated basket and the heating device so as to improve the transfer of heat to the material within the perforated basket.

[0222] The inductive heating element 114 may be arranged to directly heat the perforated chamber 300 (e.g. while providing only a small amount of heating to the remainder of the heating device 100. Such a heating element can be used to efficiently heat the material within the perforated chamber. The heat transfer surface 112 may comprise a ferrous heat transfer that is arranged to be heated by the inductive heating element so as to transfer heat to the perforated chamber via the heat transfer surface.

[0223] In use, spices may be placed within the perforated chamber 300 before the perforated chamber is inserted into the heating device 108 along with a fluid such as water or milk. This fluid passes through the apertures of the perforated chamber so as to be present within the perforated chamber as well as being present in a cavity of the heating device 100 (where the perforated chamber is located within this chamber of the heating device). The fluid is then heated using the heating element 108. Due to the thermal interface, the fluid both within and outside of the perforated chamber is efficiently heated by the heating element and, e.g. begins to boil. This heating of the fluid causes the brewing of a beverage (or, for example, the steaming of vegetables). In the case of a beverage, the beverage can then be poured from the spout 106 of the heating device, where the beverage then passes from the interior of the perforated chamber through the apertures of the perforated chamber and through (e.g. a strainer in) the spout 106 of the heating device.

[0224] Where milk is used, this milk may be poured into the perforated chamber 300. As the milk heats it becomes unable to pass through the apertures of the perforated chamber so that any residue formed from the milk forms on the interior of the perforated chamber (instead of the walls of the heating device 100 as would occur if the perforated chamber were not used). The perforated chamber 300 ensures that any solid material placed into the perforated chamber remains within the perforated chamber. This ensures that a beverage produced using the perforated chamber does not have bits and also provides a more easily cleanable device.

[0225] In this regard, the perforated chamber 300 is typically removable from the heating device 100 so that, after use, the perforated chamber can be removed from the heating device and then cleaned.

[0226] In some embodiments, the perforated chamber 300 comprises an inner liner, which inner liner is removable from the remainder of the perforated chamber. The inner liner may comprise a mesh liner, e.g. the perforated chamber may comprise walls with apertures, where the fine mesh liner has smaller apertures than these apertures on the walls of the perforated chamber. Therefore, during use of the perforated chamber, material collects on the inner liner of the (removable) perforated chamber. Such an inner liner can be used to simplify the cleaning of the perforated chamber (e.g. the inner liner may be removed and cleaned following the use of the perforated chamber).

[0227] The inner liner may comprise a thermally conductive material so that heat can pass through the inner liner and into the material held in the perforated chamber. In some embodiments, the inner liner is arranged to transfer heat through a base of the perforated chamber to control the boiling that occurs in the perforated chamber.

[0228] In some embodiments, the heating device is waterproof and / or IP rated so as to enable the heating device to be cleaned using a dishwasher (e.g. without removing the perforated chamber).

[0229] Referring to Figures 11a and 11 b, there is shown an embodiment of a heating device that comprises a spiral heating element.

[0230] In a specific embodiment, the heating device comprises a logarithmic spiral element and / or a spiral element that is defined by the equations: xt= a * ebt* cosctyt= a * ebt* sinct

[0231] In a specific embodiment, a=1 .7, b=0.9, c =8. And the spiral extends from t=2 to t=4 (with units being in mm). It will be appreciated that various sizes and angles of spirals are possible.

[0232] Such a heating element, e.g. a spiral heating element, is of particular benefit when combined with the perforated chamber 300 described above since this element is able to heat a substance in the chamber more intensely than a substance outside of the chamber. Therefore, the combination of the spiral heating element and the perforated chamber provides efficient heating of the substance in the chamber.

[0233] More generally, the heating device may comprise a heating element that is arranged to provide a greater heating output at, or near, a central portion than at an outer portion (e.g. by comprising more material at a central portion than at an outer portion).

[0234] The heating element may be arranged to have a first density of material within a first radius of a center of the heating device 100 (and / or of the perforated chamber 300) and a second density of material within a second, larger, radius of a center of the heating device (and / or of the perforated chamber). In particular, the heating element may comprise a relatively dense section of material adjacent the thermal interface 308 so as to provide a large amount of heat input to the perforated chamber. The heating element may comprise a relatively less dense portion away from the thermal interface.

[0235] As shown in Figure 11 b, which shows the underside of the heating element that faces away from the cavity of the heating device, the heating element may comprise one or more of:

[0236] A base 402, e.g. a pressed base. In particular, the heating element may comprise a pressed base with a heating component such as a heating coil being soldered and / or brazed onto the underside of the base.

[0237] A recess 404 to accommodate the perforated chamber 300 (or more generally, a chamber of the heating device). In particular, a central portion of the heating element may comprise a recess arranged to accommodate the perforated chamber. The heating element may further comprise an attachment (e.g. a clip) for securing the perforated chamber within the recess. In some embodiments, the attachment comprises a catch that is activated when the perforated chamber is pushed into the recess where this catch must be released, e.g. using a button on the exterior of the heating device, before the perforated chamber can be removed from the recess.

[0238] The recess may comprise, or be adjacent to, the thermal interface 308 that is present between the heating element and the perforated chamber 300. Therefore, the recess can ensure efficient heating of the perforated chamber. The recess may accommodate a lower portion of the perforated chamber so that the heating element is able to provide heat to one or more of: the base of the perforated chamber; and a lower section of the sides of the perforated chamber.

[0239] Typically, the recess 404 comprises a section of the base 402. Manufacturing the heating element may then comprise obtaining a flat plate of metal, pressing the plate to form the recess, and then attaching a heating component (e.g. an electrical wire) onto the plate.

[0240] An outer spiral 406 section that ensures sufficient thermal energy is transferred to the cavity to achieve quick ‘bulk boiling’ of a substance in the cavity.

[0241] An inner spiral 408 and / or raised spiral section that is arranged to deliver focused heat transfer to a central part of the heating device and / or to the perforated chamber 300. The inner spiral is typically located adjacent the recess. The inner spiral may provide an extended thermal path with a focused heat flux to ensure more vigorous boiling within the perforated chamber (than occurs outside of the perforated chamber).

[0242] In some embodiments, the heating component of the heating element is provided as a single component (that provides both of the outer spiral 406 and the inner spiral 408 (this is shown in Figure 11 b). This may involve the heating component traversing two different elevations (to lie flat against both the recessed and the non-recessed sections of the base 402).

[0243] In some embodiments, the heating component comprises a plurality of sub-components. For example, the outer spiral 406 and the inner spiral 408 may be provided as different components (and may be controlled together or separately, e.g. so that the outer spial and inner spiral can each be turned on and off separately). Separate heating sub-components may be provided for the recessed and the nonrecessed sections of the base 402.

[0244] Such an embodiment with a heating component that comprises a plurality of sub-components is shown in Figure 11 c. This figure shows a first heating component 406 (the outer spiral) that has a first circumference or radius and a, separate, second heating component 408 (the inner spiral) that has a second circumference or radius. The second circumference / radius is smaller than the first circumference / radius. The first heating component can be used to facilitate bulk heating of fluid in the heating device while the second heating component can be used to provide focused heating to a central portion of the heating device, e.g. to ensure boiling occurs within the perforated chamber 300. While the inner spiral and the outer spiral are typically arranged about a central point of the heating device, it will be appreciated that the first heating component 406 and the second heating component 408 may be offset from this point. Furthermore, while the heating components are typically spirals, other shapes may be used (e.g. a square or linear heating component may be provided. Therefore, generally, this aspect of the disclosure relates to a heating element that comprises: a first component for providing a first heat flux to a first portion of a heating device; and a second component for providing a second heat flux to a second portion of the heating device, where the second heating flux is greater than the first heating flux so as to ensure relatively high heating of the second portion (e.g. the thermal interface 308 adjacent the perforated chamber 300).

[0245] In particular, the above-described heating element can provide both a zone of high heat flux that encourages boiling within the perforated chamber 300 and also a zone of significant heat flux that ensures there is sufficient total heat flux in the heating device to provide significant heating to the entirety of a substance in the cavity of the heating device. For example, the total heat flux may be at least 2kW or at least 3 kW.

[0246] Alternatives and modifications

[0247] It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

[0248] For example, while the detailed description has primarily considered a device for making chai, it will be appreciated that the device could be used for numerous other purposes. For example, the device could be used for heating soup, for brewing coffee, etc. In general, the device is suitable for heating substances, particularly fluids, and more particularly liquids. In some embodiments, the device may be used (additionally or alternatively) for heating solids.

[0249] Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.

Claims

Claims1 . A heating device comprising: a cavity; a perforated chamber, the perforated chamber being mountable within the cavity of the heating device; a heating element for causing a heating of a substance in the cavity and / or the perforated chamber; wherein the heating element is arranged to cause boiling of a fluid within the perforated chamber.

2. The heating device of any preceding claim, wherein the perforated chamber is arranged to be mountable so as to be in thermal contact with a contact surface of the heating device, the contact surface being associated with the heating element.

3. The heating device of any of claim 2, wherein the contact surface is located adjacent the heating element of the heating device.

4. The heating device of claim 2 or 3, wherein the contact surface comprises a ferrous surface, preferably wherein the ferrous surface is arranged to be heated by an inductive heating element of the heating device.

5. The heating device of any preceding claim, comprising a biasing structure, the biasing structure being arranged to urge the perforated chamber into contact with the contact surface.

6. The heating device of claim 5, wherein the biasing structure is arranged to interact with the remainder of the perforated chamber such that mounting the perforated chamber within the heating device causes the biasing structure to the perforated chamber into contact with the contact surface, preferably wherein the biasing structure is arranged to interact with a lid of the perforated chamber such that inserting the lid of the biasing structure into the heating device causes the biasing structure to urge the perforated chamber into contact with the contact surface.

7. The heating device of any preceding claim, wherein the perforated chamber comprises a thermal interface, the thermal interface being arranged to contact a contact surface of the heating device.

8. The heating device of any preceding claim, wherein the perforated chamber comprises a sealing structure, the sealing structure being arranged to form a seal between the perforated chamber and a contact surface of the heating device, preferably wherein the sealing structure comprises an O-ring.

9. The heating device of any preceding claim, wherein the perforated chamber is removably mounted within the heating device.

10. The heating device of any preceding claim, comprising a structure for selectively mounting one a plurality of perforated chambers.11 . The heating device of any preceding claim, comprising a plurality of perforated chambers that are mountable within the heating device.

12. The heating device of claim 10 or 11 , wherein: the plurality of perforated chambers are associated with one or more of: different axial lengths; and apertures of different sizes; and / or13. The heating device of any of claims 10 to 12, wherein the plurality of perforated chambers are associated with different uses, preferably wherein one or more of the perforated chambers is suitable for: brewing chai; and / or steaming vegetables; and / or steaming rice.

14. The heating device of any preceding claim, wherein the heating element comprises an inductive heating element, the inductive heating element being arranged to inductively heat the perforated chamber.

15. The heating device of any preceding claim, wherein the perforated chamber is arranged to fit into a recess of the heating device and / or a / the contact surface.

16. The heating device of any preceding claim, wherein: the walls of the perforated chamber comprise apertures, preferably apertures with a size of between 0.02mm and 0.5mm; and / or the perforated chamber comprises a stainless steel and / or nickel mesh.

17. The heating device of any preceding claim, comprising one or more of: an inner liner that is removable from the perforated chamber, preferably wherein the inner liner comprises apertures that are smaller than apertures of the walls of the perforated chamber; and a lid, preferably wherein the lid comprises a mounting structure, more preferably wherein the mounting structure comprises a threaded structure.

18. The heating device of any preceding claim, being IP-rated such that the heating device can be washed in a dishwasher.

19. The heating device of any preceding claim, wherein the control unit is arranged to determine a temperature of a substance within the heating device and / or the perforated chamber, preferably wherein the control unit is arranged to determine a temperature of one or more component substances of the substance, preferably wherein the control unit is arranged to determine the temperature based on a change in the temperature of the substance that occurs when a unit input of power is provided to the heating element (e.g. dT / dP).

20. The heating device of any preceding claim, comprising: a multiphase level sensor for determining a level in the cavity and / or the perforated chamber of each of a plurality of component substances of the substance; and a control unit for controlling the heating element in dependence on one or more of the determined levels; preferably, wherein: the control unit is arranged to control the heating element in dependence on the highest level present in the cavity; and / or the multiphase level sensor is arranged to determine a level in the cavity of a froth; and the control unit is arranged to control the heating level in dependence on the determined level of froth, preferably wherein the control unit is arranged to control the heating level in dependence on: the determined level of froth exceeding a first threshold level; and / or the determined level of froth falling below a second threshold level.21 . The heating device of claim 20, wherein the control unit is arranged to determine one or more of: a phase, a density, and / or a temperature of one or more of the component substances of the substance based on a reading from the multiphase level sensor.

22. The heating device of claim 20 or 21 , wherein a / the control unit is arranged to determine one or more of: whether a (e.g. highest) level of the substance exceeds a maximum threshold level; and / or whether a (e.g. lowest) level of the substance is below a minimum threshold level.

23. The heating device of any preceding claim, comprising a heating element that is arranged to provide a greater heating output at a central portion than at an outer portion, preferably comprising a spiral heating element, more preferably comprising a logarithmic spiral heating element.

24. The heating device of any preceding claim, wherein the heating element comprise a recessed section, preferably a recessed section for accommodating and / or securing the perforated chamber.

25. The heating device of any preceding claim, being a chai maker.

26. The heating device of any preceding claim, being arranged to receive a capsule containing the substance.

27. A heating device comprising: a cavity for receiving a substance; a heating element for heating the substance; a multiphase level sensor for determining a level in the cavity of each of a plurality of component substances of the substance; and a control unit for controlling the heating element in dependence on one or more of thedetermined levels.

28. A capsule for the heating device of any preceding claim, preferably wherein the capsule comprises a chai mix.

29. A multiphase level sensor for: determining a level of a plurality of component substances in a cavity; and controlling a heating element in dependence on one or more of the determined levels.

30. A structure, preferably a lid, arranged to be retrofitted to a heating device, the structure comprising the multiphase level sensor of claim 29, the structure preferably further comprising the heating element.31 . A control unit of a heating device, wherein the heating device comprises a cavity for receiving a substance and a hearing element for heating the substance, and wherein the control unit is arranged to determine a temperature of the substance based on a determination of a change in the temperature of the substance that occurs when a unit input of power is provided to the heating element (e.g. dT / dP).

32. A kit of parts comprising: a heating device comprising: a cavity for receiving a substance; and a heating element for heating the substance; a multiphase level sensor for determining a level in the cavity of a plurality of component substances of the substance; and a control unit for controlling the heating element in dependence on one or more of the determined levels.

33. A method of operating a heating device comprising a cavity and a heating element, the method comprising: detecting a substance in the cavity; determining a level in the cavity of each of a plurality of component substances of the substance; and controlling the heating element in dependence on one or more of the determined levels.

34. A method of determining a temperature of a substance in a cavity based on a determination of a change in the temperature of the substance that occurs when a unit input of power is provided to a heating element arranged to heat the substance (e.g. dT / dP), preferably further comprising changing a power provided to the heating element based on the determined temperature.

35. A perforated chamber for use with a heating device, the perforated chamber comprising: a mounting structure for mounting the perforated chamber in a cavity of the heating device such that the operation of the heating element is arranged to cause boiling of a fluid within the perforated chamber.

36. A structure, preferably a lid, arranged to be retrofitted to a heating device, the structure comprising the perforated chamber of claim 35.

37. A kit of parts comprising a heating device and at least one perforated chamber according to claim 35, preferably comprising a plurality of perforated chambers, more preferably wherein each of the plurality of perforated chambers is associated with one or more of: different axial lengths; and apertures of different sizes.

Images