JP2025521638A - Aerosol-generating article comprising an airflow guide element extending within a tubular substrate - Patents.com - Google Patents

Abstract

An aerosol-generating article (1, 2, 3, 4, 5) for generating an inhalable aerosol upon heating is provided. The aerosol-generating article comprises an aerosol-generating substrate (40) in the form of a hollow tubular segment defining a substrate cavity (44) extending from an upstream end of the aerosol-generating substrate to a downstream end of the aerosol-generating substrate. The aerosol-generating article comprises an airflow guiding element (20) extending longitudinally into the substrate cavity and defining an airflow channel (22) between an outer surface of the airflow guiding element and an inner surface of the aerosol-generating substrate. The width or diameter of the airflow guiding element is smaller than the diameter of the substrate cavity.

Description

The present invention relates to an aerosol-generating article comprising a rod of an aerosol-generating substrate adapted to generate an inhalable aerosol upon heating.

Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. Typically, in such heated smoking articles, an aerosol is generated by transferring heat from a heat source to a physically separate aerosol-generating substrate or material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

Numerous prior art documents disclose aerosol generating devices for consuming aerosol generating articles. Such devices include, for example, electrically heated aerosol generating devices in which the aerosol is generated by heat transfer from one or more electric heater elements of the aerosol generating device to an aerosol generating substrate of the heated aerosol generating article. For example, an electrically heated aerosol generating device has been proposed that comprises an internal heater blade adapted to be inserted into the aerosol generating substrate. The use of an aerosol generating article in combination with an external heating system is also known. For example, WO 2020/115151 describes the provision of an external heating element arranged around the periphery of the aerosol generating article when the aerosol generating article is received in the cavity of the aerosol generating device. Alternatively, an inductively heated aerosol generating article is proposed by WO 2015/176898, comprising an aerosol generating substrate and a susceptor disposed within the aerosol generating substrate.

In general, it can be difficult to provide efficient heating of the aerosol-generating substrate throughout the entire rod of substrate. While the portion of the substrate closest to the heating element will necessarily be heated most effectively, imperfect heat transfer through the substrate means that the portions of the substrate furthest from the heating element may not be heated effectively. Thus, aerosol generation from those portions of the substrate that are not effectively heated will not be optimal, and in some cases the portions of the substrate may never reach a high enough temperature to generate aerosol during use. For example, as discussed above, if an external heating element is used to heat the rod of the aerosol-generating substrate, the central portion of the rod of the aerosol-generating substrate is not likely to generate as much aerosol as the outer portions of the rod, and in some cases may not generate any aerosol at all. Thus, overall, aerosol generation from the aerosol-generating rod may be inefficient, and portions of the aerosol-generating substrate are potentially wasted.

In addition, aerosol is generally not immediately generated by the aerosol-generating substrate upon activation of the heating element. This is because there is a preheat period following activation of the heating element during which the aerosol-generating substrate is heated to the temperature required for aerosol generation. Thus, there may be a relatively long duration between activation of the heating element and generation of a sensory acceptable aerosol for inhalation by the user.

It would therefore be desirable to provide an aerosol-generating article having an aerosol-generating substrate adapted to provide more efficient aerosolization of the aerosol-generating substrate, reducing waste of substrate material such as tobacco. It would also be desirable to provide such an aerosol-generating article that may achieve a relatively short pre-heat time, such that a sensory acceptable aerosol can be delivered to a user immediately upon initiation of heating of the aerosol-generating substrate. It would be desirable to provide such an aerosol-generating article that may provide optimized delivery of aerosol from the aerosol-generating substrate. It would be particularly desirable to provide such an aerosol-generating article in a relatively simple design, such that it may be manufactured in a cost-effective manner and incorporated into existing product designs. It would further be desirable to provide such an article that may be readily adapted to be heated with various types of heating devices, including induction and resistance heating devices.

An aerosol-generating article for generating an inhalable aerosol upon heating is provided. The aerosol-generating article may include an aerosol-generating substrate. The aerosol-generating substrate may be in the form of a hollow tubular segment defining a substrate cavity extending between an upstream end of the aerosol-generating substrate and a downstream end of the aerosol-generating substrate. The aerosol-generating article may include an airflow guiding element. The airflow guiding element may extend longitudinally into the substrate cavity. The airflow guiding element may include an elongated body extending longitudinally into the substrate cavity. An airflow channel may be defined between an outer surface of the airflow guiding element and an inner surface of the aerosol-generating substrate. The width or diameter of the airflow guiding element may be less than the diameter of the substrate cavity. The aerosol-generating substrate may be referred to as a hollow tubular substrate.

The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:

1 shows a schematic cross-sectional side view of an aerosol-generating article according to one embodiment of the present invention. 2 shows a schematic cross-sectional view of the aerosol-generating article shown in FIG. 1 taken along the cutting plane line XX. 1 shows a schematic cross-sectional side view of an aerosol-generating article according to one embodiment of the present invention. 1 shows a schematic cross-sectional side view of an aerosol-generating article according to one embodiment of the present invention. 1 shows a schematic cross-sectional side view of an aerosol-generating article according to one embodiment of the present invention. 1 shows a schematic cross-sectional side view of an aerosol-generating article according to one embodiment of the present invention. 5 shows a schematic cross-sectional side view of a portion of an aerosol generating system including the aerosol generating article shown in FIG. 4 and an aerosol generating device. 1 shows a schematic cross-sectional side view of an aerosol-generating article according to one embodiment of the present invention.

According to the present invention, there is provided an aerosol-generating article for generating an inhalable aerosol upon heating. The aerosol-generating article comprises an aerosol-generating substrate. The aerosol-generating substrate is in the form of a hollow tubular segment defining a substrate cavity extending between an upstream end of the aerosol-generating substrate and a downstream end of the aerosol-generating substrate. The aerosol-generating article comprises an airflow guiding element. The airflow guiding element extends longitudinally within the substrate cavity. An airflow channel is defined between an outer surface of the airflow guiding element and an inner surface of the aerosol-generating substrate. The width or diameter of the airflow guiding element may be less than the diameter of the substrate cavity. The aerosol-generating substrate may be referred to as a hollow tubular substrate.

As used herein in connection with this disclosure, the term "aerosol-generating article" is used to describe an article that includes an aerosol-generating substrate that is heated to generate an inhalable aerosol for delivery to a user.

As used herein in connection with the present disclosure, the term "aerosol-generating substrate" is used to describe a substrate that includes an aerosol-generating material capable of releasing a volatile compound that can generate an aerosol upon heating.

As used herein with respect to this disclosure, the term "aerosol" is used to describe a dispersion of solid particles, or liquid droplets, or a combination of solid particles and liquid droplets, in a gas. Aerosols may be visible or invisible. Aerosols may include not only vapors of substances that are normally liquids or solids at room temperature, but also solid particles or liquid droplets, or a combination of solid particles and liquid droplets.

Aerosol-generating articles according to the present disclosure have a downstream end through which aerosol exits the aerosol-generating article for delivery to a user during use. The downstream end of the aerosol-generating article may also be referred to as the proximal end or mouth end of the aerosol-generating article. During use, a user directly or indirectly sucks on the downstream end of the aerosol-generating article to inhale the aerosol generated by the aerosol-generating article.

An aerosol-generating article according to the present disclosure has an upstream end. The upstream end is opposite the downstream end. The upstream end of the aerosol-generating article may also be referred to as the distal end of the aerosol-generating article.

Components of an aerosol-generating article according to the present disclosure may be described as being upstream or downstream of one another based on their relative location between the upstream end of the aerosol-generating article and the downstream end of the aerosol-generating article.

As used herein in connection with the present invention, the term "longitudinal direction" refers to the direction between an upstream end and an opposing downstream end of an aerosol-generating article.

As used herein in connection with this disclosure, the term "transverse" is used to describe the direction perpendicular to the longitudinal axis.

As used herein with respect to this disclosure, the term "cross section" is used to refer to a transverse cross section of an aerosol-generating article, or a component thereof, unless otherwise indicated.

The term "radial" as used herein in connection with this disclosure describes a direction identified by a line extending in a plane perpendicular to the central longitudinal axis of the aerosol-generating article and passing through the point where the central longitudinal axis intersects the perpendicular plane. Thus, the term "radial" as used herein in connection with this disclosure refers to a direction perpendicular to the central longitudinal axis, for example, when describing an aerosol-generating article having a substantially cylindrical shape.

As used herein in connection with the present disclosure, the terms "hollow tubular element" and "hollow tubular substrate element" generally refer to an elongated element that defines a lumen, cavity, or airflow passage along its longitudinal axis. In particular, the term "tubular" is used in reference to a tubular element that has a substantially cylindrical cross-section and defines 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 will be appreciated that alternative shapes (e.g., alternative cross-sectional shapes) of the tubular element may be possible. The hollow tubular element may be an individual, separate element of an aerosol-generating article having a defined length and thickness. The terms "hollow tubular substrate" or "hollow tubular substrate element" refer to an aerosol-generating substrate in the form of a hollow tube.

As used herein in connection with the present disclosure, the term "homogenized tobacco material" encompasses any material formed by agglomeration of tobacco particles. Homogenized tobacco material may be produced by casting, extrusion, a papermaking process, or any other suitable process known in the art.

The term "tobacco particles" as used herein in connection with this disclosure describes particles of any plant member of the genus Nicotiana. The term "tobacco particles" encompasses ground or powdered tobacco lamina, ground or powdered tobacco stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during tobacco processing, handling, and shipping. Preferably, tobacco particles are substantially entirely derived from tobacco lamina. In contrast, isolated nicotine and nicotine salts, although compounds derived from tobacco, are not considered tobacco particles for purposes of this disclosure.

By providing a substrate element in a tubular form, the amount of tobacco material in the aerosol-generating substrate may advantageously be optimized so that an aerosol may be efficiently generated from the aerosol-generating substrate upon heating. Furthermore, the tubular form eliminates a central portion of the homogenized tobacco material that may not be heated as effectively as the outer portions, particularly in aerosol generating devices equipped with external heating means. Overall, therefore, the amount of tobacco material may be significantly reduced compared to a conventional solid plug of homogenized tobacco material, reducing tobacco waste. For example, it has been found that the amount of tobacco material used in a hollow tubular substrate element of an aerosol-generating article according to the present disclosure may be reduced by up to 40 percent compared to the amount of tobacco material used in a solid plug of a substrate of a conventional aerosol-generating article, while still maintaining a similar delivery of aerosol to the consumer.

The amount of tobacco material provided within the substrate can be easily adapted by controlling the parameters of the hollow tubular substrate element, such as the density and wall thickness of the peripheral wall of the hollow tubular substrate element. In this way, it is possible to adapt the hollow tubular substrate element so that it matches the heating zone of the associated aerosol generating device. Thus, the proportion of the aerosol-generating substrate that can be heated to the temperature required for aerosol generation is maximized so that aerosol generation from the aerosol-generating substrate is optimized.

The hollow tubular substrate element has a relatively simple structure that can be manufactured in a simple and cost-effective manner using existing equipment. The hollow tubular substrate element can then be incorporated into an aerosol-generating article with other components using known assembly methods and equipment.

By providing a longitudinally extending airflow guiding element within the empty substrate cavity defined by the hollow tubular aerosol-generating substrate, an airflow channel or path is defined around the airflow guiding element between the outer surface of the airflow guiding element and the interior of the aerosol-generating substrate such that air entering the substrate cavity is encouraged to flow near the inner surface of the aerosol-generating substrate. The protrusion of the airflow guiding element into the cavity effectively provides an airflow path having a reduced cross-section relative to the cross-section of the cavity, such that air entering the cavity may be locally accelerated as it flows through such airflow path in accordance with Bernoulli's theorem. Such local airflow acceleration may enhance the extraction of aerosol-forming components from the heated aerosol-generating substrate, which is particularly important for tubular substrates with an empty core. As a result, this airflow arrangement may improve aerosol delivery resulting from the hollow tubular substrate and reduce the time required for the substrate to generate a sensory acceptable aerosol after being initially heated, while reducing manufacturing costs and potential waste of substrate material that may not have contributed to aerosol generation.

The hollow tubular substrate element is preferably formed from homogenized tobacco material. The hollow tubular substrate element is preferably formed from one or more layers of homogenized tobacco material, such as cast leaf.

The hollow tubular substrate element is preferably formed of two or more overlapping layers of homogenized tobacco material, more preferably three or more overlapping layers of homogenized tobacco material.

The hollow tubular substrate element is preferably formed of up to about 10 overlapping layers of homogenized tobacco material, more preferably up to about 5 overlapping layers of homogenized tobacco material. For example, the hollow tubular substrate element may be formed of from about 2 to about 10 overlapping layers of homogenized tobacco material, or from about 3 to about 5 overlapping layers of homogenized tobacco material.

The multiple overlapping layers of homogenized tobacco material preferably directly overlie one another such that adjacent layers are in direct contact with one another without an intermediate layer.

The multi-layer arrangement of layers can provide a relatively dense structure with sufficient structural rigidity to provide an aerosol-generating substrate within an aerosol-generating article without the need for any additional support, such as a carrier layer or internal support members within the longitudinal substrate cavity.

The layer of homogenized tobacco material is preferably in the form of a sheet. As used herein in connection with this disclosure, the term "sheet" describes a laminar element having a width and length substantially greater than its thickness.

The hollow tubular substrate element may have a length of at least about 5 millimeters, or at least about 7 millimeters, or at least about 10 millimeters.

The hollow tubular substrate element may have a length of up to about 30 millimeters, up to about 25 millimeters, or up to about 20 millimeters.

For example, the hollow tubular substrate element may have a length of about 5 millimeters to about 30 millimeters, or about 7 millimeters to about 25 millimeters, or about 10 millimeters to about 20 millimeters.

The hollow tubular base element preferably has a length of about 12 millimeters.

As mentioned above, the length of the hollow tubular substrate element may advantageously be matched to the longitudinal dimension of a heating element in a corresponding aerosol generating device used to heat the aerosol-generating article. In this way, as much of the aerosol-generating substrate as possible may be heated during use to optimize the amount of aerosol that can be produced and reduce the amount of tobacco waste.

Preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is at least about 0.1. More preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is at least about 0.15. More preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is at least about 0.2.

Preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article may be up to about 0.6. More preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article may be up to about 0.55. More preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article may be up to about 0.5.

For example, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article substrate may be from about 0.1 to about 0.6, more preferably from about 0.15 to about 0.55, and more preferably from about 0.2 to about 0.5.

Preferably, the hollow tubular substrate element has an outer diameter less than the outer diameter of the aerosol-generating article.

Preferably, the hollow tubular substrate element may have an outer diameter of at least about 5 millimeters, or at least about 5.5 millimeters, or at least about 6 millimeters.

Preferably, the hollow tubular substrate element may have an outer diameter of up to about 9 millimeters, or up to about 8 millimeters, or up to about 7.5 millimeters.

For example, the hollow tubular substrate element may have an outer diameter of about 5 millimeters to about 9 millimeters, or about 5.5 millimeters to about 8 millimeters, or about 6 millimeters to about 7.5 millimeters.

The outer diameter of the hollow tubular substrate element is preferably substantially constant along the length of the hollow tubular substrate. Alternatively, different portions of the hollow tubular substrate element may have different outer diameters.

The term "outer diameter" as used herein in connection with the present disclosure refers to the maximum diameter of the aerosol-generating article or component thereof in the transverse direction of the aerosol-generating article at a location along the length of the aerosol-generating article or component thereof. When a range or value of the outer diameter of the aerosol-generating article or component thereof is described herein, the outer diameter of the aerosol-generating article or component thereof along the entire length of the aerosol-generating article or component thereof may fall within the same range or have the same value. In other words, when a range or value of the outer diameter of the aerosol-generating article or component thereof is described herein, the outer diameter of the aerosol-generating article or component thereof at all locations along the length of the aerosol-generating article or component thereof may fall within the same range or have the same value.

The outer diameter of the hollow tubular substrate element does not include the width of any other components of the aerosol-generating substrate that are located outside the hollow tubular substrate element.

The hollow tubular substrate element has a peripheral wall that defines a longitudinal cavity or substrate cavity. The wall thickness of the hollow tubular substrate element may be selected based on the desired amount of tobacco material within the hollow tubular substrate. The wall thickness of the hollow tubular substrate element may also be selected to have a sufficiently high stiffness that the hollow tubular substrate element may be self-supporting. The wall thickness of the hollow tubular substrate may also be selected to have a cross-sectional area of the longitudinal cavity that provides the hollow tubular substrate element with a desired resistance to withdrawal (RTD).

The hollow tubular substrate element may have a wall thickness that is at least about 4 percent of the outer diameter of the hollow tubular substrate element, or at least about 5 percent of the outer diameter of the hollow tubular substrate element, or at least about 6 percent of the outer diameter of the hollow tubular substrate element.

The hollow tubular base element may have a wall thickness that is up to about 40 percent of the outer diameter of the hollow tubular base element, or up to about 30 percent of the outer diameter of the hollow tubular base element, or up to about 20 percent of the outer diameter of the hollow tubular base element.

For example, the hollow tubular substrate element may have a wall thickness that is about 4 percent to about 40 percent of the outer diameter of the hollow tubular substrate element, or about 5 percent to about 30 percent of the outer diameter of the hollow tubular substrate element, or about 6 percent to about 20 percent of the outer diameter of the hollow tubular substrate element.

The hollow tubular base element preferably has a wall thickness of about 7 percent of the outer diameter of the hollow tubular base element.

The hollow tubular substrate element may have a wall thickness of at least about 0.3 millimeters, or at least about 0.35 millimeters, or at least about 0.4 millimeters. The hollow tubular substrate element may have a wall thickness of at least 0.5 millimeters. The hollow tubular substrate element may have a wall thickness of at least 0.6 millimeters. The hollow tubular substrate element may have a wall thickness of at least 0.8 millimeters. The hollow tubular substrate element may have a wall thickness of at least about 1 millimeter.

The hollow tubular substrate element may have a wall thickness of up to about 3 millimeters, or up to about 2 millimeters, or up to about 1 millimeter.

For example, the hollow tubular substrate element may have a wall thickness of about 0.3 millimeters to about 3 millimeters, or about 0.35 millimeters to about 2 millimeters, or about 0.4 millimeters to about 1 millimeter.

The hollow tubular substrate element may have a wall thickness of about 0.5 millimeters to about 2 millimeters. The hollow tubular substrate element may have a wall thickness of about 1 millimeter to about 2 millimeters.

The hollow tubular substrate element may have a wall thickness of about 0.5 millimeters. The hollow tubular substrate element may have a wall thickness of about 1 millimeter.

As mentioned above, the longitudinal cavities provide an unrestricted flow channel through the hollow tubular base element. This means that the hollow tubular base element provides a negligible level of resistance to withdrawal (RTD). The term "negligible RTD" is used to describe an RTD of less than 1 mmH2O per 10 millimeters of the length of the hollow tubular base element, preferably less than 0.4 mmH2O per 10 millimeters of the length of the hollow tubular base element, and more preferably less than 0.1 mmH2O per 10 millimeters of the length of the hollow tubular base element.

The longitudinal cavity should therefore not contain any components that would impede longitudinal air flow. It is preferred that the longitudinal cavity is substantially empty. It is even more preferred that the longitudinal cavity is empty.

The longitudinal cavities may also be referred to as longitudinal airflow channels.

The longitudinal cavity extends between the ends of the hollow tubular substrate element and is preferably open at both the upstream and downstream ends. The open upstream end may provide a primary air inlet for drawing air through the aerosol-generating article when a consumer puffs on the article. The longitudinal cavity may thus provide a primary passageway for air and aerosol flow through the article.

The aerosol-generating substrate may have a length of at least about 10 millimeters, at least about 12 millimeters, or at least about 15 millimeters.

The aerosol-generating substrate may have a length of up to about 40 millimeters, up to about 37 millimeters, or up to about 35 millimeters.

For example, the aerosol-generating substrate may have a length of about 10 millimeters to about 40 millimeters, or about 12 millimeters to about 37 millimeters, or about 15 millimeters to about 35 millimeters.

The diameter of the longitudinal cavity corresponds to the inner diameter of the hollow tubular base element.

The longitudinal cavity may have a diameter of at least about 1 millimeter, or at least about 2 millimeters, or at least about 3 millimeters.

The longitudinal cavity may have a diameter of up to about 8 millimeters, or up to about 7 millimeters, or up to about 6.5 millimeters.

For example, the longitudinal cavity may have a diameter of about 1 millimeter to about 8 millimeters, or about 2 millimeters to about 7 millimeters, or about 3 millimeters to about 6.5 millimeters.

The longitudinal cavity may have a diameter of about 6 millimeters.

The longitudinal cavity diameter may be selected such that the cavity volume is large enough to provide the desired level of airflow while retaining sufficient wall thickness. This is necessary for the specification to provide a sufficient amount of tobacco material within the hollow tubular substrate element and to have a sufficiently high rigidity that the hollow tubular substrate element may be self-supporting.

The longitudinal cavities preferably have a substantially constant cross-sectional shape and size along the length of the hollow tubular substrate. However, one or both of the cross-sectional shape and size of the longitudinal cavities may vary along the length of the hollow tubular substrate element.

The longitudinal cavity preferably has a substantially circular transverse cross-section. Alternatively, the longitudinal cavity may have a substantially elliptical transverse cross-section.

The longitudinal cavity may have a constant diameter along the length of the hollow tubular substrate element. However, the diameter of the longitudinal cavity may vary along the length of the hollow tubular substrate element.

The central longitudinal axis of the hollow tubular substrate element is preferably aligned with the central longitudinal axis of other elements of the aerosol-generating article, e.g., other components of the aerosol-generating substrate and components of the downstream section. For example, the central longitudinal axis of the hollow tubular substrate element is preferably aligned with the central longitudinal axis of both the upstream and downstream components. The central longitudinal axis of the hollow tubular substrate element is preferably aligned with the central longitudinal axis of the aerosol-generating article.

The hollow tubular substrate element may include one or more susceptor elements positioned in contact with the peripheral wall for inductive heating of the homogenized tobacco material during use.

As used herein, the term "susceptor element" refers to an element that includes a material capable of converting electromagnetic energy into heat. When the susceptor element is located within an alternating electromagnetic field, the susceptor is heated. Heating of the susceptor element can 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.

The hollow tubular substrate element preferably comprises one or more susceptor elements on the surface of the peripheral wall. The hollow tubular substrate element may comprise one or more susceptor elements on the inner surface of the peripheral wall within the longitudinal airflow channel. Alternatively, or additionally, the hollow tubular substrate element may comprise one or more susceptor elements on the outer surface of the peripheral wall.

The susceptor elements may include any suitable material. The susceptor elements may be formed from 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 elements include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and composites of metallic materials. Some susceptor elements include metal or carbon. Advantageously, the susceptor elements may include or consist of ferromagnetic materials, such as ferritic iron, ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrites. Suitable susceptor elements may be or include aluminum. The susceptor elements preferably include more than about 5 percent, preferably more than about 20 percent, more preferably more than about 50 percent or more than about 90 percent ferromagnetic or paramagnetic material. Some elongated susceptor elements may be heated to temperatures greater than about 250 degrees Celsius.

An aerosol-generating article according to the present disclosure may further comprise an upstream section located upstream of the rod of the aerosol-generating substrate. The upstream section is preferably located immediately upstream of the rod of the aerosol-generating substrate. The upstream section preferably extends between the upstream end of the aerosol-generating article and the rod of the aerosol-generating substrate. The upstream section may comprise one or more upstream elements located upstream of the rod of the aerosol-generating substrate. Such one or more upstream elements are described in the present disclosure.

The aerosol-generating article of the present disclosure preferably comprises an upstream element located upstream of and adjacent to the aerosol-generating substrate. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-generating substrate.

Furthermore, the presence of the upstream element helps to prevent any loss of substrate, which may be advantageous, for example, when the substrate contains particulate plant material.

When the aerosol-generating substrate includes shredded tobacco, such as tobacco cut filler, the upstream section or elements thereof may additionally serve to prevent loss of loose tobacco particles from the upstream end of the article. This may be particularly important, for example, when the shredded tobacco has a relatively low density.

The upstream section or upstream element thereof may also provide at least some coverage to the upstream end of the aerosol-generating substrate that might otherwise be exposed, thereby providing some additional protection to the aerosol-generating substrate during storage.

In the case of an aerosol-generating article intended to be inserted into a cavity in an aerosol-generating device so that the aerosol-generating substrate can be externally heated within the cavity, advantageously the upstream section or element thereof may facilitate insertion of the upstream end of the article into the cavity. The inclusion of an upstream element may provide additional protection for the end of the rod of the aerosol-generating substrate during insertion of the article into the cavity, thereby minimizing the risk of damage to the substrate.

The upstream section or upstream elements thereof may also provide an improved appearance to the upstream end of the aerosol-generating article. Additionally, if desired, the upstream section or upstream elements thereof may be used to provide information about the aerosol-generating article, such as information about the brand, flavor, content, or details of the aerosol-generating device with which the aerosol-generating article is intended to be used.

The upstream element may be a porous plug element. The upstream element may be made of a porous material or may include a plurality of openings. This may be achieved, for example, by laser drilling. The plurality of openings is preferably uniformly distributed across the cross-section of the upstream element. The porosity or permeability of the upstream element may advantageously be designed to provide the aerosol-generating article with a particular overall resistance to withdrawal (RTD) without substantially affecting the filtration provided by other parts of the article.

The upstream element may be formed from a material that is impermeable to air. In such an embodiment, the aerosol-generating article may be configured to allow air to flow into the rod of the aerosol-generating substrate through suitable ventilation means provided in the wrapper.

The upstream element may be formed of a solid cylindrical plug element having a filled cross-section. Such a plug element may be referred to as a "plain" element. The solid plug element may be porous as described above, but does not have a tubular morphology and therefore does not provide a longitudinal flow channel. The solid plug element preferably has a substantially uniform cross-section.

The upstream element may be formed of a hollow tubular segment defining a longitudinal cavity that provides an unrestricted flow channel. Thus, the upstream element may provide protection to the aerosol-generating substrate as described above, while having a minimal effect on the overall resistance to draw (RTD) and filtration characteristics of the article.

Preferably, the longitudinal cavity diameter of the hollow tubular segment forming the upstream element is at least 3 millimeters, more preferably at least 3.5 millimeters, more preferably at least 4 millimeters, more preferably at least 4.5 millimeters. Preferably, the longitudinal cavity diameter is maximized to minimize the RTD of the upstream section or element thereof.

Preferably, the wall thickness of the hollow tubular segment is less than 2 millimeters, more preferably less than 1.5 millimeters, and more preferably less than 1 millimeter.

The upstream element of the upstream section may be made of any material suitable for use in an aerosol-generating article. The upstream element may be made of the same material as that used in one of the other components of the aerosol-generating article, such as, for example, a downstream filter segment or a hollow tubular cooling element. Suitable materials for forming the upstream element include filter material, ceramic, polymeric material, cellulose acetate, cardboard, zeolite, or an aerosol-generating substrate. The upstream element may include a plug of cellulose acetate. The upstream element may comprise a hollow acetate tube or a cardboard tube.

The upstream section or its upstream element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. Preferably, the outer diameter of the upstream section or its upstream element is between 5 millimeters and 8 millimeters, more preferably between 5.25 millimeters and 7.5 millimeters, more preferably between 5.5 millimeters and 7 millimeters.

Preferably, the upstream section or element has a length of 2 millimeters to 10 millimeters, more preferably 3 millimeters to 8 millimeters, more preferably 2 millimeters to 6 millimeters. In a particularly preferred embodiment, the upstream section or element has a length of 5 millimeters. The length of the upstream section or element may be advantageously varied to provide a desired overall length of the aerosol-generating article. For example, if it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream section or element may be increased to maintain the same overall length of the article.

In addition, for articles that are intended to be externally heated, the length of the upstream section or an upstream element thereof can be used to control the position of the aerosol-generating article within the cavity of the aerosol-generating device. This can advantageously ensure that the position of the aerosol-generating substrate within the cavity can be optimized for heating, and also the position of any ventilation can be optimized.

The upstream section is preferably surrounded by a wrapper such as plug wrap. The wrapper surrounding the upstream section is preferably a stiff plug wrap, for example a plug wrap having a basis weight of at least 80 grams per square meter (gsm), or at least 100 gsm, or at least 110 gsm. This provides structural rigidity to the upstream section.

The upstream section is preferably connected to the rod of the aerosol-generating substrate, and optionally to at least a portion of the downstream section, by an outer wrapper as described herein.

The upstream section may include a heat source, preferably a combustible heat source, and a thermally conductive element. The heat source may define an upstream end of the aerosol-generating article. The thermally conductive element may be located between and in direct contact with the heat source and the aerosol-generating substrate. The thermally conductive element may conduct heat from the heat source to the aerosol-generating substrate. The thermally conductive element may partially surround the aerosol-generating substrate. The thermally conductive element may partially surround the heat source. The heat source, the thermally conductive element, and the aerosol-generating substrate may be axially aligned in a continuous abutting manner. The aerosol-generating substrate, which is tubular, may include at least one perforation for providing an air inlet. The air inlet may provide fluid communication between the substrate cavity and the exterior of the aerosol-generating article. Suitable combustible heat sources for use with the aerosol-generating article are known in the art. The combustible heat source is preferably a combustible carbonaceous heat source. As used herein in connection with the present invention, the term "carbonaceous" is used to describe a combustible heat source that contains carbon.

Similar aerosol-generating articles having such an upstream section with a heat source and a thermally conductive element are further described in WO-A-2015/028654, WO-A-2015/022321, and WO-A-2009/022232.

As described above, the aerosol-generating article includes an airflow guiding element. The airflow guiding element extends longitudinally into a longitudinal substrate cavity. A primary airflow path or channel is defined between an outer surface of the airflow guiding element and an inner surface of the aerosol-generating substrate. Thus, a width or diameter of a portion of the airflow guiding element may be smaller than the diameter of the substrate cavity.

The airflow guiding element may extend into the substrate cavity from any position along the aerosol-generating article. Preferably, the airflow guiding element extends into the substrate cavity from a position upstream of the aerosol-generating substrate. The airflow guiding element may also extend into the substrate cavity from a position downstream of the aerosol-generating substrate.

As mentioned above, the aerosol-generating article may comprise an upstream section located upstream of the aerosol-generating substrate. The airflow guiding element may be coupled to or held by the upstream element adjacent the upstream end of the aerosol-generating substrate. The airflow guiding element may be coupled to or held by the downstream element adjacent the downstream end of the aerosol-generating substrate. The airflow guiding element coupled to or held by the upstream or downstream element allows the airflow guiding element to be supported by such upstream or downstream element instead of being supported by the aerosol-generating substrate itself. This may allow the airflow guiding element to extend into the cavity of the aerosol-generating substrate without having to rely on a manufacturing or assembly process that may involve rolling the aerosol-generating substrate or otherwise affecting the structural integrity of the substrate during the manufacturing or assembly process. This therefore allows for the extension of an airflow guiding element having a maximum width or diameter smaller than the inner diameter of the aerosol-generating substrate into the cavity of the aerosol-generating substrate without any internal contact between the airflow guiding element and the aerosol-generating substrate. In other words, the airflow guiding element may be effectively cantilevered and extend into the cavity of the substrate without the need for supporting wrapping or encircling the aerosol-generating substrate around the airflow guiding element or a portion thereof.

The aerosol-generating article may comprise a base support element from which the airflow guiding element may extend. The upstream section may include such a base support element. In other words, the base support element may be an upstream element. The base support element may be located upstream of the aerosol-generating substrate. The downstream end of the base support element may abut the upstream end of the aerosol-generating substrate. The outer diameter of the base support element may be approximately equal to the outer diameter of the aerosol-generating substrate.

The base support element may be located downstream of the aerosol-generating substrate such that the airflow guiding element may extend from a location downstream of the aerosol-generating substrate. Thus, the base support element may be a downstream element of the downstream section of the aerosol-generating article.

The base support element may be located within an upstream element located upstream of the aerosol-generating substrate. The base support element may be located within a downstream element located downstream of the aerosol-generating substrate. The base support element may be held or embedded within an upstream element located upstream of the aerosol-generating substrate. The base support element may be held or embedded within a downstream element located downstream of the aerosol-generating substrate. For example, the downstream or upstream element may include a hollow tubular element defining a longitudinal cavity, and the base support element may be sized to be held within such longitudinal cavity.

The base support element may have a disk or plate shape, and is preferably cylindrical. The base support element is preferably porous or includes at least one opening, which allows fluid communication to be established between the exterior of the aerosol-generating article and the interior of the aerosol-generating substrate through the base support element.

The airflow guiding element preferably includes an elongated body extending longitudinally into the base cavity. The airflow guiding element preferably includes an elongated body extending from an upstream end of the airflow guiding element to a downstream end of the airflow guiding element. The airflow guiding element preferably includes an elongated body extending from a fixed end of the airflow guiding element to a free end of the airflow guiding element.

When the base support element is located upstream of the aerosol-generating substrate, the upstream end of the airflow guiding element may be coupled to the base support element. When the base support element is located downstream of the aerosol-generating substrate, the downstream end of the airflow guiding element may be coupled to the base support element. The central longitudinal axis of the airflow guiding element may be aligned with the central longitudinal axis of the base support element. The airflow guiding element preferably comprises an elongate body extending from a fixed end of the airflow guiding element to a free end of the airflow guiding element. The end of the airflow guiding element coupled to the base support element may define the fixed end of the airflow guiding element and the opposing end may be the free end of the airflow guiding element.

The length of the base support element may be at least about 0.5 mm. The length of the base support element may be at least about 1 mm. The length of the base support element may be at least about 1.5 mm.

The length of the base support element may be up to about 5 mm. The length of the base support element may be up to about 4 mm. The length of the base support element may be up to about 3 mm.

The elongated body of the airflow guiding element may be rod-shaped or cone-shaped. The elongated body of the airflow guiding element preferably comprises a hollow body or tube defining an empty longitudinal cavity. The elongated body of the airflow guiding element preferably comprises a hollow cylindrical tube defining an empty longitudinal cavity.

The downstream end of the hollow body may be closed so that air cannot flow through the interior of the hollow body into the substrate cavity.

The airflow guiding element may include an airflow inlet at a first location and an airflow outlet at a second location downstream from the first location such that an airflow path is defined within and along the airflow guiding element.

The downstream end of the hollow body may be porous or may be provided with one or more perforations, openings, inlets, or outlets such that fluid communication is established between the interior of the hollow body and the substrate cavity, and a secondary airflow path into the substrate cavity is defined. The downstream end of the hollow body may be open such that fluid communication is established between the interior of the hollow body and the substrate cavity, and a secondary airflow path is defined within the airflow guiding element. The secondary airflow path may direct air directly to the downstream section of the article if the airflow guiding element spans the entire length of the substrate cavity. The secondary airflow path may direct air into the substrate cavity of the article if the airflow guiding element extends along less than 100 percent of the length of the substrate cavity.

The upstream end of the hollow body may also be open. The base support element is preferably porous or includes at least one opening such that fluid communication is established between the exterior of the aerosol-generating article and the interior of the aerosol-generating substrate through the base support element. The base support element may include a central opening aligned with the open upstream end of the airflow guiding element. This allows air to flow through the base support element into the substrate cavity via a central secondary airflow path defined within the airflow guiding element. A primary airflow path or channel may be defined between the inner surface of the aerosol-generating substrate and the outer surface of the airflow guiding element. In other words, the primary airflow path or channel may surround the airflow guiding element.

If the airflow guiding element comprises a hollow body, perforations or holes may be provided extending through the peripheral wall of the hollow body defining a longitudinal empty cavity. The peripheral wall of the hollow body may be porous. Such one or more peripheral perforations may follow a specific path along or around the hollow body of the airflow guiding element. Such one or more peripheral perforations may follow a linear, helical, curvilinear or wavy path along or around the hollow body of the airflow guiding element. This advantageously allows for fluid communication to be established between the interior of the hollow body and the base cavity such that one or more secondary airflow paths into the base cavity are defined. Air may enter the hollow body or tube of the airflow guiding element through the base support element and exit through the peripheral wall of the hollow body into the base cavity. Air moving through the hollow body may also exit into the base cavity through an opening at the downstream end of the hollow body. Such secondary airflows may provide dilution and cooling functions to the primary airflow moving downstream between the airflow guiding element and the inner surface of the aerosol generation element.

The width or diameter of the airflow guiding element may be uniform along its length. The width or diameter of the airflow guiding element may vary along its length. The inner diameter of the airflow guiding element may be at least about 0.5 mm. The inner diameter of the airflow guiding element may be at least about 1 mm. The inner diameter of the airflow guiding element may be at least about 1.5 mm. The inner diameter of the airflow guiding element may be at least about 2 mm. The inner diameter of the airflow guiding element may be up to about 5 mm. The inner diameter of the airflow guiding element may be up to about 4 mm. The size of the hollow cavity defined within the airflow guiding element defines the size of the secondary airflow channel or pathway and the amount of dilution or cooling air arranged to enter the substrate cavity during use.

The airflow guiding element may be textured. The airflow guiding element may have an uneven or raised outer surface. The airflow guiding element may include raised elements on its outer surface. The airflow guiding element may include one or more grooves, dimples, bumps, protrusions, or bulges provided on its outer surface. By having a textured or uneven outer surface, the airflow guiding element has the ability to disrupt the air flowing around it to form localized turbulence, which may enhance mixing of the air with the emitted aerosol-forming components.

The airflow guiding element may include a plurality or series of aligned segments that form an elongated body. Each of the segments may have any shape. Each of the segments may be pyramidal, rod-shaped, cylindrical, conical, circular, spherical, or hemispherical. For example, the airflow guiding element may include a plurality of aligned cone-shaped segments to form the elongated body.

The airflow guiding element may include an elongated core portion with an elongated body as described above and at least one extension portion located along the core portion. The at least one extension portion may include a hump, protrusion, or bulge provided on an outer surface of the core portion. The at least one extension portion may be formed on an outer surface of the core portion. The at least one extension portion may define a raised surface on the airflow guiding element, preferably on its core portion. The at least one extension portion may extend outwardly (in other words, away from the central axis of the core portion) from the core portion. The at least one extension portion may extend radially from the core portion. The at least one extension portion may extend longitudinally along the core portion. The at least one extension portion may extend circumferentially either completely or partially around the core portion.

The airflow guiding element may include at least two extensions located along the core portion. Each extension may be located at a respective longitudinal or axial position along the core portion. The airflow guiding element may include three extensions located along the core portion.

The extensions may be substantially shaped in the form of a sphere, hemisphere, cylinder, or ring. By providing one or more extensions along a core portion of the airflow guiding element, the width or diameter of the airflow guiding element may vary along its length to promote localized airflow separation from the outer surface of the airflow guiding element. This in turn may promote localized turbulent airflows to form between the airflow guiding element and the inner surface of the aerosol-generating substrate, thereby improving aerosol generation as a result of enhanced mixing of air with the aerosol-forming components emitted from the heated aerosol-generating substrate.

Each extension of the airflow guiding element may extend a certain length along the core portion. The length of each of the airflow guiding elements or extensions may be at least about 5 percent of the total length of the airflow guiding element. The length of each of the airflow guiding elements or extensions may be at least about 10 percent of the total length of the airflow guiding element. The length of each of the airflow guiding elements or extensions may be at least about 15 percent of the total length of the airflow guiding element. The length of each of the airflow guiding elements or extensions may be at least about 20 percent of the total length of the airflow guiding element. The length of each of the airflow guiding elements or extensions may be at least about 25 percent of the total length of the airflow guiding element.

The length of each of the airflow guiding elements or extensions may be up to about 75 percent of the total length of the airflow guiding element. The length of each of the airflow guiding elements or extensions may be up to about 60 percent of the total length of the airflow guiding element. The length of each of the airflow guiding elements or extensions may be up to about 50 percent of the total length of the airflow guiding element. The length of each of the airflow guiding elements or extensions may be up to about 40 percent of the total length of the airflow guiding element. The length of each of the airflow guiding elements or extensions may be up to about 35 percent of the total length of the airflow guiding element.

When multiple extensions are provided, each extension may have a different length. For example, the airflow guiding element may include three extensions arranged sequentially along the core portion, with the first extension extending along about 15 percent of the total length of the airflow guiding element and the other two extensions extending along about 35 percent of the total length of the airflow guiding element.

Advantageously, the amount of turbulence and turbulence created in the air flowing around the air flow guiding element can be adjusted depending on the size of the extension portion relative to the air flow guiding element, the position of the or each extension portion along the air flow guiding element, and the distance between successive or adjacent extension portions.

The extension portion may be provided at an upstream end of the airflow guiding element or its core portion. The extension portion may be provided at a downstream end of the airflow guiding element or its core portion.

Successive or adjacent extension portions may be spaced apart from one another to define a gap therebetween. The extension portions may be evenly spaced apart from one another. Providing a gap between successive or adjacent extension portions defines a section of the primary airflow channel of increasing cross-sectional area, which allows for localized deceleration of the air after flowing over the upstream extension portion or before flowing over the downstream extension portion, primarily when the cross-section of the extension portion is uniform along its length, such as a cylinder or ring. The outer surface of the core portion may be exposed by such a gap.

The base support element and the airflow guiding element may be manufactured separately and then bonded to each other before assembly of the aerosol generating article. The base support element and the airflow guiding element may be integrally formed with each other, for example by extrusion or by injection molding. Similarly, the core portion and any extension portion of the airflow guiding element may be manufactured separately and then bonded to each other before assembly of the aerosol generating article. The core portion and any extension portion of the airflow guiding element may be integrally formed with each other, for example by extrusion or by injection molding. The extension portion may be manufactured separately from the core portion and then assembled on the core portion. For example, the extension portion may be a ring-shaped or cylindrical-shaped element that is mounted on and bonded to the core portion. For example, such a ring-shaped or cylindrical-shaped element may be slid onto the core portion and bonded to the core portion by gluing or an interference fit.

The material of the base support element and the material of the airflow guiding element may be the same. The airflow guiding element, the base support element, or both may be formed from a non-metallic material. The airflow guiding element, the base support element, or both may be free of metallic materials. The airflow guiding element, the base support element, or both may be formed from cardboard. The airflow guiding element, the base support element, or both may be formed from a paper-based material. The airflow guiding element, the base support element, or both may be formed from paper. The airflow guiding element, the base support element, or both may be formed from a polymeric material. The airflow guiding element, the base support element, or both may be formed from a plastic material. The airflow guiding element, the base support element, or both may be formed from a bioplastic material. The airflow guiding element, the base support element, or both may be formed from cellulose acetate. The materials referred to in this disclosure may provide base support elements and airflow guidance elements that can be cost-effectively manufactured while offering suitable resistance to deformation or compression.

The airflow guiding element, the base support element, or both may include a thermally conductive material. This may facilitate heat transfer to the inner surface of the aerosol-generating substrate, especially when heated by an external heating element.

The airflow guiding element may include an outer layer or coating at least partially provided on an outer surface, preferably the outer surface of the airflow guiding element body. The outer layer or coating may include one or more of an aerosol former, a flavorant, and a further aerosol-generating substrate. Such aerosol formers, flavorants, and further aerosol-generating substrates of the outer layer or coating may be in accordance with the aerosol formers, flavorants, and aerosol-generating substrates, respectively, described in this disclosure.

The length of the airflow guiding element preferably corresponds to the amount that the airflow guiding element extends into the base cavity.

The length of the airflow guiding element may be at least about 1 mm. The length of the airflow guiding element may be at least about 3 mm. The length of the airflow guiding element may be at least about 5 mm. The length of the airflow guiding element may be at least about 6 mm. The length of the airflow guiding element may be at least about 8 mm. The length of the airflow guiding element may be at least about 9 mm.

The length of the airflow guide element may be up to about 30 mm. The length of the airflow guide element may be up to about 25 mm. The length of the airflow guide element may be up to about 20 mm. The length of the airflow guide element may be up to about 15 mm. The length of the airflow guide element may be up to about 12 mm. The length of the airflow guide element may be up to about 10 mm.

The length of the airflow guide element may be about 1 mm to about 30 mm, about 3 mm to about 30 mm, about 5 mm to about 30 mm, about 6 mm to about 30 mm, about 8 mm to about 30 mm, or preferably about 9 mm to about 30 mm. The length of the airflow guide element may be about 1 mm to about 25 mm, about 3 mm to about 25 mm, about 5 mm to about 25 mm, about 6 mm to about 25 mm, about 8 mm to about 25 mm, or preferably about 9 mm to about 25 mm. The length of the airflow guide element may be about 1 mm to about 20 mm, about 3 mm to about 20 mm, about 5 mm to about 20 mm, about 6 mm to about 20 mm, about 8 mm to about 20 mm, or preferably about 9 mm to about 20 mm. The length of the airflow guiding element may be about 1 mm to about 15 mm, about 3 mm to about 15 mm, about 5 mm to about 15 mm, about 6 mm to about 15 mm, about 8 mm to about 15 mm, or preferably about 9 mm to about 15 mm. The length of the airflow guiding element may be about 1 mm to about 12 mm, about 3 mm to about 12 mm, about 5 mm to about 12 mm, about 6 mm to about 12 mm, about 8 mm to about 12 mm, or preferably about 9 mm to about 12 mm. The length of the airflow guiding element may be about 1 mm to about 10 mm, about 3 mm to about 10 mm, about 5 mm to about 10 mm, about 6 mm to about 10 mm, about 8 mm to about 10 mm, or preferably about 9 mm to about 10 mm.

The length of the airflow guiding element may be at least about 10 percent of the length of the aerosol-generating substrate or substrate cavity. The length of the airflow guiding element may be at least about 25 percent of the length of the aerosol-generating substrate or substrate cavity. The length of the airflow guiding element may be at least about 30 percent of the length of the aerosol-generating substrate or substrate cavity. The length of the airflow guiding element may be at least about 50 percent of the length of the aerosol-generating substrate or substrate cavity. The length of the airflow guiding element may be at least about 60 percent of the length of the aerosol-generating substrate or substrate cavity. The length of the airflow guiding element may be at least about 75 percent of the length of the aerosol-generating substrate or substrate cavity. The length of the airflow guiding element may be at least about 80 percent of the length of the aerosol-generating substrate or substrate cavity. The length of the airflow guiding element may be at least about 90 percent of the length of the aerosol-generating substrate or substrate cavity. The length of the airflow guiding element may be at least about 100 percent of the length of the aerosol-generating substrate or substrate cavity.

The length of the airflow guiding element defines the length of the restricted airflow path or channel defined between the outer surface of the airflow guiding element and the inner surface of the aerosol-generating substrate. It may be realized that a balance can be struck between providing a relatively long airflow guiding element to define a relatively long restricted airflow path and the manufacturing costs of providing such a long airflow guiding element. Ideally, the length of the airflow guiding element may be at least about 50 percent, and preferably at least about 60 percent, of the length of the aerosol-generating substrate or substrate cavity.

The central or longitudinal axis of the airflow guiding element is preferably aligned with the central or longitudinal axis of the aerosol-generating substrate. The airflow guiding element is preferably axially symmetric. This may ensure that the restricted airflow channel defined around the airflow guiding element and between the airflow guiding element and the inner surface of the aerosol-generating substrate is axially symmetric.

The airflow guiding element has a maximum outer diameter. One or more raised surfaces or extensions of the airflow guiding element may define the maximum outer diameter or width of the airflow guiding element. Thus, the diameter or width of the airflow guiding element may vary or oscillate along the length of the airflow guiding element.

The maximum outer diameter or width of the airflow guiding element may be at least about 1 mm. The maximum outer diameter or width of the airflow guiding element may be at least about 2 mm. The maximum outer diameter or width of the airflow guiding element may be at least about 2.5 mm. The maximum outer diameter or width of the airflow guiding element may be at least about 3 mm.

The maximum outer diameter or width of the airflow guiding element may be at least about 8 mm. The maximum outer diameter or width of the airflow guiding element may be at least about 7.5 mm. The maximum outer diameter or width of the airflow guiding element may be at least about 7 mm. The maximum outer diameter or width of the airflow guiding element may be at least about 6 mm.

The maximum outer diameter or width of the airflow guiding element may be about 1 mm to about 8 mm, about 2 mm to about 8 mm, about 2.5 mm to about 8 mm, or preferably about 3 mm to about 8 mm. The maximum outer diameter or width of the airflow guiding element may be about 1 mm to about 7.5 mm, about 2 mm to about 7.5 mm, about 2.5 mm to about 7.5 mm, or preferably about 3 mm to about 7.5 mm. The maximum outer diameter or width of the airflow guiding element may be about 1 mm to about 7 mm, about 2 mm to about 7 mm, about 2.5 mm to about 7 mm, or preferably about 3 mm to about 7 mm. The maximum outer diameter or width of the airflow guiding element may be about 1 mm to about 6 mm, about 2 mm to about 6 mm, about 2.5 mm to about 6 mm, or preferably about 3 mm to about 6 mm.

The maximum outer diameter or width of the airflow guiding element may be at least about 25 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity. The maximum outer diameter or width of the airflow guiding element may be at least about 40 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity. The maximum outer diameter or width of the airflow guiding element may be at least about 50 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity. The maximum outer diameter or width of the airflow guiding element may be at least about 60 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity. The maximum outer diameter or width of the airflow guiding element may be at least about 75 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity.

A portion of the airflow guiding element having a diameter corresponding to the maximum outer diameter or width of the airflow guiding element may be located away from (or downstream of) the base or upstream end of the airflow guiding element. A portion of the airflow guiding element having a diameter corresponding to the maximum outer diameter or width of the airflow guiding element may be located at least about 10 percent of the length of the airflow guiding element away from (or downstream of) the base or upstream end of the airflow guiding element. A portion of the airflow guiding element having a diameter corresponding to the maximum outer diameter or width of the airflow guiding element may be located at least about 20 percent of the length of the airflow guiding element away from (or downstream of) the base or upstream end of the airflow guiding element. A portion of the airflow guiding element having a diameter corresponding to the maximum outer diameter or width of the airflow guiding element may be located at least about 25 percent of the length of the airflow guiding element away from (or downstream of) the base or upstream end of the airflow guiding element. The portion of the air flow guiding element having a diameter corresponding to the maximum outer diameter or width of the air flow guiding element may be located at least about 50 percent of the length of the air flow guiding element away from (or downstream of) the base or upstream end of the air flow guiding element.

The diameter of a portion of the air flow guiding element upstream of a portion of the air flow guiding element having a diameter corresponding to the maximum outer diameter or width of the air flow guiding element, or any diameter, is preferably less than (or does not exceed) the maximum outer diameter or width of the air flow guiding element.

The airflow guiding element may have a minimum outer diameter. For an airflow guiding element having a uniform outer diameter or width, the diameter or width of the airflow guiding element may correspond to the maximum outer diameter or width, or the minimum outer diameter or width. A core portion of the airflow guiding element may define the minimum outer diameter or width of the airflow guiding element.

The minimum outer diameter or width of the airflow guiding element may be at least about 0.5 mm. The minimum outer diameter or width of the airflow guiding element may be at least about 1.5 mm. The minimum outer diameter or width of the airflow guiding element may be at least about 2.5 mm. The minimum outer diameter or width of the airflow guiding element may be at least about 3 mm.

The minimum outer diameter or width of the airflow guiding element may be at least about 8 mm. The minimum outer diameter or width of the airflow guiding element may be at least about 7.5 mm. The minimum outer diameter or width of the airflow guiding element may be at least about 7 mm. The minimum outer diameter or width of the airflow guiding element may be at least about 6 mm.

The minimum outer diameter or width of the airflow guiding element may be about 0.5 mm to about 8 mm, about 1.5 mm to about 8 mm, about 2.5 mm to about 8 mm, or preferably about 3 mm to about 8 mm. The minimum outer diameter or width of the airflow guiding element may be about 0.5 mm to about 7.5 mm, about 1.5 mm to about 7.5 mm, about 2.5 mm to about 7.5 mm, or preferably about 3 mm to about 7.5 mm. The minimum outer diameter or width of the airflow guiding element may be about 0.5 mm to about 7 mm, about 1.5 mm to about 7 mm, about 2.5 mm to about 7 mm, or preferably about 3 mm to about 7 mm. The minimum outer diameter or width of the airflow guiding element may be about 1 mm to about 6 mm, about 2 mm to about 6 mm, about 2.5 mm to about 6 mm, or preferably about 3 mm to about 6 mm.

The minimum outer diameter or width of the airflow guiding element may be at least about 10 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity. The minimum outer diameter or width of the airflow guiding element may be at least about 20 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity. The minimum outer diameter or width of the airflow guiding element may be at least about 25 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity. The minimum outer diameter or width of the airflow guiding element may be at least about 40 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity. The minimum outer diameter or width of the airflow guiding element may be at least about 50 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity. The minimum outer diameter or width of the airflow guiding element may be at least about 60 percent of the inner diameter of the aerosol-generating substrate or the diameter of the substrate cavity.

The maximum outer diameter or width of the airflow guiding element may be about 100 percent of the inner diameter of the aerosol-generating substrate, or the diameter of the substrate cavity. Thus, a portion of the airflow guiding element may contact the aerosol-generating substrate. A portion of an extended or raised portion of the airflow guiding element may contact the aerosol-generating substrate. Sizing the airflow guiding element to contact the aerosol-generating substrate may facilitate centering the airflow guiding element with the substrate cavity and may also assist in retaining the airflow guiding element within the substrate cavity.

The airflow guiding element may extend along a central axis of the substrate cavity. A longitudinal gap or space may be defined between an outer surface of the airflow guiding element and an inner peripheral surface of the aerosol-generating substrate. The outer surface of the airflow guiding element, or a portion thereof, may be spaced from an inner surface of the substrate cavity such that an airflow channel is defined between the outer surface of the airflow guiding element and the inner surface of the aerosol-generating substrate. Preferably, such a defined airflow channel may be referred to as a primary airflow channel or a restricted airflow channel.

The airflow channel is preferably annular in shape. In other words, the gap or space between the airflow guiding element and the inner surface of the aerosol-generating substrate may define a substantially annular chamber or channel.

The distance between the outer surface of the airflow guiding element and the inner surface of the aerosol-generating substrate may define the height or thickness of the primary or restricted airflow channel. Depending on the local diameter or width of the airflow guiding element at a particular longitudinal and circumferential location along its elongated body, the height or thickness of the airflow channel may vary longitudinally or circumferentially, or both.

The maximum thickness of the airflow channel may be at least about 0.25 mm. The maximum thickness of the airflow channel may be at least about 0.5 mm. The maximum thickness of the airflow channel may be at least about 1 mm. The maximum thickness of the airflow channel may be at least about 1.5 mm.

The minimum thickness of the airflow channel may be at least about 0 mm. In other words, a portion of the airflow guiding element may contact the aerosol-generating substrate such that there is no distance or gap between such portion of the airflow guiding element and the aerosol-generating substrate. The minimum thickness of the airflow channel may be at least about 0.25 mm. The minimum thickness of the airflow channel may be at least about 0.5 mm. The minimum thickness of the airflow channel may be at least about 1.5 mm. The airflow guiding element may not contact the inner surface of the aerosol-generating substrate. Along its entire length, the airflow guiding element may not contact the inner surface of the aerosol-generating substrate. In other words, no part of the outer surface of the airflow guiding element contacts the inner surface of the aerosol-generating substrate. This allows for the definition of an airflow channel that is thicker and more unobstructed, thereby allowing more airflow to travel between the inner surface of the aerosol-generating substrate and the airflow guiding element.

The maximum thickness of the airflow channel may be up to about 6 mm. The maximum thickness of the airflow channel may be up to about 5 mm. The maximum thickness of the airflow channel may be up to about 3 mm. The maximum thickness of the airflow channel may be up to about 2.5 mm.

The minimum thickness of the airflow channel may be up to about 6 mm. The minimum thickness of the airflow channel may be up to about 5 mm. The minimum thickness of the airflow channel may be up to about 3 mm. The minimum thickness of the airflow channel may be up to about 2.5 mm.

For an airflow guiding element having a substantially uniform diameter or width along its length, the thickness or height of the airflow channel may be uniform such that the minimum and maximum thicknesses of the airflow channel are effectively equivalent.

In the aerosol-generating article of the present disclosure, an aerosol-generating substrate comprising a hollow tubular substrate element is combined with a downstream section located downstream of the aerosol-generating substrate. The downstream section is preferably located immediately downstream of the aerosol-generating substrate. The downstream section of the aerosol-generating article preferably extends between the aerosol-generating substrate and the downstream end of the aerosol-generating article. The downstream section may comprise one or more elements, each of which is described in more detail within this disclosure.

The downstream section preferably comprises at least one hollow tubular element. The hollow tubular element may be adjacent to the downstream end of the rod of the aerosol-generating substrate. The hollow tubular element may be located immediately downstream of the aerosol-generating substrate. In other words, the hollow tubular element may abut the downstream end of the aerosol-generating substrate. This arrangement may optimize the flow of aerosol from the longitudinal airflow channel of the hollow tubular substrate element into the downstream section and through the aerosol-generating article.

The downstream section of the aerosol-generating article preferably comprises a single hollow tubular element. In other words, the downstream section of the aerosol-generating article may comprise only one hollow tubular element.

The hollow tubular elements of the downstream section may also be referred to as hollow tubular downstream elements.

In the context of this disclosure, the hollow tubular elements of the downstream section provide an unrestricted flow channel through the airflow passage. This means that the hollow tubular elements provide a negligible level of resistance to draw (RTD), as defined above. Thus, the airflow passage should not include any components that would impede the longitudinal air flow. Preferably, the airflow passage is substantially empty.

The hollow tubular element of the downstream section provides an empty cavity downstream of the aerosol-generating substrate, which may improve cooling and nucleation of the aerosol particles generated by the aerosol-generating substrate. The hollow tubular element of the downstream section may therefore function as an aerosol cooling element.

The length of the hollow tubular element may be at least about 12 mm. The length of the hollow tubular element may be at least about 15 mm. The length of the hollow tubular element may be at least about 20 mm.

The length of the hollow tubular element in the downstream section may be about 50 mm or less. The length of the hollow tubular element may be about 45 mm or less. The length of the hollow tubular element may be about 40 mm or less.

For example, the length of the hollow tubular element in the downstream section may be about 12 mm to 50 mm. The length of the hollow tubular element may be about 15 mm to 45 mm. The length of the hollow tubular element may be about 20 mm to about 40 mm. The length of the hollow tubular element may be about 30 mm.

The relatively long hollow tubular element provides and defines a relatively long internal cavity within the downstream section of the aerosol-generating article. Providing a relatively long cavity maximizes the nucleation benefits discussed above, which may improve aerosol formation and cooling.

The ratio of the length of the hollow tubular base element to the length of the hollow tubular element in the downstream section may be about 1.25 or less. Preferably, the ratio of the length of the hollow tubular base element to the length of the hollow tubular element in the downstream section may be about 1 or less. More preferably, the ratio of the length of the hollow tubular base element to the length of the hollow tubular element in the downstream section may be about 0.75 or less.

The ratio of the length of the hollow tubular base element to the length of the hollow tubular element in the downstream section may be at least about 0.2. Preferably, the ratio of the length of the hollow tubular base element to the length of the hollow tubular element in the downstream section may be at least about 0.25. More preferably, the ratio of the length of the hollow tubular base element to the length of the hollow tubular element in the downstream section may be at least about 0.3.

For example, the ratio of the length of the hollow tubular substrate element to the length of the hollow tubular element in the downstream section may be from about 0.2 to about 1.25, or from about 0.25 to about 1, or from about 0.3 to about 0.75.

The ratio of the length of the hollow tubular element in the downstream section to the total length of the downstream section may be about 1 or less. Preferably, the ratio of the length of the hollow tubular element in the downstream section to the total length of the downstream section may be about 0.90 or less. More preferably, the ratio of the length of the hollow tubular element in the downstream section to the total length of the downstream section may be about 0.85 or less.

The ratio of the length of the hollow tubular element in the downstream section to the total length of the downstream section may be at least about 0.35. Preferably, the ratio of the length of the hollow tubular element in the downstream section to the total length of the downstream section may be at least about 0.45. More preferably, the ratio of the length of the hollow tubular element in the downstream section to the total length of the downstream section may be at least about 0.50.

For example, the ratio of the length of the hollow tubular element in the downstream section to the overall length of the downstream section may be from about 0.35 to about 1, or from about 0.45 to about 0.9, or from about 0.5 to about 0.85.

The ratio of the length of the hollow tubular element in the downstream section to the overall length of the aerosol-generating article may be about 0.80 or less. Preferably, the ratio of the length of the hollow tubular element in the downstream section to the overall length of the aerosol-generating article may be about 0.70 or less. More preferably, the ratio of the length of the hollow tubular element in the downstream section to the overall length of the aerosol-generating article may be about 0.60 or less.

The ratio of the length of the hollow tubular element in the downstream section to the overall length of the aerosol-generating article may be at least about 0.25. Preferably, the ratio of the length of the hollow tubular element in the downstream section to the overall length of the aerosol-generating article may be at least about 0.30. More preferably, the ratio of the length of the hollow tubular element in the downstream section to the overall length of the aerosol-generating article may be at least about 0.40.

For example, the ratio of the length of the hollow tubular element in the downstream section to the overall length of the aerosol-generating article may be from about 0.25 to about 0.8, or from about 0.3 to about 0.7, or from about 0.4 to about 0.6.

The wall thickness of the hollow tubular element in the downstream section may be at least about 100 micrometers. The wall thickness of the hollow tubular element in the downstream section may be at least about 150 micrometers. The wall thickness of the hollow tubular element in the downstream section may be at least about 200 micrometers, preferably at least about 250 micrometers, and even more preferably at least about 500 micrometers (or 0.5 mm).

The wall thickness of the hollow tubular element in the downstream section may be about 2 millimeters or less, preferably about 1.5 millimeters or less, and even more preferably about 1.25 mm or less. The wall thickness of the hollow tubular element in the downstream section may be about 1 millimeter or less. The wall thickness of the hollow tubular element in the downstream section may be about 500 micrometers or less.

The wall thickness of the hollow tubular element in the downstream section can be from about 100 micrometers to about 2 millimeters, preferably from about 150 micrometers to about 1.5 millimeters, and even more preferably from about 200 micrometers to about 1.25 millimeters.

By keeping the wall thickness of the hollow tubular segment of the downstream section relatively small, it is ensured that the overall internal volume of the hollow tubular element (which is made available for the aerosol to initiate the nucleation process as soon as the aerosol components leave the aerosol-generating substrate) and the cross-sectional surface area of the hollow tubular element cavity are effectively maximized, while at the same time ensuring that the hollow tubular element has the necessary structural strength to provide some support to the rod of the aerosol-generating substrate as well as to prevent the collapse of the aerosol-generating article, and that the RTD of the hollow tubular element is minimized. It is understood that a larger value of the cross-sectional surface area of the hollow tubular element cavity is associated with a reduced speed of the aerosol flow along the aerosol-generating article, which is also expected to favor the nucleation of the aerosol. Furthermore, by utilizing a hollow tubular element having a relatively small thickness, it may be expected that the diffusion of the vent air can be substantially prevented before it contacts and mixes with the aerosol flow, which is also understood to be more favorable for the nucleation phenomenon. Indeed, by providing more controllably localized cooling of the stream of volatilized species, it may be possible to enhance the cooling effect on the formation of new aerosol particles.

The hollow tubular element of the downstream section preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating substrate and the outer diameter of the aerosol-generating article. The hollow tubular element of the downstream section preferably has an outer diameter greater than the outer diameter of the hollow tubular substrate element of the aerosol-generating substrate.

The hollow tubular element may have an outer diameter of 5 millimeters to 10 millimeters, for example, 5.5 millimeters to 9 millimeters, or 6 millimeters to 8 millimeters.

The hollow tubular element in the downstream section may have a constant inner diameter along the length of the hollow tubular element. However, the inner diameter of the hollow tubular element may vary along the length of the hollow tubular element.

The hollow tubular element of the downstream section may have an inner diameter of at least about 2 millimeters. For example, the hollow tubular element may have an inner diameter of at least about 2.5 millimeters, at least about 3 millimeters, or at least about 3.5 millimeters. Providing a hollow tubular element with an inner diameter as presented above may advantageously provide the hollow tubular element with sufficient stiffness and strength.

The hollow tubular element of the downstream section may have an inner diameter of about 10 millimeters or less. For example, the hollow tubular element may have an inner diameter of about 9 millimeters or less, about 8 millimeters or less, or about 7.5 millimeters or less. By providing a hollow tubular element having such an inner diameter, the resistance to withdrawal of the hollow tubular segment may be advantageously reduced.

For example, the hollow tubular element of the downstream section may have an inner diameter of about 2 millimeters to about 10 millimeters, about 2.5 millimeters to about 9 millimeters, about 3 millimeters to about 8 millimeters, or about 3.5 millimeters to about 7.5 millimeters.

The ratio of the inner diameter of the hollow tubular base element to the inner diameter of the hollow tubular element in the downstream section is preferably about 0.8 to about 1.2, more preferably about 0.9 to about 1.1, and most preferably about 1.

Particularly preferably, the inner diameter of the hollow tubular base element is substantially equal to the inner diameter of the hollow tubular element of the downstream section.

The central longitudinal axis of the hollow tubular substrate element of the aerosol-generating substrate may preferably be aligned with the central longitudinal axis of the hollow tubular substrate element of the downstream section. For example, if the inner diameter of the hollow tubular substrate element is substantially equal to the inner diameter of the hollow tubular substrate element of the downstream section, the central longitudinal axis of the hollow tubular substrate element may be aligned with the central longitudinal axis of the hollow tubular substrate element of the downstream section such that the cavity of the hollow tubular substrate element and the cavity of the hollow tubular substrate element of the downstream section may be substantially aligned.

The hollow tubular element of the downstream section may comprise a paper-based material. The hollow tubular element may comprise at least one layer of paper. The paper may be a very stiff paper. The paper may be a crimped paper, such as crimped heat-resistant paper or crimped parchment paper.

Preferably, the hollow tubular element may include cardboard. The hollow tubular element may be a cardboard tube. The hollow tubular element may be formed from cardboard. Advantageously, cardboard is a cost-effective material that provides a balance between being deformable to provide ease of insertion of the aerosol-generating article into the aerosol generating device, and being sufficiently rigid to provide suitable engagement of the article with the interior of the device. Thus, a cardboard tube may provide adequate resistance to deformation or compression during use.

The hollow tubular element of the downstream section may be a paper tube. The hollow tubular element may be a tube formed from spirally wound paper. The hollow tubular element may be formed from multiple layers of paper. The paper may have a basis weight of about 50 grams per square meter, at least about 60 grams per square meter, at least about 70 grams per square meter, or at least about 90 grams per square meter.

The hollow tubular elements of the downstream section may comprise a polymeric material. For example, the hollow tubular elements may comprise a polymeric film. The polymeric film may comprise a cellulose film. The hollow tubular segments may comprise low density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tubular elements may comprise cellulose acetate tow.

When the hollow tubular element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of about 2 to about 4 and a total denier of about 25 to about 40.

The hollow tubular element may be at the upstream end of the downstream section. The hollow tubular element may abut the downstream end of the aerosol-generating substrate. The hollow tubular element may abut the downstream end of the hollow tubular substrate element.

Aerosol-generating articles according to the present disclosure may include a ventilation zone at a location along the downstream section. More specifically, when the downstream section includes a hollow tubular element, a ventilation zone may be provided at a location along the hollow tubular element.

In this way, a ventilated cavity is provided downstream of the rod of the aerosol-generating substrate. This provides a particularly efficient cooling of the aerosol and can promote improved nucleation of the aerosol particles.

The ventilation zone may typically include a plurality of perforations through the circumferential wall of the hollow tubular element. The plurality of perforations in the ventilation zone may also pass through a wrapper surrounding the hollow tubular element. The ventilation zone preferably comprises at least one circumferential row of perforations. The ventilation zone may also include two circumferential rows of perforations. For example, the perforations may be formed on-line during manufacture of the aerosol-generating article. Preferably, each circumferential row of perforations includes between 8 and 30 perforations.

The downstream section may further comprise a mouthpiece element. The mouthpiece element may be located at the downstream end of the aerosol-generating article. The mouthpiece element is preferably located downstream of the hollow tubular element of the downstream section, as described above. The mouthpiece element may extend between the hollow tubular element of the downstream section and the downstream end of the aerosol-generating article.

Providing a mouthpiece element at the downstream end of an aerosol generating article according to the present disclosure can provide an appealing appearance and mouthfeel to the consumer.

The mouthpiece element may be a mouthpiece filter element. The mouthpiece element may comprise at least one mouthpiece filter segment formed of a fibrous filtration material. Parameters or characteristics described with respect to the mouthpiece element as a whole may be equally applicable to the mouthpiece filter segment of the mouthpiece element.

The fibrous filtration material may be for filtering the aerosol generated from the aerosol-generating substrate. Suitable fibrous filtration materials will be known to those skilled in the art. Particularly preferably, at least one of the mouthpiece filter segments comprises a cellulose acetate filter segment formed from cellulose acetate tow.

The mouthpiece element may be comprised of a single mouthpiece filter segment. The mouthpiece element may include two or more mouthpiece filter segments abutting and axially aligned in end-to-end relationship with one another.

The downstream section may comprise a mouth end cavity at a downstream end downstream of the mouthpiece element as described above. The mouth end cavity may be defined by a further hollow tubular element provided at the downstream end of the mouthpiece element. The mouth end cavity may be defined by an outer wrapper of the aerosol-generating article, the outer wrapper extending in a downstream direction from (or past) the mouthpiece element. For example, the mouth end cavity may be defined by a tipping wrapper extending downstream beyond the mouthpiece element.

The mouthpiece element may optionally include a flavorant, which may be provided in any suitable form. For example, the mouthpiece element may include one or more capsules, beads or granules of flavorant, or one or more flavor-loaded threads or filaments.

Preferably, the mouthpiece element, or its mouthpiece filter segment, has low particle filtration efficiency.

Preferably, the mouthpiece element is surrounded by a plug wrap. Preferably, the mouthpiece element is non-ventilated so that air does not enter the aerosol-generating article along the mouthpiece element.

The mouthpiece element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The diameter of the mouthpiece element (or mouthpiece filter segment) may be substantially the same as the outer diameter of the hollow tubular element. As discussed in this disclosure, the outer diameter of the hollow tubular element may be approximately 7.2 mm plus or minus 10 percent.

The diameter of the mouthpiece element may be about 5 mm to about 10 mm. The diameter of the mouthpiece element may be about 5.5 mm to about 9 mm. The diameter of the mouthpiece element may be about 6 mm to about 8 mm. The diameter of the mouthpiece element may be about 7.2 mm ± 10 percent. The diameter of the mouthpiece element may be about 7.25 mm ± 10 percent.

Unless otherwise specified, 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 entire length of the component. The terms "pressure drop" or "draw resistance" of a component or article can also refer to "resistance to draw."

The resistance to withdrawal (RTD) of the downstream section may be at least about 0 mmH2O. The RTD of the downstream section may be at least about 3 mmH2O. The RTD of the downstream section may be at least about 6 mmH2O.

The RTD of the downstream section may be about 12 mmH2O or less. The RTD of the downstream section may be about 11 mmH2O or less. The RTD of the downstream section may be about 10 mmH2O or less.

The resistance to withdrawal in the downstream section may be about 0 mmH2O or more and less than about 12 mmH2O. Preferably, the resistance to withdrawal in the downstream section may be about 3 mmH2O or more and less than about 12 mmH2O. The resistance to withdrawal in the downstream section may be about 0 mmH2O or more and less than about 11 mmH2O. Even more preferably, the resistance to withdrawal in the downstream section may be about 3 mmH2O or more and less than about 11 mmH2O. Even more preferably, the resistance to withdrawal in the downstream section may be about 6 mmH2O or more and less than about 10 mmH2O. Preferably, the resistance to withdrawal in the downstream section may be about 8 mmH2O.

The resistance to draw (RTD) characteristics of the downstream section may be due in whole or in large part to the RTD characteristics of the mouthpiece element of the downstream section. In other words, the RTD of the mouthpiece element of the downstream section may completely dictate the RTD of the downstream section.

The resistance to draw (RTD) of the mouthpiece element may be at least about 0 mmH2O. The RTD of the mouthpiece element may be at least about 3 mmH2O. The RTD of the mouthpiece element may be at least about 6 mmH2O.

The RTD of the mouthpiece element may be about 12 mmH2O or less. The RTD of the mouthpiece element may be about 11 mmH2O or less. The RTD of the mouthpiece element may be about 10 mmH2O or less.

The resistance to withdrawal of the mouthpiece element may be about 0 mmH2O or more and less than about 12 mmH2O. Preferably, the resistance to withdrawal of the mouthpiece element may be about 3 mmH2O or more and less than about 12 mmH2O. The resistance to withdrawal of the mouthpiece element may be about 0 mmH2O or more and less than about 11 mmH2O. Even more preferably, the resistance to withdrawal of the mouthpiece element may be about 3 mmH2O or more and less than about 11 mmH2O. Even more preferably, the resistance to withdrawal of the mouthpiece element may be about 6 mmH2O or more and less than about 10 mmH2O. Preferably, the resistance to withdrawal of the mouthpiece element may be about 8 mmH2O.

As discussed above, the mouthpiece element or mouthpiece filter segment may be formed of a fibrous material. The mouthpiece element may be formed of a porous material. The mouthpiece element may be formed of a biodegradable material. The mouthpiece element may be formed of a cellulosic material, such as cellulose acetate. For example, the mouthpiece element may be formed from a bundle of cellulose acetate fibers having about 10 to about 15 denier per filament. For example, the mouthpiece element may be formed from a relatively low density cellulose acetate tow, such as cellulose acetate tow containing about 12 denier fibers per filament.

The mouthpiece element may be formed of a polylactic acid based material. The mouthpiece element may be formed of a bioplastic material, preferably a starch based bioplastic material. The mouthpiece element may be made by injection molding or extrusion. Bioplastic based materials are advantageous because they can provide a simple and inexpensive mouthpiece element structure to manufacture with specific and complex cross-sectional profiles that may include multiple relatively large airflow channels extending through the material of the mouthpiece element that provide suitable RTD characteristics.

The mouthpiece elements may be formed from sheets of suitable material that are crimped, pleated, assembled, woven, or folded into elements that define a plurality of longitudinally extending channels. Such sheets of suitable material may be formed of paper, cardboard, polymers such as polylactic acid, or any other cellulosic, paper-based, or bioplastic-based material. The cross-sectional profile of such mouthpiece elements may exhibit randomly oriented channels.

The mouthpiece element may be formed in any other suitable manner. For example, the mouthpiece element may be formed from a bundle of longitudinally extending tubes. The longitudinally extending tubes may be formed from polylactic acid. The mouthpiece element may be formed by extrusion, molding, lamination, injection molding, or shredding of a suitable material. Therefore, it is preferred that there is a low pressure drop (or RTD) from the upstream end of the mouthpiece element to the downstream end of the mouthpiece element.

The length of the mouthpiece element may be at least about 1.5 mm. The length of the mouthpiece element may be at least about 2 mm. The length of the mouthpiece element may be about 7 mm or less. The length of the mouthpiece element may be about 4 mm or less. For example, the length of the mouthpiece element may be from about 1.5 mm to about 7 mm. The length of the mouthpiece element may be from about 2 mm to about 4 mm.

The ratio of the length of the mouthpiece element to the length of the downstream section may be about 0.35 or less. Preferably, the ratio of the length of the mouthpiece element to the length of the downstream section may be about 0.30 or less. More preferably, the ratio of the length of the mouthpiece element to the length of the downstream section may be about 0.25 or less.

The ratio of the length of the mouthpiece element to the length of the downstream section may be at least about 0.03. Preferably, the ratio of the length of the mouthpiece element to the length of the downstream section may be at least about 0.05. More preferably, the ratio of the length of the mouthpiece element to the length of the downstream section may be at least about 0.1.

For example, the ratio of the length of the mouthpiece element to the length of the downstream section is about 0.03 to about 0.35, preferably about 0.05 to about 0.30, and more preferably about 0.1 to about 0.25.

The ratio of the length of the mouthpiece element to the overall length of the aerosol-generating article may be about 0.20 or less. Preferably, the ratio of the length of the mouthpiece element to the overall length of the aerosol-generating article may be about 0.15 or less. More preferably, the ratio of the length of the mouthpiece element to the overall length of the aerosol-generating article may be about 0.1 or less.

The ratio of the length of the mouthpiece element to the overall length of the aerosol-generating article may be at least about 0.01. Preferably, the ratio of the length of the mouthpiece element to the overall length of the aerosol-generating article may be at least about 0.02. More preferably, the ratio of the length of the mouthpiece element to the overall length of the aerosol-generating article may be at least about 0.05.

For example, the ratio of the length of the mouthpiece element to the overall length of the aerosol-generating article is from about 0.01 to about 0.2, preferably from about 0.02 to about 0.15, and more preferably from about 0.05 to about 0.1.

When the downstream section comprises a hollow tubular element and a mouthpiece element, the ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 1.5. In other words, the length of the hollow tubular element may be at least about 150% of the length of the mouthpiece. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 5. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 7.5.

The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be about 20 or less. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be about 15 or less. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be about 12.5 or less.

For example, the ratio of the length of the hollow tubular element to the length of the mouthpiece element can be from about 1.5 to about 20, or from about 5 to about 15, or from about 7.5 to about 10.

The total length of the downstream section is preferably at least about 15 millimeters, more preferably at least about 20 millimeters, and more preferably at least about 25 millimeters.

The overall length of the downstream section is preferably less than about 50 millimeters, more preferably less than about 45 millimeters, and more preferably less than about 40 millimeters.

For example, the downstream section may have an overall length of about 20 millimeters to about 50 millimeters, more preferably about 25 millimeters to about 45 millimeters, and more preferably about 30 millimeters to about 40 millimeters.

The ratio of the length of the downstream section to the overall length of the aerosol-generating article may be about 0.80 or less. Preferably, the ratio of the length of the downstream section to the overall length of the aerosol-generating article may be about 0.75 or less. More preferably, the ratio of the length of the downstream section to the overall length of the aerosol-generating article may be about 0.70 or less. Even more preferably, the ratio of the length of the downstream section to the overall length of the aerosol-generating article may be about 0.65 or less.

The ratio of the length of the downstream section to the overall length of the aerosol-generating article may be at least about 0.30. Preferably, the ratio of the length of the downstream section to the overall length of the aerosol-generating article may be at least about 0.40. More preferably, the ratio of the length of the downstream section to the overall length of the aerosol-generating article may be at least about 0.50. Even more preferably, the ratio of the length of the downstream section to the overall length of the aerosol-generating article may be at least about 0.60.

Preferably, the overall length of an aerosol-generating article according to the present invention is at least about 35 millimeters. More preferably, the overall length of an aerosol-generating article according to the present invention is at least about 40 millimeters. Even more preferably, the overall length of an aerosol-generating article according to the present invention is at least about 45 millimeters. Even more preferably, the overall length of an aerosol-generating article according to the present invention is at least about 50 millimeters.

The overall length of the aerosol-generating article according to the present invention is preferably 110 mm or less. More preferably, the overall length of the aerosol-generating article according to the present invention is preferably 100 mm or less. Even more preferably, the overall length of the aerosol-generating article according to the present invention is preferably 75 mm or less. Even more preferably, the overall length of the aerosol-generating article according to the present invention is preferably 70 mm or less.

For example, the overall length of the aerosol-generating article may be from about 35 millimeters to about 110 millimeters, or from about 40 millimeters to about 100 millimeters, or from about 45 millimeters to about 75 millimeters, or from about 50 millimeters to about 70 millimeters.

The aerosol-generating article preferably has an outer diameter of at least about 5 millimeters. Preferably, the aerosol-generating article has an outer diameter of at least 5.5 millimeters. More preferably, the aerosol-generating article has an outer diameter of at least 6 millimeters.

The aerosol-generating article preferably has an outer diameter of about 10 millimeters or less. More preferably, the aerosol-generating article has an outer diameter of about 9 millimeters or less. Even more preferably, the aerosol-generating article has an outer diameter of about 8 millimeters or less.

For example, the aerosol-generating article may have an outer diameter of about 5 millimeters to about 10 millimeters, or about 5.5 millimeters to about 9 millimeters, or about 6 millimeters to about 8 millimeters.

The outer diameter of the aerosol-generating article may be substantially constant along the entire length of the article. Alternatively, different portions of the aerosol-generating article may have different outer diameters.

One or more of the components of the aerosol-generating article may be individually enclosed by their own wrapper.

The aerosol-generating substrate and downstream section are preferably combined with a wrapper, such as a tipping wrapper.

The components of the aerosol-generating article according to the present disclosure are preferably made from biodegradable materials.

Preferably, the aerosol generating article according to the disclosure described herein is adapted for use in an electrically operated aerosol generating system in which the aerosol-generating substrate of the heated aerosol-generating article is heated by an electrical heat source. As described herein, an electrically operated aerosol generating system comprising an inductive heating device may also comprise an aerosol-generating article having an aerosol-generating substrate and a susceptor in thermal proximity to the aerosol-generating substrate. The susceptor may be in direct contact with the aerosol-generating substrate, and heat is transferred from the susceptor to the aerosol-generating substrate primarily by conduction. Examples of electrically operated aerosol generating systems comprising an inductive heating device and an aerosol-generating article having a susceptor are described in WO-A1-95/27411 and WO-A1-2015/177255.

The present disclosure relates to an aerosol generating system comprising an aerosol generating device having a distal end and an oral end. The aerosol generating device may comprise a body or housing. The body or housing of the aerosol generating device may define a device cavity or heating chamber for removably receiving an aerosol-generating article at the oral end of the device. The aerosol generating device may comprise a heating element or heater for heating the aerosol-generating substrate when the aerosol-generating article is received within the device cavity.

In other words, the aerosol generating device may comprise a heating chamber for receiving the aerosol generating article and a heating element provided at or around the periphery of the heating chamber.

The device cavity may be referred to as the heating chamber of the aerosol generating device. The device cavity may extend between a distal end and an oral (or proximal) end. The distal end of the device cavity may be a closed end and the oral (or proximal) end of the device cavity may be an open end. The oral or open end of the device cavity may correspond to the oral or distal end of the aerosol generating device. The aerosol generating device may be configured to receive an aerosol generating article through the oral end of the device or device cavity (or heating chamber). The aerosol generating device may be configured to receive an aerosol generating article through the oral end of the device or device cavity (or heating chamber). The device cavity or heating chamber may be configured to receive an aerosol generating article through or through its oral end. The aerosol generating article may be configured to be received in the device or device cavity (or heating chamber) or in the device or device cavity through or through the oral end of the device or device cavity. The aerosol-generating article may be configured to be inserted into the device or device cavity (or heating chamber) via or through the mouth end of the device or device cavity. The aerosol-generating article may be inserted into the device cavity or heating chamber via the open end of the device or device cavity. The device cavity may be cylindrical in shape to fit the same shape of the aerosol-generating article.

The phrase "received within" may refer to the fact that a component or element is fully or partially received within another component or element. For example, the phrase "an aerosol-generating article is received within a device cavity" refers to the aerosol-generating article being fully or partially received within the device cavity of the aerosol-generating article. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may abut a distal end of the device cavity. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may be substantially proximate to a distal end of the device cavity. The distal end of the device cavity may be defined by an end wall.

When received within the device or device cavity (or heating chamber), the aerosol-generating article may be configured to protrude or extend beyond the mouth end of the aerosol-generating device. The length of the aerosol-generating article may be longer than the length of the device cavity (or heating chamber). This allows for easier insertion and removal of the article from the device, and allows for a portion of the mouth end of the article to extend beyond the device from which the user can draw aerosol.

The length of the device cavity may be from about 15 millimeters to about 80 millimeters. Preferably, the length of the device cavity is from about 20 millimeters to about 70 millimeters. More preferably, the length of the device cavity is from about 25 millimeters to about 60 millimeters. More preferably, the length of the device is from about 25 millimeters to about 50 millimeters.

The length of the device cavity may be about 25 millimeters to about 29 millimeters. Preferably, the length of the device cavity is about 25 millimeters to about 29 millimeters. More preferably, the length of the device cavity is about 26 millimeters to about 29 millimeters. Even more preferably, the length of the device cavity is about 27 millimeters or about 28 millimeters.

The diameter of the device cavity may be from about 4 millimeters to about 10 millimeters. The diameter of the device cavity may be from about 5 millimeters to about 9 millimeters. The diameter of the device cavity may be from about 6 millimeters to about 8 millimeters. The diameter of the device cavity may be from about 6 millimeters to about 7.5 millimeters.

The diameter of the device cavity may be substantially the same as the diameter of the aerosol-generating article, or may be larger. The diameter of the device cavity may be the same as the diameter of the aerosol-generating article to establish a tight fit with the aerosol-generating article.

The device cavity may be configured to establish a tight fit with an aerosol-generating article received within the device cavity. A tight fit may refer to a sliding fit. The aerosol-generating device may include a peripheral wall. Such a peripheral wall may define the device cavity, or the heating chamber. The peripheral wall defining the device cavity may be configured to engage in a tight fit with an aerosol-generating article received within the device cavity such that, when received within the device, there is substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article.

Such an airtight fit may establish an airtight fit or configuration between the device cavity and the aerosol-generating article received therein. In such an airtight configuration, there will be substantially no gaps or empty spaces between the peripheral walls defining the device cavity and the aerosol-generating article for air to flow through. The tight fit with the aerosol-generating article may be established along the entire length of the device cavity or along a portion of the length of the device cavity.

The aerosol generating device may include an air intake channel extending between the channel inlet and the channel outlet. The air intake channel may be configured to establish fluid communication between an interior of the device cavity and an exterior of the aerosol generating device. The air intake channel of the aerosol generating device may be defined within a housing of the aerosol generating device to enable fluid communication between an interior of the device cavity and an exterior of the aerosol generating device. When an aerosol generating article is received within the device cavity, the air intake channel may be configured to provide air flowing into the article for delivery of generated aerosol to a user who draws from a mouth end of the article.

The air intake 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 air intake 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 air intake channel may be partially defined by the inner surface of the peripheral wall, or partially defined within the thickness of the peripheral wall. The inner surface of the peripheral wall defines the periphery of the device cavity.

The air intake channel of the aerosol generating device may extend from an inlet located at the mouth end or proximal end of the aerosol generating device to an outlet located away from the mouth end of the device. The air intake channel may extend along a direction parallel to the longitudinal axis of the aerosol generating device.

The heating chamber or device cavity may be sized to provide a longitudinal gap between the aerosol-generating article received therein and the peripheral walls defining the device cavity. Such longitudinal gap may partially or completely surround the aerosol-generating article received within the device. Such longitudinal gap or space may define an air intake channel extending from the open mouth end of the device cavity to the closed distal end of the device cavity. Additionally, the device housing may be configured such that air may enter the upstream end of the article when the upstream end of the article abuts the distal end of the device cavity. The device housing and cavity may be such that fluid communication is established between the air intake channel of the device and the upstream end of the received aerosol-generating article, preferably at the distal end of the device cavity. As a result, when an inserted aerosol-generating article is inhaled, air may enter the aerosol-generating device through the air intake channel, flow toward the distal end of the device cavity, and enter the upstream end of the received article.

The heater may be any suitable type of heater. In the present disclosure, it is preferred that the heater is an external heater.

The heating element of such an aerosol-generating device may be in any suitable form for conducting heat. Heating of the aerosol-generating substrate may be accomplished internally, externally, or both. The heating element may be a heater blade or pin adapted to be inserted into the aerosol-generating substrate such that the substrate is heated from the inside. Preferably, the heating element partially or completely surrounds the substrate and may externally heat the substrate circumferentially from the outside.

Preferably, the heater may externally heat the aerosol-generating article when received within the aerosol-generating device. Such an external heater may surround the aerosol-generating article when inserted or received within the aerosol-generating device. Preferably, the length of the heater substantially corresponds to the length of the aerosol-generating substrate of the aerosol-generating article that the aerosol-generating device is configured to receive.

The heater may be arranged to heat the outer surface of the aerosol-generating substrate. The heater may be arranged for insertion into the aerosol-generating substrate when the aerosol-generating substrate is received within the cavity. The heater may be located within the device cavity or heating chamber.

The heater may comprise at least one heating element. The at least one heating element may be any suitable type of heating element. The device may comprise only one heating element. The device comprises multiple heating elements. The heater may comprise at least one resistive heating element. The heater preferably comprises multiple resistive heating elements. The resistive heating elements are preferably electrically connected in a parallel arrangement. Advantageously, providing multiple resistive heating elements electrically connected in a parallel arrangement may facilitate delivery of desired power to the 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.

The heater may include an induction heating arrangement. The induction heating arrangement includes an induction source and a susceptor, which may be provided external to the aerosol-generating substrate or internal to the aerosol-generating substrate. The induction source may include an inductor coil and a power source configured to provide a high-frequency oscillating current to the inductor coil. As used herein, high-frequency oscillating current means an oscillating current having a frequency of about 500 kHz to about 30 MHz. The heater may advantageously include a DC/AC inverter for converting a DC current provided by a DC power source to an alternating current. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field upon receiving the high-frequency oscillating current from the power source. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field within the device cavity. The inductor coil may substantially surround the device cavity. The inductor coil may extend at least partially along the length of the device cavity.

The heater may include an induction heating element. The induction heating element may be a susceptor element. As used herein, the term "susceptor element" refers to an element that includes a material capable of converting electromagnetic energy into heat. When the susceptor element is located within an alternating electromagnetic field, the susceptor is heated. 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.

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

The susceptor element may be located in contact with the aerosol-generating substrate. The susceptor element may be located within the aerosol-generating device. The susceptor element may be located at or around the periphery of the device cavity. The aerosol-generating device may include only one susceptor element. The aerosol-generating device may comprise multiple susceptor elements. The susceptor element is preferably arranged to provide external heating to the aerosol-generating substrate. The susceptor element may surround the aerosol-generating article when contained within the heating chamber.

The susceptor elements may include any suitable material. The susceptor elements may be formed from 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 elements include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and composites of metallic materials. Some susceptor elements include metal or carbon. Advantageously, the susceptor elements may include or consist of ferromagnetic materials, such as ferritic iron, ferromagnetic steel or stainless steel, ferromagnetic alloys, ferromagnetic particles, and ferrites. A suitable susceptor element may be or include aluminum. The susceptor elements preferably include more than about 5 percent ferromagnetic or paramagnetic material, preferably more than 20 percent ferromagnetic or paramagnetic material, and more preferably more than 50 percent or more than 90 percent ferromagnetic or paramagnetic material. Some elongated susceptor elements can be heated to temperatures in excess of 250 degrees Celsius.

The susceptor element may include a non-metallic core having a metallic layer disposed thereon. For example, the susceptor element may include a ceramic core or a metallic track formed on the outer surface of the substrate.

The aerosol generating device may include at least one resistive heating element and at least one inductive heating element. The aerosol generating device may include a combination of a resistive heating element and an inductive heating element.

In use, the heater can be controlled to operate within a defined operating temperature range that is less than the maximum operating temperature. The operating temperature range within the heating chamber (or device cavity) is preferably from about 150 degrees Celsius to about 300 degrees Celsius. The operating temperature range of the heater may be from about 150 degrees Celsius to about 250 degrees Celsius.

Preferably, the operating temperature range of the heater may be between about 150 degrees Celsius and about 200 degrees Celsius. More preferably, the operating temperature range of the heater may be between about 180 degrees Celsius and about 200 degrees Celsius. Specifically, as described in this disclosure, it has been found that optimal and consistent aerosol delivery can be achieved when using an aerosol generating device having an external heater with an operating temperature range of about 180 degrees Celsius to about 200 degrees Celsius, with an aerosol-generating article having a relatively low RTD ( _e.g. , having an RTD of the downstream section of less than 15 millimeters H2O).

As mentioned above, the hollow tubular substrate element of an aerosol-generating article according to the present disclosure may advantageously be adapted such that its length substantially matches the longitudinal dimension of the heating element of the aerosol generating system that is intended to be used to heat the aerosol-generating article. This ensures that the hollow tubular substrate element is heated along substantially its entire length, so that aerosol generation from the aerosol-generating substrate may be maximized.

The aerosol generating device may include a power source. The power source may be a DC power source. In some embodiments, the power source is a battery. The power source may be a nickel metal hydride battery, a nickel cadmium battery, or a lithium-based battery (e.g., lithium cobalt, lithium iron phosphate, or lithium polymer battery). However, in some embodiments, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging and may have a capacity that allows for the storage of sufficient energy for one or more user operations, such as one or more aerosol generating experiences. For example, the power source may have a capacity sufficient to allow continuous heating of the aerosol-generating substrate for approximately six minutes, or a multiple of six minutes, corresponding to the typical time it takes to smoke a conventional cigarette. In another embodiment, the power source may have a capacity sufficient to allow for a predetermined number of puffs, or for discontinuous activation of the heater.

1 comprises a rod of aerosol-generating substrate 12 and a downstream section 14 provided downstream of the rod of aerosol-generating substrate 12. The aerosol-generating article 1 extends from an upstream or distal end 16 coinciding with the upstream end of the aerosol-generating substrate 12 to a downstream or mouth end 18 coinciding with the downstream end of the downstream section 14. The downstream section 14 may include one or more components, such as a hollow tubular element or a mouthpiece element, as described within this disclosure.

The aerosol-generating article 1 has an outer diameter of approximately 7.25 mm.

The aerosol-generating substrate 12 includes a hollow tubular substrate element 40 formed of homogenized tobacco material. The hollow tubular substrate element 40 has a peripheral wall 42 that defines a longitudinal cavity 44 that provides an unrestricted flow channel through the hollow tubular substrate element 40. The upstream end of the longitudinal cavity 44 provides an air inlet through which air may be drawn into the aerosol-generating article 10 during use. The hollow tubular substrate element 40 has a length of about 12 millimeters and an outer diameter of about 7.25 mm. The wall thickness of the hollow tubular substrate element 40 is about 1 mm and the diameter of the substrate cavity 44 is 5.25 mm.

Each of the components of the aerosol-generating article shown in the figures and described in this disclosure may be surrounded by a corresponding wrapper or may be joined together by one or more wrappers not shown in the figures.

The aerosol-generating article 1 further comprises an airflow guiding element 20 extending from an upstream location into the longitudinal substrate cavity 44. The airflow guiding element 20 comprises an elongated body in the form of a hollow tube having a uniform outer diameter and a closed downstream end. The length of the airflow guiding element 20 is about 10 mm. The outer diameter of the airflow guiding element 20 is about 3 mm. The airflow guiding element 20 is made from or comprises cardboard.

The aerosol-generating article 1 also includes an upstream section 30 provided upstream of the aerosol-generating substrate 12. In the aerosol-generating article 1, the upstream section 30 includes a base support element 32. The base support element 32 has the same outer diameter as the aerosol-generating substrate 12. The downstream end of the base support element 32 abuts the upstream end of the aerosol-generating substrate 12. The upstream end 16 is defined by the upstream end of the base support element 32. The base support element 32 includes a porous material, such as cellulose acetate, to allow fluid communication between the exterior of the aerosol-generating article 1 and the substrate cavity 44.

The airflow guiding element 20 is coupled to the base support element 32 and extends downstream therefrom. Thus, the upstream end of the airflow guiding element 20 is coupled to the base support element 32, while the downstream end of the airflow guiding element 20 defines a free end, as shown in FIG. 1. The length of the base support element is approximately 1 mm.

The annular airflow channel 22 is defined between the inner surface of the hollow aerosol-generating substrate 12 and the outer surface of the airflow guiding element 20. As a user draws on the mouth end 18 of the aerosol-generating article 1, air may be drawn through the base support element 32 via the upstream end 16. The air may then flow through the annular airflow channel 22 and proceed toward the downstream end 18 of the article 1.

Figure 2 shows a cross-section of the aerosol-generating article 1 at a location between the upstream and downstream ends of the airflow guiding element 20. The wall thickness of the hollow tubular substrate element 40 is about 1 mm. The thickness of the annular airflow channel 22 is about 1.13 mm.

Figure 3 illustrates another embodiment of the aerosol-generating article 1 in which the downstream end of the airflow guiding element 20 is open. This defines a secondary airflow channel 24 that extends from the upstream end to the downstream end of the airflow guiding element. Air can flow through the porous base support element 32, enter the empty longitudinal cavity defined by the hollow tube of the airflow guiding element 20, and exit through its open downstream end. The inner diameter of the airflow guiding element 20 shown in Figure 3 is about 1.5 mm. The inner diameter of the airflow guiding element 20 shown in Figure 3 defines the diameter of the secondary airflow channel 24. The airflow guiding element 20 is made of or includes cardboard.

Figure 4 shows another embodiment of an aerosol-generating article 2. The aerosol-generating article 2 differs from the aerosol-generating article 1 shown in Figure 1 in that the base support element 32 is held within a cavity of a hollow upstream element 34 and the airflow guiding element 201 has a different configuration. The upstream section 30 includes an upstream element 34 in the form of a hollow tubular element defining an empty longitudinal cavity extending along its entire length. The upstream element 34 abuts the aerosol-generating substrate 12.

The outer diameter of the base support element 32 is sized so that the base support element 32 is retained within the upstream element 34. In other words, the base support element 32 establishes a tight fit with the inner wall of the upstream element 34. The base support element 34 spans transversely across the entire cavity defined by the upstream element 34. The downstream end of the base support element 32 is aligned with the upstream end of the upstream element 34. The length of the base support element 32 is about 1.5 mm. The length of the hollow upstream element 34 is about 5 mm. In the embodiment of FIG. 4, the outer and inner diameters of the upstream element 34 are the same as the outer and inner diameters of the aerosol generation element 12 located immediately downstream.

The airflow guiding element 201 includes an irregular outer surface such that the outer diameter of the airflow guiding element 201 varies along its length. An annular airflow channel 22 is similarly defined around the airflow guiding element 201. The airflow guiding element 201 includes an elongated core portion 21 and a plurality of extension portions 23 extending radially outward from the elongated core portion 21. The airflow guiding element 201 includes two extension portions 23, a first extension portion 23 positioned at a downstream free end of the airflow guiding element 201 and a second extension portion 23 positioned immediately upstream of the first extension portion 23. The extension portions 23 are spherical in shape. The airflow guiding element 201 is made of or includes cardboard.

The length of the airflow guide element 201 is about 8 mm. The maximum outer diameter or width of the airflow guide element 201 is about 3 mm. The minimum outer diameter or width of the airflow guide element 201 is about 1 mm. The maximum thickness of the airflow channel 22 is about 1.13 mm, and the minimum thickness of the airflow channel 22 is about 2.13 mm.

5 shows another embodiment of the aerosol-generating article 3. The aerosol-generating article 3 differs from the aerosol-generating article 1 shown in FIG. 1 in that the airflow guiding element 202 has a different configuration. The airflow guiding element 202 includes an irregular outer surface such that the outer diameter of the airflow guiding element 202 varies along its length and an annular airflow channel 22 is defined around the airflow guiding element 202. The airflow guiding element 202 includes an elongated core portion 21 and a plurality of extension portions 231, 232 extending radially outward from the elongated core portion 21. The airflow guiding element 202 includes three extension portions 231, 232. The first extension portion 231 is located at the upstream fixed end of the airflow guiding element 202 and is hemispherical in shape. The upstream end of the first extension portion 231 is flat and is coupled to the downstream end of the base support element 32. As shown in FIG. 5, downstream of the first extension portion 231 are two successively arranged spherical extension portions 232. One of the extension portions 232 is located at the downstream free end of the air flow guiding element 202, and the other is located immediately upstream thereof, between the extension portion 232 and the other extension portion 231.

The airflow guiding element 202 is made of or includes cardboard.

The length of the airflow guide element 202 is about 8 mm. The maximum outer diameter or width of the airflow guide element 202 is about 3 mm. The minimum outer diameter or width of the airflow guide element 202 is about 1 mm. The maximum thickness of the airflow channel 22 is about 1.13 mm, and the minimum thickness of the airflow channel 22 is about 2.13 mm.

6 shows another embodiment of the aerosol-generating article 4. The aerosol-generating article 4 differs from the aerosol-generating article 1 shown in FIG. 1 in that the airflow guiding element 203 has a different configuration. The airflow guiding element 203 includes an irregular outer surface such that the outer diameter of the airflow guiding element 203 varies along its length. The airflow guiding element 203 includes a core portion 213 and a plurality of extension portions 233 extending radially outward from the core portion 213. The airflow guiding element 203 includes four extension portions 233. The four extension portions 234 are cylindrically shaped protrusions evenly spaced along the core portion 213. In this embodiment, the most upstream and downstream extension portions 233 are spaced apart from the upstream and downstream ends of the airflow guiding element 203, respectively.

The airflow guiding element 203 is made of or includes cardboard.

The length of the airflow guide element 203 is about 8 mm. The maximum outer diameter or width of the airflow guide element 203 is about 3 mm. The minimum outer diameter or width of the airflow guide element 203 is about 1 mm. The maximum thickness of the airflow channel 22 is about 1.13 mm, and the minimum thickness of the airflow channel 22 is about 2.13 mm.

Figure 7 illustrates an aerosol generating system 10 including an exemplary aerosol generating device 100 configured to receive any one of the aerosol generating articles described in this disclosure. In Figure 7, the aerosol generating article is the aerosol generating article 2 shown in Figure 4.

7 illustrates a downstream mouth end portion of an aerosol generating device 100 in which a device cavity (or heating chamber) is defined and in which an aerosol generating article can be received. The aerosol generating device 100 comprises a housing (or body) 104 extending between a mouth end 102 and a distal end (not shown). The housing 104 includes a peripheral wall 106. The peripheral wall 106 defines a device cavity for receiving an aerosol generating article 2. The device cavity is defined by a closed distal end and an open mouth end. The mouth end of the device cavity is located at the mouth end of the aerosol generating device 100. The aerosol generating article 2 is configured to be received through the mouth end of the device cavity and held within the device cavity. The aerosol generating device 100 is configured such that during use, air enters the device cavity, passes through its upstream end 16 into the device cavity and into the aerosol generating article.

The aerosol generating device 100 further comprises a heater 110 and a power supply (not shown) for supplying power to the heater. A controller (not shown) is also provided for controlling the supply of such power to the heater. The heater 110 is configured to controllably heat the aerosol generating article 2 during use when the aerosol generating article 2 is received within the device 100. The heater 110 is arranged to externally heat the aerosol generating substrate 12 of the aerosol generating article 2 during use.

8 illustrates an aerosol-generating article 5 that differs from the aerosol-generating article 3 shown in FIG. 5 in that it is not configured to be inserted into a separate heating device and heated. Instead, the upstream section 30 of the aerosol-generating article 4 includes a combustible heat source 34 and a thermally conductive element 36 located between and in direct contact with the heat source 34 and the aerosol-generating substrate 36. The heat source 34 defines the upstream end 16 of the aerosol-generating article 5. The aerosol-generating substrate 12 includes at least one perforation 46 for providing an air inlet in the substrate cavity 44. In use, the combustible heat source 34 is ignited and air can be drawn into the substrate cavity 44 through the air inlet provided by the perforation 46 and drawn downstream toward the mouth end 18 of the article 5. Heat is configured to be transferred from the heat source 4 to the aerosol-generating substrate 12 by conduction through the thermally conductive element 36. Furthermore, the thermally conductive element 36 acts as a base support element for the airflow guiding element 202. In other words, the upstream end of the airflow guiding element 202 is coupled to the downstream end or downstream surface of the thermally conductive element 36.

The thermally conductive element 36 includes a thermally conductive wall 361 located between the heat source 34 and the aerosol-generating substrate 36 and two sleeve portions 362, 363. The upstream sleeve portion 362 extends upstream from the periphery of the thermally conductive wall 361 and is arranged to hold a downstream or proximal portion of the heat source 34 in contact with the thermally conductive wall 361. The downstream sleeve portion 363 extends downstream from the periphery of the thermally conductive wall 361 and is arranged to hold an upstream or distal portion of the aerosol-generating substrate 12 in contact with the thermally conductive wall 361. The aerosol-generating article 5 includes an airflow guiding element 204 that is the same shape and size as the airflow guiding element 202 of the aerosol-generating article 4. Instead of or in addition to cardboard, the airflow guiding element 204 may include a thermally conductive material such as aluminum. Both the thermally conductive wall 361 and the airflow guiding element 204 may include the same thermally conductive material.

In all figures of this disclosure, airflow paths, aerosol flow paths, or other fluid paths into and through the aerosol-generating article during use are indicated by discontinuous arrows.

For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like are understood to be modified in all instances by the term "about." Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A±10%. Within this context, the number A may be considered to include a numerical value that is within the general standard error for the measurement of the property that the number A modifies. The number A may, in some instances used in the appended claims, deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel properties of the claimed invention. Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein.

Example 1.
1. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising an aerosol-generating substrate, the aerosol-generating substrate being in the form of a hollow tubular segment defining a substrate cavity extending from an upstream end of the aerosol-generating substrate to a downstream end of the aerosol-generating substrate.
Example 2.
2. The aerosol-generating article of example 1, further comprising an airflow guiding element, the airflow guiding element extending longitudinally into the substrate cavity.
Example 3.
An aerosol-generating article as described in example 2, wherein the airflow channel is defined between an outer surface of the airflow guiding element and an inner surface of the aerosol-generating substrate.
Example 4.
An aerosol-generating article as described in example 2 or 3, wherein the width or diameter of the airflow guiding element is smaller than the diameter of the substrate cavity.
Example 5.
An aerosol-generating article as described in any one of Examples 2 to 4, further comprising an upstream section located upstream of the aerosol-generating substrate, the upstream section including an upstream element adjacent to an upstream end of the aerosol-generating substrate, and the airflow guiding element being coupled to or held by the upstream element.
Example 6.
An aerosol-generating article according to any one of claims 2 to 5, wherein the width or diameter of the airflow guiding element varies along its length.
Example 7.
An aerosol-generating article according to any one of Examples 2 to 6, wherein a portion of the airflow guiding element contacts a portion of the aerosol-generating substrate.
Example 8.
An aerosol-generating article according to any one of Examples 2 to 7, wherein a portion of the airflow guiding element has a width or diameter that substantially corresponds to a diameter of the substrate cavity.
Example 9.
An aerosol-generating article according to any one of Examples 2 to 8, wherein the airflow guiding elements extend along at least 25 percent of the length of the substrate cavity.
Example 10.
An aerosol-generating article according to any one of Examples 2 to 9, wherein the airflow guiding element extends along at least 50 percent of the length of the substrate cavity.
Example 11.
An aerosol-generating article according to any one of Examples 2 to 10, wherein the airflow guiding elements extend along at least 60 percent of the length of the substrate cavity.
Example 12.
An aerosol-generating article according to any one of Examples 2 to 11, wherein the airflow guiding element comprises a central core portion and an extension portion located along the core portion, the extension portion extending outwardly from the core portion.
Example 13.
13. The aerosol-generating article of example 12, wherein the extension portion is shaped substantially in the form of a hemisphere, a sphere, a cylinder, a cone, or a ring.
Example 14.
14. The aerosol-generating article of example 12 or 13, wherein the core portion is shaped substantially in the form of a rod, tube, or cone.
Example 15.
An aerosol-generating article according to any one of Examples 12 to 14, wherein the airflow guiding element comprises at least two extension portions located along the core portion.
Example 16.
An aerosol-generating article according to any one of Examples 12 to 14, wherein the airflow guiding element comprises at least two extension portions, each extension portion being located at a different position along the core portion.
Example 17.
An aerosol-generating article according to any one of Examples 2 to 16, wherein the airflow guiding element comprises a hollow tube.
Example 18.
18. The aerosol-generating article of any one of Examples 2-17, further comprising a base support element, the airflow guiding element extending from the base support element.
Example 19.
An aerosol-generating article as described in Example 18, wherein the base support element is located upstream of the rod of the aerosol-generating substrate.
Example 20.
20. The aerosol-generating article of example 18 or 19, wherein the base support element is located within the upstream section or element of the aerosol-generating article.
Example 21.
20. The aerosol-generating article of example 18 or 19, wherein the base support element is held within the upstream element of the aerosol-generating article.
Example 22.
An aerosol-generating article described in any one of Examples 18 to 21, wherein the base support element is porous or includes at least one opening such that fluid communication is established between the exterior of the aerosol-generating article and the interior of the aerosol-generating substrate.
Example 23.
23. The aerosol-generating article of any one of Examples 2 to 22, wherein the outer longitudinal surface of the airflow guiding element and the inner longitudinal surface of the aerosol-generating substrate define an airflow channel.
Example 24.
The aerosol-generating article of example 5, wherein the upstream element comprises a solid plug segment.
Example 25.
The aerosol-generating article of example 5, wherein the upstream element comprises a hollow tubular segment.
Example 26.
An aerosol-generating article described in any one of Examples 2 to 25, wherein the airflow guiding element includes an airflow inlet at a first location and an airflow outlet at a second location downstream of the first location, such that an airflow path is defined along and within the airflow guiding element.
Example 27.
An aerosol-generating article as described in any one of Examples 2 to 26, further comprising a downstream section located downstream of the aerosol-generating substrate, the downstream section comprising one or more of a mouthpiece element and a hollow tubular element.
Example 28.
28. The aerosol-generating article of example 27, wherein the mouthpiece element comprises at least one mouthpiece filter segment formed from a fibrous filtration material.
Example 29.
An aerosol-generating article according to any one of Examples 1 to 28, wherein the aerosol-generating substrate has a length of from 5 millimeters to 30 millimeters.
Example 30.
An aerosol-generating article according to any one of Examples 1 to 29, wherein the aerosol-generating substrate has a length of from 5 millimeters to 16 millimeters.
Example 31.
An aerosol-generating article according to any one of Examples 1 to 30, wherein the wall thickness of the aerosol-forming substrate is from 5 percent to 40 percent of the outer diameter of the aerosol-generating substrate.
Example 32.
An aerosol-generating article according to any one of Examples 1 to 31, wherein the wall thickness of the aerosol-generating substrate is at least 200 micrometers.
Example 33.
An aerosol-generating article as described in any one of Examples 1 to 32, wherein the aerosol-generating substrate comprises homogenized tobacco material.
Example 34.
An aerosol-generating article according to any one of Examples 1 to 33, wherein the aerosol-generating substrate is formed from a plurality of overlapping sheets of homogenized tobacco material.
Example 35.
An aerosol-generating article according to any one of Examples 1 to 36, wherein the aerosol-generating substrate comprises one or more aerosol formers, and the content of the aerosol formers in the aerosol-generating substrate is from 10 percent by weight to 20 percent by weight on a dry weight basis.
Example 36.
An aerosol-generating article according to any one of Examples 2 to 35, wherein a portion of the airflow guiding element is coated with one or more of a further aerosol-generating substrate, a flavourant, and an aerosol former.
Example 37.
37. The aerosol-generating article of example 35 or 36, wherein the aerosol former comprises one or more of glycerin and propylene glycol.
Example 38.
The aerosol-generating article of any one of Examples 2 to 37, wherein the maximum width or diameter of the portion of the air flow guiding element that extends into the substrate cavity is at least about 25 percent of the diameter of the substrate cavity.
Example 39.
An aerosol-generating article according to any one of Examples 2 to 37, wherein the maximum width or diameter of the portion of the air flow guiding element that extends into the substrate cavity is at least 50 percent of the diameter of the substrate cavity.
Example 40.
The aerosol-generating article of any one of Examples 2 to 37, wherein the maximum width or diameter of the portion of the air flow guiding element that extends into the substrate cavity is at least about 75 percent of the diameter of the substrate cavity.
Example 41.
An aerosol-generating article according to any one of Examples 2 to 40, wherein the outer surface of the airflow guiding element is textured.
Example 42.
An aerosol generating system comprising an aerosol generating article described in any one of Examples 1 to 41, and an aerosol generating device including a heating chamber for receiving the aerosol generating article and a heating element provided at or around the heating chamber.

The specific embodiments and examples described above are illustrative of the present invention, but are not limiting. It is understood that other embodiments of the present invention may be made, and that the specific embodiments and examples described herein are not exhaustive.

Claims (15)

1. An aerosol-generating article for generating an inhalable aerosol upon heating, said aerosol-generating article comprising:
an aerosol-generating substrate, the aerosol-generating substrate being in the form of a hollow tubular segment defining a substrate cavity extending from an upstream end of the aerosol-generating substrate to a downstream end of the aerosol-generating substrate;
an upstream section located upstream of the aerosol-generating substrate, the upstream section comprising an upstream element adjacent the upstream end of the aerosol-generating substrate;
an airflow guiding element coupled to the upstream element and extending longitudinally into the substrate cavity, an airflow channel being defined between an outer surface of the airflow guiding element and an inner surface of the aerosol-generating substrate. The aerosol-generating article of claim 1, wherein the width or diameter of the airflow guiding element is smaller than the diameter of the base cavity. The aerosol-generating article of claim 1 or 2, wherein the width or diameter of the airflow guiding element varies along its length. The aerosol-generating article according to any one of claims 1 to 3, wherein the outer surface of the airflow guiding element is textured or unevenly textured. The aerosol-generating article of any one of claims 1 to 4, wherein the airflow guiding element extends along at least 50 percent of the length of the substrate cavity. The aerosol-generating article according to any one of claims 1 to 5, wherein the airflow guide element comprises a hollow tube. The aerosol-generating article according to any one of claims 1 to 6, wherein the airflow guiding element comprises an elongated body including a central core portion and an extension portion located along the core portion, the extension portion extending outwardly from the core portion. The aerosol-generating article of claim 7, wherein the airflow guiding element includes at least two extension portions located along the core portion. The aerosol-generating article according to any one of claims 1 to 8, further comprising a base support element located upstream of the aerosol-generating substrate, the airflow guiding element extending from the base support element. The aerosol-generating article of claim 9, wherein the base support element is porous or includes at least one opening such that fluid communication is established between the exterior of the aerosol-generating article and the interior of the aerosol-generating substrate through the base support element. The aerosol-generating article of any one of claims 1 to 10, wherein the airflow guiding element includes an airflow inlet at a first location and an airflow outlet at a second location downstream of the first location such that an airflow path is defined within and along the airflow guiding element. An aerosol-generating article according to any one of Examples 1 to 11, in which the wall thickness of the aerosol-forming substrate is 5 percent to 40 percent of the outer diameter of the aerosol-generating substrate. The aerosol-generating article of any one of claims 1 to 12, wherein the maximum width or diameter of the portion of the airflow guiding element that extends into the substrate cavity is at least about 25 percent of the diameter of the substrate cavity. The aerosol-generating article according to any one of claims 1 to 13, wherein the airflow guiding element does not contact the inner surface of the aerosol-generating substrate. An aerosol generating system comprising an aerosol generating article according to any one of claims 1 to 14, and an aerosol generating device including a heating chamber for receiving the aerosol generating article and a heating element provided around or around the heating chamber.

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