EP4069019A1

EP4069019A1 - An aerosol generation device having a heating chamber with a thermal guard

Info

Publication number: EP4069019A1
Application number: EP20824132.3A
Authority: EP
Inventors: Tony Reevell
Original assignee: JT International SA
Current assignee: JT International SA
Priority date: 2019-12-03
Filing date: 2020-12-02
Publication date: 2022-10-12
Also published as: JP2023504998A; WO2021110736A1; CN114760871A

Abstract

A heating chamber (108) for an aerosol generation device (100) is provided. The aerosol generation device (100) has a heater (124) positioned externally of the heating chamber (108), and the heating chamber (108) is arranged to receive an elongate substrate carrier (114) having an aerosol substrate (128) arranged towards a first end (134) of the elongate substrate carrier (114). The heating chamber (108) comprises a tubular side wall (126) defining an interior volume and an open first end (110) through which the substrate carrier (114) is receivable into the interior volume and through which air can flow towards the aerosol substrate (128). A contact surface (168) is provided, which is exposed to the interior volume for contacting the substrate carrier (114) at or proximate to the second end of the interior volume. The heating chamber further comprises a second end (111) distal to the open first end (110). A heating region (164) is provided via which heat from the externally positioned heater (124) is applied to the heating chamber (108). The heating chamber also includes a thermal guard (166) at the second end (111) for inhibiting heat flow from the heating region (164) to the at least one contact surface (168).

Description

AN AEROSOL GENERATION DEVICE HAVING A HEATING CHAMBER WITH A

THERMAL GUARD

Field of the Disclosure

The present disclosure relates to an aerosol generation device having a heating chamber with a thermal guard. The disclosure is particularly applicable to a portable aerosol generation device, which may be self-contained and low temperature. Such devices may heat, rather than burn, tobacco or other suitable materials by conduction, convection, and/or radiation, to generate an aerosol for inhalation.

Background to the Disclosure

The popularity and use of reduced-risk or modified-risk smoking devices (also known as vaporisers) has grown rapidly in the past few years as an aid to assist habitual smokers wishing to quit smoking 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 smoking 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 that typically comprises moist leaf tobacco or other suitable aerosolisable material to a temperature typically in the range 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 toxic and carcinogenic by-products of combustion and burning. Furthermore, the aerosol produced by heating the tobacco or other aerosolisable material does not typically comprise the burnt or bitter taste resulting from combustion and burning that can be unpleasant for the user and so the substrate does not therefore require the sugars and other additives that are typically added to such materials to make the smoke and/or vapour more palatable for the user.

In general terms it is desirable to rapidly heat the aerosol substrate to, and to maintain the aerosol substrate at, a temperature at which an aerosol may be released therefrom. It will be apparent that the aerosol will only be released from the aerosol substrate and delivered to user the when there is air flow passing through the aerosol substrate.

Aerosol generation device of this type are portable devices and so energy consumption is an important design consideration. Ensuring that heat generated is supplied to certain parts of the aerosolisable material, and heat flow to other parts is inhibited, can help improve efficiency and provide correct operation. The present disclosure aims to address issues with existing devices and to provide an improved aerosol generation device and heating chamber therefor. Summary of the Disclosure

According to a first aspect of the disclosure, there is provided a heating chamber for an aerosol generation device, which aerosol generation device has a heater positioned externally of the heating chamber, the heating chamber being for receiving an elongate substrate carrier having an aerosol substrate arranged towards a first end of the elongate substrate carrier and the heating chamber comprising: a tubular side wall defining an interior volume and having a first end, through which first end the elongate substrate carrier is receivable into the interior volume and air can flow towards the aerosol substrate, and a second end distal to the first end; a heating region via which heat from the externally positioned heater is applied to the heating chamber; a contact surface exposed to the interior volume for contacting the substrate carrier at or proximate to the second end of the interior volume; and a thermal guard at the second end for inhibiting heat flow from the heating region to the at least one contact surface.

Heat from the externally positioned heater is transferred through the tubular side wall in the heating region to the interior volume. More specifically, heat is transferred from the externally positioned heater by conduction in the radial direction through the tubular side wall to the interior volume. Heat may be transferred from the tubular side wall directly to the aerosol substrate and/or from the tubular side wall indirectly to the aerosol substrate by heating air that flows towards the aerosol substrate from the first end.

By virtue of inhibiting heat flow to the contact surface (for example by interrupting the conductive flow path between the heater and the contact surface), the present arrangement reduces exposure of the tip of the substrate carrier to excessive temperatures from the heater thereby reducing the unwanted production of aerosol from the tip. The tubular side wall may have a dimension, e.g., a diameter, which is greater than a dimension, e.g., a diameter, of the elongate substrate carrier at the location of the contact surface. Thus, there is no contact between the tubular side wall and the elongate substrate carrier at the location of the contact surface, which means that heat is not transferred by conduction directly from the tubular side wall to the tip of the substrate carrier thereby avoiding direct heating of the tip.

The second end may be closed so that air is drawn exclusively through the first end towards the aerosol substrate, and more specifically between an outer layer of the elongate substrate carrier and the tubular side wall towards the aerosol substrate.

The aerosol generation device may comprise one or more heaters positioned externally of the heating chamber. The heating chamber may comprise one or more of said heating regions via which heat from a corresponding one of said one or more externally positioned heaters is applied to the heating chamber. The thermal guard may be arranged to inhibit heat flow from each heating region to the at least one contact surface.

Optionally the at least one contact surface faces the first end of the tubular side wall.

Optionally the thermal guard comprises a first material and the tubular side wall comprises a second material, the first material having a lower thermal conductivity than the second material. In particular, the thermal guard may be made of ceramic or heat resistant plastic such as PEEK. The tubular side wall may made of metal such as stainless steel or copper.

Optionally the at least one contact surface is a surface of the thermal guard.

Optionally the thermal guard is annular.

Optionally the thermal guard is a separate element attached to the tubular side wall.

Optionally the contact surface extends from the tubular side wall into the interior volume.

Optionally the heating chamber further comprises a base at the second end of the tubular side wall.

Optionally the heating region comprises a part of the base.

Optionally the heating region comprises a part of the tubular side wall.

Optionally the thermal guard comprises a part of the base.

Optionally the thermal guard extends inwardly from the base towards the interior volume to provide a platform for supporting the substrate carrier.

Optionally the thermal guard extends across a full width of the base.

Optionally the thermal guard is a separate element attached to the base.

Optionally the heating chamber further comprises an insert comprising the thermal guard, wherein the insert is arranged for removable insertion into the interior volume of the heating chamber.

Optionally, the insert may comprise a mesh or wire net.

Optionally the insert may comprise a plurality of rod-shaped elements.

According to a second aspect of the disclosure, there is provided an aerosol generation device comprising the heating chamber described above and the heater, wherein the heater is mounted to the tubular side wall and the heating region is defined by a region of the tubular side wall at least partially overlapped by the heater.

Optionally the heater is mounted on a surface of the tubular side wall facing away from the interior volume.

Optionally the aerosol generation device further comprises: an electrical power source; and control circuitry configured to control supply of electrical power from the electrical power source to the heater.

Optionally the aerosol generation device further comprises a spacer for retaining the substrate carrier in a central configuration within the heating chamber.

Optionally the spacer is releasably coupled to the aerosol generation device.

According to a third aspect of the disclosure, there is provided an aerosol generation system comprising the aerosol generation device described above and the substrate carrier.

According to a fourth aspect of the disclosure, there is provided an insert for a heating chamber for an aerosol generation device as aforementioned, the insert comprising a thermal guard for inhibiting heat flow from the heating region of the heating chamber to the at least one contact surface and the insert being dimensioned to be inserted in the interior surface of the heating chamber for inhibiting heat flow from the heating region to the at least one contact surface.

Optionally the insert comprises a mesh or wire net or a plurality of rod-shaped elements arranged for holding the thermal guard at a distal end of the insert.

Brief description of the Drawings

Figure 1 is a schematic perspective view of an aerosol generation device according to a first embodiment the disclosure, shown with a substrate carrier of aerosol substrate being loaded into the aerosol generation device.

Figure 2 is a schematic cross-sectional view from a side of the aerosol generation device of Figure 1 , shown with the substrate carrier of aerosol substrate being loaded into the aerosol generation device.

Figure 3 is a schematic perspective view of the aerosol generation device of Figure 1 , shown with the substrate carrier of aerosol substrate loaded into the aerosol generation device.

Figure 4 is a schematic cross-sectional view from the side of the aerosol generation device of Figure 1, shown with the substrate carrier of aerosol substrate loaded into the aerosol generation device.

Figure 5 is a detailed cross-sectional view of a portion of Figure 4, highlighting the interaction between the substrate carrier and the protrusions in the heating chamber and the corresponding effect on the air flow paths.

Figure 6A is a schematic cross-sectional view from the side of the heating chamber of the aerosol generation device of Figure 1.

Figure 6B is a schematic perspective cutaway view of the heating chamber shown in Figure 6A.

Figure 7 is a schematic cross-sectional view from the side of an aerosol generation device according to a second embodiment similar to the first embodiment, but having an alternative air flow arrangement. Figure 8A is a schematic cross-sectional view from the side of a heating chamber according to a third embodiment in which a thermal guard is positioned on the base.

Figure 8B is a schematic perspective cutaway view of the heating chamber shown in Figure 8A.

Figure 8C is a schematic cross-sectional view of an aerosol generation device having a heating chamber according to a third embodiment and comprising a spacer.

Figure 9 shows a schematic perspective view of a heating chamber according to a fourth embodiment, having a side wall and a base formed of rods.

Figure 10 shows a schematic perspective view of a heating chamber according to a fifth embodiment, having a side wall formed of a mesh material or wire net.

Figure 11 shows a schematic cross-sectional view of a heating chamber according to a sixth embodiment, in which a thermal guard is flush with the rest of the base.

Figure 12 shows a schematic cross-sectional view of a heating chamber according to a seventh embodiment, having a thermal guard which extends across the entire base of the heating chamber.

Figure 13A shows a schematic cross-sectional view of a heating chamber according to an eighth embodiment, in which the base of the heating chamber comprises a shelf portion, and the thermal guard sits on the shelf portion within the interior volume of the heating chamber.

Figure 13B shows a perspective view from below of the heating chamber shown in Figure 13A.

Figure 14 shows a schematic cross-sectional view of a heating chamber according to a ninth embodiment, having a thermal guard situated in a central position above the base of the heating chamber, and a contact surface coupled to the upper face of the thermal guard.

Figure 15 shows a schematic cross-sectional view of a heating chamber according to a tenth embodiment, having a thermal guard coupled to the tubular side wall of the heating chamber, with a contact surface coupled to the surface of the thermal guard facing the open first end of the heating chamber.

Figure 16 shows a schematic cross-sectional view of a heating chamber according to an eleventh embodiment, having a thermal guard forming the base and positioned in a recess between the tubular side wall at the lower end of the heating chamber.

Figure 17 shows a schematic cross-sectional view of a heating chamber according to a twelfth embodiment, with a base comprising a recess that does not extend through the entirety of the base, and within the recess is a thermal guard that is flush with the interior surface of the rest of the base.

Figure 18A shows a schematic cross-sectional view of a heating chamber according to a thirteenth embodiment, comprising a proximal section of tubular side wall, a distal section of tubular side wall and an annular section of thermal guard disposed between the proximal and distal sections of tubular side wall to join them together and inhibit heat exchange between the two sections.

Figure 18B is a schematic perspective cutaway view of the heating chamber shown in Figure 18A.

Figure 19A shows a schematic perspective view of an insert according to a fourteenth embodiment, having a side wall and a base formed of rods.

Figure 19B shows a schematic cross-sectional view of an insert according to a fourteenth embodiment being inserted into a heating chamber.

Figure 19C shows a schematic cross-sectional view of an insert according to a fourteenth embodiment inserted in a heating chamber and a substrate carrier inserted in the insert.

Figure 19D is a schematic cross-sectional view of an aerosol generation device having the insert and heating chamber of Figure 19C.

Figure 19E is a schematic cross-sectional view of an aerosol generation device similar to Figure 19D and comprising a spacer.

Detailed Description of the Embodiments First Embodiment

Referring to Figures 1 to 6B, according to a first embodiment of the disclosure, an aerosol generation device 100 comprises an outer casing 102 housing various components of the aerosol generation device 100. In the first embodiment, the outer casing 102 has an irregular shape, but it will be appreciated that any shape is possible, so long as it is sized to fit the components described in the various embodiments set out herein.

A first end 104 of the aerosol generation device 100, shown towards the bottom of each of Figures 1 to 6, is described for convenience as a bottom, base or lower end of the aerosol generation device 100. A second end 106 of the aerosol generation device 100, shown towards the top of each of Figures 1 to 6, is described as the top or upper end of the aerosol generation device 100. During use, the user typically orients the aerosol generation device 100 with the first end 104 downward and/or in a distal position with respect to the user’s mouth and the second end 106 upward and/or in a proximate position with respect to the user’s mouth.

The aerosol generation device 100 has a heating chamber 108 located towards the second end 106 of the aerosol generation device 100. The heating chamber 108 is open towards the second end 106 of the aerosol generation device 100. In other words, the heating chamber 108 has an open first end 110 towards the second end 106 of the aerosol generation device 100. The heating chamber 108 is held spaced apart from an inner surface of the outer casing 102 to inhibit heat flow to the outer casing 102. In order to increase the thermal isolation of the heating chamber 108 further, the heating chamber 108 may be surrounded by insulation, for example a fibrous or foam material, such as cotton wool, aerogel or gas or in other examples vacuum insulation may be provided.

The heating chamber 108 is arranged to receive a substrate carrier 114, also known as a “consumable”, as illustrated in Figures 1 to 5. Typically, the substrate carrier 114 comprises a pre-packaged aerosol substrate 128, such as tobacco or another suitable aerosolisable material provided together with an aerosol collection region 130. Both the aerosol substrate 128 and the aerosol collection region 130 are wrapped in an outer layer 132, and abut one another part way along the substrate carrier 114 at a boundary. The aerosol substrate 128 is heatable to generate an aerosol for inhalation and is located towards the first end 134 (or “tip”) of the substrate carrier 114. The aerosol substrate 128 extends across the entire width of the substrate carrier 114 within the outer layer 132. In other embodiments the heating chamber 108 is arranged to receive the aerosol substrate 128 in other forms, such as loose shredded material or solid material packaged in other ways.

The heating chamber 108 has a side wall 126 extending between a base 112 (located at a second end 111 of the heating chamber) and the open first end 110. The side wall 126 and the base 112 are connected to one another. In some embodiments the side wall 126 and the base 112 are formed as a single piece. In the first embodiment, the side wall 126 is tubular. More specifically, it is cylindrical. However, in other embodiments the side wall 126 has other suitable shapes, such as a tube with an elliptical or polygonal cross section. In yet further embodiments the side wall 126 is tapered.

In the first embodiment, the base 112 of the heating chamber 108 is closed, e.g. sealed or air-tight. That is, the heating chamber 108 is cup-shaped. This can ensure that air drawn from the open first end 110 is prevented by the base 112 from flowing out of the second end 111 and is guided through the aerosol substrate 128 instead. It can also ensure a user inserts the substrate carrier 114 into the heating chamber 108 an intended distance and no further.

A heater 124 is mounted on an external surface of the heating chamber 108. That is to say, the heater 124 is mounted on a surface of the tubular side wall 126 facing away from an interior volume of the heating chamber 108. This can help to protect the heater 124 from damage as the substrate carrier 114 is inserted into the heating chamber 108. The heater 124 is usually electrically powered. In the first embodiment the heater 124 is a film heater comprising an electrically conductive (e.g. metal) track layered on a flexible, electrically insulating backing material (such as polyimide). In the first embodiment, the aerosol generation device 100 is electrically powered. That is, it is arranged to heat the aerosol substrate 128 using electrical power. For this purpose, the aerosol generation device 100 has an electrical power source 120, e.g. a battery. The electrical power source 120 is coupled to control circuitry 122. The control circuitry 122 is in turn coupled to the heater 124. A user operates the aerosol generation device 100 using control means (not shown), arranged to cause coupling and uncoupling of the electrical power source 120 to the heater 124 via the control circuitry 122.

The footprint of the heater 124 defines a heating region 164. In other words, the heating region 164 is a part of the tubular side wall 126 to which heat from the heater 124 is applied to heat the heating chamber 108 (and thereby to supply heat to the aerosol substrate 128). In other embodiments, the heating region 164 is the part(s) of the side wall 126 that is/are heated by a heat source, for example an induction heater, a radiative heater, or even a heater that operates by combustion of a fuel. The heating region 164 is shown in the drawings (see e.g. Figures 6A and 6B) as a cylindrical portion of the side wall 126, but is in some cases discontinuous in an axial and/or circumferential direction along or around the side wall 126. It should be noted that heat does not stop at the heating region 164 only but generally spreads through the tubular side wall 126 by effect of conduction. The heating region 164 is the one for which heat is transferred to the heating chamber 108 in the radial direction (through the side wall 108). The heat transfer along the tubular side wall 126 in longitudinal direction can be reduced by lowering the thickness of the side wall 126 as much as possible (e.g. 100 pm or lower). However, it cannot be totally eliminated. Discontinuous arrangements may be provided by arranging electrically conductive heating tracks to overlie areas that are part of the heating region 164 and not to overlie areas that are not intended to be part of the heating region 164. In cases where induction heating is used, the heating region 164 may be distinguished from other parts of the side wall 126 by the inclusion of materials which show particularly strong responses to induction heating (e.g. ferromagnetic materials) in the heating region 164 and the use of materials which show less strong responses (or indeed little or no response) in other parts of the side wall 126. Similarly, for radiative or combustion heating embodiments, the radiation or combustion jet (e.g. a flame) can be directed at a particular region (or regions) of the side wall 126, such region(s) defining the heating region 164. In some cases, the heating region 164 may even be or include a part or the whole of the base 112.

Generally speaking, the heating chamber 108 comprises a thermal guard 166 which may be part of the chamber or added to it as a permanent or removable part (e.g. as part of a removable insert). In the first embodiment, the thermal guard 166 is a disc of thermally insulating material provided as a separate element attached to the base 112. Preferably the thermal guard 166 comprises a different material from the material used to form the tubular side wall 126, specifically a material having a lower thermal conductivity than the material of the tubular side wall 126 (e.g. a thermally insulating material). This impedes conductive heat flow through the thermal guard 166. The thermal guard 166 is located between the heating region 164 and a contact surface 168, so that the thermal guard 166 impedes the conductive flow of heat from the heating region 164 to the contact surface 168.

As illustrated in Figure 5, the contact surface 168 faces the open first end 110 of the tubular side wall 126. In the first embodiment, the contact surface 168 is the surface of the thermal guard 166 that faces away from the base 112, e.g. upwards or towards the interior volume of the heating chamber 108. This arrangement means that the contact surface 168 is the surface which the tip 134 of the substrate carrier 114 will contact when the substrate carrier 114 has been inserted into the heating chamber 108, as shown. The positioning of the contact surface 168 in this way ensures that conductive heat flow from the heating region 164 to the tip 134 of the substrate carrier 114 is prevented in a simple manner. It can be clearly seen that the thermal guard 166 inhibits conductive heat flow from the heating region to the contact surface 168. That is, conductive heat flow from the heating region 164 to the tip 134 is inhibited or interrupted by the thermal guard 166, because the tip 134 rests on the contact surface 168, so heating by conduction must occur by transmission through the thermal guard 166 which, as noted above, is a thermally insulating element. The centre of the tip 134 is also protected from an excess of hot air flowing in the airflow path. Overheating of the tip 134 is thus inhibited. At the same time, the contact surface 168 is sized to leave an uncovered (e.g. annular) portion of the tip 134 so that air can flow through a gap between the side wall 126 and the substrate carrier 114, to the aerosol substrate 128 at the tip 134 (arrows B in Figure 5).

The thermal guard 166 may comprise any material that can resist deformation upon the force associated with the contact from the tip 134 of the substrate carrier 114 as the substrate carrier 114 is inserted into the heating chamber 108, and also is able to withstand repeated heating to temperatures of approximately 200°C, by virtue of the heater 124. Suitable materials include ceramics such as a machinable glass ceramic, and other suitable materials such as high temperature plastics. In some cases polymers such as polyether ether ketone (PEEK) having an upper working temperature up to 250°C may be used. Note that while further embodiments set out below allow for different arrangements of the thermal guard 166, the considerations above relating to thermal and mechanical stability and suitable materials apply to all embodiments.

The side wall 126 has a thickness much less than the length of the heating chamber 108, which means that transmission of heat through the side wall 126 sees negligible resistance because the side wall 126 is so thin, yet thermal transmission along the side wall 126 (that is, parallel to a central axis or around a circumference of the side wall 126) has a small channel along which conduction can occur, and so heat produced by a heater 124 (which is located on the external surface of the heating chamber 108 in this example) remains localised close to the heater 124, but quickly results in heating of the inner surface of the heating chamber 108. This can help to reduce conduction of heat from the heater 124 to the base 112. In addition, a thin side wall 126 helps to reduce the thermal mass of the heating chamber 108, which in turn improves the overall efficiency of the aerosol generation device 100, since less energy is used in heating the side wall 126.

The heating chamber 108, and specifically the side wall 126 of the heating chamber 108, comprises a material having a thermal conductivity of 50 W/mK or less to further improve the localisation of heating. In the first embodiment, the heating chamber 108 is metal, preferably stainless steel. Stainless steel has a thermal conductivity of between around 15 W/mK to 40 W/mK, with the exact value depending on the specific alloy. As a further example, the 300 series of stainless steel, which is appropriate for this use, have thermal conductivities of around 16 W/mK. Suitable examples include 304, 316 and 321 stainless steel, which have been approved for medical use, are strong and have a low enough thermal conductivity to allow the localisation of heat described herein. In general metals are suitable materials, since they are strong, malleable and easy to shape and form. In addition their thermal properties vary widely from metal to metal, and can be tuned by careful alloying, if required. In this disclosure, “metal” refers to elemental (i.e. pure) metals as well as alloys of more than one metal or metals with other elements, e.g. carbon. Note that in the illustrated embodiment the base 112 is thicker than the side wall 126, for example 2 to 10 times as thick as the side wall 126. In some cases this may result in a base 112 which is between 200 pm and 500 pm thick, for example approximately 400 pm thick, and which can help to provide support to the side wall 126 to strengthen it against bucking or other damage.

A plurality of protrusions 140 may be provided around the side wall 126, extending into the interior of the volume defined by the side wall 126. The width of the protrusions 140, around the circumference of the side wall 126, is small relative to their length, parallel to the central axis of the side wall 126 (or broadly in a direction from the base 112 to the open first end 110 of the heating chamber 108). Four is a preferred number of protrusions 140 for holding a substrate carrier 114 in a central position within the heating chamber 108, although other numbers could be used. The protrusions 140 extend towards and engage the substrate carrier 114 when the substrate carrier 114 is inserted in the heating chamber 108. The protrusions provide and maintain a controlled gap for the air flow path (arrows B) between the inner surface of the heating chamber 108 (between adjacent protrusions 140) and the substrate carrier 114. The protrusions 140 are formed by deforming or indenting the side wall 126, which has the advantage that they are unitary with the side wall 126 so have a minimal effect on heat flow. In addition, protrusions 140 formed in this way do not add any thermal mass, as would be the case if an extra element were to be added to the inner surface of the side wall 126 of the heating chamber 108. Lastly, indenting the side wall 126 as described increases the strength of the side wall 126 by introducing portions extending transverse to the side wall 126.

The aerosol generation device 100 works by both conducting heat from a surface of protrusions 140 that engage against the outer layer 132 of substrate carrier 114 and by convective heating in which air in the air gap between the inner surface of the side wall 126 and the outer surface of a substrate carrier 114 is heated and drawn through the substrate carrier 114.

It will be apparent that to conduct heat into the aerosol substrate 128, the surface 145 of each protrusion 140 engages with the outer layer 132 of substrate carrier 114. To mitigate the effects of any variation in the diameter of the substrate carrier 114 due to manufacturing tolerances, damage, or shrinking due to heating and drying, the protrusions 140 are preferably dimensioned to extend far enough into the heating chamber 108 to cause compression of the substrate carrier 114. This in turn ensures an interference fit between the surfaces 145 of each protrusion 140 and the outer layer 132 of the substrate carrier 114. This compression of the outer layer 132 of the substrate carrier 114 may also result in better conduction of heat through the aerosol substrate 128 by squeezing air out of the aerosol substrate 128.

Figure 5 shows an enlarged view of the heating chamber 108 and substrate carrier 114. As can be seen, arrows B illustrate the air flow paths that provide the convective heating described above. Air flows down the side of the substrate carrier 114 (in front of and behind the protrusions 140) in order to enter the tip 134. The air flow paths occupy the equally spaced gap regions between the four protrusions 140.

The space bounded by adjacent protrusions 140, the side wall 126, and the outer layer 132 of the substrate carrier 114 defines the area available for air flow. The smaller this space is, the harder that a user has to suck to draw air through the aerosol generation device 100 (known as increased draw resistance). The size, number and spacing of the protrusions 140 can be adjusted to give a satisfying draw resistance, which is neither too low nor too high, and also to adjust allows the balance between conductive and convective heating. The heating chamber 108 can also be made larger to increase the air flow channel between the side wall 126 and the substrate carrier 114, but there is a practical limit on this before the heater 124 starts to become ineffective as the gap is too large. Typically a gap of 0.2 mm to 0.3 mm around the outer surface of the substrate carrier 114 is a good compromise, which allows fine tuning of the draw resistance within acceptable values by altering the dimensions of the protrusions 140. Because the portions of the side wall 126 which are heated (the heating region 164) can correspond broadly to the locations of the protrusions 140 (or a slightly larger region of the side wall 126), the heat generated is conducted to the substrate carrier 114 by the protrusions 140, while heat is inhibited from conduction along the tubular side wall 126 towards the open first end 110 and the base 112 by the thin side wall 126. The open first end 110 and the base 112 show a lower rise in temperature on heating than the protrusions do, in part because the open first end 110 and the base 112 do not directly receive heat (e.g. they are located away from the heating region 164), and also due to the low longitudinal conductance provided by the thin side wall 126. In other locations, e.g. between adjacent protrusions 140 air is heated, which convectively heats the aerosol substrate 128.

In some cases further localisation of heating may be provided by a heat conductive layer (e.g. a thin layer of metal such as copper - not shown) between the heater 124 and the heating chamber 108. In such cases, the heating region 164 can be defined as the region coated by the heat conductive layer, which may be larger than the heater 124 alone. Such a heat conductive layer can also help to further improve thermal contact between the heater 124 and the heating chamber 108, and to conduct heat to the protrusions 140. It will be appreciated that a heat conductive layer can be used with other heating means (combustion, radiation, induction heating, etc.) in order to define a heating region 164, in which heat received from a heat source is “spread out” over the extent of the heat conductive layer.

When a user wishes to use the aerosol generation device 100, the user first loads the aerosol generation device 100 with the substrate carrier 114 by inserting the substrate carrier 114 into the heating chamber 108. The substrate carrier 114 is inserted into the heating chamber 108 oriented such that the first end or tip 134 of the substrate carrier 114 enters the heating chamber 108 first, so that the aerosol substrate 128 is located adjacent to the base 112 with the tip 134 contacting the contact surface 168. The substrate carrier 114 is inserted into the heating chamber 108 until the tip 134 of the substrate carrier 114 rests against the base 112 of the heating chamber 108. In this embodiment there is an additional effect from the interaction between an upper edge 142 of the protrusions 140 and the boundary of the aerosol substrate 128 and the less compressible adjacent aerosol collection region 130 of the substrate carrier 114, which alerts the user that the substrate carrier 114 has been inserted sufficiently far into the aerosol generation device 100.

It will be seen from Figures 3 and 4 that when the substrate carrier 114 has been inserted into the heating chamber 108 as far as it will go, only a part of the length of the substrate carrier 114 is inside the heating chamber 108. A remainder of the length of the substrate carrier 114 protrudes from the heating chamber 108. At least a part of the remainder of the length of the substrate carrier 114 also protrudes from the second end 106 of the aerosol generation device 100 and can be used as a mouthpiece through which a user draws aerosol from the aerosol substrate 128 by sucking. In other embodiments all, or substantially all, of the substrate carrier 114 may be received in the aerosol generation device 100, such that none or substantially none of the substrate carrier protrudes from the aerosol generation device 100.

The thermal guard 166 provides a support platform above the base 112 of the heating chamber 108 and the length of the aerosol substrate 128 (between the tip 134 and the aerosol collection region 130) corresponds approximately to the distance between the top edge 142 of the protrusions 140 (closest to the open first end 110 of the heating chamber 108) and the contact surface 168. In another embodiment, the distance between the top edge 142 of the protrusion 140 and the uppermost portion of the thermal guard 166 is slightly shorter than the length of the aerosol substrate 128. This means that the tip 134 of the substrate carrier 114 extends slightly past the uppermost part of the thermal guard 166, thereby causing compression of the aerosol substrate 128 at the tip 134 of the substrate carrier 114. Thus the thermal guard 166 could be partially inserted into the substrate carrier 114 due to the compression of the aerosol substrate 128, but without the tip 134 touching the inner surface of the base 112 to ensure the thermal guard 166 inhibits conductive heat flow from the base 112 to the aerosol substrate 128.

There is an annular region around the thermal guard 166 that provides an air flow passage from the gap between the inner surface of the side wall 126 (between adjacent protrusions 140 in the vicinity of the protrusions 140) and the outer layer 132 of the substrate carrier 114 to the tip 134 of the substrate carrier 114. A thermal guard 166 extending at least about 1 mm higher (towards the open first end 110 of the heating chamber 108) than the rest of the base 112 can achieve this effect.

In use, when the user switches the aerosol generation device 100 on, electrical power from the electrical power source 120 is supplied to the heater 124 via (and under the control of) the control circuitry 122. The heater 124 causes heat to be conducted via the heating region 164 to the aerosol substrate 128, heating the aerosol substrate 128 to a temperature at which it can begin to release vapour or aerosol. In addition, convective heating of the aerosol substrate 128 occurs, as set out above.

Once heated to a temperature at which the aerosol can begin to be released, the user may inhale the aerosol by sucking the aerosol through the second end 136 of the substrate carrier 114. That is, the aerosol is generated from the aerosol substrate 128 located at the first end 134 of the substrate carrier 114 in the heating chamber 108 and drawn along the length of the substrate carrier 114, through the aerosol collection region 130 in the substrate carrier 114, to the second end 136 of the substrate carrier, where it enters the user’s mouth. This flow of aerosol is illustrated by arrow A in Figure 4. It will be appreciated that, as a user sucks aerosol in the direction of Arrow A in Figure 4, aerosol flows from the vicinity of the aerosol substrate 128 in the heating chamber 108. This action draws ambient air into the heating chamber 108 (via flow paths indicated by Arrows B in Figures 4 and 5) through the open first end 110 from the environment surrounding the aerosol generation device 100. This ambient air flows in the space provided between the side wall 126 of the heating chamber 108 and the outer layer 132 of the substrate carrier 114 where it is heated by the heater 124. The heated air in turn heats the aerosol substrate 128 to cause generation of aerosol as the heated air is drawn through the aerosol substrate 128.

The user can continue to inhale aerosol all the time that the aerosol substrate 128 continues to produce the aerosol, e.g. all the time that the aerosol substrate 128 has vaporisable components left to vaporise into a suitable aerosol and is held at an appropriate temperature. The control circuitry 122 adjusts the electrical power supplied to the heater 124 to ensure that the temperature of the aerosol substrate 128 does not exceed a threshold level, for example temperatures at which the aerosol substrate 128 will begin to burn.

While the heating chamber 108 described above is set out in the context of a heating chamber 108 contained within the aerosol generation device 100, the example shown in Figures 6A and 6B is an indication that the disclosure extends to the heating chamber 108 alone. Indeed, while shown in Figures 6A and 6B as having a heater 124 on the outer surface of the heating chamber 108, the disclosure extends to a heating chamber 108 without such a heater 124, having only a heating region 164 for receiving heat from a heat source.

Alternative embodiments will now be described by illustrating the heating chamber 108 alone. By analogy to Figures 6A and 6B of the first embodiment, the heating chamber 108 of any of the following embodiments may replace the heating chamber 108 shown in the aerosol generation device 100 in Figures 1 to 4, whereby the operation of the aerosol generation device is broadly the same as set out above.

Second Embodiment

Referring to Figure 7, an aerosol generation device 100 according to a second embodiment is identical to the aerosol generation device 100 of the first embodiment described with reference to Figures 1 to 6, except where explained below, and the same reference numerals are used to refer to similar features.

The aerosol generation device 100 of the second embodiment has an arrangement for allowing air to be drawn into the heating chamber 108 during use that is different to that of the first embodiment. In more detail, an airflow passage or channel 113 is provided in the base 112 of the heating chamber 108. In the second embodiment the channel 113 is located in the middle of the base 112. It extends through the base 112, so as to be in fluid communication with the environment outside of the heating chamber 108. In other embodiments, the channel 113 is provided elsewhere on the base 112, multiple channels through the base 112 are provided, one or more channels are provided through the side wall 126 adjacent to the base 112 or the base 112 and/or part of the side wall 126 are perforated.

An inlet 137 is provided that extends through the outer casing 102. The inlet 137 is arranged in to be in fluid communication with the channel 113. In the second embodiment, the inlet 137 is located part way along the length of the outer casing 102, between the first end 104 and the second end 106 of the aerosol generation device 100. The outer casing 102 also defines a void 139 and between the inlet 137 in the outer casing 102 and the channel 113 in the base 112 of the heating chamber 108. The void 139 provides fluid communication between the inlet 137 and the channel 113 so that air can pass from the environment outside of the outer casing 102 into the heating chamber 108 via the inlet 137, the void 139 and the channel 113. In other words the base 112 is traversed by an air flow passage 113.

During use, as aerosol is inhaled by the user at the second end 136 of the substrate carrier 114, air is drawn into the heating chamber 108 from the environment surrounding the aerosol generation device 100. More specifically, air passes through the inlet 137 in the direction of arrow C into the void 139. From the void 139, the air passes through the channel 113 in the direction of arrow D into the heating chamber 108. This allows initially the aerosol, and then the aerosol mixed with the air, to be drawn through the substrate carrier 114 in the direction of arrow D for inhalation by the user at the second end 136 of the substrate carrier 114.

The thermal guard 166 also has an aperture (aligned with the channel 113 in the base 112) through which air enters the interior of the heating chamber 108. That is to say that the thermal guard 166 in this example is also traversed by the air flow passage. In the example shown, the air drawn in via arrows C and D is fresh air from the outside, meaning that it is not heated to a point where it can generate aerosol as it passes through the aerosol substrate 128. Heating occurs via heater 124 and heating region 164, primarily conductively. However, since there are protrusions 140 in this embodiment, there is an air gap between the inner surface of the heating chamber 108 (between the protrusions) and the outer layer 132 of the substrate carrier 114. This means that convective heating can also occur in the manner set out above. In other examples, this air gap need not exist and the aerosol substrate 128 can be heated by conduction while cool fresh air is drawn in through the alternative air flow paths shown as arrows C and D in Figure 7. This arrangement decouples the conductive heating (via protrusions 140) from the draw resistance discussion set out above in respect of the first embodiment. In other words, the contact surface area of the protrusions 140 can be chosen freely, without regard for the effect on draw resistance, as the air flow path is no longer affected by the protrusions 140, coming instead through the base 112 of the heating chamber. The effect by which the tip 134 is prevented from overheating by the thermal guard 166 is still present in the sense that the heater 124 heats the heating region 164 and the protrusions 140 to supply heat to the aerosol substrate 128 through the outer layer 132 of the substrate carrier, but conductive heat transfer to the contact surface 168 (and thence to the tip 134) is interrupted by the presence of the thermally insulating thermal guard 166. In some cases, the air may be heated as it enters the heating chamber 108, such that the air assists in transferring heat to the aerosol substrate 128 by convection.

In variations of the second embodiment, the inlet 137 is located in different locations. In one particular embodiment, the inlet 137 is located at the first end 104 of the aerosol generation device 100. This allows the passage of air through the entire aerosol generation device 100 to be broadly linear, e.g. with air entering the aerosol generation device 100 at the first end 104, which is typically oriented distal to the user during use, flowing through (or over, past, etc.) the aerosol substrate 128 within the aerosol generation device 100 and out into the user’s mouth at the second end 136 of the substrate carrier 114, which is typically oriented proximal to the user during use, e.g. in the user’s mouth.

Third Embodiment

Referring to Figures 8A and 8B, a heating chamber 108 according to a third embodiment is identical to the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features. The arrangement in the third embodiment is very similar to the arrangement shown in Figures 6A and 6B, but in Figures 8A and 8B no protrusions 140 are present. The thermal guard 166 inhibits the heat flow from the heating region to the contact surface 168 in the same way as set out above.

In this embodiment, the heating chamber 108 may still provide conductive heating by contacting the substrate carrier 114 around its circumference and using an air flow path such as that in the second embodiment. In further examples, the heating chamber 108 may be non-circular (e.g. elliptical, square, etc.) in cross-section, and may contact the substrate carrier 114 at parts of its circumference to provide conductive heating and compression.

In yet another example, the gap between the heating chamber and the substrate carrier can be obtained by spacer positioned above, at or proximate to the open first end 110 of the heating chamber 108. In yet further examples the heating may be entirely convective and there may be no contact at all between the side wall 126 and the outer surface 132 of the substrate carrier 114. As illustrated in Figure 8C an exemplary spacer 190 may be provided above the open first end 110 of the heating chamber 108 to allow the substrate carrier 114 to be held centrally within the heating chamber 108 when no protrusions 140 are present. In other words, the substrate carrier 114 is spaced away from the inner surface of the side wall 126, leaving an annular air gap between the outer surface 132 of the substrate carrier and the tubular side wall 126. That is to say, the spacer 190 can retain the substrate carrier 114 in a central configuration within the heating chamber 108.

In the illustrated embodiment, the spacer 190 has an annular cross-section through which the substrate carrier 114 may be inserted and in which the substrate carrier 114 is held snugly. The spacer 190 is provided with perforations to allow air flow into the heating chamber (as shown by arrows B). Alternatively, the spacer 190 may not extend fully around the circumference of the substrate carrier 114, being of an interrupted annular cross section, or formed of discrete protrusions which hold the substrate carrier centrally in the heating chamber 108.

Other configurations of the spacer 190 may allow the air to be drawn through the spacer 190 while maintaining the substrate carrier 114 in the heating chamber 108, for example, the spacer 190 may have a gap or gaps at which it is not in contact with a substrate carrier 114 inserted therethrough, through which gaps air may be drawn in use. In general, spacers 190 may be suitable to for use with air flow paths corresponding to either the first or second embodiments described above. It will be appreciated in embodiments of the spacer 190 forming a tight seal around the substrate carrier 114 when inserted and in use air may be prevented from being drawn in through the open first end 110 of the heating chamber. Such configurations are compatible with heating chambers 108 according to the second embodiment described above in which air flows into the device through an inlet 137 and continues into the heating chamber 108 via a channel 113 in the base 112.

The spacer 190 is shown flush with the outer casing 102, at the second end 106 of the aerosol generation device 100. In some embodiments, the spacer 190 may be recessed into the aerosol generation device 100, for example so that the outer casing protects the spacer 190 from damage.

In this embodiment, the spacer 190 is permanently fixed into the aerosol generation device 100, but in some cases it may be removable (in other words the spacer 190 may be releasably coupled or releasably couplable to the aerosol generation device 100), for example the spacer 190 may clip onto the outer body 102 of the aerosol generation device 100. In such embodiments the spacer 190 may be attached to the substrate carrier 114 prior to both the substrate carrier 114 and the spacer 190 being introduced to the aerosol generation device 100 such that the tip 134 of the substrate carrier 114 rests against the contact surface 168 and the spacer 190 clips into place, as shown in Figure 8C. Attaching the spacer 190 to the substrate carrier 114 prior to insertion into the heating chamber 108 may allow a user to monitor the attachment process carefully, thereby reducing possible damage to the substrate carrier 114. In addition, the user can check that the spacer 190 has correctly fit onto the substrate carrier 114 by visual inspection

While embodiments with spacers 190 are particularly useful for embodiments without protrusions 140, they also may be used in embodiments in which there are protrusions 140 or other portions for contacting the substrate carrier 114 and holding it in place within the heating chamber 108. For example the spacer 190 can provide additional support (additional to the protrusions 140 or other contacting portions) for centring the substrate carrier 114, and may also help retain heat inside the heating chamber 108 by partially blocking the open first end 110 to reduce flow of heated air out of the heating chamber 108.

Fourth Embodiment

Referring to Figure 9, a heating chamber 108 according to a fourth embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features.

The side wall 126 of the heating chamber 108 of Figure 9 comprises a plurality of rod-shaped elements 176. In the example shown, the rods 176 are bent towards a central axis at the second end 111 of the heating chamber 108 to form a base, although this is optional and in some cases the base may be solid, similar to the previous embodiments. In yet further examples, the tubular side wall 126 may be solid, and the base is formed of rods. The base of the heating chamber 108 shown in Figure 9 comprises a thermal guard 166 having an upwardly facing contact surface 168. A heating region 164 is shown part way along the rods 176.

Further, the heating chamber 108 is configured to receive the elongate substrate carrier 114 in a similar manner to previous embodiments. The heating chamber 108 is shown with a rim 107 coupled to the proximal end of the heating chamber 108. This is an optional feature displayed in Figure 9, but allows the upper ends of the rods to be secured in the rim 107, thereby helping to protect the rods from damage, e.g. bending. The heating chamber 108 may be configured so that the heating region 124 of the tubular side wall 126 heats the heating chamber 108, or the elongate substrate carrier 114 directly, for example by providing a heater (such as heater 124 in Figures 1 to 5) around the outside of the heating chamber 108 in the heating region 164. The embodiment shown in Figure 9 allows the heat flow path to the contact surface 168 to be reduced relative to a solid wall of the same thickness as the diameter of the rods 176. The rod-shaped elements 176 can be thought of as a solid side wall 126 (see e.g. Figures 6A and 6B) with some portions removed to form apertures, leaving the rods 176 as shown. Of course the heating chamber 108 need not be formed by removal of wall sections to leave rods 176, but may preferably be formed by assembling a series of appropriately shaped rods 176 and joining them together to form the structure shown in Figure 9. The effect of the resulting structure is to remove some of the conductive heat transfer channel relative to a solid side wall, while allowing a larger air gap to allow convective heat transfer. In other words, while the thermal guard 166 has an increased thermal resistivity relative to the material from which the side wall 126 (or elongate rods 176) is formed, the geometry of the heating chamber 108 shown in Figure 9 is such that there is an increased thermal resistance in a vertical direction (relative to a solid side wall 126), since the heat transfer channel is reduced (assuming that the elongate rods have a thickness the same as the thickness of the tubular side wall 126).

The rods 176 may be arranged to perform much the same role as the protrusions 140 in the first and second embodiments; providing compression of the aerosol substrate 128 and maintaining good thermal contact with the substrate carrier 114, even in cases where the aerosol substrate 128 shrinks as it is heated and dries out.

Fifth Embodiment

Referring to Figure 10, a heating chamber 108 according to a fifth embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features.

The heating chamber 108 is similar to that of Figure 9; however the side wall 126 and the base are constructed of a mesh 180, rather than of rod-shaped elements 176 of Figure 9. In some embodiments the heating chamber 108 may include both the mesh 180, and the rod-shaped elements. In other examples, the base may be formed of a solid material and only the side wall 126 is formed of mesh (or vice-versa). A heating region 164 is shown part way along the side wall 126.

The heating chamber 108 is shown with a rim 107 coupled to the proximal end of the heating chamber 108. This serves to protect the upper end of the mesh 180 from damage.

The heating chamber 108 may be configured so that the heating region 124 of the tubular side wall 126 heats the heating chamber 108 or the elongate substrate carrier 114 directly. The embodiment shown in Figure 10 allows the heat flow path to the first end 134 of the elongate substrate carrier 114 to be reduced. The embodiment of Figure 10 may be configured so that the base of the heating chamber 108 has a thermal guard 166 positioned inside the heating chamber 108 with a contact surface 168 being provided by the upper surface of the thermal guard 166.

Similarly to the discussion of the fourth embodiment above, the mesh 180 can be thought of as reducing the conductive heat transfer channel relative to a solid side wall 126 as it is similar to a solid side wall with parts removed, thereby reducing the conductive heat transfer channel from the heating region 164 to the contact surface. This has the effect of increasing thermal resistance relative to a solid tubular side wall 126. Thus, the mesh side wall 126 inhibits conductive heat flow long the wall to the base. Any heat which is conducted as far as the base 112 is further inhibited from causing overheating of the tip 134 by the thermally insulating thermal guard 166, which blocks conductive heat transfer to the tip 134.

The mesh 180 is also permeable to air, so can help to improve air flow and reduce draw resistance, thereby increasing design freedom in this regard.

In addition to the mesh and rod variants of Figures 9 and 10, the thermal resistance can be increased by selectively thinning all or part of the side wall 126, or selectively forming holes in the side wall 126. Each of these ways of increasing the thermal resistance can be applied to the solid tubular side wall 126 designs described herein.

Sixth Embodiment

Referring to Figure 11 , a heating chamber 108 according to a sixth embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features.

The distal end 111 of the heating chamber includes a base portion 112 formed as a unitary part with the side wall 126, and which extends radially inward from the side wall 126, but does not fully close the distal end 111 , leaving a central aperture.

The aperture is filled by a thermal guard 166, closing the distal end 111. The thermal guard has a contact surface 168 shaped and sized to have an area at least as large as the cross sectional area of the substrate carrier 114, meaning that the tip 134 can fit entirely within the contact surface 168. The thermal guard 166 thus inhibits heat flow from the heating region 164 part way along the tubular side wall 126 to the contact surface 168. In the embodiment of Figure 11 the thermal guard is flush with the base 112 of the heating chamber 108. In other examples the thermal guard 166 may extend toward the open first end 110, and so not be flush with the base 112, but rather may form a platform. In this latter example, the thermal guard 166 may not have a contact surface 168 sized to have an area at least as large as the cross sectional area of the substrate carrier 114, instead resulting in an arrangement similar to that shown in the first embodiment. The aperture in the base portion 112 reduces the thermal mass of the heating chamber 108 (relative to a full base such as in the first embodiment), thereby improving efficiency in supplying heat to the heating chamber 108.

Seventh Embodiment

Referring to Figure 12, a heating chamber 108 according to a seventh embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features.

A base 112 is formed of unitary construction with the tubular side wall 126 at the second end 111 of the side wall 126. There are no perforations in the base 112 in this embodiment. A thermal guard 166 is coupled to the base, such that it positioned above the base 112 within the heating chamber 108, and such that the thermal guard 166 extends across the entire base. The thermal guard 166 has a contact surface 168 such that the first end of the elongate substrate 134 will contact the contact surface 168 when fully inserted into the heating chamber 108. Arranging the thermal guard 166 so that it extends across the entire base 112 ensures that even if the substrate carrier is not inserted correctly (i.e. coaxially with the tubular wall 126), but is off-centre, the tip 134 will nevertheless be in contact with the contact surface 168, thus interrupting a conductive heat flow path from the heating region 164 to the tip 134.

Eighth Embodiment

Referring to Figures 13A and 13B, a heating chamber 108 according to an eighth embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features. Figure 13A shows a cross-sectional view of the heating chamber 108 of this embodiment while Figure 13B shows a perspective view of the heating chamber 108 from below, with a cutaway to show the interior of the heating chamber 108.

The distal end 111 of the heating chamber includes a base portion 112 formed as a unitary part with the side wall, and which extends radially inward from the side wall, but does not fully close the distal end 111, leaving a central aperture. In other words the base portion 112 forms a shelf with a perforation in the middle of the heating chamber 108. In the embodiment shown a thermal guard 166 is supported by the shelf formed by the base portion 112. The thermal guard has a contact surface 168, which is the surface facing the open first end 110. In use, when a first end of an elongate substrate carrier 114 is fully inserted into the heating chamber, the first end 134 contacts the contact surface 168 of the thermal guard 166.

The construction of a heating chamber 108 according to the eighth embodiment may be simpler than for other embodiments, as the thermal guard 166 can be cut to size, pushed to the bottom 111 and held there by a friction or interference fit. In addition, the aperture in the base portion 112 reduces the thermal mass of the heating chamber 108 (relative to the seventh embodiment), thereby improving efficiency in supplying heat to the heating chamber 108.

Ninth Embodiment

Referring to Figure 14, a heating chamber 108 according to a ninth embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features.

A thermal guard 166 is coupled to the base 112 of the heating chamber at the distal second end 111. A contact surface 168 is coupled on to the thermal guard 166, at the distal second end of the heating chamber 111 such that the contact surface 168 is located closer to the open first end 110 than the thermal guard is.

The contact surface 168 is configured such that when an elongate substrate carrier 114 is fully inserted into the heating chamber 108 the first end of the elongate substrate carrier 134 contacts the contact surface 168. The thermal guard 166 is formed of thermally insulating material. The thermal guard inhibits the heat flow between the heating region and the contact surface 168 because heat flow from the heating region 164 must be conducted down the side wall 126 and then through the thermal guard 166 in order to reach the tip 134 of the substrate carrier 114.

While in previous embodiments the upper surface of the thermal guard 166 was the contact surface 168, in this embodiment the thermal guard 166 and the contact surface 168 are decoupled from one another. This means that the contact surface 168 may be formed of a different material from the thermal guard 166. This can mean that each element can be formed of materials which are most appropriate for the task. In addition, the interface between the thermal guard 166 and the contact surface 168 may introduce further insulating effects by virtue of interfacial thermal resistance. Therefore where the contact surface 168 is formed of a layer separate to the thermal guard 166 the thermal guard 166 may be constructed of less expensive, or less thermally resistive materials in some embodiments. Tenth Embodiment

Referring to Figure 15, a heating chamber 108 according to a tenth embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features.

The thermal guard 166 of the tenth embodiment is a separate annular element and is attached to the tubular side wall 126, extending radially inward from the side wall 126. A heating region 164 is located on the tubular side wall 126 part way between the two ends 110, 111.

In this embodiment the thermal guard 166 extends perpendicularly to the tubular side wall 126 and into the interior volume. In related embodiments the thermal guard 166 may be formed of any number of projections, separate or linked together, and which project inwardly from the tubular side wall 126 of the heating chamber 108.

The thermal guard 166 has a separate layer forming the contact surface 168 and facing the open first end 110 of the heating chamber (similar to the contact surface 168 applied in Figure 14). The thermal guard 166 inhibits the heat flow from the heating region 164 (located part way along the side wall 126) to the contact surface 168. In some examples the contact surface 168 may not be in contact with the side wall 126 to further inhibit conductive heat flow to the contact surface 168, and thereby inhibit heat flow to the tip 134. The thermal guard 166 may be formed of a material such as plastic, whilst the contact surface 168 may be formed of a harder wearing material such as a metal. The contact surface 168 may also distribute pressure across the thermal guard 166 evenly.

The aperture in the centre of the thermal guard 166 and contact surface 168 may be particularly useful in embodiments which make use of the alternative air flow path shown in the second embodiment.

Eleventh Embodiment

Referring to Figure 16, a heating chamber 108 according to an eleventh embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features.

The base 112 is formed by a thermal guard 166 coupled to the tubular side wall inside the heating chamber at the distal end and extending across the entire cross section of the heating chamber 108. In an alternative embodiment the thermal guard 166 may couple with the tubular side wall 126 outside of the heating chamber, from below the distal end of the tubular side wall 126. A heating region 164 is located on the tubular side wall 126 part way between the two ends 110, 111. In this example the contact surface 168 is simply the upper surface of the thermal guard 166, facing the open first end 110 of the heating chamber. The absence of any base at all reduces thermal mass, and improves efficiency. In addition, assembly of this embodiment is very simple as the thermal guard 166 need only be cut to shape and inserted into the open first end 110 of the tubular side wall.

Twelfth Embodiment

Referring to Figure 17, a heating chamber 108 according to a twelfth embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features.

In the twelfth embodiment, the base 112 has a recess formed within it, and a thermal guard 166 is provided within the recess. In the embodiment shown the thermal guard 166 is flush with the base 112.

In a further embodiment the thermal guard 166 may extend proximally of the base 112 toward the open first end 110 of the heating chamber 108, forming a platform secured in place via the recess.

In any event the thermal guard operates to provide a contact surface 168 facing the open first end 110 of the heating chamber 108. In this way the conductive heat flow path from the heating region 164, located part way up the side wall 126, to the contact surface 168 is interrupted by the thermal guard 166.

The thermal guard has a contact surface 168 shaped and sized to have an area at least as large as the cross sectional area of the substrate carrier 114, meaning that the tip 134 can fit entirely within the contact surface 168. The thermal guard 166 thus inhibits heat flow from the heating region 164 part way along the tubular side wall 126 to the contact surface 168. In the embodiment of Figure 17 the thermal guard is flush with the base 112 of the heating chamber 108. In other examples the thermal guard 166 may extend toward the open first end 110, and so not be flush with the base 112, but rather may form a platform. In this latter example, the thermal guard 166 need not have a contact surface 168 sized to have an area at least as large as the cross sectional area of the substrate carrier 114, instead resulting in an arrangement similar to that shown in the first embodiment.

Thirteenth Embodiment

Referring to Figures 18A and 18B, a heating chamber 108 according to a thirteenth embodiment is similar to (and operates in the same manner as) the heating chamber 108 of the first embodiment described with reference to Figures 1 to 6B, except where explained below, and the same reference numerals are used to refer to similar features. Figures 18A and 18B show a heating chamber 10 formed of a tubular side wall 126a, 166, 126b. The tubular side wall is formed of three sections. The proximal first section 126a comprises a heating region 164. The middle second section is a thermal guard 166. The distal third section 126b is a further section of tubular side wall. In other words the proximal 126a and distal 126b sections of tubular side wall are joined to one another via the thermal guard 166.

The third section 126b is joined to a base 112, which includes a platform 148, but in other embodiments it may be flat. The upper surface of the platform 148 faces the open first end 110 of the heating chamber 108, and acts as the contact surface 168.

The thermal guard 166 inhibits heat flow from the proximate section of tubular side wall 126a to the distal section of tubular side wall 126b. This in turn stops heat being transferred from the heating region 164 to the contact surface 168 on the base 112. This in turn reduces the flow of heat to the tip 134 of the elongate substrate carrier 114.

Note that this is another example in which the roles of the thermal guard 166 and the contact surface 168 have been decoupled from each other (similarly to the situation in the ninth and tenth embodiments). As set out above, this allows the choice of material for each of the thermal guard 166 and the contact surface 168 to be chosen to optimise the duty they are to perform.

The platform 148 also raises the tip 134 away from the base, and allowing loose material to fall from the tip 134 without impeding air flow into the tip 134.

Fourteenth Embodiment

Referring to Figure 19A, according to a fourteenth embodiment an insert 192 is provided such that the insert 192 adapted to be insertable into a heating chamber 108. The insert 192 comprises a thermal guard 166 and thus allows for an existing heating chamber 108 (which may not comprise a thermal guard 166) fixed inside an aerosol generation device 100 to be “retrofitted” so as to include a thermal guard 166. With the insert 192 inserted within a heating chamber 108, the thermal guard 166 inhibits the heat flow from the heating region 164 (see Figures 19B to 19E) of the heating chamber 108 to the contact surface 168 when the insert 192 is inserted in the heating chamber 108. In more detail, the insert 192 is arranged to slide into the heating chamber 108 and also to receive the substrate carrier 114 in the way set out above in relation to the heating chamber 108. The insert 192 may be permanently fixed into the heating chamber 108 as part of a one-time retrofitting upgrade to an existing heating chamber. Alternatively the insert 192 may be removable. For example the insert 192 may be arranged to clip into place for use in the aerosol generation device, but may be removable once the aerosol substrate 128 has been depleted. This arrangement can help remove the substrate carrier 114 after use without damaging it, as the substrate carrier 114 can be removed at the same time as the insert 192, while retained in the insert 192. Similarly, the insert 192, once removed can have a fresh substrate carrier 114 mounted into the insert 192 prior to loading both the insert 192 and the substrate carrier 114 into the heating chamber 108. Loading the substrate carrier 114 into the insert 192 prior to insertion into the heating chamber 108 may allow a user to monitor the loading process carefully, thereby reducing possible damage to the substrate carrier 114 and ensuring that the substrate carrier 114 has correctly fit into the insert 192 by visual inspection. This also allows the insert 192 to be cleaned with ease.

The arrangement in the fourteenth embodiment is similar to the arrangement described in previous embodiments except that the thermal guard is provided on an insert 192 inserted into the heating chamber 108. The insert 192 may be provided in a number of configurations, but the illustrated insert 192 is similar in structure to the fourth embodiment of the heating chamber 108 described earlier in relation to Figure 9. Differences to previous embodiments are explained below; the same reference numerals are used to refer to similar features from previous embodiments.

The exemplary insert of Figure 19A comprises a plurality of rod-shaped elements 176. In the example shown, the rods 176 are bent towards a central axis at the second end to form a base. In yet further examples, the insert side wall may be solid and the base may be formed of rods. The insert base and insert side wall may also be made of a mesh or wire net, as described in relation to the heating chamber 108 shown in Figure 10, or in any appropriate combination. It will be appreciated that numerous structures of insert 192 similar to the other described embodiments of heating chamber 108 are possible. In particular, the insert 192 may have a solid side wall, and optionally also protrusions 140.

The base of the insert 192 comprises a thermal guard 166 having an upwardly facing contact surface 168. More generally the thermal guard 166 may be provided at or proximate to the lower end of the insert 192.

The insert 192 is shown with the optional feature of a rim 107 coupled to the proximal end of the insert 192. The rim 107 is an optional feature but may have the advantage of allowing the upper end of the insert 192 to rest on, or be secured to, the upper end of the heating chamber 108 into which it is inserted (see for example Figure 19B). With the insert 192 inserted in the heating chamber a whole or part of the rim 107 may be disposed outside of the interior of the heating chamber 108 in a way that is easy for the user to access or grasp, thereby to allow removal of the insert 192 (e.g. for cleaning). The rim 107 of the insert 192 may also provide additional structural support to the side walls of the insert 192. In the illustrated example, the upper ends of the rods 176 are secured in the rim 107, thereby helping to protect the rods 176 from damage, e.g. by bending. With reference to Figure 19B and 19C it can be seen that the insert 192 is configured to have dimensions such that it may be inserted into a heating chamber, and when inserted into the heating chamber the thermal guard 166 inhibits the conduction of heat from the heating region 164 of the heating chamber to the contact surface 168 of the thermal guard 166. In Figure 19B, the insert 192 is shown being inserted into a heating chamber 108. In the illustrated example the rods 176 of the insert 192 are configured to sit flush with the side wall 126 of the heating chamber. This allows heat to transfer by conduction from the side wall 126 of the heating chamber 108 to the insert 192. The illustrated insert 192 is also configured such that the lower surface of the thermal guard 166 is in contact with the base of the heating chamber 108 with the insert 192 inserted in the heating chamber, as shown in Figure 19C.

It will be appreciated that with the rods 176 in contact with the side wall 126 of the heating chamber 108 at the heating region 164 the conduction of heat from the heating region 164 to the contact surface 168 is inhibited by the thermal guard 166. This in turn inhibits conduction of heat from the heating region 164 to the tip 134 of the substrate carrier 114. It can also be seen that where the lower surface of the thermal guard 166 of the insert is in contact with the base of the heating chamber 108 (to which heat may be conducted from the heating region 164 via the side wall 126 of the heating chamber 108) the thermal guard 166 inhibits the conduction of heat from the heating region 164 to the contact surface 168.

Further, the insert 192 is configured to receive the elongate substrate carrier 114 as shown in Figure 19C in a similar manner to previous embodiments. The illustrated insert 192 is dimensioned such that the rods 176 compress the substrate carrier when it is inserted into the insert. This may provide for an interference fit between the substrate carrier 114 and the insert 192 and improved heat conduction from the rods 176 of the insert 192 to the aerosol substrate 128. With the substrate carrier 114 inserted into the insert 192, the tip 134 of the substrate carrier 114 contacts the contact surface 168. There is an annular portion of the tip 134 of the substrate carrier 114 which is not in contact with the contact surface 168. By comparing Figures 19A and 19C, it can be seen that an air flow path exists through which air can be drawn from the exterior of the heating chamber 108 through the gaps between the rods 176 of the insert 192 and into the tip 134 of the substrate carrier 114. In alternative embodiments, the side wall of the insert 192 may be solid and in such configurations an air flow path according to the second embodiment may be appropriate. In other examples, a spacer 190 may be used as described below with reference to Figure 19E.

Figure 19D shows an aerosol generation device 100 comprising a heating chamber 108 with an insert 192 having a thermal guard 166 according to the fourteenth embodiment. The rim 107 of the insert 192 rests on the open first end 110 of the heating chamber 108 and the rods 176 which form the side wall of the insert 192 sit flush along the side wall 126 of the heating chamber. The substrate carrier 114 is inserted into the insert 192 for use, and at its tip 134 contacts the contact surface 168.

In Figure 19E an alternative insert 192 to that illustrated in Figures 19A to 19D is shown inserted into a heating chamber 108 in an aerosol generation device 100. In this example, the insert 192 has solid side walls (i.e. not formed of rods 176 as in Figures 19A to 19D) and is dimensioned such that the substrate carrier 114 is not compressed by the side walls of the insert 192 when inserted therein. In fact, there is a gap between the side walls of the insert 192 and the substrate carrier 114 maintained by means of a spacer 190 in a similar manner to that shown in Figure 8C. The spacer 190 is provided above the open first end 110 of the heating chamber 108 and is configured to hold the substrate carrier 114 within the insert 192 such that a gap is maintained between the outer layer 132 of the substrate carrier 114 and the side wall of the insert 192. The spacer 190 may be removable as set out above (Figure 8C) in order to allow insertion/removal of the insert 192 into the heating chamber. The spacer 190 may be attached to the insert 192 in some examples, to assist in this.

Alternative configurations of the insert 192 are possible, for example, in which the base or thermal guard 166 of the insert 192 are not in contact with the base of the heating chamber 108, or where the side walls (or rods 176) of the insert 192 do not sit flush to heating chamber 108 with the insert 192 inserted in the heating chamber. In this latter example, a spacer 190 can be used to ensure that the insert 192 (and the substrate carrier 114 held therein) are maintained in their intended positions, centrally within the heating chamber 108.

Definitions and Alternative Embodiments

It will be appreciated from the description above that many features of the different embodiments are interchangeable with one another. The disclosure extends to further embodiments comprising features from different embodiments combined together in ways not specifically mentioned. For example any of the thermal guard arrangements set out herein may be used with either air flow path (first and second embodiments), with minor adaptations made to the base in each case to allow air to flow into the heating chamber 108 through the base. Similarly, the rod or mesh walls of the fourth and fifth embodiments may be applied to any of the different embodiments of the thermal guard 166. The protrusions 140 for compressing the aerosol substrate provided in the first embodiment may also be provided in any of the other embodiments, with their associated advantages. Similarly inserts may be provided with features of any of the embodiments of the heating chambers disclosed herein and be dimensioned to be compatible with any appropriate heating chamber. Each heating chamber 108 may be provided with a flange or rim at the open first end 110 for structural support and optionally formed of a thermally insulating material to prevent heat leakage to the outer casing 102.

Figures 6A, 6B and 8 to 18 show the heating chamber 108 separated from the aerosol generation device 100. This is to highlight that the advantageous features described for the design of the heating chamber 108 are independent of the other features of the aerosol generation device 100. In particular, the heating chamber 108 finds many uses, not all of which are tied to the aerosol generation device 100 described herein. Such designs may benefit from protrusions for conducting heat to, and/or compressing, an aerosol substrate and/or for providing strength to the side wall 126 of such a heating chamber. Such uses are advantageously provided with the heating chamber described herein.

In addition, the heating chamber 108 shown in any embodiment may be removable from the aerosol generation device 100, for example for cleaning. In such cases, the heating region 164 would not usually be used to mount a heater 124, as making electrical connections to heaters can create complications with removable heating chambers 108. Instead, the heating chamber may have a heating region 164 which is arranged to be heated inductively, by radiation, or via combustion, for example. Where the heating chamber is removeable, the thermal guard may be positioned outside the heating chamber, for example between the walls of the cavity into which the heating chamber 108 fits and the heating chamber itself.

It will be appreciated that the thermal guards 166 and/or contact surfaces 168 in some embodiments may preferably be used with the alternative air flow path set out in the second embodiment to allow air to flow into the tip 134 of the substrate carrier 114. In other examples, the contact surface 168 may not be flat (as illustrated schematically in the Figures), but may be convex or shaped so as to extend inwardly into the heating chamber 108 to provide a platform for contacting the tip 134, which in turn can allow air flow into the tip 134.

The term “heater" should be understood to mean any device for outputting thermal energy sufficient to form an aerosol from the aerosol substrate 128. The transfer of heat energy from the heater 124 to the aerosol substrate 128 may be conductive, convective, radiative or any combination of these means. As non-limiting examples, conductive heaters may directly contact and press the aerosol substrate 128, or they may contact a separate component which itself causes heating of the aerosol substrate 128 by conduction, convection, and/or radiation. Convective heating may include heating a liquid or gas which consequently transfers heat energy (directly or indirectly) to the aerosol substrate.

Radiative heating includes, but is not limited to, transferring energy to an aerosol substrate 128 by emitting electromagnetic radiation in the ultraviolet, visible, infrared, microwave or radio parts of the electromagnetic spectrum. Radiation emitted in this way may be absorbed directly by the aerosol substrate 128 to cause heating, or the radiation may be absorbed by another material such as a susceptor or a fluorescent material which results in radiation being re-emitted with a different wavelength or spectral weighting. In some cases, the radiation may be absorbed by a material which then transfers the heat to the aerosol substrate 128 by any combination of conduction, convection and/or radiation.

Heaters may be electrically powered, powered by combustion, or by any other suitable means. Electrically powered heaters may include resistive track elements (optionally including insulating packaging), induction heating systems (e.g. including an electromagnet and high frequency oscillator), etc. The heater 128 may be arranged around the outside of the aerosol substrate 128, it may penetrate part way or fully into the aerosol substrate 128, or any combination of these.

The term “temperature sensor” is used to describe an element which is capable of determining an absolute or relative temperature of a part of the aerosol generation device 100. This can include thermocouples, thermopiles, thermistors and the like. The temperature sensor may be provided as part of another component, or it may be a separate component. In some examples, more than one temperature sensor may be provided, for example to monitor heating of different parts of the aerosol generation device 100, e.g. to determine thermal profiles.

With reference to the above-described embodiments, aerosol substrate 128 includes tobacco, for example in dried or cured form, in some cases with additional ingredients for flavouring or producing a smoother or otherwise more pleasurable experience. In some examples, the aerosol substrate 128 such as tobacco may be treated with a vaporising agent. The vaporising agent may improve the generation of aerosol from the aerosol substrate. The vaporising agent may include, for example, a polyol such as glycerol, or a glycol such as propylene glycol. In some cases, the aerosol substrate may contain no tobacco, or even no nicotine, but instead may contain naturally or artificially derived ingredients for flavouring, volatilisation, improving smoothness, and/or providing other pleasurable effects. The aerosol substrate 128 may be provided as a solid or paste type material in shredded, pelletised, powdered, granulated, strip or sheet form, optionally a combination of these. Equally, the aerosol substrate 128 may be a liquid or gel. Indeed, some examples may include both solid and liquid/gel parts.

Consequently, the aerosol generation device 100 could equally be referred to as a “heated tobacco device”, a “heat-not-burn tobacco device”, a “device for vaporising tobacco products”, and the like, with this being interpreted as a device suitable for achieving these effects. The features disclosed herein are equally applicable to devices which are designed to vaporise any aerosol substrate. The embodiments of the aerosol generation device 100 are described as being arranged to receive the aerosol substrate 128 in a pre-packaged substrate carrier 114. The substrate carrier 114 may broadly resemble a cigarette, having a tubular region with an aerosol substrate arranged in a suitable manner. Filters, aerosol collection regions, cooling regions, and other structure may also be included in some designs. An outer layer of paper or other flexible planar material such as foil may also be provided, for example to hold the aerosol substrate in place, to further the resemblance of a cigarette, etc.

As used herein, the term “fluid” shall be construed as generically describing non-solid materials of the type that are capable of flowing, including, but not limited to, liquids, pastes, gels, powders and the like. “Fluidized materials” shall be construed accordingly as materials which are inherently, or have been modified to behave as, fluids. Fluidization may include, but is not limited to, powdering, dissolving in a solvent, gelling, thickening, thinning and the like.

As used herein, the term “volatile” means a substance capable of readily changing from the solid or liquid state to the gaseous state. As a non-limiting example, a volatile substance may be one which has a boiling or sublimation temperature close to room temperature at ambient pressure. Accordingly “volatilize” or “volatilise” shall be construed as meaning to render (a material) volatile and/or to cause to evaporate or disperse in vapour.

As used herein, the term “vapour” (or “vapor”) means: (i) the form into which liquids are naturally converted by the action of a sufficient degree of heat; or (ii) particles of liquid/moisture that are suspended in the atmosphere and visible as clouds of steam/smoke; or (iii) a fluid that fills a space like a gas but, being below its critical temperature, can be liquefied by pressure alone.

Consistently with this definition the term “vaporise” (or “vaporize”) means: (i) to change, or cause the change into vapour; and (ii) where the particles change physical state (i.e. from liquid or solid into the gaseous state).

As used herein, the term “atomise” (or “atomize”) shall mean: (i) to turn (a substance, especially a liquid) into very small particles or droplets; and (ii) where the particles remain in the same physical state (liquid or solid) as they were prior to atomization.

As used herein, the term “aerosol” shall mean a system of particles dispersed in the air or in a gas, such as mist, fog, or smoke. Accordingly the term “aerosolise” (or “aerosolize”) means to make into an aerosol and/or to disperse as an aerosol. Note that the meaning of aerosol/aerosolise is consistent with each of volatilise, atomise and vaporise as defined above. For the avoidance of doubt, aerosol is used to consistently describe mists or droplets comprising atomised, volatilised or vaporised particles. Aerosol also includes mists or droplets comprising any combination of atomised, volatilised or vaporised particles.

Claims

1. A heating chamber (108) for an aerosol generation device (100), which aerosol generation device (100) has a heater (124) positioned externally of the heating chamber (108), the heating chamber (108) being for receiving an elongate substrate carrier (114) having an aerosol substrate (128) arranged towards a first end (134) of the elongate substrate carrier (114) and the heating chamber (108) comprising: a tubular side wall (126) defining an interior volume and having a first end (110), through which first end (110) the elongate substrate carrier (114) is receivable into the interior volume and air can flow towards the aerosol substrate (128), and a second end (111) distal to the first end (110); a heating region (164) via which heat from the externally positioned heater (124) is applied to the heating chamber (108); a contact surface (168) exposed to the interior volume for contacting the substrate carrier (114) at or proximate to the second end of the interior volume; and a thermal guard (166) at the second end (111) for inhibiting heat flow from the heating region (164) to the at least one contact surface (168).

2. The heating chamber (108) of claim 1, wherein the at least one contact surface (168) faces the first end (110) of the tubular side wall (126).

3. The heating chamber (108) of claim 1 or claim 2, wherein the thermal guard (166) comprises a first material and the tubular side wall (126) comprises a second material, the first material having a lower thermal conductivity than the second material.

4. The heating chamber (108) of claim 3, wherein the thermal guard is made of ceramic and/or the tubular side wall is made of metal.

5. The heating chamber (108) of any one of the preceding claims, wherein the at least one contact surface (168) is a surface of the thermal guard (166).

6. The heating chamber (108) of any one of the preceding claims, wherein the thermal guard (166) is annular.

7. The heating chamber (108) of any one the preceding claims, wherein the thermal guard (166) is a separate element attached to the tubular side wall (126).

8. The heating chamber (108) of any one of the preceding claims, wherein the contact surface (168) extends from the tubular side wall (126) into the interior volume.

9. The heating chamber (108) of any one of the preceding claims, further comprising a base (112) at the second end (111) of the tubular side wall (126).

10. The heating chamber (108) of claim 9, wherein the heating region (164) comprises a part of the base (112).

11. The heating chamber (108) of any one of claims 1 to 9, wherein the heating region (164) comprises a part of the tubular side wall (108).

12. The heating chamber (108) of claim 9 or claim 10, wherein the thermal guard (166) comprises a part of the base (112).

13. The heating chamber (108) of claim 12, wherein the thermal guard (166) extends inwardly from the base (112) towards the interior volume to provide a platform for supporting the substrate carrier (114).

14. The heating chamber (108) of claim 12 or claim 13, wherein the thermal guard (166) extends across a full width of the base (112).

15. The heating chamber (108) of any one of claims 12 to 14, wherein the thermal guard (166) is a separate element attached to the base (112).

16. The heating chamber (108) of any preceding claim, further comprising an insert (192) comprising the thermal guard (166), wherein the insert (192) is arranged for removable insertion into the interior volume of the heating chamber (108).

17. The heating chamber (108) of claim 16, wherein the insert comprises a mesh or wire net or a plurality of rod-shaped elements.

18. An aerosol generation device (100) comprising the heating chamber (108) of any one of the preceding claims and the heater (124), wherein the heater (124) is mounted to the tubular side wall (126) and the heating region (164) is defined by a region of the tubular side wall (126) at least partially overlapped by the heater (124).

19. The aerosol generation device (100) of claim 18, wherein the heater (124) is mounted on a surface of the tubular side wall (126) facing away from the interior volume.

20. The aerosol generation device (100) of claim 18 or claim 19, comprising: an electrical power source (120); and control circuitry (122) configured to control supply of electrical power from the electrical power source to the heater (124).

21. The aerosol generation device (100) of any one of claims 18 to 20, further comprising a spacer (190) for retaining the substrate carrier (114) in a central configuration within the heating chamber (108).

22. The aerosol generation device (100) of claim 21 , wherein the spacer (190) is releasably coupled to the aerosol generation device (100).

23. An aerosol generation system comprising the aerosol generation device (100) of any one of claims 18 to 22 and the substrate carrier (114).