Aerosol-generating system with multiple aerosol-generating segments

Abstract

An aerosol-generating system is provided that includes an aerosol-generating device for use with an aerosol-generating article. An aerosol-generating device includes a heating chamber for receiving an aerosol-generating article and a heater assembly disposed along a portion of the heating chamber defining a heating zone. The aerosol-generating system also includes an aerosol-generating article for receipt in the heating chamber of the aerosol-generating device. An aerosol-generating article comprises a first aerosol-generating segment comprising a first aerosol-generating substrate and a second aerosol-generating segment comprising a second aerosol-generating substrate. The aerosol-generating system is configured such that at least 90% of the length of the second aerosol-generating segment is within the heating zone when the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device; wherein the first aerosol-generating section is located upstream of the second aerosol-generating section, and a length of the first aerosol-generating section is less than a length of the second aerosol-generating section.

Description

Technical Field

[0001] The present invention relates to an aerosol generating system comprising an aerosol generating device and an aerosol generating article. In particular, the present invention relates to an aerosol generating system, wherein the aerosol generating device comprises a first aerosol generating segment and a second aerosol generating segment. Background Art

[0002] Aerosol generating systems comprising an aerosol generating device and corresponding aerosol generating articles are known in the art. For example, it is known that a system in which an aerosol generating article is heated by an aerosol generating device to generate an aerosol. The aerosol generating article may include an aerosol generating substrate that is heated rather than burned, such as a tobacco-containing substrate. Typically, in such systems, an aerosol is generated by transferring heat from a heat source of an aerosol generating device to a physically separated aerosol generating substrate or material that is a part of an aerosol generating article. In use, the aerosol generating substrate may be in contact with the heat source of the aerosol generating device, located within the heat source, around the heat source, or located downstream of the heat source. During use of the aerosol generating system, volatile compounds are released from the aerosol generating substrate by heat transfer from the heat source, and are entrained in the air drawn by the aerosol generating article. When the released compound cools, the compound condenses to form an aerosol.

[0003] Many prior art documents disclose aerosol generating devices for consuming aerosol generating articles. Such devices include, for example, electrically heated aerosol generating devices, wherein an aerosol is generated by transferring heat from one or more electrical heater elements of the aerosol generating device to an aerosol generating substrate of the heated aerosol generating article. For example, electrically heated aerosol generating devices including internal heater blades adapted to be inserted into an aerosol generating substrate have been proposed.

[0004] It is known to provide aerosol-generating systems in which an aerosol-generating article is configured for use with a specific aerosol-generating device.

[0005] For example, an aerosol generating article of the prior art may include an upstream element upstream of the aerosol generating substrate. This upstream element may be present to prevent the aerosol generating substrate from falling out of the aerosol generating article and to control the suction resistance of the article. Since the aerosol generating substrate does not extend to the upstream end of the aerosol generating article, it is not necessary to heat the entire length of the aerosol generating article. Therefore, the corresponding aerosol generating device may include a heater, which is positioned and sized to heat only the aerosol generating substrate of the aerosol generating article when the aerosol generating article is fully received in the heating chamber. For example, in the case where the aerosol generating device includes a heating chamber, the heater may not extend to the upstream end of the heating chamber.

[0006] However, providing an aerosol generating device configured for use only with a specific corresponding aerosol generating article may mean that the device is less effective when used with other aerosol generating articles. For example, it may be desirable to use an aerosol generating device with an aerosol generating article having a larger aerosol generating substrate.

[0007] Therefore, there is a need for an aerosol generating system in which an aerosol generating device can be effectively used with an alternative aerosol generating article to generate an aerosol. In particular, there is a need for an aerosol generating system comprising an aerosol generating device and an aerosol generating article, wherein the aerosol generating device is adapted to heat an aerosol generating substrate of the aerosol generating article to a temperature sufficient to generate an aerosol. Summary of the invention

[0008] According to one aspect of the present disclosure, an aerosol generating system is provided. The aerosol generating system may include an aerosol generating device for use with an aerosol generating article. The aerosol generating device may include a heating chamber for receiving the aerosol generating article. The aerosol generating device may include a heater assembly arranged along a portion of the heating chamber defining a heating zone. The aerosol generating system may also include an aerosol generating article for receiving in the heating chamber of the aerosol generating device. The aerosol generating article may include a first aerosol generating segment, the first aerosol generating segment including a first aerosol generating substrate. The aerosol generating article may include a second aerosol generating segment, the second aerosol generating segment including a second aerosol generating substrate. The aerosol generating system may be configured such that when the aerosol generating article is fully received in the heating chamber of the aerosol generating device, no more than 50% of the length of the first aerosol generating segment is within the heating zone. The aerosol generating system may be configured such that when the aerosol generating article is fully received within the heating chamber of the aerosol generating device, at least 90% of the length of the second aerosol generating segment is within the heating zone. The first aerosol generating segment may be located upstream of the second aerosol generating segment. The length of the first aerosol generating segment may be less than the length of the second aerosol generating segment.

[0009] According to the present invention, an aerosol generating system is provided, which includes an aerosol generating device for use with an aerosol generating article. The aerosol generating device includes a heating chamber for receiving the aerosol generating article and a heater assembly arranged along a portion of the heating chamber defining a heating zone. The aerosol generating device also includes an aerosol generating article for receiving in the heating chamber of the aerosol generating device. The aerosol generating article includes a first aerosol generating segment and a second aerosol generating segment, the first aerosol generating segment including a first aerosol generating substrate, and the second aerosol generating segment including a second aerosol generating substrate. The aerosol generating system is configured so that when the aerosol generating article is fully received in the heating chamber of the aerosol generating device, at least 90% of the length of the second aerosol generating segment is within the heating zone; wherein the first aerosol generating segment is located upstream of the second aerosol generating segment, and the length of the first aerosol generating segment is less than the length of the second aerosol generating segment.

[0010] In other words, when the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, a majority of the second aerosol-generating segment is located within the heating zone, close to the heater assembly. This may mean that the second aerosol-generating segment receives effective direct heating from the heater assembly.

[0011] In contrast, most of the first aerosol generating segment may be located outside the heating zone, further away from the heater assembly. This may mean that the first aerosol generating segment receives less effective indirect heating from the heater assembly. For example, the first aerosol generating segment may be heated by heat conduction from the second aerosol generating segment.

[0012] In use, this may mean that the second aerosol generating segment is heated to a higher temperature than the first aerosol generating segment.This may also mean that when the heater assembly is activated, the temperature of the second aerosol generating segment increases faster than the temperature of the first aerosol generating segment.

[0013] Thus, providing a first aerosol generating segment comprising a first aerosol generating substrate and a second aerosol generating segment comprising a second aerosol generating substrate may advantageously allow the aerosol generating substrate in each aerosol generating segment to be configured to generate an aerosol at a temperature reached by the respective aerosol generating segment during use. For example, the first aerosol generating substrate may be configured to generate an aerosol at a lower temperature than the second aerosol generating substrate.

[0014] This may advantageously allow the total length of the aerosol-generating substrate to be greater than the length of the heating zone without compromising the efficiency of aerosol generation, as the total length of the aerosol-generating substrate may be divided into a portion configured to generate aerosol at a lower temperature and a portion configured to generate aerosol at a higher temperature. This arrangement may also allow a greater total amount of the aerosol-generating substrate in the aerosol-generating article to be used with an aerosol-generating device whose heating zone is shorter than the desired total length of the aerosol-generating substrate.

[0015] In a preferred embodiment, an aerosol generating system is provided, which includes an aerosol generating device for use with an aerosol generating article. The aerosol generating device includes a heating chamber for receiving the aerosol generating article and a heater assembly arranged along a portion of the heating chamber defining a heating zone. The aerosol generating device also includes an aerosol generating article for receiving in the heating chamber of the aerosol generating device. The aerosol generating article includes a first aerosol generating segment and a second aerosol generating segment, the first aerosol generating segment including a first aerosol generating substrate, and the second aerosol generating segment including a second aerosol generating substrate. The aerosol generating system is configured so that when the aerosol generating article is fully received in the heating chamber of the aerosol generating device, no more than 50% of the length of the first aerosol generating segment is within the heating zone, and at least 90% of the length of the second aerosol generating segment is within the heating zone. The first aerosol generating substrate comprises at least one aerosol former, and wherein the aerosol former content of the first aerosol generating substrate is less than 30 weight %; and a second aerosol generating segment, which is located upstream of the first aerosol generating segment and comprises a second aerosol generating substrate, wherein the second aerosol generating substrate comprises at least one aerosol former, and wherein the aerosol former content of the second aerosol generating substrate is at least 40 weight % on a dry weight basis.

[0016] In a preferred embodiment, an aerosol generating system is provided, which includes an aerosol generating device for use with an aerosol generating article. The aerosol generating device includes a heating chamber for receiving the aerosol generating article and a heater assembly arranged along a portion of the heating chamber defining a heating zone. The aerosol generating device also includes an aerosol generating article for receiving in the heating chamber of the aerosol generating device. The aerosol generating article includes a first aerosol generating segment and a second aerosol generating segment, the first aerosol generating segment including a first aerosol generating substrate, and the second aerosol generating segment including a second aerosol generating substrate. The aerosol generating system is configured so that when the aerosol generating article is fully received in the heating chamber of the aerosol generating device, no more than 50% of the length of the first aerosol generating segment is within the heating zone, and at least 90% of the length of the second aerosol generating segment is within the heating zone. The density of the second aerosol generating substrate is at least 1.2 times the density of the first aerosol generating substrate.

[0017] In a preferred embodiment, an aerosol generating system is provided, which includes an aerosol generating device for use with an aerosol generating article. The aerosol generating device includes a heating chamber for receiving the aerosol generating article and a heater assembly arranged along a portion of the heating chamber defining a heating zone. The aerosol generating device also includes an aerosol generating article for receiving in the heating chamber of the aerosol generating device. The aerosol generating article includes a first aerosol generating segment and a second aerosol generating segment, the first aerosol generating segment including a first aerosol generating substrate, and the second aerosol generating segment including a second aerosol generating substrate. The aerosol generating system is configured so that when the aerosol generating article is fully received in the heating chamber of the aerosol generating device, no more than 50% of the length of the first aerosol generating segment is within the heating zone, and at least 90% of the length of the second aerosol generating segment is within the heating zone. The first aerosol generating substrate comprises at least one aerosol forming agent, and wherein the aerosol forming agent content of the first aerosol generating substrate is less than 30% by weight; and a second aerosol generating segment, the second aerosol generating segment is at a position upstream of the first aerosol generating segment and comprises a second aerosol generating substrate, wherein the second aerosol generating substrate comprises at least one aerosol forming agent, wherein the aerosol forming agent content of the second aerosol generating substrate is at least 40% by weight on a dry weight basis. The density of the second aerosol generating substrate is at least 1.2 times the density of the first aerosol generating substrate.

[0018] In a preferred embodiment, an aerosol generating system is provided, which includes an aerosol generating device for use with an aerosol generating article. The aerosol generating device includes a heating chamber for receiving the aerosol generating article and a heater assembly arranged along a portion of the heating chamber defining a heating zone. The aerosol generating device also includes an aerosol generating article for receiving in the heating chamber of the aerosol generating device. The aerosol generating article includes a first aerosol generating segment and a second aerosol generating segment, the first aerosol generating segment including a first aerosol generating substrate, and the second aerosol generating segment including a second aerosol generating substrate. The aerosol generating system is configured so that when the aerosol generating article is completely received in the heating chamber of the aerosol generating device, no more than 50% of the length of the first aerosol generating segment is within the heating zone, and at least 90% of the length of the second aerosol generating segment is within the heating zone. The aerosol forming agent content of the first aerosol generating substrate is less than 30% by weight, and the first aerosol generating substrate has a density of less than 400 mg / cm3. The second aerosol-generating substrate comprises at least one aerosol former, wherein the aerosol-forming agent content of the second aerosol-generating substrate is at least 40 wt% on a dry weight basis, and wherein the density of the second aerosol-generating substrate is greater than 500 mg / cm3.

[0019] In a preferred embodiment, an aerosol generating system is provided, which includes an aerosol generating device for use with an aerosol generating article. The aerosol generating device includes a heating chamber for receiving the aerosol generating article and a heater assembly arranged along a portion of the heating chamber defining a heating zone. The aerosol generating device also includes an aerosol generating article for receiving in the heating chamber of the aerosol generating device. The aerosol generating article includes a first aerosol generating segment and a second aerosol generating segment, the first aerosol generating segment including a first aerosol generating substrate, and the second aerosol generating segment including a second aerosol generating substrate. The aerosol generating system is configured so that when the aerosol generating article is fully received in the heating chamber of the aerosol generating device, no more than 50% of the length of the first aerosol generating segment is within the heating zone, and at least 90% of the length of the second aerosol generating segment is within the heating zone. The first aerosol generating substrate includes at least one aerosol former, and wherein the aerosol former content of the first aerosol generating substrate is less than 30% by weight. The second aerosol-generating substrate comprises at least one aerosol-forming agent, wherein the aerosol-forming agent content of the second aerosol-generating substrate is at least 40 wt% on a dry weight basis, and wherein the ratio of the length of the first aerosol-generating segment to the length of the second aerosol-generating segment does not exceed 0.5.

[0020] In a preferred embodiment, an aerosol generating system is provided, which includes an aerosol generating device for use with an aerosol generating article. The aerosol generating device includes a heating chamber for receiving the aerosol generating article and a heater assembly arranged along a portion of the heating chamber defining a heating zone. The aerosol generating device also includes an aerosol generating article for receiving in the heating chamber of the aerosol generating device. The aerosol generating article includes a first aerosol generating segment and a second aerosol generating segment, the first aerosol generating segment including a first aerosol generating substrate, and the second aerosol generating segment including a second aerosol generating substrate. The aerosol generating system is configured so that when the aerosol generating article is fully received in the heating chamber of the aerosol generating device, no more than 50% of the length of the first aerosol generating segment is within the heating zone, and at least 90% of the length of the second aerosol generating segment is within the heating zone. The first aerosol generating segment has a length of about 5 mm. The second aerosol generating segment has a length of about 12 mm.

[0021] As used herein with reference to the present invention, the term "heating zone" refers to the portion of the heating chamber extending in the longitudinal direction between the upstream end of the heater assembly and the downstream end of the heater assembly.

[0022] As used herein with reference to the present invention, the term "heater assembly" refers to the component of an aerosol-generating device that is responsible for heating the aerosol-generating substrate of an aerosol-generating article. As explained in more detail below, the heater assembly may directly heat the aerosol-generating substrate, which may be the case if the heater assembly includes a resistive heater. The heater assembly may indirectly heat the aerosol-generating substrate, which may be the case if the heater assembly includes an induction coil.

[0023] As used herein with reference to the present invention, the term "longitudinal" refers to the direction corresponding to the principal axis of an aerosol-generating article or aerosol-generating device, extending between the upstream and downstream ends of the aerosol-generating article or aerosol-generating device.

[0024] As used herein with reference to the present invention, the terms "upstream" and "downstream" describe the relative position of an element or part of an element of an aerosol generating system relative to the direction in which aerosol is transported through the aerosol generating article during use. During use, air is drawn through the aerosol generating article in a longitudinal direction.

[0025] As used herein with reference to the present invention, the term "length" refers to the dimension of a component of an aerosol generating system in the longitudinal direction from the most upstream point of the component to the most downstream point of the component. For example, it may be used to refer to the dimension of an aerosol generating substrate or any elongated tubular element in the longitudinal direction.

[0026] The heating chamber of the aerosol generating device may comprise an open downstream end and a closed upstream end. In use, the upstream end of the aerosol generating device may be inserted into the open downstream end of the heating chamber. In use, the upstream end of the aerosol generating article may abut the upstream end of the heating chamber. Alternatively, the upstream end of the aerosol generating article may abut another component within the heating chamber to prevent the aerosol generating article from moving further upstream.

[0027] As used herein with reference to the present invention, the term "fully received" refers to the position when the aerosol-generating article is inserted into the heating chamber to the greatest extent possible. This may be when the upstream end of the aerosol-generating article abuts the upstream end of the heating chamber. Alternatively, this may be when the upstream end of the aerosol-generating article abuts another component within the heating chamber to prevent the aerosol-generating article from moving further upstream. When the aerosol-generating article is "fully received" in the heating chamber, a portion of the aerosol-generating article may protrude from the open downstream end of the aerosol-generating article. This may be the case, for example, where the length of the aerosol-generating article is greater than the length of the heating chamber, or where the length of the aerosol-generating article is greater than the distance between the downstream end of the heating chamber and a component (if present) within the heating chamber to prevent the aerosol-generating article from moving further upstream.

[0028] When the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, no more than 50% of the length of the first aerosol-generating segment may be within the heating zone.

[0029] For example, when the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, no more than 50%, no more than 40%, no more than 30%, no more than 20%, no more than 10%, or no more than 5% of the length of the first aerosol-generating segment may be within the heating zone. In some embodiments, when the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, none of the first aerosol-generating segment is disposed within the heating zone. In other words, the entire length of the first aerosol-generating segment may be disposed outside the heating zone.

[0030] When the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, the upstream end of the heating zone may be aligned with the downstream end of the first aerosol-generating segment.

[0031] When the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, at least 5% of the length of the first aerosol-generating segment is within the heating zone.

[0032] For example, when the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, at least 10%, at least 20%, at least 30% or at least 40% of the length of the first aerosol-generating segment may be within the heating zone.

[0033] When the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, at least 90% of the length of the second aerosol-generating segment may be within the heating zone.

[0034] For example, when the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, at least 95% of the length of the second aerosol-generating segment may be within the heating zone. In some embodiments, when the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, the entire length of the second aerosol-generating segment may be disposed within the heating zone. In this case, the length of the heating zone is the same as or greater than the length of the second aerosol-generating segment.

[0035] When the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, the upstream end of the heating zone may be aligned with the upstream end of the second aerosol-generating segment. When the aerosol-generating article is fully received within the heating chamber of the aerosol-generating device, the downstream end of the heating zone may be aligned with the downstream end of the second aerosol-generating segment.

[0036] In some embodiments, when the aerosol generating article is fully received in the heating chamber of the aerosol generating device, the upstream end of the second aerosol generating segment is aligned with the upstream end of the heating zone, and the downstream end of the second aerosol generating segment is aligned with the downstream end of the heating zone, wherein the first aerosol generating segment is not arranged in the heating zone at all.

[0037] The first aerosol generating segment may be located downstream of the second aerosol generating segment. The first aerosol generating segment may be located upstream of the second aerosol generating segment. This may be the case where the aerosol generating article of the present invention is used with an aerosol generating device that is designed to be used with a different aerosol generating article that includes an upstream element. In this case, the first aerosol generating segment may replace all or part of the upstream element in the aerosol generating article.

[0038] As described in more detail below, the aerosol-generating article may further comprise an upstream element.

[0039] Alternatively, the upstream end of the first aerosol-generating segment may define the upstream end of the aerosol-generating article.

[0040] In this case, the aerosol-generating article does not include an upstream element as described above. This may be the case where an aerosol-generating article of the invention is used with an aerosol-generating device that is designed to be used with a different aerosol-generating article that includes an upstream element. In this case, the first aerosol-generating segment may replace the upstream element in the aerosol-generating article.

[0041] The upstream end of the second aerosol generating segment may be in direct contact with the downstream end of the first aerosol generating segment.Substantially the entire surface of the downstream end of the first aerosol generating segment may abut the upstream end of the second aerosol generating segment.

[0042] This may advantageously improve heat transfer from the second aerosol generating segment disposed primarily within the heating zone to the first aerosol generating segment disposed primarily outside the heating zone.

[0043] Alternatively, the upstream end of the second aerosol generating segment may be separated from the downstream end of the first aerosol generating segment.

[0044] The length of the first aerosol generating segment may be smaller than the length of the second aerosol generating segment.

[0045] This may advantageously mean that a greater proportion of the total aerosol-generating substrate is disposed within the heating region during use.This may advantageously improve the generation of aerosol by the aerosol-generating system.

[0046] The ratio of the length of the first aerosol generating segment to the length of the second aerosol generating segment may be no greater than 1. The ratio of the length of the first aerosol generating segment to the length of the second aerosol generating segment may be less than 1.

[0047] For example, the ratio of the length of the first aerosol generating segment to the length of the second aerosol generating segment may be no greater than 0.8, no greater than 0.6, or no greater than 0.5.

[0048] The ratio of the length of the first aerosol generating segment to the length of the second aerosol generating segment may be at least 0.1.

[0049] For example, the ratio of the length of the first aerosol-generating segment to the length of the second aerosol-generating segment may be at least 0.2, at least 0.3, or at least 0.4.

[0050] The ratio of the length of the first aerosol generating segment to the length of the second aerosol generating segment may be between 0.1 and 1, between 0.2 and 0.8, between 0.3 and 0.6, or between 0.4 and 0.5.

[0051] The ratio of the length of the first aerosol generating segment to the length of the second aerosol generating segment may be about 0.4 or about 0.42.

[0052] In other embodiments, the ratio of the length of the first aerosol generating segment to the length of the second aerosol generating segment may be greater than 1. The ratio of the length of the first aerosol generating segment to the length of the second aerosol generating segment may be about 1.

[0053] The length of the second aerosol generating segment may be at least 3 mm greater than the length of the first aerosol generating segment. For example, the second aerosol generating segment may be at least 4 mm greater, at least 5 mm greater, or at least 6 mm greater than the length of the first aerosol generating segment.

[0054] The length of the second aerosol generating segment may be no more than 12 mm greater than the length of the first aerosol generating segment. For example, the second aerosol generating segment may be no more than 10 mm greater, no more than 9 mm greater, or no more than 8 mm greater than the length of the first aerosol generating segment.

[0055] The length of the second aerosol generating segment may be approximately 7 mm longer than the length of the first aerosol generating segment.

[0056] The first aerosol-generating segment may have a length of at least 2 mm. For example, the first aerosol-generating segment may have a length of at least 3 mm or at least 4 mm.

[0057] The first aerosol-generating segment may have a length of no more than 8 mm. For example, the first aerosol-generating segment may have a length of no more than 7 mm or no more than 6 mm.

[0058] The first aerosol generating segment may have a length of between 2 mm and 8 mm, between 3 mm and 7 mm, or between 4 mm and 6 mm.

[0059] The first aerosol generating segment may have a length of approximately 5 mm.

[0060] The second aerosol generating segment may have a length of at least 8 mm. For example, the second aerosol generating segment may have a length of at least 9 mm or at least 10 mm.

[0061] The second aerosol generating segment may have a length of no more than 16 mm. For example, the second aerosol generating segment may have a length of no more than 15 mm or no more than 14 mm.

[0062] The second aerosol generating segment may have a length of between 8 mm and 16 mm, between 9 mm and 15 mm, or between 10 mm and 14 mm.

[0063] The second aerosol generating segment may have a length of approximately 12 mm.

[0064] The combined length of the first aerosol generating segment and the second aerosol generating segment may be at least 10 mm. For example, the combined length of the first aerosol generating segment and the second aerosol generating segment may be at least 12 mm, at least 14 mm, or at least 16 mm.

[0065] The combined length of the first aerosol generating segment and the second aerosol generating segment may not exceed 24 mm. For example, the combined length of the first aerosol generating segment and the second aerosol generating segment may not exceed 22 mm, not exceed 20 mm, or not exceed 18 mm.

[0066] The combined length of the first aerosol generating segment and the second aerosol generating segment may be between 10 mm and 24 mm. For example, the combined length of the first aerosol generating segment and the second aerosol generating segment may be between 12 mm and 22 mm, between 14 mm and 20 mm, or between 16 mm and 18 mm.

[0067] The combined length of the first aerosol generating segment and the second aerosol generating segment may be approximately 17 mm.

[0068] The first aerosol-generating segment may have a length of at least 10 mm. For example, the first aerosol-generating segment may have a length of at least 15 mm or at least 18 mm.

[0069] The first aerosol generating segment may have a length of no more than 30 mm. For example, the first aerosol generating segment may have a length of no more than 25 mm or no more than 20 mm.

[0070] The first aerosol generating segment may have a length of between 10 mm and 30 mm, between 15 mm and 25 mm, or between 18 mm and 20 mm.

[0071] The first aerosol generating segment may have a length of about 18.5 mm. The first aerosol generating segment may have a length of about 17 mm.

[0072] The second aerosol generating segment may have a length of at least 10 mm. For example, the second first aerosol generating segment may have a length of at least 15 mm or at least 18 mm.

[0073] The second aerosol generating segment may have a length of no more than 30 mm. For example, the second aerosol generating segment may have a length of no more than 25 mm or no more than 20 mm.

[0074] The second aerosol generating segment may have a length of between 10 mm and 30 mm, between 15 mm and 25 mm, or between 18 mm and 20 mm.

[0075] The second aerosol generating segment may have a length of about 18.5 mm. The second aerosol generating segment may have a length of about 17 mm.

[0076] The combined length of the first aerosol generating segment and the second aerosol generating segment may be at least 20 mm. For example, the combined length of the first aerosol generating segment and the second aerosol generating segment may be at least 25 mm, at least 30 mm, or at least 35 mm.

[0077] The combined length of the first aerosol generating segment and the second aerosol generating segment may not exceed 55 mm. For example, the combined length of the first aerosol generating segment and the second aerosol generating segment may not exceed 50 mm, not exceed 45 mm, or not exceed 40 mm.

[0078] The combined length of the first aerosol generating segment and the second aerosol generating segment may be between 20 mm and 55 mm. For example, the combined length of the first aerosol generating segment and the second aerosol generating segment may be between 25 mm and 50 mm, between 30 mm and 45 mm, or between 35 mm and 40 mm.

[0079] The combined length of the first aerosol generating segment and the second aerosol generating segment may be about 37 mm. The combined length of the first aerosol generating segment and the second aerosol generating segment may be about 34 mm.

[0080] The first aerosol generating segment and the second aerosol generating segment may have any outer diameter. The first aerosol generating segment and the second aerosol generating segment may have substantially the same outer diameter, which common diameter may be referred to as the diameter of the aerosol generating segment. One or both of the first aerosol generating segment and the second aerosol generating segment may have an outer diameter that is substantially equal to the outer diameter of the aerosol generating article.

[0081] The "outer diameter" of an aerosol-generating segment may be calculated as the average of multiple measurements of the diameter of the aerosol-generating segment taken at different locations along the length of the aerosol-generating segment.

[0082] Preferably, the aerosol generating segment has an outer diameter of at least about 5 mm. More preferably, the aerosol generating segment has an outer diameter of at least about 6 mm. Even more preferably, the aerosol generating segment has an outer diameter of at least about 7 mm.

[0083] The aerosol generating segment preferably has an outer diameter of less than or equal to about 12 mm. More preferably, the aerosol generating segment has an outer diameter of less than or equal to about 10 mm. Even more preferably, the aerosol generating segment has an outer diameter of less than or equal to about 8 mm.

[0084] In general, it has been observed that the smaller the diameter of the aerosol generating segment, the lower the temperature required to raise the core temperature of the aerosol generating segment to release a sufficient amount of vaporizable substance from the aerosol generating substrate to form a desired amount of aerosol.

[0085] The aerosol-generating device may comprise a body.The body or housing of the aerosol-generating device may define a heating chamber for removably receiving an aerosol-generating article at a downstream end of the device.

[0086] The length of the heating chamber may be between 15 mm and 80 mm. Preferably, the length of the heating chamber is between 20 mm and 70 mm. More preferably, the length of the heating chamber is between 25 mm and 60 mm. More preferably, the length of the heating chamber is between 25 mm and 50 mm.

[0087] The length of the heating chamber may be between 25 mm and 29 mm. Preferably, the length of the heating chamber is between 25 mm and 29 mm. More preferably, the length of the heating chamber is between 26 mm and 29 mm. Even more preferably, the length of the heating chamber is 27 mm or 28 mm.

[0088] The length of the heating chamber may be the same as or greater than the combined length of the first aerosol generating segment and the second aerosol generating segment. Preferably, the length of the heating chamber is such that when the aerosol generating article is fully received in the heating chamber, at least 75% of the combined length of the first aerosol generating segment and the second aerosol generating segment is inserted or received in the heating chamber of the device. More preferably, the length of the heating chamber is such that when the aerosol generating article is fully received in the heating chamber, at least 80% of the combined length of the first aerosol generating segment and the second aerosol generating segment is inserted or received in the heating chamber. More preferably, the length of the heating chamber is such that when the aerosol generating article is fully received in the heating chamber, at least 90% of the combined length of the first aerosol generating segment and the second aerosol generating segment is inserted or received in the heating chamber. This maximizes the length of the first aerosol generating segment and the second aerosol generating segment, along which the first aerosol generating substrate and the second aerosol generating substrate can be heated during use, thereby optimizing aerosol generation from the aerosol generating substrate and reducing waste.

[0089] The length of the heating chamber may be such that the downstream segment or a portion thereof is configured to protrude from the heating chamber when the aerosol-generating article is fully received within the heating chamber. The length of the heating chamber may be such that a portion of the downstream segment, such as a hollow tubular cooling element or a downstream filter segment, is configured to protrude from the heating chamber when the aerosol-generating article is fully received within the heating chamber. The length of the heating chamber may be such that a portion of the downstream segment, such as a hollow tubular cooling element or a downstream filter segment, is configured to be received within the heating chamber when the aerosol-generating article is fully received within the heating chamber.

[0090] When the aerosol-generating article is fully received within the heating chamber, at least 25% of the length of the downstream segment may be inserted or received within the heating chamber. When the aerosol-generating article is fully received within the heating chamber, at least 30% of the length of the downstream segment may be inserted or received within the heating chamber.

[0091] When the aerosol-generating article is fully received within the heating chamber, at least 30% of the length of the hollow tubular element can be inserted or received within the heating chamber. When the aerosol-generating article is fully received within the heating chamber, at least 40% of the length of the hollow tubular element can be inserted or received within the heating chamber. When the aerosol-generating article is fully received within the heating chamber, at least 50% of the length of the hollow tubular element can be inserted or received within the heating chamber. Hollow tubular elements of various lengths are described in more detail within the present disclosure.

[0092] Optimizing the amount or length of the aerosol-generating article inserted into the heating chamber of the aerosol-generating device may enhance the ability of the article to prevent accidental falling out during use. In particular, during heating of the aerosol-generating substrate, the substrate may shrink such that its outer diameter may have decreased, thereby reducing the extent to which an insertion portion of the article inserted into the device can frictionally engage with the heating chamber. The insertion portion of the article or the portion of the article configured to be received within the heating chamber may have the same length as the heating chamber.

[0093] The diameter of the heating chamber may be between 4 mm and 10 mm. The diameter of the heating chamber may be between 5 mm and 9 mm. The diameter of the heating chamber may be between 6 mm and 8 mm. The diameter of the heating chamber may be between 6 mm and 7 mm.

[0094] The diameter of the heating chamber may be substantially the same as or larger than the diameter of the aerosol-generating article.The diameter of the heating chamber may be the same as the diameter of the aerosol-generating article so as to establish a close fit with the aerosol-generating article.

[0095] The heating chamber may be configured to establish a close fit with the aerosol generating article received in the heating chamber. A close fit may refer to a snug fit. The aerosol generating device may include a peripheral wall. Such a peripheral wall may define the heating chamber. The peripheral wall defining the heating chamber may be configured to engage with the aerosol generating article received in the heating chamber in a close fit, such that when received in the heating chamber, there is substantially no gap or void between the peripheral wall defining the heating chamber and the aerosol generating article.

[0096] Such a close fit may create an air-tight fit or configuration between the heating chamber and the aerosol-generating article received therein.

[0097] With such an airtight construction, there is substantially no gap or empty space between the peripheral wall defining the heating chamber and the aerosol-generating article through which air can flow.

[0098] The close fit with the aerosol-generating article may be established along the entire length of the heating chamber or along a portion of the length of the heating chamber.

[0099] The aerosol generating device may include an airflow channel extending between a channel inlet and a channel outlet. The airflow channel may be configured to establish fluid communication between the interior of the heating chamber and the exterior of the aerosol generating device. The airflow channel of the aerosol generating device may be defined within a housing of the aerosol generating device so as to enable fluid communication between the interior of the heating chamber and the exterior of the aerosol generating device. When the aerosol generating article is received in the heating chamber, the airflow channel may be configured to provide airflow into the article so as to deliver the generated aerosol to a user drawing from a downstream end of the article.

[0100] The airflow channel of the aerosol generating device may be defined within or by the peripheral wall of the housing of the aerosol generating device. In other words, the airflow channel of the aerosol generating device may be defined within the thickness of the peripheral wall or by the inner surface of the peripheral wall, or a combination of both. The airflow channel may be partially defined by the inner surface of the peripheral wall and may be partially defined within the thickness of the peripheral wall. The inner surface of the peripheral wall defines the peripheral boundary of the heating chamber.

[0101] The airflow channel of the aerosol generating device may extend from an inlet at the mouth end of the aerosol generating device to an outlet at the mouth end of the device.The airflow channel may extend in a direction parallel to the longitudinal axis of the aerosol generating device.

[0102] The heater assembly may include any suitable type of heating element or heater. The heater assembly may include at least one of a resistive heating element and an inductive heating assembly. The heater assembly may include an external heater or external heating element.

[0103] The heater assembly may heat the aerosol-generating article externally when the aerosol-generating article is received within the aerosol-generating device.Such an external heater assembly may confine the aerosol-generating article when the aerosol-generating article is inserted or received within a heating chamber of the aerosol-generating device.

[0104] In some embodiments, the heater assembly is arranged to heat an outer surface of at least one of the aerosol-generating substrates.The heater assembly may be located within a heating chamber.

[0105] The heater assembly may include at least one resistive heating element. The at least one resistive heating element may be any suitable type of resistive heating element. In some embodiments, the heater assembly includes only one resistive heating element. In some embodiments, the heater assembly includes a plurality of resistive heating elements. The heater may include at least one resistive heating element. Preferably, the heater assembly includes a plurality of resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing a plurality of resistive heating elements electrically connected in a parallel arrangement may facilitate delivering the desired power to the heater while reducing or minimizing the voltage required to provide the desired power. Advantageously, reducing or minimizing the voltage required to operate the heater may facilitate reducing or minimizing the physical size of the power supply.

[0106] Suitable materials for forming at least one resistive heating element include, but are not limited to, semiconductors such as doped ceramics, electrically "conductive" ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, metal alloys, and composite materials made of ceramic materials and metallic materials. Such composite materials may include doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, alloys containing nickel, cobalt, chromium, aluminum-titanium-zirconium, hafnium, niobium, molybdenum, tantalum, tungsten, tin, gallium, manganese, and iron, and superalloys based on nickel, iron, cobalt, stainless steel, Timetal®, and iron-manganese-aluminum-based alloys.

[0107] In some embodiments, at least one resistive heating element comprises one or more stamped portions of a resistive material such as stainless steel. Alternatively, at least one resistive heating element may comprise a heating wire or filament, such as Ni-Cr (nickel-chromium), platinum, tungsten or alloy wire.

[0108] In some embodiments, the at least one heating element comprises an electrically insulating substrate, wherein the at least one resistive heating element is disposed on the electrically insulating substrate.

[0109] The electrically insulating substrate may include any suitable material. For example, the electrically insulating substrate may include one or more of: paper, glass, ceramic, anodized metal, coated metal, and polymer. The ceramic may include mica, aluminum oxide (Al2O3), or zirconium oxide (ZrO2). The polymer may include polyimide. Preferably, the electrically insulating substrate has a thermal conductivity of less than or equal to about 40 W / m·Kelvin, preferably less than or equal to about 20 W / m·Kelvin, and ideally less than or equal to about 2 W / m·Kelvin.

[0110] Where the heater assembly comprises a resistive heating element, the resistive heating element may define at least a portion of the heating chamber, thereby defining the heating zone.

[0111] In some embodiments, the heater assembly includes an induction heating assembly. The induction heating assembly may include an inductor coil. The aerosol generating device may include a power supply configured to provide a high-frequency oscillating current to the inductor coil. As used herein, a high-frequency oscillating current means an oscillating current having a frequency between about 500 kHz and about 30 MHz. Advantageously, the aerosol generating device may include a DC / AC inverter for converting a DC current supplied by a DC power supply into an alternating current. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field when receiving a high-frequency oscillating current from a power supply. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field in a heating chamber. In some embodiments, the inductor coil may substantially define the heating chamber. The inductor coil may extend at least partially along the length of the heating chamber, thereby defining a heating zone.

[0112] The heater assembly may include an induction heating element. The induction heating element may be a susceptor element. As used herein with reference to the present invention, the term "susceptor element" refers to an element comprising a material capable of converting electromagnetic energy into heat. When the susceptor element is located in an alternating electromagnetic field, the susceptor is heated. The heating of the susceptor element may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0113] The susceptor element may be arranged such that when the aerosol generating article is received in the heating chamber of the aerosol generating device, the oscillating electromagnetic field generated by the inductor coil induces a current in the susceptor element, thereby causing the susceptor element to heat up. In these embodiments, the aerosol generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H field strength) between 1 kiloamperes per meter and 5 kiloamperes per meter (kA m), preferably between 2 kA / m and 3 kA / m, for example about 2.5 kA / m. Preferably, the electrically operated aerosol generating device is capable of generating a fluctuating electromagnetic field having a frequency between 1 MHz and 30 MHz, for example between 1 MHz and 10 MHz, for example between 5 MHz and 7 MHz.

[0114] In these embodiments, the susceptor element is preferably positioned to contact the aerosol generating substrate. In some embodiments, the susceptor element is located in the aerosol generating device. In these embodiments, the susceptor element may be located in a heating chamber. The aerosol generating device may include only one susceptor element. The aerosol generating device may include a plurality of susceptor elements. In some embodiments, the susceptor element is preferably arranged to heat the outer surface of the aerosol generating substrate.

[0115] Where the heater assembly includes both an induction coil and an induction heating element, the heating zone is defined as the longitudinal space between the most upstream portion of the induction coil and the induction heating element, and the longitudinal space between the most downstream portion of the induction coil and the induction heating element.

[0116] The susceptor element may comprise any suitable material. The susceptor element may be formed of any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol generating substrate. Suitable materials for the elongated susceptor element include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and metal material composites. Some susceptor elements include metal or carbon. Advantageously, the susceptor element may include or consist of a ferromagnetic material, such as ferritic iron, ferromagnetic alloys (e.g., ferromagnetic steel or stainless steel), ferromagnetic particles, and ferrites. Suitable susceptor elements may be aluminum or include aluminum. The susceptor element preferably comprises about greater than 5%, preferably greater than 20%, more preferably greater than 50%, or greater than 90% ferromagnetic or paramagnetic material. Some elongated susceptor elements may be heated to a temperature in excess of 250 degrees Celsius.

[0117] The susceptor element may comprise a non-metallic core with a metallic layer disposed thereon.For example, the susceptor element may comprise a metallic track formed on the outer surface of a ceramic core or substrate.

[0118] As described in more detail below, in some embodiments where the aerosol-generating device comprises an induction coil, the aerosol-generating article may comprise at least one susceptor element.

[0119] In some embodiments, the aerosol generating device may comprise at least one resistive heating element and at least one inductive heating component. In some embodiments, the aerosol generating device may comprise a combination of a resistive heating element and an inductive heating component.

[0120] The first aerosol-generating substrate has a first density and the second aerosol-generating substrate has a second density, which may be greater than the first density.

[0121] As used herein with reference to the present invention, the term "density" refers to the bulk density of the first aerosol-generating substrate and the second aerosol-generating substrate. This can be calculated by measuring the total weight of the aerosol-generating substrate and dividing it by the volume of the segment of the aerosol-generating substrate (excluding any packaging).

[0122] Providing a first aerosol generating substrate with a lower density can advantageously provide improved aerosol delivery of an aerosol generating article. The first aerosol generating substrate with a lower density will heat up faster than if it had a higher density due to its lower thermal inertia. This is advantageous because most of the first aerosol generating substrate is not located in the heating zone and will therefore be heated to a lower temperature than the second aerosol generating substrate. Although most of the aerosol generating substrate will be subjected to indirect heating, providing a lower density in the first aerosol generating substrate can advantageously allow efficient aerosol generation in the first aerosol generating substrate. In contrast, because the second aerosol generating substrate is heated more efficiently, the second aerosol generating substrate that is primarily located in the heating zone can have a higher density. The higher density in the second aerosol generating substrate can advantageously allow continuous aerosol delivery throughout the duration of using the aerosol generating article.

[0123] Preferably, the first aerosol-generating substrate has a density of at least 100 mg / cm3. More preferably, the density of the first aerosol-generating substrate is at least 125 mg / cm3. More preferably, the density of the first aerosol-generating substrate is at least 150 mg / cm3. Even more preferably, the density of the first aerosol-generating substrate is at least 200 mg / cm3.

[0124] Providing a first aerosol-generating substrate having a density of at least 100 mg / cm3 can advantageously prevent the first aerosol-generating substrate from falling out of or otherwise moving from the upstream end of the first aerosol-generating segment, wherein the upstream end of the first aerosol-generating segment defines the upstream end of the aerosol-generating article.

[0125] Preferably, the first aerosol-generating substrate has a density of less than 400 mg / cm3. More preferably, the density of the first aerosol-generating substrate is less than 375 mg / cm3. More preferably, the density of the first aerosol-generating substrate is less than 350 mg / cm3. More preferably, the density of the first aerosol-generating substrate is less than 300 mg / cm3.

[0126] For example, the density of the first aerosol-generating substrate may be between 100 mg / cm3 and 400 mg / cm3, or between 125 mg / cm3 and 375 mg / cm3, or between 150 mg / cm3 and 350 mg / cm3, or between 200 mg / cm3 and 300 mg / cm3.

[0127] Preferably, the second aerosol-generating substrate has a density of at least 500 mg / cm3. More preferably, the density of the second aerosol-generating substrate is at least 525 mg / cm3. More preferably, the density of the second aerosol-generating substrate is at least 550 mg / cm3. Even more preferably, the density of the second aerosol-generating substrate is at least 600 mg / cm3.

[0128] Preferably, the second aerosol-generating substrate has a density of less than 1000 mg / cm3. More preferably, the density of the second aerosol-generating substrate is less than 900 mg / cm3. More preferably, the density of the second aerosol-generating substrate is less than 800 mg / cm3. More preferably, the density of the second aerosol-generating substrate is less than 750 mg / cm3.

[0129] For example, the density of the second aerosol-generating substrate may be between 500 mg / cm3 and 1000 mg / cm3, or between 525 mg / cm3 and 900 mg / cm3, or between 550 mg / cm3 and 880 mg / cm3, or between 600 mg / cm3 and 750 mg / cm3.

[0130] Preferably, the density of the second aerosol generating substrate is at least 25 mg / cm3 higher than the density of the first aerosol generating substrate, or at least 50 mg / cm3 higher than the density of the first aerosol generating substrate, or at least 75 mg / cm3 higher than the density of the first aerosol generating substrate, or at least 100 mg / cm3 higher than the density of the first aerosol generating substrate. More preferably, the density of the second aerosol generating substrate is at least 150 mg / cm3 higher than the density of the first aerosol generating substrate. More preferably, the density of the second aerosol generating substrate is at least 200 mg / cm3 higher than the density of the first aerosol generating substrate. The density of the second aerosol generating substrate may be up to 500 mg / cm3 higher than the density of the first aerosol generating substrate.

[0131] Preferably, the density of the second aerosol generating substrate is at least 1.05 times the density of the first aerosol generating substrate, or at least 1.1 times the density of the first aerosol generating substrate, or at least 1.2 times the density of the first aerosol generating substrate. More preferably, the density of the second aerosol generating substrate is at least 1.3 times the density of the first aerosol generating substrate, or at least 1.4 times the density of the first aerosol generating substrate, or at least 1.5 times the density of the first aerosol generating substrate. More preferably, the density of the second aerosol generating substrate is at least twice the density of the first aerosol generating substrate. The density of the second aerosol generating substrate may be at most 4 times the density of the first aerosol generating substrate.

[0132] In a preferred embodiment of the invention, the density of the second aerosol-generating substrate is at least 1.2 times the density of the first aerosol-generating substrate and the aerosol-forming agent content of the second aerosol-generating substrate is at least twice the aerosol-forming agent content of the first aerosol-generating substrate.

[0133] The first aerosol-generating substrate and the second aerosol-generating substrate may be formed of substrates of the same type as each other. Suitable types of materials for use in the aerosol-generating articles of the present invention are described below, and include, for example, tobacco cut fillers, homogenized tobacco materials such as cast leaves, and aerosol-generating films. Preferably, the first aerosol-generating substrate and the second aerosol-generating substrate are different types of materials from each other.

[0134] Preferably, the first aerosol generating substrate comprises tobacco material. In certain preferred embodiments, the first aerosol generating substrate comprises shredded tobacco material. For example, as described in more detail below, shredded tobacco material can be in the form of shredded filler. Alternatively, shredded tobacco material can be in the form of shredded material of homogenized tobacco material. Suitable homogenized tobacco material for the present invention is described below.

[0135] In the context of this specification, the term "cut filler" is used to describe a blend of chopped plant material, such as tobacco plant material, particularly including one or more of leaves, processed stems and ribs, homogenised plant material.

[0136] Cut filler may also include other post-cut filler tobaccos or addenda.

[0137] Preferably, the shredded filler comprises at least 25% plant leaves, more preferably at least 50% plant leaves, still more preferably at least 75% plant leaves, and most preferably at least 90% plant leaves. Preferably, the plant material is one of tobacco, mint, tea and cloves. Most preferably, the plant material is tobacco. However, the present invention is equally applicable to other plant materials having the ability to release a substance and subsequently form an aerosol when heat is applied.

[0138] Preferably, the cut filler comprises tobacco plant material including thin layers of one or more of flue-cured tobacco, sun-cured tobacco, oriental tobacco and filler tobacco.With reference to the present invention, the term "tobacco" describes any plant member of the genus Nicotiana.

[0139] The shredded filler suitable for use with the present invention can be similar to the shredded filler for conventional smoking articles in general. The shredded width of the shredded filler is preferably between 0.3 mm and 2.0 mm, more preferably the shredded width of the shredded filler is between 0.5 mm and 1.2 mm, and most preferably the shredded width of the shredded filler is between 0.6 mm and 0.9 mm. The shredded width can work in the thermal distribution inside the first aerosol generating substrate. Equally, the shredded width can work in the suction resistance of the article. In addition, the shredded width can affect the total density of the aerosol generating substrate as a whole.

[0140] The strand length of the shredded filler is a random value to some extent, because the length of the strand will depend on the overall size of the object from which the strand is cut. However, by adjusting the material before cutting, for example by controlling the moisture content and overall fineness of the material, longer strands can be cut. Preferably, before arranging the strands to form the first aerosol generating substrate, the strands have a length between about 10 mm and about 40 mm. Obviously, if the strands are arranged in the first aerosol generating substrate with a longitudinal extension, wherein the longitudinal extension of the section is less than 40 mm, the first aerosol generating substrate may include strands that are shorter than the initial strand length on average. Preferably, the strand length of the shredded filler is such that the strands between about 20% and 60% extend along the full length of the first aerosol generating segment. This prevents the strands from easily falling off from the first aerosol generating segment.

[0141] In other preferred embodiments, the first aerosol-generating substrate comprises homogenised plant material, preferably homogenised tobacco material.

[0142] As used herein, the term "homogenized plant material" includes any plant material formed by the agglomeration of plant particles. For example, sheets or webs of homogenized tobacco material used for aerosol-generating substrates of the present invention can be formed by agglomerating particles of tobacco material, which are obtained by pulverizing, grinding or grinding plant material and one or more of optional tobacco leaves and tobacco stems. Homogenized plant material can be produced by casting, extruding, papermaking technology or other any suitable process known in the art.

[0143] The homogenised plant material may be provided in any suitable form.

[0144] In some embodiments, the homogenised plant material may be in the form of one or more sheets.As used herein with reference to the present invention, the term "sheet" describes a laminar element having a width and length substantially greater than its thickness.

[0145] As described above, the second aerosol-generating substrate may be in the form of cut filler or homogenised tobacco material.

[0146] Preferably, the second aerosol-generating substrate is in the form of an aerosol-generating film comprising a cellulose-based film-forming agent, nicotine and an aerosol-forming agent. The aerosol-generating film may further comprise a cellulose-based reinforcing agent. The aerosol-generating film may further comprise water, preferably 30 wt % or less of water.

[0147] As used herein, the term "film" is used to describe a solid laminar element whose thickness is less than its width or length. The film may be self-supporting. In other words, the film may have cohesive and mechanical properties such that the film may be separated from the supporting surface even if it is obtained by casting a film formulation on the supporting surface. Alternatively, the film may be disposed on a support or sandwiched between other materials. This may enhance the mechanical stability of the film.

[0148] The aerosol-forming agent content of the aerosol-generating film is within the range defined for the second aerosol-generating substrate.

[0149] In the context of the present invention, the term "cellulose-based film former" is used to describe a cellulosic polymer that is capable of forming a continuous film, either alone or in the presence of an auxiliary thickener.

[0150] Preferably, the cellulose-based film former is selected from hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), hydroxyethyl methylcellulose (HEMC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC) and combinations thereof.

[0151] More preferably, the cellulose-based film former is selected from hydroxypropylmethylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC) and combinations thereof.

[0152] In a particularly preferred embodiment, the cellulose-based film former is HPMC.

[0153] The aerosol-generating film used to form the second aerosol-generating substrate preferably comprises at least 10 wt% of a cellulose-based film-forming agent on a dry weight basis. More preferably, the aerosol-generating film comprises at least 15 wt% of a cellulose-based film-forming agent on a dry weight basis. More preferably, the aerosol-generating film comprises at least 20 wt% of a cellulose-based film-forming agent on a dry weight basis.

[0154] Preferably, the aerosol-forming film comprises no more than 40 wt% of a cellulose-based film-forming agent on a dry weight basis. More preferably, the aerosol-forming film comprises no more than 35 wt% of a cellulose-based film-forming agent on a dry weight basis. More preferably, the aerosol-forming film comprises no more than 30 wt% of a cellulose-based film-forming agent on a dry weight basis.

[0155] For example, the aerosol-generating film may have a cellulose-based film-forming agent content of between 10 wt% and 40 wt%, or between 15 wt% and 35 wt%, or between 20 wt% and 30 wt% on a dry weight basis.

[0156] Preferably, the aerosol-generating film further comprises a cellulose-based reinforcing agent.Preferably, the cellulose-based reinforcing agent is selected from the group consisting of cellulose fibers, microcrystalline cellulose (MCC), cellulose powder and combinations thereof.

[0157] The aerosol-generating film preferably comprises at least 0.5 wt% by dry weight of a cellulose-based reinforcing agent. More preferably, the aerosol-generating film comprises at least 5 wt% by dry weight of a cellulose-based reinforcing agent. More preferably, the aerosol-generating film comprises at least 10 wt% by dry weight of a cellulose-based reinforcing agent.

[0158] Preferably, the aerosol-generating film comprises no more than 40 wt% of a cellulose-based reinforcing agent on a dry weight basis. More preferably, the aerosol-generating film comprises no more than 30 wt% of a cellulose-based reinforcing agent on a dry weight basis. More preferably, the aerosol-generating film comprises no more than 25 wt% of a cellulose-based reinforcing agent on a dry weight basis.

[0159] For example, the aerosol-generating film may have a cellulose-based strengthening agent content of between 0.5 wt% and 40 wt% on a dry basis, or between 5 wt% and 30 wt% on a dry basis, or between 10 wt% and 25 wt% on a dry basis.

[0160] The aerosol-forming film may further comprise carboxymethylcellulose, preferably sodium carboxymethylcellulose.

[0161] The aerosol-generating film may have a carboxymethylcellulose content of greater than about 1 wt% on a dry weight basis. The aerosol-generating film may have a carboxymethylcellulose content of greater than about 2 wt% on a dry weight basis. The aerosol-generating film may have a carboxymethylcellulose content of greater than about 4 wt% on a dry weight basis.

[0162] The aerosol-generating film may have a carboxymethylcellulose content of less than about 15 wt % on a dry weight basis. The aerosol-generating film may have a carboxymethylcellulose content of less than about 12 wt % on a dry weight basis. The aerosol-generating film may have a carboxymethylcellulose content of less than about 10 wt % on a dry weight basis.

[0163] For example, the aerosol-generating film may have a carboxymethylcellulose content of between 1 wt% and 15 wt%, or between 2 wt% and 12 wt%, or between 4 wt% and 10 wt% on a dry weight basis.

[0164] The aerosol-generating film preferably comprises nicotine.

[0165] As used herein with respect to the present invention, the term "nicotine" is used to describe nicotine, nicotine base or nicotine salt. In embodiments where the aerosol-generating film comprises nicotine base or nicotine salt, the amount of nicotine recited herein is the amount of free base nicotine or the amount of protonated nicotine, respectively.

[0166] The aerosol-generating film may comprise natural nicotine or synthetic nicotine.

[0167] The aerosol-generating film may comprise one or more monobasic nicotine salts.

[0168] As used herein with respect to the present invention, the term "monobasic nicotine salt" is used to describe the nicotine salt of the monobasic acid.

[0169] Preferably, the aerosol-generating film comprises at least 0.5% by weight of nicotine on a dry weight basis. More preferably, the aerosol-generating film comprises at least 1% by weight of nicotine on a dry weight basis. Even more preferably, the aerosol-generating film comprises at least 2% by weight of nicotine on a dry weight basis. Additionally, or as an alternative, the aerosol-generating film preferably comprises less than 10% by weight of nicotine on a dry weight basis. More preferably, the aerosol-generating film comprises less than 8% by weight of nicotine on a dry weight basis. More preferably, the aerosol-generating film comprises less than 6% by weight of nicotine on a dry weight basis.

[0170] For example, the aerosol-generating film may comprise between 0.5 wt% and 10 wt% nicotine, or between 1 wt% and 8 wt% nicotine, or between 2 wt% and 6 wt% nicotine on a dry weight basis.

[0171] The aerosol-generating film may be a substantially tobacco-free aerosol-generating film.

[0172] In a preferred embodiment, the aerosol-forming film comprises an acid. More preferably, the aerosol-forming film comprises one or more organic acids. Even more preferably, the aerosol-forming film comprises one or more carboxylic acids. In particularly preferred embodiments, the acid is lactic acid, benzoic acid, fumaric acid or levulinic acid.

[0173] Preferably, the aerosol-forming film comprises at least about 0.25 wt % acid by dry weight. More preferably, the aerosol-forming film comprises at least about 0.5 wt % acid by dry weight. Even more preferably, the aerosol-forming film comprises at least about 1 wt % acid by dry weight. Additionally, or alternatively, the aerosol-forming film preferably comprises less than about 3.5 wt % acid by dry weight. More preferably, the aerosol-forming film comprises less than about 3 wt % acid by dry weight. Even more preferably, the aerosol-forming film comprises less than about 2.5 wt % acid by dry weight.

[0174] For example, the aerosol-generating film may comprise between 0.25 wt% and 3.5 wt% acid, or between 0.5 wt% and 3 wt% acid, or between 1 wt% and 2.5 wt% acid on a dry weight basis.

[0175] The aerosol-forming film may have a thickness of about 0.1 mm to about 1 mm, more preferably about 0.1 mm to about 0.75 mm, even more preferably about 0.1 mm to about 0.5 mm. In a particularly preferred embodiment, a layer of the film-forming composition having a thickness of about 50 microns to 400 microns, more preferably about 100 microns to 200 microns, is formed.

[0176] Alternatively, the aerosol-generating film may be provided on a suitable carrier element within the second aerosol-generating segment.

[0177] In an alternative embodiment of the invention, the second aerosol-generating substrate may comprise a gel composition comprising nicotine, at least one gelling agent and an aerosol former. The gel composition is preferably substantially free of tobacco.

[0178] Preferred weight ranges for nicotine in the gel composition are the same as those defined above for the aerosol-forming film.

[0179] The gel composition preferably comprises at least 50 wt% aerosol former, more preferably at least 60 wt% aerosol former, more preferably at least 70 wt% aerosol former, based on dry weight. The gel composition may comprise up to 80 wt% aerosol former. The aerosol former in the gel composition is preferably glycerol.

[0180] The gel composition preferably includes at least one gelling agent. Preferably, the gel composition includes a total amount of gelling agent in the range of about 0.4 wt % to about 10 wt %. More preferably, the composition includes a gelling agent in the range of about 0.5 wt % to about 8 wt %. More preferably, the composition includes a gelling agent in the range of about 1 wt % to about 6 wt %. More preferably, the composition includes a gelling agent in the range of about 2 wt % to about 4 wt %. More preferably, the composition includes a gelling agent in the range of about 2 wt % to about 3 wt %.

[0181] The term "gelling agent" refers to a compound that, when added to a mixture of 50 wt % water / 50 wt % glycerol in an amount of about 0.3 wt %, homogeneously forms a solid medium or support matrix that results in a gel. Gelling agents include, but are not limited to, hydrogen bond cross-linking gelling agents and ion cross-linking gelling agents.

[0182] The term "hydrogen-bonding cross-linking gelling agent" refers to a gelling agent that forms non-covalent cross-links or physical cross-links via hydrogen bonding. Hydrogen bonding is a type of electrostatic dipole-dipole attraction between molecules, rather than a covalent bond to a hydrogen atom. It is created by the attraction between a hydrogen atom covalently bonded to an extremely electronegative atom (such as an N, O, or F atom) and another extremely electronegative atom.

[0183] The hydrogen-bond cross-linking gelling agent may include one or more of galactomannan, gelatin, agarose or konjac gum or agar. The hydrogen-bond cross-linking gelling agent may preferably include agar.

[0184] The term "ionic crosslinking gelling agent" refers to a gelling agent that forms non-covalent crosslinks or physical crosslinks through ionic bonds. Ionic crosslinking involves the association of polymer chains through non-covalent interactions. A crosslinked network is formed when oppositely charged multivalent molecules are electrostatically attracted to each other to form a crosslinked polymer network.

[0185] The ionically cross-linked gelling agent may include low acyl gellan gum, pectin, kappa-carrageenan, iota-carrageenan or alginate. The ionically cross-linked gelling agent may preferably include low acyl gellan gum.

[0186] The gelling agent may include one or more biopolymers. The biopolymer may be formed from a polysaccharide.

[0187] Biopolymers include, for example, gellan gum (natural, low acyl gellan gum, high acyl gellan gum, preferably low acyl gellan gum), xanthan gum, alginates (alginic acid), agar, guar gum, etc. The composition may preferably include xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include substantially equal weights of two biopolymers. The composition may include substantially equal weights of three biopolymers.

[0188] The gel composition may also include a viscosity increasing agent. The viscosity increasing agent in combination with the hydrogen bonding cross-linking gelling agent and the ionic cross-linking gelling agent appears to unexpectedly support the solid medium and maintain the gel composition even when the gel composition includes high levels of glycerol.

[0189] The term "viscosity increasing agent" refers to a compound that, when homogenously added in an amount of 0.3 wt% to a mixture of 50 wt% water / 50 wt% glycerol at 25°C, increases viscosity without causing gel formation, the mixture remains or remains fluid. Preferably, the viscosity increasing agent refers to a compound that, when homogenously added in an amount of 0.3 wt% to a mixture of 50 wt% water / 50 wt% glycerol at 25°C, increases viscosity to at least 50 cPs, preferably at least 200 cPs, preferably at least 500 cPs, preferably at least 1000 cPs at a shear rate of 0.1 s-1, without causing gel formation, the mixture remains or remains fluid. Preferably, the viscosity increasing agent refers to a compound which, when homogeneously added in an amount of 0.3 wt % to a mixture of 50 wt % water / 50 wt % glycerol at 25° C., increases the viscosity at a shear rate of 0.1 s-1 by at least 2 times, or at least 5 times, or at least 10 times, or at least 100 times compared to before addition, without causing gel formation, and the mixture remains or remains fluid.

[0190] The viscosity values ​​described herein can be measured using a Brookfield RVT viscometer at 25°C with a rotating disk RV #2 spindle at 6 revolutions per minute (rpm).

[0191] The gel composition preferably includes a viscosity increasing agent in the range of about 0.2 wt % to about 5 wt %. Preferably, the composition includes a viscosity increasing agent in the range of about 0.5 wt % to about 3 wt %. Preferably, the composition includes a viscosity increasing agent in the range of about 0.5 wt % to about 2 wt %. Preferably, the composition includes a viscosity increasing agent in the range of about 1 wt % to about 2 wt %.

[0192] The thickener may include one or more of xanthan gum, carboxymethyl cellulose, microcrystalline cellulose, methyl cellulose, gum arabic, guar gum, lambda-carrageenan or starch. The thickener may preferably include xanthan gum.

[0193] The gel composition may also include divalent cations. Preferably, the divalent cations include calcium ions, such as calcium lactate in solution. For example, divalent cations such as calcium ions can help form a gel of a composition including a gelling agent such as an ionically cross-linked gelling agent. Ionic effects can help gel formation. The divalent cations can be present in the gel composition in a range of about 0.1% to about 1% by weight, or about 0.5% by weight.

[0194] The gel composition may also include an acid. The acid may include a carboxylic acid. The carboxylic acid may include a keto group. Preferably, the carboxylic acid may include a keto group having less than about 10 carbon atoms, or less than about 6 carbon atoms, or less than about 4 carbon atoms, such as levulinic acid or lactic acid. Preferably, the carboxylic acid has three carbon atoms (such as lactic acid).

[0195] The gel composition preferably includes some water. When the gel composition includes some water, the gel composition is more stable. Preferably, the gel composition includes at least about 1 wt %, or at least about 2 wt %, or at least about 5 wt % water. Preferably, the gel composition includes at least about 10 wt % or at least about 15 wt % water.

[0196] Preferably, the gel composition comprises between about 8% and 32% by weight of water. Preferably, the gel composition comprises about 15% to about 25% by weight of water. Preferably, the gel composition comprises about 18% to about 22% by weight of water. Preferably, the gel composition comprises about 20% by weight of water.

[0197] Preferably, when a gel composition is used, the second aerosol-generating substrate comprises a porous medium loaded with the gel composition. An advantage of a porous medium loaded with the gel composition is that the gel composition is retained within the porous medium, and this may aid in the manufacture, storage or transport of the gel composition. It may help maintain the desired shape of the gel composition, particularly during manufacture, transport or use.

[0198] The term "porous" is used herein to refer to a material that provides a plurality of pores or openings that allow air to pass through the material.

[0199] The porous medium can be any suitable porous material capable of holding or retaining the gel composition. Ideally, the porous medium allows the gel composition to move therein. In particular embodiments, the porous medium comprises a natural material, a synthetic or semi-synthetic material, or a combination thereof. In particular embodiments, the porous medium comprises a sheet material, a foam or a fiber, such as a loose fiber; or a combination thereof. In particular embodiments, the porous medium comprises a woven, non-woven or extruded material, or a combination thereof. Preferably, the porous medium comprises cotton, paper, viscose, PLA or cellulose acetate, or a combination thereof. Preferably, the porous medium comprises a sheet material, such as cotton or cellulose acetate. In a particularly preferred embodiment, the porous medium comprises a sheet made of cotton fibers.

[0200] The porous medium used in the present invention can be curled or shredded. In a preferred embodiment, the porous medium is curled. In an alternative embodiment, the porous medium includes shredded porous medium. The curling or shredding process can be before or after loading the gel composition.

[0201] In certain embodiments, the sheet material is a composite material. Preferably, the sheet material is porous. The sheet material can help manufacture tubular elements comprising gels. The sheet material can help introduce active agents into tubular elements comprising gels. The sheet material can help stabilize the structure of tubular elements comprising gels. The sheet material can assist in transporting or storing gels. Using the sheet material can enable or help add structure to a porous medium, for example by curling the sheet material.

[0202] The porous medium may be a thread. The thread may comprise, for example, cotton, paper or acetate. The thread may also be loaded with gel, as any other porous medium. The advantage of using a thread as a porous medium is that it may aid in ease of manufacturing.

[0203] The thread may be loaded with gel by any known means. The thread may simply be coated with gel, or the thread may be impregnated with gel. In manufacture, the thread may be impregnated with gel and stored ready for inclusion in the assembly of the tubular element.

[0204] The porous medium carrying the gel composition is preferably disposed within a tubular element that forms part of an aerosol-generating article. Ideally, the tubular element may be longer in longitudinal length than it is wide, but this is not essential, as it may be part of a multi-component article that ideally has a longer longitudinal length than it is wide. Typically, the tubular element is cylindrical, but this is not essential. For example, the tubular element may have an elliptical, polygonal, like a triangle or rectangle, or irregular cross-section.

[0205] The second aerosol-generating substrate may comprise an aerosol-generating film. The aerosol-generating film may comprise a cellulose-based film-forming agent, nicotine and glycerol. The aerosol-generating film may have a glycerol content of at least 40 wt%.

[0206] The first aerosol-generating substrate and the second aerosol-generating substrate include at least one aerosol-forming agent, and the aerosol-forming agent content of the second aerosol-generating substrate may be greater than the aerosol-forming agent content of the first aerosol-generating substrate.

[0207] Providing a lower aerosol-forming agent content in the first aerosol-generating substrate can advantageously provide improved aerosol delivery of an aerosol-generating article. The first aerosol-generating substrate with a lower level of aerosol-forming agent will heat up faster than if it has a higher aerosol-forming agent content due to its lower thermal inertia. This is advantageous because most of the first aerosol-generating substrate is not located in the heating zone and will therefore be heated to a lower temperature than the second aerosol-generating substrate. Although most of the aerosol-generating substrate will be subjected to indirect heating, providing a lower aerosol-forming agent content in the first aerosol-generating substrate can advantageously allow effective aerosol generation in the first aerosol-generating substrate. In contrast, because the second aerosol-generating substrate is heated more efficiently, the second aerosol-generating substrate that is primarily located in the heating zone can include a higher aerosol-forming agent content. The higher aerosol-forming agent content in the second aerosol-generating substrate can advantageously allow continuous aerosol delivery throughout the duration of using the aerosol-generating article.

[0208] Upon volatilization, the aerosol former may convey in the aerosol other volatile compounds such as nicotine and flavoring agents that are released from the aerosol-generating substrate upon heating.

[0209] Suitable aerosol formers for inclusion in the first aerosol-generating substrate and the second aerosol-generating substrate are known in the art and include, but are not limited to: polyols, such as triethylene glycol, propylene glycol, 1,3-butylene glycol and glycerol; esters of polyols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

[0210] The first aerosol-generating substrate and the second aerosol-generating substrate may comprise the same aerosol-forming agent (or agents) as each other, or different aerosol-forming agents may be used.

[0211] The first aerosol-generating substrate preferably has an aerosol-forming agent content of no more than 30 wt % on a dry weight basis. More preferably, the first aerosol-generating substrate has an aerosol-forming agent content of no more than 25 wt % on a dry weight basis. More preferably, the first aerosol-generating substrate has an aerosol-forming agent content of no more than 20 wt % on a dry weight basis.

[0212] Preferably, the first aerosol-generating substrate has an aerosol-forming agent content of at least 5 wt.-% on a dry weight basis. More preferably, the first aerosol-generating substrate has an aerosol-forming agent content of at least 10 wt.-% on a dry weight basis. More preferably, the first aerosol-generating substrate has an aerosol-forming agent content of at least 12 wt.-% on a dry weight basis. More preferably, the first aerosol-generating substrate has an aerosol-forming agent content of at least 15 wt.-% on a dry weight basis.

[0213] For example, the aerosol-forming agent content of the first aerosol-generating substrate may be between 5 wt % and 30 wt %, or between 10 wt % and 25 wt %, or between 12 wt % and 20 wt %, or between about 15 wt % and about 20 wt % on a dry weight basis.

[0214] Preferably, the first aerosol-generating substrate comprises glycerol as an aerosol-forming agent. For example, the first aerosol-generating substrate may contain between 5% and 30% glycerol by weight, or between 10% and 25% glycerol by weight, or between 12% and 20% glycerol by weight, or between 15% and 20% glycerol by weight on a dry weight basis.

[0215] The second aerosol-generating substrate preferably has a higher aerosol-forming agent content than the first aerosol-generating substrate.

[0216] Preferably, the second aerosol-generating substrate has an aerosol-forming agent content of at least 40 wt % on a dry weight basis. More preferably, the second aerosol-generating substrate has an aerosol-forming agent content of at least 45 wt % on a dry weight basis. More preferably, the second aerosol-generating substrate has an aerosol-forming agent content of at least 50 wt % on a dry weight basis.

[0217] Preferably, the second aerosol-generating substrate has an aerosol-forming agent content of no more than 80 wt % on a dry weight basis. More preferably, the second aerosol-generating substrate has an aerosol-forming agent content of no more than 75 wt % on a dry weight basis. More preferably, the second aerosol-generating substrate has an aerosol-forming agent content of no more than 70 wt % on a dry weight basis.

[0218] For example, the aerosol-forming agent content of the second aerosol-generating substrate may be between 40 wt% and 80 wt%, or between 45 wt% and 75 wt%, or between 50 wt% and 70 wt% on a dry weight basis.

[0219] Preferably, the second aerosol-generating substrate comprises glycerol as an aerosol-forming agent. For example, the second aerosol-generating substrate may comprise, by dry weight, between 40% and 80% glycerol, or between 45% and 75% glycerol, or between 50% and 70% glycerol, or between 15% and 20% glycerol.

[0220] Preferably, the second aerosol-generating substrate has an aerosol-forming agent content that is at least 15% higher than the aerosol-forming agent content of the first aerosol-generating substrate, based on dry weight. For example, if the first aerosol-generating substrate has an aerosol-forming agent content of 10% by dry weight, the second aerosol-generating substrate may have an aerosol-forming agent content of not less than 25% by dry weight.

[0221] More preferably, the aerosol-forming agent content of the second aerosol-generating substrate is at least 20% higher than the aerosol-forming agent content of the first aerosol-generating substrate, based on dry weight. More preferably, the aerosol-forming agent content of the second aerosol-generating substrate is at least 25% higher than the aerosol-forming agent content of the first aerosol-generating substrate, based on dry weight. The aerosol-forming agent content of the second aerosol-generating substrate may be up to 60% higher than the aerosol-forming agent content of the first aerosol-generating substrate.

[0222] Preferably, the aerosol-forming agent content of the second aerosol-generating substrate is at least 1.2 times the aerosol-forming agent content of the first aerosol-generating substrate, based on dry weight. More preferably, the aerosol-forming agent content of the second aerosol-generating substrate is at least 1.5 times the aerosol-forming agent content of the first aerosol-generating substrate, based on dry weight. More preferably, the aerosol-forming agent content of the second aerosol-generating substrate is at least twice the aerosol-forming agent content of the first aerosol-generating substrate, based on dry weight. The aerosol-forming agent content of the second aerosol-generating substrate may be up to 4 times the aerosol-forming agent content of the first aerosol-generating substrate.

[0223] In a preferred embodiment of the present invention, the density of the second aerosol generating substrate is at least 1.2 times the density of the first aerosol generating substrate, the aerosol former content of the second aerosol generating substrate is at least twice the aerosol former content of the first aerosol generating substrate on a dry weight basis, and the length ratio of the first aerosol generating segment to the second aerosol generating segment does not exceed 0.5.

[0224] The aerosol generating article may further include a third aerosol generating segment, which is downstream of the first aerosol generating segment and downstream of the second aerosol generating segment, and includes a third aerosol generating substrate. For example, the aerosol generating article may include a third aerosol generating segment adjacent to the downstream end of the second aerosol generating segment. Including the third aerosol generating segment downstream of the second aerosol generating segment can further enhance the aerosol delivery from the aerosol generating article according to the present invention. When the aerosol generating article is fully received in the heating chamber of the aerosol generating device, the full length of the third aerosol generating segment can be set within the heating zone. When the aerosol generating article is fully received in the heating chamber of the aerosol generating device, the third aerosol generating segment can be only partially set within the heating zone. When the aerosol generating article is fully received in the heating chamber of the aerosol generating device, the full length of the third aerosol generating segment can be set outside the heating zone.

[0225] The advantage of providing a third aerosol generating segment including a third aerosol generating substrate downstream of the first aerosol generating segment and the second aerosol generating segment is that it can allow the aerosol generating segment to be customized to deliver aerosols during earlier puffs using the aerosol generating system. For example, the third aerosol generating substrate can have a relatively low aerosol forming agent content or a relatively low density or both. For example, the third aerosol generating substrate preferably has an aerosol forming agent content and density within the range defined above for the first aerosol generating substrate. The teachings provided above about the first aerosol generating substrate are also applicable to the third aerosol generating substrate.

[0226] This may advantageously allow the third aerosol-generating substrate to heat up more quickly due to the lower thermal inertia and begin to generate a measurable amount of aerosol in a relatively short time. Since the third aerosol-generating segment is located downstream of both the first aerosol-generating segment and the second aerosol-generating segment, the aerosol generated by the third aerosol-generating substrate is efficiently delivered to the user with minimal self-filtration. This further improves aerosol delivery during earlier puffs using the aerosol-generating system.

[0227] The third aerosol generating segment may have any length. The third aerosol generating segment may have a length of at least 2 mm. For example, the third aerosol generating segment may have a length of at least 3 mm or at least 4 mm.

[0228] The third aerosol generating segment may have a length of no more than 8 mm. For example, the third aerosol generating segment may have a length of no more than 7 mm or no more than 6 mm.

[0229] The third aerosol generating segment may have a length of between 2 mm and 8 mm, between 3 mm and 7 mm, or between 4 mm and 6 mm.

[0230] The third aerosol generating segment may have a length of between 1 mm and 6 mm, between 2 mm and 5 mm, or between 3 mm and 4 mm.

[0231] The third aerosol generating segment may have a length of about 5 mm. The third aerosol generating segment may have a length of about 3.5 mm.

[0232] In some embodiments, the first aerosol generating segment, the second aerosol generating segment, and the third aerosol generating segment are arranged along the longitudinal axis of the aerosol generating article. The first aerosol generating segment can be arranged at the most upstream, and the third aerosol generating segment can be arranged at the most downstream. The second aerosol generating segment can be arranged between the first aerosol generating segment and the third aerosol generating segment. The downstream end of the first aerosol generating segment can be adjacent to the upstream end of the second aerosol generating segment. The downstream end of the second aerosol generating segment can be adjacent to the upstream end of the third aerosol generating segment.

[0233] The combined length of the first, second and third aerosol generating segments may be at least 10 mm. For example, the combined length of the first, second and third aerosol generating segments may be at least 12 mm, at least 14 mm or at least 16 mm.

[0234] The combined length of the first, second and third aerosol generating segments may not exceed 24 mm. For example, the combined length of the first, second and third aerosol generating segments may not exceed 22 mm, 20 mm or 18 mm.

[0235] The combined length of the first aerosol generating segment, the second aerosol generating segment and the third aerosol generating segment may be between 10 mm and 24 mm. For example, the combined length of the first aerosol generating segment, the second aerosol generating segment and the third aerosol generating segment may be between 12 mm and 22 mm, between 14 mm and 20 mm, or between 16 mm and 18 mm.

[0236] The combined length of the first aerosol generating segment, the second aerosol generating segment, and the third aerosol generating segment may be approximately 17 mm.

[0237] The aerosol-generating segment may have an outer diameter that is substantially equal to the outer diameter of the aerosol-generating article.

[0238] Preferably, the outer diameter of the aerosol generating segment is between 5 mm and 12 mm, more preferably between 6 mm and 10 mm, more preferably between 7 mm and 8 mm. In some embodiments, the outer diameter of the aerosol generating segment may be less than 7 mm, for example between 5 mm and 7 mm or between 6 mm and 7 mm.

[0239] The first aerosol-generating segment preferably has an outer diameter that is substantially equal to the outer diameter of the aerosol-generating article.Preferably, the outer diameter of the first aerosol-generating segment is substantially constant along the length of the first aerosol-generating segment.

[0240] Preferably, the outer diameter of the first aerosol generating segment is between 5 mm and 12 mm, more preferably between 6 mm and 10 mm, more preferably between 7 mm and 8 mm. In some embodiments, the outer diameter of the first aerosol generating segment may be less than 7 mm, for example between 5 mm and 7 mm or between 6 mm and 7 mm.

[0241] The second aerosol-generating segment preferably has an outer diameter that is substantially equal to the outer diameter of the aerosol-generating article.Preferably, the outer diameter of the second aerosol-generating segment is substantially constant along the length of the first aerosol-generating segment.

[0242] Preferably, the outer diameter of the second aerosol generating segment is between 5 mm and 12 mm, more preferably between 6 mm and 10 mm, more preferably between 7 mm and 8 mm. In some embodiments, the outer diameter of the second aerosol generating segment may be less than 7 mm, for example between 5 mm and 7 mm or between 6 mm and 7 mm.

[0243] The third aerosol-generating segment preferably has an outer diameter that is substantially equal to the outer diameter of the aerosol-generating article.Preferably, the outer diameter of the third aerosol-generating segment is substantially constant along the length of the third aerosol-generating segment.

[0244] Preferably, the outer diameter of the third aerosol generating segment is between 5 mm and 12 mm, more preferably between 6 mm and 10 mm, more preferably between 7 mm and 8 mm. In some embodiments, the outer diameter of the third aerosol generating segment may be less than 7 mm, for example between 5 mm and 7 mm or between 6 mm and 7 mm.

[0245] Preferably, the first aerosol-generating segment, the second aerosol-generating segment and the third aerosol-generating segment (where present) have substantially the same outer diameter as each other.

[0246] The average cross-sectional area of ​​the first aerosol generating segment is preferably at least 50% of the average cross-sectional area of ​​the aerosol generating article, more preferably at least 80% of the average cross-sectional area of ​​the aerosol generating article, more preferably at least 90% of the average cross-sectional area of ​​the aerosol generating article.

[0247] The cross-sectional area of ​​the first aerosol generating segment at its upstream end is preferably at least 50% of the average cross-sectional area of ​​the aerosol generating article, more preferably at least 80% of the average cross-sectional area of ​​the aerosol generating article, and more preferably at least 90% of the average cross-sectional area of ​​the aerosol generating article.

[0248] The average cross-sectional area of ​​the second aerosol generating segment is preferably at least 50% of the average cross-sectional area of ​​the aerosol generating article, more preferably at least 80% of the average cross-sectional area of ​​the aerosol generating article, more preferably at least 90% of the average cross-sectional area of ​​the aerosol generating article.

[0249] The cross-sectional area of ​​the second aerosol generating segment at its downstream end is preferably at least 50% of the average cross-sectional area of ​​the aerosol generating article, more preferably at least 80% of the average cross-sectional area of ​​the aerosol generating article, and more preferably at least 90% of the average cross-sectional area of ​​the aerosol generating article.

[0250] The cross-sectional area of ​​the first aerosol generating segment at its upstream end is substantially the same as the cross-sectional area of ​​the second aerosol generating segment at its downstream end.

[0251] The aerosol generating article of the present invention preferably includes an upstream element located upstream and near the first aerosol generating segment. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol generating segment. For example, where the aerosol generating substrate includes a sensor element, the upstream element may prevent direct physical contact with the upstream end of the sensor element. This helps prevent the sensor element from shifting or deforming during handling or transport of the aerosol generating article. This in turn helps to fix the form and position of the sensor element. In addition, the presence of the upstream element helps prevent any loss of the substrate, which may be advantageous, for example, if the substrate contains particulate plant material.

[0252] Where the first aerosol generating segment comprises shredded tobacco, such as tobacco cut filler, the upstream segment or elements thereof may additionally help prevent loose tobacco particles from being lost from the upstream end of the article. This may be particularly important, for example, when the shredded tobacco has a relatively low density.

[0253] The upstream section or an upstream element thereof may additionally provide a degree of protection for the aerosol-generating substrate during storage, as it covers, at least to some extent, the upstream end of the aerosol-generating substrate which might otherwise be exposed.

[0254] For aerosol-generating articles intended to be inserted into a heating chamber in an aerosol-generating device so that the aerosol-generating substrate can be externally heated within the heating chamber, the upstream segment or its upstream element may advantageously facilitate the insertion of the upstream end of the article into the heating chamber. The inclusion of the upstream element may also protect the end of the first aerosol-generating segment during insertion of the article into the heating chamber, minimizing the risk of damaging the substrate.

[0255] The upstream element may be a porous rod element. Preferably, the upstream element has a porosity of at least 50% in the longitudinal direction of the aerosol generating article. More preferably, the upstream element has a porosity of between 50% and 90% in the longitudinal direction. The porosity of the upstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of ​​the material forming the upstream element to the internal cross-sectional area of ​​the aerosol generating article at the location of the upstream element.

[0256] The upstream element may be made of a porous material or may include a plurality of openings. For example, this may be achieved by laser perforation. Preferably, the plurality of openings are evenly distributed over the cross section of the upstream element.

[0257] The porosity or permeability of the upstream element may advantageously be designed to provide a particular overall resistance to draw (RTD) to the aerosol-generating article without substantially affecting the filtration provided by other parts of the article.

[0258] The upstream element may be formed of a material that is impermeable to air.In such embodiments, the aerosol-generating article may be configured such that air flows into at least one of the first aerosol-generating segment and the second aerosol-generating segment through suitable ventilation means provided in the packaging.

[0259] In certain preferred embodiments of the present invention, it may be desirable to minimize the RTD of the upstream element. For example, as described herein, this may be the case for an article that is intended to be inserted into a heated chamber of an aerosol generating device such that the aerosol generating substrate is externally heated. For such articles, it is desirable to provide the article with as low an RTD as possible, such that the majority of the consumer's RTD experience is provided by the aerosol generating device rather than the article.

[0260] The overall RTD of the aerosol-generating article may be at least 10 mm H 2 O. For example, the overall RTD of the aerosol-generating article may be at least 20 mm H 2 O, at least 30 mm H 2 O, at least 35 mm H 2 O, or at least 40 mm H 2 O.

[0261] The overall RTD of the aerosol-generating article may be no more than 70 mm H 2 O. For example, the overall RTD of the aerosol-generating article may be no more than 60 mm H 2 O, no more than 55 mm H 2 O, no more than 50 mm H 2 O, or no more than 45 mm H 2 O.

[0262] The overall RTD of the aerosol generating article may be between 10 mm H2O and 70 mm H2O. For example, the overall RTD of the aerosol generating article may be between 20 mm H2O and 60 mm H2O, between 30 mm H2O and 55 mm H2O, between 35 mm H2O and 50 mm H2O, or between 40 mm H2O and 45 mm H2O.

[0263] The overall RTD of the aerosol-generating article may be between 40 mm H2O and 60 mm H2O, between 35 mm H2O and 40 mm H2O, between 45 mm H2O and 50 mm H2O, or between 55 mm H2O and 65 mm H2O.

[0264] The overall RTD of the aerosol-generating article may be about 38 mm H2O, about 48 mm H2O, or about 60 mm H2O.

[0265] The aerosol generating article according to the present invention preferably also includes a downstream section, which is located downstream of the first aerosol generating segment, the second aerosol generating segment and the third aerosol generating segment (where present). The downstream section is preferably located immediately downstream of the second aerosol generating segment or the third aerosol generating segment (where present). The downstream section of the aerosol generating article preferably extends between the second aerosol generating segment or the third aerosol generating segment (where present) and the downstream end of the aerosol generating article. The downstream section may include one or more elements, each of which will be described in more detail within the present disclosure.

[0266] The length of the downstream section may be at least 20 mm. The length of the downstream section may be at least 25 mm. The length of the downstream section may be at least 30 mm.

[0267] The length of the downstream section may be less than 70 mm. The length of the downstream section may be equal to or less than 60 mm. The length of the downstream section may be equal to or less than 50 mm.

[0268] For example, the length of the downstream section may be between 20 mm and 70 mm, or between 25 mm and 60 mm, or between 30 mm and 50 mm.

[0269] Providing a relatively long downstream section ensures that a suitable length of the aerosol-generating article protrudes from the aerosol-generating device when the article is received in the aerosol-generating device. Such a suitable protruding length facilitates easy insertion and extraction of the article from the device, which also ensures that the upstream part of the article (particularly during insertion) is properly inserted into the device with a reduced risk of damage.

[0270] The ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be less than 0.80. More preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be less than 0.75. Even more preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be less than 0.70.

[0271] The ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be at least 0.30. Preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be at least 0.40. More preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be at least 0.50.

[0272] In some embodiments, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article is from 0.30 to 0.80, preferably from 0.40 to 0.75, more preferably from 0.50 to 0.70.

[0273] The downstream section of an aerosol-generating article according to the invention preferably comprises a hollow tubular cooling element disposed downstream of the second aerosol-generating segment or the third aerosol-generating segment where present. The hollow tubular cooling element may advantageously provide an aerosol-cooling element for the aerosol-generating article.

[0274] The hollow tubular cooling element may be disposed immediately downstream of the second aerosol generating segment or the third aerosol generating segment (where present). In other words, the hollow tubular cooling element may be adjacent to the downstream end of the second aerosol generating segment or the downstream end of the third aerosol generating segment (where present). The hollow tubular cooling element may define the upstream end of the downstream section of the aerosol generating article. The downstream end of the aerosol generating article may coincide with the downstream end of the downstream section. In some embodiments, the downstream section of the aerosol generating article comprises a single hollow tubular element. In other words, the downstream section of the aerosol generating article may include only one hollow tubular element. In other embodiments, as described below, the downstream section comprises two or more hollow tubular elements.

[0275] As used throughout this disclosure, the term "hollow tubular element" refers to a generally elongated element that defines a lumen or airflow passage along its longitudinal axis. In particular, the term "tubular" will hereinafter be used to refer to a tubular element having a substantially cylindrical cross-section and defining at least one airflow conduit that establishes uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it should be understood that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular element may be possible.

[0276] In the context of the present invention, the hollow tubular cooling element provides an unrestricted flow channel. This means that the hollow tubular cooling element provides a negligible resistance to draw (RTD) level. The term "negligible RTD level" is used to describe a hollow tubular cooling element having an RTD of less than 1 mm H2O / 10 mm length, preferably less than 0.4 mm H2O / 10 mm length of the hollow tubular cooling element, and more preferably less than 0.1 mm H2O / 10 mm length of the hollow tubular cooling element.

[0277] The RTD of the hollow tubular cooling element is preferably less than or equal to 10 mm H2O. More preferably, the RTD of the hollow tubular cooling element is less than or equal to 5 mm H2O. Even more preferably, the RTD of the hollow tubular cooling element is less than or equal to 2.5 mm H2O. Even more preferably, the RTD of the hollow tubular cooling element is less than or equal to 2 mm H2O. Even more preferably, the RTD of the hollow tubular cooling element is less than or equal to 1 mm H2O.

[0278] The RTD of the hollow tubular cooling element may be at least 0 mm H2O, or at least 0.25 mm H2O, or at least 0.5 mm H2O, or at least 1 mm H2O.

[0279] In an aerosol-generating article according to the invention, the overall RTD of the article essentially depends on the RTD of the aerosol-generating segment and optionally on the RTD of downstream and / or upstream elements. This is because the hollow tubular cooling element is essentially empty and thus substantially only minimally affects the overall RTD of the aerosol-generating article.

[0280] Therefore, the flow channel should be free of any components that would hinder the flow of air in the longitudinal direction.Preferably, the flow channel is substantially empty, and particularly preferably the flow channel is empty.

[0281] As will be described in more detail within the present disclosure, the aerosol-generating article may include a ventilation zone at a location along the downstream segment. In some embodiments, the aerosol-generating article may include a ventilation zone at a location along the hollow tubular cooling element. This ventilation zone or any ventilation zone may extend through the peripheral wall of the hollow tubular cooling element. Thus, fluid communication is established between the flow channel defined by the interior of the hollow tubular cooling element and the external environment. Ventilation zones are further described within the present disclosure.

[0282] Preferably, the length of the hollow tubular cooling element is at least 15 mm. More preferably, the length of the hollow tubular cooling element is at least 20 mm. The length of the hollow tubular cooling element may be at least 25 mm. More preferably, the length of the hollow tubular cooling element is at least 30 mm.

[0283] Preferably, the length of the hollow tubular cooling element is less than 50 mm. More preferably, the length of the hollow tubular cooling element is less than 45 mm. More preferably, the length of the hollow tubular cooling element is less than 40 mm.

[0284] The relatively long hollow tubular cooling element provides and defines a relatively long internal cavity within the aerosol generating article and downstream of the second aerosol generating segment or the third aerosol generating segment (if present). As discussed in the present disclosure, providing a cavity downstream (preferably, immediately downstream) of the aerosol generating substrate enhances nucleation of aerosol particles generated by the substrate. Providing a relatively long cavity maximizes such nucleation benefits, thereby improving aerosol formation and cooling.

[0285] The thickness of the peripheral wall of the hollow tubular cooling element (in other words, the wall thickness) may be at least 100 micrometers. The wall thickness of the hollow tubular cooling element may be at least 150 micrometers. The wall thickness of the hollow tubular cooling element may be at least 200 micrometers, preferably at least 250 micrometers, and even more preferably at least 500 micrometers (or 0.5 millimeters).

[0286] The wall thickness of the hollow tubular cooling element may be less than or equal to 2 mm, preferably less than or equal to 1.5 mm, and even more preferably less than or equal to 1.25 mm. The wall thickness of the hollow tubular cooling element may be less than or equal to 1 mm. The wall thickness of the hollow tubular cooling element may be less than or equal to 500 microns.

[0287] The wall thickness of the hollow tubular cooling element may be between 100 micrometers and 2 millimeters, preferably between 150 micrometers and 1.5 millimeters, even more preferably between 200 micrometers and 1.25 millimeters.

[0288] Preferably, the wall thickness of the hollow tubular cooling element is 250 microns (0.25 mm).

[0289] At the same time, keeping the thickness of the peripheral wall of the hollow tubular cooling element relatively low ensures that the total internal volume of the hollow tubular cooling element (which allows the aerosol to begin the nucleation process once the aerosol components leave the aerosol generating segment) and the cross-sectional surface area of ​​the hollow tubular cooling element is effectively maximized, while ensuring that the hollow tubular cooling element has the necessary structural strength to prevent collapse of the aerosol generating article and provide some support for the aerosol generating segment, and the RTD of the hollow tubular cooling element is minimized. Larger values ​​of the cross-sectional surface area of ​​the cavity of the hollow tubular cooling element should be understood to be associated with a reduced velocity of the aerosol flow traveling along the aerosol generating article, which is also expected to be beneficial to aerosol nucleation. In addition, it appears that by utilizing a hollow tubular cooling element with a relatively low thickness, ventilation air diffusion can be substantially prevented before the ventilation air contacts and mixes with the aerosol flow, which is also understood to be further beneficial to the nucleation phenomenon. In practice, the effect of cooling on the formation of new aerosol particles can be enhanced by providing more controlled local cooling of the volatile substance flow.

[0290] The hollow tubular cooling element preferably has an outer diameter that is substantially equal to the outer diameter of the aerosol-generating segment and the outer diameter of the aerosol-generating article.

[0291] The hollow tubular cooling element may have an inner diameter. Preferably, the hollow tubular cooling element may have a constant inner diameter along the length of the hollow tubular cooling element. However, the inner diameter of the hollow tubular cooling element may vary along the length of the hollow tubular cooling element.

[0292] The hollow tubular cooling element may have an inner diameter of at least 2 mm. For example, the hollow tubular cooling element may have an inner diameter of at least 3 mm, at least 4 mm, or at least 5 mm.

[0293] Providing a hollow tubular cooling element having an inner diameter as described above may advantageously provide the hollow tubular cooling element with sufficient rigidity and strength.

[0294] The hollow tubular cooling element may have an inner diameter of no more than 10 mm. For example, the hollow tubular cooling element may have an inner diameter of no more than 9 mm, no more than 8 mm, or no more than 7 mm.

[0295] Providing a hollow tubular cooling element having an inner diameter as described above may advantageously reduce the pumping resistance of the hollow tubular cooling element.

[0296] The hollow tubular cooling element may have an inner diameter of between 2 mm and 10 mm, between 3 mm and 9 mm, between 4 mm and 8 mm, or between 5 mm and 7 mm.

[0297] The hollow tubular cooling element may comprise a paper based material. The hollow tubular cooling element may comprise at least one paper layer. The paper may be a very stiff paper. The paper may be a curled paper, such as a curled heat resistant paper or a curled parchment paper.

[0298] Preferably, the hollow tubular cooling element may comprise cardboard. The hollow tubular cooling element may be a cardboard tube. The hollow tubular cooling element may be formed from cardboard.

[0299] The hollow tubular cooling element may include a polymeric material. For example, the hollow tubular cooling element may include a polymer film. The polymer film may include a cellulose film. The hollow tubular cooling element may include low density polyethylene (HDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube may include cellulose acetate tow.

[0300] In some embodiments, aerosol-generating articles according to the invention may comprise a ventilation zone at a position along the downstream segment. In more detail, in those embodiments in which the downstream segment comprises a hollow tubular cooling element, the ventilation zone may be provided at a position along the hollow tubular cooling element. Alternatively, in those embodiments in which the downstream segment comprises a downstream hollow tubular element, as described below, the ventilation zone may be provided at a position along the downstream hollow tubular element.

[0301] Thus, the ventilation cavity is arranged downstream of the aerosol generating segment.This provides several potential technical benefits.

[0302] Firstly, the inventors have found that one such ventilated hollow tubular cooling element provides particularly effective aerosol cooling. Thus, satisfactory aerosol cooling can be achieved even with relatively short downstream sections.

[0303] Secondly, the inventors have surprisingly found that this rapid cooling of the volatile substances released upon heating the aerosol-generating substrate promotes enhanced nucleation of aerosol particles.

[0304] The ventilation zone may typically comprise a plurality of perforations through the peripheral wall of the hollow tubular cooling element. Preferably, the ventilation zone comprises at least one row of circumferential perforations. In some embodiments, the ventilation zone may comprise two rows of circumferential perforations. For example, the perforations may be formed on a production line during manufacture of the aerosol-generating article. Preferably, each row of circumferential perforations comprises 8 to 30 perforations.

[0305] Aerosol-generating articles according to the invention may have a ventilation level of at least 25%.

[0306] Throughout this specification, the term "ventilation level" is used to denote the volume ratio between the airflow entering the aerosol-generating article via the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the higher the dilution of the aerosol flow delivered to the consumer. The aerosol-generating article preferably has a ventilation level of at least 25%, more preferably at least 30%, even more preferably at least 40%, even more preferably at least 50%.

[0307] Aerosol-generating articles according to the invention may have a ventilation level of up to 90%. Preferably, the ventilation level of an aerosol-generating article according to the invention is less than or equal to 80%, more preferably less than or equal to 70%, even more preferably less than or equal to 60%.

[0308] Without wishing to be bound by theory, the inventors have discovered that the temperature drop caused by cooler outside air entering the hollow tubular cooling element via the ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

[0309] As discussed in the present disclosure, the downstream segment may include a downstream filter segment. The downstream filter segment may extend to a downstream end of the downstream segment. The downstream filter segment may be located at the downstream end of the aerosol-generating article. The downstream end of the downstream filter segment may define the downstream end of the aerosol-generating article.

[0310] The downstream filter segment may be located downstream of the hollow tubular cooling element as described above.The downstream filter segment may extend between the hollow tubular cooling element and the downstream end of the aerosol-generating article.

[0311] The downstream filter segment is preferably a solid rod, which may also be described as a "plain" rod and is non-tubular. Thus, the filter segment preferably has a substantially uniform cross-section.

[0312] The downstream filter segment is preferably formed of a fibrous filter material. The fibrous filter material can be used to filter the aerosol generated by the aerosol generating substrate. Suitable fibrous filter materials will be known to the skilled person. Particularly preferably, at least one downstream filter segment comprises a cellulose acetate filter segment formed of cellulose acetate tow.

[0313] In certain preferred embodiments, the downstream section comprises a single downstream filter segment.In alternative embodiments, the downstream section comprises two or more downstream filter segments axially aligned in end-to-end abutting relationship with each other.

[0314] The downstream filter segment may optionally include a flavoring agent, which may be provided in any suitable form. For example, the downstream filter segment may include one or more capsules, beads or particles of a flavoring agent, or one or more threads or wires loaded with a flavoring agent.

[0315] Preferably, the downstream filter segment has a low particle filtration efficiency.

[0316] Preferably, the downstream filter segment is defined by the stick wrap.Preferably, the downstream filter segment is not ventilated, such that air does not enter the aerosol-generating article along the downstream filter segment.

[0317] The downstream filter segment is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article by means of a tipping wrapper.

[0318] The downstream filter segment preferably has an outer diameter substantially equal to the outer diameter of the aerosol-generating article.The diameter of the downstream filter segment may be substantially the same as the outer diameter of the hollow tubular cooling element.

[0319] The outer diameter of the downstream filter segment may be between 5 mm and 12 mm. The diameter of the downstream filter segment may be between 6 mm and 10 mm, between 7 mm and 8 mm. In certain embodiments, the diameter of the downstream filter segment may be less than 7 mm, for example, between 5 mm and 7 mm or between 6 mm and 7 mm.

[0320] Unless otherwise stated, the resistance to draw (RTD) of a component or aerosol generating article is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the full length of a component. The term "pressure drop" or "draw resistance" of a component or article may also refer to "resistance to draw". Such terms generally refer to measurements in accordance with ISO 6565-2015, which are generally made in tests at a temperature of 22 degrees Celsius, a pressure of 101 kPa (about 760 Torr) and a relative humidity of 60%, at a volume flow rate of 17.5 ml / sec at the output or downstream end of the measuring component. Conditions for smoking and smoking machine specifications are set forth in ISO Standard 3308 (ISO 3308:2000). The atmosphere for conditioning and testing is set forth in ISO Standard 3402 (ISO 3402:1999).

[0321] The resistance to draw (RTD) of the downstream section may be at least 0 mm H2O. The RTD of the downstream section may be at least 3 mm H2O. The RTD of the downstream section may be at least 6 mm H2O.

[0322] The RTD of the downstream section may be no greater than 12 mm H2O. The RTD of the downstream section may be no greater than 11 mm H2O. The RTD of the downstream section may be no greater than 10 mm H2O.

[0323] The length of the downstream filter segment may be at least 5 mm. The length of the downstream filter segment may be at least 10 mm. The length of the downstream filter segment may be less than 25 mm. The length of the downstream filter segment may be less than 20 mm. For example, the length of the downstream filter segment may be between 5 mm and 25 mm, or between 10 mm and 25 mm, or between 5 mm and 20 mm, or between 10 mm and 20 mm.

[0324] The downstream section may also include one or more additional hollow tubular elements.

[0325] In certain embodiments, the downstream section may include a hollow tubular support element upstream of the hollow tubular cooling element described above. Preferably, the hollow tubular support element is adjacent to the downstream end of the second aerosol generating segment or the third aerosol generating segment (where present). Preferably, the hollow tubular support element is adjacent to the upstream end of the hollow tubular cooling element. Preferably, the hollow tubular support element and the hollow tubular cooling element are adjacent to each other and together provide a hollow tubular section within the downstream section.

[0326] Alternatively or in addition to the hollow tubular support element, the downstream section may also include a downstream hollow tubular element downstream of the hollow tubular cooling element. The downstream hollow tubular element may be arranged in close proximity to the hollow tubular cooling element. In the case where the downstream section also includes an additional downstream hollow tubular element, as described above, the additional downstream hollow tubular element may be formed of the same material or a different material than the downstream hollow tubular element.

[0327] In certain preferred embodiments, the downstream section may include a ventilation zone at a location on the downstream hollow tubular element. In one example, this ventilation zone at a location on the downstream hollow tubular element may be provided instead of a ventilation zone at a location on the hollow tubular cooling element. In another example, a ventilation zone at a location on the downstream hollow tubular element may be provided in addition to the ventilation zone provided at a location on the hollow tubular cooling element.

[0328] The ventilation zone at a location along the downstream hollow tubular element may include a plurality of perforations through the peripheral wall of the downstream hollow tubular element. Preferably, the ventilation zone at a location along the downstream hollow tubular element includes at least one row of circumferential perforations. In some embodiments, the ventilation zone may include two rows of circumferential perforations. For example, the perforations may be formed on a production line during manufacture of the aerosol-generating article. Preferably, each row of circumferential perforations includes 8 to 30 perforations.

[0329] The downstream section may optionally further include an additional cooling element that defines a plurality of longitudinally extending channels so that a large surface area is available for heat exchange. In other words, one such additional cooling element is suitable for acting essentially as a heat exchanger. A plurality of longitudinally extending channels may be defined by a sheet material that has been pleated, gathered or folded to form a channel. A plurality of longitudinally extending channels may be defined by a single sheet that has been pleated, gathered and folded to form a plurality of channels. The sheet may have been curled before pleating, gathering or folding. Alternatively, a plurality of longitudinally extending channels may be defined by a plurality of sheets that have been curled, pleated, gathered and folded to form a plurality of channels. In some embodiments, a plurality of longitudinally extending channels may be defined by a plurality of sheets that have been curled, pleated, gathered or folded together, i.e., defined by two or more sheets that have entered an overlying arrangement and then curled, pleated, gathered or folded into one.

[0330] As used herein, the term "curled" means that the sheet has a plurality of substantially parallel ridges or folds. Preferably, when the aerosol-generating article is assembled, the substantially parallel ridges or folds extend in the longitudinal direction. As used herein, the terms "gathered", "pleated" or "folded" mean that the sheet of material is rolled, folded or otherwise compressed or contracted substantially transversely to the cylindrical axis of the aerosol-generating article. The sheet may be curled before being gathered, pleated or folded. The sheet may be gathered, pleated or folded without prior curling.

[0331] One such additional cooling element may have a total surface area of ​​between about 300 square millimeters per millimeter of length and about 1000 square millimeters per millimeter of length.

[0332] The additional cooling element preferably provides low resistance to air passing through the additional cooling element. Preferably, the additional cooling element does not substantially affect the resistance to draw of the aerosol-generating article. In order to achieve this, it is preferred that the porosity in the longitudinal direction is greater than 50% and the airflow path through the additional cooling element is relatively unconstrained. The longitudinal porosity of the additional cooling element may be defined by the ratio of the cross-sectional area of ​​the material forming the additional cooling element to the internal cross-sectional area of ​​the aerosol-generating article at the portion containing the additional cooling element.

[0333] The additional cooling element preferably comprises a sheet material selected from metal foil, polymer sheet and substantially non-porous paper or paperboard. In some embodiments, the aerosol-cooling element may comprise a sheet material selected from the group consisting of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose acetate (CA) and aluminum foil. In a particularly preferred embodiment, the additional cooling element comprises a sheet of PLA.

[0334] Preferably, the overall length of an aerosol-generating article according to the present invention is at least 40 mm. More preferably, the overall length of an aerosol-generating article according to the present invention is at least 50 mm. Even more preferably, the overall length of an aerosol-generating article according to the present invention is at least 60 mm.

[0335] The overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 90 mm. More preferably, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 85 mm. Even more preferably, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 80 mm.

[0336] In some embodiments, the overall length of the aerosol-generating article is preferably 40 mm to 70 mm, more preferably 45 mm to 70 mm. In other embodiments, the overall length of the aerosol-generating article is preferably 40 mm to 60 mm, more preferably about 45 mm to about 60 mm. In further embodiments, the overall length of the aerosol-generating article is preferably 40 mm to 50 mm, more preferably 45 mm to 50 mm. In an exemplary embodiment, the overall length of the aerosol-generating article is about 45 mm.

[0337] In alternative embodiments, the overall length of the aerosol-generating article is preferably 50 mm to 90 mm, more preferably 60 mm to 90 mm, and even more preferably 70 mm to 90 mm. In other embodiments, the overall length of the aerosol-generating article is preferably 50 mm to 85 mm, more preferably 60 mm to 85 mm, and even more preferably 70 mm to 85 mm. In further embodiments, the overall length of the aerosol-generating article is preferably 50 mm to 80 mm, more preferably 60 mm to 80 mm, and even more preferably 70 mm to 80 mm. In an exemplary embodiment, the overall length of the aerosol-generating article is 75 mm.

[0338] The aerosol-generating article has an outer diameter of at least 5 mm. Preferably, the aerosol-generating article has an outer diameter of at least 6 mm. More preferably, the aerosol-generating article has an outer diameter of at least 7 mm.

[0339] Preferably, the aerosol-generating article has an outer diameter of less than or equal to about 12 mm. More preferably, the aerosol-generating article has an outer diameter of less than or equal to about 10 mm. Even more preferably, the aerosol-generating article has an outer diameter of less than or equal to about 8 mm.

[0340] In some embodiments, the aerosol generating article has an outer diameter of about 5 mm to about 12 mm, preferably about 6 mm to about 12 mm, and more preferably about 7 mm to about 12 mm. In other embodiments, the aerosol generating article has an outer diameter of about 5 mm to about 10 mm, preferably about 6 mm to about 10 mm, and more preferably about 7 mm to about 10 mm. In other embodiments, the aerosol generating article has an outer diameter from about 5 mm to about 8 mm, preferably from about 6 mm to about 8 mm, and more preferably from about 7 mm to about 8 mm. In other embodiments, the aerosol generating article has an outer diameter of less than 7 mm.

[0341] The outer diameter of the aerosol-generating article may be substantially constant over the entire length of the article. Alternatively, different parts of the aerosol-generating article may have different outer diameters.

[0342] In particularly preferred embodiments, one or more of the components of the aerosol-generating article is individually defined by its own wrapper.

[0343] In an embodiment, the first aerosol generating segment, the second aerosol generating segment and the mouthpiece element are wrapped separately. The upstream element (where present), the first aerosol generating segment, the second aerosol generating segment and the hollow tubular element are then combined with an outer wrapper. Subsequently, they are combined with a downstream filter element having its own wrapper by means of tipping paper.

[0344] Preferably, at least one component of the aerosol-generating article is packaged in a hydrophobic wrapper.

[0345] The term "hydrophobic" refers to a surface that exhibits water repellent properties. A useful method for determining this is to measure the water contact angle. The "water contact angle" is the angle conventionally measured across a liquid when a liquid / vapor interface encounters a solid surface. It quantifies the wettability of a solid surface by a liquid via Young's equation. Hydrophobicity or water contact angle can be determined by utilizing the TAPPI T558 test method, and the results are presented as the interfacial contact angle and are reported in "degrees," and can range from near zero to near 180 degrees.

[0346] In a preferred embodiment, the hydrophobic wrapper is a wrapper comprising a paper layer having a water contact angle of about 30 degrees or greater, and preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

[0347] For example, the paper layer may include PVOH (polyvinyl alcohol) or silicon. PVOH may be applied to the paper layer as a surface coating, or the paper layer may include a surface treatment including PVOH or silicon.

[0348] In certain embodiments of the present invention, the aerosol-generating article further comprises one or more elongated susceptor elements within one or both of the first aerosol-generating segment and the second aerosol-generating segment. For example, the one or more elongated susceptor elements may be substantially longitudinally arranged within one or both of the first aerosol-generating segment and in thermal contact with one or both of the first aerosol-generating substrate and the second aerosol-generating substrate.

[0349] As used herein with reference to the present invention, the term "susceptor element" refers to a material that is capable of converting electromagnetic energy into heat. When located within a fluctuating electromagnetic field, eddy currents induced in the susceptor element result in heating of the susceptor element. As the susceptor element is positioned in thermal contact with the aerosol-generating substrate, the aerosol-generating substrate is heated by the susceptor element.

[0350] The term "elongated" when used to describe a susceptor element means that the length dimension of the susceptor element is greater than its width dimension or its thickness dimension, such as greater than twice its width dimension or its thickness dimension.

[0351] The susceptor element is arranged substantially longitudinally within at least one of the first aerosol generating segment and the second aerosol generating segment. This means that the length dimension of the elongated susceptor element is arranged to be substantially parallel to the longitudinal direction of at least one of the first aerosol generating segment and the second aerosol generating segment, for example within plus or minus 10 degrees parallel to the longitudinal direction of at least one of the first aerosol generating segment and the second aerosol generating segment. In a preferred embodiment, the elongated susceptor element may be positioned in a radially central position within at least one of the first aerosol generating segment and the second aerosol generating segment and extends along the longitudinal axis of at least one of the first aerosol generating segment and the second aerosol generating segment.

[0352] Preferably, the susceptor element extends all the way to the downstream end of at least one of the first aerosol generating segment and the second aerosol generating segment. In some embodiments, the susceptor element may extend all the way to the upstream end of at least one of the first aerosol generating segment and the second aerosol generating segment. In particularly preferred embodiments, the susceptor element has substantially the same length as the aerosol generating segment in which it is included, and extends from the upstream end of the segment to the downstream end of the segment.

[0353] The susceptor element is preferably in the form of a pin, a bar, a strip or a blade.

[0354] The susceptor element preferably has a length of 10 mm to 40 mm, for example 15 mm to 35 mm or 17 mm to 30 mm.

[0355] The susceptor element preferably has a length of 5 mm to 15 mm, for example 6 mm to 12 mm or 8 mm to 10 mm.

[0356] The susceptor element preferably has a width of 1 mm to 5 mm.

[0357] The thickness of the susceptor element is typically 0.01 mm to 2 mm, such as 0.5 mm to 2 mm. In some embodiments, the susceptor element preferably has a thickness of 10 microns to 500 microns, more preferably 10 microns to 100 microns.

[0358] Preferably, the length of the elongate susceptor element is equal to or shorter than the length of the aerosol generating segment in which the elongate susceptor element is contained.Preferably, the elongate susceptor element has the same length as the aerosol generating segment in which the elongate susceptor element is contained.

[0359] The susceptor element may be formed from any material that is capable of being inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate.Preferably the susceptor element comprises metal or carbon.

[0360] Preferred susceptor elements may include or consist of ferromagnetic materials, such as ferromagnetic alloys, ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptor elements may be or include aluminum. Preferred susceptor elements may be formed of 400 series stainless steel, such as 410 grade or 420 grade or 430 grade stainless steel. Different materials will dissipate different amounts of energy when positioned within an electromagnetic field having similar frequency and field strength values.

[0361] Thus, parameters of the susceptor element such as material type, length, width and thickness can all be altered to achieve the desired power dissipation within a known electromagnetic field.Preferred susceptor elements can be heated to temperatures in excess of 250 degrees Celsius.

[0362] Suitable susceptor elements may include a non-metallic core having a metal layer disposed on the non-metallic core, such as metal tracks formed on the surface of a ceramic core. The susceptor element may have an outer protective layer, such as a ceramic protective layer or a glass protective layer encapsulating the susceptor element. The susceptor element may include a protective coating formed of glass, ceramic or an inert metal formed on the core of the susceptor element material.

[0363] The susceptor element is arranged in thermal contact with the aerosol-generating substrate of the aerosol-generating segment in which the susceptor element is contained. Thus, when the susceptor element heats up, the aerosol-generating substrate heats up and forms an aerosol. Preferably, the susceptor element is arranged in direct physical contact with the aerosol-generating substrate, for example within the aerosol-generating substrate.

[0364] The first aerosol-generating substrate may be defined by a first wrapper.The second aerosol-generating substrate may be defined by a second wrapper separate from the first wrapper.Thus, each aerosol-generating segment has its own distinct stick wrapper surrounding the respective aerosol-generating substrate.

[0365] The first aerosol-generating segment and the second aerosol-generating segment may be defined by a further wrapper which may combine the aerosol-generating segments and hold them in position relative to each other.

[0366] The wrapper defining the first aerosol generating substrate, the second aerosol generating substrate or the first aerosol generating segment and the second aerosol generating segment may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in particular embodiments of the invention are known in the art and include, but are not limited to: cigarette papers; and filter tip segment wrappers. Suitable non-paper wrappers for use in particular embodiments of the invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material.

[0367] The paper wrapper may have a grammage of at least 15gsm (grams per square meter), preferably at least 20gsm. The paper wrapper may have a grammage of less than or equal to 35gsm, preferably less than or equal to 30gsm. The paper wrapper may have a grammage of 15gsm to 35gsm, preferably 20gsm to 30gsm. In a preferred embodiment, the paper wrapper may have a grammage of 25gsm. The paper wrapper may have a thickness of at least 25 microns, preferably at least 30 microns, more preferably at least 35 microns. The paper wrapper may have a thickness of less than or equal to 55 microns, preferably less than or equal to 50 microns, more preferably less than or equal to 45 microns. The paper wrapper may have a thickness of 25 microns to 55 microns, preferably 30 microns to 50 microns, more preferably 35 microns to 45 microns. In a preferred embodiment, the paper wrapper may have a thickness of 40 microns.

[0368] In certain preferred embodiments, the wrapper may be formed from a laminate comprising a plurality of layers. Preferably, the wrapper is formed from an aluminium co-laminated sheet. In the event that the aerosol generating substrate should ignite rather than heat up in the intended manner, the use of a co-laminated sheet comprising aluminium advantageously prevents combustion of the aerosol generating substrate.

[0369] The paper layer of the co-laminated sheet may have a grammage of at least 35 gsm, preferably at least 40 gsm. The paper layer of the co-laminated sheet may have a grammage of less than or equal to 55 gsm, preferably less than or equal to 50 gsm. The paper layer of the co-laminated sheet may have a grammage of 35 gsm to 55 gsm, preferably 40 gsm to 50 gsm. In a preferred embodiment, the paper layer of the co-laminated sheet may have a grammage of 45 gsm.

[0370] The paper layer of the co-laminated sheet may have a thickness of at least 50 microns, preferably at least 55 microns, more preferably at least 60 microns. The paper layer of the co-laminated sheet may have a thickness of less than or equal to 80 microns, preferably less than or equal to 75 microns, more preferably less than or equal to 70 microns.

[0371] The paper layer of the co-laminated sheet may have a thickness of 50 to 80 microns, preferably 55 to 75 microns, more preferably 60 to 70 microns. In a preferred embodiment, the paper layer of the co-laminated sheet may have a thickness of 65 microns.

[0372] The metal layer of the co-laminated sheet may have a grammage of at least 12 gsm, preferably at least 15 gsm. The metal layer of the co-laminated sheet may have a grammage of less than or equal to 25 gsm, preferably less than or equal to 20 gsm. The metal layer of the co-laminated sheet may have a grammage of 12 gsm to 25 gsm, preferably 15 gsm to 20 gsm. In a preferred embodiment, the metal layer of the co-laminated sheet may have a grammage of 17 gsm.

[0373] The metal layer of the co-laminated sheet may have a thickness of at least 2 microns, preferably at least 3 microns, more preferably at least 5 microns. The metal layer of the co-laminated sheet may have a thickness of less than or equal to 15 microns, preferably less than or equal to 12 microns, more preferably less than or equal to 10 microns.

[0374] The metal layer of the co-laminated sheet may have a thickness of 2 to 15 microns, preferably 3 to 12 microns, more preferably 5 to 10 microns. In a preferred embodiment, the metal layer of the co-laminated sheet may have a thickness of 6 microns.

[0375] The packaging material defining the first aerosol generating segment and the second aerosol generating segment may be a paper packaging material containing PVOH (polyvinyl alcohol) or silicone (or polysiloxane) (or polysiloxane). Adding PVOH (polyvinyl alcohol) or silicone (or polysiloxane) may improve the grease barrier properties of the packaging material.

[0376] PVOH or silicone (or polysiloxane) may be applied as a surface coating to the paper layer, such as disposed on an outer surface of the paper layer of the wrapper defining the first aerosol generating segment and the second aerosol generating segment. PVOH or silicone (or polysiloxane) may be disposed on an outer surface of the paper layer of the wrapper and form a layer thereon. PVOH or silicone (or polysiloxane) may be disposed on an inner surface of the paper layer of the wrapper. PVOH or silicone (or polysiloxane) may be disposed on an inner surface of the paper layer of the aerosol generating article and form a layer thereon.

[0377] The paper packaging material containing PVOH or silicone (or polysiloxane) may have a grammage of at least 20 gsm, preferably at least 25 gsm, and more preferably at least 30 gsm. The paper packaging material containing PVOH or silicone (or polysiloxane) may have a grammage of less than or equal to 50 gsm, preferably less than or equal to 45 gsm, and more preferably less than or equal to 40 gsm.

[0378] The paper packaging material comprising PVOH or silicone (or polysiloxane) may have a thickness of at least 25 microns, preferably at least 30 microns, more preferably at least 35 microns. The paper packaging material comprising PVOH or silicone (or polysiloxane) may have a thickness of less than or equal to 50 microns, preferably less than or equal to 45 microns, more preferably less than or equal to 40 microns.

[0379] The package defining the first aerosol generating segment and the second aerosol generating segment may include a flame retardant composition comprising one or more flame retardant compounds. The term "flame retardant compound" is used herein to describe compounds that, when added to or otherwise incorporated into a carrier substrate (e.g., a paper or plastic compound), provide varying degrees of flammability protection to the carrier substrate. In practice, the flame retardant compound may be activated by the presence of an ignition source and is adapted to prevent or slow the further development of ignition by a variety of different physical and chemical mechanisms.

[0380] The flame retardant composition may also typically include one or more non-flame retardant compounds, i.e., one or more compounds (e.g., solvents, excipients, fillers) that do not actively contribute to providing flammability protection to the carrier substrate, but are used to facilitate the application of one or more flame retardant compounds to or in the packaging or both. Some non-flame retardant compounds of the flame retardant composition—e.g., solvents—are volatile and may evaporate from the packaging upon drying after the flame retardant composition is applied to or in the packaging base material or both. Thus, although such non-flame retardant compounds form part of the formulation of the flame retardant composition, in the packaging of the aerosol-generating article, they may no longer be present or they may only be detectable in trace amounts.

[0381] For example, the flame retardant composition may include a polymer and a mixed salt based on at least one monocarboxylic acid, dicarboxylic acid and / or tricarboxylic acid, at least one polyphosphoric acid, pyrophosphoric acid and / or phosphoric acid, and a hydroxide or salt of an alkali metal or alkaline earth metal, wherein the at least one monocarboxylic acid, dicarboxylic acid and / or tricarboxylic acid forms a carboxylate with the hydroxide or salt, and the at least one polyphosphoric acid, pyrophosphoric acid and / or phosphoric acid forms a phosphate with the hydroxide or salt. Preferably, the flame retardant composition may also include a carbonate of an alkali metal or an alkaline earth metal.

[0382] A non-exhaustive list of non-limiting examples is provided below.Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0383] Example 1: An aerosol generating system, comprising: an aerosol generating device for use with an aerosol generating article, the aerosol generating device comprising: a heating chamber for receiving the aerosol generating article, and a heater assembly arranged along a portion of the heating chamber defining a heating zone, and an aerosol generating article for receiving in the heating chamber of the aerosol generating device, the aerosol generating article comprising: a first aerosol generating segment and a second aerosol generating segment, the first aerosol generating segment comprising a first aerosol generating matrix, the second aerosol generating segment comprising a second aerosol generating matrix, the aerosol generating system being configured such that when the aerosol generating article is fully received in the heating chamber of the aerosol generating device: no more than 50% of the length of the first aerosol generating segment is within the heating zone, and at least 90% of the length of the second aerosol generating segment is within the heating zone.

[0384] Example 1a: An aerosol generating system, comprising: an aerosol generating device for use with an aerosol generating article, the aerosol generating device comprising: a heating chamber for receiving the aerosol generating article, and a heater assembly arranged along a portion of the heating chamber defining a heating zone, and an aerosol generating article for receiving in the heating chamber of the aerosol generating device, the aerosol generating article comprising: a first aerosol generating segment and a second aerosol generating segment, the first aerosol generating segment comprising a first aerosol generating matrix, the second aerosol generating segment comprising a second aerosol generating matrix, the aerosol generating system being configured such that when the aerosol generating article is fully received in the heating chamber of the aerosol generating device: at least 90% of the length of the second aerosol generating segment is within the heating zone.

[0385] Example 1b: An aerosol generating system according to example 1 or example 1a, wherein the first aerosol generating segment is located upstream of the second aerosol generating segment.

[0386] Example 1c: An aerosol generating system according to any preceding example, wherein the length of the first aerosol generating segment is smaller than the length of the second aerosol generating segment.

[0387] Example 1d: An aerosol generating system according to any preceding example, wherein the second aerosol generating segment has a length between 9 mm and 15 mm.

[0388] Example 1e: An aerosol generating system according to any preceding example, wherein a combined length of the first aerosol generating segment and the second aerosol generating segment is between 15 mm and 25 mm.

[0389] Example 3: An aerosol-generating system according to any preceding example, wherein the first aerosol-generating segment has an upstream end, the upstream end of the first aerosol-generating segment defining an upstream end of the aerosol-generating article.

[0390] Example 4: An aerosol generating system according to any preceding example, wherein the upstream end of the second aerosol generating segment is in direct contact with the downstream end of the first aerosol generating segment.

[0391] Example 6: An aerosol generating system according to any preceding example, wherein the length of the second aerosol generating segment is at least 3 mm greater than the length of the first aerosol generating segment.

[0392] Example 8: An aerosol generating system according to any preceding example, wherein the first aerosol generating segment has a length of at least 2 millimeters.

[0393] Example 9: An aerosol generating system according to any preceding example, wherein the first aerosol generating segment has a length of no more than 8 millimeters.

[0394] Example 10: An aerosol generating system according to any preceding example, wherein the second aerosol generating segment has a length of at least 8 millimeters.

[0395] Example 11: An aerosol generating system according to any preceding example, wherein the second aerosol generating segment has a length of no more than 16 millimeters.

[0396] Example 12: An aerosol generating system according to any preceding example, wherein the heater assembly comprises at least one of a resistive heating element and an inductive heating assembly.

[0397] Example 12a: An aerosol generating system according to any preceding example, wherein the heater assembly comprises an induction heating element and an inductor coil.

[0398] Example 13: An aerosol-generating system according to any preceding example, wherein the first aerosol-generating substrate has a first density and the second aerosol-generating substrate has a second density, the second density being greater than the first density.

[0399] Example 14. An aerosol-generating article according to any preceding example, wherein the density of the second aerosol-generating substrate is at least 100 mg / cm3 higher than the density of the first aerosol-generating substrate.

[0400] Example 15: An aerosol-generating system according to any preceding example, wherein the density of the first aerosol-generating substrate is less than 400 mg / cm3.

[0401] Example 16. An aerosol-generating article according to any preceding example, wherein the first aerosol-generating substrate has a density between 100 mg / cm3 and 400 mg / cm3.

[0402] Example 17: An aerosol-generating system according to any preceding example, wherein the second aerosol-generating substrate has a density of at least 500 mg / cm3.

[0403] Example 18. An aerosol-generating article according to any preceding example, wherein the second aerosol-generating substrate has a density between 500 mg / cm3 and 1000 mg / cm3.

[0404] Example 19. An aerosol-generating article according to any preceding example, wherein the density of the second aerosol-generating substrate is at least 1.2 times the density of the first aerosol-generating substrate.

[0405] Example 20. An aerosol-generating article according to any preceding example, wherein the first aerosol-generating substrate comprises shredded tobacco material.

[0406] Example 21: An aerosol-generating system according to Example 20, wherein the first aerosol-generating substrate comprises tobacco cut filler.

[0407] Example 22. An aerosol-generating article according to any preceding example, wherein the first aerosol-generating substrate comprises a shredded sheet of homogenised tobacco material.

[0408] Example 23. An aerosol-generating article according to any preceding example, wherein the second aerosol-generating substrate comprises an aerosol-generating film.

[0409] Example 24: An aerosol-generating system according to Example 23, wherein the second aerosol-generating substrate comprises an aerosol-generating film, the aerosol-generating film comprising a cellulose-based film-forming agent, nicotine and glycerol, wherein the aerosol-generating film has a glycerol content of at least 40% by weight.

[0410] Example 25. An aerosol-generating article according to example 24, wherein the second aerosol-generating substrate comprises at least 50% by weight glycerol.

[0411] Example 26. An aerosol-generating article according to any one of examples 23 to 25, wherein the aerosol-generating film comprises a cellulose film-forming agent, nicotine, and an aerosol former.

[0412] Example 27. An aerosol-generating article according to any one of examples 23 to 26, wherein the aerosol-generating film further comprises a cellulose-based reinforcement agent.

[0413] Example 28. An aerosol-generating article according to any one of examples 23 to 27, wherein the aerosol-generating film further comprises carboxymethyl cellulose.

[0414] Example 29. An aerosol-generating article according to any one of examples 23 to 28, wherein the aerosol-generating film further comprises an acid.

[0415] Example 30. An aerosol-generating article according to any one of examples 23 to 29, wherein the aerosol-generating film is substantially free of tobacco.

[0416] Example 31. An aerosol-generating article according to any preceding example, wherein the second aerosol-generating substrate comprises a gel composition comprising nicotine, at least one gelling agent, and an aerosol former.

[0417] Example 32: An aerosol generating system according to any of the preceding examples, wherein the first aerosol generating substrate and the second aerosol generating substrate comprise at least one aerosol former, and the aerosol former content of the second aerosol generating substrate is greater than the aerosol former content of the first aerosol generating substrate.

[0418] Example 33: An aerosol-generating system according to any preceding example, wherein the first aerosol-generating substrate comprises at least one aerosol-forming agent, and wherein the aerosol-forming agent content of the first aerosol-generating substrate does not exceed 30 wt% on a dry weight basis.

[0419] Example 34: An aerosol generating system according to example 32 or example 33, wherein the second aerosol generating substrate comprises at least one aerosol former, and wherein the aerosol former content of the second aerosol generating substrate is at least 40 wt% on a dry weight basis.

[0420] Example 35. An aerosol-generating article according to any one of examples 32 to 34, wherein the aerosol-forming agent content of the second aerosol-generating substrate is at least 15% higher than the aerosol-forming agent content of the first aerosol-generating substrate.

[0421] Example 36. An aerosol-generating article according to any one of examples 32 to 35, wherein the aerosol-forming agent content of the second aerosol-generating substrate is at least 1.2 times the aerosol-forming agent content of the first aerosol-generating substrate.

[0422] Example 37: An aerosol-generating article according to any one of examples 32 to 36, wherein the aerosol-forming agent content of the first aerosol-generating substrate is between 5 wt% and 30 wt% on a dry weight basis.

[0423] Example 38. An aerosol-generating article according to any one of examples 32 to 37, wherein the aerosol-forming agent content of the second aerosol-generating substrate is between 40 wt% and 80 wt% on a dry weight basis.

[0424] Example 39: An aerosol-generating system according to any preceding example, wherein the first aerosol-generating substrate of the first aerosol-generating segment is defined by a first wrapper, and wherein the second aerosol-generating substrate of the second aerosol-generating segment is defined by a second wrapper.

[0425] Example 40. An aerosol-generating article according to any preceding example, wherein the aerosol-generating strip further comprises a third aerosol-generating segment disposed upstream of the second aerosol-generating segment and comprising a third aerosol-generating substrate.

[0426] Example 41. An aerosol-generating article according to example 40, wherein the third aerosol-generating substrate comprises shredded tobacco material.

[0427] Example 42. An aerosol-generating article according to example 40 or example 41, wherein the third aerosol-generating substrate comprises at least one aerosol former, and wherein the aerosol former content of the third aerosol-generating substrate does not exceed 30 wt% on a dry weight basis.

[0428] Example 43 The aerosol-generating article of any preceding example, further comprising a downstream segment disposed downstream of the first aerosol-generating segment and the second aerosol-generating segment.

[0429] Example 44. An aerosol-generating article according to example 43, wherein the downstream section extends to a downstream end of the aerosol-generating article.

[0430] Example 45. An aerosol-generating article according to example 43 or example 44, wherein the downstream segment comprises a downstream filter segment.

[0431] Example 46. An aerosol-generating article according to example 45, wherein the downstream filter segment is a solid rod.

[0432] Example 47. An aerosol-generating article according to example 44 and example 46, wherein the downstream filter segment has a length of at least 5 millimeters.

[0433] Example 48. An aerosol-generating article according to any one of examples 43 to 47, wherein the downstream section comprises a hollow tubular cooling element.

[0434] Example 49. An aerosol-generating article according to example 48, wherein the hollow tubular cooling element has a length of at least 20 millimeters.

[0435] Example 50. An aerosol-generating article according to example 48 or example 49, wherein the downstream segment comprises a ventilation zone at a location along the hollow tubular cooling element.

[0436] Example 51. An aerosol-generating article according to any one of examples 48 to 50, wherein the downstream section further comprises a hollow tubular support element upstream of the hollow tubular cooling element.

[0437] Example 52. An aerosol-generating article according to any one of examples 48 to 51, wherein the downstream section further comprises a downstream hollow tubular element downstream of the hollow tubular cooling element.

[0438] Example 53 The aerosol-generating article of any preceding example, further comprising an upstream element disposed upstream of the first aerosol-generating segment and the second aerosol-generating segment.

[0439] Example 54. An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has a ventilation level of at least 40%.

[0440] Example 55. An aerosol-generating article according to any preceding example, wherein the length of the aerosol-generating article is between 40 mm and 50 mm.

[0441] Example 56. An aerosol-generating article according to any one of examples 1 to 55, wherein the length of the aerosol-generating article is between 70 mm and 80 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0442] The present invention will be further described below with reference to the accompanying drawings, in which:

[0443] Figure 1 shows a schematic side perspective view of a first aerosol-generating article for use in an aerosol-generating system according to the present invention;

[0444] Figure 2 A schematic side cross-sectional view of a first aerosol generating system according to the present invention is shown, the first aerosol generating system comprising Figure 1 a first aerosol-generating article;

[0445] Figure 3 shows a schematic side cross-sectional view of a second aerosol generating system according to the present invention, the second aerosol generating system comprising a second aerosol generating article;

[0446] Figure 4 shows a schematic side perspective view of a third aerosol-generating article for use in an aerosol-generating system according to the present invention;

[0447] Figure 5 A schematic side cross-sectional view of a third aerosol generating system according to the present invention is shown, the third aerosol generating system comprising Figure 4 A third aerosol-generating article. DETAILED DESCRIPTION

[0448] Figure 1 The aerosol generating article 10 shown in the figure includes a first aerosol generating segment 24, a second aerosol generating segment 26 and a downstream segment 14. The upstream end of the first aerosol generating segment 24 defines the upstream end 16 of the aerosol generating article 10. The second aerosol generating segment 26 is located immediately downstream of the first aerosol generating segment 24. The downstream end of the first aerosol generating segment 24 is adjacent to the upstream end of the second aerosol generating segment 26. The downstream segment 14 is located immediately downstream of the second aerosol generating segment 26. The downstream end of the second aerosol generating segment 26 is adjacent to the upstream end of the downstream segment 14. The downstream end of the downstream segment 14 defines the downstream end 18 of the aerosol generating article 10.

[0449] The downstream section 14 includes the hollow tubular cooling element 20 and a downstream filter segment 50 .

[0450] The aerosol-generating article 10 has an overall length of approximately 45 mm and an outer diameter of approximately 7.2 mm.

[0451] The first aerosol generating segment 24 has a length of 5 mm and comprises a first aerosol generating substrate formed of about 50 mg of shredded tobacco material, the first aerosol generating substrate comprising between 15% and 20% by weight of glycerol. The density of the first aerosol generating substrate is about 300 mg / cm3. The first aerosol generating segment 24 is individually wrapped by a stick pack (not shown).

[0452] The second aerosol-generating segment 26 has a length of 12 mm and comprises a second aerosol-generating substrate formed from fragments of an aerosol-generating film. An exemplary composition of the aerosol-generating film is shown in Table 1 below:

[0453] Table 1: Aerosol-generating film compositions

[0454] As indicated above, the second aerosol-generating substrate has a glycerol content of about 50% by weight, thus being more than 10% higher than the glycerol content of the first aerosol-generating substrate. The density of the second aerosol-generating substrate is higher than 600 mg / cm3. The first aerosol-generating segment 24 is individually wrapped by a stick package (not shown).

[0455] The hollow tubular cooling element 20 of the downstream section 14 is located immediately downstream of the aerosol generating strip 12, the hollow tubular cooling element 20 being longitudinally aligned with the strip 12. The upstream end of the hollow tubular cooling element 20 abuts the downstream end of the strip 12.

[0456] The hollow tubular cooling element 20 defines a hollow section of the aerosol-generating article 10. The hollow tubular cooling element 20 does not substantially affect the overall RTD of the aerosol-generating article. In more detail, the RTD of the hollow tubular cooling element 20 is about 0 mmH2O.

[0457] The hollow tubular cooling element 20 is provided in the form of a hollow cylindrical tube made of paperboard. The hollow tubular cooling element 20 defines an inner cavity extending from the upstream end of the hollow tubular cooling element 20 to the downstream end of the hollow tubular cooling element 20. The inner cavity is substantially empty and thus substantially unrestricted airflow is achieved along the inner cavity.

[0458] The hollow tubular cooling element 20 has a length of about 21 mm, an outer diameter of about 7.2 mm, and an inner diameter of about 6.7 mm. Therefore, the thickness of the outer peripheral wall of the hollow tubular cooling element 20 is about 0.25 mm.

[0459] The aerosol-generating article 10 comprises a ventilation zone 30 disposed at a location along the hollow tubular cooling element 20. The ventilation zone 30 comprises a row of circumferential openings or perforations defining the hollow tubular cooling element 20. The perforations of the ventilation zone 30 extend through the wall of the hollow tubular cooling element 20 so as to allow fluid to enter the interior cavity from the exterior of the article 10. The ventilation level of the aerosol-generating article 10 is about 40%.

[0460] The downstream filter segment 50 extends from the downstream end of the hollow tubular cooling element 20 to the downstream or mouth end of the aerosol generating article 10. The downstream filter segment 50 has a length of about 7 mm. The outer diameter of the downstream filter segment 50 is about 7.2 mm. The downstream filter segment 50 includes a low density cellulose acetate filter segment. The RTD of the downstream filter segment 50 is about 8 mmH2O. The downstream filter segment 50 can be individually wrapped by a stick package (not shown).

[0461] The article 10 includes an upstream wrapper 44 that defines the first aerosol generating segment 24, the second aerosol generating segment 26, and the hollow tubular cooling element 20. The ventilation zone 30 may also include a row of circumferential perforations disposed on the upstream wrapper 44. The perforations of the upstream wrapper 44 overlap the perforations disposed on the hollow tubular cooling element 20. Thus, the upstream wrapper 44 overlies the perforations of the ventilation zone 30 disposed on the hollow tubular cooling element 20.

[0462] The article 10 further includes a tipping wrapper 52 defining the hollow tubular cooling element 20 and the mouthpiece element 50. The tipping wrapper 52 overlies the portion of the upstream wrapper 44 overlying the hollow tubular cooling element 20. In this way, the tipping wrapper 52 effectively joins the mouthpiece element 50 to the remaining components of the article 10. The tipping wrapper 52 has a width of about 26 millimeters. Additionally, the ventilation zone 30 may include a row of circumferential perforations disposed on the tipping wrapper 52. The perforations of the tipping wrapper 52 overlap the perforations disposed on the hollow tubular cooling element 20 and the upstream wrapper 44. Thus, the tipping wrapper 52 overlies the perforations of the ventilation zone 30 disposed on the hollow tubular cooling element 20 and the upstream wrapper 44.

[0463] Figure 2 A first aerosol generating system 100 according to the present invention is shown. The first aerosol generating system 100 comprises Figure 1 The aerosol generating device 1 comprises a first aerosol generating article 10, and a downstream portion of the aerosol generating device 1. The aerosol generating device 1 comprises a housing (or body) 4, which extends between a downstream end 2 and an upstream end (not shown). The housing 4 comprises a peripheral wall 6. The peripheral wall 6 defines a heating chamber 3 for receiving the aerosol generating article 10. The heating chamber 3 is defined by a closed upstream end and an open downstream end. The downstream end of the heating chamber 3 is located at the downstream end of the aerosol generating device 1. The aerosol generating article 10 is configured to be received by the open downstream end of the heating chamber 3, and is configured to be adjacent to the closed upstream end of the device cavity when the aerosol generating article 10 is fully received in the heating chamber 3.

[0464] The device airflow channel 5 is defined within the peripheral wall 6. The airflow channel 5 extends between an inlet 7 located at the mouth end of the aerosol generating device 1 and the closed end of the device cavity. Air can enter the aerosol generating substrate 12 via an orifice (not shown) provided at the closed end of the device cavity to ensure fluid communication between the airflow channel 5 and the aerosol generating substrate 12.

[0465] The aerosol generating device 1 further comprises a heater assembly 15 and a power source (not shown) for powering the heater assembly 15. A controller (not shown) is also provided to control the supply of power to the heater assembly 15. The heater assembly 15 is configured to controllably heat the aerosol generating article 10 when the aerosol generating article 10 is fully received within the heating chamber 3 during use.

[0466] The heater assembly 15 extends from an upstream end to a downstream end, thereby defining a heating zone. The heater assembly 15 has the same length as the second aerosol generating segment 26, so that when the aerosol generating article 10 is fully received in the heating chamber 3, the entire length of the second aerosol generating segment 26 is received in the heating zone to provide optimal heating of the aerosol generating segment 26. When the aerosol generating article 10 is fully received in the heating chamber 3, the first aerosol generating segment 24 is arranged upstream of the heating zone, so that no length of the first aerosol generating segment 24 is arranged in the heating zone. The heater assembly 15 includes a resistive heating element. When the aerosol generating article 10 is fully received in the heating chamber 3, the upstream portion of the hollow tubular cooling element 20 is also received in the heating chamber 3. The length of this upstream portion of the hollow tubular cooling element 20 is 11 mm. Therefore, about 28 mm of the article 10 is received in the heating chamber 3, and about 17 mm of the article 10 is located outside the heating chamber 3. In other words, when the article 10 is fully received within the heating chamber 3 , the article 10 protrudes from the device 1 by approximately 17 millimeters. Figure 2 This length PL of the article 10 protruding from the device 1 is shown.

[0467] The ventilation zone 30 is arranged to be exposed when the aerosol-generating article 10 is fully received within the heating chamber 3 .

[0468] When in use, the aerosol generating article 10 is completely received in the heating chamber 3 of the aerosol generating device 1. The heater assembly 15 is activated by the controller, and the resistive heating element generates heat, which is directly transferred to the second aerosol generating segment 26 disposed in the heating zone. This generates an aerosol in the second aerosol generating substrate. The first aerosol generating segment 24, which is not located in the heating zone, heats more slowly and to a lower temperature than the second aerosol generating segment 26. However, due to the density and aerosol former content, the first aerosol generating substrate also generates an aerosol. When a pressure drop is applied to the downstream end of the aerosol generating article 10, air is drawn into the air inlet 7 and along the airflow channel 5, and into the first aerosol generating segment 24. The aerosol generated in the first aerosol generating substrate and the second aerosol generating substrate is entrained in the airflow, which then passes through the downstream section before leaving through the downstream end of the aerosol generating article.

[0469] Figure 3 A second aerosol generating system 200 according to the present invention is shown. The second aerosol generating system 200 comprises the same Figure 2 The aerosol generating device 1 described in the embodiment is the same as the aerosol generating device 1. The second aerosol generating system 200 further includes an aerosol generating article 12. The aerosol generating article 12 includes Figure 1 and Figure 2 The aerosol-generating article 10 of the present embodiment has all the same features as those of the aerosol-generating article 10 of the present embodiment.

[0470] Figure 3 The aerosol generating article 12 is different from Figure 1 and Figure 2 aerosol generating article 10, because the first aerosol generating segment 24 has a length of 8.5 mm and the second aerosol generating segment has a length of 8.5 mm. This means that when the aerosol generating article 12 is fully received in the heating chamber 3 of the aerosol generating article 1, the downstream portion of the first aerosol generating segment 24 is disposed within the heating zone of the heater assembly 15. In particular, Figure 3 In the aerosol generating system 200 of , the downstream 3.5 mm of the first aerosol generating segment 24 is arranged within the heating zone of the heater assembly 15. This means that in use, a portion of the first aerosol generating segment 24 is directly heated by the heater assembly.

[0471] Figure 4 A third aerosol-generating article for use in an aerosol-generating system according to the invention is shown. Figure 4 The aerosol generating article 110 shown includes Figure 1 All of the same features of the aerosol-generating article 10 of Figure 4In the aerosol-generating article 110 of FIG. 1 , the second aerosol-generating segment 126 has a length of 7 mm. The third aerosol-generating segment 128 is disposed between the second aerosol-generating segment 126 and the downstream segment 14. The third aerosol-generating segment 128 has a length of 5 mm.

[0472] The third aerosol generating segment 128 comprises a third aerosol generating substrate. The third aerosol generating substrate comprises shredded tobacco material and contains between 15% and 20% by weight of glycerol. The bulk density of the third aerosol generating substrate is about 250 mg / cm3. The third aerosol generating segment 128 is individually wrapped by a stick package (not shown).

[0473] Figure 5 FIG. 3 shows a third aerosol generating system according to the present invention. The third aerosol generating system 300 comprises the same Figure 2 The aerosol generating device 1 described in the embodiment is the same as the aerosol generating device 1. The aerosol generating system 300 also includes Figure 4 An aerosol-generating article 110.

[0474] As can be seen, when the aerosol-generating article 110 is fully received within the heating chamber 3 of the aerosol-generating device, both the second aerosol-generating segment and the third aerosol-generating segment are within the heating zone of the heater assembly 15 .

[0475] For the purpose of this specification and the appended claims, unless otherwise stated, all numbers representing amounts, quantities, percentages, etc. should be understood to be modified by the term "about" in all cases. Moreover, all ranges include disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed herein. Therefore, in this article, the number A is understood to be ± 10% of A. In this article, the number A may be considered to be included in the numerical value within the general standard error of the measurement of the property modified by the number A. In some cases as used in the appended claims, the number A may deviate from the percentages listed above, as long as the amount of A deviation does not significantly affect the basic and novel features of the claimed invention. Moreover, all ranges include disclosed maximum and minimum points, and include any intermediate ranges therein that may be specifically listed or may not be listed herein.

Claims

1. An aerosol generating system comprising: An aerosol generating device for use with an aerosol generating article, the aerosol generating device comprising: a heated chamber for receiving the aerosol-generating article, and a heater assembly disposed along a portion of the heating chamber defining a heating zone, and An aerosol-generating article for receipt in a heating chamber of the aerosol-generating device, the aerosol-generating article comprising: a first aerosol-generating segment and a second aerosol-generating segment, the first aerosol-generating segment comprising a first aerosol-generating substrate, the second aerosol-generating segment comprising a second aerosol-generating substrate, The aerosol generating system is configured such that when the aerosol generating article is fully received within the heating chamber of the aerosol generating device: At least 90% of the length of the second aerosol generating segment is within the heating zone, wherein The first aerosol generating segment is located upstream of the second aerosol generating segment, and The length of the first aerosol generating segment is shorter than the length of the second aerosol generating segment.

2. An aerosol-generating system according to claim 1, wherein the first aerosol-generating segment has an upstream end, the upstream end of the first aerosol-generating segment defining an upstream end of the aerosol-generating article.

3. An aerosol generating system according to claim 1 or claim 2, wherein the upstream end of the second aerosol generating segment is in direct contact with the downstream end of the first aerosol generating segment.

4. An aerosol generating system according to any preceding claim, wherein the first aerosol generating segment has a length of at least 2 millimetres.

5. An aerosol generating system according to any preceding claim, wherein the first aerosol generating segment has a length of no more than 8 millimetres.

6. An aerosol generating system according to any preceding claim, wherein the second aerosol generating segment has a length of at least 8 millimetres.

7. An aerosol generating system according to any preceding claim, wherein the second aerosol generating segment has a length of no more than 16 millimetres.

8. An aerosol generating system according to any preceding claim, wherein the heater assembly comprises at least one of a resistive heating element and an inductive heating assembly.

9. An aerosol generating system according to any preceding claim, wherein the first aerosol-generating substrate has a first density and the second aerosol-generating substrate has a second density, the second density being greater than the first density.

10. An aerosol generating system according to any preceding claim, wherein the first aerosol generating substrate and the second aerosol generating substrate comprise at least one aerosol former, the aerosol former content of the second aerosol generating substrate being greater than the aerosol former content of the first aerosol generating substrate.

11. An aerosol generating system according to any preceding claim, wherein the first aerosol-generating substrate comprises at least one aerosol-forming agent, and wherein the aerosol-forming agent content of the first aerosol-generating substrate does not exceed 30 wt% on a dry weight basis.

12. An aerosol generating system according to any preceding claim, wherein the second aerosol-generating substrate comprises at least one aerosol-forming agent, and wherein the aerosol-forming agent content of the second aerosol-generating substrate is at least 40 wt-% on a dry weight basis.

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