Heating Apparatus for an Aerosol Generating Device

A heating apparatus for an aerosol generating device is disclosed. The heating apparatus comprises a first casing member, a second casing member, and one or more inductively heatable susceptors. The first casing member, the second casing member and the one or more inductively heatable susceptors cooperatively engage to form a tubular heating chamber for receiving at least part of an aerosol generating substrate. The one or more inductively heatable susceptors are arranged to couple the first casing member to the second casing member.

FIELD OF THE INVENTION

The present invention relates to a heating apparatus for an aerosol generating device, a method of manufacturing a heating assembly for an aerosol generating device, and an aerosol generating device. The disclosure is particularly applicable to a portable aerosol generating device, which may be self-contained and low temperature. Such devices may heat, rather than burn, tobacco or other suitable aerosol substrate materials by conduction, convection, and/or radiation, to generate an aerosol for inhalation.

BACKGROUND

The popularity and use of reduced-risk or modified-risk devices (also known as vaporisers) has grown rapidly in the past few years as an aid to assist habitual smokers wishing to quit using traditional tobacco products such as cigarettes, cigars, cigarillos, and rolling tobacco. Various devices and systems are available that heat or warm aerosolisable substances as opposed to burning tobacco in conventional tobacco products.

A commonly available reduced-risk or modified-risk device is the heated substrate aerosol generation device or heat-not-burn device. Devices of this type generate an aerosol or vapour by heating an aerosol substrate (i.e. consumable) that typically comprises moist leaf tobacco or other suitable aerosolisable material to a temperature typically in the range of 150° C. to 300° C. Heating an aerosol substrate, but not combusting or burning it, releases an aerosol that comprises the components sought by the user but not the undesirable by-products of combustion. In addition, the aerosol produced by heating the tobacco or other aerosolisable material does not typically comprise the burnt or bitter taste that may result from combustion that can be unpleasant for the user.

Currently available aerosol generating devices can use one of a number of different approaches to provide heat to the aerosol generating substrate. One such approach is to provide an aerosol generating device which employs an induction heating system. In such a device, an induction coil is provided in the device and an inductively heatable susceptor is provided to heat the aerosol generating substrate. Electrical energy is supplied to the induction coil when a user activates the device which in turn generates an alternating electromagnetic field. The susceptor couples with the electromagnetic field and generates heat which is transferred, for example by conduction, to the aerosol generating substrate and an aerosol is generated as the aerosol generating substrate is heated.

However, within such devices, the use of susceptors which are attached to the heating chamber often leads to a bulky aerosol generating device. Therefore, an object of the present invention is to provide a compact heating apparatus, which is able to efficiently heat an aerosol generating substrate.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a heating apparatus for an aerosol generating device, comprising: a first casing member; a second casing member; and one or more inductively heatable susceptors, wherein the first casing member, the second casing member and the one or more inductively heatable susceptors cooperatively engage to form a heating chamber for receiving at least part of an aerosol generating substrate.

In this way, as the inductively heatable susceptors form part of the heating chamber, rather than being attached onto or within the heating chamber, a more compact heating apparatus is provided. The inductively heatable susceptors cooperatively engage with the first casing member and the second casing member, which enables the inductively heatable susceptors to be optimally positioned for heating the aerosol generating substrate received within the heating chamber, without increasing the bulkiness of the heating apparatus.

Preferably, the one or more inductively heatable susceptors are arranged to couple the first casing member to the second casing member. In this way, the inductively heatable susceptors have a dual purpose of heating the aerosol generating substrate received within the heating chamber, whilst also ensuring the heating apparatus is structurally secure. In other words, the inductively heatable susceptors acts as fastening elements which secure the first casing member to the second casing member, which enables the inductively heatable susceptors to be integrated within the heating chamber, thereby providing a compact heating apparatus. The ease of manufacturing the heating apparatus may also be improved.

Preferably, the one or more inductively heatable susceptors engage with the first casing member and the second casing member such that the first casing member, the second casing member and the one or more inductively heatable susceptors are rotationally locked with respect to one another. In this way, the durability of the heating apparatus is further improved without adversely affecting the compactness of the heating apparatus. As aerosol generating devices are portable and may be roughly handled by a user, ensuring the heating apparatus has a high durability is particularly advantageous.

Preferably, the one or more inductively heatable susceptors are formed as elongate rods that are integrated within a wall of the heating chamber, wherein the one or more inductively heatable susceptors are spaced around the heating chamber and extend in a direction that is parallel to a longitudinal axis of the heating chamber. In this way, the inductively heatable susceptors provide a concentrated heating effect along the length of the aerosol substrate received within the heating chamber, whilst also providing a compact heating apparatus. The aerosol generating substrate is heated rapidly and uniformly by the inductively heatable susceptors spaced around the heating chamber.

Preferably, the one or more inductively heatable susceptors are formed as curved plates that are integrated within a wall of the heating chamber, wherein the one or more inductively heatable susceptors are spaced around the heating chamber and extend in direction that is parallel to a longitudinal axis of the heating chamber. In this way, the inductively heatable susceptors provide a large surface area for heating the aerosol substrate received within the heating chamber, whilst also providing a compact heating apparatus. The aerosol generating substrate is heated rapidly and uniformly by the inductively heatable susceptors spaced around the heating chamber.

Preferably, the one or more inductively heatable susceptors respectively comprise at least one inwardly extending portion that protrudes into the heating chamber to provide a reduced cross-sectional area of the heating chamber such that, in use, the aerosol generating substrate received within the heating chamber is compressed. In this way, by compressing the aerosol generating substrate, heat can be transferred more efficiently to the aerosol generating substrate and more rapid heating can be achieved, whilst at the same time maximising energy efficiency.

Preferably, the one or more inductively heatable susceptors respectively comprise at least one outwardly extending portion that protrudes out of the heating chamber to increase the mass of the one or more inductively heatable susceptors that may be inductively heated. In this way, a greater mass of inductively heatable susceptors is provided away from the centre of the heating chamber (i.e. in closer proximity to a surrounding induction coil). This improves the capability of the inductively heatable susceptors to harvest electromagnetic energy from the induction coil.

Preferably, the at least one outwardly extending portion of the one or more inductively heatable susceptors extend radially outwardly with respect to the outer circumferential edges of the first and second casing members.

Preferably, the first casing member is substantially tubular and comprises a first longitudinal end, wherein the second casing member is substantially tubular and comprises a second longitudinal end, and wherein the first casing member and the second casing member are coaxially aligned with the first longitudinal end of the first casing member adjacent to the second longitudinal end of the second casing member. In this way, a compact heating chamber is provided that is configured to receive a substantially cylindrical aerosol generating substrate. This may be advantageous as aerosol generating substrates, in the form of aerosol generating articles, are often packaged and sold in a cylindrical form.

Preferably, the first longitudinal end of the first casing member has a slotted configuration comprising one or more slots, and wherein the one or more inductively heatable susceptors are respectively located within the one or more slots. In this way, the one or more inductively heatable susceptors are provided in close proximity to the aerosol generating substrate received within the heating chamber, without increasing the bulkiness of the device. Moreover, the ease of manufacturing the heating apparatus may be improved.

Preferably, the second longitudinal end of the second casing member has a slotted configuration comprising one or more slots, wherein the one or more slots of the first longitudinal end of the first casing member align with the one or more slots of the second longitudinal end of the second casing member, and wherein the one or more inductively heatable susceptors are respectively located within and extend between each pair of aligned slots to couple the first casing member to the second casing member. In this way, the one or more inductively heatable susceptors are provided in close proximity to the aerosol generating substrate received within the heating chamber without increasing the bulkiness of the device, whilst also providing a secure fastening between the first casing member and the second casing member.

Preferably, the heating apparatus further comprises an inductively heatable susceptor ring that is disposed between the first longitudinal end of the first casing member and the second longitudinal end of the second casing member. In this way, a concentrated heating effect may be provided towards the centre of the aerosol generating substrate received within the heating chamber, whilst also providing a compact heating apparatus.

In one example, the one or more inductively heatable susceptors and the inductively heatable susceptor ring may be formed as a single component. In this way, the strength of the coupling between the first casing member and the second casing member may be further improved.

Preferably, the first longitudinal end of the first casing member and the second longitudinal end of the second casing member have complementary slotted configurations such that the first longitudinal end of the first casing member substantially engages with the second longitudinal end of the second casing member so that they are rotationally locked with respect to one another, and wherein the one or more inductively heatable susceptors are respectively located along one or more longitudinal interfaces between the complementary slotted configurations. In this way, the inductively heatable susceptors are able to securely fasten the first casing member to the second casing member whilst being located in an optimal position for heating the aerosol generating substrate received within the heating chamber.

Preferably, the first casing member and the second casing member can be combined along their length to form the heating chamber which is substantially tubular, and wherein the first casing member and the second casing member are clamped together by the one or more inductively heatable susceptors. In this way, a secure arrangement of components is provided which may be easily assembled and disassembled.

Preferably, the one or more inductively heatable susceptors are detachable from the first casing and the second casing. In this way, the inductively heatable susceptors may be removed and replaced, for instance if the material of the inductively heatable susceptors begins to degrade.

Preferably, the heating chamber is substantially tubular. In this way, the heating chamber may be configured to receive a substantially cylindrical aerosol generating substrate which may be advantageous as, often, aerosol generating substrates in the form of aerosol generating articles are packaged and sold in a cylindrical form.

Preferably, the heating apparatus further comprises an induction heating coil that surrounds the heating chamber.

Preferably, wherein the first casing and the second casing comprise a heat-resistant plastics material, preferably polyether ether ketone (PEEK).

According to a second aspect of the invention, there is provided a method of manufacturing a heating assembly, comprising the steps of: providing a first casing member; providing a second casing member; providing one or more inductively heatable susceptors; and cooperatively engaging the first casing member, the second casing member and the one or more inductively heatable susceptors to form a heating chamber for receiving at least part of an aerosol generating substrate.

According to third aspect of the invention, there is provided an aerosol generating device comprising a heating apparatus according to the first aspect.

DETAILED DESCRIPTION

The figures herein follow a numbering convention in which the first digit or digits correspond to the drawing figure number and the remaining digits identify an element or component in the drawing. Similar elements or components between different figures may be identified by the use of similar digits. For example,306may reference element “06” inFIG.3, and a similar element may be referenced as406inFIG.4. The skilled person will appreciate that the description of the properties and configuration of each element may equally apply to corresponding elements in other embodiments.

As described herein, a vapour is generally understood to refer to a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapour can be condensed to a liquid by increasing its pressure without reducing the temperature, whereas an aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. It should, however, be noted that the terms ‘aerosol’ and ‘vapour’ may be used interchangeably in this specification, particularly with regard to the form of the inhalable medium that is generated for inhalation by a user.

Referring initially toFIGS.1and2, there is shown diagrammatically an example of an aerosol generating system1. The aerosol generating system1comprises an aerosol generating device10and an aerosol generating article70for use with the device10.

The aerosol generating article70comprises an aerosol generating substrate72, such as tobacco. The aerosol generating device10is configured to heat, without burning, the aerosol generating article70to form an aerosol from the aerosol generating substrate72for inhalation by user of the device10.

The aerosol generating device10comprises a main body12housing various components of the aerosol generating device10. The main body12can have any shape that is sized to fit the components described in the various embodiments set out herein and to be comfortably held by a user unaided, in a single hand.

A first end14of the aerosol generating device10, shown towards the bottom ofFIGS.1and2, is described for convenience as a distal, bottom, base or lower end of the aerosol generating device10. A second end16of the aerosol generating device10, shown towards the top ofFIGS.1and2, is described as a proximal, top or upper end of the aerosol generating device10. During use, the user typically orients the aerosol generating device10with the first end14downward and/or in a distal position with respect to the user's mouth and the second end16upward and/or in a proximate position with respect to the user's mouth.

The aerosol generating device10comprises a heating chamber18positioned in the main body12. The heating chamber18defines an interior volume in the form of a cavity20having a substantially tubular cross-section, e.g. cylindrical, for receiving an aerosol generating article70. The heating chamber18has a longitudinal axis defining a longitudinal direction. The aerosol generating device10further comprises a power source22, for example one or more batteries which may be rechargeable, and a controller24.

The heating chamber18is open towards the second end16of the aerosol generating device10. In other words, the heating chamber18has an open end26towards the second end16of the aerosol generating device10. The heating chamber18is typically held spaced apart from the inner surface of the main body12to minimise heat transfer to the main body12. The heating chamber18typically has a closed end34opposite the open end26.

The aerosol generating device10can optionally include a sliding cover28movable transversely between a closed position (seeFIG.1) in which it covers the open end26of the heating chamber18to prevent access to the heating chamber18and an open position (seeFIG.2) in which it exposes the open end26of the heating chamber18to provide access to the heating chamber18. The sliding cover28can be biased to the closed position in some embodiments.

The heating chamber18, and specifically the cavity20, is arranged to receive a correspondingly shaped aerosol generating article70. For instance, in this example the heating chamber18is arranged to receive a generally cylindrical or rod-shaped aerosol generating article70. Thus, the heating chamber18is tubular, e.g. substantially cylindrical. However, the skilled person will appreciate that the shape of the heating chamber18may vary.

Typically, the aerosol generating article70comprises a pre-packaged aerosol generating substrate72. The aerosol generating article70is a disposable and replaceable article (also known as a “consumable”) which may, for example, contain tobacco as the aerosol generating substrate72. The aerosol generating article70has a proximal end74(or mouth end) and a distal end76. The aerosol generating article70further comprises a mouthpiece segment78positioned downstream of the aerosol generating substrate72. The aerosol generating substrate72and the mouthpiece segment78are arranged in coaxial alignment inside a wrapper80(e.g., a paper wrapper) to hold the components in position to form the rod-shaped aerosol generating article70.

The mouthpiece segment78can comprise one or more of the following components (not shown in detail) arranged sequentially and in co-axial alignment in a downstream direction, in other words from the distal end76towards the proximal (mouth) end74of the aerosol generating article70: a cooling segment, a centre hole segment and a filter segment. The cooling segment typically comprises a hollow paper tube having a thickness which is greater than the thickness of the wrapper80. The centre hole segment may comprise a cured mixture containing cellulose acetate fibres and a plasticizer, and functions to increase the strength of the mouthpiece segment78. The filter segment typically comprises cellulose acetate fibres and acts as a mouthpiece filter. As heated vapour flows from the aerosol generating substrate72towards the proximal (mouth) end74of the aerosol generating article70, the vapour cools and condenses as it passes through the cooling segment and the centre hole segment to form an aerosol with suitable characteristics for inhalation by a user through the filter segment.

The heating chamber18comprises a first casing member30, a second casing member32and one or more inductively heatable susceptors42which cooperatively engage to form the heating chamber18and define the interior volume of the heating chamber18. The configuration of the heating chamber18will be discussed in further detail later with reference toFIGS.3to12.

The aerosol generating device10comprises an electromagnetic field generator46for generating an electromagnetic field. The electromagnetic field generator46comprises a substantially helical induction coil48. The induction coil48has a circular cross-section and extends helically around the tubular heating chamber18. The induction coil48can be energised by the power source22and controller24. The controller24includes, amongst other electronic components, an inverter which is arranged to convert a direct current from the power source22into an alternating high-frequency current for the induction coil48.

An outer wall of heating chamber18may include a coil support structure50formed in the outer surface. In the illustrated example, the coil support structure50comprises a coil support groove52which extends helically around the outer surface of the heating chamber18. The induction coil48is positioned in the coil support groove52and is, thus, securely and optimally positioned with respect to the inductively heatable susceptors42.

In order to use the aerosol generating device10, a user displaces the sliding cover28(if present) from the closed position shown inFIG.1to the open position shown inFIG.2. The user then inserts an aerosol generating article70through the open end26into the heating chamber18, so that the aerosol generating substrate72is received in the cavity20and so that the proximal end74of the aerosol generating article70is positioned at the open end26of the heating chamber18, with at least part of the mouthpiece segment78projecting from the open end26to permit engagement by a user's lips.

Upon activation of the aerosol generating device10by a user, the induction coil48is energised by the power source22and controller24which supply an alternating electrical current through to the induction coil48, and an alternating and time-varying electromagnetic field is thereby produced by the induction coil48. This couples with the inductively heatable susceptors42and generates eddy currents and/or magnetic hysteresis losses in the susceptors42causing them to heat up. The heat is then transferred from the inductively heatable susceptors42to the aerosol generating substrate72, for example by conduction, radiation and convection. This results in heating of the aerosol generating substrate72without combustion or burning, and a vapour is thereby generated. The generated vapour cools and condenses to form an aerosol which can be inhaled by a user of the aerosol generating device10through the mouthpiece segment78, and more particularly through the filter segment.

The vaporisation of the aerosol generating substrate72is facilitated by the addition of air from the surrounding environment, for example through the open end26of the heating chamber18, the airflow air being heated as it flows between the wrapper80of the aerosol generating article70and an inner surface36of the heating chamber18. More particularly, when a user sucks on the filter segment, air is drawn into the heating chamber18through the open end26as illustrated by the arrows A inFIG.2. The air entering the heating chamber18flows from the open end26towards the closed end34of the heating chamber18, between the aerosol generating substrate72and the inner surface36of the heating chamber18.

When the air reaches the closed end34of the heating chamber18, it turns through approximately 180° and enters the distal end76of the aerosol generating article70. The air is then drawn through the aerosol generating article70as illustrated by the arrow B inFIG.2, from the distal end76towards the proximal (mouth) end74along with the generated vapour.

A user can continue to inhale aerosol all the time that the aerosol generating substrate72is able to continue to produce a vapour, e.g. all the time that the aerosol generating substrate72has vaporisable components left to vaporise into a suitable vapour. The controller24may adjust the magnitude of the alternating electrical current passed through the induction coil48to ensure that the temperature of the inductively heatable susceptors42, and in turn the temperature of the aerosol generating substrate72, does not exceed a threshold level. Specifically, at a particular temperature, which depends on the constitution of the aerosol generating substrate72, the aerosol generating substrate72will begin to burn. This is not a desirable effect and temperatures above and at this temperature are avoided.

Next, a number of preferred embodiments of the heating chamber18will be described with reference toFIGS.3A to12B.

FIGS.3A to3Bshow various views of a heating chamber318according to an embodiment of the invention.FIG.3Ais a perspective view of the heating chamber318,FIG.3Bis view looking down an open end326of the heating chamber318, andFIG.3Cis an exploded view of the heating chamber318.

The heating chamber318comprises a first casing member330, a second casing member332, and a plurality of inductively heatable susceptors342. The first casing member330, the second casing member332, and the plurality of inductively heatable susceptors342cooperatively engage to form the heating chamber318. In particular, the plurality of inductively heatable susceptors342are arranged to fasten the first casing member330to the second member332.

The first casing member330is tubular, e.g. substantially cylindrical, and has a first longitudinal end360having a slotted configuration comprising a plurality of slots364. The first casing member330has an open end326opposite to the first longitudinal end360, through which the aerosol generating article70may be received. The second casing member332is also tubular, e.g. substantially cylindrical, and has a second longitudinal end362having a slotted configuration comprising a plurality of slots364. The second casing member332has a closed end334opposite to the second longitudinal end362. The first casing member330and the second casing member332are coaxially aligned in a longitudinal direction.

The slotted configuration of the first longitudinal end360of the first casing member330and the slotted configuration of the second longitudinal end362of the second casing member332are arranged so that the first longitudinal end360of the first casing member330and the second longitudinal end362of the second casing member332substantially engage such that they are rotationally locked with respect to one another. In other words, the first longitudinal end360of the first casing member330and the second longitudinal end362of the second casing member332are configured to interdigitate, by virtue of their slotted configurations, to form an integrated tubular body.

Each inductively heatable susceptor342is formed as a rod which extends in a direction parallel to a longitudinal direction of the heating chamber318, i.e. a longitudinal direction of the first casing member330and the second casing member332. The inductively heatable susceptors342are spaced around the circumference of the heating chamber318and integrated within the wall of the heating chamber318, i.e. integrated within the walls of the first casing member330and the second casing member332. In particular, the inductively heatable susceptors342are respectively located along the longitudinal interfaces formed between the slotted configurations of the first longitudinal end360of the first casing member330and the second longitudinal end362of the second casing member332. In this way, the inductively heatable susceptors342act as fastening elements which couple the first casing member330to the second casing member332, whilst also being optimally located to heat the aerosol generating substrate72received within the heating chamber318.

Each inductively heatable susceptor342comprises an inwardly extending portion344that protrudes into the heating chamber318in a radial direction of the heating chamber318. In particular, each inwardly extending portion344forms an elongate ridge on the respective inductively heatable susceptor342, the elongate ridge protruding into the interior volume of the heating chamber318. In this example, each inwardly extending portion344is present along the entire length of the respective inductively heatable susceptor342. However, the skilled person will appreciate that, in other embodiments, the inwardly extending portion344may only be present along a portion of the length of each of inductively heatable susceptor342. The inwardly extending portions344provide a reduced cross-sectional area of the heating chamber318. That is, the inwardly extending portions344extend away from the inner wall of the first casing member330and second casing member332, in an inward direction of the heating chamber318. Advantageously, the inwardly extending portions344may form a friction fit with the aerosol generating substrate72received within the heating chamber318, thereby providing a compressive force on the aerosol generating substrate72. By compressing the aerosol generating substrate72, heat can be transferred more efficiently to the aerosol generating substrate72and more rapid heating can be achieved, whilst at the same time maximising energy efficiency.

Each inductively heatable susceptor342also comprises an outwardly extending portion345. The outwardly extending portion345runs along the length of the respective rod of inductively heatable susceptor342, thereby forming an elongate ridge that protrudes away from the first casing member330and the second casing member332in an outward radial direction. The outwardly extending portion345and the inwardly extending portion344define notches343extending along either side of the length of the inductively heatable susceptor342. The longitudinal interfaces of the slotted configurations of the first casing member330and the second member332are located within the respective notches343on either side of the inductively heatable susceptor342. In this way, the constraint provided by the combination of the outwardly extending portion345and the inwardly extending portion344ensures that first casing member330and the second casing member332are retained within respective notches343of the inductively heatable susceptor342, thereby fastening the first casing member330to the second casing member332.

The first casing member330and the second casing member332may comprise a substantially non-electrically conductive and non-magnetically permeable material. For example, the first casing member330and the second casing member332may comprise a heat-resistant plastics material, such as polyether ether ketone (PEEK). The first casing member330and the second casing member332themselves are not heated by the induction coil48(not shown) during operation of the aerosol generating device10, ensuring that energy input into the inductively heatable susceptors342is maximised. This in turn helps to ensure that the energy efficiency of the device10is maximised. The device also remains cool to the touch, ensuring that user comfort is maximised.

The inductively heatable susceptors342comprise a metal suitable for being inductively heated. The metal is typically selected from the group consisting of stainless steel and carbon steel. The inductively heatable susceptors342could, however, comprise any suitable material including one or more, but not limited, of aluminium, iron, nickel, stainless steel, carbon steel, and alloys thereof, e.g. nickel chromium or nickel copper. With the application of an electromagnetic field in its vicinity, each inductively heatable susceptor342generates heat due to eddy currents and magnetic hysteresis losses resulting in a conversion of energy from electromagnetic to heat. In this way, the aerosol generating substrate72received within the heating chamber318may be heated by the inductively heatable susceptors342to produce an aerosol.

The skilled person will appreciate that these material properties apply equally to the other embodiments of the heating chamber described herein.

In the depicted embodiment, the first casing member330and the second casing member332each comprise two slots364that are evenly spaced apart around the circumference of the first casing member330and the second casing member332respectively. The heating chamber318consequently comprises four inductively heatable susceptors342evenly spaced around the circumference of the heating chamber318, corresponding to the longitudinal interfaces between the first longitudinal end360of the first casing member330and the second longitudinal end362of the second casing member332. However, the skilled person will appreciate that the number of slots364, and thus the number of inductively heatable susceptors342, may vary.

It will also be appreciated by the skilled person that the outer surface of the first casing member330and the second casing member332may be configured to support or receive the induction coil48, as described with reference toFIGS.1and2.

FIGS.4A to4Bshow various views of a heating chamber418according to another embodiment of the invention.FIG.4Ais a perspective view of the heating chamber418,FIG.4Bis view looking down an open end426of the heating chamber418, andFIG.4Cis an exploded view of the heating chamber418.

Again, the heating chamber418comprises a first casing member430, a second casing member432, and a plurality of inductively heatable susceptors442. The first casing member430, the second casing member432, and the plurality of inductively heatable susceptors442cooperatively engage to form the heating chamber418by virtue of the plurality of inductively heatable susceptors442which are arranged to fasten the first casing member430to the second member432.

The first casing member430is tubular, e.g. substantially cylindrical, and has a first longitudinal end460having a slotted configuration comprising a plurality of slots464. The first casing member430has an open end426opposite to the first longitudinal end460. The second casing member432is also tubular, e.g. substantially cylindrical, and has a second longitudinal end462having a slotted configuration comprising a plurality of slots464. The second casing member432has a closed end434opposite to the second longitudinal end362.

However, in this embodiment, the slotted configurations of the first casing member430and the second casing member432are not configured to directly interlock. Instead, the first casing member430and the second casing member432are coaxially aligned with the first longitudinal end460of the first casing member430adjacent to the second longitudinal end462of the second casing member432such that the slots464of the first longitudinal end460of the first casing member430align with respective slots464of the second longitudinal end462of the second casing member432. The inductively heatable susceptors442are elongate rods which are located within each pair of aligned slots464. That is, the inductively heatable susceptors442extend between corresponding slot464of the first casing member430and the second casing member432, thereby fastening the first casing member430to the second casing member432.

In particular, the inductively heatable susceptors442are securely seated within respective slots443by virtue of the respective notches443defined between the inwardly extending portion444and the outwardly extending portion445of each inductively heatable susceptor442. That is, the constraint imposed by the inwardly extending portions444prevents the inductively heatable susceptors442being moved in a radially outward direction, whereas the constraint imposed by the outwardly extending portion445prevents the inductively heatable susceptors442being moved in a radially inward direction.

In the depicted embodiment, the first casing member430and the second casing member432each comprise four slots464that are evenly spaced apart around the circumference of the first casing member430and the second casing member432respectively. The heating chamber318consequently comprises four inductively heatable susceptors442evenly spaced around the circumference of the heating chamber318, situated within each pair of aligned slots464. However, the skilled person will appreciate that the number of slots464, and the corresponding number of inductively heatable susceptors442, may vary.

The skilled person will appreciate that other aspects of the configuration of the inductively heatable susceptors342, the first casing member330and the second casing member332ofFIGS.3A to3Capply equally to the inductively heatable susceptors442, the first casing member430and the second casing member432ofFIGS.4A to4C. For example, the inductively heatable susceptors442comprise inwardly extending portions444which correspond to the inwardly extending portions344.

FIGS.5A to5Cshow various views of a heating chamber518according to another embodiment of the invention.FIG.5Ais a perspective view of the heating chamber518,FIG.5Bis a view looking down an open end526of the heating chamber518, andFIG.5Cis an exploded view of the heating chamber518.

The heating chamber518comprises a first casing member530, a second casing member532, and a plurality of inductively heatable susceptors542. The first casing member530, the second casing member532, and the plurality of inductively heatable susceptors542cooperatively engage to form the heating chamber518. In particular, the plurality of inductively heatable susceptors542are arranged to clamp the first casing member530to the second member532.

The first casing member530and the second casing member532are arranged to engage along their longitudinal edges to form a tubular body, e.g. a cylinder. Specifically, in the depicted embodiment, the first casing member530and the second casing member532are formed as tubular half-sections, which join together along their length to form the heating chamber518. However, the skilled person will appreciate that the number and shape of casing members may be varied.

Each inductively heatable susceptor542is formed as a curved plate which extends around a portion of the exterior of the first casing member530and the second casing member532to couple the first casing member530to the second casing member532. In particular, each plate of inductively heatable susceptor542comprises two inwardly extending portions544which respectively slot into (and through) the first casing member530and the second casing member532, thereby clamping the first casing member530to the second casing member532. The inwardly extending portions544run parallel to the longitudinal direction of the heating chamber518and are located on an inward (i.e. concave) side of the plate of inductively heatable susceptor542, on opposing edges of the plate.

The first casing member530and the second casing member532comprise elongate slots564configured to receive the inwardly extending portions544. Specifically, the elongate slots564are located adjacent and parallel to respective longitudinal edges of the first casing member530and the second casing member532, thereby providing corresponding slots564located either side of the longitudinal joining interface between the first casing member530and the second casing member532. In this way, each inductively heatable susceptor542extends between each pair of corresponding slots564, i.e. between the first casing member530and the second casing member532, to securely fasten the first casing member530to the second casing member532and form the heating chamber518. The inwardly extending portions544may be described as forming a snap-fit within the respective elongate slots564.

Advantageously, as each inductively heatable susceptor542is formed as a plate which extends around the exterior of the heating chamber518, the mass of each inductively heatable susceptor542that may be inductively heated is increased. In particular, the inductively heatable susceptors542have a greater mass closer to the surrounding induction coil48, such that the inductively heatable susceptors542are able to harvest more induction heat. The portions of the plates of inductively heatable susceptor542that extend around the exterior of the heating chamber518may be referred to as outwardly extending portions545.

FIGS.6A and6Bshow different views of a heating chamber618according to another embodiment of the invention.FIG.6Ais a perspective view of the heating chamber618andFIG.6Bis an exploded view of the heating chamber618.

The configuration of the heating chamber618substantially corresponds to the heating chamber418described with reference toFIG.4A to4C. However, the heating chamber618further comprises a ring of inductively heatable susceptor640that is disposed between the first longitudinal end660of the first casing member630and the second longitudinal end662of the second casing member662. Specifically, the ring of inductively heatable susceptor640is coaxially aligned between (and with) the first casing member630and the second casing member632.

In the depicted embodiment, the plurality of rods of inductively heatable susceptors642and the ring of inductively heatable susceptor640are formed as a single (e.g. integrated) component which is configured to fasten the first casing member630to the second casing member632and provide concentrated heating to the aerosol generating substrate72received within the heating chamber618. However, the skilled person will appreciate that the plurality of rods of inductively heatable susceptors642and the ring of inductively heatable susceptor640may be formed as separate components.

In the case of the plurality of rods of inductively heatable susceptors642and the ring of inductively heatable susceptor640being formed as a consolidated unit, the skilled person will appreciate that the respective slots646in the first casing member630and the second casing member632are no longer required to be aligned, and instead may be misaligned.

FIGS.7A to7Cshow various views of a heating chamber718according to another embodiment of the invention.FIG.7Ais a perspective view of the heating chamber718,FIG.7Bis view looking down an open end726of the heating chamber718, andFIG.7Cis an exploded view of the heating chamber718.

The heating chamber718comprises a first casing member730, a second casing member732and a plurality of inductively heatable susceptors742. The configuration of the first casing member730and the second casing732substantially corresponds to the configuration of the first casing member330and the second casing332described with reference toFIGS.3A to3B. However, in this embodiment, the slotted configurations of the first casing member330and the second casing332are not arranged to directly engage and interlock. Instead, the slots764in the first longitudinal end760of the first casing member730are aligned with respective slots764in the second longitudinal end762of the second casing member732. The inductively heatable susceptors742are formed as curved plates which are respectively located within each pair of aligned slots764. In other words, each inductively heatable susceptor742is located within the gap formed between aligned slots of the first longitudinal end760of the first casing member730and the second longitudinal end762of the second casing member732. In this way, the inductively heatable susceptors742extend between (the slots764of) the first longitudinal end760of the first casing member730and the second longitudinal end762of the second casing member732to fasten the first casing member730to the second casing member732. The inductively heatable susceptors742are integrated within the wall of the heating chamber718, i.e. the inductively heatable susceptors742form a portion of the wall of the heating chamber718. Advantageously, this arrangement provides a large surface area for heating an aerosol generating substrate received within the heating chamber718, whilst providing a compact and secure heating chamber718.

The plates of inductively heatable susceptors742comprise one or more inwardly extending portions744. In particular, each inductively heatable susceptor742comprises two inwardly extending portions744that run parallel to the longitudinal direction of the heating chamber718and are disposed on the inner (i.e. concave) surface of the plate of inductively heatable susceptor742, on opposing edges of the plate. As previously described, the inwardly extending portions744provide a reduced cross-sectional area of the heating chamber718, thereby providing a compressive force on the aerosol generating substrate72received within the heating chamber718.

The plates of inductively heatable susceptors742form a snap-fit within respective aligned slots764, thereby securely fastening the first casing member730to the second casing member732. In particular, each inwardly extending portions744comprises a hooked-portion (also referred to as a cantilever) which forms a snap-fit along the respective longitudinal interface of the slotted configurations of the first casing member730and the second casing member732.

In the depicted embodiment, the first casing member730and the second casing member732each comprise two slots764that are evenly spaced apart around the circumference of the first casing member730and the second casing member732respectively. The heating chamber718consequently comprises two inductively heatable susceptors742evenly spaced around the circumference of the heating chamber718, situated within each pair of aligned slots764. However, the skilled person will appreciate that the number of slots764, and the corresponding number of inductively heatable susceptors742, may vary.

FIGS.8A to8Cshow various views of a heating chamber818according to another embodiment of the invention.FIG.8Ais a perspective view of the heating chamber818,FIG.8Bis view looking down an open end826of the heating chamber818, andFIG.8Cis an exploded view of the heating chamber818.

The heating chamber818comprises a first casing member830, a second casing member832and a plurality of inductively heatable susceptors842. The configuration of the first casing member830and the inductively heatable susceptors842substantially corresponds to the configuration of the first casing member730and the inductively heatable susceptors742described with reference toFIGS.7A to7B. However, in this embodiment, the second casing member832does not have a slotted configuration, i.e. there are no slots in the second longitudinal end862of the second casing member832. Instead, the second casing member832is formed as a complete cylindrical tube.

The curved plates of inductively heatable susceptor842are located entirely within respective slots864of the first longitudinal end860of the first casing member830. That is, the inductively heatable susceptors842are integrated within the wall of the first casing member830at locations corresponding to the slots864. The inductively heatable susceptors842do not extend into the second casing member832.

Each plate of inductively heatable susceptor842forms a snap-fit within the respective slot864. In particular, each inwardly extending portion844comprises a hooked-portion (also referred to as a cantilever) which forms a snap-fit along the respective longitudinal interface of the slotted configuration of the first casing member830.

The second longitudinal end862of the second casing member832is coaxially aligned with the first longitudinal end860of the first casing member830such that the second longitudinal end862of the second casing member832forms an interface with the first longitudinal end860of the first casing member830and a longitudinal end of each inductively heatable susceptor842. The second longitudinal end862of the second casing member832may be joined to the first longitudinal end860of the first casing member830and the inductively heatable susceptors842using any suitable fastening mechanism, such as a screw, bolt or adhesive.

FIGS.9A to9Cshow various views of a heating chamber918according to another embodiment of the invention.FIG.9Ais a perspective view of the heating chamber918,FIG.9Bis view looking down an open end926of the heating chamber918, andFIG.9Cis an exploded view of the heating chamber918.

The heating chamber918comprises a first casing member930, a second casing member932and a plurality of inductively heatable susceptors942. The configuration of the first casing member930and the second casing932substantially corresponds to the configuration of the first casing member330and the second casing332described with reference toFIGS.3A to3B. That is, the first longitudinal end960of the first casing member930and the second longitudinal end962of the second casing member932have complementary slotted configurations such that the first longitudinal end960of the first casing member930substantially engages with the second longitudinal end962of the second casing member932so that they are rotationally locked with respect to one another.

However, in this embodiment, the inductively heatable susceptors942are formed as curved or “C” shaped plates which are arranged such that the plates extend around a portion of the exterior of the first casing member930and the second casing member932respectively. In particular, each inductively heatable susceptor942comprises inwardly extending portions944which are respectively located within (and extend through) the longitudinal interfaces formed between the slotted configurations of the first longitudinal end960of the first casing member930and the second longitudinal end962of the second casing member932. In this way, the inductively heatable susceptors942act as fastening elements which couple the first casing member930to the second casing member932.

Specifically, each plate of inductively heatable susceptor942comprises two inwardly extending portions944which run in a direction parallel to the longitudinal axis of the heating chamber918and are located on an inward (i.e. concave) side of the plate of inductively heatable susceptor542, on opposing edges of the plate. In a cross-sectional view, the inwardly extending portions944are seen to correspond to the tips of the “C” shaped plate of inductively heatable susceptor942. Each inductively heatable susceptors942may be described as having two arms, each arm comprising a respective inwardly extending portions944.

The portion of the plates of inductively heatable susceptor942that extend around the exterior of the heating chamber921may be described as outwardly extending portions945. That is, the outwardly extending portions945are outwardly displaced from the wall of the first casing member930and the second casing member932. Advantageously, this provides a greater mass of the inductively heatable susceptors945situated in close proximity to the surrounding induction coil48, thereby increasing the capability of the inductively heatable susceptors945to be inductively heated.

Each inwardly extending portion944and outwardly extending portion945are configured to define notches943extending along either side of each arm of the inductively heatable susceptor942. The longitudinal interfaces of the slotted configurations of the first casing member930and the second member932are located within the respective notches943on either side of each arm of the inductively heatable susceptor942. In this way, the constraint provided by the combination of the outwardly extending portion945and the inwardly extending portion944ensures that first casing member930and the second casing member932are retained within respective notches943of the inductively heatable susceptor942, thereby fastening the first casing member930to the second casing member932.

In the depicted embodiment, the plates of inductively heatable susceptor942, and in particular the outwardly extending portions945, are displaced away from the walls of the first casing member930and the second casing member932around the exterior of the heating chamber918, i.e. there is an air gap between the outwardly extending portions945and the outer surface of the first casing member930and the second casing member932. However, the skilled person will appreciate that, in alternative embodiments, the plates of inductively heatable susceptor942may directly interface, i.e. lie flush, with the respective outer surfaces of the first casing member930and the second casing member932.

FIGS.10A to10Dshow various views of a heating chamber1018according to another embodiment of the invention.FIG.10Ais a perspective view of the heating chamber1018,FIG.10Bis a view looking down a second longitudinal end1062of a second casing member1032,FIG.100is view looking down an open end1026of the heating chamber1018, andFIG.10Dis an exploded view of the heating chamber1018.

The heating chamber1018comprises a first casing member1030, a second casing member1032and a plurality of inductively heatable susceptors1042. The configuration of the first casing member1030and the inductively heatable susceptors1042substantially corresponds to the configuration of the first casing member430and the inductively heatable susceptors442described with reference toFIGS.4A to4B. However, in this embodiment, the first casing member1032does not have a slotted configuration, i.e. there are no slots in the first longitudinal end1060of the first casing member1030. Instead, the first casing member1032is formed as a complete cylindrical tube.

The elongate rods of inductively heatable susceptor1042are located entirely within respective slots1064of the second longitudinal end1062of the second casing member1032. That is, the inductively heatable susceptors1042are integrated within the wall of the second casing member1032at locations corresponding to the slots1064. The inductively heatable susceptors1042do not extend into the first casing member1030.

The first longitudinal end1060of the first casing member1030is coaxially aligned with the second longitudinal end1062of the second casing member1032such that the first longitudinal end1060of the first casing member1030forms an interface with the second longitudinal end1062of the second casing member1032and a longitudinal end of each rod of inductively heatable susceptor1042. The first longitudinal end1060of the first casing member1030may be joined to the second longitudinal end1062of the second casing member1032and the inductively heatable susceptors1042using any suitable fastening mechanism, such as a screw, bolt or adhesive.

In addition, in this embodiment, each inductively heatable susceptor1042comprises an outwardly extending portion1045. The outwardly extending portions1045run along the length of respective rods of inductively heatable susceptor1042, thereby forming an elongate ridge that protrudes away from the first casing member1030and the second casing member1032in a radial direction. In this way, a greater mass of the inductively heatable susceptors1045is provide in close proximity to the surrounding induction coil48, thereby increasing the capability of the inductively heatable susceptors1045to be inductively heated.

Moreover, the skilled person will appreciate that the inductively heatable susceptors1042are securely seated within respective slots1043by virtue of the respective notches1043defined between the inwardly extending portion1044and the outwardly extending portion1045of each inductively heatable susceptor1042. That is, the constraint imposed by the inwardly extending portions1044prevents the inductively heatable susceptors1042being moved in a radially outward direction, whereas the constraint imposed by the outwardly extending portion1045prevents the inductively heatable susceptors1042being moved in a radially inward direction.

FIG.11is a perspective view of a heating chamber1118according to another embodiment of the invention. The heating chamber1118comprises a first casing member1130, a second casing member1132, and a plurality of inductively heatable susceptors1142.

The first casing member1130is tubular and comprises a plurality of slots1164circumferentially spaced around a first longitudinal end1160of the first casing member1130. Similarly, the second casing member1130is tubular and comprises a plurality of slots1164circumferentially spaced around a second longitudinal end1162of the second casing member1132. The plurality of inductively heatable susceptors1142are formed as elongate rods which extend in a direction parallel to the longitudinal direction of the heating chamber1188. Specifically, the inductively heatable susceptors1142are substantially cylindrical rods, but the skilled person will appreciate that their shape may vary.

The first casing member1130and the second casing member1132are coaxially aligned but spatially separated. In particular, the slots1164in the first longitudinal end1160of the first casing member1130are aligned with the slots1164in the second longitudinal end1162of the second casing member1132, and the plurality of inductively heatable susceptors1142extend between the aligned slots1164. Opposing ends of the inductively heatable susceptors1142are situated within opposing slots1164. In this way, a plurality of air gaps are provided between the rods of inductively heatable susceptors1142, thereby allowing increased airflow into the interior of the heating chamber1188.

In this embodiment, the slots1164may be referred to as sockets, as the slots1164are formed as cylindrical cavities which provide constraint around the entire circumference of the end of each rod of inductively heatable susceptor1142. The inductively heatable susceptors1142may be removably inserted into respective slots1164. That is, the inductively heatable susceptor1142are detachable from the first casing member1130and the second casing member1132by sliding the rods of inductively heatable susceptor1142in/out of the slots1164, in a longitudinal direction. In this way, the inductively heatable susceptors1142may be removed and/or replaced during the lifetime of the heating chamber1118.

FIGS.12A and12Bshow different views of a heating chamber1218according to another embodiment of the invention.FIG.12Ais a perspective view of the heating chamber1218andFIG.12Bis a perspective view of the heating chamber1218showing only the second casing member1232and one inductively heatable susceptor1242for the purposes of illustration.

The heating chamber1218comprises a first casing member1230, a second casing member1232, and a plurality of inductively heatable susceptors1242. Such components have a configuration that substantially corresponds to the configuration of the heating chamber1118described with reference toFIG.11. However, in this embodiment, the slots1264are formed as indentations on the circumferential inner surface of the first longitudinal end1260of the first casing member1230and the second longitudinal end1262of the second casing member1232. The indentations are configured to receive a complementary shaped inductively heatable susceptor1242, which may be pressed into the indentation in an outwardly radial direction to form a friction fit. Equally, the inductively heatable susceptor1242may be extracted from the indentation by a force applied in an inwardly radial direction. This may be referred to as a “click-in/click-out” mechanism. The inductively heatable susceptors1242may also be slid into or out of the slots1264in a longitudinal direction of the first casing member1230and the second casing member1232, similar to the embodiment described with reference toFIG.11.

In this way, the inductively heatable susceptors1242are detachable from the first casing member1230and the second casing member1232. The skilled person will appreciate that the heating chambers of the other embodiments may also be configured such that the inductively heatable susceptors are detachable from the first casing member and/or the second casing member.