Aerosol-generating article comprising a tubular element having at least two airflow channels - Patents.com

Abstract

An aerosol-generating article having an upstream end and a downstream end, the aerosol-generating article comprising: an aerosol-forming substrate; a tubular element arranged downstream of the aerosol-forming substrate and extending along a longitudinal direction, the tubular element comprising an inner tube and an outer tube, the outer tube being arranged around the inner tube, an outer airflow channel being longitudinally bounded by the inner tube and the outer tube, the inner airflow channel being longitudinally bounded by the inner tube, and at least the inner airflow channel being adapted for the substrate aerosol to flow towards the downstream end, a flavor substrate arranged downstream of the aerosol-forming substrate, and at least one permeable control element arranged in the outer airflow channel.

Description

[Technical field]

[0001] The present invention relates to an aerosol-generating article that includes an aerosol-forming substrate for generating an inhalable aerosol upon heating. [Background technology]

[0002] Aerosol-generating articles in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. The purpose of such heated aerosol-generating articles is to reduce the potentially harmful by-products produced by the combustion and thermal decomposition of tobacco in conventional cigarettes. Summary of the Invention [Problem to be solved by the invention]

[0003] In heated aerosol-generating articles, inhalable aerosols are typically generated by heat transfer from a heater to an aerosol-forming substrate. During heating, volatile compounds are released from the aerosol-forming substrate and entrained in the air. For example, volatile compounds may be entrained in air that passes through, passes around, or is otherwise drawn into the vicinity of the aerosol-generating article. As the released volatile compounds cool, they condense to form an aerosol. The aerosol can be inhaled by a user. The aerosol can contain aromas, flavors, nicotine, and other desirable elements.

[0004] The heating element may be included in an aerosol generating device. The combination of the aerosol generating article and the aerosol generating device may form an aerosol generating system.

[0005] The heated aerosol-generating article may include a flavor substrate in addition to the aerosol-forming substrate. Heat transfer from the heater to the flavor substrate causes volatile compounds to be released from the flavor substrate and entrained in the air. As the released volatile compounds cool, they condense to form an aerosol that may contain fragrances, flavors, nicotine, and other desired elements. The aerosol formed from the flavor substrate may be entrained in the aerosol formed from the aerosol-forming substrate. The resulting mixed aerosol may be inhaled by the user.

[0006] It is therefore desirable to provide an aerosol-generating article, wherein a mixed aerosol formed from an aerosol-forming substrate and from a separate flavour substrate is generated in an efficient manner. [Brief description of the drawings]

[0007] [Figure 1] 1 shows a longitudinal cross-section of an aerosol-generating article in which a tubular element comprises an inner airflow channel and an outer airflow channel. [Diagram 2] 2 shows the aerosol-generating article of FIG. 1 at the moment when the aerosol-forming substrate and flavor substrate are heated to release an aerosol, where the spanning element, flavor substrate and permeability control element are fluid permeable. [Diagram 3] 1 depicts a longitudinal cross-sectional view of an aerosol-generating article in which a flavor substrate is disposed within the outer airflow channel of a tubular element. [Figure 4] 4 depicts the aerosol-generating article of FIG. 3 at the moment when the aerosol-forming substrate and flavor substrate are heated to release an aerosol, wherein the spanning element, flavor substrate and permeability control element are fluid permeable. [Diagram 5] A longitudinal cross-section of the aerosol-generating article is shown in which the flavor substrate is the only permeable control element downstream of the air inlet in the outer airflow channel. [Figure 6] 6 depicts the aerosol-generating article of FIG. 5 at the moment when the aerosol-forming substrate and flavor substrate are heated to release an aerosol, the spanning element and flavor substrate being fluid permeable. [Figure 7]1 depicts a longitudinal cross-sectional view of an aerosol-generating article in which the outer airflow channel does not include an air inlet. [Figure 8] 8 depicts the aerosol-generating article of FIG. 7 at the moment when the aerosol-forming substrate and flavor substrate are heated to release an aerosol, wherein the spanning element, flavor substrate and permeability control element are fluid permeable. [Figure 9] 1 shows a longitudinal cross-sectional view of an aerosol-generating article in which the flavor substrate occupies the entire length of the outer airflow channel. [Figure 10] 10 depicts the aerosol-generating article of FIG. 9 at the moment when the aerosol-forming substrate and the flavor substrate are heated to release an aerosol, the flavor substrate being fluid permeable. [Figure 11] 1 shows a longitudinal cross-sectional view of an aerosol generating system including an aerosol generating article and an aerosol generating device. [Figure 12] 12 depicts a housing of the aerosol generating device of FIG. 11 receiving an aerosol-generating article. [Figure 13] FIG. 13 shows a perspective view of the aerosol generating device of FIGS. 11 and 12. [Figure 14] FIG. 2 shows a perspective view of a downstream induction heating device. [Figure 15] FIG. 2 is an exploded view of the downstream induction heating device of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An aerosol-generating article may be provided. The aerosol-generating article may have an upstream end and a downstream end, the aerosol-generating article defining a longitudinal direction between the upstream end and the downstream end. The aerosol-generating article may include an aerosol-forming substrate. The aerosol-generating article may comprise a tubular element arranged downstream of the aerosol-forming substrate and extending along the longitudinal direction. The tubular element may comprise an inner tube and an outer tube, the outer tube being arranged around the inner tube. The outer airflow channel may be bounded longitudinally by the inner tube and the outer tube. The inner airflow channel may be bounded longitudinally by the inner tube. The at least one inner airflow channel may be adapted for substrate aerosol to flow towards the downstream end. The flavour substrate may be arranged downstream of the aerosol-forming substrate. The aerosol-generating article may comprise at least one permeable control element. The permeable control element may comprise a flavour substrate or may be a flavour substrate. The at least one permeable control element may be configured to be fluid permeable when the temperature of the at least one permeable control element is equal to or higher than the permeability transition temperature of the at least one permeable control element. The at least one permeable control element may be configured to be substantially fluid impermeable when the temperature of the at least one permeable control element is lower than the permeability transition temperature of the at least one permeable control element. The at least one permeable control element may be disposed within the outer airflow channel. The at least one permeable control element may be configured to prevent fluid from flowing along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is lower than the permeability transition temperature of the at least one permeable control element. The at least one permeable control element may be configured to allow fluid to flow along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is equal to or higher than the permeability transition temperature of the at least one permeable control element. The at least one permeable control element can be configured to prevent fluid from flowing along the outer airflow channel downstream of the at least one permeable control element when the temperature of the at least one permeable control element is 20 degrees Celsius.The at least one permeable control element can be configured to allow fluid to flow along the outer airflow channel downstream of the at least one permeable control element when the temperature of the at least one permeable control element is 85 degrees Celsius.

[0009] An aerosol-generating article may be provided, the aerosol-generating article having an upstream end and a downstream end, the aerosol-generating article defining a longitudinal direction between the upstream end and the downstream end, the aerosol-generating article comprising: an aerosol-forming substrate; a tubular element arranged downstream of the aerosol-forming substrate and extending along a longitudinal axis, the tubular element comprising an inner tube and an outer tube, the outer tube being arranged around the inner tube, an outer airflow channel being bounded longitudinally by the inner tube and the outer tube, the inner airflow channel being bounded longitudinally by the inner tube, and at least the inner airflow channel being adapted to flow the substrate aerosol towards a downstream end; a flavour substrate disposed downstream of the aerosol-forming substrate; At least one permeability control element; the at least one permeability control element is configured to be fluid permeable when a temperature of the at least one permeability control element is equal to or greater than a permeability transition temperature of the at least one permeability control element; the at least one permeability control element is configured to be substantially fluid impermeable when a temperature of the at least one permeability control element is below a permeability transition temperature of the at least one permeability control element; At least one permeability control element is disposed within the outer airflow channel, and the at least one permeability control element is configured to prevent fluid from flowing along the outer airflow channel downstream of the permeability control element when a temperature of the at least one permeability control element is lower than a permeability transition temperature of the at least one permeability control element, and to allow fluid to flow along the outer airflow channel downstream of the permeability control element when a temperature of the at least one permeability control element is equal to or higher than the permeability transition temperature of the at least one permeability control element.

[0010] As used herein, the term "tubular element" is used to mean a generally elongated element that defines a lumen or airflow channel along its longitudinal axis. In particular, the term "tubular" is used hereinafter with reference to a tubular element that has a substantially cylindrical cross-section and defines at least one airflow channel that establishes uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it will be appreciated that alternative shapes (e.g., alternative cross-sectional shapes) of the tubular element may be possible.

[0011] As used herein, the term "elongated" means that an element has a length dimension that is greater than its width or diameter dimension, e.g., more than twice its width or diameter dimension.

[0012] The term "aerosol-generating article" is used herein to mean an article in which an aerosol-forming substrate is heated to generate an inhalable aerosol for delivery to a consumer. As used herein, the term "aerosol-forming substrate" relates to a substrate capable of releasing volatile compounds capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol-forming substrate is typically part of the aerosol-generating article.

[0013] The aerosol-forming substrate may comprise nicotine. The nicotine-containing aerosol-forming substrate may be a nicotine salt matrix.

[0014] The aerosol-forming substrate may be a liquid. The aerosol-forming substrate may comprise a solid component and a liquid component. The aerosol-forming substrate is preferably a solid.

[0015] The aerosol-forming substrate may comprise a plant-derived material. The aerosol-forming substrate may comprise tobacco. The aerosol-forming substrate may comprise a tobacco-containing material comprising volatile tobacco flavour compounds which are released from the aerosol-forming substrate upon heating. The aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may comprise a homogenised plant-derived material.

[0016] As used herein, the term "aerosol-generating device" refers to a device that includes a heater that interacts with an aerosol-forming or flavor substrate of an aerosol-generating article to generate an aerosol.

[0017] As used herein in connection with the present invention, the term "rod" is used to denote a generally cylindrical element of substantially circular, oval or elliptical cross section.

[0018] The term "longitudinal" as used herein refers to a direction corresponding to a major longitudinal axis of the aerosol-generating article extending between the upstream and downstream ends of the aerosol-generating article. The terms "upstream" and "downstream" as used herein describe the relative positions of an element (or portion of an element) of the aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

[0019] In use, air is drawn longitudinally through the aerosol-generating article. The term "transverse" refers to a direction perpendicular to the longitudinal axis. Any reference to a "cross section" of an aerosol-generating article or a component of an aerosol-generating article refers to a transverse cross section, unless otherwise specified.

[0020] The term "length" refers to the dimension of a component of an aerosol-generating article in its longitudinal direction. For example, it may be used to refer to the dimension of a rod or elongated tubular element in its longitudinal direction.

[0021] The term "flavor substrate" as used herein relates to a substrate, separate from the aerosol-forming substrate, capable of releasing volatile compounds capable of forming an aerosol. Such volatile compounds may be released by heating the flavor substrate.

[0022] As used herein, the "permeability transition temperature" of a material is the temperature at which the permeability of the material changes dramatically upon heating or cooling. It can be established that at temperatures below the permeability transition temperature, the material is substantially impermeable to fluids, and at temperatures above the permeability transition temperature, the material is permeable to fluids.

[0023] The permeability transition temperature of a material may be the phase transition temperature of the material. When heated to the phase transition temperature, the material may change phase from solid to liquid. When cooled to the phase transition temperature, the material may change phase from liquid to solid.

[0024] The use of a flavour substrate to generate an aerosol upon heating may be desirable to generate a uniform and highly consistent flavour aerosol that is entrained in the substrate aerosol generated by an aerosol-forming substrate located upstream of the flavour substrate.

[0025] Similarly, the provision of an inner airflow channel and an outer airflow channel in the tubular element may allow the presence of at least two independent airflow paths in the tubular element. The inner airflow channel is usually adapted to allow the substrate aerosol generated upon heating of the aerosol-forming substrate to flow towards the downstream end. The outer airflow path may be used to regulate the overall amount of airflow flowing along the tubular element. In particular, at least one permeable control element may be disposed in the outer airflow channel. The at least one permeable control element may be configured to prevent fluid from flowing along the outer airflow channel downstream of the at least one permeable control element when its temperature is below its permeability transition temperature, and to allow fluid to flow along the outer airflow channel downstream of the at least one permeable control element when its temperature is equal to or higher than its permeability transition temperature.

[0026] Therefore, providing a flavor substrate inside or downstream of the tubular element can be beneficial in that the flavor substrate can regulate the amount of airflow provided, which can allow customization of the aerosol generated by the flavor substrate, which can also improve the concentration of the aerosol generated by the flavor substrate upon heating.

[0027] Additionally, changes in the temperature of the at least one permeability control element can be utilized to provide greater control over the overall resistance to draw (RTD) of the aerosol-generating article. In particular, the at least one permeability control element can be advantageously used to enable a potential reduction in RTD due to changes in the permeability of the at least one permeability control element during use.

[0028] The tubular element preferably defines at least one airflow channel that establishes uninterrupted fluid communication between an upstream position within the tubular element and a downstream position within the tubular element. The tubular element preferably defines at least one airflow channel that establishes uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. The flavor substrate is preferably configured to allow fluid flowing along the at least one airflow channel to flow downstream of the flavor substrate when the temperature of the flavor material is equal to or higher than the permeability transition temperature of the flavor material. The flavor substrate is preferably configured to prevent fluid flowing along the at least one airflow channel from flowing downstream of the flavor substrate when the temperature of the flavor material is lower than the permeability transition temperature of the flavor material.

[0029] To allow the airflow to flow towards the downstream end, the flavour substrate may not extend across the entire cross section of the airflow channel.

[0030] Alternatively, the flavor substrate may block the airflow channel. The flavor substrate may extend across the entire cross-section of one or more of the airflow channels to block airflow towards the downstream end. Thus, the flavor substrate may extend across about 100 percent of the cross-section of the airflow channel. The flavor substrate may extend across at least about 25 percent of the cross-section of the airflow channel. The flavor substrate may extend across at least about 50 percent of the cross-section of the airflow channel. The flavor substrate may extend across at least about 75 percent of the cross-section of the airflow channel.

[0031] For at least the reasons stated above, at least one transparency control element may improve customization of the user experience.

[0032] The outer airflow channel may also be adapted to allow the substrate aerosol generated upon heating of the aerosol-forming substrate to flow towards the downstream end.

[0033] The at least one permeable control element may be configured to prevent fluid from flowing along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is at least 20 degrees Celsius, and to allow fluid to flow along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is at least 85 degrees Celsius.

[0034] A permeable control element that is substantially fluid impermeable at 20 degrees Celsius and fluid permeable at 85 degrees Celsius may be desirable to achieve regulation of airflow in the outer airflow channel using an aerosol generating device.

[0035] The permeability transition temperature of the at least one permeability control element may be between 70 degrees Celsius and 80 degrees Celsius.

[0036] The flavour substrate may be located within the outer airflow channel, which may be advantageous in that the flavour substrate may be configured to regulate the airflow within the outer airflow channel, which may also provide enhanced control over the airflow through which the flavour substrate is provided.

[0037] The flavour substrate may be a permeable control element. The flavour substrate may be a permeable control element. The permeable control element may be a flavour substrate. This may allow for an optimised design of the aerosol-generating article, in which the flavour substrate also contributes to regulating the airflow in the outer airflow channel. The aerosol-generating article may comprise only one permeable control element. When the aerosol-generating article comprises only one permeable control element, the flavour substrate may be the only permeable control element.

[0038] The aerosol-generating article may include a plurality of permeability control elements. When the aerosol-generating article includes a plurality of permeability control elements, the flavor substrate may be one of the plurality of permeability control elements. When the aerosol-generating article includes a plurality of permeability control elements, the permeability transition temperatures of the plurality of permeability control elements may be substantially the same temperature. Similarly, when the aerosol-generating article includes a plurality of permeability control elements, the plurality of permeability control elements may have different permeability transition temperatures relative to one another.

[0039] The permeable control element may be located downstream of the flavor substrate. This configuration may be beneficial to allow control of the amount of flavor aerosol entrained in the substrate aerosol generated upon heating of the aerosol-forming substrate.

[0040] The permeability transition temperature of the at least one permeability control element may be a phase transition temperature of the at least one permeability control element. When heated to the phase transition temperature, the at least one permeability control element may change phase from solid to liquid. When cooled to the phase transition temperature, the at least one permeability control element may change phase from liquid to solid.

[0041] The change in permeability between the solid and liquid states of the at least one permeable control element may be advantageously utilized to achieve regulation of airflow within the outer airflow channel.

[0042] At least one permeability control element may include a gel composition. The gel composition of the at least one permeability control element may be according to any gel composition described herein. The gel composition of the at least one permeability control element may be according to any gel composition described herein, but without nicotine or flavoring. The gel composition of the at least one permeability control element that is not a flavor substrate may be according to any gel composition described herein, but without nicotine or flavoring.

[0043] The gel composition may be useful for providing at least one permeability control element that has a required change in permeability as a function of temperature.

[0044] However, other materials different from the gel composition that also exhibit a change in permeability as a function of temperature may be used.

[0045] The gel composition or material may be thermoreversible.

[0046] As used herein, "thermoreversible" refers to a material, such as a gel composition, whose properties (particularly permeability) can be restored to an original state by heating or cooling the material to a temperature corresponding to such original state. In particular, if the material is at a first temperature below its permeability transition temperature such that it has a first permeability at which it is substantially fluid impermeable, then it is heated above its permeability transition temperature to reach a second permeability at which it is fluid permeable, and finally, when the material is cooled to the first temperature, the permeability of the material is substantially restored to the first permeability. Similarly, if the material is at a first temperature above its permeability transition temperature such that it has a first permeability at which it is fluid permeable, then it is cooled below its permeability transition temperature to reach a second permeability at which it is substantially fluid impermeable, and finally, when the material is heated to the first temperature, the permeability of the material is substantially restored to the first permeability.

[0047] Advantageously, by providing a thermoreversible material, such as a thermoreversible gel, an aerosol-generating device may be configured to repeatedly change the properties of the aerosol-generating article during use, such as the resistance to withdrawal, the amount of airflow within the article, or the amount of aerosol generated upon heating of the flavour substrate. In particular, the properties of the aerosol-generating article may be reverted to their original state.

[0048] The spanning element may be positioned in the outer airflow channel upstream of the flavor substrate.

[0049] The spanning element can be useful for regulating or impeding the flow of the substrate aerosol into the outer airflow channel.

[0050] The spanning element may be a permeability control element.

[0051] Where the spanning element is a permeable control element, regulation of the flow of the substrate aerosol into the outer airflow channel may advantageously be achieved by varying the permeability of the spanning element.

[0052] The flavor substrate may extend longitudinally along the entire outer airflow channel, which allows for controlled regulation of airflow along the outer airflow channel and regulates the flow of substrate aerosol into the outer airflow channel, making the flavor substrate more versatile.

[0053] The aerosol-generating article may include an air inlet configured to allow the intake of outside air into the outer airflow channel.

[0054] Where the outer airflow channel includes an air inlet, the outer airflow channel may advantageously be utilized to regulate the flow of outside air to the aerosol-generating article, which may allow for enhanced customization of the aerosol inhalable by the user.

[0055] The air inlet may be located downstream of the spanning element.

[0056] By locating the air inlet downstream of the spanning element, the outer airflow channel can be configured to selectively or permanently impede the flow of substrate aerosol into the outer airflow channel. Thus, the outer airflow channel may be configured to exclusively regulate the intake of outside air into the aerosol-generating article, and if a flavor element is located within the outer airflow channel, the flow of flavor aerosol will flow along the outer airflow channel, independent of the flow of substrate aerosol.

[0057] When the spanning element is a permeable control element, the substrate aerosol may be forced into the outer airflow channel, which may contribute to improved mixing of the flavor aerosol, the substrate aerosol, and ambient air to generate an aerosol that can be inhaled by the user.

[0058] The flavour substrate may be located downstream of the air inlet.

[0059] Providing a flavor substrate downstream of the air inlet included in the tubular element can be beneficial to control the amount of airflow provided to the flavor substrate, which can allow customization of the aerosol generated by the flavor substrate, which can also improve the concentration of the flavor aerosol generated by the flavor substrate upon heating.

[0060] The tubular element may be positioned immediately downstream of the aerosol-forming substrate.

[0061] This configuration, in which no intermediate part is arranged between the aerosol-forming substrate and the tubular element, can be beneficial for ensuring that the substrate aerosol generated upon heating of the aerosol-forming substrate is more efficiently entrained by the flavour aerosol generated upon heating of the flavour substrate.

[0062] The resistance to draw of the aerosol-generating article when the temperature of the at least one permeable control element is equal to or higher than the permeability transition temperature of the at least one permeable control element may be at least about 10 mmH2O greater than the resistance to draw of the aerosol-generating article when the temperature of the at least one permeable control element is lower than the permeability transition temperature of the at least one permeable control element.

[0063] As discussed above, the permeability of the at least one permeable control element can be changed by cooling or heating the at least one permeable control element to an appropriate temperature. In particular, the at least one permeable control element can be fluid permeable when heated to its permeability transition temperature. This can allow for variation in the resistance to withdrawal of the aerosol-generating article, which can be easily achieved and determined. Advantageously, a difference of at least about 10 mmH2O between the resistance to withdrawal of the aerosol-generating article when the temperature of the at least one permeable control element is equal to or higher than its permeability transition temperature with respect to the resistance to withdrawal of the aerosol-generating article when the temperature of the at least one permeable control element is lower than its permeability transition temperature can result in a significant change in the user's experience.

[0064] More preferably, the resistance to withdrawal of the aerosol-generating article when the temperature of the at least one permeable control element is equal to or higher than the permeability transition temperature of the at least one permeable control element may be at least about 20 mmH2O greater than the resistance to withdrawal of the aerosol-generating article when the temperature of the at least one permeable control element is lower than the permeability transition temperature of the at least one permeable control element. Even more preferably, the resistance to withdrawal of the aerosol-generating article when the temperature of the at least one permeable control element is equal to or higher than the permeability transition temperature of the at least one permeable control element may be at least about 30 mmH2O greater than the resistance to withdrawal of the aerosol-generating article when the temperature of the at least one permeable control element is lower than the permeability transition temperature of the at least one permeable control element.

[0065] When the temperature of the at least one permeable control element is below the permeability transition temperature of the at least one permeable control element, the resistance to withdrawal of the aerosol-generating article may be greater than about 20 mmH2O, even more preferably greater than about 30 mmH2O, even more preferably greater than about 40 mmH2O, even more preferably greater than about 50 mmH2O, and most preferably greater than about 60 mmH2O.

[0066] When the temperature of the at least one permeable control element is equal to or greater than the permeability transition temperature of the at least one permeable control element, the resistance to draw of the aerosol-generating article may be less than about 50 mmH2O, even more preferably less than about 40 mmH2O, even more preferably less than about 30 mmH2O, even more preferably less than about 20 mmH2O, and most preferably less than about 10 mmH2O.

[0067] The distance between the upstream end of the aerosol-forming substrate and the downstream end of the flavour substrate may be less than about 40 millimetres, preferably less than about 30 millimetres, even more preferably less than 20 millimetres.

[0068] A distance between the upstream end of the aerosol-forming substrate and the downstream end of the flavour substrate within such a range may be beneficial for generating a more consistent aerosol when the substrate aerosol generated upon heating of the aerosol-forming substrate and the flavour aerosol generated upon heating of the flavour substrate blend form an aerosol inhalable by a user.

[0069] The tubular element may have a length of from about 3.9 mm to about 8 mm, preferably from about 4.4 mm to about 7.8 mm.

[0070] The ratio between the length of the tubular element and the length of the aerosol-generating article may be from about 0.2 to about 0.45, more preferably from about 0.25 to 0.35.

[0071] A tubular element having such a length, or such a relative length compared to the length of the aerosol-generating article, may also improve mixing of the substrate aerosol generated upon heating of the aerosol-forming substrate, the flavor aerosol generated upon heating of the flavor substrate, and ambient air drawn into the tubular element through the air inlet.

[0072] The aerosol-generating article may include an adjustment member disposed on the tubular element and movable relative to the tubular element such that the adjustment member is configured to vary the size of the air inlet.

[0073] Providing an adjustment member to vary the size of the air inlet can be advantageous in controlling the amount of airflow within the aerosol-generating article during use. The adjustment member can be used in conjunction with at least one permeable control element to adjust the amount of airflow within the aerosol-generating article during use. This can allow for more versatility in adjusting airflow within the aerosol-generating article.

[0074] The adjustment member and the tubular element may be linearly movable relative to one another. The adjustment member and the tubular element may be configured to rotate relative to one another. The adjustment member and the tubular element may be configured to rotate and move linearly relative to one another, for example, by a screw thread.

[0075] The flavour substrate may comprise a flavour material, such as a gel composition.

[0076] The use of a flavor substrate comprising a flavor material to generate an aerosol upon heating may be desirable as it provides a uniform substrate capable of generating a highly consistent aerosol that is entrained in the aerosol generated by an aerosol-forming substrate located upstream of the flavor substrate.

[0077] When the flavor substrate comprises a flavorant, the flavorant may be configured to be fluid permeable when the temperature of the flavorant is equal to or greater than the permeability transition temperature of the flavorant, and the flavorant may be configured to be substantially fluid impermeable when the temperature of the flavorant is less than the permeability transition temperature of the flavorant.

[0078] The permeability transition temperature may be a phase transition temperature such that when the flavor substrate is heated to the phase transition temperature of the flavor material, the flavor material may change phase from a solid gel to a liquid, and when the flavor substrate is cooled to the phase transition temperature of the gel composition, the flavor material may change phase from a liquid to a solid gel.

[0079] When the flavor substrate comprises such flavor materials with varying permeability, the properties of the gel composition may be beneficial to provide greater control over the overall resistance to withdrawal (RTD) of the aerosol-generating article. In particular, the flavor substrate may be advantageously used to allow for a potential reduction in RTD due to changes in the permeability of the gel composition during use.

[0080] Similarly, the flavour substrate can be used to vary the airflow within the aerosol-generating article depending on the change in permeability of the flavour material during use, which can be particularly useful when the flavour substrate is located within the outer airflow channel.

[0081] The flavorant may be configured to be fluid permeable at 85 degrees Celsius. The flavorant may be configured to be substantially fluid impermeable at 20 degrees Celsius.

[0082] The flavouring material may comprise a gel composition, which may be advantageous in that it may result in a particularly uniform and highly consistent flavour aerosol that is entrained in the substrate aerosol generated by an aerosol-forming substrate disposed upstream of the flavour substrate.

[0083] The permeability transition temperature of a material may be the phase transition temperature of the material. When heated to the phase transition temperature, the material may change phase from solid to liquid. When cooled to the phase transition temperature, the material may change phase from liquid to solid.

[0084] When the flavor substrate comprises a gel composition, the permeability transition temperature of the gel composition may be the phase transition temperature of the gel composition, such that when the flavor substrate is heated to the phase transition temperature, the gel composition may change phase from a solid gel to a liquid, and when the flavor substrate is cooled to the phase transition temperature, the gel composition may change phase from a liquid to a solid gel.

[0085] The gel composition may be configured to be fluid permeable at 85 degrees Celsius. The gel composition may be configured to be substantially fluid impermeable at 20 degrees Celsius.

[0086] The permeability transition temperature of the flavour material, such as the gel composition, may be between 70 degrees Celsius and 80 degrees Celsius.

[0087] A permeability transition temperature of 70° C. to 80° C. may be advantageous in that this temperature may be easily reached by heating the flavor substrate in the aerosol-generating device, which may facilitate the change in properties of the aerosol-generating article during use.

[0088] The flavouring material may be thermoreversible.The gel composition may be thermoreversible.

[0089] The flavouring material, such as the gel composition, may preferably comprise an alkaloid compound selected from the group consisting of nicotine, anatabine, and combinations thereof.

[0090] Flavoring materials such as gel compositions may include nicotine in an amount of about 0.1% to about 4%, preferably about 0.1% to about 2% nicotine.

[0091] The term "nicotine" refers to nicotine and nicotine derivatives, such as free base nicotine, nicotine salts, and the like.

[0092] The flavoring material, such as the gel composition, may include a flavoring agent. The flavoring agent may include a coffee derivative flavoring agent containing menthol, caffeine, guarana, taurine, glucuronolactone, or any combination thereof. The flavoring agent may include a menthol extract. The menthol extract has at least about 55 percent menthol (C 10 H 20 The flavoring agent may include vanilla extract. The vanilla extract may have at least about 20 percent vanillin (C8H8O3). The flavoring material, such as the gel composition, may include about 0.2% to 4% flavoring agent, preferably about 0.4 to 2%.

[0093] Flavoring materials such as gel compositions may contain glycerin, the amount of glycerin being about 50% to about 75%, preferably about 50% to about 65%.

[0094] The flavoring material, such as the gel composition, may contain hydroxypolymethylcellulose (HPMC). The amount of HPMC may be about 15% to about 35%, preferably about 18% to about 32%, more preferably about 20% to about 30%, more preferably about 21% to about 27%.

[0095] The flavoring material, such as the gel composition, may contain agar, the amount of which may be about 3% to about 10%, preferably about 4% to about 7%.

[0096] The flavoring material, such as the gel composition, may include fiber. The amount of fiber may be about 0.1% to about 12%, preferably about 0.1% to 7%. The fiber may include cellulose fiber. The fiber may have a length of at least about 8 micrometers. The fiber may have a length of less than about 15 micrometers. The fiber may have a length of about 8 micrometers to about 15 micrometers.

[0097] The flavoring material, such as the gel composition, may include low methoxyl (E440i) pectin. The amount of low methoxyl (E440i) pectin may be from about 0.1% to about 9%, preferably from about 0.1% to 7%.

[0098] The flavoring material, such as the gel composition, may contain lactic acid. The amount of lactic acid may be about 1.7% to about 3.1%, preferably about 2.1% to about 2.9%.

[0099] Flavoring materials such as gel compositions may include calactate (calcium lactate). The amount of calactate may be from about 0.1% to about 7%, preferably from about 0.1% to about 3%.

[0100] The amounts above are given in weight percent. It is preferred that the amounts in the present disclosure are given in weight percent.

[0101] The term "cannabinoid compounds" refers to any one of a class of naturally occurring compounds found in parts of the cannabis plant, Cannabis sativa, Cannabis indica, and Cannabis ruderalis. Cannabinoid compounds are particularly concentrated in the female flower heads. Cannabinoid compounds that occur naturally in the cannabis plant include cannabidiol (CBD) and tetrahydrocannabinol (THC). In this disclosure, the term "cannabinoid compounds" is used to describe both naturally occurring and synthetically produced cannabinoid compounds.

[0102] The flavoring material, such as the gel composition, may comprise a cannabinoid compound selected from the group consisting of cannabidiol (CBD), tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiol acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), cannabicyclol (CBL), cannabivarin (CBV), tetrahydrocannabivarin (THCV), cannabidivarin (CBDV), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabigerol monomethyl ether (CBGM), cannabiersoin (CBE), cannabicitran (CBT), and combinations thereof.

[0103] The flavoring material may include hydroxypropyl methylcellulose. The flavoring material may have a hydroxypropyl methylcellulose content of greater than about 0.5 weight percent. Advantageously, the inventors have discovered that hydroxypropyl methylcellulose can be an effective binder for flavoring materials.

[0104] The flavoring material may have a hydroxypropyl methylcellulose content of greater than about 1 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of greater than about 5 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of greater than about 10 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of greater than about 15 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of greater than about 20 weight percent.

[0105] The flavoring material may have a hydroxypropyl methylcellulose content of less than about 50 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of less than about 45 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of less than about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of less than about 35 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of less than about 30 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of less than about 25 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of less than about 20 weight percent.

[0106] The flavoring material may have a hydroxypropyl methylcellulose content of about 0.5 weight percent to about 50 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 0.5 weight percent to about 45 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 0.5 weight percent to about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 0.5 weight percent to about 35 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 0.5 weight percent to about 30 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 0.5 weight percent to about 25 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 0.5 weight percent to about 20 weight percent.

[0107] The flavoring material may have a hydroxypropyl methylcellulose content of about 0.5 weight percent to about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 1 weight percent to about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 5 weight percent to about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 10 weight percent to about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 15 weight percent to about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 20 weight percent to about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 25 weight percent to about 40 weight percent.

[0108] The flavoring material may have a hydroxypropyl methylcellulose content of about 0.5 weight percent to about 45 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 1 weight percent to about 45 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 1 weight percent to about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 5 weight percent to about 40 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 5 weight percent to about 35 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 10 weight percent to about 35 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 10 weight percent to about 30 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 15 weight percent to about 30 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 15 weight percent to about 25 weight percent. The flavoring material may have a hydroxypropyl methylcellulose content of about 20 percent to about 25 percent by weight.

[0109] The flavoring material may have a cellulosic fortifier content of greater than about 0.5 weight percent. The flavoring material may have a cellulosic fortifier content of greater than about 1 weight percent. The flavoring material may have a cellulosic fortifier content of greater than about 5 weight percent. The flavoring material may have a cellulosic fortifier content of greater than about 10 weight percent. The flavoring material may have a cellulosic fortifier content of greater than about 15 weight percent. The flavoring material may have a cellulosic fortifier content of greater than about 20 weight percent.

[0110] The flavoring material may have a cellulosic fortifier content of less than about 50 weight percent. The flavoring material may have a cellulosic fortifier content of less than about 45 weight percent. The flavoring material may have a cellulosic fortifier content of less than about 40 weight percent. The flavoring material may have a cellulosic fortifier content of less than about 35 weight percent. The flavoring material may have a cellulosic fortifier content of less than about 30 weight percent. The flavoring material may have a cellulosic fortifier content of less than about 25 weight percent. The flavoring material may have a cellulosic fortifier content of less than about 20 weight percent. The flavoring material may have a cellulosic fortifier content of less than about 15 weight percent.

[0111] The flavoring material may have a cellulosic fortifier content of about 0.5 weight percent to about 50 weight percent. The flavoring material may have a cellulosic fortifier content of about 0.5 weight percent to about 45 weight percent. The flavoring material may have a cellulosic fortifier content of about 0.5 weight percent to about 40 weight percent. The flavoring material may have a cellulosic fortifier content of about 0.5 weight percent to about 35 weight percent. The flavoring material may have a cellulosic fortifier content of about 0.5 weight percent to about 30 weight percent. The flavoring material may have a cellulosic fortifier content of about 0.5 weight percent to about 25 weight percent. The flavoring material may have a cellulosic fortifier content of about 0.5 weight percent to about 20 weight percent. The flavoring material may have a cellulosic fortifier content of about 0.5 weight percent to about 15 weight percent. The flavoring material may have a cellulosic fortifier content of about 0.5 weight percent to about 10 weight percent. The flavoring material may have a cellulosic fortifier content of from about 0.5 percent to about 5 percent by weight.

[0112] The flavoring material may have a cellulosic fortifier content of about 1 weight percent to about 40 weight percent. The flavoring material may have a cellulosic fortifier content of about 5 weight percent to about 40 weight percent. The flavoring material may have a cellulosic fortifier content of about 10 weight percent to about 40 weight percent. The flavoring material may have a cellulosic fortifier content of about 15 weight percent to about 40 weight percent. The flavoring material may have a cellulosic fortifier content of about 20 weight percent to about 40 weight percent. The flavoring material may have a cellulosic fortifier content of about 25 weight percent to about 40 weight percent. The flavoring material may have a cellulosic fortifier content of about 30 weight percent to about 40 weight percent. The flavoring material may have a cellulosic fortifier content of about 35 weight percent to about 40 weight percent.

[0113] The flavoring material may have a cellulosic fortifier content of about 1 weight percent to about 35 weight percent. The flavoring material may have a cellulosic fortifier content of about 5 weight percent to about 35 weight percent. The flavoring material may have a cellulosic fortifier content of about 5 weight percent to about 30 weight percent. The flavoring material may have a cellulosic fortifier content of about 10 weight percent to about 30 weight percent. The flavoring material may have a cellulosic fortifier content of about 10 weight percent to about 25 weight percent. The flavoring material may have a cellulosic fortifier content of about 15 weight percent to about 25 weight percent. The flavoring material may have a cellulosic fortifier content of about 15 weight percent to about 20 weight percent.

[0114] The one or more cellulosic fortifiers may comprise cellulose fibers. Advantageously, the inventors have discovered that cellulose fibers can be a cellulosic fortifier that is particularly effective at increasing the tensile strength of a flavoring material.

[0115] The flavoring material may have a cellulose fiber content of greater than about 0.5 weight percent. The flavoring material may have a cellulose fiber content of greater than about 1 weight percent. The flavoring material may have a cellulose fiber content of greater than about 5 weight percent. The flavoring material may have a cellulose fiber content of greater than about 10 weight percent. The flavoring material may have a cellulose fiber content of greater than about 15 weight percent. The flavoring material may have a cellulose fiber content of greater than about 20 weight percent.

[0116] The flavoring material may have a cellulose fiber content of less than about 50 weight percent. The flavoring material may have a cellulose fiber content of less than about 45 weight percent. The flavoring material may have a cellulose fiber content of less than about 40 weight percent. The flavoring material may have a cellulose fiber content of less than about 35 weight percent. The flavoring material may have a cellulose fiber content of less than about 30 weight percent. The flavoring material may have a cellulose fiber content of less than about 25 weight percent. The flavoring material may have a cellulose fiber content of less than about 20 weight percent. The flavoring material may have a cellulose fiber content of less than about 15 weight percent.

[0117] The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 50 weight percent. The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 45 weight percent. The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 40 weight percent. The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 35 weight percent. The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 30 weight percent. The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 25 weight percent. The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 20 weight percent. The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 15 weight percent. The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 10 weight percent. The flavoring material may have a cellulose fiber content of about 0.5 weight percent to about 5 weight percent.

[0118] The flavoring material may have a cellulose fiber content of about 1 weight percent to about 40 weight percent. The flavoring material may have a cellulose fiber content of about 5 weight percent to about 40 weight percent. The flavoring material may have a cellulose fiber content of about 10 weight percent to about 40 weight percent. The flavoring material may have a cellulose fiber content of about 15 weight percent to about 40 weight percent. The flavoring material may have a cellulose fiber content of about 20 weight percent to about 40 weight percent. The flavoring material may have a cellulose fiber content of about 25 weight percent to about 40 weight percent. The flavoring material may have a cellulose fiber content of about 30 weight percent to about 40 weight percent. The flavoring material may have a cellulose fiber content of about 35 weight percent to about 40 weight percent.

[0119] The flavoring material may have a cellulose fiber content of about 1 weight percent to about 35 weight percent. The flavoring material may have a cellulose fiber content of about 5 weight percent to about 35 weight percent. The flavoring material may have a cellulose fiber content of about 5 weight percent to about 30 weight percent. The flavoring material may have a cellulose fiber content of about 10 weight percent to about 30 weight percent. The flavoring material may have a cellulose fiber content of about 10 weight percent to about 25 weight percent. The flavoring material may have a cellulose fiber content of about 15 weight percent to about 25 weight percent. The flavoring material may have a cellulose fiber content of about 15 weight percent to about 20 weight percent.

[0120] The one or more cellulosic fortifiers may include microcrystalline cellulose. Advantageously, the inventors have discovered that microcrystalline cellulose can be a cellulosic fortifier that is particularly effective at increasing the tensile strength of flavor materials.

[0121] The flavoring material may have a microcrystalline cellulose content of greater than about 0.5 weight percent. The flavoring material may have a microcrystalline cellulose content of greater than about 1 weight percent. The flavoring material may have a microcrystalline cellulose content of greater than about 5 weight percent. The flavoring material may have a microcrystalline cellulose content of greater than about 10 weight percent. The flavoring material may have a microcrystalline cellulose content of greater than about 15 weight percent. The flavoring material may have a microcrystalline cellulose content of greater than about 20 weight percent.

[0122] The flavoring material may have a microcrystalline cellulose content of less than about 50 percent by weight. The flavoring material may have a microcrystalline cellulose content of less than about 45 percent by weight. The flavoring material may have a microcrystalline cellulose content of less than about 40 percent by weight. The flavoring material may have a microcrystalline cellulose content of less than about 35 percent by weight. The flavoring material may have a microcrystalline cellulose content of less than about 30 percent by weight. The flavoring material may have a microcrystalline cellulose content of less than about 25 percent by weight. The flavoring material may have a microcrystalline cellulose content of less than about 20 percent by weight. The flavoring material may have a microcrystalline cellulose content of less than about 15 percent by weight.

[0123] The flavoring material may have a microcrystalline cellulose content of about 0.5 weight percent to about 50 weight percent. The flavoring material may have a microcrystalline cellulose content of about 0.5 weight percent to about 45 weight percent. The flavoring material may have a microcrystalline cellulose content of about 0.5 weight percent to about 40 weight percent. The flavoring material may have a microcrystalline cellulose content of about 0.5 weight percent to about 35 weight percent. The flavoring material may have a microcrystalline cellulose content of about 0.5 weight percent to about 30 weight percent. The flavoring material may have a microcrystalline cellulose content of about 0.5 weight percent to about 25 weight percent. The flavoring material may have a microcrystalline cellulose content of about 0.5 weight percent to about 20 weight percent. The flavoring material may have a microcrystalline cellulose content of about 0.5 weight percent to about 15 weight percent. The flavoring material may have a microcrystalline cellulose content of about 0.5 weight percent to about 10 weight percent. The flavoring material may have a microcrystalline cellulose content of from about 0.5 percent to about 5 percent by weight.

[0124] The flavoring material may have a microcrystalline cellulose content of about 1 weight percent to about 40 weight percent. The flavoring material may have a microcrystalline cellulose content of about 5 weight percent to about 40 weight percent. The flavoring material may have a microcrystalline cellulose content of about 10 weight percent to about 40 weight percent. The flavoring material may have a microcrystalline cellulose content of about 15 weight percent to about 40 weight percent. The flavoring material may have a microcrystalline cellulose content of about 20 weight percent to about 40 weight percent. The flavoring material may have a microcrystalline cellulose content of about 25 weight percent to about 40 weight percent. The flavoring material may have a microcrystalline cellulose content of about 30 weight percent to about 40 weight percent. The flavoring material may have a microcrystalline cellulose content of about 35 weight percent to about 40 weight percent.

[0125] The flavoring material may have a microcrystalline cellulose content of about 1 weight percent to about 35 weight percent. The flavoring material may have a microcrystalline cellulose content of about 5 weight percent to about 35 weight percent. The flavoring material may have a microcrystalline cellulose content of about 5 weight percent to about 30 weight percent. The flavoring material may have a microcrystalline cellulose content of about 10 weight percent to about 30 weight percent. The flavoring material may have a microcrystalline cellulose content of about 10 weight percent to about 25 weight percent. The flavoring material may have a microcrystalline cellulose content of about 15 weight percent to about 25 weight percent. The flavoring material may have a microcrystalline cellulose content of about 15 weight percent to about 20 weight percent.

[0126] The one or more cellulosic fortifiers may include cellulose powder. Advantageously, the inventors have discovered that cellulose powder can be a cellulosic fortifier that is particularly effective at increasing the tensile strength of flavor materials.

[0127] The flavoring material may have a cellulose powder content of greater than about 0.5 weight percent. The flavoring material may have a cellulose powder content of greater than about 1 weight percent. The flavoring material may have a cellulose powder content of greater than about 5 weight percent. The flavoring material may have a cellulose powder content of greater than about 10 weight percent. The flavoring material may have a cellulose powder content of greater than about 15 weight percent. The flavoring material may have a cellulose powder content of greater than about 20 weight percent.

[0128] The flavoring material may have a cellulose powder content of less than about 50 weight percent. The flavoring material may have a cellulose powder content of less than about 45 weight percent. The flavoring material may have a cellulose powder content of less than about 40 weight percent. The flavoring material may have a cellulose powder content of less than about 35 weight percent. The flavoring material may have a cellulose powder content of less than about 30 weight percent. The flavoring material may have a cellulose powder content of less than about 25 weight percent. The flavoring material may have a cellulose powder content of less than about 20 weight percent. The flavoring material may have a cellulose powder content of less than about 15 weight percent.

[0129] The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 50 weight percent. The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 45 weight percent. The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 40 weight percent. The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 35 weight percent. The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 30 weight percent. The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 25 weight percent. The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 20 weight percent. The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 15 weight percent. The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 10 weight percent. The flavoring material may have a cellulose powder content of about 0.5 weight percent to about 5 weight percent.

[0130] The flavoring material may have a cellulose powder content of about 1 weight percent to about 40 weight percent. The flavoring material may have a cellulose powder content of about 5 weight percent to about 40 weight percent. The flavoring material may have a cellulose powder content of about 10 weight percent to about 40 weight percent. The flavoring material may have a cellulose powder content of about 15 weight percent to about 40 weight percent. The flavoring material may have a cellulose powder content of about 20 weight percent to about 40 weight percent. The flavoring material may have a cellulose powder content of about 25 weight percent to about 40 weight percent. The flavoring material may have a cellulose powder content of about 30 weight percent to about 40 weight percent. The flavoring material may have a cellulose powder content of about 35 weight percent to about 40 weight percent.

[0131] The flavoring material may have a cellulose powder content of about 1 weight percent to about 35 weight percent. The flavoring material may have a cellulose powder content of about 5 weight percent to about 35 weight percent. The flavoring material may have a cellulose powder content of about 5 weight percent to about 30 weight percent. The flavoring material may have a cellulose powder content of about 10 weight percent to about 30 weight percent. The flavoring material may have a cellulose powder content of about 10 weight percent to about 25 weight percent. The flavoring material may have a cellulose powder content of about 15 weight percent to about 25 weight percent. The flavoring material may have a cellulose powder content of about 15 weight percent to about 20 weight percent.

[0132] The flavoring material may include carboxymethylcellulose. Advantageously, the use of carboxymethylcellulose may help reduce crusting of the flavoring material when used in an aerosol-generating article. In some cases, the use of carboxymethylcellulose eliminates crusting. As used herein, "crusting" is interpreted as the formation of a solid layer on a component of an aerosol-generating article. The inventors have discovered that crusting may occur because a component of the flavoring material may melt and then re-solidify around a component of the aerosol-generating article. When the flavoring material is used in an aerosol-generating device that contains a susceptor, crusting may be a particular problem. If a crust forms on the susceptor, the susceptor with the crust will be less effective in heating the flavoring material, which may result in reduced delivery of nicotine to the user and / or reduced formation of aerosol from the flavoring material.

[0133] The carboxymethylcellulose may include sodium carboxymethylcellulose. Advantageously, the inventors have discovered that sodium carboxymethylcellulose is a carboxymethylcellulose that may be particularly effective in preventing the crusting problem noted above.

[0134] The flavoring material may have a carboxymethylcellulose content of greater than about 0.5 weight percent. The flavoring material may have a carboxymethylcellulose content of greater than about 1 weight percent. The flavoring material may have a carboxymethylcellulose content of greater than about 5 weight percent. The flavoring material may have a carboxymethylcellulose content of greater than about 10 weight percent.

[0135] The flavoring material may have a carboxymethylcellulose content of less than about 20 percent by weight. The flavoring material may have a carboxymethylcellulose content of less than about 15 percent by weight. The flavoring material may have a carboxymethylcellulose content of less than about 10 percent by weight. The flavoring material may have a carboxymethylcellulose content of less than about 8 percent by weight. The flavoring material may have a carboxymethylcellulose content of less than about 5 percent by weight.

[0136] The flavoring material may have a carboxymethylcellulose content of about 0.5 weight percent to about 20 weight percent. The flavoring material may have a carboxymethylcellulose content of about 0.5 weight percent to about 15 weight percent. The flavoring material may have a carboxymethylcellulose content of about 0.5 weight percent to about 10 weight percent. The flavoring material may have a carboxymethylcellulose content of about 0.5 weight percent to about 8 weight percent. The flavoring material may have a carboxymethylcellulose content of about 0.5 weight percent to about 5 weight percent.

[0137] The flavoring material may have a carboxymethylcellulose content of about 1 weight percent to about 20 weight percent. The flavoring material may have a carboxymethylcellulose content of about 5 weight percent to about 20 weight percent. The flavoring material may have a carboxymethylcellulose content of about 8 weight percent to about 20 weight percent. The flavoring material may have a carboxymethylcellulose content of about 10 weight percent to about 20 weight percent. The flavoring material may have a carboxymethylcellulose content of about 15 weight percent to about 20 weight percent.

[0138] The flavoring material may have a carboxymethylcellulose content of about 1 weight percent to about 15 weight percent. The flavoring material may have a carboxymethylcellulose content of about 1 weight percent to about 10 weight percent. The flavoring material may have a carboxymethylcellulose content of about 5 weight percent to about 10 weight percent. The flavoring material may have a carboxymethylcellulose content of about 5 weight percent to about 8 weight percent.

[0139] The flavouring material, such as the gel composition, may have a homogenous distribution.Similarly, the flavouring material, such as the gel composition, may be distributed in a variable manner within the flavour substrate.

[0140] The flavor substrate may include an outer layer, which may be useful for giving the flavor substrate the required shape to be placed within the aerosol-generating article.

[0141] The outer layer may be made of the same material as the remainder of the flavor substrate, for example a flavor material or a gel composition.

[0142] When the flavor substrate comprises an outer layer, the flavor substrate may be manufactured by first depositing a core comprising the remaining portion of the flavor substrate, and then depositing a layer on the core to form the outer layer. This may allow an efficient method of providing a flavor substrate for manufacturing an aerosol-generating article. The core and the outer layer may advantageously be manufactured by extrusion. The outer layer may be free of flavoring agents. The flavor material, such as a gel composition, may be configured to be in a solid state within a temperature range covering the standard environmental temperature for use of the aerosol-generating article. A suitable range of temperatures may be from -20 degrees Celsius to 70 degrees Celsius.

[0143] When the flavor material, such as a gel composition, is in a solid state, it can be configured to have sufficient resistance to deformation to provide the flavor substrate with mechanical stability for handling during manufacture, transportation, and use of the aerosol-generating article. The resistance to deformation strength of the flavor substrate can be about 0.5 kgf to about 3 kgf, preferably about 1.3 kgf to about 2.7 kgf, and more preferably about 1.9 kgf to about 2.5 kgf.

[0144] The resistance of a flavoring material, such as a gel composition, to deformation strength can be adjusted as needed by adjusting the composition of the flavoring material. For example, adjusting the amount of low methoxyl (LM) pectin in the flavoring material can affect the resistance of the flavoring material to deformation strength. The amount of low methoxyl (LM) pectin can be about 0.5 percent to about 5 percent, preferably about 1 percent to about 3 percent.

[0145] Advantageously, the gel composition may be solid at room temperature. "Solid" in this context means that the gel has a stable size and shape and does not flow. Room temperature in this context means 25 degrees Celsius. Gels may be defined as substantially diluted crosslinked systems that do not exhibit flowability at steady state. On a weight basis, gels may be almost liquid, yet they behave like solids due to a three-dimensional crosslinked network within the liquid. Crosslinks within the fluid give the gel its structure (hardness). In this way, gels may be a dispersion of liquid molecules within a solid, with liquid particles dispersed in a solid medium.

[0146] The gel composition may have a viscosity of about 1,000,000 to about 1 Pascal per second, preferably 100,000 to 10 Pascal per second, more preferably 10,000 to 1,000 Pascal per second, or 1,000 to 100 Pascal per second, or 500 to 200 Pascal per second, to provide a desired viscosity. The viscosity of the gel composition is 1 s at 25° C. -1The viscosity of the sample can be measured using an Anton Paar MCR 302 rheometer with a parallel plate PP25 equipped with a P-PTD200+H-PTD200 measuring cell at a shear rate of 100 rpm.

[0147] The mass of the gel composition may not change by more than about 20%, or may not change by more than about 15%, or may not change by more than about 10% when exposed to various environmental storage conditions. The composition may have an exterior shape with an exposed surface area that does not change by more than about 10%, or does not change by more than about 5%, or does not change by more than about 1% when exposed to various environmental conditions.

[0148] The gel composition can have a mass that does not change by more than about 20%, or does not change by more than about 15%, or does not change by more than about 10% when exposed to a relative humidity in the range of about 10% to about 60% at 24 degrees Celsius and one atmosphere of pressure or typical storage conditions.

[0149] The gel composition may have an outer shape with an exposed surface area that does not change by more than about 10%, or does not change by more than about 5%, or does not change by more than about 1%, when exposed to a relative humidity in the range of about 10% to about 60% at 24 degrees Celsius and one atmosphere of pressure.

[0150] The gel composition has an exposed surface area value (m 2 ) and mass values ​​(kg), with mass values ​​to exposed surface area ranging from about 0.05:1 to about 1:1, or from about 0.1:1 to about 1:1, or from about 0.5:1 to about 1:0.1, or from about 0.5:1 to about 1:0.5.

[0151] Advantageously, the gel composition may provide a predictable composition morphology upon storage or upon transport from manufacture to consumer. The gel composition may substantially maintain its shape. The gel composition may not substantially release the liquid phase upon storage or transport from manufacture to consumer. The aerosol-generating article may include a filter disposed longitudinally downstream of the tubular element.

[0152] The gel composition of any permeability control element, such as a flavor substrate or spanning element, may include at least glycerin. The gel composition of any permeability control element, such as a flavor substrate or spanning element, may include at least HPMC. The gel composition of any permeability control element, such as a flavor substrate or spanning element, may include at least agar. The gel composition of any permeability control element, such as a flavor substrate or spanning element, may include at least lactic acid.

[0153] The gel composition of any permeability control element, such as a flavor substrate or spanning element, may include at least glycerin and HPMC.

[0154] The gel composition of any permeability control element, such as a flavor substrate or spanning element, may include at least glycerin, HPMC and agar.

[0155] The gel composition of any permeability control element, such as a flavor substrate or spanning element, may include at least glycerin, HPMC, agar, and lactic acid.

[0156] The gel composition may have a glycerin content of about 52 weight percent. The gel composition may have a hydroxypolymethylcellulose content of about 21.5 weight percent. The gel composition may have a nicotine content of about 1.5 weight percent. The gel composition may have an agar content of about 7.6 weight percent. The gel composition may have a fiber content of about 9 weight percent. The fiber may be cellulose fibers of about 8 to about 15 micrometers in length. The gel composition may have a low methoxyl pectin (E440i) content of about 4 weight percent. The gel composition may have a lactic acid content of about 2.3 weight percent. The gel composition may have a Ca-lactate content of about 2.1 weight percent.

[0157] The gel composition may have a glycerin content of about 53 weight percent. The gel composition may have a hydroxypolymethylcellulose content of about 21 weight percent. The gel composition may have a nicotine content of about 1.1 weight percent. The gel composition may have an agar content of about 8 weight percent. The gel composition may have a fiber content of about 6.8 weight percent. The fiber may be cellulose fibers of about 8 to about 15 micrometers in length. The gel composition may have a low methoxyl pectin (E440i) content of about 5 weight percent. The gel composition may have a lactic acid content of about 2.1 weight percent. The gel composition may have a Ca-lactate content of about 1 weight percent. The gel composition may have a menthol extract (FDA 21CFR182.20) with a menthol (C10H20O) content of about 2 weight percent and a minimum of 55 percent.

[0158] The gel composition may have a glycerin content of about 61 weight percent. The gel composition may have a hydroxypolymethylcellulose content of about 21 weight percent. The gel composition may have a nicotine content of about 1.8 weight percent. The gel composition may have an agar content of about 3 weight percent. The gel composition may have a fiber content of about 7.2 weight percent. The fiber may be cellulose fibers having a length of about 8 to about 15 micrometers. The gel composition may have a low methoxyl pectin (E440i) content of about 3 weight percent. The gel composition may have a lactic acid content of about 3 weight percent.

[0159] The gel composition may have a glycerin content of about 60 weight percent. The gel composition may have a hydroxypolymethylcellulose content of about 22 weight percent. The gel composition may have a nicotine content of about 1.8 weight percent. The gel composition may have an agar content of about 2.4 weight percent. The gel composition may have a fiber content of about 5.3 weight percent. The fiber may be cellulose fibers of about 8 to about 15 micrometers in length. The gel composition may have a low methoxyl pectin (E440i) content of about 4 weight percent. The gel composition may have a lactic acid content of about 2.8 weight percent. The gel composition may have a Ca-lactate composition of about 1 weight percent. The gel composition may have a vanilla extract (FDA 21CFR169.175) and have a vanillin (C8H8O3) content of at least 20 percent of about 1.7 weight percent.

[0160] The term "filter" is used to denote a section of an aerosol-generating article that is configured to at least partially remove gas phase or particulate phase components, or both gas phase and particulate phase components, from the mainstream aerosol drawn through the filter.

[0161] The filter may be positioned longitudinally immediately downstream of the tubular element.

[0162] The filter may be located immediately downstream of the tubular element, i.e., without intermediate components such as aerosol cooling elements, since the tubular element may be useful and sufficient to provide customization of the aerosol formed according to user preferences. Thus, the aerosol-generating article may achieve reduced gas and particulate phase components while requiring fewer production steps and allowing for a more consistent experience.

[0163] However, the aerosol-generating article may include an aerosol cooling element downstream of the tubular element. Preferably, the aerosol cooling element may be located between the tubular element and the filter.

[0164] The aerosol-generating article may include a mouthpiece located at the upstream end of the aerosol-generating article. Providing a mouthpiece may be desirable to facilitate inhalation of the aerosol by a user.

[0165] The aerosol-generating article may include a wrapper surrounding at least a portion of the aerosol-generating article. Advantageously, such a wrapper may prevent a user from touching the aerosol-forming substrate, which helps to maintain a high level of hygiene. The wrapper may be made of any suitable material. In particular, the wrapper may be formed of a porous material. The wrapper may be made of a material that allows volatile compounds to be released from the material when the wrapper is placed around the downstream section of the aerosol-generating article.

[0166] Advantageously, the wrapper may hold together several components of the aerosol-generating article. For example, the wrapper may hold together the aerosol-forming substrate and the tubular element. If the aerosol-generating article includes a filter, the wrapper may hold together the filter and the tubular element.

[0167] Advantageously, the provision of one or more wrappers may improve the structural integrity of the aerosol-generating article.

[0168] The components of the aerosol-generating article may be secured together by any suitable means. For example, the aerosol-generating article may comprise a connecting mechanism. The connecting mechanism may contribute to holding the components of the aerosol-generating article together.

[0169] A wrapper may be provided surrounding at least a portion of the aerosol-generating article, and where the aerosol-generating article includes an attachment mechanism, the wrapper may be configured to apply pressure to the attachment mechanism.

[0170] The aerosol-forming substrate may have any suitable cross-sectional shape. For example, the substrate may have a circular, elliptical, stadium-shaped, rectangular or triangular cross-sectional shape. Preferably, the substrate has a circular cross-sectional shape.

[0171] The solid aerosol-forming substrate may include a tobacco plug. The tobacco plug may include, for example, one or more of powder, granules, pellets, shreds, strands, strips, or sheets, including one or more of herb leaves, tobacco leaves, tobacco stems, expanded tobacco, and homogenized tobacco. The term "homogenized tobacco material" as used herein means a material formed by agglomerating particulate tobacco. Providing homogenized tobacco material may improve aerosol generation and the nicotine content and flavor profile of the aerosol generated during heating of the aerosol-generating article. Specifically, the process of making homogenized tobacco involves grinding tobacco leaves, which allows for more efficient release of nicotine and flavor upon heating. When the tobacco plug includes homogenized tobacco material, the homogenized tobacco material may be in the form of a sheet. As used herein, the term "sheet" means a layered element having a width and length substantially greater than its thickness.

[0172] The solid aerosol-forming substrate may comprise homogenized tobacco material. The solid aerosol-forming material may comprise pieces, strands, or strips of homogenized tobacco material. The solid aerosol-forming substrate may comprise a sheet of homogenized tobacco material.

[0173] The aerosol-forming substrate may have a substantially homogeneous composition.The aerosol-forming substrate may have a substantially homogeneous composition at least in the longitudinal direction.

[0174] The homogenized tobacco material sheet may be formed by agglomerating particulate tobacco obtained by grinding or otherwise comminuted one or both of tobacco lamina and tobacco stems. The homogenized tobacco material sheet may also include one or more of tobacco dust, tobacco fines, and other particulate tobacco by-products formed, for example, during tobacco processing, handling, and transportation. The homogenized tobacco material sheet is preferably formed by a casting process of the type that generally involves casting a slurry including particulate tobacco and one or more binders onto a conveyor belt or other support surface, drying the cast slurry to form a sheet of homogenized tobacco material, and removing the sheet of homogenized tobacco material from the support surface.

[0175] The solid aerosol-forming substrate may comprise an assembly of sheets of homogenized tobacco material. As used herein, the term "assembled" is used to describe a sheet that has been rolled, folded, or otherwise compressed or contracted substantially transverse to the longitudinal axis of the aerosol-generating article.

[0176] The aerosol-forming substrate comprises an assembly of textured sheets of homogenized tobacco material. As used herein, the term "textured sheets" refers to sheets that have been crimped, embossed, debossed, perforated, or otherwise deformed. The use of textured sheets of homogenized tobacco material may advantageously facilitate assembling the sheets of homogenized tobacco material to form the aerosol-forming substrate. The aerosol-forming substrate may comprise an assembly of textured sheets of homogenized tobacco material that include a plurality of spaced indentations, protrusions, perforations, or combinations thereof.

[0177] The aerosol-forming substrate preferably comprises an assembly of a crimped sheet of homogenized tobacco material. As used herein, the term "crimped sheet" refers to a sheet having a plurality of substantially parallel ridges or corrugations. The substantially parallel ridges or corrugations preferably extend along or parallel to the longitudinal axis of the aerosol-generating article. This advantageously facilitates collection of the crimped sheet of homogenized tobacco material for forming the aerosol-generating article. However, it is recognized that a crimped sheet of homogenized tobacco material for inclusion in an aerosol-generating article may have a plurality of substantially parallel ridges or corrugations that are disposed at an acute or obtuse angle to the longitudinal axis of the aerosol-generating article.

[0178] The aerosol-forming substrate may include tobacco-containing and non-tobacco-containing materials.

[0179] The aerosol-forming substrate may include an aerosol former. The aerosol-forming substrate may include a single aerosol former or a combination of two or more aerosol formers. As used herein, the term "aerosol former" is used to describe any suitable known compound or mixture of compounds that facilitates the formation of an aerosol when used and is substantially resistant to thermal decomposition at the operating temperature of the aerosol-generating article. Suitable aerosol formers include, but are not limited to, polyhydric alcohols (such as propylene glycol, triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate and dimethyl tetradecanedioate). Preferred aerosol formers are polyhydric alcohols (such as propylene glycol, triethylene glycol, 1,3-butanediol, and most preferably glycerin) or mixtures thereof. The aerosol-forming substrate may have an aerosol former content of greater than 5 percent on a dry weight basis. The aerosol-forming substrate may have an aerosol former content of about 5 percent to about 30 percent on a dry weight basis.The aerosol-forming substrate may have an aerosol former content of about 20 percent on a dry weight basis.

[0180] The aerosol-forming substrate preferably comprises homogenized tobacco material, an aerosol former, and water.

[0181] The homogenized tobacco material may be provided in a sheet that is folded, crimped, or cut into strips. The sheet may be cut into strips having a width of about 0.2 millimeters to about 2 millimeters, more preferably about 0.4 millimeters to about 1.2 millimeters. The width of the strips may be about 0.9 millimeters.

[0182] The aerosol-forming substrate may include an internal cavity. In other words, the aerosol-forming substrate may be a tubular substrate. The aerosol-forming substrate may include an internal substrate surface having an internal substrate diameter, the internal substrate surface defining an internal cavity extending longitudinally within the aerosol-forming substrate. Providing an internal cavity within the aerosol-forming substrate may allow a heating element to be inserted within the aerosol-forming substrate within the cavity without penetrating the substrate and without modifying the substrate structure. Providing an internal cavity may also be beneficial to further reduce the thickness of the aerosol-forming substrate and enhance the heat transfer advantages discussed above.

[0183] Where the aerosol-forming substrate includes an inner substrate surface that bounds an internal cavity, the inner substrate surface may have the same transverse cross-sectional shape as the outer substrate surface, in particular the inner substrate surface may have a substantially circular, elliptical or stadium-shaped transverse cross-section.

[0184] The aerosol-generating article may comprise a layer of thermally conductive material. The layer of thermally conductive material may cover at least a portion of the aerosol-forming substrate that would otherwise be exposed. The layer of thermally conductive material may be disposed on at least the substrate outer surface. The layer of thermally conductive material may be disposed on at least the substrate inner surface. The layer of thermally conductive material may be disposed on at least the substrate inner surface and on the substrate outer surface. By providing a layer of thermally conductive material on an otherwise exposed substrate surface, heat from a heating element received by or engaged with the substrate may be distributed over a larger area of ​​the aerosol-forming substrate, improving the efficiency of heat transfer between the heating element and the aerosol-forming substrate. The layer of thermally conductive material may also create a physical separation between the heating element received in the internal cavity and the aerosol-forming substrate, which may reduce the risk of overheating the aerosol-forming substrate in an area of ​​the substrate near the heating element. The layer of thermally conductive material may also increase the robustness of the tubular aerosol-forming substrate, which may be reduced by the reduction in the thickness of the substrate due to the provision of an internal cavity.

[0185] As used herein, the term "thermally conductive" refers to a material having a thermal conductivity of at least 10 W / m·K, preferably at least 40 W / m·K, more preferably at least 100 W / m·K at 23 degrees Celsius and 50% relative humidity. Preferably, the layer of thermally conductive material may comprise a material having a thermal conductivity of at least 40 W / m·K, preferably at least 100 W / m·K, more preferably at least 150 W / m·K, even more preferably at least 200 W / m·K at 23 degrees Celsius and 50% relative humidity.

[0186] Examples of suitable conductive materials include, but are not limited to, aluminum, copper, zinc, nickel, silver, and combinations thereof.

[0187] The aerosol-forming substrate may comprise a rod comprising a plurality of elongated tubular elements. The elongated tubular elements may comprise tobacco material. The plurality of elongated tubular elements comprised in the aerosol-forming substrate should not be confused with tubular elements arranged downstream of the aerosol-forming substrate.

[0188] By adjusting the number, equivalent diameter and thickness of the elongated tubular elements of the rod, it may be advantageously possible to adjust the density and porosity of the rod. In general, an aerosol-forming substrate comprising a plurality of elongated tubular elements of homogenized tobacco may advantageously exhibit a more uniform density than an aerosol-forming substrate comprising pieces of tobacco material. The geometric shape of the elongated tubular elements may be such that a particularly stable channel is provided for the airflow along the rod. This may advantageously allow for consistent fine-tuning of the RTD, so that aerosol-forming substrates with a given RTD can be produced in a consistent manner and with great precision.

[0189] The weight of an aerosol-forming substrate comprising elongated tubular elements of homogenized tobacco may be determined by the number, size, density and spacing of the tubular elements, which may reduce weight discrepancies between aerosol-forming substrates of the same dimensions, resulting in a lower rejection rate of aerosol-forming substrates whose weight is outside a selected tolerance range, compared to aerosol-forming substrates comprising shreds of tobacco material.

[0190] Varying the thickness of the elongated tubular elements in the rod may also be advantageously used to adjust the homogenized tobacco content in the rod. For example, in elongated tubular elements formed from wrapped strips of homogenized tobacco web, adjusting the thickness of the elongated tubular elements may be achieved by varying the number of times the strip is wrapped around its longitudinal axis, or by varying the thickness of the homogenized tobacco web itself. This may allow for greater design flexibility compared to aerosol-generating articles that include pieces of tobacco material.

[0191] The size, geometry and arrangement of the elongated tubular elements in the rod can be easily adapted to facilitate insertion of a heating element into the rod of the aerosol-generating article. Since the tubular elements lie substantially straight within the rod and extend longitudinally, the insertion of a longitudinally extending internal heating element (such as a heater blade) can be facilitated. A regular arrangement of the elongated tubular elements in the rod can also advantageously favor the optimization of heat transfer from the heating element through the rod.

[0192] Insertion of the heater of the aerosol-generating device into (and removal of the heater from) an aerosol-forming substrate containing pieces of tobacco material may tend to cause pieces of tobacco material to flake off from the aerosol-forming substrate. This may require more frequent cleaning of the heater element and other parts of the aerosol-generating device to remove the flakes. In contrast, insertion of the heater of the aerosol-generating device into (and removal of) an aerosol-forming substrate comprising a plurality of elongated tubular elements of homogenized tobacco material may advantageously significantly reduce the tendency for material to flake off.

[0193] A rod comprising a plurality of elongated tubular elements can be made in a continuous process that can be carried out quickly and efficiently, and that can be conveniently integrated into existing production lines for the manufacture of aerosol-generating articles.

[0194] The rod of aerosol-forming substrate preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

[0195] The rod of the aerosol-forming substrate may have an outer diameter of at least 5 millimeters. The rod of the aerosol-forming substrate may have an outer diameter of about 5 millimeters to about 12 millimeters, for example about 5 millimeters to about 10 millimeters, or about 6 millimeters to about 8 millimeters. Preferably, the rod of the aerosol-forming substrate may have an outer diameter of 7.2 millimeters ±10 percent.

[0196] The rod of the aerosol-forming substrate may have a length of about 5 mm to about 100 mm. Preferably, the rod of the aerosol-generating substrate has a length of at least about 5 mm, more preferably at least about 7 mm. The rod of the aerosol-generating substrate preferably has a length of less than about 80 mm, more preferably less than about 65 mm, even more preferably less than about 50 mm. Preferably, the rod of the aerosol-generating substrate may have a length of less than about 35 mm, more preferably less than 25 mm, even more preferably less than about 20 mm. The rod of the aerosol-forming substrate may have a length of about 10 mm, and the rod of the aerosol-forming substrate may have a length of about 12 mm.

[0197] The rod of the aerosol-forming substrate may have a substantially uniform cross-section along the length of the rod. It may be preferred that the rod of the aerosol-forming substrate has a substantially circular cross-section.

[0198] The rod comprising the elongate tubular elements may be surrounded by a wrapper. The elongate tubular elements may be assembled such that the elongate tubular elements extend longitudinally.

[0199] The plurality of elongated tubular elements of the rod of the aerosol-generating article according to the invention may be formed of a homogenous tobacco material, which may include particulate tobacco obtained by grinding. The plurality of elongated tubular elements may all have substantially the same composition as each other. Similarly, the plurality of elongated tubular elements may include tubular elements of at least two different compositions.

[0200] At least one elongated tubular element in the rod may comprise a rolled strip cut from a sheet or web of homogenized tobacco material.

[0201] The sheet or web of homogenized tobacco material may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at least about 60 weight percent on a dry weight basis, more preferably or at least about 70 weight percent on a dry weight basis, and most preferably at least about 90 weight percent on a dry weight basis.

[0202] A sheet or web of homogenized tobacco material for use in an aerosol-forming substrate may include one or more intrinsic binders (i.e., tobacco intrinsic binders), one or more extrinsic binders (i.e., tobacco extrinsic binders), or combinations thereof, to aid in agglomerating the particulate tobacco. A sheet of homogenized tobacco material for use in an aerosol-forming substrate may include other additives, including, but not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and non-aqueous solvents, and combinations thereof.

[0203] Suitable extrinsic binders for inclusion in sheets or webs of homogenized tobacco material for use in aerosol-forming substrates are well known in the art and include, but are not limited to, gums (e.g., guar gum, xanthan gum, gum arabic, locust bean gum, etc.), cellulosic binders (e.g., hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, and ethyl cellulose, etc.), polysaccharides (e.g., starch, organic acids (e.g., alginic acid), conjugate base salts of organic acids (e.g., sodium alginate), agar, pectin, etc.), and combinations thereof.

[0204] Suitable non-tobacco fibers for inclusion in a sheet or web of homogenized tobacco material for use in an aerosol-forming substrate are known in the art and include, but are not limited to, cellulose fibers, softwood fibers, hardwood fibers, jute fibers, and combinations thereof. Prior to inclusion in a sheet of homogenized tobacco material for use in an aerosol-forming substrate, the non-tobacco fibers may be treated by any suitable process known in the art, including, but not limited to, mechanical pulping, refining, chemical pulping, bleaching, sulfate pulping, and combinations thereof.

[0205] The sheet or web of homogenized tobacco material may include an aerosol former.

[0206] The homogenized tobacco sheets or webs for use in the aerosol-generating articles of the present invention may be made by methods well known in the art, such as the methods disclosed in WO-A-2012 / 164009 A2. The sheets of homogenized tobacco material for use in the aerosol-generating articles may be formed from a slurry including particulate tobacco, guar gum, cellulose fibers, and glycerin by a casting process.

[0207] Alternatively, the elongated tubular elements of homogenized tobacco material for use in the aerosol-forming substrate according to the invention may be formed by extrusion. By way of example, a slurry containing particulate tobacco obtained by grinding or otherwise comminuted tobacco lamina may be forced through a die of the desired cross-section. Furthermore, additive manufacturing may also be used to produce the tubular elements of homogenized tobacco material.

[0208] The elongate tubular elements may have an equivalent diameter of about 0.03 millimeters to about 3 millimeters. Preferably, the elongate tubular elements may have an equivalent diameter of at least about 0.1 millimeters. More preferably, the elongate tubular elements may have an equivalent diameter of at least about 0.3 millimeters.

[0209] Similarly, the elongate tubular elements may preferably have an equivalent diameter of less than about 2 millimeters. More preferably, the elongate tubular elements may have an equivalent diameter of less than about 1 millimeter.

[0210] The elongate tubular element may have an equivalent diameter of about 0.7 millimeters to about 2.7 millimeters, and the elongate tubular element may have an equivalent diameter of about 0.3 millimeters to about 1.1 millimeters.

[0211] When the elongated tubular elements are formed by rolling strips of homogenized tobacco material, the strips may have a width of at least about 1 millimeter. Preferably, the strips of homogenized tobacco material may have a width of at least about 2 millimeters. More preferably, the strips of homogenized material may have a width of at least about 3 millimeters.

[0212] The homogenized tobacco material strips may have a width of from about 1 millimeter to about 3.5 millimeters, and the homogenized tobacco material strips may have a width of from about 2.4 millimeters to about 8.2 millimeters.

[0213] The homogenized tobacco material strips may be cut from a sheet or web having a thickness of at least about 40 microns, more preferably at least about 60 microns, more preferably at least about 80 microns, and most preferably at least about 100 microns. Similarly, the homogenized tobacco material strips may be cut from a sheet or web having a thickness of about 5000 microns or less, more preferably about 2000 microns or less, more preferably about 1000 microns or less, and most preferably about 500 microns or less. For example, the thickness of the sheet or web may be about 40 microns to about 5000 microns, more preferably about 60 microns to about 2000 microns, more preferably about 80 microns to about 1000 microns, and most preferably about 100 microns to about 500 microns.

[0214] The thickness of the elongate tubular element may be at least about 40 microns, more preferably at least about 80 microns, more preferably at least about 120 microns, and most preferably at least about 160 microns. Similarly, the thickness of the elongate tubular element may be less than about 5000 microns, more preferably less than about 2500 microns, and most preferably less than about 1000 microns.

[0215] The elongated tubular elements may be formed of porous tobacco material so as to allow air to flow through the walls of the tubular elements, i.e. so that air flow along a substantially radial direction in the rod is unimpeded. Where the elongated tubular elements are formed by rolling strips of homogenized tobacco material, the strips themselves may be formed of porous tobacco material.

[0216] The term "porous" as used herein in relation to homogenized tobacco material may indicate that the tobacco material has been produced within a range of inherent porosity such that sufficient pores or gaps are provided within the structure of the sheet or web to allow air flow through the sheet or web in a direction transverse to the surface of the sheet or web. Similarly, the term "porous" may indicate that each sheet or web of tobacco material comprises a plurality of airflow holes to provide the desired porosity. For example, a sheet of tobacco material may be perforated with a pattern of airflow holes before a rolling operation is performed to produce the elongated tubular element of the rod of aerosol-forming substrate. The airflow holes may be perforated randomly or uniformly across the sheet. The pattern of airflow holes may cover substantially the entire surface of the sheet, or may cover one or more specific areas of the sheet, with the remaining areas being devoid of airflow holes.

[0217] The strips of homogenized tobacco material from which the elongated tubular elements may be formed may be textured. For example, the sheet or web from which the strips are cut may comprise a plurality of spaced apart indentations, protrusions, perforations, or combinations thereof. The texture may be provided on one side of each sheet, or on both sides of each sheet.

[0218] The inclusion of one or more elongated tubular elements formed from the crimped strip can help to provide and maintain some spacing between adjacent tubular elements within the rod.

[0219] The additive may be applied to at least a portion of the surface of at least one of the plurality of tubular elements. The additive may be a solid additive, a liquid additive, or a combination of solid and liquid additives. Suitable solid and liquid additives for use in the present invention are well known in the art and include, but are not limited to, flavorants (e.g., menthol, etc.), adsorbents (e.g., activated carbon, etc.), fillers (e.g., calcium carbonate, etc.), and botanical additives.

[0220] To form a substantially elongated tubular element, the strip of homogenized tobacco material may be wrapped at least about 345 degrees about the longitudinal axis. Preferably, the strip of homogenized tobacco material may be wrapped at least about 360 degrees about the longitudinal axis. More preferably, the strip of homogenized tobacco material may be wrapped at least about 540 degrees about the longitudinal axis. Similarly, the strip of homogenized tobacco material may preferably be wrapped less than about 1800 degrees about the longitudinal axis. More preferably, the strip of homogenized tobacco material may be wrapped less than about 900 degrees about the longitudinal axis. Preferably, the strip of homogenized tobacco material may be wrapped between about 345 degrees and about 540 degrees about the longitudinal axis.

[0221] Each elongate tubular element may have a length substantially equal to the length of the rod of the aerosol-forming substrate. Each elongate tubular element may have a length of about 10 millimeters, and each elongate tubular element may be about 12 millimeters long.

[0222] The rod of the aerosol-forming substrate may comprise less than about 200 elongated tubular elements of the homogenized tobacco material. More preferably, the rod of the aerosol-forming substrate may comprise less than about 150 elongated tubular elements. Even more preferably, the rod of the aerosol-forming substrate may comprise less than about 100 elongated tubular elements.

[0223] Similarly, the rod of the aerosol-forming substrate may comprise at least about 15 elongated tubular elements of homogenized tobacco material. More preferably, the rod of the aerosol-forming substrate may comprise at least about 30 elongated tubular elements. Even more preferably, the rod of the aerosol-forming substrate may comprise at least about 40 elongated tubular elements. The rod of the aerosol-forming substrate may comprise from about 15 to about 100 strands of non-tobacco material.

[0224] In the rod of the aerosol-forming substrate, the elongated tubular elements may be aligned substantially parallel to one another.

[0225] The elongated tubular element of homogenized tobacco material may have a substantially oval cross-section, a substantially elliptical cross-section, or a substantially circular cross-section. As noted above, the elongated tubular element for use in the aerosol-generating article may be effectively formed by wrapping a strip of homogenized tobacco material slightly less than 360 degrees around its longitudinal axis. This results in an element that effectively has a C-shaped cross-section, with the slits extending longitudinally the entire length of the elongated tubular element.

[0226] The plurality of elongated tubular elements forming the rod of the aerosol-forming substrate may be surrounded by a wrapper. The wrapper may be formed of a porous or non-porous sheet material. The wrapper may be formed of any suitable material or combination of materials. The wrapper may be a paper wrapper. The wrapper may optionally be glued to the outer edges of the plurality of elongated tubular elements. For example, the inner surface of the wrapper and at least one of the outer edges of the plurality of elongated tubular elements may be moistened during the production process such that the inner wrapper adheres to the edges of the elongated tubular elements during the wrapping process. Similarly, adhesive may be applied to the inner surface of the wrapper and at least one of the outer edges of the plurality of elongated tubular elements upstream of the wrapping process. The adhesion of the plurality of elongated tubular elements and the wrapper may advantageously help to maintain the position and spacing of the plurality of elongated tubular elements within the rod.

[0227] The wrapper may be at least partially folded over the elongate tubular elements at the upstream and downstream ends of the rod to hold the plurality of elongate tubular elements within the rod. The wrapper may be on the periphery of the plurality of elongate tubular elements at the upstream and downstream ends of the rod such that the remainder of the elongate tubular elements are exposed. The wrapper may be on the entire upstream and downstream ends of the rod.

[0228] Separate rim sections of paper or other material may be attached to the wrapper to cover at least the outer periphery of the upstream and downstream ends of the elongate tubular elements, as described above. When the wrapper is folded over the end of the rod or separate rim sections are provided, an additional outer wrapper may be provided over the wrapper surrounding the multiple elongate tubular elements.

[0229] Rods for use in an aerosol-generating article as described above may be manufactured by the method described below. In a first step of the method, a sheet or web of homogenized tobacco material may be provided. In a second step, elongated strips having a longitudinal axis may be cut from the sheet or web of homogenized tobacco material. The cutting operation may be performed by feeding the sheet or web from a roll or bobbin and moving it continuously along a predetermined direction. Cutting means may be provided at a cutting station to which the web or sheet is fed. For this purpose, a mechanical cutter may be used. A laser may also be used.

[0230] In a third step, the strip may be wound, i.e. wrapped around a longitudinal axis, to form an elongated tubular element. This may be achieved by feeding the strip into a funnel-shaped element along a predetermined direction, such that the strip is coiled and formed into a wound elongated tubular element. Several individual wound elongated tubular elements may be produced in parallel.

[0231] In a fourth step, the plurality of elongated tubular elements obtained at the end of the third step may be assembled in an aligned manner such that the elongated tubular elements extend in the longitudinal direction, which may be achieved by feeding the plurality of elongated tubular elements through another funnel element such that the plurality of elongated tubular elements are grouped in substantially cylindrical clusters.

[0232] In a fifth step, the assembled elongated tubular elements may be surrounded by a wrapper to form a continuous rod, and in a sixth step, the continuous rod may be cut into a plurality of individual rods.

[0233] The method may include the further step of applying at least one aerosol former to the sheet or web of homogenized material prior to the step of cutting the sheet or web to obtain strips.The method may include the further step of applying at least one aerosol former to the elongated tubular elements prior to the step of assembling a plurality of elongated tubular members side-by-side.

[0234] Additionally, the method may include the further step of applying at least one aerosol former to the plurality of elongated tubular elements after the plurality of elongated tubular elements are aligned and assembled.Similarly, the method may include the step of applying at least one aerosol former to the plurality of elongated tubular elements after the step of cutting the continuous rod into individual rods.

[0235] The method may further include the step of drying the homogenized tobacco material after the step of applying at least one aerosol former.

[0236] An aerosol generating system is also provided. The aerosol generating system may comprise any of the aerosol generating articles disclosed above and an aerosol generating device comprising a heater for heating the aerosol generating article. The heater may comprise a substrate heating element configured to heat the aerosol-forming substrate and a downstream heating element disposed downstream of the substrate heating element. The downstream heating element may be configured to heat the flavor substrate. The downstream heating element may be configured to heat at least one permeable control element. The downstream heating element may be configured to heat the spanning element.

[0237] As used herein, the term "aerosol generating system" refers to the combination of an aerosol generating device and an aerosol generating article.

[0238] Since the aerosol generating system of the present disclosure comprises an aerosol-generating article according to the above disclosure, the advantages described above for the aerosol-generating article also apply to the system itself. In particular, the aerosol generating device can be used to generate a substrate aerosol and a flavor aerosol upon heating of the aerosol-forming substrate and the flavor substrate, respectively. Depending on the configuration of the aerosol-generating article, the aerosol generating device can be used to achieve a change in the permeability of the flavor substrate, at least one permeability control element, the spanning element, and any combination thereof.

[0239] The base heating element and the downstream heating element may be any suitable type of heating element. The base heating element may be an internal heating element. The downstream heating element may be an internal heating element. As used herein, the term "internal heating element" refers to a heating element configured to be inserted into the aerosol-forming or flavor substrate. The base heating element and the downstream heating element may be elongated heating elements. The elongated heating element may be blade-shaped. The elongated heating element may be pin-shaped. The elongated heating element may have a tapered shape, or at least a tapered end. The elongated heating element may have a pointed end. The heating element may be cone-shaped. The elongated heating element may have any suitable shape arranged to facilitate insertion of the heating element into the aerosol-forming or flavor substrate. Advantageously, the elongated heating element may provide easier engagement or easier disengagement, or both easier engagement and easier disengagement, of the heating element of the device with the aerosol-generating article.

[0240] The substrate heating element may be an external heating element. The downstream heating element may be an external heating element. As used herein, the term "external heating element" refers to a heating element configured to heat the outer surface of the aerosol-forming substrate or flavor substrate. At least one external heating element may at least partially surround a cavity for receiving the aerosol-forming substrate or flavor substrate.

[0241] The heater may include at least one resistive heating element.

[0242] The substrate heating element may be a resistive heating element, i.e. the heater may include a substrate resistive heating element. The downstream heating element may be a resistive heating element, i.e. the heater may include a downstream resistive heating element.

[0243] The substrate resistive heating element and the downstream resistive heating element may be electrically connected in a parallel arrangement. Advantageously, providing multiple resistive heating elements electrically connected in a parallel arrangement may facilitate delivery of desired power to the heating elements while reducing or minimizing the voltage required to provide the desired power. Advantageously, reducing or minimizing the voltage required to operate at least one heating element may facilitate reducing or minimizing the physical size of the power supply.

[0244] At least one resistive heating element may include an electrically insulating substrate and one or more conductive tracks on the electrically insulating substrate.

[0245] The electrically insulating substrate may be stable at the operating temperature of the at least one heating element. The electrically insulating substrate may be stable at temperatures up to about 400 degrees Celsius, more preferably about 500 degrees Celsius, more preferably about 600 degrees Celsius, more preferably about 700 degrees Celsius, and most preferably about 800 degrees Celsius.

[0246] The operating temperature of the at least one resistive heating element during use may be at least about 200 degrees Celsius. The operating temperature of the at least one resistive heating element during use may be less than about 700 degrees Celsius. The operating temperature of the at least one resistive heating element during use may be less than about 600 degrees Celsius. The operating temperature of the at least one resistive heating element during use may be less than about 500 degrees Celsius. The operating temperature of the at least one resistive heating element during use may be less than about 400 degrees Celsius.

[0247] The electrically insulating substrate may comprise any suitable material. For example, the electrically insulating substrate may comprise one or more of paper, glass, ceramic, anodized metal, coated metal, and polyimide. Ceramics include mica, alumina (Al2O3), or zirconia (ZrO 2) The electrically insulating substrate may have a thermal conductivity of about 40 Watts / meter Kelvin or less, preferably about 20 Watts / meter Kelvin or less, and ideally about 2 Watts / meter Kelvin or less.

[0248] Suitable materials for forming the resistive heating element, and in particular the one or more conductive tracks, include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys, and composites made of ceramic and metallic materials. Such composites may include doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel-, iron-, cobalt-, and stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum-based alloys.

[0249] The resistive heating elements may include one or more stamped sections of an electrically resistive material (such as stainless steel). At least one resistive heating element may include a heating wire or filament (e.g., Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire).

[0250] The heater may include at least one induction heating device.

[0251] The substrate heating element may be an induction heating device, i.e. the heater may include a substrate induction heating device. The downstream heating element may be an induction heating device, i.e. the heater may include a downstream induction heating device.

[0252] The at least one induction heating device may include at least one inductor coil. The at least one induction heating device may include a base inductor coil. The at least one induction heating device may include a downstream inductor coil. The inductor coil is arranged to generate a varying magnetic field upon receiving a varying current from a power source. Such varying current may be from about 5 kilohertz to about 500 kilohertz. The varying current may be a high frequency varying current. As used herein, the term "high frequency varying current" refers to a varying current having a frequency of from about 500 kilohertz to about 30 megahertz. The high frequency varying current may have a frequency of from about 1 megahertz to about 30 megahertz (such as from about 1 megahertz to about 10 megahertz, or from about 5 megahertz to about 8 megahertz). The varying current may be an alternating current that generates an alternating magnetic field.

[0253] The inductor coil may have any suitable form. For example, the inductor coil may be a flat inductor coil. The flat inductor coil may be helically wound in a substantially plane. Preferably, the inductor coil may be a tubular inductor coil. Typically, the tubular inductor coil may be helically wound about a longitudinal axis. The inductor coil may be elongated. Particularly preferably, the inductor coil may be an elongated tubular inductor coil. The inductor coil may have any suitable cross-section. For example, the inductor coil may have a circular, elliptical, square, rectangular, triangular, or other polygonal cross-section.

[0254] The inductor coil may be formed from any suitable material. The inductor coil may be formed from a conductive material. Preferably, the inductor coil may be formed from a metal or metal alloy.

[0255] As used herein, "conductivity" refers to a resistance greater than 1×10 at 20 degrees Celsius -4 Refers to materials that have an electrical resistivity of less than or equal to the ohm-meter (Ω·m).

[0256] The at least one induction heating device may include at least one susceptor. The at least one induction heating device may include a substrate susceptor. The at least one induction heating device may include a downstream susceptor. As used herein, the term "susceptor" refers to an element that includes a material capable of converting magnetic energy into heat. When the susceptor is placed in a varying magnetic field, such as a varying magnetic field generated by an inductor coil, the susceptor is heated. For example, when the substrate susceptor is placed in a varying magnetic field generated by a suspended inductor coil, the substrate susceptor may be heated, and when the downstream susceptor is placed in a varying magnetic field generated by a downstream inductor coil, the downstream susceptor may be heated.

[0257] Heating of the susceptor can be the result of hysteresis losses and / or eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material. Hysteresis losses occur in ferromagnetic or ferrimagnetic susceptor materials due to magnetic domains in the material being switched under the influence of a fluctuating electromagnetic field. Eddy currents can be induced if the susceptor material is conductive. In the case of a conductive ferromagnetic or ferrimagnetic susceptor material, heat can be generated by both eddy currents and hysteresis losses. Thus, the susceptor can be heatable by at least one of hysteresis losses or eddy currents, depending on the electrical and magnetic properties of the susceptor material.

[0258] The susceptor may be arranged such that when the aerosol-generating article is received in the aerosol generating device, the oscillating electromagnetic field generated by the inductor coil induces a current in the susceptor, heating the susceptor. The aerosol generating device is preferably capable of generating an alternating electromagnetic field having a magnetic field strength (H field strength) of 1 to 5 kiloamperes per meter (kA / m), preferably 2 to 3 kA / m, for example about 2.5 kA / m. The aerosol generating device is preferably capable of generating an alternating electromagnetic field having a frequency of 1 to 30 MHz, for example 1 to 10 MHz, for example 5 to 7 MHz.

[0259] The susceptor may comprise any suitable material. The susceptor may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-forming substrate or flavor substrate. A preferred susceptor may be heated to a temperature greater than about 250 degrees Celsius. A preferred susceptor may be formed from an electrically conductive material. Suitable materials for the susceptor include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and composites of metallic materials. A preferred susceptor may comprise metal or carbon. Some preferred susceptors may comprise ferromagnetic materials, such as, for example, ferritic iron, ferromagnetic alloys, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrites. Some preferred susceptors may be comprised of ferromagnetic materials. A preferred susceptor may comprise aluminum. A preferred susceptor may be comprised of aluminum. The susceptor may include at least about 5 percent, at least about 20 percent, at least about 50 percent, or at least about 90 percent of a ferromagnetic or paramagnetic material.

[0260] Preferably, the susceptor may be formed from a material that is substantially impermeable to gas, in other words, the susceptor may be preferably formed from a material that is not gas permeable.

[0261] The susceptor may have any suitable shape. For example, the susceptor may be elongated. The susceptor may have any suitable cross-section. For example, the susceptor may have a circular, oval, square, rectangular, triangular, or other polygonal cross-section. The susceptor may be tubular.

[0262] The susceptor may include a susceptor layer provided on a support. Placing the susceptor in a varying magnetic field induces eddy currents adjacent to the susceptor surface, resulting in an effect called the skin effect. Thus, the susceptor can be formed from a relatively thin layer of susceptor material while ensuring that the susceptor is effectively heated in the presence of the varying magnetic field. Making the susceptor from a support and a relatively thin susceptor layer can facilitate the manufacture of a simple, inexpensive and robust aerosol-generating article.

[0263] The support may be formed from a material that is not susceptible to inductive heating, which may advantageously reduce heating of the surface of the susceptor that is not in contact with the aerosol-forming substrate, where the surface of the support forms the surface of the susceptor that is not in contact with the aerosol-forming substrate.

[0264] The support may comprise an electrically insulating material. As used herein, "electrically insulating" means having a thermal conductivity of at least 1x10 at 20 degrees Celsius. 4 Refers to a material that has an electrical resistivity in ohmmeters (Ωm).

[0265] Forming the support from an insulating material can provide an insulating barrier between the susceptor layer and other components of the induction heating apparatus, such as the inductor coil that surrounds the induction heating element, which can advantageously reduce heat transfer between the susceptor and other components of the induction heating system.

[0266] Insulating materials also have a thermal conductivity of approximately 0.01 square centimeters per second (cm) when measured using the laser flash method. 2 / s) or less. Providing a support with such a thermal diffusivity may result in a support with high thermal inertia, which may reduce heat transfer between the susceptor layer and the support and reduce fluctuations in temperature of the support.

[0267] The susceptor may include a protective outer layer, such as a protective ceramic or glass layer. The protective outer layer may improve the durability of the susceptor and facilitate cleaning of the susceptor. The protective outer layer may substantially surround the susceptor. The susceptor may include a protective coating formed from glass, ceramic, or an inert metal.

[0268] The susceptor may have any suitable dimensions. The susceptor may have a length of about 5 millimeters to about 15 millimeters, for example, about 6 millimeters to about 12 millimeters, or about 8 millimeters to about 10 millimeters. The susceptor may have a width of about 1 millimeter to about 8 millimeters, for example, about 3 millimeters to about 5 millimeters. The susceptor may have a thickness of about 0.01 millimeters to about 2 millimeters. When the susceptor has a constant cross-section, for example a circular cross-section, the susceptor may have a preferred width or diameter of about 1 millimeter to about 5 millimeters.

[0269] The susceptor may be located within the device cavity. The susceptor may extend into the device cavity along a longitudinal axis of the device cavity. The susceptor may be elongated. The elongated susceptor may be blade shaped. The elongated susceptor may be pin shaped. The elongated susceptor may be tapered, or at least have a tapered end. The elongated susceptor may have a pointed end. The elongated element may be cone shaped.

[0270] The substrate susceptor may be an internal heating element configured to be at least partially inserted into the aerosol-forming substrate of the aerosol-generating article when the aerosol-generating article is received within the device cavity. If the aerosol-forming substrate comprises an internal cavity, the substrate susceptor may be configured to be at least partially inserted into the internal cavity of the aerosol-forming substrate when the aerosol-generating article is received within the device cavity.

[0271] The downstream susceptor may be an internal heating element configured to be inserted at least partially into the flavor substrate of the aerosol-generating article when the aerosol-generating article is received within the device cavity.

[0272] The substrate susceptor may be an external heating element configured to at least partially surround a cavity for receiving the aerosol-forming substrate.

[0273] The downstream susceptor may be an external heating element configured to at least partially surround a cavity for receiving the flavor substrate.

[0274] The induction heating device may include at least one internal heating element and at least one external heating element.

[0275] The heater may comprise at least one resistive heating element and at least one inductive heating element. The heater may include a combination of resistive and inductive heating elements.

[0276] The aerosol generating device may include a power source. The power source may be a DC voltage source. The power source may be a battery. For example, the power source may be a nickel metal hydride battery, a nickel cadmium battery, or a lithium-based battery (e.g., a lithium cobalt battery, a lithium iron phosphate battery, or a lithium polymer battery). The power source may be another form of charge storage device, such as a capacitor. The power source may require recharging and may have the capacity to store enough energy to use the aerosol generating device.

[0277] A power source may be electrically connected to the heater to provide power to the heating elements, such as the substrate heating element and the downstream heating element. When the heating elements receive power from the power source, the heating elements may generate heat. The power source may be configured to provide sufficient power to the substrate heating element to heat the aerosol-forming substrate to a temperature at which the volatile compound is released from the aerosol-forming substrate. The power source may be configured to provide sufficient power to the downstream heating element to heat the flavor substrate to a temperature at which the volatile compound is released from the flavor substrate. The power source may be configured to provide sufficient power to the downstream heating element to heat the at least one permeable control element to a temperature at which the at least one permeable control element is fluid permeable, i.e., to heat the at least one permeable control element to its permeability transition temperature.

[0278] The aerosol generating device may comprise a housing. The housing may at least partially define a cavity for receiving the aerosol generating article.

[0279] The aerosol-generating device may comprise at least one device air inlet in fluid communication with the cavity. When the aerosol-generating device comprises a housing, the housing may at least partially define the at least one device air inlet. The housing may define the base device air inlet proximate the distal end of the cavity. It may be desirable for the base device air inlet to allow ambient air to be drawn into the upstream end of the aerosol-forming substrate. The housing may define the downstream device air inlet. The downstream device air inlet may be advantageous to allow ambient air to be drawn into the tubular element air inlet. The downstream device air inlet may be configured to substantially coincide with the tubular element air inlet when the aerosol-generating article is fully introduced into the cavity to receive the aerosol-generating article.

[0280] The aerosol generating device may include a controller. The controller may be configured to control the power supply from the power source to the heating element. The controller may be any suitable controller. The controller may include any suitable electrical circuitry and electrical components. The controller may include a processor and a memory. The controller may include a microprocessor, which may be a programmable microprocessor.

[0281] The aerosol generating device may include a sensor for detecting airflow indicative of a user taking a puff. The airflow sensor may be an electromechanical device. The airflow sensor may be any of a mechanical device, an optical device, an opto-mechanical device, and a microelectromechanical system (MEMS) based sensor. The aerosol generating device may include a manually operable switch for a user to initiate a puff.

[0282] The aerosol generating device may include an indicator for indicating when the at least one heating element is activated. The indicator may include a light that is activated when the at least one heating element is activated.

[0283] The aerosol generating device may include at least one electrical connector. The at least one electrical connector may be configured to charge a power source. The at least one electrical connector may be configured to connect to another electrical device. The at least one electrical connector may include an outer plug or socket with at least one outer electrical contact that allows the aerosol generating device to be connected to another electrical device. For example, the aerosol generating device may include a USB plug or socket that allows the aerosol generating device to be connected to another USB-enabled device. For example, the USB plug or socket may allow the aerosol generating device to be connected to a USB charging device to charge a rechargeable power source within the aerosol generating device. The USB plug or socket may support data transfer to and / or from the aerosol generating device. Similarly, the aerosol generating device may be connected to a computer to transfer data to the device, such as a new heating profile for a new aerosol-generating article.

[0284] When the aerosol generating device comprises a USB plug or socket, the aerosol generating device may further comprise a removable cover for covering the USB plug or socket when not in use When the USB plug or socket is a USB plug, the USB plug may be selectively retractable within the device.

[0285] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment or disclosure described herein.

[0286] Example 1a. 1. An aerosol-generating article having an upstream end and a downstream end, the aerosol-generating article defining a longitudinal direction between the upstream end and the downstream end, the aerosol-generating article comprising: an aerosol-forming substrate; a tubular element arranged downstream of the aerosol-forming substrate and extending along a longitudinal axis, the tubular element comprising an inner tube and an outer tube, the outer tube being arranged around the inner tube, an outer airflow channel being bounded longitudinally by the inner tube and the outer tube, the inner airflow channel being bounded longitudinally by the inner tube, and at least the inner airflow channel being adapted for the substrate aerosol to flow towards a downstream end; An aerosol-generating article comprising at least one permeable control element disposed within the outer airflow channel, preferably the at least one permeable control element being or comprising a flavor substrate disposed downstream of the aerosol-forming substrate. Example 1. 1. An aerosol-generating article having an upstream end and a downstream end, the aerosol-generating article defining a longitudinal direction between the upstream end and the downstream end, the aerosol-generating article comprising: an aerosol-forming substrate; a tubular element arranged downstream of the aerosol-forming substrate and extending along a longitudinal axis, the tubular element comprising an inner tube and an outer tube, the outer tube being arranged around the inner tube, an outer airflow channel being bounded longitudinally by the inner tube and the outer tube, the inner airflow channel being bounded longitudinally by the inner tube, and at least the inner airflow channel being adapted to flow the substrate aerosol towards a downstream end; a flavour substrate disposed downstream of the aerosol-forming substrate; and at least one permeable control element disposed within the outer airflow channel. Example 2. the at least one permeability control element is configured to be fluid permeable when a temperature of the at least one permeability control element is equal to or greater than a permeability transition temperature of the at least one permeability control element, the permeability transition temperature of the at least one permeability control element being a phase transition temperature of the at least one permeability control element; the at least one permeability control element is configured to be substantially fluid impermeable when a temperature of the at least one permeability control element is below a permeability transition temperature of the at least one permeability control element; The aerosol-generating article of Example 1a or Example 1, wherein at least one permeable control element is configured to prevent fluid from flowing along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is lower than the permeability transition temperature of the at least one permeable control element, and to allow fluid to flow along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is equal to or higher than the permeability transition temperature of the at least one permeable control element. Example 3. An aerosol-generating article as described in Example 1 or Example 2, wherein at least one permeable control element is configured to prevent fluid from flowing along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is 20 degrees Celsius, and to allow fluid to flow along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is 85 degrees Celsius. Example 4. An aerosol-generating article according to any one of Examples 1 to 3, wherein at least one permeable control element comprises a gel composition. Example 5. An aerosol-generating article according to any one of Examples 1 to 4, wherein at least one permeability control element comprises a thermoreversible material, such as a thermoreversible gel composition. Example 6. An aerosol-generating article according to any one of Examples 1-E5, wherein the flavor substrate is disposed within the outer airflow channel. Example 7. 7. The aerosol-generating article of Example 6, wherein the flavor substrate is a permeable control element. Example 8. An aerosol-generating article according to any one of Examples 6 to 7, wherein the permeability control element is disposed downstream of the flavor substrate. Example 9. An aerosol-generating article according to any one of Examples 1 to 8, further comprising a spanning element disposed within the outer airflow channel upstream of the flavor substrate. Example 10. The aerosol-generating article of example 9, wherein the spanning element is a permeability control element. Example 11. 8. The aerosol-generating article of Example 7, wherein the flavor substrate extends longitudinally along the entire airflow channel. Example 12. An aerosol-generating article as described in any one of Examples 1 to 11, further comprising an air inlet configured to allow intake of outside air into the outer airflow channel. Example 13. The aerosol-generating article of Example 12 when dependent from Example 9 or Example 10, wherein the air inlet is located downstream of the spanning element. Example 14. The aerosol-generating article of example 12 or example 13, wherein the flavor substrate is positioned downstream of the air inlet. Example 15. An aerosol-generating article according to any one of Examples 1 to 14, wherein the tubular element is positioned longitudinally immediately downstream of the aerosol-forming substrate. Example 16. An aerosol-generating article according to any one of Examples 1 to 15, further comprising a filter disposed downstream of the tubular element. Example 17. 17. The aerosol-generating article of Example 16, wherein the filter is positioned longitudinally immediately downstream of the tubular element. Example 18. An aerosol-generating article as described in any one of Examples 1 to 17, further comprising an aerosol-cooling element longitudinally disposed downstream of the tubular element. Example 19. The aerosol-generating article of Example 18 when dependent from Example 16 or Example 17, wherein the aerosol-cooling element is disposed between the tubular element and the filter. Example 20. The aerosol-generating article of any one of Examples 1 to 19, further comprising a wrapper surrounding at least a portion of the aerosol-generating article. Example 21. An aerosol-generating article according to any one of Examples 1 to 20, further comprising a connection mechanism configured to hold two or more components of the aerosol-generating article together. Example 22. An aerosol-generating article described in any one of Examples 22 to 6, wherein the resistance to withdrawal of the aerosol-generating article when at least one permeable control element is fluid-permeable is at least about 10 mmH2O greater than the resistance to withdrawal of the aerosol-generating article when at least one permeable control element is substantially fluid-impermeable. Example 23. An aerosol-generating article as described in Example 22, wherein the resistance to withdrawal of the aerosol-generating article when at least one permeable control element is fluid-permeable is at least about 20 mmH2O greater than the resistance to withdrawal of the aerosol-generating article when at least one permeable control element is substantially fluid-impermeable. Example 24. An aerosol-generating article as described in Example 23, wherein the resistance to withdrawal of the aerosol-generating article when at least one permeable control element is fluid-permeable is at least about 30 mmH2O greater than the resistance to withdrawal of the aerosol-generating article when at least one permeable control element is substantially fluid-impermeable. Example 25. An aerosol-generating article described in any one of Examples 1 to 24, wherein the resistance to withdrawal of the aerosol-generating article when at least one permeable control element is substantially fluid impermeable is greater than about 20 mmH2O, preferably greater than about 30 mmH2O, more preferably greater than about 40 mmH2O, even more preferably greater than about 50 mmH2O, and most preferably greater than about 60 mmH2O. Example 26. An aerosol-generating article as described in any one of Examples 1 to 25, wherein the resistance to withdrawal of the aerosol-generating article when at least one permeable control element is fluid-permeable is less than about 50 mmH2O, more preferably less than about 40 mmH2O, even more preferably less than about 30 mmH2O, even more preferably less than about 20 mmH2O, and most preferably less than about 10 mmH2O. Example 27. 13. The aerosol-generating article according to any one of Examples 1 to 26, wherein the flavor base comprises a gel composition. Example 28. An aerosol-generating article as described in Example 27, wherein the gel composition is configured to be fluid-permeable when the temperature of the gel composition is equal to or higher than the permeability transition temperature of the gel composition, and wherein the gel composition is configured to be substantially fluid-impermeable when the temperature of the gel composition is lower than the permeability transition temperature of the gel composition, and preferably the permeability transition temperature of the gel composition is the phase transition temperature of the gel composition. Example 29. 29. The aerosol-generating article of Example 28, wherein the gel composition has a permeability transition temperature of 70 degrees Celsius to 80 degrees Celsius. Example 30. An aerosol-generating article described in any one of Examples 27 to 29, wherein the gel composition is configured to be fluid-permeable at 85 degrees Celsius and the gel composition is configured to be substantially fluid-impermeable at 20 degrees Celsius. Example 31. An aerosol-generating article according to any one of Examples 27 to 30, wherein the gel composition is thermoreversible. Example 32. An aerosol-generating article according to any one of Examples 27 to 31, wherein the gel composition preferably contains about 0.1% to about 4%, more preferably about 0.1% to 2%, of nicotine. Example 33. An aerosol-generating article according to any one of Examples 27 to 32, wherein the gel composition comprises a flavoring agent. Example 34. The aerosol-generating article of Example 33, wherein the flavoring agent comprises one or more of coffee derivative flavoring agents including menthol, caffeine, guanidine, taurine, and glucuronolactone. Example 35. An aerosol-generating article according to any one of Examples 27 to 34, wherein the gel composition preferably contains about 50% to about 75%, more preferably about 50% to about 65%, of glycerin. Example 36. An aerosol-generating article according to any one of Examples 27 to 35, wherein the gel composition preferably contains from about 15% to about 35%, more preferably from about 18% to about 32%, even more preferably from about 20% to about 30%, and most preferably from about 21% to about 27% hydroxypolymethylcellulose (HPMC). Example 37. An aerosol-generating article according to any one of Examples 27 to 36, wherein the gel composition preferably contains about 3% to about 10%, more preferably about 4% to about 7%, of agar. Example 38. An aerosol-generating article according to any one of Examples 27 to 37, wherein the gel composition preferably contains from about 0.1% to about 12%, more preferably from about 0.1% to 7%, of fibers. Example 39. An aerosol-generating article according to any one of Examples 27 to 38, wherein the gel composition preferably contains from about 0.1% to about 9%, more preferably from about 0.1% to 7%, of low methoxyl (E440i) pectin. Example 40. An aerosol-generating article according to any one of Examples 27 to 39, wherein the gel composition preferably contains about 1.7% to about 3.1%, more preferably about 2.1% to about 2.9%, of lactic acid. Example 41. An aerosol-generating article according to any one of Examples 27 to 40, wherein the gel composition preferably contains from about 0.1% to about 7%, more preferably from about 0.1% to about 3%, of calactate. Example 42. An aerosol-generating article according to any one of Examples 27 to 41, wherein the gel composition comprises a cannabinoid compound. Example 43. An aerosol-generating article according to any one of Examples 27 to 42, wherein the gel composition is uniformly distributed in the flavor base. Example 44. An aerosol-generating article according to any one of Examples 27 to 42, wherein the gel composition is distributed in a variable manner in the flavor substrate. Example 45. The aerosol-generating article according to any one of Examples 27 to 44, wherein the gel composition has a viscosity of about 1,000,000 to about 1 Pascal per second, preferably 100,000 to 10 Pascal per second, preferably 10,000 to 1,000 Pascal per second, preferably 1,000 to 100 Pascal per second, preferably 500 to 200 Pascal per second. Example 46. An aerosol-generating article according to any one of Examples 1 to 26, wherein the flavor base comprises a flavor material. Example 47. An aerosol-generating article as described in Example 46, wherein the flavoring material is configured to be fluid-permeable when the temperature of the flavoring material is equal to or higher than the permeability transition temperature of the flavoring material, and the flavoring material is configured to be substantially fluid-impermeable when the temperature of the flavoring material is lower than the permeability transition temperature of the flavoring material, and preferably the permeability transition temperature of the flavoring material is a phase transition temperature of the flavoring material. Example 48. 48. The aerosol-generating article of Example 47, wherein the flavor material has a permeability transition temperature of 70 degrees Celsius to 80 degrees Celsius. Example 49. An aerosol-generating article described in any one of Examples 46 to 48, wherein the flavor material is configured to be fluid-permeable at 85 degrees Celsius and the flavor material is configured to be substantially fluid-impermeable at 20 degrees Celsius. Example 50. An aerosol-generating article according to any one of Examples 46 to 49, wherein the flavoring material is thermoreversible. Example 51. An aerosol-generating article according to any one of Examples 46 to 50, wherein the flavoring material preferably contains about 0.1% to about 4%, more preferably about 0.1% to 2% nicotine. Example 52. An aerosol-generating article according to any one of Examples 46 to 51, wherein the flavoring material comprises a flavoring agent. Example 53. 53. The aerosol-generating article of Example 52, wherein the flavoring agent comprises one or more of coffee derivative flavoring agents including menthol, caffeine, guanabolic acid, taurine, and glucuronolactone. Example 54. An aerosol-generating article according to any one of Examples 46 to 53, wherein the flavoring material preferably contains about 50% to about 75%, more preferably about 50% to about 65%, of glycerin. Example 55. An aerosol-generating article described in any one of Examples 46 to 54, wherein the flavoring material preferably comprises about 15% to about 35%, more preferably about 18% to about 32%, even more preferably about 20% to about 30%, and most preferably about 21% to about 27% hydroxypolymethylcellulose (HPMC). Example 56. An aerosol-generating article according to any one of Examples 46 to 55, wherein the flavoring material preferably comprises about 3% to about 10%, more preferably about 4% to about 7%, of agar. Example 57. An aerosol-generating article according to any one of Examples 46 to 56, wherein the flavoring material preferably comprises from about 0.1% to about 12%, more preferably from about 0.1% to 7%, of fiber. Example 58. An aerosol-generating article described in any one of Examples 46 to 57, wherein the flavoring material preferably comprises from about 0.1% to about 9%, more preferably from about 0.1% to 7%, of low methoxyl (E440i) pectin. Example 59. An aerosol-generating article according to any one of Examples 46 to 58, wherein the flavoring material preferably contains about 1.7% to about 3.1%, more preferably about 2.1% to about 2.9%, of lactic acid. Example 60. An aerosol-generating article according to any one of Examples 46 to 59, wherein the flavoring material preferably comprises from about 0.1% to about 7%, more preferably from about 0.1% to about 3%, of a colorant. Example 61. An aerosol-generating article according to any one of Examples 46 to 60, wherein the flavoring material comprises a cannabinoid compound. Example 62. An aerosol-generating article according to any one of Examples 46 to 61, wherein the flavoring material comprises hydroxypropyl methylcellulose, carboxymethylcellulose, a cellulose-based enhancer, or any combination thereof, preferably in an amount containing the weight percentages disclosed herein above. Example 63. An aerosol-generating article described in any one of Examples 46 to 62, wherein the flavoring material comprises a cellulose-based enrichment agent, the cellulose-based enrichment agent comprising cellulose fiber, microcrystalline cellulose, cellulose powder or any combination, preferably in an amount containing the weight percentages disclosed herein above. Example 64. An aerosol-generating article according to any one of Examples 1 to 63, wherein the resistance to deformation strength of the flavor base may be about 0.5 kgf to about 3 kgf, preferably about 1.3 kgf to about 2.7 kgf, and more preferably about 1.9 kgf to about 2.5 kgf. Example 65. The aerosol-generating article of any one of Examples 1 to 64, wherein the flavor substrate comprises an outer layer. Example 66. The aerosol-generating article of Example 65, wherein the outer layer is made of the same material as the remainder of the flavor substrate. Example 67. An aerosol-generating article described in any one of Examples 1 to 66, wherein the distance between the upstream end of the aerosol-forming substrate and the downstream end of the flavor substrate is less than about 40 millimeters, preferably less than about 30 millimeters, and even more preferably less than 20 millimeters. Example 68. An aerosol generating article described in any one of Examples 1 to 67, further comprising an adjustment member disposed on the tubular element and movable relative to the tubular element such that the adjustment member is configured to change the size of the air intake port. Example 69. 69. The aerosol-generating article of example 68, wherein the adjustment member and the tubular element are linearly movable relative to each other. Example 70. An aerosol-generating article as described in Example 68, wherein the adjustment member and the tubular element are configured to rotate relative to each other. Example 71. An aerosol-generating article as described in Example 68, wherein the adjustment member and the tubular element are configured to rotate and move linearly relative to each other, e.g., by a screw thread. Example 72. The aerosol-generating article according to any one of Examples 1 to 71, wherein the aerosol-forming substrate comprises a liquid component. Example 73. The aerosol-generating article of any one of Examples 1 to 72, wherein the aerosol-forming substrate comprises a solid component. Example 74. 4. The aerosol-generating article of any one of Examples 1 to 73, wherein the aerosol-forming substrate comprises a plant-based material, preferably a homogenized plant-derived material. Example 75. The aerosol-generating article of any one of Examples 1 to 74, wherein the aerosol-forming substrate comprises a non-tobacco material. Example 76. The aerosol-generating article of example 74 or example 75, wherein the aerosol-forming substrate comprises a tobacco material. Example 77. The aerosol-generating article of Example 76, wherein the aerosol-forming substrate comprises a solid homogenized tobacco material. Example 78. The aerosol-generating article of Example 77, wherein the aerosol-forming substrate comprises an assembly of at least one sheet of solid homogenized tobacco material. Example 79. 79. The aerosol-generating article of example 78, wherein at least one of the collection of sheets comprises a textured sheet, a crinkled sheet, or both. Example 80. An aerosol-generating article described in any one of Examples 77 to 79, wherein the solid homogenized tobacco material comprises strips of tobacco material. Example 81. The aerosol-generating article of any one of Examples 73 to 80 when dependent on Example 80, wherein the aerosol-forming substrate has a rod comprising a plurality of elongated tubular elements. Example 82. An aerosol-generating article as described in Example 81 when dependent on Example 77, wherein the plurality of elongated tubular elements comprise solid homogenized tobacco material. Example 83. An aerosol-generating article as described in Example 82, wherein at least one elongated tubular material comprises a rolled strip cut from a sheet or web of solid homogenized tobacco material. Example 84. The aerosol-generating article of any one of Examples 1 to 83, wherein the aerosol-forming substrate is a hollow tubular substrate defining an interior cavity. Example 85. The aerosol-generating article of any one of Examples 1 to 84, further comprising a layer of a thermally conductive material. Example 86. The aerosol-generating article according to any one of Examples 1 to 85, wherein the aerosol-forming substrate comprises an aerosol-forming body. Example 87. An aerosol generating device comprising a heater, the heater comprising a base heating element configured to heat an aerosol-generating article, and a downstream heating element disposed downstream of the base heating element. Example 88. An aerosol generating device as described in Example 87, wherein the heater comprises at least one resistive heating element. Example 89. An aerosol generating device as described in Example 88, wherein at least one resistive heating element comprises an electrically insulating substrate and one or more conductive tracks on the electrically insulating substrate. Example 90. An aerosol generating apparatus according to any one of Examples 87 to 89, wherein the heater comprises at least one induction heating device, each induction device including at least one inductor coil and at least one susceptor. Example 91. 91. The aerosol generating device of Example 90, wherein at least one inductor coil is positioned to generate a varying magnetic field upon receiving a varying current from a power source, the varying current being between about 5 kilohertz and about 500 kilohertz. Example 92. An aerosol generating device as described in Example 90, wherein at least one inductor coil is positioned to generate a varying magnetic field upon receiving a varying current from a power source, the varying current being between about 500 kilohertz and about 5 megahertz. Example 93. An aerosol generating device according to any one of Examples 90 to 92, wherein at least one inductor coil is a flat inductor coil, such as a flat inductor coil wound helically in a substantially plane. Example 94. An aerosol generating device described in any one of Examples 90 to 92, wherein at least one inductor coil is a tubular inductor coil, such as a tubular inductor coil wound helically around the longitudinal axis. Example 95. An aerosol generating device described in any one of Examples 90 to 94, wherein at least one inductor coil is formed from a conductive material. Example 96. The aerosol generating apparatus according to any one of Examples 90 to 95, wherein at least one susceptor is made of a conductive material. Example 97. The aerosol generating apparatus according to any one of Examples 90 to 96, wherein the at least one susceptor comprises a susceptor layer provided on a support, and the support preferably comprises a heat insulating material. Example 98. An aerosol generating device according to any one of Examples 90 to 97, wherein the heater comprises at least one resistive heating element and at least one inductive heating element. Example 99. The aerosol generating apparatus according to any one of Examples 87 to 98, wherein the substrate heating element is a substrate induction heating device and includes a substrate inductor coil and a substrate susceptor. Example 100. An aerosol generating device as described in Example 99, wherein the downstream heating element is a downstream induction heating device and includes a downstream inductor coil and a downstream susceptor. Example 101. An aerosol generating device as described in Example 99, wherein the downstream heating element is a resistive heating element. Example 102. The aerosol generating device according to any one of Examples 87 to 98, wherein the base heating element is a resistive heating element. Example 103. An aerosol generating device as described in Example 102, wherein the downstream heating element is a resistive heating element. Example 104. An aerosol generating device as described in Example 102, wherein the downstream heating element is a downstream induction heating device and includes a downstream inductor coil and a downstream susceptor. Example 105. The aerosol generating apparatus according to any one of Examples 87 to 98, wherein the downstream heating element is a downstream induction heating device and includes a downstream inductor coil and a downstream susceptor. Example 106. The aerosol generating device of Example 105, wherein the substrate heating element is a substrate induction heating device and includes a substrate inductor coil and a substrate susceptor. Example 107. The aerosol generating device of example 105, wherein the base heating element is a resistive heating element. Example 108. An aerosol generating device according to any one of Examples 87 to 98, wherein the downstream heating element is a resistive heating element. Example 109. 109. The aerosol generating apparatus of claim 108, wherein the substrate heating element is a substrate induction heating device and includes a substrate inductor coil and a substrate susceptor. Example 110. 109. The aerosol generating device of embodiment 108, wherein the base heating element is a resistive heating element. Example 111. The aerosol generating device according to any one of Examples 87 to 110, wherein the heater comprises an internal heating element. Example 112. An aerosol generating device according to any one of Examples 87 to 111, wherein the heater comprises an external heating element. Example 113. An aerosol generating device described in any one of Examples 111 or 112, wherein the downstream heating element and the substrate heating element are internal heating elements. Example 114. The aerosol generating device of example 111 or example 112, wherein the downstream heating element and the base heating element are external heating elements. Example 115. The aerosol generating device of example 111 or example 112, wherein the downstream heating element is an internal heating element and the base heating element is an external heating element. Example 116. An aerosol generating device described in any one of Examples 111 or 112, wherein the downstream heating element is an external heating element and the base heating element is an internal heating element. Example 117. The aerosol generating apparatus according to any one of Examples 87 to 116, further comprising a power source. Example 118. An aerosol generating device as described in Example 117, wherein the power source is electrically connected to the heater. Example 119. The aerosol generating device of any one of Examples 87 to 118, further comprising a cavity for receiving an aerosol-generating article. Example 120. An aerosol generating device described in any one of Examples 87 to 119, further comprising a device housing. Example 121. An aerosol generating device as described in example 119 and example 120, wherein the device housing at least partially defines a cavity for receiving an aerosol generating article. Example 122. An aerosol generating device according to any one of Examples 87 to 121, further comprising at least one device air inlet. Example 123. An aerosol generating device as described in Example 122 when dependent on Example 120, wherein the device housing includes at least one device air intake port. Example 124. The aerosol generating device of example 122 or example 123, wherein the at least one device air inlet comprises a substrate device air inlet. Example 125. The aerosol generation device according to any one of Examples 122 to 124, wherein at least one device air inlet comprises a downstream device air inlet. Example 126. The aerosol-generating article of any one of Examples 87 to 125, further comprising a controller. Example 127. An aerosol-generating article described in any one of Examples 87 to 126, further comprising a sensor configured to detect airflow indicating that a user is inhaling. Example 128. The aerosol-generating article of any one of Examples 87 to 127, further comprising at least one electrical connector. Example 129. An aerosol-generating article as described in Example 128, wherein at least one electrical connector includes an outer plug or socket, such as a USB plug or USB socket. Example 130. An aerosol generating system comprising the aerosol generating article according to any one of Examples 1 to 86, and the aerosol generating device according to any one of Examples 87 to 129.

[0287] These and other features and advantages of the present invention will become more apparent in the light of the following detailed description of preferred embodiments, given by way of illustrative and non-limiting example only, with reference to the accompanying drawings, in which:

[0288] FIG. 1 depicts a longitudinal cross-sectional view of an aerosol-generating article 10 having an upstream end 13 and a downstream end 14, the aerosol-generating article 10 defining a longitudinal direction between the upstream end 13 and the downstream end 14. The article 10 comprises an aerosol-forming substrate 11. In the embodiment of FIG. 1, a tubular element 12 is disposed immediately downstream of the aerosol-forming substrate 11 and extends along the longitudinal direction. The tubular element 12 includes an outer airflow channel 18 and an inner airflow channel 19. The tubular element 12 includes an air inlet 15 through which outside air may be drawn into the outer airflow channel 18. The tubular element 12 defines at least one airflow channel that establishes uninterrupted fluid communication between the upstream end 13 of the tubular element 12 and the downstream end 14 of the tubular element 12.

[0289] In the embodiment of Figure 1, the flavor substrate 16 is disposed longitudinally immediately downstream of the tubular element 12. In this embodiment, the flavor substrate 16 comprises a gel composition. However, other flavor materials different from the gel composition may be used in addition to or instead of the gel composition.

[0290] Providing the flavor substrate 16 downstream of the air inlet 15 contained in the outer airflow channel 18 allows for adjustment of the amount of airflow the flavor substrate 16 is supplied with. The gel composition helps to generate a uniform substrate upon heating of the flavor substrate 16, which can result in a very consistent aerosol to be entrained in the substrate aerosol generated by the aerosol-forming substrate 11 located upstream of the flavor substrate 16.

[0291] In the embodiment of FIG. 1, the permeable control element 20 is disposed within the outer airflow channel 18. The permeable control element 20 is configured to be fluid permeable when the temperature of the permeable control element is equal to or greater than the permeability transition temperature of the permeable control element 20, e.g., when the temperature of the permeable control element 20 is 85 degrees Celsius. Similarly, the permeable control element 20 is configured to be substantially fluid impermeable when the temperature of the permeable control element is less than the permeability transition temperature of the permeable control element, e.g., when the temperature of the permeable control element is 20 degrees Celsius. Thus, the permeable control element 20 may prevent fluid from flowing along the outer airflow channel 18 downstream of the permeable control element 20 when its temperature is below its permeability transition temperature (as depicted in FIG. 1) and allow fluid to flow along the outer airflow channel 18 downstream of the permeable control element 20 when its temperature is equal to or greater than its permeability transition temperature (as depicted in FIG. 2). This may result in a change in some properties of the aerosol-generating article 10. Heating the permeable control element 20 to its permeability transition temperature may result in an increase in the amount of airflow that can flow toward the downstream end 14 of the aerosol-generating article 10 and a decrease in the draw resistance of the aerosol-generating article 10, as the airflow is permitted to flow along the outer airflow channel 18. Similarly, the permeable control element 20 may be advantageously used to regulate the amount of airflow to which the flavor substrate 16 is provided.

[0292] In Figures 1-10, permeable control elements marked with dashed lines indicate that the permeable control element is substantially fluid impermeable, and permeable control elements marked with dots indicate that the permeable control element is fluid permeable.

[0293] In the embodiment of Figure 1, a spanning element 21 is provided in the outer airflow channel 18 to impede or regulate the flow of substrate aerosol into the outer airflow channel 18. The spanning element 21 may be a permeable control element. If the spanning element 21 is a permeable control element, then substrate aerosol may flow into the outer airflow channel 18 upon heating of the aerosol-forming substrate 11 if the temperature of the spanning element 21 is equal to or higher than the permeability transition temperature of the spanning element 21, e.g., 85 degrees Celsius. Similarly, substrate aerosol may be prevented from flowing into the outer airflow channel 18 upon heating of the aerosol-forming substrate 11 if the temperature of the spanning element 21 is lower than the permeability transition temperature of the spanning element 21, e.g., 20 degrees Celsius.

[0294] In this embodiment, the permeability control element 20 and the spanning element 21 comprise a gel composition, however, in alternative embodiments, the permeability control element 20 and the spanning element 21 comprise other suitable materials for achieving the desired change in permeability as a function of the temperature of the material.

[0295] The gel composition of the permeability control element 20, the spanning element 21, and / or the flavor material of the flavor substrate 16 may have 50-75 weight percent, preferably 50-65 weight percent, glycerin, 15-35 weight percent, preferably 20-30 weight percent, hydroxypolymethylcellulose (HPMC), 3-10 weight percent, preferably 4-7 weight percent, agar, 0-12 weight percent, preferably 0-7 weight percent, fiber, 0-9 weight percent, preferably 0-7 weight percent, low methoxyl (LM) (E440i) pectin, 1.7-3.1 weight percent, preferably 2.1-2.9 weight percent, lactic acid, 0 (zero)-7 weight percent, preferably 0 (zero)-3 weight percent, Ca-lactate, 0 (zero)-4 weight percent, preferably 0 (zero)-2 weight percent, nicotine, nicotine and flavorant, or a composition of the amount of flavorant.

[0296] The flavoring agent may be one or more of menthol extract, vanilla extract, and coffee derivative flavoring agents. Coffee derivative flavoring agents include one or more of caffeine, guarana, taurine, and glucuronolactone. When flavoring agents are present in the gel composition, they are preferably present at 0.2 to 4 weight percent, more preferably 0.4 to 2 weight percent.

[0297] Examples of compositions of gel compositions that may be used in any of the permeability control elements, flavor substrates, or spanning elements described herein are shown below in Table 1. Table 1 shows the weight percentages of each component of the gel compositions. [Table 1] TIFF2024505990000002.tif133170

[0298] The gel composition described above can provide a predictable composition form during storage or during transportation from manufacture to the consumer. The gel composition can substantially maintain its shape. The gel composition maintains its state at room temperature (about 21 degrees Celsius). The gel composition is configured to be in a solid state within a temperature range that covers the normal ambient temperature of use of the aerosol-generating article. A suitable range of ambient temperatures can be from about -20 degrees Celsius to about 70 degrees Celsius. The overall state of the gel composition can be predominantly solid or can be in a gel solid state and fluid impermeable. Above about 70 degrees Celsius, the overall state of the composition can be predominantly liquid and fluid permeable.

[0299] When in a solid state, the gel composition described above can be configured to have sufficient resistance to deformation to provide the flavor substrate with mechanical stability for handling during manufacture, transportation, and use of the aerosol-generating article. The gel composition can have a resistance to deformation strength of 0.5 kgf to 3.0 kgf. The resistance to deformation is preferably 1.3 kgf to 2.7 kgf, more preferably 1.9 kgf to 2.5 kgf. The mechanical strength of the gel composition can be adjusted to a desired range by adjusting the amount of low methoxyl (LM) pectin in the composition. The use of LM pectin for this purpose depends on the specific composition formulation and can be used in a proportion of 0.1 to 9 weight percent, preferably 0.1 to 7 weight percent, and most preferably 1 to 3 weight percent.

[0300] The composition of the gel composition may be distributed in a variable manner within the flavor substrate. In an alternative embodiment, the composition may have a homogenous distribution. The flavor substrate may include an outer layer useful for giving the flavor substrate the required shape to be placed within the aerosol-generating article. The outer layer may be a shell. The remaining portion of the flavor substrate may be a core. The flavor substrate including the core and the outer layer is manufactured by first depositing the core including the remaining portion of the flavor substrate and then depositing a layer on the core to form the outer layer. There are several types of manufacturing process that can be applied. The core layer and the outer layer may be manufactured by extrusion. A tubular core may be produced and the next step may be an extrusion process in which the gel composition is uniformly deposited on the outer surface of the tubular core. The outer layer can be made of the same gel composition as the remaining portion of the flavor substrate. The core layer and the outer layer may have the same properties. The core layer and the outer layer may have different properties. In one example, the core is about 5 to about 20 percent, more preferably about 10 to about 15 percent, softer and has lower mechanical strength than the shell, which is the harder outer layer. Alternatively, or additionally, if the gel composition includes a flavoring, the outer layer (shell) may be flavorless.

[0301] In the embodiment shown in FIGS. 1 and 2, the permeability control element 20 and the spanning element 21 each comprise flavorless composition A or flavorless composition B as described above in Table 1.

[0302] In the embodiment shown in FIGS. 1 and 2, the flavor material of the flavor substrate 16 comprises flavorful composition A or flavorful composition B as described above in Table 1.

[0303] In the embodiment of FIGS. 1-10, filter 17 is disposed longitudinally immediately downstream of tubular element 12 , and mouthpiece 22 is disposed immediately downstream of filter 17 .

[0304] The gel composition of the flavor substrate 16 in the embodiment of FIG. 1 may also be configured to be fluid permeable when the temperature of the gel composition is equal to or higher than the permeability transition temperature of the gel composition, as represented by the dots in FIG. 1, and to be substantially fluid impermeable when the temperature of the gel composition is lower than the permeability transition temperature of the gel composition, as represented by the dashed line in FIG. 2. Thus, the flavor substrate 16 may also be a permeable control element. Thus, the flavor substrate may have a gel composition as described above for the permeability control element. The gel composition of the embodiment of FIG. 1 may, in other embodiments, be configured to be substantially fluid impermeable at any operating temperature applied to the flavor substrate by the aerosol generating device. In the latter embodiment, the flavor substrate does not typically extend across the entire cross section of one or more airflow channels to allow airflow to flow toward the downstream end downstream of the aerosol generating article. The flavor substrate may be fluid permeable and configured to allow fluid flowing along the airflow channel to flow downstream of the flavor substrate 16 when the temperature of the flavor substrate is equal to or higher than the permeability transition temperature of the flavor substrate, or may be substantially fluid impermeable and configured to substantially prevent fluid flowing along the airflow channel from flowing downstream of the flavor substrate 16 when the temperature of the flavor substrate is lower than the permeability transition temperature of the flavor substrate, the flavor substrate being a gel composition.

[0305] Figure 2 is a longitudinal cross-sectional view of the aerosol-generating article of Figure 1, showing the moment when the permeable control element 20, the spanning element 21, and the flavor substrate 16 are at temperatures at which they are each fluid-permeable, as represented by dots in the figure. Similarly, the aerosol-forming substrate 11 is heated to generate substrate aerosol that is entrained in the ambient air entering the aerosol-generating article 10 on its upstream end 13. A significant proportion of the substrate aerosol flows along the inner airflow channel 19 of the tubular element 12. In Figure 2, the spanning element 21 is fluid-permeable, so that a portion of the substrate aerosol flows along the outer airflow channel 18. In an embodiment in which the spanning element is permanently fluid-impermeable at any operating temperature of the aerosol-generating article, all substrate aerosol generated upon heating of the aerosol-forming substrate flows along the inner airflow channel.

[0306] In FIG. 2, ambient air is drawn into the outer airflow channel 18 through the air inlet 15. At the moment shown in FIG. 2, the flow of ambient air and substrate aerosol reaches the flavor substrate 16, because the permeable control element 20 is fluid permeable. The flavor substrate 16 is also fluid permeable and is further heated to form a flavor aerosol. The flavor aerosol is entrained in the flow of ambient air and substrate aerosol to form an aerosol that can be inhaled by the user. The entrained aerosol is filtered by the filter 17 and delivered to the user through the mouthpiece 22.

[0307] FIG. 3 shows a longitudinal cross-sectional view of an aerosol-generating article 10 in which, unlike the aerosol-generating article of FIG. 1, a flavor substrate 16 containing a gel composition is positioned within an outer airflow channel 18 between an air inlet 15 and a permeable control element 20.

[0308] In this embodiment, the flavor substrate 16 is a permeable control element. Thus, as shown in FIG. 3, the flavor substrate 16 prevents airflow from flowing along the outer airflow channel 18 downstream of the flavor substrate 16 when its temperature is below the permeability transition temperature of the gel composition. Similarly, the permeable control element 20 prevents airflow from flowing along the outer airflow channel 18 downstream of the permeable control element 20 when its temperature is below the permeability transition temperature of the permeable control element 20, as also shown in FIG. 3. The flavor substrate 16 allows airflow to flow along the outer airflow channel 18 downstream of the flavor substrate 16 when its temperature is equal to or higher than the permeability transition temperature of the gel composition, as shown in FIG. 4. The permeable control element 20 allows airflow to flow along the outer airflow channel 18 downstream of the permeable control element 20 when its temperature is equal to or higher than the permeability transition temperature of the permeable control element 20, as also shown in FIG. 4.

[0309] The spanning element 21 is disposed in the outer airflow channel 18 upstream of the air inlet 15. The spanning element 21 may be a permeability control element. If the spanning element 21 is a permeability control element, the substrate aerosol may flow into the outer airflow channel 18 upon heating of the aerosol-forming substrate 11 when the temperature of the spanning element 21 is equal to or higher than the permeability transition temperature of the spanning element 21.

[0310] Figure 4 is a longitudinal cross-sectional view of the aerosol-generating article of Figure 3, showing the moment when the permeable control element 20, the spanning element 21, and the flavor substrate 16 are at temperatures at which they are each fluid-permeable, as represented by dots in the figure. Similarly, the aerosol-forming substrate 11 is heated to generate substrate aerosol that is entrained in the ambient air entering the aerosol-generating article 10 on its upstream end 13. A significant proportion of the substrate aerosol flows along the inner airflow channel 19 of the tubular element 12. In Figure 4, the spanning element 21 is fluid-permeable, so that a portion of the substrate aerosol flows along the outer airflow channel 18. In an embodiment where the spanning element is permanently fluid-impermeable, all substrate aerosol generated upon heating of the aerosol-forming substrate flows along the inner airflow channel.

[0311] In FIG. 4, ambient air is drawn into the outer airflow channel 18 through the air inlet 15. The flavor substrate 16 is also fluid permeable and is further heated to form a flavor aerosol in the outer airflow channel 18. The flavor aerosol is entrained in the flow of ambient air and in part of the substrate aerosol in the outer airflow channel 18. The resulting aerosol reaches the filter 17, since the permeable control element 20 arranged downstream of the flavor substrate 16 is fluid permeable at the moment shown in FIG. 6. The aerosol is then entrained in part of the substrate aerosol flowing along the inner airflow channel 19, forming an aerosol that can be inhaled by the user. The aerosol is delivered to the user through the mouthpiece 22.

[0312] In the embodiments shown in FIGS. 3 and 4, the permeability control element 20 and the spanning element 21 each comprise either the flavorless composition A or the flavored composition B described above in Table 1.

[0313] In the embodiment shown in FIGS. 3 and 4, the flavor material of the flavor substrate 16 comprises flavorful composition A or flavorful composition B as described above in Table 1.

[0314] Figure 5 shows a longitudinal cross-sectional view of an aerosol-generating article 10 in which, unlike the aerosol-generating article of Figure 3, the flavor substrate 16 containing the gel composition is the only permeable control element located downstream of the air inlet 15 in the outer airflow channel 18. Thus, as shown in Figure 5, the flavor substrate 16 prevents airflow from flowing along the outer airflow channel 18 downstream of the tubular element 12 when its temperature is below the permeability transition temperature of the gel composition. Similarly, the flavor substrate 16 allows airflow to flow along the outer airflow channel 18 downstream of the tubular element 12 when its temperature is equal to or higher than the permeability transition temperature of the gel composition, as shown in Figure 6.

[0315] Figure 6 is a longitudinal cross-sectional view of the aerosol-generating article of Figure 5, showing the moment when the spanning element 21 and the flavour substrate 16 are at their respective fluid-permeable temperatures, as represented by the dots in the figure. Similarly, the aerosol-forming substrate 11 is heated to generate substrate aerosol that is entrained in the ambient air entering the aerosol-generating article 10 on its upstream end 13. A significant proportion of the substrate aerosol flows along the inner airflow channel 19 of the tubular element 12. In Figure 6, the spanning element 21 is fluid-permeable, so that a portion of the substrate aerosol also flows along the outer airflow channel 18. In an embodiment where the spanning element is permanently fluid-impermeable, all substrate aerosol generated upon heating of the aerosol-forming substrate flows along the inner airflow channel.

[0316] In FIG. 6, outside air is drawn through the air inlet 15 into the outer airflow channel 18. The flavor substrate 16, which is fluid permeable at the moment of FIG. 6, is further heated to form a flavor aerosol in the outer airflow channel 18. The flavor aerosol is thus entrained in the flow of outside air and a portion of the substrate aerosol in the outer airflow channel 18. The resulting aerosol is entrained in a portion of the substrate aerosol flowing along the inner airflow channel 19 to form an aerosol inhalable by the user. The aerosol is filtered by the filter 17 and delivered to the user through the mouthpiece 22.

[0317] In the embodiment shown in FIGS. 5 and 6, spanning element 21 comprises either flavorless composition A or flavorless composition B as described above in Table 1.

[0318] In the embodiment shown in FIGS. 5 and 6, the flavor material of the flavor substrate 16 comprises flavorful composition A or flavorful composition B as described above in Table 1.

[0319] 7 shows a longitudinal cross-sectional view of an aerosol-generating article 10 in which, unlike the aerosol-generating articles of the three preceding embodiments, the outer airflow channel 18 does not include an air inlet. In the embodiment of FIG. 7, a spanning element 21 is provided in the outer airflow channel 18 upstream of the flavor substrate 16, and a permeable control element 20 is disposed downstream of the flavor substrate 16. The flavor substrate 16 in this embodiment is a permeable control element. Thus, airflow along the outer airflow channel 18 downstream of the flavor substrate 16 and the permeable control element 20 can be prevented or allowed by changing the permeability of the flavor substrate 16 and the permeable control element 20, respectively, as in the embodiment of FIG. 3. The spanning element 21 can be a permeable control element. If the spanning element 21 is a permeable control element, it can prevent or allow airflow to flow along the outer airflow channel 18. In particular, when the temperature of spanning element 21 is equal to or higher than the permeability transition temperature of spanning element 21 , upon heating of aerosol-forming substrate 11 , substrate aerosol may flow into outer airflow channel 18 .

[0320] Figure 8 is a longitudinal cross-sectional view of the aerosol-generating article of Figure 7, showing the moment when the permeable control element 20, the spanning element 21, and the flavor substrate 16 are at temperatures at which they are each fluid-permeable, as represented by the dots in the figure. Similarly, the aerosol-forming substrate 11 is heated to generate substrate aerosol that is entrained in the ambient air entering the aerosol-generating article 10 on its upstream end 13. A significant proportion of the substrate aerosol flows along the inner airflow channel 19 of the tubular element 12. In Figure 8, the spanning element 21 is fluid-permeable, so that a portion of the substrate aerosol also flows along the outer airflow channel 18. In an embodiment where the spanning element is permanently fluid-impermeable, all substrate aerosol generated upon heating of the aerosol-forming substrate flows along the inner airflow channel.

[0321] At the moment of Fig. 8, the flavor substrate 16 is fluid permeable and further heated to form a flavor aerosol in the outer airflow channel 18. Thus, the flavor aerosol is entrained with a portion of the substrate aerosol in the outer airflow channel 18, without being mixed with the ambient air drawn directly into the airflow channel 18. The resulting aerosol is entrained with a portion of the substrate aerosol flowing along the inner airflow channel 19, forming an aerosol that can be inhaled by the user. The aerosol is filtered by the filter 17 and delivered to the user through the mouthpiece 22.

[0322] In the embodiments shown in FIGS. 7 and 8, the permeability control element 20 and the spanning element 21 each comprise flavorless composition A or flavorless composition B as described above in Table 1.

[0323] In the embodiment shown in FIGS. 7 and 8, the flavor material of the flavor substrate 16 comprises flavorful composition A or flavorful composition B as described above in Table 1.

[0324] 9 shows a longitudinal cross-sectional view of the aerosol-generating article 10 in which the flavor substrate 16 occupies the entire length of the outer airflow channel 18. Thus, in this embodiment, the flavor substrate 16 is the only permeability control element. The flavor substrate 16 also plays the role of the spanning element of the previous embodiment. The flavor substrate 16 prevents airflow from flowing along the outer airflow channel 18 downstream of the tubular element 12 into the outer airflow channel 18 when the temperature of the flavor substrate 16 is lower than the permeability transition temperature of the gel composition, as shown by the dashed line in FIG. 9. The flavor substrate 16 allows airflow to flow along the outer airflow channel 18 downstream of the tubular element 12 into the outer airflow channel 18 when heated to a temperature equal to or above the permeability transition temperature of the gel composition, as shown in FIG. 10.

[0325] Figure 10 is a longitudinal cross-sectional view of the aerosol-generating article of Figure 9, showing a moment when the flavor substrate 16 is at a temperature at which the gel composition is fluid-permeable, as represented by the dots in the figure. Similarly, the aerosol-forming substrate 11 is heated to generate a substrate aerosol that is entrained in the ambient air entering the aerosol-generating article 10 on its upstream end 13. A significant proportion of the substrate aerosol flows along the inner airflow channel 19 of the tubular element 12. In Figure 10, since the flavor substrate 16 is fluid-permeable, a portion of the substrate aerosol also flows along the outer airflow channel 18. In an embodiment where the spanning element is permanently fluid-impermeable, all the substrate aerosol generated upon heating of the aerosol-forming substrate flows along the inner airflow channel.

[0326] In Figure 10, the flavor substrate 16 is heated to form a flavor aerosol in the outer airflow channel 18. The flavor aerosol is thus entrained with a portion of the substrate aerosol in the outer airflow channel 18, rather than being mixed with ambient air drawn directly into the airflow channel 18. The resulting aerosol is entrained with a portion of the substrate aerosol flowing along the inner airflow channel 19, forming an aerosol that can be inhaled by the user. The aerosol is filtered by the filter 17 and delivered to the user through the mouthpiece 22.

[0327] In the embodiment shown in FIGS. 9 and 10, the flavor material of the flavor substrate 16 comprises flavorful composition A or flavorful composition B as described above in Table 1.

[0328] 11 shows a cross-sectional view of an aerosol generating system comprising an aerosol generating device 200 and an aerosol-generating article 10. The aerosol-generating article 10 may be any of the articles of FIGS.

[0329] The aerosol generating device 200 comprises a substantially cylindrical device housing 207 having a shape and size similar to a conventional cigar.

[0330] The aerosol generating device 200 further comprises a power source 201 in the form of a rechargeable nickel-cadmium battery, a controller 202 in the form of a printed circuit board including a microprocessor, an electrical connector 203, and a heater 204. The heater 204 comprises a substrate heating element 205 configured to heat the aerosol-forming substrate 11, and a downstream heating element 206 disposed downstream of the substrate heating element 205. The downstream heating element 206 is configured to heat the flavor substrate 16, and in a corresponding embodiment, the permeability control element 20 and the spanning element 21.

[0331] 11, the substrate heating element 205 and downstream heating element 206 are substrate induction heating device 205 and downstream induction heating device 206, respectively, each including at least one inductor coil and at least one susceptor, however, other forms of heating elements, such as resistive heating elements, may also be used.

[0332] The power supply 201, controller 202, and inductive heating devices 205, 206 are all contained within a device housing 207. The inductive heating devices 205, 206 of the aerosol generation device 200 are disposed at a proximal end of the device 200. The electrical connector 203 is disposed at a distal end of the device housing 207.

[0333] As used herein, the term "proximal" refers to the user end or oral end of an aerosol generating device or aerosol generating article. The proximal end of a component of an aerosol generating device or aerosol generating article is the end of the component closest to the user end or the oral end of the aerosol generating device or aerosol generating article. As used herein, the term "distal" refers to the end opposite the proximal end.

[0334] The controller 202 is configured to control the supply of power from the power source 201 to the induction heating devices 205, 206. The controller 202 further includes a DC / AC inverter including a class D power amplifier. The controller 202 is also configured to control the recharging of the power source 201 from the electrical connector 203. The controller 202 further includes a puff sensor (not shown) configured to detect when a user withdraws an aerosol-generating article received within the device cavity 208.

[0335] The substrate induction heating device 205 includes a substrate inductor coil 209 and a substrate susceptor 210. The substrate susceptor 210 is a blade susceptor configured to penetrate into the aerosol-forming substrate 11 and provide internal heating to the aerosol-forming substrate 11. The substrate inductor coil 209 is tubular in the embodiment of FIG. 11 and is concentrically disposed around a portion of the cavity 208 configured to receive the aerosol-forming substrate 11.

[0336] The substrate inductor coil 209 is connected to a controller 202 and a power source 201, and the controller 202 is configured to supply a varying current to the substrate inductor coil 209. When a varying current is supplied to the substrate inductor coil 209, the substrate inductor coil 209 generates a varying magnetic field, which heats the substrate susceptor 210 by induction.

[0337] The downstream induction heating device 206 includes a downstream inductor coil 211 and a downstream susceptor 212. The downstream susceptor 212 is a tubular susceptor configured to be concentrically positioned around a section of the aerosol-generating article 10 that includes a flavor substrate 16 to provide external heating to the flavor substrate 16. If the aerosol-generating article 10 includes a permeability control element 20, a spanning element 21, or both, the downstream susceptor 212 is also configured to be concentrically positioned around a section of the aerosol-generating article 10 that includes the permeability control element 20 and the spanning element 21. The downstream inductor coil 211 is tubular in the embodiment of FIG. 11 and is concentrically positioned around the downstream susceptor 212.

[0338] The downstream inductor coil 211 is connected to the controller 202 and the power source 201, and the controller 202 is configured to supply a varying current to the downstream inductor coil 211. When a varying current is supplied to the downstream inductor coil 211, the downstream inductor coil 211 generates a varying magnetic field, which heats the downstream susceptor 212 by induction.

[0339] As depicted in Fig. 12, the device housing 207 also defines a substrate device air inlet 213 proximate the distal end of the cavity 208 for receiving the aerosol-generating article 10. The substrate device air inlet 213 is configured to allow ambient air to be drawn into the device housing 207 towards the aerosol-forming substrate 11. The device housing 207 also defines a downstream device air inlet 214. The downstream device air inlet 214 is configured to allow ambient air to be drawn into the device housing 202 towards the air inlet 15 of the tubular element 12 of the aerosol-generating article 10 in embodiments in which the tubular element 12 comprises an air inlet 15. For this reason, the downstream device air inlet 214 is configured to substantially coincide with the air inlet 15 of the tubular element 12 when the aerosol-generating article 10 is fully introduced into the device cavity 208.

[0340] Figure 13 shows an external view of the aerosol generating device 200 of Figures 11 and 12. The outer surfaces of the substrate induction heating device 205 and the downstream induction heating device 206 are shown in Figure 13. Downstream of the substrate induction heating device 205, the aerosol generating device 200 includes a button 212 configured to switch on and off the heater 204 components.

[0341] The downstream induction heating device 206 is also depicted in FIG. 14 as being separate from the remainder of the aerosol generation device 200 to illustrate that in this embodiment, the downstream induction heating device 206 may be removably attached to the remainder of the aerosol generation device 200.

[0342] FIG. 15 is an exploded view of the downstream induction heating apparatus 206 of FIG.

Claims

1. 1. An aerosol-generating article having an upstream end and a downstream end, the aerosol-generating article defining a longitudinal axis between the upstream end and the downstream end, the aerosol-generating article comprising: an aerosol-forming substrate; a tubular element disposed downstream of the aerosol-forming substrate and extending along the longitudinal direction, the tubular element comprising an inner tube and an outer tube, the outer tube being disposed around the inner tube, an outer airflow channel being bounded in the longitudinal direction by the inner tube and the outer tube, an inner airflow channel being bounded in the longitudinal direction by the inner tube, and at least the inner airflow channel being adapted for the substrate aerosol to flow towards the downstream end; a flavor substrate located downstream of the aerosol-forming substrate; at least one permeability control element comprising a gel composition; the at least one permeability control element is configured to be fluid permeable when the temperature of the at least one permeability control element is equal to or greater than the permeability transition temperature of the permeability control element; the at least one permeability control element is configured to be substantially fluid impermeable when the temperature of the at least one permeability control element is below the permeability transition temperature of the permeability control element; an aerosol-generating article, wherein the at least one permeability control element is disposed within the outer airflow channel and configured to prevent fluid from flowing along the outer airflow channel downstream of the at least one permeability control element when the temperature of the at least one permeability control element is lower than the permeability transition temperature of the permeability control element, and configured to allow fluid to flow along the outer airflow channel downstream of the permeability control element when the temperature of the at least one permeability control element is equal to or higher than the permeability transition temperature of the permeability control element.

2. 1. An aerosol-generating article having an upstream end and a downstream end, the aerosol-generating article defining a longitudinal axis between the upstream end and the downstream end, the aerosol-generating article comprising: an aerosol-forming substrate; a tubular element disposed downstream of the aerosol-forming substrate and extending along the longitudinal direction, the tubular element comprising an inner tube and an outer tube, the outer tube being disposed around the inner tube, an outer airflow channel being bounded in the longitudinal direction by the inner tube and the outer tube, an inner airflow channel being bounded in the longitudinal direction by the inner tube, and at least the inner airflow channel being adapted for the substrate aerosol to flow towards the downstream end; a flavor substrate located downstream of the aerosol-forming substrate; and at least one permeable control element comprising a gel composition, the at least one permeable control element being disposed within the outer airflow channel and configured to prevent fluid from flowing along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is 20 degrees Celsius, and to allow fluid to flow along the outer airflow channel downstream of the permeable control element when the temperature of the at least one permeable control element is 85 degrees Celsius.

3. 3. The aerosol-generating article according to claim 1, wherein the flavor substrate is disposed within the outer airflow channel.

4. 4. The aerosol-generating article of claim 3, wherein the flavor substrate is a permeable control element.

5. 5. The aerosol-generating article according to claim 3, wherein a permeability control element is positioned downstream of the flavor substrate.

6. 6. The aerosol-generating article of claim 1, wherein a spanning element is disposed within the outer airflow channel upstream of the flavor substrate.

7. 7. The aerosol-generating article of claim 6, wherein the spanning element is a permeability control element.

8. 5. The aerosol-generating article of claim 4, wherein the flavor substrate extends longitudinally along the entire outer airflow channel.

9. 9. The aerosol-generating article of claim 1, further comprising an air inlet configured to allow intake of outside air into the outer airflow channel.

10. 10. An aerosol-generating article according to claim 9 when dependent on claim 6 or 7, wherein the air inlet is located downstream of the spanning element.

11. The aerosol-generating article according to any one of claims 9 to 10, wherein the flavor substrate is disposed downstream of the air inlet.

12. 12. The aerosol-generating article according to any one of claims 1 to 11, further comprising a filter located downstream of the tubular element.

13. 13. An aerosol-generating article according to any one of claims 1 to 12, wherein the permeability transition temperature of the at least one permeability control element is a phase transition temperature of the at least one permeability control element.

14. 14. The aerosol-generating article according to any one of claims 1 to 13, wherein the flavor substrate comprises a flavor material such as a gel composition.

15. 1. An aerosol generating system comprising: An aerosol-generating article according to any one of claims 1 to 14; 1. An aerosol generating system comprising: an aerosol generating device comprising a heater, the heater comprising a base heating element configured to heat the aerosol-generating article, and a downstream heating element disposed downstream of the base heating element.

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