WO2024110318A1

WO2024110318A1 - Aerosol-generating device with planar heating assemblies

Info

Publication number: WO2024110318A1
Application number: PCT/EP2023/082137
Authority: WO
Inventors: Rui Nuno Rodrigues Alves BATISTA; Cristina Ferraz Rigo; Semen GURALEVYCH; Valerio OLIANA
Original assignee: Philip Morris Products S.A.
Priority date: 2022-11-24
Filing date: 2023-11-16
Publication date: 2024-05-30

Abstract

An aerosol-generating system comprising: an aerosol-generating article (20) and an aerosol-generating device (1). The aerosol-generating article (20) comprises: a housing (23) defining a substrate cavity (201); and an aerosol-forming substrate (21) arranged in the substrate cavity (201). The aerosol-generating device (1) comprises: a heating cavity (3) configured to receive at least a portion of the aerosol-generating article (20), the heating cavity (3) being defined at one side by a planar cavity surface (4) extending substantially in a plane; a first heating assembly (6) comprising a planar first heating element extending substantially in a first plane parallel to the plane of the cavity surface; and a second heating assembly (7) comprising a planar second heating element extending substantially in a second plane parallel to the plane of the cavity surface.

Description

AEROSOL-GENERATING DEVICE WITH PLANAR HEATING ASSEMBLIES

The disclosure relates to an aerosol-generating device and an aerosol-generating system comprising an aerosol-generating device.

Some known aerosol-generating systems comprise an aerosol-generating device having a power supply, such as a battery, a controller, and a heating element for heating an aerosolforming substrate. In some examples, the aerosol-forming substrate comprises a tobacco rod or a tobacco plug that is arranged in an aerosol-generating article. In use, the aerosolgenerating article is inserted into a cavity of the aerosol-generating device, and the heating element either penetrates the aerosol-forming substrate or is arranged around the outside of the aerosol-forming substrate. Power is supplied to the heating element from the power supply to heat the aerosol-forming substrate, and volatile components of the aerosol-forming substrate are vaporised and released and condense to form an aerosol, which is inhalable by a user. In some such aerosol-generating systems, the aerosol-generating article resembles a conventional cigarette, having a similar cylindrical stick like configuration.

It would be desirable to provide an aerosol-generating system that is able to heat more than one aerosol-forming substrate to improve the control a user has over the aerosol generated by the aerosol-generating system. It would also be desirable to provide an aerosolgenerating system that is even more compact, and easier to manufacture.

According to the disclosure there is provided an aerosol-generating system comprising an aerosol-forming substrate and an aerosol-generating device. The aerosol-generating system may further comprise an aerosol-generating article comprising the aerosol-forming substrate. The aerosol-generating article may comprise a housing defining a substrate cavity. The aerosol-forming substrate may be arranged in the substrate cavity. The aerosol-generating device may comprise: a heating cavity configured to receive at least a portion of the aerosolgenerating article. The heating cavity may be defined at one side by a planar cavity surface extending substantially in a plane. The aerosol-generating device may comprise a first heating assembly comprising a planar first heating element extending substantially in a first plane. The first plane may be parallel to the plane of the cavity surface. The aerosol-generating device may comprise a second heating assembly comprising a planar second heating element extending substantially in a second plane. The second plane may be parallel to the plane of the cavity surface.

According to the disclosure there is provided an aerosol-generating system comprising an aerosol-forming substrate and an aerosol-generating device. The aerosol-generating system further comprises an aerosol-generating article comprising a housing defining a substrate cavity. The aerosol-generating article further comprises an aerosol-forming substrate arranged in the substrate cavity. The aerosol-generating device comprises: a heating cavity configured to receive at least a portion of the aerosol-generating article. The heating cavity is defined at one side by a planar cavity surface extending substantially in a plane. The aerosol-generating device comprises a first heating assembly comprising a planar first heating element extending substantially in a first plane. The first plane is parallel to the plane of the cavity surface. The aerosol-generating device comprises a second heating assembly comprising a planar second heating element extending substantially in a second plane. The second plane is parallel to the plane of the cavity surface.

Advantageously, an aerosol-generating device with a heating cavity having a planar cavity surface and two heating assemblies, each heating assembly having a planar heating element extending in a plane parallel to the cavity surface may provide a compact device that enables efficient heat transfer from the heating assemblies to an aerosol-forming substrate in the heating cavity.

In some embodiments, the first plane and the second plane are coplanar. In other words, in some embodiments the first plane and the second plane are the same plane. The first planar heating element and the second planar heating element may extend in the same plane. In some of these embodiments, the first plane and the second plane are coplanar with the plane of the cavity surface. In other words, in some of these embodiments the first plane, the second plane and the plane of the cavity surface are the same plane. The first planar heating element and the second planar heating element may extend in the plane of the cavity surface. The first heating element may be arranged at the cavity surface. The second heating element may be arranged at the cavity surface.

In some embodiments, the planar cavity surface comprises a first planar cavity surface and a second planar cavity surface. The second planar cavity surface is opposite the first planar cavity surface. The first planar cavity surface extends substantially in a plane. The second planar cavity surface extends in a plane. Preferably the plane of the second cavity surface is parallel to the plane of the first cavity surface. The distance between the first cavity surface and the second cavity surface may define a width of the heating cavity. In some of these embodiments, the first plane and the plane of the first cavity surface are coplanar. In other words, in some embodiments the first plane and the plane of the first cavity surface are the same plane. The first planar heating element may extend in the plane of the first cavity surface. In some of these embodiments, the second plane and the plane of the second cavity surface are coplanar. In other words, in some embodiments the second plane and the plane of the second cavity surface are the same plane. The second planar heating element may extend in the plane of the second cavity surface.

The first heating element may be arranged at the first cavity surface. The second heating element may be arranged at the second cavity surface. The first heating element and the second heating element may be arranged at opposite sides of the heating cavity. The first heating element and the second heating element may be arranged opposite each other. In these embodiments, when an aerosol-forming substrate is arranged in the heating cavity, the aerosol-forming substrate may be arranged between the first heating element and the second heating element.

Advantageously, arranging the first heating element and the second heating element at opposite sides of the heating cavity such than when an aerosol-forming substrate is arranged in the heating cavity the aerosol-forming substrate is arranged between the first heating element and the second heating element may provide a compact device that enables particularly efficient heat transfer from the heating assemblies to an aerosol-forming substrate in the heating cavity.

According to the disclosure there is provided an aerosol-generating device. The aerosol-generating device may comprise: a heating cavity configured to receive an aerosolforming substrate. The heating cavity may be defined at one side by a planar cavity surface extending substantially in a plane. The aerosol-generating device may comprise a first heating assembly comprising a planar first heating element extending substantially in a first plane. The first plane may be parallel to the plane of the cavity surface. The first heating element may be arranged at or around a first portion of the cavity surface or forming the first portion of the cavity surface. The aerosol-generating device may comprise a second heating assembly comprising a planar second heating element extending substantially in a second plane. The second plane may be parallel to the plane of the cavity surface. The second heating element may be arranged at or around a second portion of the cavity surface or forming the second portion of the cavity surface.

According to the disclosure, there is provided an aerosol-generating device comprising: a heating cavity configured to receive an aerosol-forming substrate, the heating cavity being defined at one side by a planar cavity surface extending substantially in a plane. The aerosolgenerating device further comprises a first heating assembly and a second heating assembly. The first heating assembly comprises a planar first heating element extending substantially in a first plane parallel to the plane of the cavity surface, the first heating element being arranged at or around a first portion of the cavity surface or forming the first portion of the cavity surface. The second heating assembly comprises a planar second heating element extending substantially in a second plane parallel to the plane of the cavity surface, the second heating element being arranged at or around a second portion of the cavity surface or forming the second portion of the cavity surface.

In some preferred embodiments, the first planar heating element and the second planar heating element are arranged at the cavity surface. In some embodiments, the first planar heating element and the second planar heating element extend in the plane of the cavity surface. Advantageously, an aerosol-generating device with two heating assemblies, each heating assembly having a planar cavity surface and a planar heating element extending in the plane of the cavity surface and being arranged at or around the cavity surface may provide a compact device that enables different aerosol-forming substrates to be heated either independently or simultaneously. Providing an aerosol-generating device with two heating assemblies, each heating assembly having a planar cavity surface and a planar heating element extending in the plane of the cavity surface and being arranged at or around the cavity surface may also enable a user to accurately control the generation of aerosol from multiple substrates. Providing an aerosol-generating device with heating assemblies having a planar cavity surface and a planar heating element extending in the plane of the cavity surface and being arranged at or around the cavity surface may also ensure efficient heat transfer from the heating assemblies to aerosol-forming substrate in the heating cavity.

According to the disclosure there is provided an aerosol-generating device. The aerosol-generating device may comprise: a heating cavity configured to receive an aerosolforming substrate. The heating cavity may be defined at one side by a first planar cavity surface extending substantially in a plane and at an opposite side by a second planar cavity surface extending substantially in a plane. The aerosol-generating device may comprise a first heating assembly comprising a planar first heating element extending substantially in a first plane. The first plane may be parallel to the plane of the first cavity surface. The first heating element may be arranged at the first cavity surface or form a portion of the first cavity surface. The aerosolgenerating device may comprise a second heating assembly comprising a planar second heating element extending substantially in a second plane. The second plane may be parallel to the plane of the second cavity surface. The second heating element may be arranged at the second cavity surface or form a portion of the second cavity surface.

According to the disclosure there is provided an aerosol-generating device. The aerosol-generating device comprises: a heating cavity configured to receive an aerosol-forming substrate, the heating cavity being defined at one side by a first planar cavity surface extending substantially in a plane and at an opposite side by a second planar cavity surface extending substantially in a plane. The aerosol-generating device further comprises a first heating assembly comprising a planar first heating element extending substantially in a first plane. The first plane is parallel to the plane of the first cavity surface. The first heating element is arranged at the first cavity surface or forms a portion of the first cavity surface. The aerosolgenerating device further comprises a second heating assembly comprising a planar second heating element extending substantially in a second plane. The second plane is parallel to the plane of the second cavity surface. The second heating element is arranged at the second cavity surface or forms a portion of the second cavity surface. In some preferred embodiments, the first planar heating element and the second planar heating element are arranged opposite each other, at opposite sides of the heating cavity. In some embodiments, the first planar heating element extends in the plane of the first cavity surface and the second planar heating element extends in the plane of the second cavity surface.

As used herein, “planar” refers to a feature generally formed in a single Euclidean plane and not wrapped around or otherwise conformed to fit a curved or other non-planar shape. A planar surface extends in two dimensions in a single Euclidean plane. A planar object extends in two dimensions in a single Euclidean plane substantially more than in a third dimension parallel to the plane. More specifically, a planar object extends in a first dimension and a second dimension perpendicular to the first dimension at least two, five or ten times further than the object extends in a third dimension perpendicular to the first and second dimensions. Advantageously, planar components of a heating assembly may be easily handled during manufacture and provide for a robust construction.

The aerosol-generating device may be a flat aerosol-generating device. The first heating assembly may be a flat heating assembly. The first heating element may be a flat heating element. The second heating assembly may be a flat heating assembly. The second heating element may be a flat heating element.

As used herein, “flat” refers to a substantially two dimensional topological manifold. In other words, “flat” means substantially two-dimensional. An example of a flat object is a structure between two substantially parallel surfaces, wherein the distance between the two surfaces is substantially smaller than the extension within the surfaces. A flat feature extends in two dimensions substantially more than in a third dimension. More specifically, a flat feature extends in a first dimension and a second dimension perpendicular to the first dimension at least five times further than the feature extends in a third dimension perpendicular to the first and second dimensions. A substantially flat feature may be planar. A substantially flat feature may be curved along one or more dimensions, for example forming a dome shape or bridge shape. Advantageously, a flat aerosol-generating device may provide for a robust construction that is easily handled and stored by a user. Advantageously, flat components of a heating assembly may be easily handled during manufacture and provide for a robust construction.

The aerosol-generating device may be a flat, planar aerosol-generating device. The first heating assembly may be a flat, planar heating assembly. The first heating element may be a flat, planar heating element. The second heating assembly may be a flat, planar heating assembly. The second heating element may be a flat, planar heating element.

As used herein, “aerosol-generating device” refers to a device that interacts with an aero-sol-forming substrate to generate an aerosol. As used herein, “aerosol-forming substrate” refers to a substrate capable of releasing volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. An aerosol-forming substrate is typically part of an aerosol-generating article.

As used herein, “aerosol-generating article” refers to an article comprising an aerosolforming substrate that is capable of releasing volatile compounds that can form an aero-sol. For example, an aerosol-generating article may be an article that generates an aero-sol that is directly inhalable by the user drawing or puffing on a mouthpiece at a proximal or mouth end of the aerosol-generating article, an aerosol-generating device, or an aero-sol-generating system. An aerosol-generating article may be disposable.

As used herein, “aerosol-generating system” refers to the combination of an aerosolgenerating device with an aerosol-generating article. In an aerosol-generating system, the aerosol-generating article and the aerosol-generating device cooperate to generate an aerosol.

As used herein, “proximal” refers to a user end, or mouth end of the aerosol-generating device, aerosol-generating article, or aerosol-generating system. The proximal end of a component of an aerosol-generating device, an aerosol-generating article, or an aerosolgenerating system is the end of the component closest to the user end, or mouth end of the aerosol-generating device, the aerosol-generating article, or the aerosol-generating system. As used herein, “distal” refers to the end opposite the proximal end.

As used herein, “end” and “side” are used interchangeably to refer to extremities of a feature, such as an aerosol-generating device, a heating assembly, a heating element, or an aerosol-generating article. Preferably, features described herein have two opposing ends and at least one side extending between the two opposing ends. Preferably, features described herein have a length extending in a longitudinal direction between opposing ends, and a width extending in a transverse direction between two opposing sides.

As used herein, “length” refers to the maximum dimension of a feature in a longitudinal direction of the feature.

As used herein, “width” refers to the maximum dimension of a feature in a transverse direction of the feature. The transverse direction is perpendicular to the longitudinal direction.

As used herein, “thickness” and “depth” refer to the maximum dimension of a feature in a direction perpendicular to the longitudinal direction of the feature and perpendicular to the transverse direction of the feature.

The aerosol-generating device may comprise a controller. The controller may comprise a microprocessor, which may be a programmable microprocessor, a microcontroller, or an application specific integrated chip (ASIC) or other electronic circuitry capable of providing control. The controller may comprise further electronic components. The controller may be configured to control a supply of power to the first heating assembly to heat the first heating element.

The controller may be configured to control a supply of power to the second heating assembly to heat the second heating element.

The controller may be configured to selectively control the supply of power to the first heating assembly and selectively control the supply of power to the second heating assembly. The aerosol-generating device may comprise a user interface. The user interface may have a first user input configured to enable a user to selectively control the supply of power to the first heating assembly. The user interface may have a second user input configured to enable a user to selectively control the supply of power to the second heating assembly.

The user interface may be any suitable user interface. The user interface may comprise one or more physical user inputs, such as buttons or switches. The user interface may comprise a touch screen. Where the user interface comprises a touch screen, the one or more user inputs may be portions of the touch screen.

Advantageously, enabling selective control of the supply of power to the first heating assembly and selective control of the supply of power to the second heating assembly may provide a user with improved control over the aerosol generated by the aerosol-generating device from an aerosol-forming substrate received in the heating cavity.

The controller may be configured to control the supply of power to the first heating assembly to heat the first heating element to a first operating temperature.

The controller may be configured to control the supply of power to the second heating assembly to heat the second heating element to a second operating temperature. In some embodiments, the second operating temperature is the same as the first operating temperature. In some preferred embodiments, the second operating temperature is different to the first operating temperature.

As used herein, an “operating temperature” is a temperature at which volatile compounds are released from an aerosol-forming substrate.

The controller may be configured to control the supply of power to the first heating assembly to heat the first heating element to a first operating temperature of at least about 100 degrees Celsius, or at least about 200 degrees Celsius, or at least about 300 degrees Celsius. The controller may be configured to control the supply of power to the first heating assembly to heat the first heating element to a first operating temperature of no more than about 350 degrees Celsius, or no more than about 280 degrees Celsius. The controller may be configured to control the supply of power to the first heating assembly to heat the first heating element to a first operating temperature of between about 100 degrees Celsius and about 350 degrees Celsius, or between about 200 degrees Celsius and about 280 degrees Celsius. The controller may be configured to control the supply of power to the second heating assembly to heat the second heating element to a second operating temperature of at least about 100 degrees Celsius, or at least about 200 degrees Celsius, or at least about 300 degrees Celsius. The controller may be configured to control the supply of power to the second heating assembly to heat the second heating element to a second operating temperature of no more than about 350 degrees Celsius, or no more than about 280 degrees Celsius. The controller may be configured to control the supply of power to the second heating assembly to heat the second heating element to a second operating temperature of between about 100 degrees Celsius and about 350 degrees Celsius, or between about 200 degrees Celsius and about 280 degrees Celsius.

The controller may be configured to control the supply of power to the second heating assembly independent of the supply of power to the first heating assembly.

Advantageously, controlling the supply of power to the second heating assembly independent of the supply of power to the first heating assembly may enable improved control over the aerosol generated by the aerosol-generating device from an aerosol-forming substrate received in the heating cavity. Particularly advantageously, controlling the supply of power to the second heating assembly independent of the supply of power to the first heating assembly may enable a first aerosol-forming substrate arranged in the heating cavity at or around the first portion of the cavity surface to be heated independently of a second aerosol-forming substrate arranged in the heating cavity at or around the second portion of the cavity surface.

The controller may be configured to control the supply of power to the first heating assembly and the supply of power to the second heating assembly such that power is supplied to the first heating assembly and the second heating assembly simultaneously.

The controller may be configured to control the supply of power to the first heating assembly and the supply of power to the second heating assembly such that power is supplied to the first heating assembly and the second heating assembly such that power is supplied to the first heating assembly only. The controller may be configured to control the supply of power to the first heating assembly and the supply of power to the second heating assembly such that power is supplied to the first heating assembly and the second heating assembly such that power is supplied to the second heating assembly only.

The aerosol-generating device may comprise an aerosol-forming substrate detector.

In some preferred embodiments, the cavity surface is a first cavity surface, and the heating cavity is further defined at a second cavity surface, opposite the first cavity surface. The aerosol-forming substrate detector may be arranged at or around the second cavity surface.

The controller may be configured to control the supply of power to the first heating assembly based on a signal received from the aerosol-forming substrate detector. The controller may be configured to control the supply of power to the second heating assembly based on a signal received from the aerosol-forming substrate detector.

Advantageously, controlling the supply of power to the first and second heating assemblies based on a signal received from an aerosol-forming substrate detector may enable the controller to adjust the temperature to which the aerosol-forming substrate is heated based on at least one of the type and the composition of the aerosol-forming substrate to optimise aerosol generation from the aerosol-forming substrate.

The aerosol-forming substrate detector may be any suitable type of detector. For example, the aerosol-forming substrate detector may be a camera. The aerosol-forming substrate detector may be an optical sensor. The aerosol-forming substrate detector may be a barcode reader.

In some embodiments, the aerosol-forming substrate detector may be configured to detect at least one of the type and composition of the aerosol-forming substrate. In some embodiments, the aerosol-forming substrate detector may be configured to detect an identifier, such as a barcode or a QR code, associated with the aerosol-forming substrate. The identifier contains information about at least one of the type and composition of the aerosol-forming substrate. In some preferred embodiments, the aerosol-forming substrate is provided in an aerosol-generating article, and the aerosol-generating article may comprise the identifier.

In some embodiments, the aerosol-generating device comprises a first aerosol-forming substrate detector and a second aerosol-forming substrate detector. The first aerosol-forming substrate detector may be arranged at or around a first portion of the cavity surface. The second aerosol-forming substrate detector may be arranged at or around a second portion of the cavity surface.

Where the cavity surface is a first cavity surface, and the heating cavity is further defined at a second cavity surface, a first aerosol-forming substrate detector may be arranged at or around a first portion of the second cavity surface, opposite the first portion of the first cavity surface, and a second aerosol-forming substrate detector may be arranged at or around a second portion of the second cavity surface, opposite the second portion of the first cavity surface.

The controller may be configured to control the supply of power to the first heating assembly based on a signal received from the first aerosol-forming substrate detector. The controller may be configured to control the supply of power to the second heating assembly based on a signal received from the second aerosol-forming substrate detector.

Advantageously, separately controlling the supply of power to the first heating assembly based on a signal received from a first aerosol-forming substrate detector and controlling the supply of power to the second heating assembly based on a signal received from a second aerosol-forming substrate detector may enable the controller to adjust the temperature to which each of the first and second aerosol-forming substrates are heated independently of each other, optimising aerosol generation from each of the first and second aerosol-forming substrates.

In some embodiments, the second heating element is substantially identical to first heating element.

In some embodiments, the second heating element is different to the first heating element.

The first heating element may have a first heating element shape. The second heating element may have a second heating element shape. The second heating element shape may be substantially the same as the first heating element shape. The second heating element shape may be different to the first heating element shape.

The first heating element shape may be any suitable shape. The first heating element shape may be one of circular, elliptical, polygonal, square, or preferably rectangular.

The second heating element shape may be any suitable shape. The second heating element shape may be one of circular, elliptical, polygonal, square, or preferably rectangular.

The first heating element may have a first heating element size. The second heating element may have a second heating element size. The second heating element size may be substantially the same as the first heating element size. The second heating element size may be different to the first heating element size.

The first heating element has a first heating element length. The first heating element length may be any suitable length. The first heating element length may be between about 15 millimetres and about 20 millimetres.

The second heating element has a second heating element length. The second heating element length may be any suitable length. The second heating element length may be between about 15 millimetres and about 20 millimetres.

The first heating element has a first heating element width. The first heating element width may be any suitable width. The first heating element width may be between about 10 millimetres and about 15 millimetres.

The second heating element has a second heating element width. The second heating element width may be any suitable width. The second heating element width may be between about 10 millimetres and about 15 millimetres.

The first heating element has a first heating element thickness. The first heating element thickness may be any suitable thickness. The first heating element thickness may be between about 0.1 millimetres and about 0.5 millimetres.

The second heating element has a second heating element thickness. The second heating element thickness may be any suitable thickness. The second heating element thickness may be between about 0.1 millimetres and about 0.5 millimetres. The first heating element and the second heating element may be made from any suitable materials. The first heating element and the second heating element may be formed from the same material. The second heating element may be formed from a different material to first heating element.

The first heating element may be formed from an electrically conductive material. The second heating element may be formed from an electrically conductive material.

As used herein, “electrically conductive” refers to a material having a volume resistivity at 20 degrees Celsius (°C) of less than about 1 x 10^-5 ohm-metres (Qm), typically between about 1 x 10^-5 ohm-metres (Qm) and about 1 x 10^-9 ohm-metres (Qm)

The first heating element may be formed from a thermally conductive material. The second heating element may be formed from a thermally conductive material.

As used herein, “thermally conductive” refers to a material having a bulk thermal conductivity of at least about 10 Watts per metre Kelvin (mW/(m K)) at 23 degrees Celsius (°C) and a relative humidity of 50 percent as measured using the modified transient plane source (MTPS) method.

The first heating element may be formed from at least one of: graphite, molybdenum, silicon carbide, a metal, stainless steel, niobium, aluminium, nickel, titanium, and composites of metallic materials.

The second heating element may be formed from at least one of: graphite, molybdenum, silicon carbide, a metal, stainless steel, niobium, aluminium, nickel, titanium, and composites of metallic materials.

The first heating assembly may be any suitable type of heating assembly. The first heating element may be any suitable type of heating element.

The first heating assembly may be a resistive heating assembly. In some embodiments, the first heating element is a resistive heating element.

The second heating assembly may be any suitable type of heating assembly. The second heating element may be any suitable type of heating element.

The second heating assembly may be a resistive heating assembly. In some embodiments, the second heating element is a resistive heating element.

In some embodiments, the first heating assembly is an inductive heating assembly.

The first heating assembly may comprise a first inductor coil. The first inductor coil may have any suitable form. The first inductor coil may be a tubular first inductor coil. The first inductor coil may be a planar first inductor coil extending substantially in the first plane parallel to the plane of the cavity surface. The first inductor coil may be a flat inductor coil. Preferably, the first inductor coil may be a flat, planar inductor coil. The first inductor coil has a first inductor coil shape. The first inductor coil shape may be any suitable shape. The first inductor coil may have one of a circular shape, an elliptical shape, a polygonal shape, a square shape, or preferably a rectangular shape.

As used herein a “planar inductor coil” refers to a coil that generally lies on a single Euclidean plane, wherein the axis of winding of the coil is normal to the plane on which the coil lies. A planar inductor coil can have any desired shape within the plane of the coil. For example, a planar indication coil may have a circular shape or preferably may have a generally oblong or rectangular shape. Preferably, the inductor coil is a spiral coil. Particularly preferably, the inductor coil is a planar, rectangular, spiral coil.

The first inductor coil has a first inductor coil size. The first inductor coil size may be any suitable size. The first inductor coil has a first inductor coil length. The first inductor coil length may be any suitable length. The first inductor coil length may be between about 15 millimetres and about 20 millimetres. The first inductor coil has a first inductor coil width. The first inductor coil width may be any suitable width. The first inductor coil width may be between about 10 millimetres and about 15 millimetres. The first inductor coil has a first inductor coil thickness. The first inductor coil thickness may be any suitable thickness. The first inductor coil thickness may be between about 0.1 millimetres and about 0.5 millimetres.

The first inductor coil may have any suitable number of turns.

The first inductor coil may be formed from any suitable material. The first inductor coil may be formed from at least one of: silver, gold, aluminium, brass, zinc, iron, nickel, and alloys of thereof, and electrically conductive ceramics, such as yttrium-doped zirconia, indium tin oxide, and yttrium doped titanate.

The first inductor coil shape may be different to the first heating element shape. In some preferred embodiments, the first inductor coil shape is substantially the same as the first heating element shape.

The first inductor coil size may be different to the first heating element size. In some preferred embodiments, the first inductor coil size is substantially the same as the first heating element size.

Preferably, the first heating element may be arranged between the cavity surface and the first inductor coil.

The first inductor coil may generate a first varying magnetic field when a first varying current is supplied to the first inductor coil.

As used herein, “varying current” refers to a current that varies with time. An inductor coil generates a varying magnetic field when a varying electric current is supplied to the inductor coil. The term “varying current” is intended to include alternating currents. Where the varying current is an alternating current, the alternating current generates an alternating magnetic field. The varying current may be an alternating current. As used herein, “alternating current” refers to a current that periodically reverses direction. The alternating current may have any suitable frequency. Suitable frequencies for the alternating current may be between 100 kilohertz (kHz) and 30 megahertz (MHz). Where the at least one inductor coil is a tubular inductor coil, the alternating current may have a frequency of between 500 kilohertz (kHz) and 30 megahertz (MHz). Where the at least one inductor coil is a flat coil, the alternating current may have a frequency of be-tween 100 kilohertz (kHz), and 1 megahertz (MHz).

The planar first heating element may be a planar first susceptor element.

As used herein, “susceptor “ refers to an element that is heatable by penetration with a varying magnetic field. A susceptor is typically heatable by at least one of Joule heating through induction of eddy currents in the susceptor element, and hysteresis losses.

Where the first heating assembly comprises a first inductor coil, and the first heating element is a first susceptor element, the first susceptor element may be arranged to be penetrated by the first varying magnetic field generated by the first inductor coil when the first varying current is supplied to the first inductor coil.

The first susceptor element may be formed from any suitable material. Preferably, the first susceptor element comprises a magnetic material that is heatable by penetration with a varying magnetic field. The magnetic material may be a ferromagnetic material, such as ferrite, ferritic iron, a ferromagnetic alloy, a ferromagnetic steel, or a ferromagnetic stainless steel such as SAE 400 series stainless steels, SAE type 409, 410, 420 or 430 stainless steels.

As used herein, “magnetic material” refers to a material which is able to interact with a magnetic field, including both paramagnetic and ferromagnetic materials.

In some preferred embodiments, the first susceptor element comprises at least about 5 percent, or at least about 20 percent, or at least about 50 percent, or at least about 90 percent of ferromagnetic or paramagnetic materials on a dry weight basis.

The first susceptor element shape may be different to the first inductor coil shape. Preferably, the first susceptor element shape is substantially the same as the first inductor coil shape.

The first inductor coil size may be different to the first inductor coil size. Preferably, the first susceptor element size is substantially the same as the first inductor coil size.

In some embodiments, the second heating assembly is an inductive heating assembly.

The second heating assembly may comprise a second inductor coil. The second inductor coil may have any suitable form. The second inductor coil may be a tubular second inductor coil. The second inductor coil may be a planar second inductor coil extending substantially in the second plane parallel to the plane of the cavity surface. The second inductor coil may be a flat inductor coil. Preferably, the second inductor coil may be a flat, planar inductor coil. The second inductor coil has a second inductor coil shape. The second inductor coil shape may be any suitable shape. The second inductor coil may have one of a circular shape, an elliptical shape, a polygonal shape, a square shape, or preferably a rectangular shape.

The second inductor coil has a second inductor coil size. The second inductor coil size may be any suitable size. The second inductor coil has a second inductor coil length. The second inductor coil length may be any suitable length. The second inductor coil length may be between about 15 millimetres and about 20 millimetres. The second inductor coil has a second inductor coil width. The second inductor coil width may be any suitable width. The second inductor coil width may be between about 10 millimetres and about 15 millimetres. The second inductor coil has a second inductor coil thickness. The second inductor coil thickness may be any suitable thickness. The second inductor coil thickness may be between about 0.1 millimetres and about 0.5 millimetres.

The second inductor coil may have any suitable number of turns.

The second inductor coil may be formed from any suitable material. The second inductor coil may be formed from at least one of: silver, gold, aluminium, brass, zinc, iron, nickel, and alloys of thereof, and electrically conductive ceramics, such as yttrium-doped zirconia, indium tin oxide, and yttrium doped titanate.

The second inductor coil shape may be different to the second heating element shape. In some preferred embodiments, the second inductor coil shape is substantially the same as the second heating element shape.

The second inductor coil size may be different to the second heating element size. In some preferred embodiments, the second inductor coil size is substantially the same as the second heating element size.

Preferably, the second heating element may be arranged between the cavity surface and the second inductor coil.

The second inductor coil may generate a second varying magnetic field when a second varying current is supplied to the second inductor coil.

The planar second heating element may be a planar second susceptor element.

Where the second heating assembly comprises a second inductor coil, and the second heating element is a second susceptor element, the second susceptor element may be arranged to be penetrated by the second varying magnetic field generated by the second inductor coil when the second varying current is supplied to the second inductor coil.

The second susceptor element may be formed from any suitable material. Preferably, the second susceptor element comprises a magnetic material that is heatable by penetration with a varying magnetic field. The magnetic material may be a ferromagnetic material, such as ferrite, ferritic iron, a ferromagnetic alloy, a ferromagnetic steel, or a ferromagnetic stainless steel such as SAE 400 series stainless steels, SAE type 409, 410, 420 or 430 stainless steels. In some preferred embodiments, the second susceptor element comprises at least about 5 percent, or at least about 20 percent, or at least about 50 percent, or at least about 90 percent of ferromagnetic or paramagnetic materials on a dry weight basis.

The second susceptor element shape may be different to the second inductor coil shape. Preferably, the second susceptor element shape is substantially the same as the second inductor coil shape.

The second inductor coil size may be different to the second inductor coil size. Preferably, the second susceptor element size is substantially the same as the second inductor coil size.

In some embodiments, the first heating assembly is an inductive heating assembly and the second heating assembly is an inductive heating assembly. In some embodiments, the first heating assembly is a resistive heating assembly and the second heating assembly is a resistive heating assembly. In some embodiments, the first heating assembly is an inductive heating assembly and the second heating assembly is a resistive heating assembly. In some embodiments, the first heating assembly is a resistive heating assembly and the second heating assembly is an inductive heating assembly.

The first heating assembly may further comprise a first shielding element.

The first shielding element may be a planar first shielding element extending substantially in the first plane parallel to the plane of the cavity surface. The first shielding element may be a flat first shielding element. The first shielding element may be a flat, planar shielding element.

The first shielding element may be arranged in any suitable location. Preferably, the first heating element is arranged between the cavity surface and the first shielding element. Where the first heating assembly comprises a first inductor coil, a first heating element, and a first shielding element, the first inductor coil may be arranged between the first heating element and the first shielding element.

The first shielding element has a first shielding element shape. The first shielding element shape may be any suitable shape. The first shielding element shape may be different to the first heating element shape. Preferably, the first shielding element shape is substantially the same as the first heating element shape. The first shielding element may have one of a circular shape, an elliptical shape, a polygonal shape, a square shape, or preferably a rectangular shape.

The first shielding element has a first shielding element size. The first shielding element size may be any suitable size. The first shielding element size may be different to the first heating element size. Preferably, the first shielding element size is substantially the same as the first heating element size. The first shielding element has a first shielding element length. The first shielding element length may be any suitable length. The first in shielding element length may be between about 15 millimetres and about 20 millimetres. The first shielding element has a first shielding element width. The first shielding element width may be any suitable width. The first shielding element width may be between about 10 millimetres and about 15 millimetres. The first shielding element has a first shielding element thickness. The first shielding element thickness may be any suitable thickness. The first shielding element thickness may be between about 0.1 millimetres and about 0.5 millimetres.

The first shielding element may be formed from any suitable material.

The first shielding element may be formed from an electrically conductive material. The first shielding element may comprise a metal or a metal alloy. The first shielding element may comprise one or more of: copper, nickel, silver, a silver-aluminium alloy, a silver-copper alloy, silver-glass fibre, and a nickel-graphite alloy. The first shielding element may comprise a copper alloy. The first shielding element may comprise Nickel Silver. In other words, the first shielding element may comprise an alloy of copper, nickel and zinc. The first shielding element may comprise copper alloy 770. The first shielding element may comprise an alloy comprising 55 percent by weight of copper, 27 percent by weight of zinc, and 18 percent by weight of nickel.

The first shielding element may comprise silicon. The first shielding element may comprise a silicon substrate including metal particles. The metal particles may comprise one or more of: copper, nickel, silver, a silver-aluminium alloy, a silver-copper alloy, silver-glass fibre, and a nickel-graphite alloy.

The first shielding element may be formed from a material having a relative magnetic permeability of at least 5, or at least 10, or at least 20, or at least 30, or at least 40, or at least 50, or at least 60, or at least 80, or at least 100 for a frequency of between 6 and 8 megahertz (MHz) and a temperature of 25 degrees Celsius. Advantageously, providing a first shielding element with such a relative magnetic permeability may enable the shielding element to shield one or more of the outside of the device and other components of the device from any varying magnetic fields generated by the first heating assembly.

The first shielding element may comprises a magnetic material. The first shielding element may comprise at least about 5 percent, or at least about 20 percent, or at least about 50 percent, or at least about 90 percent of ferromagnetic or paramagnetic materials on a dry weight basis. The magnetic material of the first shielding element may be a ferromagnetic material, such as ferrite, ferritic iron, a ferromagnetic alloy, a ferromagnetic steel, or a ferromagnetic stainless steel such as SAE 400 series stainless steels, SAE type 409, 410, 420 or 430 stainless steels. Advantageously, forming the first shielding element from a magnetic material may enable the shielding element to shielding one or more of the outside of the device and other components of the device from any varying magnetic fields generated by the first heating assembly. The first shielding element may comprise a fabric. The first shielding element may comprise a fabric comprising polyester. The first shielding element may comprise an EMF fabric, sometimes referred to as a Faraday Fabric. Suitable commercially available Faraday Fabrics include: Faraday Fabric commercially available from NEWBEAU, which comprises 20 precent by weight copper and nickel and 80 percent by weight polyester; and Faraday Fabric commercially available from COVA, which comprises 20 percent by weight copper and nickel and 80 percent by weight polyester. Other suitable Faraday Fabrics include TitanRF Faraday Fabric commercially available from Mission Darkness, which comprises 62 ± 7 percent by weight polyester fibres, 25 ± 7 percent by weight copper, and 13 ± 7 percent by weight nickel; and Protection Fabric commercially available from Amradield, which comprises polyester, nickel and copper.

The first shielding element may comprise a laminar structure. In other words, the first shielding element may comprise a multi-layered composition of different elements. Each element or layer may be a thin foil. The laminar structure may comprise at least one of a layer comprising an electrically conductive material, a layer comprising a magnetic material, a layer comprising a thermally insulative material and a layer comprising an electrically insulative material.

As used herein, “thermally insulative” refers to a material having a bulk thermal conductivity of less than about 5 Watts per metre Kelvin (mW/(m K)) at 23 degrees Celsius (°C) and a relative humidity of 50 percent as measured using the modified transient plane source (MTPS) method.

As used herein, “electrically insulative” refers to a material having a volume resistivity at 20 degrees Celsius (°C) of greater than about 1 x 10⁶ ohm-metres (Qm), typically between about 1 x 10⁹ ohm-metres (Qm) and about 1 x 10²¹ ohm-metres (Qm).

The second heating assembly may further comprise a second shielding element.

The second shielding element may be a planar second shielding element extending substantially in the second plane parallel to the plane of the cavity surface. The second shielding element may be a flat second shielding element. The second shielding element may be a flat, planar shielding element.

The second shielding element may be arranged in any suitable location. Preferably, the second heating element is arranged between the cavity surface and the second shielding element. Where the second heating assembly comprises a second inductor coil, a second heating element, and a second shielding element, the second inductor coil may be arranged between the second heating element and the second shielding element.

The second shielding element has a second shielding element shape. The second shielding element shape may be any suitable shape. The second shielding element shape may be different to the second heating element shape. Preferably, the second shielding element shape is substantially the same as the second heating element shape. The second shielding element may have one of a circular shape, an elliptical shape, a polygonal shape, a square shape, or preferably a rectangular shape.

The second shielding element has a second shielding element size. The second shielding element size may be any suitable size. The second shielding element size may be different to the second heating element size. Preferably, the second shielding element size is substantially the same as the second heating element size. The second shielding element has a second shielding element length. The second shielding element length may be any suitable length. The second in shielding element length may be between about 15 millimetres and about 20 millimetres. The second shielding element has a second shielding element width. The second shielding element width may be any suitable width. The second shielding element width may be between about 10 millimetres and about 15 millimetres. The second shielding element has a second shielding element thickness. The second shielding element thickness may be any suitable thickness. The second shielding element thickness may be between about 0.1 millimetres and about 0.5 millimetres.

The second shielding element may be formed from any suitable material.

The second shielding element may be formed from an electrically conductive material. The second shielding element may comprise a metal or a metal alloy. The second shielding element may comprise one or more of: copper, nickel, silver, a silver-aluminium alloy, a silvercopper alloy, silver-glass fibre, and a nickel-graphite alloy. The second shielding element may comprise a copper alloy. The second shielding element may comprise Nickel Silver. In other words, the second shielding element may comprise an alloy of copper, nickel and zinc. The second shielding element may comprise copper alloy 770. The second shielding element may comprise an alloy comprising 55 percent by weight of copper, 27 percent by weight of zinc, and 18 percent by weight of nickel.

The second shielding element may comprise silicon. The second shielding element may comprise a silicon substrate including metal particles. The metal particles may comprise one or more of: copper, nickel, silver, a silver-aluminium alloy, a silver-copper alloy, silver-glass fibre, and a nickel-graphite alloy.

The second shielding element may be formed from a material having a relative magnetic permeability of at least 5, or at least 10, or at least 20, or at least 30, or at least 40, or at least 50, or at least 60, or at least 80, or at least 100 for a frequency of between 6 and 8 megahertz (MHz) and a temperature of 25 degrees Celsius. Advantageously, providing a second shielding element with such a relative magnetic permeability may enable the shielding element to shield one or more of the outside of the device and other components of the device from any varying magnetic fields generated by the second heating assembly. The second shielding element may comprises a magnetic material. The second shielding element may comprise at least about 5 percent, or at least about 20 percent, or at least about 50 percent, or at least about 90 percent of ferromagnetic or paramagnetic materials on a dry weight basis. The magnetic material of the second shielding element may be a ferromagnetic material, such as ferrite, ferritic iron, a ferromagnetic alloy, a ferromagnetic steel, or a ferromagnetic stainless steel such as SAE 400 series stainless steels, SAE type 409, 410, 420 or 430 stainless steels. Advantageously, forming the second shielding element from a magnetic material may enable the shielding element to shielding one or more of the outside of the device and other components of the device from any varying magnetic fields generated by the second heating assembly.

The second shielding element may comprise a fabric. The second shielding element may comprise a fabric comprising polyester. The second shielding element may comprise an EMF fabric, sometimes referred to as a Faraday Fabric. Suitable commercially available Faraday Fabrics include: Faraday Fabric commercially available from NEWBEAU, which comprises 20 precent by weight copper and nickel and 80 percent by weight polyester; and Faraday Fabric commercially available from COVA, which comprises 20 percent by weight copper and nickel and 80 percent by weight polyester. Other suitable Faraday Fabrics include TitanRF Faraday Fabric commercially available from Mission Darkness, which comprises 62 ± 7 percent by weight polyester fibres, 25 ± 7 percent by weight copper, and 13 ± 7 percent by weight nickel; and Protection Fabric commercially available from Amradield, which comprises polyester, nickel and copper.

The second shielding element may comprise a laminar structure. In other words, the second shielding element may comprise a multi-layered composition of different elements. Each element or layer may be a thin foil. The laminar structure may comprise at least one of a layer comprising an electrically conductive material, a layer comprising a magnetic material, a layer comprising a thermally insulative material and a layer comprising an electrically insulative material.

The heating cavity is configured to receive an aerosol-forming substrate. Where the aerosol-forming substrate is comprised in an aerosol-generating article, the heating cavity may be configured to receive at least a portion of an aerosol-generating article. The heating cavity may be configured to receive a first aerosol-forming substrate and a second aerosol-forming substrate. Where the first aerosol-forming substrate and the second aerosol-forming substrate are comprised in an aerosol-generating article, the heating cavity may be configured to receive the aerosol-generating article.

The heating cavity may have any suitable form.

The second portion of the cavity surface may be adjacent to the first portion of the cavity surface. The second portion of the cavity surface may be spaced from the first portion of the cavity surface.

The heating cavity has a transverse cross-sectional shape. The transverse cross- sectional shape of the heating cavity may have any suitable shape. The transverse cross- sectional shape of the heating cavity may be one of circular, elliptical, polygonal, square, or preferably rectangular.

As used herein, a “transverse cross-section” is a cross-section of a feature taken perpendicular to the longitudinal direction of the feature.

The heating cavity has a heating cavity length. The heating cavity length may be any suitable length. The heating cavity length may be between about 45 millimetres and about 55 millimetres.

The heating cavity has a heating cavity width. The heating cavity width may be any suitable width. The heating cavity width may be between about 10 millimetres and about 15 millimetres.

The heating cavity has a heating cavity depth. The heating cavity depth may be any suitable depth. The heating cavity depth may be between about 0.10 millimetres and about 7 millimetres.

The heating cavity has a proximal end and a distal end. Preferably, the proximal end of the heating cavity is open for receiving the aerosol-forming substrate. Preferably, distal end of the heating cavity is substantially closed. In some preferred embodiments, the first heating assembly is arranged towards the proximal end of the heating cavity, and the second heating assembly is arranged towards the distal end of the heating cavity.

In some embodiments, the first heating assembly is arranged at or towards the proximal end of the heating cavity, and the second heating assembly is arranged at or towards the distal end of the heating cavity. In some of these embodiments, the controller may be configured to supply power to the first heating assembly to heat the first heating element before supplying power to the second heating assembly to heat the second heating element. Advantageously, supplying power to the first heating assembly at the proximal end of the heating cavity to heat the first heating element before supplying power to the second heating assembly to heat the second heating element may ensure that the aerosol-forming substrate in the heating cavity that is to be heated by the second heating assembly is not heated by vapour generated by the aerosol-forming substrate that is heated by the first heating assembly as it is drawn through the aerosol-generating article.

The aerosol-generating device may comprise at least one air inlet. The at least one air inlet may be arranged to enable ambient air to enter the aerosol-generating device. The at least one air inlet may enable ambient air to enter the heating cavity. The at least one air inlet may be arranged at an outer surface of the aerosol-generating device. The at least one air inlet may be arranged at any suitable location in the aerosol-generating device. The at least one air inlet may be arranged at or towards a proximal end of the aerosol-generating device.

The aerosol-generating device may comprise at least one air outlet. The at least one air outlet may be arranged at the heating cavity. The at least one air outlet may be arranged at any suitable location in the heating cavity. The at least one air outlet may be arranged at or towards a distal end of the heating cavity.

The aerosol-generating device may comprise an airflow path extending between the at least one air inlet and the at least one air outlet. As used herein, the terms “airflow path”, “air path”, “airflow passage” and “air passage” are used interchangeably to refer to a path through the aerosol-generating system or a part of the system along which air flows during use of the aerosol-generating system. The airflow path may be configured to enable ambient air to flow from the air inlet through the airflow path and out of the air outlet into the heating cavity. The airflow path may comprise one or more bends. The airflow path may be tortuous. Providing the aerosol-generating device with an airflow path, and particularly a tortuous airflow path, may enable the resistance to draw of the aerosol-generating system to be accurately controlled.

In some embodiments, the aerosol-generating device may comprises a mouthpiece. The mouthpiece may comprise a mouthpiece opening. The mouthpiece opening may extend to the heating cavity, The mouthpiece opening may be configured to enable air to be drawn out of the heating cavity, The mouthpiece may be arranged at a proximal end of the aerosol- generating device, The mouthpiece opening may be arranged at a proximal end of the aerosol- generating device.

The mouthpiece may be couplable to the housing of the aerosol-generating device. The mouthpiece may be removable from the housing of the aerosol-generating device. The mouthpiece may be movably coupled to the housing of the aerosol-generating device. The mouthpiece may be hingedly coupled to the housing of the aerosol-generating device.

The mouthpiece may define a proximal end of the heating cavity.

The mouthpiece may be formed from any suitable material. The mouthpiece may be formed from any material that is suitable for the housing of the aerosol-generating device. In some preferred embodiments, the mouthpiece is formed from the same material as the housing of the aerosol-generating device. In some embodiments, the aerosol-generating device comprises a heater frame. The heater frame the heater frame may define a portion of the heating cavity. The heater frame may define the heater cavity. The heater frame may provide a structure onto which at least one of the heating elements and the heating assemblies may be mounted. The provision of a heater frame onto which the heating elements and heating assemblies may be mounted may facilitate manufacture and maintenance of the aerosol-generating device.

A heating element may be mounted to an external surface of the heater frame. A heating assembly may be mounted to an external surface of the heater frame. A heating element may be mounted to an internal surface of the heater frame. A heating assembly may be mounted to an internal surface of the heater frame.

The heater frame may be formed from any suitable material. In particular, the heater frame may be formed from any material that is suitable for the housing of the aerosol-generating device. The heater frame may be formed from the same material as the housing of the aerosolgenerating device. In some embodiments, the heater frame 35 may be formed from a material having a high thermal conductivity. This may improve heat transfer from the heating assemblies to the aerosol-generating article, in particular where heating elements are mounted to external surfaces of the heater frame. For example, the heater frame may be formed from aluminium. Where the heater frame is formed from an electrically conductive material, it may be necessary to electrically insulate the heating elements and the heating assemblies from the heater frame.

The aerosol-generating device may have any suitable form. The aerosol-generating device may be planar, extending in a plane. The plane of the aerosol-generating device may be parallel to the plane of the cavity surface. The aerosol-generating device may be flat. The aerosol-generating device may be a flat, planar aerosol-generating device.

The aerosol-generating device may be elongate.

As used herein, an “elongate” feature refers to a feature having a length that is substantially greater than the other dimensions of the feature. For example, an elongate feature may have a length that is at least three times longer than the other dimensions of the feature.

The aerosol-generating device has a transverse cross-sectional shape. The aerosolgenerating device may have any suitable transverse cross-sectional shape. In some embodiments, the transverse cross-sectional shape of the aerosol-generating device is rectangular or square.

The aerosol-generating device may have two planar opposing outer surfaces, extending in planes parallel to the plane of the cavity surface. The two planar opposing outer surface may have any suitable shape. The two planar opposing outer surfaces may have a substantially rectangular or square shape.

The aerosol-generating device may have any suitable size. Preferably, the aerosolgenerating device is portable. The aerosol-generating device may be a handheld aerosol- generating device. In other words, the aerosol-generating device may be sized and shaped to be held in the hand of a user. The aerosol-generating device may have a size comparable to a conventional cigar or cigarette. The aerosol-generating device may have a length of between approximately 70 millimetres and approximately 120 millimetres.

The aerosol-generating device has an aerosol-generating device length. The aerosolgenerating device length may be any suitable length. The aerosol-generating device length may be between about 30 millimetres and about 150 millimetres, between about 70 millimetres and about 120 millimetres, or preferably between about 100 millimetres and about 110 millimetres.

The aerosol-generating device has an aerosol-generating device width. The aerosolgenerating device width may be any suitable width. The aerosol-generating device width may be between about 25 millimetres and about 35 millimetres.

The aerosol-generating device has an aerosol-generating device thickness. The aerosol-generating device thickness may be any suitable thickness. The aerosol-generating device thickness may be between about 20 millimetres and about 30 millimetres.

The aerosol-generating device may comprise a housing. The housing may define at least a portion of the heating cavity.

The housing may be planar, extending in a plane. The plane of the housing may be parallel to the plane of the cavity surface. Preferably, the housing is flat. The housing may be a planar, flat housing.

The housing may comprise any suitable material or combination of materials.

The housing may be formed from a non-magnetic material.

As used herein, “non-magnetic material” refers to a material which does not interact with a magnetic field, and is not heatable by penetration with an alternating magnetic field.

In some embodiments, the housing is formed from an electrically insulative material.

Preferably, the material is light and non-brittle.

Examples of suitable materials include metals, alloys, plastics or composite materials containing one or more of those materials, or thermoplastics that are suitable for food or pharmaceutical applications, for example polypropylene, polyetheretherketone (PEEK) and polyethylene.

The aerosol-generating device may comprise a power supply. The power supply may be arranged to supply power to the first heating assembly. The power supply may be arranged to supply power to the second heating assembly.

The power supply may be any suitable power supply. Preferably, the power supply is a DC power supply. The power supply may be a battery. The power supply may be a rechargeable battery. The battery may be a Lithium based battery, for example a Lithium-Cobalt, a Lithium- Iron-Phosphate, a Lithium Titanate, or a Lithium-Polymer battery. The battery may be a Nickel- metal hydride battery or a Nickel cadmium battery. The power supply may be another form of charge storage device such as a capacitor. The power supply may be rechargeable and be configured for many cycles of charge and discharge. The power supply may have a capacity that allows for the storage of enough energy for one or more user experiences of the aerosolgenerating system; for example, the power supply may have sufficient capacity to allow for the continuous generation of aerosol for a period of around six minutes, corresponding to the typical time taken to smoke a conventional cigarette, or for a period that is a multiple of six minutes. In another example, the power supply may have sufficient capacity to allow for a predetermined number of puffs or discrete activations of the first heating assembly and the second heating assembly. The power supply may be configured to supply between about 5 puffs and about 12 puffs on the aerosol-generating device. The power supply may be configured to supply between about 8 puffs and about 10 puffs on the aerosol-generating device.

The aerosol-generating device comprises a controller, and may comprise further electronic components. For example, in some embodiments, the controller may comprise any of: sensors, switches, and display elements.

Where at least one of the first heating assembly and the second heating assembly is an inductive heating assembly, and where the power supply is a DC power supply, the aerosolgenerating device may comprise a DC/ AC converter. The DC/AC converter may be arranged between the DC power supply and the inductor coil of the inductive heating assembly. The DC/AC converter may comprise a capacitor. The DC/AC converter may comprise a LC (inductor capacitor) load network.

In some preferred embodiments, the DC/AC converter may comprise a capacitor, wherein the DC/AC converter further comprises a LC (inductor capacitor) load network, and wherein the LC load network comprises the inductor coil and the capacitor. In some of these preferred embodiments, the inductor coil is connected in series with the capacitor.

In some preferred embodiments, the DC/AC converter comprises a Class-E power amplifier. The DC/AC converter may comprise a Class-D power amplifier. In some of these embodiments, the power supply circuit may further comprise a DC/DC converter. The DC/DC converter may be arranged between the DC power supply and the DC/AC converter. The DC/DC converter may enable DC power supplies with different supply voltages to be used with the aerosol-generating device without altering the functioning of the aerosol-generating device.

The power supply circuit may further comprise a puff detector. The puff detector may be configured to detect when a user draws on the aerosol-generating device. The puff detector may be any suitable sensor that is capable of detecting when a user draws on the aerosolgenerating device. For example, the puff detector may be an airflow sensor.

Where the power supply circuit comprises a puff detector, the controller may be configured to supply power to one or both of the first heating assembly and the second heating assembly to heat aerosol-forming substrate received in the heating cavity when the puff detector detects a user drawing or puffing on the aerosol-generating device.

According to this disclosure there is also provided an aerosol-generating system comprising: an aerosol-generating device as described above; and an aerosol-forming substrate.

The aerosol-generating system may be configured to deliver nicotine or cannabinoids to a user.

In some preferred embodiments, the aerosol-forming substrate comprises a first aerosolforming substrate and a second aerosol-forming substrate. The first aerosol-forming substrate may be arranged in the heating cavity at or around the first portion of the cavity surface. The second aerosol-forming substrate may be arranged in the heating cavity at or around the second portion of the cavity surface. Advantageously, arranging the first aerosol-forming substrate in the heating cavity at or around the first portion of the cavity surface, and arranging the second aerosol-forming substrate in the heating cavity at or around the second portion of the cavity surface may enable the first aerosol-forming substrate and the second aerosolforming substrate to be heated separately, and selectively, by the first heating assembly and the second heating assembly respectively.

In some embodiments, the second aerosol-forming substrate is formed from the same material as the first aerosol-forming substrate. In some embodiments, the second aerosolforming substrate is formed from a different material than the first aerosol-forming substrate.

The aerosol-generating system may comprise an aerosol-generating article comprising the aerosol-forming substrate.

The aerosol-generating article may have any suitable form. The aerosol-generating article may be planar, extending in a plane. The aerosol-generating article may be flat. The aerosol-generating article may be a flat, planar aerosol-generating article.

The aerosol-generating article may be elongate. The aerosol-generating article has a transverse cross-sectional shape. The aerosolgenerating article may have any suitable transverse cross-sectional shape. In some embodiments, the transverse cross-sectional shape of the aerosol-generating article is rectangular or square.

The aerosol-generating article may have two planar opposing outer surfaces, extending in planes parallel to the plane of the cavity surface when the article is received in the heating cavity. The two planar opposing outer surface may have any suitable shape. The two planar opposing outer surfaces may have a substantially rectangular or square shape.

The aerosol-generating article may have any suitable size. The aerosol-generating article has an article length. The article length may be any suitable article length. The article length may be between about 55 millimetres and about 65 millimetres. The aerosol-generating article has an article width. The article width may be any suitable article width. The article width may be between about 10 millimetres and about 15 millimetres. The aerosol-generating article has an article thickness. The article thickness may be any suitable article thickness. The article thickness may be between about 0.10 millimetres and about 7 millimetres.

The aerosol-generating article may comprise a housing. The housing may define a substrate cavity. The aerosol-forming substrate may be arranged in the substrate cavity.

The aerosol-generating article may comprise at least one air inlet. The at least one air inlet may be arranged to enable ambient air to enter the aerosol-generating article. The at least one air inlet may enable ambient air to enter the substrate cavity. The at least one air inlet may be arranged at an outer surface of the aerosol-generating article. The at least one air inlet may be arranged at any suitable location in the aerosol-generating article. The at least one air inlet may be arranged at or towards a distal end of the aerosol-generating article.

The aerosol-generating article may comprise at least one air outlet. The at least one air outlet may be arranged at the substrate cavity. The at least one air outlet may be arranged at any suitable location in the substrate cavity. The at least one air outlet may be arranged at or towards a distal end of the substrate cavity.

The aerosol-generating article may comprise an airflow path extending between the at least one air inlet and the at least one air outlet. The airflow path may be configured to enable ambient air to flow from the air inlet through the airflow path and out of the air outlet into the substrate cavity. The airflow path may comprise one or more bends. The airflow path may be tortuous. Providing the aerosol-generating article with an airflow path, and particularly a tortuous airflow path, may enable the resistance to draw of the aerosol-generating system to be accurately controlled.

The housing may be planar, extending in a plane. The plane of the housing may be parallel to the plane of the cavity surface. Preferably, the housing is flat. The housing may be a planar, flat housing. The aerosol-generating article housing may have a planar external surface extending in a plane. The aerosol-generating system may be configured such that when a portion of the aerosol-generating article is received in the heating cavity, the planar external surface is at or adjacent to the plane of the cavity surface. The aerosol-generating system may be configured such that when a portion of the aerosol-generating article is received in the heating cavity, the planar external surface is parallel to the plane of the cavity surface.

Advantageously, positioning the planar external surface of the aerosol-generating article at or adjacent the cavity surface, and preferably parallel to the plane of the cavity surface, may provide a compact device that enables efficient heat transfer from the heating assemblies to the aerosol-generating article. This is because the housing of the aerosol-generating article is arranged as close as possible to the heating assemblies.

The aerosol-generating article housing may have a first planar external surface extending in a plane and a second planar external surface extending in a plane. The second planar external surface may form the opposite external surface to the first planar external surface. The aerosol-generating system may be configured such that when a portion of the aerosol-generating article is received in the heating cavity, the first planar external surface is at or adjacent to the plane of the first cavity surface and the second planar external surface is at or adjacent to the plane of the second cavity surface. The aerosol-generating system may be configured such that when a portion of the aerosol-generating article is received in the heating cavity, the first planar external surface is parallel to the plane of the first cavity surface and the second planar external surface is parallel to the plane of the second cavity surface.

The housing may comprise any suitable material or combination of materials.

The housing may be formed from a non-magnetic material.

In some embodiments, the housing is formed from an electrically insulative material. In some embodiments, the housing is formed from an electrically insulative material. Preferably, the material is light and non-brittle.

Examples of suitable materials include paper, cardboard, metals, alloys, plastics or composite materials containing one or more of those materials, or thermoplastics that are suitable for food or pharmaceutical applications, for example polypropylene, polyetheretherketone (PEEK) and polyethylene.

Where the aerosol-generating system comprises a first aerosol-forming substrate and a second aerosol-forming substrate, the aerosol-generating system may comprise an aerosolgenerating article comprising the first aerosol-forming substrate and the second aerosol-forming substrate.

Where the aerosol-generating article comprises a housing defining a substrate cavity, the first aerosol-forming substrate may be arranged in the substrate cavity and the second aerosol-forming substrate may be arranged in the substrate cavity. The first aerosol-forming substrate may be spaced from the second aerosol-forming substrate. An airflow path may be provided between the first aerosol-forming substrate and the second aerosol-forming substrate. Advantageously, providing an airflow path between the first aerosol-forming substrate and the second aerosol-forming substrate may improve mixing of vapour and aerosol generated from the first aerosol-forming substrate and the second aerosolforming substrate.

The aerosol-forming substrate may be a planar aerosol-forming substrate extending in a plane. The aerosol-generating system may be configured such that the plane of the aerosolforming substrate is parallel to the plane of the cavity surface when the aerosol-forming substrate is received in the heating cavity.

The aerosol-forming substrate may be a flat aerosol-forming substrate. The aerosolforming substrate may be a flat, planar aerosol-forming substrate.

Where the aerosol-generating system comprises a first aerosol-forming substrate and a second aerosol-forming substrate, the first aerosol-forming substrate may be a planar aerosolforming substrate extending in a first plane. The aerosol-generating system may be configured such that the first plane of the aerosol-forming substrate is parallel to the first plane of the first portion of the cavity surface when the first aerosol-forming substrate is received in the heating cavity. Where the aerosol-generating system comprises a first aerosol-forming substrate and a second aerosol-forming substrate, the second aerosol-forming substrate may be a planar aerosol-forming substrate extending in a second plane. The aerosol-generating system may be configured such that the second plane of the aerosol-forming substrate is parallel to the second plane of the second portion of the cavity surface when the second aerosol-forming substrate is received in the heating cavity. The second plane of the second planar aerosol-forming substrate may be parallel to the first plane of the first planar aerosol-forming substrate. The second plane of the second planar aerosol-forming substrate may be the first plane of the first planar aerosol-forming substrate.

The aerosol-generating article may comprise an air inlet. The aerosol-generating article may comprise an air outlet. The aerosol-generating article may comprise an airflow path extending between the air inlet and the air outlet.

The airflow path in the aerosol-generating article may extend across the aerosol-forming substrate. The airflow path in the aerosol-generating article may contact the aerosol-forming substrate. The airflow path in the aerosol-generating article may extend across one or more sides of the aerosol-forming substrate.

In some embodiments, the aerosol-generating article may be configured such that the air inlet is not received in the heating cavity when the aerosol-forming substrate is received in the heating cavity. In some embodiments, the aerosol-generating article may be configured such that the air inlet is received in the heating cavity when the aerosol-forming substrate is received in the heating cavity. Where the aerosol-generating device comprises an air inlet, the air inlet of the aerosol-generating device may be aligned with the air inlet of the aerosol-generating article. Where the aerosol-generating device comprises an air outlet, the air outlet of the aerosolgenerating device may be aligned with the air inlet of the aerosol-generating article.

The aerosol-generating article may comprises a mouthpiece. The mouthpiece may comprise a mouthpiece opening. The mouthpiece opening may extend to the substrate cavity. The mouthpiece opening may be configured to enable air to be drawn out of the substrate cavity. The mouthpiece may be arranged at a proximal end of the aerosol-generating article. The mouthpiece opening may be arranged at a proximal end of the aerosol-generating article. The aerosol-generating article may be configured such that the mouthpiece is not received in the heating cavity when the aerosol-forming substrate is received in the heating cavity.

In some embodiments, the aerosol-generating article comprises a key. In some of these embodiments, the heating cavity of the aerosol-generating device is configured to receive the key when the aerosol-generating article is inserted into the heating cavity in a specific orientation.

The aerosol-generating device is configured to receive an aerosol-forming substrate. The aerosol-forming substrate may be any suitable aerosol-forming substrate.

The aerosol-forming substrate may be a solid aerosol-forming substrate. The aerosolforming substrate may be a liquid aerosol-forming substrate.

The aerosol-forming substrate may comprise tobacco. The aerosol-forming substrate may be a solid aerosol-forming substrate comprising tobacco. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds, which are released from the substrate upon heating.

The solid aerosol-forming substrate may comprise a plug of tobacco. The plug of tobacco may comprise, for example, one or more of: powder, granules, pellets, shreds, strands, strips or sheets containing one or more of: herb leaf, tobacco leaf, tobacco ribs, expanded tobacco and homogenised tobacco. As used herein, ‘homogenised tobacco material’ denotes a material formed by agglomerating particulate tobacco. Providing homogenised tobacco material may improve aerosol generation, the nicotine content and the flavour profile of the aerosol generated during heating of the aerosol-generating article. Specifically, the process of making homogenised tobacco involves grinding tobacco leaf, which more effectively enables the release of nicotine and flavours upon heating. Where the tobacco plug comprises homogenised tobacco material, the homogenised tobacco material may be in the form of a sheet. As used herein, ‘sheet’ denotes a laminar element having a width and length substantially greater than the thickness thereof. The solid aerosol-forming substrate may comprise homogenised tobacco material. The solid aerosol-forming material may comprise shreds, strands or strips of homogenised tobacco material. The solid aerosol-forming substrate may comprise a sheet of homogenised tobacco material.

Sheets of homogenised tobacco material may be formed by agglomerating particulate tobacco obtained by grinding or otherwise comminuting one or both of tobacco leaf lamina and tobacco leaf stems. Sheets of homogenised tobacco material may comprise one or more of tobacco dust, tobacco fines and other particulate tobacco by-products formed during, for example, the treating, handling and shipping of tobacco. Sheets of homogenised tobacco material are preferably formed by a casting process of the type generally comprising casting a slurry comprising particulate tobacco and one or more binders onto a conveyor belt or other support surface, drying the cast slurry to form a sheet of homogenised tobacco material and removing the sheet of homogenised tobacco material from the support surface.

The solid aerosol-forming substrate may comprises a gathered sheet of homogenised tobacco material. As used herein, ‘gathered’ is used to describe a sheet that is convoluted, folded, or otherwise compressed or constricted substantially transversely to a longitudinal axis of the aerosol-generating article.

In some preferred embodiments, the aerosol-forming substrate comprises a gathered textured sheet of homogenised tobacco material. As used herein, ‘textured sheet’ denotes a sheet that has been crimped, embossed, debossed, perforated or otherwise deformed. Use of a textured sheet of homogenised tobacco material may advantageously facilitate gathering of the sheet of homogenised tobacco material to form the aerosol-forming substrate. The aerosolforming substrate may comprise a gathered textured sheet of homogenised tobacco material comprising a plurality of spaced-apart indentations, protrusions, perforations or a combination thereof.

In a particularly preferred embodiment, the aerosol-forming substrate comprises a gathered crimped sheet of homogenised tobacco material. As used herein, ‘crimped sheet’ denotes a sheet having a plurality of substantially parallel ridges or corrugations. Preferably, the substantially parallel ridges or corrugations extend along or parallel to a longitudinal axis of the aerosol-generating article. This advantageously facilitates gathering of the crimped sheet of homogenised tobacco material to form the aerosol-generating article. However, it will be appreciated that crimped sheets of homogenised tobacco material for inclusion in the aerosolgenerating article may alternatively or in addition have a plurality of substantially parallel ridges or corrugations that are disposed at an acute or obtuse angle to the longitudinal axis of the aerosol-generating article.

The aerosol-forming substrate may comprise tobacco-containing material and nontobacco containing material. The aerosol-forming substrate may comprise an aerosol former. The aerosol-forming substrate may comprise a single aerosol former or a combination of two or more aerosol formers. As used herein, the term ‘aerosol former’ is used to describe any suitable known compound or mixture of compounds that, in use, facilitates formation of an aerosol and that is substantially resistant to thermal degradation at the operating temperature of the aerosolgenerating article. Suitable aerosol-formers include, but are not limited to: polyhydric alcohols, such as propylene glycol, triethylene glycol, 1 ,3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dod ecaned io ate and dimethyl tetradecanedioate. Preferred aerosol formers are polyhydric alcohols or mixtures thereof, such as propylene glycol, triethylene glycol, 1 ,3-butanediol and, most preferred, glycerine. The aerosol-forming substrate may have an aerosol former content of greater than 5 percent on a dry weight basis. The aerosol aerosol-forming substrate may have an aerosol former content of between approximately 5 percent and approximately 30 percent on a dry weight basis. The aerosolforming substrate may have an aerosol former content of approximately 20 percent on a dry weight basis.

The aerosol-forming substrate preferably comprises homogenised tobacco material, an aerosol-former and water.

The homogenised tobacco material may be provided in sheets, which are one of folded, crimped, or cut into strips. In a particularly preferred embodiment, the sheets are cut into strips having a width of between about 0.2 millimetres and about 2 millimetres, more preferably between about 0.4 millimetres and about 1 .2 millimetres. In one embodiment, the width of the strips is about 0.9 millimetres.

In some embodiments, the aerosol-forming substrate is a gel. Advantageously, the gel is solid at room temperature. As used herein, a “solid gel” refers to a gel that has a stable size and shape and does not flow at room temperature. As used herein, “room temperature” refers to 25 degrees Celsius.

Where the aerosol-forming substrate is a gel, advantageously the gel may be a thermoreversible gel. This means that the gel will become fluid when heated to a melting temperature and will set into a gel again at a gelation temperature. The gelation temperature is preferably at or above room temperature and atmospheric pressure. Atmospheric pressure means a pressure of 1 atmosphere. The melting temperature is preferably higher than the gelation temperature. Preferably the melting temperature of the gel is above 50 degrees Celsius, or 60 degrees Celsius or 70 degrees Celsius and more preferably above 80 degrees Celsius. The melting temperature in this context means the temperature at which the gel is no longer solid and begins to flow. The gel may comprise a gelling agent. Preferably, the gel comprises agar or agarose or sodium alginate. The gel may comprise Gellan gum. The gel may comprise a mixture of materials. The gel may comprise water.

The gel may be provided as a single block or may be provided as a plurality of gel elements, for example beads or capsules. The use of capsules or beads may allow a user to see when a cartridge has already been used because gel will not form the same capsules or beads on gelation after heating and subsequent cooling.

The gel may comprise nicotine or a tobacco product or another target compound for delivery to a user. When the resulting aerosol is to contain nicotine, it is advantageous for the nicotine to be contained in the gel or in another solid form in the substrate container rather than in a liquid. The nicotine can be included in the gel with an aerosol-former. Nicotine is irritating to the skin and can be toxic. Preventing any possible leakage of nicotine by locking the nicotine into a gel at room temperature is therefore desirable.

When agar is used as the gelling agent, the gel preferably comprises between 0.5 and 5% by weight (and more preferably between 0.8 and1 % by weight) agar. The gel may further comprise between 0.1 and 2% by weight nicotine. The gel may further comprise between 30% and 90% by weight (and more preferably between 70 and 90% by weight) glycerin. A remainder of the gel may comprise water and any flavourings.

When Gellan gum is used as the gelling agent, the gel preferably comprises between 0.5 and 5% by weight Gellan gum. The gel may further comprise between 0.1 and 2% by weight nicotine. The gel may further comprise between 30% and 99.4% by weight gylcerin. A remainder of the gel may comprise water and any flavourings.

In one embodiment, the gel comprises 2% by weight nicotine, 70% by weight glycerol, 27% by weight water and 1 % by weight agar. In another embodiment, the gel comprises 65% by weight glycerol, 20% by weight water, 14.3% by weight tobacco and 0.7% by weight agar.

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

1 . An aerosol-generating device comprising: a heating cavity configured to receive an aerosol-forming substrate, the heating cavity being defined at one side by a planar cavity surface extending substantially in a plane; a first heating assembly comprising a planar first heating element extending substantially in a first plane parallel to the plane of the cavity surface; and a second heating assembly comprising a planar second heating element extending substantially in a second plane parallel to the plane of the cavity surface, wherein optionally the first heating element is arranged at or around a first portion of the cavity surface or forms the first portion of the cavity surface; and wherein optionally the second heating element is arranged at or around a second portion of the cavity surface or forms the second portion of the cavity surface.

2. An aerosol-generating device according to example Ex 1 , further comprising a controller.

3. An aerosol-generating device according to example Ex2, wherein the controller is configured to control a supply of power to the first heating assembly to heat the first heating element, and wherein the controller is configured to control a supply of power to the second heating assembly to heat the second heating element, and optionally wherein the aerosolgenerating device comprises a user interface having a first user input configured to enable a user to selectively control the supply of power to the first heating assembly, and a second user input configured to enable a user to selectively control the supply of power to the second heating assembly.

4. An aerosol-generating device according to example Ex3, wherein the controller is configured to control the supply of power to the first heating assembly to heat the first heating element to a first operating temperature, and wherein the controller is configured to control the supply of power to the second heating assembly to heat the second heating element to a second operating temperature, the second operating temperature being different to the first operating temperature.

5. An aerosol-generating device according to example Ex3 or Ex4, wherein the controller is configured to control the supply of power to the first heating assembly to heat the first heating element to a first operating temperature of at least about 100 degrees Celsius, or at least about 200 degrees Celsius, or no more than about 350 degrees Celsius, or no more than about 280 degrees Celsius, or between about 100 degrees Celsius and about 350 degrees Celsius, or between about 200 degrees Celsius and about 280 degrees Celsius.

6. An aerosol-generating device according to any one of examples Ex3 to Ex5, wherein the controller is configured to control the supply of power to the second heating assembly to heat the second heating element to a second operating temperature of at least about 100 degrees Celsius, or at least about 200 degrees Celsius, or no more than about 350 degrees Celsius, or no more than about 280 degrees Celsius, or between about 100 degrees Celsius and about 350 degrees Celsius, or between about 200 degrees Celsius and about 280 degrees Celsius.

7. An aerosol-generating device according to any one of examples Ex3 to Ex6, wherein the controller is configured to control the supply of power to the second heating assembly independent of the supply of power to the first heating assembly.

8. An aerosol-generating device according to any one of examples Ex3 to Ex7, wherein the controller is configured to control the supply of power to the first heating assembly and the supply of power to the second heating assembly such that power is supplied to the first heating assembly and the second heating assembly simultaneously, or such that power is supplied to the first heating assembly only, or such that power is supplied to the second heating assembly only.

9. An aerosol-generating device according to any one of examples Ex1 to Ex8, further comprising an aerosol-forming substrate detector.

10. An aerosol-generating device according to any one of examples Ex1 to Ex9, wherein: the cavity surface is a first cavity surface; the heating cavity is further defined at a second cavity surface, opposite the first cavity surface; a first aerosol-forming substrate detector is arranged at or around a first portion of the second cavity surface, opposite the first portion of the first cavity surface; and a second aerosol-forming substrate detector is arranged at or around a second portion of the second cavity surface, opposite the second portion of the first cavity surface.

11. An aerosol-generating device according to any one of examples Ex3 to Ex8, further comprising an aerosol-forming substrate detector.

12. An aerosol-generating device according to example Ex11 , wherein the controller is configured to control the supply of power to the first heating assembly based on a signal received from the aerosol-forming substrate detector, and wherein the controller is configured to control the supply of power to the second heating assembly based on a signal received from the aerosol-forming substrate detector.

13. An aerosol-generating device according to any one of examples Ex3 to Ex8, wherein: the cavity surface is a first cavity surface; the heating cavity is further defined at a second cavity surface, opposite the first cavity surface; a first aerosol-forming substrate detector is arranged at or around a first portion of the second cavity surface, opposite the first portion of the first cavity surface; and a second aerosol-forming substrate detector is arranged at or around a second portion of the second cavity surface, opposite the second portion of the first cavity surface.

14. An aerosol-generating device according to example Ex13, wherein the controller is configured to control the supply of power to the first heating assembly based on a signal received from the first aerosol-forming substrate detector, and wherein the controller is configured to control the supply of power to the second heating assembly based on a signal received from the second aerosol-forming substrate detector.

15. An aerosol-generating device according to any one of examples Ex1 to Ex14, wherein the second heating element is substantially identical to first heating element. 16. An aerosol-generating device according to any one of examples Ex1 to Ex15, wherein the first heating element has a first heating element shape, the second heating element has a second heating element shape, and the second heating element shape is substantially the same as the first heating element shape.

17. An aerosol-generating device according to any one of examples Ex1 to Ex14, wherein the first heating element has a first heating element shape, the second heating element has a second heating element shape, and the second heating element shape is different to the first heating element shape.

18. An aerosol-generating device according to examples Ex16 or Ex17, wherein the first heating element shape is one of circular, elliptical, polygonal, square, or preferably rectangular.

19. An aerosol-generating device according to any one of examples Ex16 to Ex18, wherein the second heating element shape is one of circular, elliptical, polygonal, square, or preferably rectangular.

20. An aerosol-generating device according to any one of examples Ex1 to Ex19, wherein the first heating element has a first heating element size, the second heating element has a second heating element size, and the second heating element size is substantially the same as the first heating element size.

21 . An aerosol-generating device according to any one of examples Ex1 to Ex14 or Ex16 to Ex19, wherein the first heating element has a first heating element size, the second heating element has a second heating element size, and the second heating element size is different to the first heating element size.

22. An aerosol-generating device according to any one of examples Ex1 to Ex21 , wherein the first heating element has a first heating element length, and wherein the first heating element length is between about 15 millimetres and about 20 millimetres.

23. An aerosol-generating device according to any one of examples Ex1 to Ex22, wherein the first heating element has a first heating element width, and wherein the first heating element width is between about 10 millimetres and about 15 millimetres.

24. An aerosol-generating device according to any one of examples Ex1 to Ex23, wherein the first heating element has a first heating element thickness, and wherein the first heating element thickness is between about 0.1 millimetres and about 0.5 millimetres.

25. An aerosol-generating device according to any one of examples Ex1 to Ex24, wherein the second heating element has a second heating element length, and wherein the second heating element length is between about 15 millimetres and about 20 millimetres.

26. An aerosol-generating device according to any one of examples Ex1 to Ex25, wherein the second heating element has a second heating element width, and wherein the second heating element width is between about 10 millimetres and about 15 millimetres. 27. An aerosol-generating device according to any one of examples Ex1 to Ex26, wherein the second heating element has a second heating element thickness, and wherein the second heating element thickness is between about 0.1 millimetres and about 0.5 millimetres.

28. An aerosol-generating device according to any one of examples Ex1 to Ex27, wherein the first heating element and the second heating element are formed from the same material.

29. An aerosol-generating device according to any one of examples Ex1 to Ex14 or Ex16 to Ex27, wherein the second heating element is formed from a different material to first heating element.

30. An aerosol-generating device according to any one of examples Ex1 to Ex29, wherein the first heating element is formed from at least one of: graphite, molybdenum, silicon carbide, a metal, stainless steel, niobium, aluminium, nickel, titanium, and composites of metallic materials.

31 . An aerosol-generating device according to any one of examples Ex1 to Ex30, wherein the second heating element is formed from at least one of: graphite, molybdenum, silicon carbide, a metal, stainless steel, niobium, aluminium, nickel, titanium, and composites of metallic materials.

32. An aerosol-generating device according to any one of examples Ex1 to Ex31 , wherein the first heating assembly further comprises a first inductor coil.

33. An aerosol-generating device according to example Ex32, wherein the first inductor coil is a planar first inductor coil extending substantially in the first plane parallel to the plane of the cavity surface.

34. An aerosol-generating device according to examples Ex32 or Ex33, wherein the first heating element is arranged between the cavity surface and the first inductor coil.

35. An aerosol-generating device according to any one of examples Ex32 to Ex34, wherein the first inductor coil has a first inductor coil shape, the first heating element has a first heating element shape, and the first inductor coil shape is substantially the same as the first heating element shape.

36. An aerosol-generating device according to any one of examples Ex32 to Ex35, wherein the first inductor coil has one of a circular shape, an elliptical shape, a polygonal shape, a square shape, or preferably a rectangular shape.

37. An aerosol-generating device according to any one of examples Ex32 to Ex36, wherein the first inductor coil has a first inductor coil size, the first heating element has a first heating element size, and the first inductor coil size is substantially the same as the first heating element size. 38. An aerosol-generating device according to any one of examples Ex32 to Ex37, wherein the first inductor coil has a first inductor coil length, and wherein the first inductor coil length is between about 15 millimetres and about 20 millimetres.

39. An aerosol-generating device according to any one of examples Ex32 to Ex38, wherein the first inductor coil has a first inductor coil width, and wherein the first inductor coil width is between about 10 millimetres and about 15 millimetres.

40. An aerosol-generating device according to any one of examples Ex32 to Ex39, wherein the first inductor coil has a first inductor coil thickness, and wherein the first inductor coil thickness is between about 0.1 millimetres and about 0.5 millimetres.

41 . An aerosol-generating device according to any one of examples Ex32 to Ex40, wherein the first inductor coil is formed from at least one of: silver, gold, aluminium, brass, zinc, iron, nickel, and alloys of thereof, and electrically conductive ceramics, such as yttrium-doped zirconia, indium tin oxide, and yttrium doped titanate.

42. An aerosol-generating device according to any one of examples Ex32 to Ex41 , wherein the planar first heating element is a planar first susceptor element.

43. An aerosol-generating device according to example Ex42, wherein the first inductor coil generates a first varying magnetic field when a first varying current is supplied to the first inductor coil, and wherein the first susceptor element is arranged to be penetrated by the first varying magnetic field generated by the first inductor coil.

44. An aerosol-generating device according to examples Ex42 or Ex43, wherein the first susceptor element comprises a magnetic material that is heatable by penetration with a varying magnetic field, and optionally wherein the first susceptor element comprises at least about 5 percent, or at least about 20 percent, or at least about 50 percent, or at least about 90 percent of ferromagnetic or paramagnetic materials on a dry weight basis.

45. An aerosol-generating device according to example Ex44, wherein the magnetic material may be a ferromagnetic material, such as ferrite, ferritic iron, a ferromagnetic alloy, a ferromagnetic steel, or a ferromagnetic stainless steel such as SAE 400 series stainless steels, SAE type 409, 410, 420 or 430 stainless steels.

46. An aerosol-generating device according to any one of examples Ex42 to Ex45, wherein the first inductor coil has a first inductor coil shape, the first susceptor element has a first susceptor element shape, and the first susceptor element shape is substantially the same as the first inductor coil shape.

47. An aerosol-generating device according to any one of examples Ex42 to Ex46, wherein the first inductor coil has a first inductor coil size, the first susceptor element has a first susceptor element size, and the first susceptor element size is substantially the same as the first inductor coil size. 48. An aerosol-generating device according to any one of examples Ex1 to Ex41 , wherein the first heating element is a resistive heating element.

49. An aerosol-generating device according to any one of examples Ex1 to Ex48, wherein the second heating assembly further comprises a second inductor coil.

50. An aerosol-generating device according to example Ex49, wherein the second inductor coil is a planar second inductor coil extending substantially in the second parallel to the plane of the cavity surface.

51 . An aerosol-generating device according to examples Ex49 or Ex50, wherein the second heating element is arranged between the cavity surface and the second inductor coil.

52. An aerosol-generating device according to any one of examples Ex49 to Ex51 , wherein the second inductor coil has a second inductor coil shape, the second heating element has a second heating element shape, and the second inductor coil shape is substantially the same as the second heating element shape.

53. An aerosol-generating device according to any one of examples Ex49 to Ex52, wherein the second inductor coil has one of a circular shape, an elliptical shape, a polygonal shape, a square shape, or preferably a rectangular shape.

54. An aerosol-generating device according to any one of examples Ex49 to Ex53, wherein the second inductor coil has a second inductor coil size, the second heating element has a second heating element size, and the second inductor coil size is substantially the same as the second heating element size.

55. An aerosol-generating device according to any one of examples Ex49 to Ex54, wherein the second inductor coil has a second inductor coil length, and wherein the second inductor coil length is between about 15 millimetres and about 20 millimetres.

56. An aerosol-generating device according to any one of examples Ex49 to Ex55, wherein the second inductor coil has a second inductor coil width, and wherein the second inductor coil width is between about 10 millimetres and about 15 millimetres.

57. An aerosol-generating device according to any one of examples Ex49 to Ex56, wherein the second inductor coil has a second inductor coil thickness, and wherein the second inductor coil thickness is between about 0.1 millimetres and about 0.5 millimetres.

58. An aerosol-generating device according to any one of examples Ex49 to Ex57, wherein the second inductor coil is formed from at least one of: silver, gold, aluminium, brass, zinc, iron, nickel, and alloys of thereof, and electrically conductive ceramics, such as yttrium- doped zirconia, indium tin oxide, and yttrium doped titanate.

59. An aerosol-generating device according to any one of examples Ex49 to Ex58, wherein the planar second heating element is a planar second susceptor element.

60. An aerosol-generating device according to example Ex59, wherein the second inductor coil generates a second varying magnetic field when a second varying current is supplied to the second inductor coil, and wherein the second susceptor element is arranged to be penetrated by the second varying magnetic field generated by the second inductor coil.

61 . An aerosol-generating device according to examples Ex59 or Ex60, wherein the second susceptor element comprises a magnetic material that is heatable by penetration with a varying magnetic field, and optionally wherein the second susceptor element comprises at least about 5 percent, or at least about 20 percent, or at least about 50 percent, or at least about 90 percent of ferromagnetic or paramagnetic materials on a dry weight basis.

62. An aerosol-generating device according to example Ex61 , wherein the magnetic material may be a ferromagnetic material, such as ferrite, ferritic iron, a ferromagnetic alloy, a ferromagnetic steel, or a ferromagnetic stainless steel such as SAE 400 series stainless steels, SAE type 409, 410, 420 or 430 stainless steels.

63. An aerosol-generating device according to any one of examples Ex59 to Ex62, wherein the second inductor coil has a second inductor coil shape, the second susceptor element has a second susceptor element shape, and the second susceptor element shape is substantially the same as the second inductor coil shape.

64. An aerosol-generating device according to any one of examples Ex59 to Ex63, wherein the second inductor coil has a second inductor coil size, the second susceptor element has a second susceptor element size, and the second susceptor element size is substantially the same as the second inductor coil size.

65. An aerosol-generating device according to any one of examples Ex1 to Ex58, wherein the second heating element is a resistive heating element.

66. An aerosol-generating device according to any one of examples Ex1 to Ex65, wherein the first heating assembly further comprises a first shielding element.

67. An aerosol-generating device according to example Ex66, wherein the first shielding element is a planar first shielding element extending substantially in the first plane parallel to the plane of the cavity surface.

68. An aerosol-generating device according to examples Ex66 or Ex67, wherein the first heating element is arranged between the cavity surface and the first shielding element.

69. An aerosol-generating device according to any one of examples Ex66 to Ex68, wherein the first shielding element has a first shielding element shape, the first heating element has a first heating element shape, and the first shielding element shape is substantially the same as the first heating element shape.

70. An aerosol-generating device according to any one of examples Ex66 to Ex69, wherein the first shielding element has one of a circular shape, an elliptical shape, a polygonal shape, a square shape, or preferably a rectangular shape.

71 . An aerosol-generating device according to any one of examples Ex66 to Ex70, wherein the first shielding element has a first shielding element size, the first heating element has a first heating element size, and the first shielding element size is substantially the same as the first heating element size.

72. An aerosol-generating device according to any one of examples Ex66 to Ex71 , wherein the first shielding element has a first shielding element length, and wherein the first in shielding element length is between about 15 millimetres and about 20 millimetres.

73. An aerosol-generating device according to any one of examples Ex66 to Ex72, wherein the first shielding element has a first shielding element width, and wherein the first shielding element width is between about 10 millimetres and about 15 millimetres.

74. An aerosol-generating device according to any one of examples Ex66 to Ex73, wherein the first shielding element has a first shielding element thickness, and wherein the first shielding element thickness is between about 0.1 millimetres and about 0.5 millimetres.

75. An aerosol-generating device according to any one of examples Ex66 to Ex74, wherein the first shielding element is formed from a material having a relative magnetic permeability of at least 5, or at least 10, or at least 20, or at least 30, or at least 40, or at least 50, or at least 60, or at least 80, or at least 100 for a frequency of between 6 and 8 megahertz (MHz) and a temperature of 25 degrees Celsius.

76. An aerosol-generating device according to examples Ex66 to Ex75, wherein the first shielding element comprises a magnetic material, and optionally wherein the first shielding element comprises at least about 5 percent, or at least about 20 percent, or at least about 50 percent, or at least about 90 percent of ferromagnetic or paramagnetic materials on a dry weight basis.

78. An aerosol-generating device according to example Ex76, wherein the magnetic material may be a ferromagnetic material, such as ferrite, ferritic iron, a ferromagnetic alloy, a ferromagnetic steel, or a ferromagnetic stainless steel such as SAE 400 series stainless steels, SAE type 409, 410, 420 or 430 stainless steels.

79. An aerosol-generating device according to any one of examples Ex1 to Ex78, wherein the second heating assembly further comprises a second shielding element.

80. An aerosol-generating device according to example Ex79, wherein the second shielding element is a planar second shielding element extending substantially in the second plane parallel to the plane of the cavity surface.

81 . An aerosol-generating device according to examples Ex79 or Ex80, wherein the second heating element is arranged between the cavity surface and the second shielding element.

82. An aerosol-generating device according to any one of examples Ex79 to Ex81 , wherein the second shielding element has a second shielding element shape, the second heating element has a second heating element shape, and the second shielding element shape is substantially the same as the second heating element shape. 83. An aerosol-generating device according to any one of examples Ex79 to Ex82, wherein the second shielding element has one of a circular shape, an elliptical shape, a polygonal shape, a square shape, or preferably a rectangular shape.

84. An aerosol-generating device according to any one of examples Ex79 to Ex83, wherein the second shielding element has a second shielding element size, the second heating element has a second heating element size, and the second shielding element size is substantially the same as the second heating element size.

85. An aerosol-generating device according to any one of examples Ex79 to Ex84, wherein the second shielding element has a second shielding element length, and wherein the second in shielding element length is between about 15 millimetres and about 20 millimetres.

86. An aerosol-generating device according to any one of examples Ex79 to Ex85, wherein the second shielding element has a second shielding element width, and wherein the second shielding element width is between about 10 millimetres and about 15 millimetres.

87. An aerosol-generating device according to any one of examples Ex79 to Ex86, wherein the second shielding element has a second shielding element thickness, and wherein the second shielding element thickness is between about 0.1 millimetres and about 0.5 millimetres.

88. An aerosol-generating device according to any one of examples Ex79 to Ex87, wherein the second shielding element is formed from a material having a relative magnetic permeability of at least 5, or at least 10, or at least 20, or at least 30, or at least 40, or at least 50, or at least 60, or at least 80, or at least 100 for a frequency of between 6 and 8 megahertz (MHz) and a temperature of 25 degrees Celsius.

89. An aerosol-generating device according to examples Ex79 to Ex88, wherein the second shielding element comprises a magnetic material, and optionally wherein the second shielding element comprises at least about 5 percent, or at least about 20 percent, or at least about 50 percent, or at least about 90 percent of ferromagnetic or paramagnetic materials on a dry weight basis.

90. An aerosol-generating device according to example Ex89, wherein the magnetic material may be a ferromagnetic material, such as ferrite, ferritic iron, a ferromagnetic alloy, a ferromagnetic steel, or a ferromagnetic stainless steel such as SAE 400 series stainless steels, SAE type 409, 410, 420 or 430 stainless steels.

91 . An aerosol-generating device according to any one of examples Ex1 to Ex90, wherein the second portion of the cavity surface is adjacent to the first portion of the cavity surface.

92. An aerosol-generating device according to any one of examples Ex1 to Ex90, wherein the second portion of the cavity surface is spaced from the first portion of the cavity surface. 93. An aerosol-generating device according to any one of examples Ex1 to Ex92, wherein the transverse cross-sectional shape of the heating cavity is one of circular, elliptical, polygonal, square, or preferably rectangular.

94. An aerosol-generating device according to any one of examples Ex1 to Ex93, wherein the heating cavity has a heating cavity length, and wherein the heating cavity length is between about 45 millimetres and about 55 millimetres.

95. An aerosol-generating device according to any one of examples Ex1 to Ex94, wherein the heating cavity has a heating cavity width, and wherein the heating cavity width is between about 10 millimetres and about 15 millimetres.

96. An aerosol-generating device according to any one of examples Ex1 to Ex95, wherein the heating cavity has a heating cavity depth, and wherein the heating cavity dept is between about 0.10 millimetres and about 7 millimetres.

97. An aerosol-generating device according to any one of examples Ex1 to Ex96, wherein the heating cavity has a proximal end and a distal end.

98. An aerosol-generating device according to example Ex97, wherein the proximal end of the heating cavity is open for receiving the aerosol-forming substrate.

99. An aerosol-generating device according to examples Ex97 or Ex98, wherein the distal end of the heating cavity is substantially closed.

100. An aerosol-generating device according to any one of examples Ex97 to Ex99, wherein the first heating assembly is arranged towards the proximal end of the heating cavity, and the second heating assembly is arranged towards the distal end of the heating cavity.

101. An aerosol-generating device according to any one of examples Ex1 to Ex100 further comprising at least one air inlet, and optionally wherein the at least one air inlet is arranged at an outer surface of the aerosol-generating device.

102. An aerosol-generating device according to example Ex101 , wherein the at least one air inlet is arranged to enable ambient air to enter the aerosol-generating device.

103. An aerosol-generating device according to example Ex101 or Ex102 further comprising an airflow path extending between the at least one air inlet and an air outlet.

104. An aerosol-generating device according to example Ex103, wherein the air outlet is arranged at the heating cavity to enable ambient air to flow from the air inlet through the airflow path and out of the air outlet into the heating cavity, and optionally wherein the air outlet is arranged at or towards a distal end of the heating cavity.

105. An aerosol-generating device according to example Ex101 , wherein at least one of the at least one air inlet is arranged to enable ambient air to enter the heating cavity.

106. An aerosol-generating device according to any one of examples Ex101 to Ex105, wherein the at least one air inlet is arranged at or towards a proximal end of the aerosolgenerating device. 107. An aerosol-generating device according to any one of examples Ex1 to Ex106, wherein the aerosol-generating device comprises a housing, and optionally wherein the housing defines the heating cavity.

108. An aerosol-generating device according to example Ex107, wherein the housing is formed from at least one of a metal, a metal alloy, a plastic material, or a composite material containing one or more of these materials.

109. An aerosol-generating device according to any one of examples Ex1 to Ex108, wherein the aerosol-generating device has an aerosol-generating device length, and wherein the aerosol-generating device length is between about 100 millimetres and about 110 millimetres.

110. An aerosol-generating device according to any one of examples Ex1 to Ex109, wherein the aerosol-generating device has an aerosol-generating device width, and wherein the aerosol-generating device width is between about 25 millimetres and about 35 millimetres.

111. An aerosol-generating device according to any one of examples Ex1 to Ex110, wherein the aerosol-generating device has an aerosol-generating device thickness, and wherein the aerosol-generating device thickness is between about 20 millimetres and about 30 millimetres.

112. An aerosol-generating device according to any one of examples Ex1 to Ex111 further comprising a power supply arranged to supply power to the first heating assembly and the second heating assembly, and optionally wherein the power supply is a DC power supply, such as a rechargeable battery.

113. An aerosol-generating device according to example Ex112, wherein the power supply is configured to supply between about 5 puffs and about 12 puffs on the aerosolgenerating device, and optionally between about 8 puffs and about 10 puffs on the aerosolgenerating device.

114. An aerosol-generating system comprising: an aerosol-generating device according to any one of examples Ex1 and Ex113; and an aerosol-forming substrate.

115. An aerosol-generating system according to example Ex114, wherein the aerosolforming substrate comprises a first aerosol-forming substrate and a second aerosol-forming substrate.

116. An aerosol-generating system according to example Ex115, wherein the first aerosol-forming substrate is arranged in the heating cavity at or around the first portion of the cavity surface; and wherein the second aerosol-forming substrate is arranged in the heating cavity at or around the second portion of the cavity surface. 117. An aerosol-generating system according to example Ex115 or Ex116, wherein the second aerosol-forming substrate is formed of a different material than the first aerosolforming substrate.

118. An aerosol-generating system according to any one of examples Ex114 to Ex117 comprising an aerosol-generating article comprising the aerosol-forming substrate.

119. An aerosol-generating system according to any one of examples Ex115 to Ex117 comprising an aerosol-generating article comprising the first aerosol-forming substrate and the second aerosol-forming substrate.

120. An aerosol-generating system according to example Ex119, wherein the first aerosol-forming substrate is spaced from the second aerosol-forming substrate, and optionally wherein an airflow path is provided between the first aerosol-forming substrate and the second aerosol-forming substrate.

121. An aerosol-generating system according to example Ex118, wherein the aerosolforming substrate is a planar aerosol-forming substrate extending in a plane, and optionally wherein the aerosol-generating system is configured such that the plane of the aerosol-forming substrate is parallel to the plane of the cavity surface when the aerosol-forming substrate is received in the heating cavity.

122. An aerosol-generating system according to examples Ex119 or Ex120, wherein at least one of: the first aerosol-forming substrate is a planar aerosol-forming substrate extending in a first plane, and optionally wherein the aerosol-generating system is configured such that the first plane of the aerosol-forming substrate is parallel to the first plane of the first portion of the cavity surface when the first aerosol-forming substrate is received in the heating cavity; and the second aerosol-forming substrate is a planar aerosol-forming substrate extending in a second plane, and optionally wherein the aerosol-generating system is configured such that the second plane of the aerosol-forming substrate is parallel to the second plane of the second portion of the cavity surface when the second aerosolforming substrate is received in the heating cavity.

123. An aerosol-generating system according to any one of examples Ex118 to Ex122, wherein the aerosol-generating article further comprises an air inlet, an air outlet, and an airflow path extending between the air inlet and the air outlet.

124. An aerosol-generating system according to example Ex123, wherein the airflow path in the aerosol-generating article contacts the aerosol-forming substrate.

125. An aerosol-generating system according to example Ex123 or Ex124, wherein the aerosol-generating article comprises a mouthpiece, and wherein the air outlet is arranged at the mouthpiece. 126. An aerosol-generating system according to example Ex125, wherein the aerosolgenerating article is configured such that the mouthpiece is not received in the heating cavity when the aerosol-forming substrate is received in the heating cavity.

127. An aerosol-generating system according to any one of examples Ex118 to Ex126, wherein the aerosol-generating article is planar.

128. An aerosol-generating system according to any one of examples Ex118 to Ex127, wherein the aerosol-generating article has a transverse cross-sectional shape that is rectangular or square.

129. An aerosol-generating system according to any one of examples Ex118 to Ex128, wherein the aerosol-generating article has two planar opposing outer surfaces, extending in planes parallel to the plane of the cavity surface, and optionally wherein the two planar opposing outer surfaces have a substantially rectangular or square shape.

130. An aerosol-generating system according to any one of examples Ex 118 to Ex128, wherein the aerosol-generating article has an article length, and wherein the article length is between about 55 millimetres and about 65 millimetres.

131. An aerosol-generating system according to any one of examples Ex118 to Ex130, wherein the aerosol-generating article has an article width, and wherein the article width is between about 10 millimetres and about 15 millimetres

132. An aerosol-generating system according to any one of examples Ex118 to Ex131 , wherein the aerosol-generating article has an article thickness, and wherein the article thickness is between about 0.10 millimetres and about 7 millimetres.

133. An aerosol-generating system according to any one of examples Ex118 to Ex132, wherein the aerosol-generating article comprises a key, and wherein the heating cavity of the aerosol-generating device is configured to receive the key when the aerosol-generating article is inserted into the heating cavity in a specific orientation.

Examples will now be further described with reference to the figures in which:

Figure 1 shows a schematic illustration of an aerosol-generating device according to this disclosure;

Figure 2 shows a schematic illustration of a cross-sectional view of the aerosolgenerating device of Figure 1 , taken along the line A-A shown in Figure 1 ;

Figure 3 shows a schematic illustration of an exploded view of a heater assembly of the aerosol-generating device of Figure 1 ;

Figure 4 shows a schematic illustration of an exploded view of an aerosol-generating article according to this disclosure that is suitable for use with the aerosol-generating device of Figure 1 ;

Figure 5 shows a schematic illustration of the aerosol-generating article of Figure 4; Figure 6 shows a schematic illustration of an aerosol-generating system according to the disclosure, comprising the aerosol-generating device of Figure 1 and the aerosol-generating article of Figure 4;

Figure 7 shows a schematic illustration of the aerosol-generating system of Figure 6 with the aerosol-generating article received in the heating cavity of the aerosol-generating device;

Figure 8 shows a schematic illustration of an alternative aerosol-generating system according to the disclosure, comprising an aerosol-generating device and an aerosol-generating article;

Figure 9 shows a schematic illustration of the aerosol-generating system of Figure 8 with the aerosol-generating article received in the heating cavity of the aerosol-generating device;

Figure 10 shows a schematic illustration of an alternative aerosol-generating system according to the disclosure, comprising an aerosol-generating device and an aerosol-generating article;

Figure 11 shows a schematic illustration of the aerosol-generating system of Figure 10 with the aerosol-generating article received in the heating cavity of the aerosol-generating device;

Figure 12 shows an exploded view of an alternative aerosol-generating system according to the disclosure, comprising an aerosol-generating device and an aerosol-generating article;

Figure 13 shows a schematic illustration of an alternative aerosol-generating system according to the disclosure, comprising an aerosol-generating device and an aerosol-generating article; and

Figure 14 shows a schematic illustration of the aerosol-generating system of Figure 13 with the aerosol-generating article received in the heating cavity of the aerosol-generating device.

Figure 1 shows an aerosol-generating device 1 according to this disclosure. The aerosol-generating device is a generally flat, planar device, with a rectangular transverse cross- sectional shape. The aerosol-generating device has a length of 100 millimetres, a width of 25 millimetres, and a thickness of 20 millimetres.

The aerosol-generating device comprises a housing 2, formed of PEEK. The housing 2 defines a heating cavity 3. The heating cavity 3 is configured to receive an aerosol-forming substrate. As shown in Figure 2, the heating cavity 3 is defined at one side by a first planar cavity surface 4 extending substantially in a plane. The heating cavity 3 is further defined at an opposite side by a second planar cavity surface 5, extending in a plane parallel to the plane of the first planar cavity surface 4. The heating cavity 3 has a rectangular transverse crosssection. The heating cavity has a length of 50 millimetres, a width of 12 millimetres, and a depth of 4 millimetres. The heating cavity 3 has a proximal end that is substantially open to enable aerosol-forming substrate to be inserted into the heating cavity 3, and a distal end, opposite the proximal end, that is substantially closed.

The aerosol-generating device 1 further comprises a first heating assembly 6, and a second heating assembly 7. The first heating assembly 6 is arranged at a first portion 8 of the first cavity surface 4. The second heating assembly 7 is arranged at a second portion 9 of the first cavity surface 4, spaced from the first portion 8 and the first heating assembly 6.

In this embodiment, both the first heating assembly 6 and the second heating assembly 7 are substantially identical. As shown in Figure 3, each of the first heating assembly 6 and the second heating assembly 7 comprises a heating element 10, an inductor coil 11 , and a shielding element 12. Each of the first heating assembly 6 and the second heating assembly 7 comprises a laminar structure comprising the inductor coil 11 arranged between the susceptor 10 and the shielding element 12. The first heating assembly 6 and the second heating assembly 7 are substantially flat, planar assemblies.

The heating element 10 is a flat, planar heating element, extending in a plane. The heating element 10 is a susceptor element that is heatable by penetration with a varying magnetic field. In this embodiment, the susceptor element is formed from a ferromagnetic stainless steel.

The inductor coil 11 is a flat, planar inductor coil, extending in a plane parallel to the plane of the heating element 10. The inductor coil 10 is a square coil, having substantially square turns. The susceptor element 10 and the inductor coil 11 are arranged such that a varying current supplied to the inductor coil 11 generates a varying magnetic field that penetrates and heats the susceptor element 10.

The shielding element 12 is a flat, planar shielding element, extending in a plane parallel to the plane of the heating element 10. Like the heating element 10, the shielding element is also formed from a ferromagnetic stainless steel. The shielding element is intended to protect electrical components arranged behind the heating assembly from the varying magnetic field generated by the inductor coil 11 when a varying current is supplied to the inductor coil 11 . A further shielding element (not shown) comprised of a thermally insulative material may also be arranged behind the shielding element 12 to further protect components arranged behind the heating assembly from heat generated by the heating assembly.

The inductor coil 11 comprises a connection end 14 that extends out of the heating assembly for connection to a power supply.

Although in this embodiment both the first heating assembly 6 and the second heating assembly 7 are substantially identical, it will be appreciated that in other embodiments the second heating assembly 7 may differ from the first heating assembly 6. For example, in some other embodiments the second inductor coil may have a different number of turns to the first inductor coil. For example, in some embodiments the second heating element may have a different shape than the first heating element, or the second heating element may be formed from a different material than the first heating element. For example, in some embodiments one of the first heating assembly and the second heating assembly may be a resistive heating assembly comprising a resistive heating element.

The first heating element 10 of the first heating assembly 6 is arranged at the first portion 8 of the first cavity surface 4. The first planar heating element 10 of the first heating assembly 6 extends substantially in a first plane parallel to the plane of the first cavity surface 4.

The second heating element 10 of the second heating assembly 7 is arranged at the second portion 9 of the first cavity surface 4. The second planar heating element 10 of the second heating assembly 7 extends substantially in a second plane parallel to the plane of the first cavity surface 4.

The aerosol-generating device 1 further comprises power control circuitry 15 including a controller (not shown), and a power supply 16, in the form of a rechargeable battery. The first inductor coil 11 of the first heating assembly 6 is electrically connected to the power supply 16 via the power control circuitry 15. The second inductor coil 11 of the second heating assembly 6 is also electrically connected to the power supply 16 via the power control circuitry 15. The controller of the power control circuitry 15 controls the supply of power from the power supply 16 to the first inductor coil 11 of the first heating assembly 6, and controls the supply of power from the power supply 16 to the second inductor coil 11 of the second heating assembly 7.

The aerosol-generating device 1 further comprises an air inlet 17 extending through a side of the housing 2 into a side of the heating cavity 3. The air inlet 17 enables ambient air from outside of the aerosol-generating device 1 to be drawn directly into the heating cavity 3.

The aerosol-generating device 1 also comprises a first aerosol-forming substrate detector 18 and a second aerosol-forming substrate detector 19. The first aerosol-forming substrate detector 18 is an optical sensor, such as a barcode reader, arranged at the second cavity surface 5, opposite the first heating assembly 6. The first aerosol-forming substrate detector is configured to detect an identifier, such as a barcode, on an aerosol-generating article received in the heating cavity 3 opposite the first heating assembly 6. The second aerosolforming substrate detector 19 is an optical sensor, such as a barcode reader, arranged at the second cavity surface 5, opposite the second heating assembly 7. The second aerosol-forming substrate detector is configured to detect an identifier, such as a barcode, on an aerosolgenerating article received in the heating cavity 3 opposite the second heating assembly 7.

Figure 4 shows an aerosol-generating article 20 according to this disclosure that is suitable for use with the aerosol-generating device 1 of Figure 1 .

The aerosol-generating article 20 is a generally flat, planar aerosol-generating article, with a rectangular transverse cross-sectional shape. The aerosol-generating article is configured to be received in the heating cavity 3 of the aerosol-generating device 1 . The aerosol-generating article has a length of 70 millimetres, a width of 12 millimetres, and a depth of 4 millimetres.

The aerosol-generating article comprises a first aerosol-forming substrate 21 and a second aerosol-forming substrate 22. In this embodiment, the composition of the first aerosolforming substrate is different to the composition of the second aerosol-forming substrate 22. In this embodiment, the first aerosol-forming substrate 21 comprises tobacco and an aerosolformer, and the second aerosol-forming substrate 22 comprises tobacco, an aerosol-former, and a flavourant, such as menthol. It will be appreciated that the first and second aerosolforming substrates may have any suitable composition, which may not comprise tobacco. It will also be appreciated that in some embodiments the composition of the first and second aerosolforming substrates is the same.

The aerosol-generating article 20 further comprises a housing 23 defining a substrate cavity 201 in which the first aerosol-forming substrate 21 and the second aerosol-forming substrate 22 are arranged. The housing 23 of the aerosol-generating article 20 comprises a frame 231 surrounding the sides of the first and second aerosol-forming substrates 21 , 22, and a top plate 24 and a bottom plate 25 extending over opposite ends of the frame 231 . The first aerosol-forming substrate 21 is arranged towards a proximal end of the substrate cavity 201 , and the second aerosol-forming substrate is arranged towards a distal end of the substrate cavity 201 . The first and second aerosol-forming substrates 21 , 22 are spaced apart in the substrate cavity 201 such that air may flow between the first and second aerosol-forming substrates 21 , 22.

The frame 231 of the aerosol-generating article further defines an air inlet 26 that extends through a side of the frame 231 to an airflow path 27. The airflow path 27 extends in a distal direction in the article 20, alongside the substrate cavity 201 , to an air outlet 28 at the distal end of the substrate cavity 201 . As such, ambient air may be drawn into the substrate cavity 201 of the article 20 through the air inlet 26, the airflow path 27 and the air outlet 28.

The aerosol-generating article 20 further comprises a mouthpiece portion 29 at a proximal end of the article 20. The mouthpiece portion 29 of the article 20 comprises a mouthpiece opening 30 that extends to the proximal end of the substrate cavity 201 .

Figures 6 and 7 show the aerosol-generating device 1 in use with the aerosol-generating article 20.

The aerosol-generating article 20 may be received in the heating cavity 3 of the aerosolgenerating device 1 . When the aerosol-generating article 20 is received in the heating cavity 3 of the aerosol-generating device 1 , the mouthpiece portion 29 of the aerosol-generating article 20 remains outside of the heating cavity 3, such that a user may place their lips on the mouthpiece portion 29 of the aerosol-generating article 20 and puff on the aerosol-generating system to receive an aerosol. When the aerosol-generating article 20 is received in the heating cavity 3 of the aerosolgenerating device 1 , the air inlet 26 of the aerosol-generating article 20 is aligned with the air inlet 17 of the aerosol-generating device 1 . In this arrangement, an airflow path is provided between the air inlet 17 of the aerosol-generating device 1 and the mouthpiece opening 30 of the aerosol-generating article. The airflow path enables ambient air to be drawn into the aerosol-generating article by a user puffing on the mouthpiece portion 29 of the aerosolgenerating article 20.

In use, when a user puffs on the mouthpiece portion 29 of the aerosol-generating article 20, ambient air is drawn into the aerosol-generating device 1 via the air inlet 17. The ambient air is drawn directly into the heating chamber 3 and the aerosol-generating article 20 via the air inlet 26, which is aligned with the air inlet 17. The air drawn into the aerosol-generating article 20 via the air inlet 26 is drawn through the airflow path 27 and out of the air outlet 28 into the substrate cavity 201 . The air in the substrate cavity 201 is able to flow over the first aerosolforming substrate 21 and the second aerosol-forming substrate 22, and mix. As such, when both the first and second aerosol-forming substrates 21 , 22 are heated and release volatile compounds, the volatile compounds released from both the first and second aerosol-forming substrates mix in the substrate cavity 201 . The air and any volatile compounds released from the heated substrates in the substrate cavity 201 are then drawn out of the proximal end of the substrate cavity 201 into the mouthpiece portion 29, where the volatile compounds cool and condense to form an aerosol. The aerosol in the mouthpiece portion is drawn out of the aerosol-generating article 20 and delivered to the user at the mouthpiece opening 30.

When the aerosol-generating article 20 is received in the heating cavity 3, the first aerosol-forming substrate 21 is arranged at the first portion 8 of the first cavity surface 4, and the second aerosol-forming substrate 22 is arranged at the second portion 9 of the first cavity surface 4. As such, the first heating assembly 6 is arranged to heat the first aerosol-forming substrate 21 , and the second heating assembly 7 is arranged to heat the second aerosolforming substrate 22. The first heating element 10 of the first heating assembly 6 is arranged close to the first aerosol-forming substrate 21 , only separated by the housing 23 of the aerosolgenerating article 20. Accordingly, heat transfer from the first heating element 10 of the first heating assembly 6 to the first aerosol-forming substrate 21 is high. The second heating element 10 of the second heating assembly 7 is arranged close to the second aerosol-forming substrate 22, only separated by the housing 23 of the aerosol-generating article 20. Accordingly, heat transfer from the second heating element 10 of the second heating assembly 7 to the second aerosol-forming substrate 22 is high.

The aerosol-generating article 20 further comprises a first identifier (not shown), in the form of a first barcode, and a second identifier (not shown), in the form of a second barcode. The first barcode is arranged on the outer surface of the bottom plate 25 of the housing 23 of the article 20, aligned with the first aerosol-forming substrate 21 . The second barcode is arranged on the outer surface of the bottom plate 25 of the housing 23 of the article 20, aligned with the second aerosol-forming substrate 22. When the aerosol-generating article 20 is received in the heating cavity 3, the first aerosol-forming substrate detector 18 is aligned with the first barcode, and the second aerosol-forming substrate detector 19 is aligned with the second barcode.

The first barcode contains information that identifies the first aerosol-forming substrate. When the aerosol-generating article 20 is received in the heating cavity 3, the first aerosolforming substrate detector 18 detects the first barcode, and sends the information that identifies the first aerosol-forming substrate 21 to the controller of the power control circuitry 15. The controller is configured to control the power to the first induction coil 10 of the first heating assembly 6 based on the information received from the first aerosol-forming substrate detector 18. In this way, the controller is configured to adjust the temperature to which the first aerosolforming substrate 21 is heated to optimise aerosol generation for the first aerosol-forming substrate 21.

The second barcode contains information that identifies the second aerosol-forming substrate. When the aerosol-generating article 20 is received in the heating cavity 3, the second aerosol-forming substrate detector 19 detects the second barcode, and sends the information that identifies the second aerosol-forming substrate 22 to the controller of the power control circuitry 15. The controller is configured to control the power to the second induction coil 10 of the second heating assembly 7 based on the information received from the second aerosol-forming substrate detector 19. In this way, the controller is configured to adjust the temperature to which the second aerosol-forming substrate 22 is heated to optimise aerosol generation for the second aerosol-forming substrate 22.

The aerosol-generating device 1 further comprises a user interface connected to the controller of the power supply circuitry 15 that enables a user to control the generation of aerosol from the aerosol-generating system. In this embodiment, the user interface comprises a first user input 31 , in the form of a button, and a second user input 32, in the form of a button. The controller is configured to supply power to the first heating element 10 of the first heating assembly 6 when a user selects the first user input 31 . The controller is configured to supply power to the second heating element 10 of the second heating assembly 7 when a user selects the second user input 32. A user may select both the first user input 31 and the second user input 32 for power to be supplied to both the first heating assembly 6 and the second heating assembly 7 at the same time. As such, a user may control the aerosol that is generated by the aerosol-generating system. Figures 8 and 9 show another aerosol-generating system according to the disclosure. The aerosol-generating system of Figures 8 and 9 is substantially the same as the aerosolgenerating system of Figures 6 and 7, and like features are denoted by like reference numerals.

The aerosol-generating system of Figures 8 and 9 comprises an aerosol-generating device 1 and an aerosol-generating article 20.

The aerosol-generating device 1 comprises a housing 2 defining a heating chamber 3 with a first inductive heating assembly 6 arranged at a first portion 8 of a first cavity surface, and a second inductive heating assembly 7 arranged at a second portion 9 of the first cavity surface. The aerosol-generating device 1 further comprises power control circuitry 15 and a power supply 16.

The aerosol-generating article 20 comprises a first aerosol-forming substrate 21 and a second aerosol-forming substrate 22.

The aerosol-generating system of Figures 8 and 9 differs from the aerosol-generating system of Figures 6 and 7 in the configuration of the airflow path through the aerosol-generating system. In the embodiment of Figures 6 and 7 an airflow path extends primarily through the aerosol-generating article, whereas in the embodiment of Figures 8 and 9, the airflow path flows primarily through the aerosol-generating device.

The aerosol-generating device 1 of Figures 8 and 9 comprises an air inlet 17 that extends through a side of the housing 2 but does not extend directly into a side of the heating cavity 3. The air inlet 17 extends to an airflow path 33. The airflow path 33 extends in a distal direction in the device 1 , alongside the heating cavity 3, to an air outlet 34 at the distal end of the heating cavity 3.

The aerosol-generating article 20 of Figures 8 and 9 comprises an air inlet 26 at a distal end of the aerosol-generating article 20. The air inlet 26 extends directly into the substrate cavity 201.

When the aerosol-generating article 20 is received in the heating cavity 3, the air inlet 26 of the aerosol-generating article 20 aligns with the air outlet 34 of the aerosol-generating device 1 . In use, when a user draws on the mouthpiece ed 29 of the aerosol-generating article 20, air is drawn into the aerosol-generating device 1 through the air inlet 17, through the airflow path 33 and into the heating cavity 3 through the air outlet 34. Air is drawn into the aerosolgenerating article 20 from the air outlet 34 of the aerosol-generating device 1 at the air inlet 26 of the aerosol-generating article 20, through the substrate cavity 201 , and out of the aerosolgenerating article 20 at the mouthpiece opening 30.

Advantageously, providing such a tortuous airflow path through the aerosol-generating device may enable the aerosol-generating system to more accurately control the resistance to draw through the system. It will be appreciated that in some embodiments, the aerosol-generating device may not be provided with an air inlet or an airflow path, as the air inlet of the aerosol-generating article may be arranged outside of the heating cavity 3 when the aerosol-generating article is received in the heating cavity 3.

Figures 10 and 11 show another aerosol-generating system according to the disclosure. The aerosol-generating system of Figures 10 and 11 is substantially the same as the aerosolgenerating system of Figures 6 and 7, and like features are denoted by like reference numerals.

The aerosol-generating system of Figures 10 and 11 comprises an aerosol-generating device 1 and an aerosol-generating article 20.

The aerosol-generating device 1 is a generally flat, planar device, with a rectangular transverse cross-sectional shape. The aerosol-generating device 1 has a length of 100 millimetres, a width of 25 millimetres, and a thickness of 20 millimetres.

The aerosol-generating device 1 comprises a housing 2, formed of PEEK. The housing 2 defines a heating cavity 3. The heating cavity 3 is configured to receive an aerosol-forming substrate. The heating cavity 3 is defined at one side by a first planar cavity surface 4 extending substantially in a plane. The heating cavity 3 is further defined at an opposite side by a second planar cavity surface 5, extending in a plane parallel to the plane of the first planar cavity surface 4. The heating cavity 3 has a rectangular transverse cross-section. The heating cavity has a length of 50 millimetres, a width of 12 millimetres, and a depth of 4 millimetres. The heating cavity 3 has a proximal end that is substantially open to enable aerosol-forming substrate to be inserted into the heating cavity 3, and a distal end, opposite the proximal end, that is substantially closed.

The aerosol-generating device 1 further comprises a first heating assembly 6, and a second heating assembly 7. The first heating assembly 6 is arranged at the first cavity surface 4. The second heating assembly 7 is arranged at the second cavity surface 5. The second heating assembly 7 is arranged opposite the first heating assembly 6 and is spaced from the first heating assembly 6 by the width of the heating cavity 3.

In this embodiment, both the first heating assembly 6 and the second heating assembly 7 are substantially identical. Each of the first heating assembly 6 and the second heating assembly 7 comprises a planar resistive heating element. The first planar resistive heating element of the first heating assembly 6 is arranged at the first cavity surface and extends in a first plane that is parallel to the plane of the first cavity surface 4. The second planar resistive heating element of the second heating assembly 7 is arranged at the second cavity surface and extends in a second plane that is parallel to the plane of the second cavity surface 5.

The aerosol-generating device 1 further comprises power control circuitry 15 including a controller (not shown), and a power supply 16, in the form of a rechargeable battery. The first heating element of the first heating assembly 6 is electrically connected to the power supply 16 via the power control circuitry 15. The second heating element of the second heating assembly 7 is electrically connected to the power supply 16 via the power control circuitry 15. The controller of the power control circuitry 15 controls the supply of power from the power supply 16 to the first heating element of the first heating assembly 6 and controls the supply of power from the power supply 16 to the second heating element of the second heating assembly 7.

The aerosol-generating device 1 further comprises an air inlet 17 extending through a side of the housing 2 into an airflow path 33. The airflow path 33 extends in a distal direction in the device 1 , alongside the heating cavity 3, to an air outlet 34 at the distal end of the heating cavity 3. The air inlet 17, airflow path 33 and air outlet 34 enable ambient air from outside of the aerosol-generating device 1 to be drawn directly into the heating cavity 3.

The aerosol-generating article comprises an aerosol-forming substrate 21 . In this embodiment, the first aerosol-forming substrate 21 comprises tobacco and an aerosol-former.

The aerosol-generating article 20 further comprises a housing 23 defining a substrate cavity 201 in which the aerosol-forming substrate 21 is arranged.

The housing 23 of the aerosol-generating article further defines an air inlet 26 that extends through a side of the housing 23 at a distal end of the article 20 to the substrate cavity 201 . As such, ambient air may be drawn into the substrate cavity 201 of the article 20 through the air inlet 26.

The aerosol-generating article 20 further comprises a mouthpiece portion 29 at a proximal end of the article 20. The mouthpiece portion 29 of the article 20 comprises a proximal portion of the substrate cavity 201 that does not comprise the aerosol-forming substrate 21 . In the proximal portion of the substrate cavity 201 volatile compounds released from the heated aerosol-forming substrate 21 is able to cool and condense to form an aerosol. The mouthpiece portion 29 of the article 20 further comprises a mouthpiece opening 30 that extends to the proximal end of the substrate cavity 201 . The mouthpiece opening 30 enables aerosol generated in the substrate cavity 201 to be drawn out of the substrate cavity 201 .

Accordingly, an airflow path is formed through the aerosol-generating article 20 comprising the air inlet 26, the substrate cavity 201 and the air outlet 30.

Figure 11 shows the aerosol-generating device 1 in use with the aerosol-generating article 20. The aerosol-generating article 20 may be received in the heating cavity 3 of the aerosolgenerating device 1 . When the aerosol-generating article 20 is received in the heating cavity 3 of the aerosol-generating device 1 , the mouthpiece portion 29 of the aerosol-generating article 20 remains outside of the heating cavity 3, such that a user may place their lips on the mouthpiece portion 29 of the aerosol-generating article 20 and puff on the aerosol-generating system to receive an aerosol.

When the aerosol-generating article 20 is received in the heating cavity 3 of the aerosolgenerating device 1 , the air inlet 26 of the aerosol-generating article 20 is aligned with the air outlet 34 of the aerosol-generating device 1 . In this arrangement, an airflow path is provided between the air inlet 17 of the aerosol-generating device 1 and the mouthpiece opening 30 of the aerosol-generating article 20. The airflow path enables ambient air to be drawn into the aerosol-generating article 20 by a user puffing on the mouthpiece portion 29 of the aerosolgenerating article 20.

When the aerosol-generating article 20 is received in the heating cavity 3, the aerosolforming substrate 21 is arranged between the first heating element of the first heating assembly 6 and the second heating element of the second heating assembly 7. As such the first heating element and the second heating element are arranged to heat the aerosol-forming substrate 21 from opposite sides. The first heating element and the second heating element are arranged close to the aerosol-forming substrate 21 , only separated by the housing 23 of the aerosolgenerating article 20.

In use, when power is supplied from the power supply 16 to the first heating element of the first heating assembly 6 and power is supplied to the second heating element of the second heating assembly 7 for heating the aerosol-forming substrate, the control circuitry 15 supplies power to the first heating element and the second heating element simultaneously, such that the aerosol-forming substrate 21 is heated from opposite sides at the same time. This promotes even heating of the aerosol-forming substrate.

In use, when a user puffs on the mouthpiece portion 29 of the aerosol-generating article 20, ambient air is drawn into the aerosol-generating device 1 via the air inlet 17. The ambient air is drawn into the heating cavity 3 via the airflow path 33 and the air outlet 34, and is drawn into the aerosol-generating article 20 via the air inlet 26. The air drawn into the aerosolgenerating article 20 via the air inlet 26 is drawn into the substrate cavity 201 . The air in the substrate cavity 201 is able to flow over the aerosol-forming substrate 21 . As such, when the aerosol-forming substrate 21 is heated and releases volatile compounds, the volatile compounds released from the aerosol-forming substrate 21 are drawn out of the proximal end of the substrate cavity 201 into the mouthpiece portion 29, where the volatile compounds cool and condense to form an aerosol. The aerosol in the mouthpiece portion 29 is drawn out of the aerosol-generating article 20 and delivered to the user at the mouthpiece opening 30. Accordingly, an airflow path is formed through the aerosol-generating system comprising the air inlet 17, the airflow path 33, the air outlet 34, the air inlet 26, the substrate cavity 201 and the air outlet 30.

Figure 12 shows another aerosol-generating system according to the disclosure. The aerosol-generating system of Figure 12 is substantially the same as the aerosol-generating system of Figures 9 and 10, and like features are denoted by like reference numerals.

The aerosol-generating system of Figure 12 comprises an aerosol-generating device 1 , similar to the aerosol-generating device 1 of Figures 9 and 10, and an aerosol-generating article 20, identical to the aerosol-generating article 20 of Figures 9 and 10.

The aerosol-generating device 1 of Figure 12 differs from the aerosol-generating device 1 of Figures 9 and 10 in that the aerosol-generating device 1 of Figure 12 comprises a heater frame 35. The heater frame 35 comprises a frame that is received within a proximal end of the housing 2 of the aerosol-generating device. The heater frame 35 defines the heating cavity 3 and provides a structure onto which the first heating assembly 6 and the second heating assembly 7 are mounted.

The provision of a heater frame 35 onto which the heating elements and heating assemblies are mounted may facilitate manufacture and maintenance of the aerosol-generating device. In this embodiment, the first heating element of the first heating assembly 6 and the second heating element of the second heating assembly 7 are mounted to external surfaces of the heater frame 35, at opposite sides. This arrangement facilitates electrical connection of the heating assemblies to the power supply of the aerosol-generating device 1 . However, it will be appreciated that in some embodiments the heating elements may be mounted to inner surfaces of the heater frame 35, and the heating elements may define portions of surfaces of the heating cavity 3. This arrangement may improve heat transfer from the heating elements to an aerosolgenerating article received in the heating cavity 3.

The heater frame 35 may be formed from any suitable material. In this embodiment, the heater frame 35 is formed from PEEK, which is the same material as the housing 2 of the aerosol-generating device 1 . The heater frame 35 may be formed from any material suitable for the housing 2 of the aerosol-generating device 1 . In some embodiments, the heater frame 35 may be formed from a material having a high thermal conductivity. This may improve heat transfer from the heating assemblies to the aerosol-generating article, in particular where heating elements are mounted to external surfaces of the heater frame. For example, the heater frame may be formed from aluminium. Where the heater frame is formed from an electrically conductive material, it may be necessary to electrically insulate the heating elements and the heating assemblies from the heater frame.

Figures 13 and 14 show another aerosol-generating system according to the disclosure. The aerosol-generating system of Figures 13 and 14 is substantially the same as the aerosol- generating system of Figures 10 and 11 , and like features are denoted by like reference numerals.

The aerosol-generating system 1 of Figures 13 and 14 differs from the aerosolgenerating system 1 of Figures 10 and 11 in that the aerosol-generating device 1 of Figures 13 and 14 comprises a mouthpiece 36 and the aerosol-generating article 20 of Figures 13 and 14 does not comprise a mouthpiece portion.

The aerosol-generating device 1 of Figures 13 and 14 comprises a removable mouthpiece 36, which is configured to be arranged over the open proximal end of the housing 2 and substantially close the proximal end of the heating cavity 3. Although the mouthpiece 36 in this embodiment is removable from the housing 2 of the aerosol-generating device, it will be appreciated that in other embodiments the mouthpiece may be movably coupled to the housing 2 of the aerosol-generating device 1 , such as by a hinge.

The mouthpiece 36 defines a proximal end of the heating cavity 3 when the mouthpiece 36 is received on the housing 2. When the aerosol-generating article 20 is received in the heating cavity 3, the mouthpiece 36 extends over the proximal end of the aerosol-generating article 20, substantially enclosing the aerosol-generating article 20 in the heating cavity 3. When the aerosol-generating article 20 is received in the heating cavity 3 and the mouthpiece 36 is received on the housing 2, a space is provided at the proximal end of the heating cavity 3, between the proximal end of the housing 23 of the aerosol-generating article 20 and the mouthpiece 36. This space is provided to enable cooling of the volatile compounds released rom the heated aerosol-forming substrate 21 before delivery to a user. The provision of this space between the aerosol-generating article 20 and the mouthpiece 36 enables the substrate cavity 201 of the aerosol-generating article 20 to be filled with aerosol-forming substrate and may enable the substrate cavity 201 and the entire aerosol-generating article 20 to be made smaller than the aerosol-generating article 20 of Figures 10 and 11 .

The mouthpiece 36 of the aerosol-generating device 1 is formed from the same material as the housing 2 of the aerosol-generating device.

The mouthpiece 36 comprises an air outlet 37 to enable aerosol formed in the heating cavity 3 to be drawn out of the heating cavity 3 by a user drawing on the mouthpiece 36.

In use, when a user puffs on the mouthpiece 36 of the aerosol-generating device 1 , ambient air is drawn into the aerosol-generating device 1 via the air inlet 17. The ambient air is drawn into the heating cavity 3 via the airflow path 33 and the air outlet 34, and is drawn into the aerosol-generating article 20 via the air inlet 26. The air drawn into the aerosol-generating article 20 via the air inlet 26 is drawn into the substrate cavity 201 . The air in the substrate cavity 201 is able to flow over the aerosol-forming substrate 21 . When the aerosol-forming substrate 21 is heated and releases volatile compounds, the volatile compounds released from the aerosol-forming substrate 21 are drawn out of the aerosol-generating article 20 at the opening 30, into the proximal end of the heating cavity 3. The volatile compounds cool and condense to form an aerosol in the proximal end of the heating cavity 3 and the aerosol is drawn out of the proximal end of the heating cavity 3 at the air outlet 37, where the aerosol is delivered to the user. Accordingly, an airflow path is formed through the aerosol-generating system comprising the air inlet 17, the airflow path 33, the air outlet 34, the air inlet 26, the substrate cavity 201 , the air outlet 30, the proximal end of the heating cavity 3 and the air outlet 37.

For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 5 percent of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

1 . An aerosol-generating system comprising: an aerosol-generating article comprising: a housing defining a substrate cavity; and an aerosol-forming substrate arranged in the substrate cavity; and an aerosol-generating device comprising: a heating cavity configured to receive at least a portion of the aerosol-generating article, the heating cavity being defined at one side by a planar cavity surface extending substantially in a plane; a first heating assembly comprising a planar first heating element extending substantially in a first plane parallel to the plane of the cavity surface; and a second heating assembly comprising a planar second heating element extending substantially in a second plane parallel to the plane of the cavity surface.

2. An aerosol-generating system according to claim 1 , wherein the aerosol-generating article comprises an air inlet, an air outlet, and an airflow path extending between the air inlet and the air outlet.

3. An aerosol-generating system according to claim 2, wherein the airflow path is configured to enable ambient air to flow from the air inlet through the airflow path and out of the air outlet into the substrate cavity.

4. An aerosol-generating system according to any one of claims 1 , 2 or 3, wherein: the planar cavity surface comprises: a first planar cavity surface extending substantially in a plane; and a second planar cavity surface extending substantially in a plane, the second planar cavity surface being opposite the first planar cavity surface and the plane of the second cavity surface being parallel to the plane of the first cavity surface; and. the first heating element is arranged at the first cavity surface and the second heating element is arranged at the second cavity surface.

5. An aerosol-generating system according to any one of claims 1 to 3, wherein: the first heating element is arranged at or around a first portion of the cavity surface or forms the first portion of the cavity surface; and the second heating element is arranged at or around a second portion of the cavity surface or forms the second portion of the cavity surface.

6. An aerosol-generating system according to any one of claims 1 to 5, wherein the aerosol-generating device further comprises a controller, wherein the controller is configured to control a supply of power to the first heating assembly to heat the first heating element, wherein the controller is configured to control a supply of power to the second heating assembly to heat the second heating element, and wherein the supply of power to the second heating assembly is independent of the supply of power to the first heating assembly.

7. An aerosol-generating system according to claim 6, wherein the controller is further configured to control the supply of power to the first heating assembly to heat the first heating element to a first operating temperature, and wherein the controller is further configured to control the supply of power to the second heating assembly to heat the second heating element to a second operating temperature, the second operating temperature being different to the first operating temperature.

8. An aerosol-generating system according to any one of claims 1 to 7, wherein the first heating assembly further comprises a first shielding element, the first heating element being arranged between the cavity surface and the first shielding element.

9. An aerosol-generating system according to any one of claims 1 to 8, wherein the second heating assembly further comprises a second shielding element, the second heating element being arranged between the cavity surface and the second shielding element.

10. An aerosol-generating system according to any one of claims 1 to 9, wherein the first heating assembly further comprises a planar first inductor coil.

11. An aerosol-generating system according to claim 10, wherein the first heating assembly further comprises a planar first susceptor element extending in the first plane parallel to the plane of the cavity surface, the first susceptor element being arranged between the cavity surface and the first inductor coil.

12. An aerosol-generating system according to claim 11 , wherein the shape of the first susceptor element is substantially the same as the shape of the first inductor coil.

13. An aerosol-generating system according to any one of claims 1 to 9, wherein the first heating element is a resistive heating element.

14. An aerosol-generating system according to any one of claims 1 to 13, wherein the second heating assembly further comprises a planar second inductor coil.

15. An aerosol-generating system according to claim 14, wherein the second heating assembly further comprises a planar second susceptor element extending in a second plane parallel to the plane of the cavity surface, the second susceptor element being arranged between the cavity surface and the second inductor coil.

16. An aerosol-generating system according to claim 15, wherein the shape of the second susceptor element is substantially the same as the shape of the second inductor coil.

17. An aerosol-generating system according to any one of claims 1 to 13, wherein the second heating element is a resistive heating element.

18. An aerosol-generating system according to any one of claims 1 to 17, wherein the second portion of the cavity surface is one of adjacent to the first portion of the cavity surface or spaced from the first portion of the cavity surface.

19. An aerosol-generating system according to any one of claims 1 to 18, wherein: the cavity surface is a first cavity surface; the heating cavity is further defined at a second cavity surface, opposite the first cavity surface; a first aerosol-forming substrate detector is arranged at or around a first portion of the second cavity surface, opposite the first portion of the first cavity surface; and a second aerosol-forming substrate detector is arranged at or around a second portion of the second cavity surface, opposite the second portion of the first cavity surface.