Aerosol-generating device with thermally conductive element

Abstract

An aerosol-generating device (10) is provided that includes a thermally conductive element (28) that at least partially defines a chamber (16) for receiving at least a portion of an aerosol-generating article (102). The aerosol-generating device (10) also includes an inductor coil (24) extending around at least a portion of the thermally conductive element (28). The aerosol-generating device (10) further comprises a power source (42) and control circuitry (40) connected to the inductor coil (24) and configured to provide an alternating current to the inductor coil (24) such that, in use, the inductor coil (24) generates an alternating magnetic field. The invention also provides an aerosol-generating system (100) comprising the aerosol-generating device (10).

Description

[0001] The present disclosure relates to an aerosol-generating device for receiving an aerosol-generating article and an aerosol-generating system comprising the aerosol-generating device.

[0002] It is known to form an aerosol-forming substrate of an aerosol-generating article by applying heat to the substrate, without burning or incinerating the substrate. The aerosol-generating article may be cylindrical, similar to a cigarette, and the aerosol-forming substrate may comprise a tobacco material. It is also known to apply heat to an aerosol-generating article using a heat source external to the article to heat the article's aerosol-forming substrate.

[0003] However, external heat sources tend to heat the aerosol-forming substrate unevenly. The aerosol-forming substrate closest to the heat source will be heated more than the aerosol-forming substrate in the centre of the aerosol-generating article further away from the heat source.

[0004] It is also known to heat the aerosol-forming substrate of an article using a heat source located within the interior of the aerosol-forming substrate. In some aerosol-generating systems, the internal heat source is inductively heated using an induction coil positioned external to the aerosol-generating article and a susceptor material located within the central region of the aerosol-generating article. Internally heating the aerosol-forming substrate avoids the need for heat to pass through the packaging to reach the aerosol-forming substrate. However, internally heating the aerosol-forming substrate also results in the aerosol-forming substrate being heated in a non-uniform manner, with heating of the substrate being greatest at or proximal to the internal heat source and decreasing as the distance from the internal heat source to the substrate increases.

[0005] Uneven heating of the aerosol-forming substrate may mean that not all available volatile material is released from the aerosol-forming substrate. This is because, when using external or internal heating of the substrate, increasing the level of heat applied to the substrate in order to completely extract the volatile material from the aerosol-forming substrate may result in accidental and undesirable combustion of the substrate near the heat source, which may result in the generation of undesirable compounds and flavors.

[0006] It would therefore be desirable to provide an aerosol-generating device that facilitates efficient and uniform heating of an aerosol-forming substrate without requiring complex heating means.

[0007] According to a first aspect of the present disclosure, there is provided an aerosol-generating device comprising a thermally conductive element at least partially defining a chamber for receiving at least a portion of an aerosol-generating article. The aerosol-generating device further comprises an inductor coil extending around at least a portion of the thermally conductive element. The aerosol-generating device further comprises a power supply and control circuitry connected to the inductor coil and configured to provide an alternating current to the inductor coil such that, in use, the inductor coil generates an alternating magnetic field.

[0008] As used herein, the term "aerosol-generating device" is used to describe a device that interacts with an aerosol-forming substrate to generate an aerosol. Preferably, the aerosol-generating device is a smoking device that interacts with an aerosol-forming substrate to generate an aerosol that can be inhaled directly into the user's lungs through the user's mouth.

[0009] As used herein, the term "thermally conductive element" is used to describe an element comprising one or more thermally conductive materials having a bulk thermal conductivity between about 10 W / m Kelvin and about 500 W / m Kelvin, preferably between about 15 W / m Kelvin and about 400 W / m Kelvin, at 23°C and 50% relative humidity as measured using the Modified Transient Planar Thermal Source (MTPS) method.

[0010] The present inventors have recognized that when an alternating current flows through an inductor coil during use, the inductor coil may exhibit heat losses in the form of resistive heating of the inductor coil. Advantageously, positioning a thermally conductive element may facilitate transfer of resistively generated heat from the inductor coil to an aerosol-forming substrate of an aerosol-generating article received within a chamber. In embodiments in which the inductor coil is used to inductively heat a susceptor material or element positioned within the aerosol-forming substrate, advantageously, the inductive heating of the susceptor element and the resistive heating of the inductor coil may provide simultaneous internal and external heating of the aerosol-forming substrate. Advantageously, the simultaneous internal and external heating of the aerosol-forming substrate may facilitate more uniform heating of the aerosol-forming substrate.

[0011] Preferably, the inductor coil is positioned in direct contact with the outer surface of the thermally conductive element. Advantageously, direct contact between the inductor coil and the thermally conductive element can increase or maximize the conduction of resistively generated heat from the inductor coil to the thermally conductive element.

[0012] Preferably, the heat-conducting element is arranged so that when the aerosol-generating article is inserted into the chamber, the heat-conducting element directly contacts the aerosol-generating article. Advantageously, direct contact between the heat-conducting element and the aerosol-generating article can increase or maximize the conduction of heat from the heat-conducting element to the aerosol-generating article.

[0013] Preferably, at least one of the control circuitry and the thermally conductive element is configured to prevent inductive coupling between the thermally conductive element and the inductor coil during use.

[0014] As used herein, the term "inductive coupling" refers to the heating of a material when penetrated by an alternating magnetic field. Heating can be caused by the generation of eddy currents in the material. Heating can be caused by hysteresis losses.

[0015] The control circuitry can be configured to provide an alternating current in the form of an alternating current having a frequency selected to reduce or prevent inductive coupling between the thermally conductive element and the inductor coil during use. Preferably, the alternating current is provided at a frequency that reduces or prevents inductive coupling between the inductor coil and the thermally conductive element and increases or maximizes inductive coupling between the inductor coil and the susceptor element. The frequency at which inductive coupling occurs will vary depending on the materials, physical properties, and configuration of the inductor coil, the thermally conductive element, and the susceptor element, such as the inductance of the inductor coil and the magnetic permeability of one or more materials forming each of the thermally conductive element and the susceptor element.

[0016] The thermally conductive element may be formed from a material that reduces or prevents inductive coupling between the inductor coil and the thermally conductive element.

[0017] The thermally conductive element may be formed of a non-conductive material, which may include at least one of glass, ceramic, silicone, polymer material, and a composite material including two or more non-conductive materials.

[0018] The term "conductive" is used herein to refer to a material having a 6 Siemens / meter. The terms "non-conductive" and "electrically insulating" are used herein to refer to materials with an electrical conductivity of less than 0.8×10 4 The electrical conductivity of the material is measured in Siemens / meter.

[0019] The thermally conductive element may be formed from a non-inductively heatable material. The non-inductively heatable material may include any of the non-conductive materials described above. The non-inductively heatable material may include a conductive material that exhibits poor inductive coupling with the inductor coil or does not inductively couple with the inductor coil. The non-inductively heatable material may include a metal. The metal may include at least one of aluminum and paramagnetic steel. The paramagnetic steel may include austenitic steel. The thermally conductive element may be formed from 316 stainless steel.

[0020] The thermally conductive element may have any suitable shape. Preferably, the thermally conductive element has a tubular shape. Preferably, the thermally conductive element has a circular cross-sectional shape. The thermally conductive element may have a cylindrical shape with a constant cross-sectional size. The thermally conductive element may have a cylindrical shape, wherein at least a portion of the cylindrical shape has a tapered cross-sectional size. The tapered cross-sectional size may facilitate insertion of the aerosol-generating article into the thermally conductive element.

[0021] The thermally conductive element may be formed from a cylindrical wall of thermally conductive material. The cylindrical wall may have a wall thickness extending in the radial direction. Preferably, the cylindrical wall has a plurality of average thicknesses in the radial direction of at least 0.5 mm, or at least 1 mm, or at least 1.5 mm, or at least 2 mm. Preferably, the cylindrical wall has a plurality of average thicknesses in the radial direction of less than 5 mm, or less than 4 mm, or less than 3 mm, or less than 2 mm.

[0022] The thermally conductive element may be a passive thermally conductive element. In other words, the thermally conductive element may not generate heat on its own. The passive thermally conductive element is merely arranged to conduct heat generated by the resistance of the inductor coil.

[0023] The thermally conductive element may be an active thermally conductive element. In other words, the aerosol generating device may be configured to generate heat by resistive heating of the thermally conductive element.

[0024] In embodiments where the thermally conductive element is an active thermally conductive element, preferably the control circuitry is configured to supply current from the power supply to the thermally conductive element to resistively heat the thermally conductive element.

[0025] The thermally conductive element may comprise an electrically insulating substrate (eg a substantially tubular electrically insulating substrate) and a resistive track on the electrically insulating substrate.The control circuitry may be configured to, in use, provide power from a power supply to the resistive track.

[0026] Suitable electrically insulating materials may include one or more of the following: glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic may comprise mica, alumina, or zirconia.

[0027] Suitable resistive materials may include one or more of the following: semiconductors (such as doped ceramics), electrically "conductive" ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys, and composite materials made from ceramic and metallic materials. Such composite materials may include doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-containing alloys, cobalt-containing alloys, chromium-containing alloys, aluminum-containing alloys, titanium-containing alloys, zirconium-containing alloys, hafnium-containing alloys, niobium-containing alloys, molybdenum-containing alloys, tantalum-containing alloys, tungsten-containing alloys, tin-containing alloys, gallium-containing alloys, manganese-containing alloys, and iron-containing alloys, and superalloys based on nickel, iron, cobalt, stainless steel, and iron-manganese-aluminium based alloys.The resistive track may comprise a heating wire or filament, such as Ni-Cr (nickel-chromium), platinum, tungsten or an alloy wire or filament.

[0028] The thermally conductive element may include a polymer material and at least one of graphite, a graphite-derived material, and hexagonal boron nitride dispersed within the polymer material. The polymer material may be referred to as a polymer matrix. The at least one of the graphite, the graphite-derived material, and hexagonal boron nitride may be present as filler particles within the polymer matrix.

[0029] The polymer material may be or may include at least one of polyetheretherketone (PEEK) and liquid crystal polymer (LCP).The thermally conductive element may include the polymer material in an amount between 22% and 33% by weight of the thermally conductive element.

[0030] The graphite-derived material may include at least one of expanded graphite and graphite nanoplates. The thermally conductive element may include at least one of graphite, graphite-derived material, and hexagonal boron nitride in an amount between 62% and 69% by weight of the thermally conductive element.

[0031] The thermally conductive element may further comprise at least one additive dispersed within the polymer material. The at least one additive may comprise carbon black. The thermally conductive element may comprise the at least one additive in an amount between 5% and 9% by weight of the thermally conductive element. Advantageously, such an actively heated thermally conductive element may be easier to manufacture than other external heaters. In more detail, the inventors have observed that the thermoplastic properties of the polymer matrix may allow the composite polymer to be tailored to be readily ductile so that it is suitable for precise and controlled molding. At the same time, by controlling and adjusting the concentration and distribution of the conductive filler particles dispersed within the polymer matrix, an active thermally conductive element may be advantageously provided that is capable of generating sufficient heat by the Joule effect to efficiently heat the aerosol-forming matrix of an aerosol-generating article to which the thermally conductive element is thermally coupled.

[0032] Without wishing to be bound by theory, the present inventors have discovered that by adjusting the formulation of the polymer matrix and the degree of dispersion of the conductive filler particles within the polymer matrix, it is possible to control the conductivity, and therefore the amount of heat generated by the electrical resistance of the thermally conductive element when a voltage is applied to the thermally conductive element. In particular, by adjusting the relative ratio of conductive filler to polymer within the polymer composite, it is possible to advantageously ensure that thermally conductive elements made from the polymer composite exhibit highly desirable levels of resistivity. Other parameters, such as the length and cross-sectional surface area of ​​the thermally conductive element, can also be adjusted to fine-tune the resistive behavior of the thermally conductive element as a whole.

[0033] Preferably, the chamber comprises an open first end and a closed second end opposite the open first end, through which at least a portion of the aerosol-generating article is insertable into the chamber.

[0034] Preferably, the aerosol-generating device comprises at least one protrusion extending from the closed second end of the chamber into the chamber. Advantageously, the at least one protrusion may abut an upstream end of an aerosol-generating article received in the chamber to space the upstream end of the aerosol-generating article from the closed end of the chamber. Advantageously, spacing the upstream end of the aerosol-generating article from the closed end of the chamber may facilitate airflow into the aerosol-generating article during use.

[0035] The aerosol generating device may comprise a housing, wherein the inductor coil, the thermally conductive element, the power supply, and the control circuitry are positioned within the housing. Preferably, the housing comprises an end wall defining a closed second end of the chamber, wherein at least one protrusion extends from the end wall into the chamber. Preferably, the at least one protrusion is integrally formed with the end wall.

[0036] Preferably, the at least one protrusion comprises at least three protrusions. Advantageously, providing at least three protrusions may facilitate securing and correct positioning of the aerosol-generating article in the chamber. Preferably, the chamber has a longitudinal axis defining a first direction, along which at least a portion of the aerosol-generating article can be inserted into the chamber, wherein the at least three protrusions are equidistantly spaced from one another in a circumferential direction about the longitudinal axis.

[0037] The aerosol-generating device may comprise a susceptor element. Advantageously, providing a susceptor element as part of the aerosol-generating device may eliminate the need to provide a susceptor element for each aerosol-generating article. Advantageously, this may reduce the cost of each aerosol-generating article.

[0038] As used herein, the term "susceptor element" refers to an element comprising a material capable of converting the energy of a magnetic field into heat. When the susceptor element is located in an alternating magnetic field, the susceptor is inductively heated. The heating of the susceptor may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0039] Preferably, the susceptor element is an elongate susceptor element.Preferably, the elongate susceptor element extends from the closed second end of the chamber into the chamber.Preferably, at least a portion of the elongate susceptor element is positioned internally of the inductor coil.

[0040] The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to aerosolize the aerosol-forming substrate. Suitable materials for the susceptor element include graphite, molybdenum, silicon carbide, stainless steel, niobium, and aluminum. Preferably, the susceptor element comprises metal or carbon. Preferably, the susceptor element comprises or is composed of a ferromagnetic material, such as ferritic iron, ferromagnetic alloys (such as ferromagnetic steel or stainless steel), ferromagnetic particles, and ferrites. Suitable susceptor elements may be or include aluminum. The susceptor element preferably comprises greater than about 5%, preferably greater than about 20%, more preferably greater than about 50%, or greater than 90% ferromagnetic or paramagnetic material. Preferred susceptor elements may be heated to a temperature exceeding about 250 degrees Celsius.

[0041] The susceptor element may comprise a non-metallic core with a metallic layer disposed thereon.For example, the susceptor element may comprise one or more metallic tracks formed on the outer surface of a ceramic core or substrate.

[0042] The susceptor element may have a protective outer layer, such as a protective ceramic layer or a protective glass layer. The protective outer layer may encapsulate the susceptor element. The susceptor element may include a protective coating formed of glass, ceramic, or an inert metal formed on a core of the susceptor material.

[0043] The susceptor element may have any suitable cross-section. For example, the susceptor element may have a square, oval, rectangular, triangular, pentagonal, hexagonal, or similar cross-sectional shape. The susceptor element may have a flat or flat cross-sectional shape.

[0044] The susceptor element may be solid, hollow or porous. Preferably, the susceptor element is solid.

[0045] In embodiments where the susceptor element has a flat or flat cross-sectional shape, the susceptor element preferably has a thickness of between about 1 mm and about 8 mm, more preferably between about 3 mm and about 5 mm. The thickness of the susceptor element is measured in the longitudinal direction of the aerosol generating device. Preferably, the susceptor element has a width or diameter of between about 3 mm and about 12 mm, more preferably between about 4 mm and about 10 mm, and more preferably between about 5 mm and about 8 mm. The width or diameter of the susceptor element is orthogonal to its thickness.

[0046] In embodiments where the susceptor element is an elongated susceptor element, the elongated susceptor element is preferably in the form of a pin, rod, blade, or plate. Preferably, the elongated susceptor element has a length of between about 5 mm and about 15 mm, such as between about 6 mm and about 12 mm, or between about 8 mm and about 10 mm. The elongated susceptor element preferably has a width of between about 1 mm and about 8 mm, more preferably between about 3 mm and about 5 mm. The elongated susceptor element may have a thickness of between about 0.01 mm and about 2 mm. If the elongated susceptor element has a constant cross-section, such as a circular cross-section, it preferably has a width or diameter of between about 1 mm and about 5 mm.

[0047] Preferably, the thermally conductive element is formed of a first material and the susceptor element is formed of a second material, wherein the first material is different from the second material. Advantageously, forming the thermally conductive element and the susceptor element from different materials can help reduce or minimize inductive coupling between the inductor coil and the thermally conductive element and increase or maximize inductive coupling between the inductor coil and the susceptor element.

[0048] Preferably, the inductor coil is configured such that when the aerosol-generating article is inserted into the chamber, at least a portion of the aerosol-generating article is received within the inductor coil.

[0049] The inductor coil may be formed from a coiled wire. The wire may include a conductive core and a coating on the conductive core. Preferably, the coating is electrically insulating. Advantageously, the electrically insulating coating prevents electrical shorting between adjacent windings of the inductor coil. Advantageously, the electrically insulating coating electrically isolates the inductor coil from the thermally conductive element. The coating may comprise at least one of a polymer, a ceramic, and a glass. The coating may comprise parylene.

[0050] The inductor coil may be formed from any suitable conductive material. Preferably, the inductor coil is formed from a metal or metal alloy. The inductor coil may be formed from at least one of copper, a copper alloy, a copper-nickel alloy, tungsten, aluminum, an aluminum alloy, and steel. Suitable steels include stainless steel, such as 316 stainless steel. In embodiments where the inductor coil includes a conductive core, the metal or metal alloy may form the conductive core.

[0051] The power supply may be a DC power supply. In one embodiment, the power supply is a DC power supply having a DC supply voltage in the range of about 2.5 volts to about 4.5 volts and a DC supply current in the range of about 1 ampere to about 10 amperes (corresponding to a DC supply in the range of about 2.5 watts to about 45 watts).

[0052] The power supply can be configured to operate at a high frequency. As used herein, the term "high-frequency oscillating current" refers to an oscillating current having a frequency between about 500 kilohertz and about 30 megahertz. The frequency of the high-frequency oscillating current can be about 1 megahertz to about 30 megahertz, preferably about 1 megahertz to about 10 megahertz, and more preferably about 5 megahertz to about 8 megahertz.

[0053] The aerosol generating device includes a control circuit system connected to the inductor coil and a power supply. The control circuit system is configured to control the power supply from the power supply to the inductor coil. The control circuit system may include a microprocessor, a microcontroller or an application specific integrated circuit (ASIC), which may be a programmable microprocessor, or other electronic circuit systems capable of providing control. The control circuit system may include additional electronic components. The control circuit system may be configured to regulate the current supply to the inductor coil. The current can be continuously supplied to the inductor coil after the aerosol generating device is activated, or can be intermittently supplied, such as based on puff by puff. The control circuit system may advantageously include a DC / AC inverter, which may include a Class D or Class E power amplifier.

[0054] The control circuitry may be configured to supply electrical energy as alternating current from a power source to the inductor coil, such that the inductor coil is operable to generate heat through one or a combination of i) resistive heating of the inductor coil and ii) heating of a susceptor element through inductive coupling of the inductor coil to the susceptor. The control circuitry may be configured to adjust at least one parameter of the alternating current to change the inductive coupling of the inductor coil to the susceptor element, thereby adjusting a balance of heat generated through the inductive coupling of the inductor coil to the susceptor element relative to heat generated through resistive heating of the inductor coil.

[0055] Preferably, the at least one parameter comprises the frequency of the alternating current. The inductive coupling between the inductor coil and the susceptor element varies as the frequency of the alternating current varies. The frequency may be adjusted to have a value f associated with the alternating current.susceptor , the alternating current generates an alternating magnetic field that provides optimal coupling with the susceptor element to allow nearly all of the energy to be transferred from the inductor coil to the susceptor element, thereby causing most of the heat to be generated by inductive heating of the susceptor element. The frequency can also be adjusted to have a value f associated with the alternating current. inductor coil , the alternating current produces an alternating magnetic field that provides little or no coupling to the susceptor element and allows nearly all of the energy to be retained within the inductor coil, causing most of the heat to be generated by resistive heating of the inductor coil. The frequency can also be adjusted to have a value f associated with the alternating current. total , which combines inductive heating of the susceptor element with resistive heating of the inductor coil. Each of these frequencies will vary depending on the materials, physical properties, and configuration of the inductor coil and susceptor element, such as the inductance of the inductor coil and the magnetic permeability of the material or materials forming the susceptor element.

[0056] The control circuitry may be configured to provide alternating current to the inductor coil so that the inductor coil generates an alternating magnetic field to inductively heat a susceptor element in the aerosol-generating article, and to provide direct current to the inductor coil to resistively heat the inductor coil and thereby conductively heat the aerosol-generating article via the thermally conductive element. Advantageously, the use of a single coil to provide both heating power to the internal susceptor and resistive heating of the coil itself provides two different heat sources at different locations relative to the aerosol-forming substrate using a structure that is no more complex than a typical induction heating device.

[0057] The control circuitry may be configured to adjust the alternating current provided to the inductor coil during operation of the aerosol generating device to adjust the amount of heating provided by induction heating.

[0058] The control circuitry may be configured to adjust the direct current provided to the inductor coil during operation of the aerosol generating device to adjust the amount of heating provided by the resistive heating.

[0059] The control circuit system can be configured to provide alternating current and direct current to the inductor coil at different times. For example, after activating the aerosol generating device, the control circuit system can be configured to initially provide alternating current to the inductor coil and subsequently provide direct current to the inductor coil. This can provide rapid generation of aerosol at the beginning of use, but also provide complete and efficient heating of the entire aerosol-forming substrate during the entire use process. At the beginning of use, inductive heating of the internal susceptor can provide aerosol faster than external resistive heating because the susceptor can be in closer contact with the aerosol-forming substrate. If the susceptor has a lower thermal mass than the inductor coil, the internal susceptor can also be heated faster than the external inductor coil.

[0060] The control circuitry may be configured to provide alternating current and direct current to the inductor coil in an alternating sequence.It may be beneficial to alternate external and internal heating in order to avoid overheating of any part of the aerosol-forming substrate.

[0061] The control circuitry may be configured to provide both alternating current and direct current to the inductor coil simultaneously. In this way, a greater amount of thermal energy may be transferred to the aerosol-forming substrate to generate a larger volume of aerosol without the susceptor or inductor coil reaching a temperature at which any part of the aerosol-generating article might burn.

[0062] An aerosol generating device comprising control circuitry configured to vary at least one parameter of an alternating current, or configured to provide both alternating and direct current to an inductor coil, the aerosol generating device being capable of varying the pattern of heat applied to an aerosol-forming substrate according to any one of the following heating schemes:

[0063] a) heating solely or predominantly by resistive heating of the inductor coil;

[0064] b) heating of the susceptor element solely or predominantly by inductive coupling of the inductor coil to the susceptor element;

[0065] c) A combination of resistive heating of the inductor coil and heating of the susceptor element by inductive coupling of the inductor coil to the susceptor element.

[0066] Preferably, the aerosol generating device is portable. The aerosol generating device may be of a size comparable to a conventional cigar or cigarette. The aerosol generating device may have an overall length between about 30 mm and about 150 mm. The aerosol generating device may have an outer diameter between about 5 mm and about 30 mm.

[0067] The aerosol generating device housing may be elongated. The housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics, or composite materials comprising one or more of these materials, or thermoplastic materials suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), and polyethylene. Preferably, the material is lightweight and non-brittle.

[0068] The housing may include a mouthpiece. The mouthpiece may include at least one air inlet and at least one air outlet. The mouthpiece may include more than one air inlet. The one or more air inlets may reduce the temperature of the aerosol before it is delivered to the user, and may reduce the concentration of the aerosol before it is delivered to the user.

[0069] Alternatively, a mouthpiece may be provided as part of the aerosol-generating article.

[0070] As used herein, the term "mouthpiece" refers to the part of an aerosol-generating device that is placed in the mouth of a user for direct inhalation of aerosol generated by the aerosol-generating device from an aerosol-generating article received in a chamber of the housing.

[0071] The aerosol-generating device may comprise a user interface for activating the device, such as a button for initiating heating of the device or a display for indicating the status of the device or aerosol-forming substrate.

[0072] According to a second aspect of the present disclosure, there is provided an aerosol generating system. According to any embodiment described herein, the aerosol generating system comprises an aerosol generating device according to the first aspect of the present disclosure. The aerosol generating system further comprises an aerosol generating article, the aerosol generating article comprising an aerosol-forming substrate.

[0073] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol. The aerosol-generating article may be disposable.

[0074] As used herein, the term "aerosol-forming substrate" refers to a substrate consisting of or comprising an aerosol-forming material that is capable of releasing volatile compounds upon heating to generate an aerosol.

[0075] The aerosol-generating article may comprise an article susceptor element. Preferably, the article susceptor element is positioned in direct contact with the aerosol-forming substrate. Preferably, the article susceptor element is an internal susceptor element positioned within the aerosol-forming substrate.

[0076] Preferably, the aerosol-generating article is configured such that when the aerosol-generating article is inserted into the chamber of the aerosol-generating device, at least a portion of the article susceptor element is positioned within the inductor coil.

[0077] The article susceptor element may comprise any of the optional or preferred features described above in relation to a susceptor element forming part of an aerosol-generating device.

[0078] Preferably, the thermally conductive element is formed of a first material and the article susceptor element is formed of a second material, wherein the first material is different from the second material. Advantageously, forming the thermally conductive element and the article susceptor element from different materials can help reduce or minimize inductive coupling between the inductor coil and the thermally conductive element and increase or maximize inductive coupling between the inductor coil and the article susceptor element.

[0079] Preferably, the aerosol-forming substrate is a solid aerosol-forming substrate. However, the aerosol-forming substrate may comprise both a solid component and a liquid component. Alternatively, the aerosol-forming substrate may be a liquid aerosol-forming substrate.

[0080] Preferably, the aerosol-forming substrate comprises nicotine. More preferably, the aerosol-forming substrate comprises tobacco. Alternatively or additionally, the aerosol-forming substrate may comprise an aerosol-forming material that does not contain tobacco.

[0081] If the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate may comprise, for example, one or more of a powder, granules, pellets, shreds, strips, ribbons or sheets comprising one or more of herb leaves, tobacco leaves, tobacco ribs, expanded tobacco and homogenised tobacco.

[0082] Alternatively, the solid aerosol-forming substrate may comprise tobacco volatile flavor compounds or non-tobacco volatile flavor compounds that are released upon heating the solid aerosol-forming substrate. The solid aerosol-forming substrate may also comprise one or more capsules, e.g., comprising additional tobacco volatile flavor compounds or non-tobacco volatile flavor compounds, and such capsules may melt during heating of the solid aerosol-forming substrate.

[0083] Alternatively, the solid aerosol-forming substrate can be arranged on a thermally stable carrier or embedded in a thermally stable carrier. The carrier can take the form of a powder, granules, pellets, fragments, filaments, strips or sheets. The solid aerosol-forming substrate can be deposited on the surface of the carrier in the form of, for example, a sheet, foam, gel or slurry. The solid aerosol-forming substrate can be deposited on the entire surface of the carrier, or alternatively, can be deposited in a certain pattern to provide uneven fragrance delivery during use.

[0084] In preferred embodiments, the aerosol-forming substrate comprises homogenised tobacco material.As used herein, the term "homogenised tobacco material" refers to material formed by agglomerating particulate tobacco.

[0085] Preferably, the aerosol-forming substrate comprises an aggregated sheet of homogenised tobacco material. As used herein, the term "sheet" refers to a laminar element whose width and length are significantly greater than its thickness. As used herein, the term "aggregated" is used to describe a sheet that is substantially transverse to the longitudinal axis of the aerosol-generating article and is wound, folded or compressed or tightened. Preferably, the aerosol-forming substrate comprises an aerosol-forming agent. As used herein, the term "aerosol-forming agent" is used to describe any suitable known compound or mixture of compounds that contributes to the formation of an aerosol in use and is substantially resistant to thermal degradation at the operating temperature of the aerosol-generating article.

[0086] Suitable aerosol formers are known in the art and include, but are not limited to, polyols such as propylene glycol, triethylene glycol, 1,3-butylene glycol, and glycerol; esters of polyols such as glycerol mono-, di-, or triacetate; and aliphatic esters of mono-, di-, or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate. Preferred aerosol formers are polyols or mixtures thereof such as propylene glycol, triethylene glycol, 1,3-butylene glycol, and most preferably glycerol.

[0087] The aerosol-forming substrate may comprise a single aerosol-forming agent. Alternatively, the aerosol-forming substrate may comprise a combination of two or more aerosol-forming agents.

[0088] The present invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0089] Example Ex1: An aerosol generating device comprising:

[0090] a thermally conductive element at least partially defining a chamber for receiving at least a portion of an aerosol-generating article;

[0091] an inductor coil extending around at least a portion of the thermally conductive element; and

[0092] A power supply and control circuitry are connected to the inductor coil and configured to provide an alternating current to the inductor coil such that, in use, the inductor coil generates an alternating magnetic field.

[0093] Example Ex2: An aerosol generating device according to Example 1, wherein the inductor coil is positioned in direct contact with the outer surface of the thermally conductive element.

[0094] Example Ex3: An aerosol-generating device according to example 1 or 2, wherein the thermally conductive element is arranged such that when the aerosol-generating article is inserted into the chamber, the thermally conductive element directly contacts the aerosol-generating article.

[0095] Example Ex4: An aerosol-generating device according to example 1, 2, or 3, wherein at least one of the control circuitry and the thermally conductive element is configured to prevent inductive coupling between the thermally conductive element and the inductor coil during use.

[0096] Example Ex5: An aerosol-generating device according to any preceding example, wherein the control circuitry is configured to provide an alternating current in the form of an alternating current having a frequency selected to prevent inductive coupling between the thermally conductive element and the inductor coil during use.

[0097] Example Ex6: An aerosol-generating device according to any preceding example, wherein the thermally conductive element is formed of a non-conductive material.

[0098] Example Ex7: An aerosol-generating device according to any preceding example, wherein the thermally conductive element is formed of a non-inductively heatable material.

[0099] Example Ex8: An aerosol-generating device according to any preceding example, wherein the thermally conductive element comprises at least one of a polymer material and a metal.

[0100] Example Ex9: An aerosol-generating device according to any preceding example, wherein the thermally conductive element comprises at least one of aluminum and paramagnetic steel.

[0101] Example Ex10: An aerosol generating device according to Example 9, wherein the paramagnetic steel comprises austenitic steel.

[0102] Example Ex11: An aerosol-generating device according to any preceding example, wherein the thermally conductive element comprises a polymer material and at least one of graphite, a graphite-derived material, and hexagonal boron nitride dispersed within the polymer material.

[0103] Example Ex12: An aerosol-generating device according to Example 11, wherein the polymer material comprises at least one of polyetheretherketone (PEEK) and liquid crystal polymer (LCP).

[0104] Example Ex 13: An aerosol generating device according to example 11 or 12, wherein the thermally conductive element comprises the polymer material in an amount between 22% and 33% by weight of the thermally conductive element.

[0105] Example Ex 14: An aerosol generating device according to Example 11, 12 or 13, wherein the graphite-derived material comprises at least one of expanded graphite and graphite nanoplates.

[0106] Example Ex15: An aerosol-generating device according to any one of Examples 11 to 14, wherein the thermally conductive element comprises at least one of graphite, graphite-derived materials, and hexagonal boron nitride in an amount between 62% and 69% by weight of the thermally conductive element.

[0107] Example Ex16: An aerosol-generating device according to any one of Examples 11 to 15, wherein the thermally conductive element further comprises at least one additive dispersed within the polymer material.

[0108] Example Ex 17: An aerosol generating device according to Example 16, wherein the at least one additive comprises carbon black.

[0109] Example Ex 18: An aerosol-generating device according to Example 16 or 17, wherein the thermally conductive element comprises the at least one additive in an amount between 5% and 9% by weight of the thermally conductive element.

[0110] Example Ex19: An aerosol-generating device according to any preceding example, wherein the power supply and the control circuitry are connected to the thermally conductive element and are configured to provide current to the thermally conductive element to resistively heat the thermally conductive element during use.

[0111] Example Ex20: An aerosol-generating device according to any preceding example, wherein the chamber comprises an open first end and a closed second end opposite the open first end, at least a portion of the aerosol-generating article being insertable into the chamber through the open first end.

[0112] Example Ex21: An aerosol generating device according to Example 20, further comprising at least one protrusion extending from the closed second end of the chamber into the chamber.

[0113] Example Ex22: An aerosol generating device according to Example 21, wherein the at least one protrusion comprises at least three protrusions.

[0114] Example Ex23: An aerosol generating device according to Example 22, wherein the chamber has a longitudinal axis defining a first direction, at least a portion of the aerosol generating article can be inserted into the chamber along the first direction, and wherein the at least three protrusions are equally spaced from each other in a circumferential direction around the longitudinal axis.

[0115] Example Ex24: An aerosol-generating device according to any preceding example, further comprising a housing, wherein the inductor coil, the thermally conductive element, the power supply, and the control circuitry are positioned within the housing.

[0116] Example Ex25: An aerosol generating device according to the combination of Example 24 and any one of Examples 20 to 23, wherein the housing comprises an end wall defining the closed second end of the chamber, and wherein the at least one protrusion extends from the end wall into the chamber.

[0117] Example Ex26: An aerosol generating device according to Example 25, wherein the at least one protrusion is integrally formed with the end wall.

[0118] Example Ex27: An aerosol-generating device according to any one of Examples 20 to 26, further comprising an elongated susceptor element extending from the closed second end of the chamber into the chamber.

[0119] Example Ex28: An aerosol-generating device according to Example 27, wherein at least a portion of the elongated susceptor element is positioned inside the inductor coil.

[0120] Example Ex29: An aerosol-generating device according to example 27 or 28, wherein the thermally conductive element is formed of a first material, wherein the elongated susceptor element is formed of a second material, and wherein the first material is different from the second material.

[0121] Example Ex30: An aerosol-generating device according to any preceding example, wherein the inductor coil is arranged such that when an aerosol-generating article is inserted into the chamber, at least a portion of the aerosol-generating article is received within the inductor coil.

[0122] Example Ex31: An aerosol generating system, comprising:

[0123] An aerosol generating device according to any preceding embodiment; and

[0124] An aerosol-generating article comprising an aerosol-forming substrate.

[0125] Example Ex32: An aerosol-generating system according to Example 31, wherein the aerosol-generating article is configured such that when the aerosol-generating article is inserted into the chamber, at least a portion of the aerosol-forming substrate is positioned within the thermally conductive element.

[0126] Example Ex33: An aerosol-generating system according to example 31 or 32, wherein the aerosol-generating article further comprises an article susceptor element.

[0127] Example Ex34: An aerosol-generating system according to Example 33, wherein the aerosol-generating article is configured such that when the aerosol-generating article is inserted into the chamber, at least a portion of the article susceptor element is positioned within the inductor coil.

[0128] Example Ex35: An aerosol-generating system according to example 33 or 34, wherein the thermally conductive element is formed of a first material, wherein the article susceptor element is formed of a second material, and wherein the first material is different from the second material.

[0129] The present invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

[0130] Figure 1shows a side cross-sectional view of an aerosol generating device according to a first embodiment of the present invention;

[0131] Figure 2 Shown is a view taken along line 1-1 Figure 1 An axial cross-sectional view of an aerosol generating device;

[0132] Figure 3 Shown include Figure 1 A side sectional view of an aerosol generating system of an aerosol generating device;

[0133] Figure 4 shows a side cross-sectional view of an aerosol generating device according to a second embodiment of the present invention; and

[0134] Figure 5 Shown include Figure 4 A side cross-sectional view of an aerosol generating system of an aerosol generating device.

[0135] Figure 1 and Figure 2 An aerosol-generating device 10 according to a first embodiment of the present invention is shown. The aerosol-generating device 10 comprises a housing 12 which partially defines a chamber 16 for receiving a portion of an aerosol-generating article. The chamber 16 comprises an open end 18 through which the aerosol-generating article can be inserted, and a closed end 20 opposite the open end 18.

[0136] The aerosol-generating device also includes a thermally conductive element 28 in the form of an austenitic steel tube. The thermally conductive element 28 partially defines the cylindrical wall 22 of the chamber 16 extending between the open end 18 and the closed end 20. The thermally conductive element 28 is arranged so that when an aerosol-generating article is inserted into the chamber 16, the aerosol-generating article is received within the thermally conductive element 28 and is in direct contact with the thermally conductive element 28. Advantageously, the direct contact between the thermally conductive element 28 and the aerosol-generating article promotes heat transfer from the thermally conductive element 28 to the aerosol-generating article.

[0137] An inductor coil 24 comprising a plurality of windings 26 extends around an outer surface of a thermally conductive element 28. The inductor coil 24 is arranged such that the plurality of windings are in direct contact with the outer surface of the thermally conductive element 28. Advantageously, positioning the inductor coil 24 in direct contact with the outer surface of the thermally conductive element 28 facilitates transferring heat generated by resistive heating of the inductor coil 24 to the thermally conductive element 28. The inductor coil 24 and the thermally conductive element 28 are concentrically arranged about a central axis 36 of the aerosol generating device 10.

[0138] As in Figure 2As shown in , the thermally conductive element 28 defines a plurality of channels 30 in the inner surface of the thermally conductive element. Advantageously, the channels 30 facilitate airflow through the chamber 16 when the aerosol-generating article is received within the chamber 16. Figure 1 and Figure 2 In the embodiment shown, the thermally conductive element 28 defines three channels 30 equally spaced about a central axis 36 of the aerosol generating device 10. Skilled persons will appreciate that the thermally conductive element 28 may define more or fewer channels 30 and that the arrangement of the protrusions 38 about the central axis 36 may vary.

[0139] The housing 12 further defines a plurality of protrusions 38 extending from the closed end 20 of the chamber 16 into the chamber 16. As will be described further below, the plurality of protrusions 38 serve to maintain a gap between the end of the aerosol-generating article and the closed end 20 of the chamber 16 when the aerosol-generating article is fully inserted into the chamber 16. Figure 1 and Figure 2 In the embodiment shown, the housing 12 defines three protrusions 38 equally spaced about the central axis 36 of the aerosol generating device 10. The skilled person will appreciate that the housing 12 may define more or fewer protrusions 38, and that the arrangement of the protrusions 38 at the closed end 20 of the chamber 16 may vary.

[0140] The aerosol generating device 10 further comprises control circuitry 40 and a power source 42 connected to the inductor coil 24. The control circuitry 40 is configured to provide an alternating current from the power source 42 to the inductor coil 24 to generate an alternating magnetic field.

[0141] Figure 3 Shown include Figure 1 10 and an aerosol-generating article 102.

[0142] The aerosol-generating article 102 comprises an aerosol-forming substrate 104 in the form of a tobacco rod, a first hollow acetate tube 106, a second hollow acetate tube 108, a mouthpiece 110, and an outer wrapper 112. The aerosol-generating article 102 also comprises a susceptor element 114 disposed within the aerosol-forming substrate 104. During use, a portion of the aerosol-generating article 102 is inserted into the chamber 16 such that the aerosol-forming substrate 104 and the susceptor element 114 are positioned within the thermally conductive element 28 and the inductor coil 24. The control circuitry 40 provides an alternating current from the power supply 42 to the inductor coil 24 to generate an alternating magnetic field, which inductively heats the susceptor element 114, which heats the aerosol-forming substrate 104 to generate an aerosol. In addition, heat generated in the inductor coil 24 itself by resistive losses in the inductor coil 24 is conducted from the inductor coil 24 to the aerosol-forming substrate 104 by the thermally conductive element 28.

[0143] The airflow through the aerosol generating system 100 during use is determined by Figure 3 102 , a plurality of protrusions 38 are provided to facilitate the flow of air into the aerosol-generating article 102. The ...

[0144] Figure 4 FIG2 shows a cross-sectional view of an aerosol generating device 150 according to a second embodiment of the present invention. Figure 1 and Figure 2 The aerosol generating device 10 is described hereinafter and like reference numerals are used to identify like parts.

[0145] The aerosol-generating device 150 differs from the aerosol-generating device 10 by the addition of a susceptor element 164. The susceptor element 164 has an elongated shape and extends from the closed end 20 of the chamber 16 into the chamber 16. The susceptor element 164 extends along the central axis 36 of the aerosol-generating device 150, such that the inductor coil 24 and the thermally conductive element 28 extend concentrically around the susceptor element 164.

[0146] Figure 5 Shown include Figure 4 1 and 172. The aerosol generating system 170 is similar to that of the aerosol generating device 150 and the aerosol generating article 172 of FIG. Figure 3 The aerosol generating system 100 is described hereinafter and like reference numerals are used to refer to like parts.

[0147] The aerosol generating system 170 differs in that there is no susceptor element in the aerosol generating article 172. When the aerosol generating article 172 is inserted into the chamber 16, the susceptor element 164 of the aerosol generating device 150 is received within the aerosol-forming substrate 104 of the aerosol generating article 172. Once the aerosol generating article 172 has been inserted into the chamber 16, the operation of the aerosol generating system 170 is similar to that of the aerosol generating article 172. Figure 3 The operation of the aerosol generating system 100 described is the same.

Claims

1. An aerosol generating device comprising: a thermally conductive element at least partially defining a chamber for receiving at least a portion of the aerosol-generating article, wherein the thermally conductive element is formed of at least one of a non-conductive material and a non-inductively heatable material; an inductor coil extending around at least a portion of the thermally conductive element; as well as A power supply and control circuitry are connected to the inductor coil and configured to provide an alternating current to the inductor coil such that, in use, the inductor coil generates an alternating magnetic field. 2 . An aerosol generating device according to claim 1 , wherein the power supply and the control circuitry are connected to the thermally conductive element and are configured to provide an electric current to the thermally conductive element to resistively heat the thermally conductive element during use.

3. An aerosol generating device comprising: a thermally conductive element at least partially defining a chamber for receiving at least a portion of an aerosol-generating article; an inductor coil extending around at least a portion of the thermally conductive element; as well as a power supply and control circuitry, wherein the power supply and control circuitry are connected to the inductor coil and are configured to provide an alternating current to the inductor coil such that, in use, the inductor coil generates an alternating magnetic field, and wherein the power supply and control circuitry are connected to the thermally conductive element and are configured to provide a current to the thermally conductive element to resistively heat the thermally conductive element during use.

4. An aerosol generating device according to claim 3, wherein the thermally conductive element is formed from at least one of a non-conductive material and a non-inductively heatable material.

5. An aerosol-generating device according to any preceding claim, wherein the inductor coil is positioned in direct contact with an outer surface of the thermally conductive element.

6. An aerosol-generating device according to any preceding claim, wherein the thermally conductive element is arranged such that when an aerosol-generating article is inserted into the chamber, the thermally conductive element directly contacts the aerosol-generating article.

7. An aerosol generating device according to any preceding claim, wherein at least one of the control circuitry and the thermally conductive element is configured to prevent inductive coupling between the thermally conductive element and the inductor coil during use.

8. An aerosol generating device according to any preceding claim, wherein the control circuitry is configured to provide an alternating current in the form of an alternating current having a frequency selected to prevent inductive coupling between the thermally conductive element and the inductor coil during use.

9. An aerosol-generating device according to any preceding claim, wherein the thermally conductive element comprises at least one of a polymeric material and a metal.

10. An aerosol-generating device according to any preceding claim, wherein the thermally conductive element comprises at least one of aluminium and paramagnetic steel, optionally wherein the paramagnetic steel comprises austenitic steel.

11. An aerosol generating device according to any preceding claim, wherein the chamber comprises an open first end and a closed second end opposite the open first end, and at least a portion of an aerosol generating article can be inserted into the chamber through the open first end, optionally wherein the aerosol generating device comprises at least one protrusion extending from the closed second end of the chamber into the chamber.

12. An aerosol-generating device according to any preceding claim, further comprising a susceptor element.

13. An aerosol generating device according to claim 12, wherein the thermally conductive element is formed from a first material, wherein the susceptor element is formed from a second material, and wherein the first material is different from the second material.

14. An aerosol generating system, comprising: An aerosol generating device according to any preceding claim; as well as An aerosol-generating article comprising an aerosol-forming substrate.

15. An aerosol-generating system according to claim 14, wherein the aerosol-generating article further comprises an article susceptor element.

16. An aerosol generating system according to claim 15, wherein the thermally conductive element is formed from a first material, wherein the article susceptor element is formed from a second material, and wherein the first material is different from the second material.

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