WO2025114395A1

WO2025114395A1 - Aerosol-generating article comprising tubular element having integral first and second tubular portions

Info

Publication number: WO2025114395A1
Application number: PCT/EP2024/083827
Authority: WO
Inventors: Antonio CONSOLANTE; Pedro Santos EFFERTZ; Marc Antonius Friedrich VAN DEN BOOGAART
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2023-11-27
Filing date: 2024-11-27
Publication date: 2025-06-05
Anticipated expiration: 2026-05-27

Abstract

An aerosol-generating article (1) comprising: a substrate element (2) comprising an aerosol-generating substrate; and a tubular element (12) comprising integral first (14) and second (16) tubular portions, wherein the first tubular portion and second tubular portion each constitute at least 10 percent of the length of the tubular element; wherein the first tubular portion has a first internal diameter (D1_int) and the second tubular portion has a second internal diameter (D2_int); wherein the first internal diameter is different to the second internal diameter; the second internal diameter being greater than the first internal diameter; wherein the first tubular portion comprises an inner tube segment (15) and a first part of an outer tube segment (17) arranged around the inner tube segment, wherein the second tubular portion comprises a second part of the outer tube segment that extends beyond an end of the inner tube segment in a longitudinal direction of the tubular element, the first internal diameter being the internal diameter of the inner tube segment and the second internal diameter being the internal diameter of the second part of the outer tube segment; and wherein the outer tube segment comprises one or more layers of a web material, the web material being parallel wrapped around the inner tube segment.

Description

AEROSOL-GENERATING ARTICLE COMPRISING TUBULAR ELEMENT HAVING INTEGRAL FIRST AND SECOND TUBULAR PORTIONS

The present disclosure relates to an aerosol-generating article comprising an aerosolgenerating substrate for generating an inhalable aerosol, for example, upon heating. The present disclosure also relates to a method of manufacturing a tubular element for the aerosolgenerating article.

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 aerosol-generating articles an aerosol is generated by the transfer of 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.

A number of aerosol-generating devices for consuming heated aerosol-generating articles are known in the art. Such devices include, for example, electrically heated aerosolgenerating devices in which an aerosol is generated by the transfer of heat from one or more electrical heater elements of the aerosol-generating device to the aerosol-generating substrate of a heated aerosol-generating article. For example, electrically heated aerosolgenerating devices have been proposed that comprise an internal resistive heater blade which is adapted to be inserted into the aerosol-generating substrate. As an alternative, inductively heatable aerosol-generating articles comprise a susceptor element arranged within the aerosol-generating substrate that can be heated by an alternating magnetic field provided by the aerosol-generating device.

Heated aerosol-generating articles are typically cigarette-shaped and comprise a plurality of elements or plugs. For example, such articles typically comprise a substrate plug including an aerosol-generating substrate, a tubular plug downstream of the substrate plug and a mouthpiece filter plug at a mouth end of the article. The tubular plug has an internal cavity or empty core that defines an airflow pathway. It is known to have two tubular plugs: a first tubular plug that functions as a spacer between the substrate plug and other components of the aerosol-generating article; and a separate second tubular plug that functions as an air cooler for cooling air as it passes through the aerosol-generating article to help form an aerosol. The second tubular plug generally abuts the first tubular plug.

Aerosol-generating articles in the form of inhaler articles, such as dry powder inhalers, are known in the art. Some dry powder inhalers have a component for storing the dry powder, such as a capsule. The capsule may be activated by being pierced by a separate piercing element, such as a piercing element of a holder. Once the capsule has been activated, a consumer may draw on a mouth end of the inhaler to generate an air flow through the inhaler. Each air flow from each inhalation may carry a portion of the dry powder from the capsule to the lungs of the user. Such aerosol-generating articles may generate an aerosol without heating.

Aerosol-generating articles such as dry powder inhalers generally comprise a retention plug or element having a cavity or empty core that defines an airflow pathway and which helps to hold, or otherwise resist movement of, the capsule so that the capsule can be easily pierced. Such retention plugs are typically formed of two tubular plugs: a first tubular plug that extends across and is fixed to an interior of the aerosol-generating article; and a second separate smaller tubular plug fixed to the first tubular plug on a side of the first tubular plug facing the capsule. The smaller diameter of the second tubular plug provides a well or gutter between its external tubular surface and an internal surface of the aerosol-generating article that collects dry powder and reduces the likelihood of the dry powder leaking out of the article once the capsule has been pierced, for example, if the article is inclined.

Manufacturing and assembling the first and second tubular plugs of both heated aerosol-generating articles and non-heated aerosol-generating articles such as dry powder inhalers can be difficult because the airflow is restricted to their internal cavities. The ability of the first and second tubular plugs to perform their respective functions depends on how accurately they are positioned and aligned. The quality and consistency of a consumer experience may depend on the internal air path through the aerosol-generating article and therefore it is important that the first and second tubular plugs are abutted and concentric. Furthermore, aerosol-generating article can be susceptible to breakage at the interface between the first and second tubular plugs when a force is applied to the aerosol-generating article, for example, during insertion of the aerosol-generating article into an aerosolgenerating device.

It would be desirable to provide an aerosol-generating article that is easier to manufacture and reduces the need for accurate positioning and alignment of tubular plugs or elements. It would be desirable to provide an aerosol-generating article that is less susceptible to breakage at the interface between the first and second tubular plugs.

According to an example of the present disclosure, there is provided an aerosolgenerating article. The aerosol-generating article may comprise a substrate element comprising an aerosol-generating substrate. The aerosol-generating article may comprise a tubular element. The tubular element may comprise a first tubular portion. The tubular element may comprise a second tubular portion. The first and second tubular portions may be integral. The first tubular portion may constitute at least 10 percent of the length of the tubular element. The second tubular portion may constitute at least 10 percent of the length of the tubular element.

In one example, the first tubular portion may have a first internal diameter. The second tubular portion may have a second internal diameter. The first internal diameter may be different to the second internal diameter.

In another example, the first tubular portion may have a first external diameter. The second tubular portion may have a second external diameter. The first external diameter may be different to the second external diameter.

According to an example of the present disclosure, there is provided an aerosolgenerating article comprising: a substrate element comprising an aerosol-generating substrate; and a tubular element comprising integral first and second tubular portions. The first tubular portion and second tubular portion each constitute at least 10 percent of the length of the tubular element. The first tubular portion has a first internal diameter and the second tubular portion has a second internal diameter and the first internal diameter is different to the second internal diameter. Alternatively or in addition, the first tubular portion has a first external diameter and the second tubular portion has a second external diameter and the first external diameter is different to the second external diameter.

The term “aerosol-generating article” is used herein to denote an article in which an inhalable aerosol is generated from an aerosol-generating substrate and delivered to a consumer. As used herein, the term “aerosol-generating substrate” denotes a substrate from which an aerosol can be formed or generated. For example, the aerosol-generating substrate may be capable of releasing volatile compounds upon heating to generate an aerosol. Alternatively, the aerosol-generating substrate may comprise particles that can be entrained in an airflow to generate an aerosol.

As used herein, the term "tubular element" denotes a generally hollow elongate element defining a lumen or airflow passage along a longitudinal axis thereof. In particular, the term "tubular" will be used with reference to a tubular element having a substantially cylindrical cross-section and defining at least one airflow conduit establishing an uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it will be understood that alternative geometries (for example, alternative cross-sectional shapes) of the tubular element may be possible. The tubular element is an individual, discrete component of the aerosol-generating article.

As used herein with respect to the first and second tubular portions of the tubular element, the term “integral” is intended to mean that the first and second tubular portions each form part of the tubular element rather than being separate components. Therefore, the tubular element comprising the first and second tubular portions is a single component of the aerosol-generating article. The first and second tubular portions cannot be separated without applying a force that would damage or destroy the tubular element.

With respect to the aerosol-generating article, the term “length” denotes the dimension of a component of the aerosol-generating article in the longitudinal direction of the aerosolgenerating article. The longitudinal direction of the aerosol-generating article refers to the direction corresponding to the main longitudinal axis of the aerosol-generating article, which extends between the upstream and downstream ends of the aerosol-generating article. As used herein, the terms “upstream” and “downstream” describe the relative positions of elements, or portions of elements, of the aerosol-generating article in relation to the direction in which the aerosol is transported through the aerosol-generating article during use.

By providing a tubular element having integral first and second tubular portions, the first and second tubular portions advantageously each form part of the tubular element rather than being separate components. This helps to alleviate any difficulties in positioning the first and second tubular portions relative to each other during assembly of the aerosol-generating article compared to forming the first and second tubular portions as separate elements. There is no need to accurately bring the first and second tubular portions into abutting engagement during assembly of the aerosol-generating article because the tubular element with integral first and second tubular portions is already assembled and automatically achieves the advantages of this configuration. The integral nature of the tubular element also helps to ensure that the first and second tubular portions are axially aligned. This ensures a smooth airflow through the tubular element and helps to provide a consistent consumer experience.

In addition, providing a tubular element having integral first and second tubular portions advantageously helps to strengthen the tubular element and reduce the risk of damage or breakage of the tubular element at the interface between the first and second tubular when a force is applied to the aerosol-generating article, for example, during insertion of the aerosolgenerating article into an aerosol-generating device.

The first tubular portion and second tubular portion may each constitute at least 20 percent of the length of the tubular element, preferably at least 30 percent of the length of the tubular element, and more preferably at least 40 percent of the length of the tubular element. In a preferred example, the first tubular portion and second tubular portion may each constitute about 50 percent of the length of the tubular element.

The first tubular portion may have a uniform or constant first internal diameter over the length of the first tubular portion. The second tubular portion may have a uniform or constant second internal diameter over the length of the second tubular portion. The first tubular portion may have a uniform or constant first external diameter over the length of the first tubular portion. The second tubular portion may have a uniform/ or constant second external diameter over the length of the second tubular portion.

The differences in internal or external diameters may be formed by a step in the internal or external surface of the tubular element. The difference between the first internal diameter and the second internal diameter may be formed by a step in the internal surface of the tubular element. The difference between the first external diameter and the second external diameter may be formed by a step in the external surface of the tubular element.

The differences in internal or external diameters are at least 0.2 millimetres, optionally at least 0.5 millimetres, optionally at least 0.7 millimetres, optionally at least 1 millimetre, optionally at least 1.5 millimetres, optionally at least 2 millimetres and further optionally at least 2.5 millimetres. The differences in internal or external diameters may be between about 0.2 millimetres and 2.5 millimetres, optionally between 0.5 millimetres and 2.0 millimetres, optionally between 0.7 millimetres and 2.0 millimetres, and optionally between 1 millimetre and 2 millimetres.

In one example aerosol-generating article, the first and second tubular portions may have different first and second internal diameters respectively. The second tubular portion may be arranged downstream of the first tubular portion.

The second internal diameter may be greater than the first internal diameter. The second internal diameter may be at least 1 millimetre greater than the first internal diameter. Optionally, the second internal diameter may be at least 1.2 millimetres greater than the first internal diameter. Optionally, the second internal diameter may be at least 1.4 millimetres greater than the first internal diameter. Optionally, the second internal diameter may be at least 1.6 millimetres greater than the first internal diameter. Optionally, the second internal diameter may be at least 1.8 millimetres greater than the first internal diameter. Optionally, the second internal diameter may be at least 2.0 millimetres greater than the first internal diameter.

The difference between the first and second internal diameters may be between about 0.5 and about 3.0 millimetres, optionally between about 1 millimetre and about 2.5 millimetres and further optionally between about 1 .5 millimetres and about 2.0 millimetres. In a preferred example, the difference between the first and second internal diameters may be about 1.7 millimetres.

A ratio of the second internal diameter to the first internal diameter may be between 1.2 and 2.5, optionally between 1.2 and 2.0, further optionally between 1.3 and 1.7 and yet further optionally between 1.4 and 1.6. In one example, a ratio of the second internal diameter to the first internal diameter may be about 1.4. In another example, a ratio of the second internal diameter to the first internal diameter may be between about 2.0 and about 2.5.

The first tubular portion may comprise an inner tube segment. The first tubular portion may comprise a first part of an outer tube segment. The first part of the outer tube segment may be arranged around the inner tube segment. The second tubular portion may comprise a second part of the outer tube segment. The second part of the outer tube segment may extend beyond an end of the inner tube segment in a longitudinal direction of the tubular element. The first internal diameter may be the internal diameter of the inner tube segment. The second internal diameter may be the internal diameter of the second part of the outer tube segment.

Advantageously, by forming the tubular element from inner and outer tube segments, it is possible to use different materials for forming each of the inner and outer tube segments. In particular, different materials can be selected for forming the inner and outer tube segments depending on the particular physical requirements of each of the inner and outer tube segments.

The outer tube segment may overlap the inner tube segment. The outer tube segment may overlap at least 50 percent of the length of the inner tube segment, preferably at least 60 percent of the length of the inner tube segment, more preferably at least 70 percent of the length of the inner tube segment, yet more preferably at least 80 percent of the length of the inner tube segment, and yet more preferably at least 90 percent of the length of the inner tube segment. The outer tube segment may overlap the entire length of the inner tube segment.

The inner tube segment may comprise a plurality of layers of a first web material. The inner tube segment may comprise between 1 and 20 layers of the first web material. The inner tube segment may comprise a plurality of substantially continuous strips of the first web material.

The outer tube segment may comprise a plurality of layers of the first web material. The outer tube segment may comprise between 1 and 20 layers of the first web material. The outer tube segment may comprise a plurality of substantially continuous strips of the first web material.

The substantially continuous strips may be spirally wound. As used herein, the term “spirally wound” or “spiral winding” refers to a process of forming a tube by winding at least one substantially continuous strip of web material in a spiral or helical manner around a forming means, such as an elongate cylindrical mandrel. The at least one strip of web material is fed to the mandrel such that an incoming direction of the at least one strip of web material forms an acute angle with the longitudinal axis of the mandrel.

The inner tube segment and the outer tube segment may comprise a plurality of spirally wound substantially continuous strips of the first web material. The first web material may comprise any suitable web material. For example, the first web material may comprise one or more of paper, cardboard, acetate tow or polylactic acid (PLA). In one example, the first web material may comprise a cellulosic material such as paper or cardboard.

The width of the substantially continuous strips may be between 10 millimetres and 50 millimetres. The thickness of the first web material may be between 0.05 millimetres and 0.1 millimetres.

The outer tube segment may comprise one or more layers of a second web material. The second web material may be parallel wrapped around the inner tube segment. As used herein, the term “parallel wrapped” refers to a process of forming a tube by wrapping another element, for example, the inner tube segment, in a web material such that the opposing side edges of the web material are brought together in a parallel manner.

The outer tube segment may comprise a plurality of layers of the second web material parallel wrapped around the inner tube segment. The outer tube segment may comprise between 1 and 20 layers of the second web material.

The second web material may comprise any suitable web material. For example, the second web material may comprise one or more of paper, cardboard, acetate tow or polylactic acid (PLA). In one example, the second web material may comprise a cellulosic material such as paper or cardboard.

The thickness of the second web material may be between 0.05 millimetres and 1.1 millimetres.

The tubular element may be hollow. The tubular element may be hollow over its entire length.

The first tubular portion of the tubular element may define a first internal cavity of the tubular element that extends from an upstream end of the first tubular portion to a downstream end of the first tubular portion. The first internal diameter being an internal diameter of the first internal cavity. The first internal cavity may define at least part of an airflow pathway through the tubular element. The first internal cavity may be substantially empty to allow substantially unrestricted airflow along the first internal cavity. The resistance to draw (RTD) of the first tubular portion may be substantially 0 millimetres H2O. Therefore, the first tubular portion does not substantially contribute to the overall RTD of the aerosol-generating article. The first tubular portion of the tubular element may be configured to act as a spacer or support element for the aerosol-generating article.

The second tubular portion of the tubular element may define a second internal cavity of the tubular element that extends from an upstream end of the second tubular portion to a downstream end of the second tubular portion. The second internal cavity may define at least part of an airflow pathway through the tubular element. The second internal cavity may be substantially empty to allow substantially unrestricted airflow along the second internal cavity. The RTD of the second tubular portion may be substantially 0 millimetres H2O. Therefore, the second tubular portion does not substantially contribute to the overall RTD of the aerosolgenerating article. The second tubular portion of the tubular element may be configured to act as an aerosol-cooling element for the aerosol-generating article.

The tubular element may be arranged in alignment with, and downstream of, the substrate element. In a preferred example, the tubular element is located immediately downstream of the substrate element. An upstream end of the tubular element may abut a downstream end of the substrate element.

The tubular element preferably has an external diameter that is approximately equal to the external diameter of the substrate element and to the external diameter of the aerosolgenerating article.

The tubular element may have an external diameter of between 5 millimetres and 12 millimetres, for example of between 5 millimetres and 10 millimetres or of between 6 millimetres and 8 millimetres. In a preferred example, the tubular element has an external diameter of 7.1 millimetres plus or minus 10 percent.

The first tubular portion of the tubular element may have an internal diameter of at least about 2.5 millimetres, preferably at least about 3.0 millimetres, and more preferably at least about 3.5 millimetres. Alternatively or in addition, the first tubular portion of the tubular element may have an internal diameter of less than about 4.0 millimetres, preferably less than about 3.5 millimetres or less than about 3.0 millimetres.

The first tubular portion of the tubular element may have an internal diameter between about 2.0 millimetres and about 4.0 millimetres, preferably between about 2.5 millimetres and about 3.5 millimetres, and more preferably between about 3.0 millimetres and 3.5 millimetres. In a preferred example, the first tubular portion of the tubular element may have an internal diameter of about 3.3 millimetres.

A peripheral wall of the first tubular portion may have a thickness of at least about 1 millimetre, preferably at least about 1 .5 millimetres or at least about 2 millimetres. Alternatively or in addition, a peripheral wall of the first tubular portion may have a thickness of less than about 3 millimetres, preferably less than about 2.5 millimetres or less than about 2 millimetres.

A peripheral wall of the first tubular portion may have a thickness between about 1 millimetre and about 3 millimetres, preferably between about 1.5 millimetres and about 2.5 millimetres and more preferably between about 1.5 millimetres and 2.0 millimetres. In a preferred example, a peripheral wall of the first tubular portion may have a thickness of about 1.9 millimetres. The first tubular portion of the tubular element may have a length of at least about 5 millimetres, preferably at least about 6 millimetres and more preferably at least about 7 millimetres. The first tubular portion of the tubular element may have a length of less than about 15 millimetres, preferably less than about 12 millimetres and more preferably less than about 10 millimetres.

The first tubular portion of the tubular element may have a length between about 5 millimetres and about 15 millimetres, preferably between about 6 millimetres and 12 millimetres, and more preferably between about 7 millimetres and 10 millimetres. In a preferred example, the first tubular portion of the tubular element may have a length of about 8 millimetres or about 9 millimetres.

The second tubular portion of the tubular element may have an internal diameter of at least about 4.0 millimetres, preferably at least about 4.5 millimetres, and more preferably at least about 5.0 millimetres. Alternatively or in addition, the second tubular portion of the tubular element may have an internal diameter of less than about 6.0 millimetres, preferably less than about 5.5 millimetres or less than about 5.0 millimetres.

The second tubular portion of the tubular element may have an internal diameter between about 4.0 millimetres and about 6.0 millimetres, preferably between about 4.5 millimetres and about 6.0 millimetres, and more preferably between about 4.5 millimetres and 5.5 millimetres. In a preferred example, the second tubular portion of the tubular element may have an internal diameter of about 5.0 millimetres.

A peripheral wall of the second tubular portion may have a thickness of at least about 0.3 millimetres, preferably at least about 0.6 millimetres, and more preferably at least about 0.9 millimetres. Alternatively or in addition, a peripheral wall of the second tubular portion may have a thickness of less than about 2.5 millimetres, preferably less than about 2.0 millimetres, and more preferably less than about 1.5 millimetres.

A peripheral wall of the second tubular portion may have a thickness between about 0.3 millimetres and 2.5 millimetres, preferably between about 0.6 millimetres and 2.0 millimetres, and more preferably between about 0.9 millimetres and 1.5 millimetres. In a preferred example, a peripheral wall of the second tubular portion may have a thickness of about 1.05 millimetres.

The second tubular portion of the tubular element may have a length of at least about 5 millimetres, preferably at least about 6 millimetres and more preferably at least about 7 millimetres. The second tubular portion of the tubular element may have a length of less than about 15 millimetres, preferably less than about 12 millimetres and more preferably less than about 10 millimetres.

The second tubular portion of the tubular element may have a length between about 5 millimetres and about 15 millimetres, preferably between about 6 millimetres and 12 millimetres, and more preferably between about 7 millimetres and 10 millimetres. In a preferred example, the second tubular portion of the tubular element may have a length of about 8 millimetres.

The aerosol-generating article may further comprise a ventilation zone provided at a position along the second tubular portion. The inventors have found that a satisfactory cooling of the stream of aerosol generated upon heating the aerosol-generating substrate and drawing the aerosol through the tubular element may be achieved by providing a ventilation zone at a location along the second tubular portion.

The ventilation zone may comprise a plurality of ventilation holes or perforations through the peripheral wall of the second tubular portion. Preferably, the ventilation zone comprises at least one circumferential row of perforations. In some examples, the ventilation zone may comprise two circumferential rows of perforations. Preferably, each circumferential row of perforations comprises from 8 to 30 perforations.

The aerosol-generating article may have a ventilation level of at least about 5 percent.

The term “ventilation level” is used herein to denote a volume ratio between of the airflow admitted into the aerosol-generating article via the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the higher the dilution of the aerosol flow delivered to the consumer.

The aerosol-generating article may have a ventilation level of at least about 10 percent, preferably at least about 15 percent, more preferably at least about 20 percent. The aerosolgenerating article may have a ventilation level of less than about 60 percent, preferably less than about 45 percent, more preferably less than about 40 percent. In a preferred example, the aerosol-generating article has a ventilation level of about 25 percent or 30 percent.

The aerosol-generating article may comprise a plurality of elements assembled in the form of a rod.

The aerosol-generating article may comprise a downstream section at a location downstream of the substrate element. The downstream section may comprise one or more downstream elements. The downstream section may comprise the tubular element. The downstream section may comprises a mouthpiece element.

The mouthpiece element may be arranged in alignment with, and downstream of, the tubular element. In a preferred example, the mouthpiece element is located immediately downstream of the tubular element. An upstream end of the mouthpiece element may abut a downstream end of the tubular element.

The mouthpiece element is preferably located at the downstream end or mouth end of the aerosol-generating article. The mouthpiece element comprises at least one mouthpiece filter segment of a fibrous filtration material for filtering the aerosol that is generated from the aerosol-generating substrate. Suitable fibrous filtration materials would be known to the skilled person. Particularly preferably, the at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed of cellulose acetate tow.

Preferably, the mouthpiece element has a low particulate filtration efficiency.

Preferably, the mouthpiece element is circumscribed by a plug wrap. Preferably, the mouthpiece element is unventilated such that air does not enter the aerosol-generating article along the mouthpiece element.

The mouthpiece element is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article by means of a tipping wrapper.

The mouthpiece element preferably has an external diameter that is approximately equal to the external diameter of the aerosol-generating article. The mouthpiece element may have an external diameter of between about 5 millimetres and about 10 millimetres, or between about 6 millimetres and about 8 millimetres. In a preferred example, the mouthpiece element has an external diameter of approximately 7.1 millimetres.

The mouthpiece element preferably has a length of at least about 5 millimetres, preferably at least about 8 millimetres, more preferably at least about 10 millimetres. Alternatively or in addition, the mouthpiece element preferably has a length of less than about 25 millimetres, preferably less than about 20 millimetres, more preferably less than about 15 millimetres.

The mouthpiece element may have a length of between about 5 millimetres and about 25 millimetres, or between about 8 millimetres and about 20 millimetres, or between about 10 millimetres and about 15 millimetres. In a preferred example, the mouthpiece element has a length of approximately 12 millimetres.

The substrate element may be arranged in alignment with, and upstream of, the tubular element. The substrate element may abut the tubular element. In a preferred example, the substrate element is located immediately upstream of the tubular element. A downstream end of the substrate element may abut an upstream end of the tubular element.

Preferably, the substrate element is circumscribed by a plug wrap.

The substrate element preferably has an external diameter that is approximately equal to the external diameter of the aerosol-generating article. The substrate element may have an external diameter of between about 5 millimetres and about 10 millimetres, or between about 6 millimetres and about 8 millimetres. In a preferred example, the substrate element has an external diameter of approximately 7.1 millimetres.

The substrate element preferably has a length of at least about 5 millimetres, preferably at least about 8 millimetres, more preferably at least about 10 millimetres. Alternatively or in addition, the substrate element preferably has a length of less than about 25 millimetres, preferably less than about 20 millimetres, more preferably less than about 15 millimetres.

The substrate element may have a length of between about 5 millimetres and about 25 millimetres, or between about 8 millimetres and about 20 millimetres, or between about 10 millimetres and about 15 millimetres. In a preferred example, the substrate element has a length of approximately 11 millimetres or approximately 12 millimetres.

As described above, the substrate element comprises an aerosol-generating substrate. The aerosol-generating substrate may be a solid aerosol-generating substrate.

The aerosol-generating substrate preferably comprises an aerosol former.

The aerosol former may be any suitable known compound or mixture of compounds that, in use, facilitates formation of a dense and stable aerosol. The aerosol former may be facilitating that the aerosol is substantially resistant to thermal degradation at temperatures typically applied during use of the aerosol-generating article. Suitable aerosol formers are for example: polyhydric alcohols such as, for example, triethylene glycol, 1 ,3-butanediol, propylene glycol and glycerine; esters of polyhydric alcohols such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol former comprises one or more of glycerine and propylene glycol. The aerosol former may consist of glycerine or propylene glycol or of a combination of glycerine and propylene glycol.

The aerosol-generating substrate may comprise at least about 5 percent, at least about 10 percent, or at least about 12 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

The aerosol-generating substrate may comprise less than or equal to about 30 percent, less than or equal to about 25 percent, or less than or equal to about 20 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

The aerosol-generating substrate may comprise between about 5 percent and about 30 percent, between about 5 percent and about 25 percent, or between about 5 percent and about 20 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

The aerosol-generating substrate may comprise between about 10 percent and about 30 percent, between about 10 percent and about 25 percent, or between about 10 percent and about 20 percent by weight of aerosol former on a dry weight basis of the aerosolgenerating substrate. The aerosol-generating substrate may comprise between about 12 percent and about 30 percent, between about 12 percent and about 25 percent, or between about 12 percent and about 20 percent by weight of aerosol former on a dry weight basis of the aerosolgenerating substrate.

The aerosol-generating substrate may comprise a plurality of shreds of tobacco material. The aerosol-generating substrate may comprise a plurality of shreds of homogenised tobacco material.

As used herein, the term “shred” denotes an element having a length substantially greater than a width and a thickness thereof.

As used herein, the term “homogenised tobacco material” is used to describe material formed by agglomerating particulate tobacco material.

Shreds of homogenised tobacco material may be formed from a sheet of homogenised tobacco material, for example, by cutting or shredding. Shreds of homogenised tobacco material may be formed by other methods, for example, by extrusion.

The shreds of tobacco material may have a width of at least about 0.3 millimetres, at least about 0.5 millimetres, or at least about 0.6 millimetres.

The shreds of tobacco material may have a width of less than or equal to about 2 millimetres, less than or equal to about 1.2 millimetres, or less than about 0.9 millimetres.

The shreds of tobacco material may have a width of between about 0.3 millimetres and about 2 millimetres, between about 0.3 millimetres and about 1.2 millimetres, or between about 0.3 millimetres and about 0.9 millimetres.

The shreds of tobacco material may have a width of between about 0.5 millimetres and about 2 millimetres, between about 0.5 millimetres and about 1.2 millimetres, or between about 0.5 millimetres and about 0.9 millimetres.

The shreds of tobacco material may have a width of between about 0.6 millimetres and about 2 millimetres, between about 0.6 millimetres and about 1.2 millimetres, or between about 0.6 millimetres and about 0.9 millimetres.

The shreds of tobacco material may have a length of at least about 10 millimetres.

The shreds of tobacco material may have a length of less than or equal to about 40 millimetres.

The shreds of tobacco material may have a length of between about 10 millimetres and about 40 millimetres.

At least about 20 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may extend along the entire length of the aerosol-generating substrate. At least about 20 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may have a length substantially the same as the length of the aerosol-generating substrate.

Less than or equal to about 60 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may extend along the entire length of the aerosol-generating substrate. Less than or equal to about 60 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may have a length substantially the same as the length of the aerosol-generating substrate.

Between about 20 percent and 60 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may extend along the entire length of the aerosolgenerating substrate. Between about 20 percent and 60 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may have a length substantially the same as the length of the aerosol-generating substrate.

The size of the components of the aerosol-generating substrate, such as a plurality of shreds of tobacco material, may play a role in the distribution of heat inside the aerosolgenerating substrate. Also, the size of the components of the aerosol-generating substrate may play a role in the RTD of the article.

The aerosol-generating substrate may comprise a plurality of pellets or granules of tobacco material. The aerosol-generating substrate may comprise a plurality of pellets or granules of homogenised tobacco material.

The aerosol-generating substrate may comprise one or more sheets of tobacco material.

The aerosol-generating substrate may comprise one or more sheets of homogenised tobacco material.

The one or sheets of tobacco material may each individually have a thickness of at least about 100 micrometres, at least about 150 micrometres, or at least about 300 micrometres.

As used herein, individual thickness refers to the thickness of the individual sheet of tobacco material, whereas combined thickness refers to the total thickness of all sheets of tobacco material that make up the aerosol-generating substrate. For example, if the aerosolgenerating substrate is formed from two individual sheets of tobacco material, then the combined thickness is the sum of the thickness of the two individual sheets of tobacco material or the measured thickness of the two sheets of tobacco material where the two sheets of tobacco material are stacked in the aerosol-generating substrate.

The one or more sheets of tobacco material may each individually have a thickness of less than or equal to about 600 micrometres, less than or equal to about 300 micrometres, or less than or equal to about 250 micrometres.

The one or more sheets of tobacco material may each individually have a thickness of between about 100 micrometres and about 600 micrometres, between about 100 micrometres and about 300 micrometres, or between about 100 micrometres and about 250 micrometres.

The one or more sheets of tobacco material may each individually have a thickness of between about 150 micrometres and about 600 micrometres, between about 150 micrometres and about 300 micrometres, or between about 150 micrometres and about 250 micrometres.

The one or more sheets of tobacco material may each individually have a thickness of between about 250 micrometres and about 600 micrometres, between about 250 micrometres and about 300 micrometres, or between about 250 micrometres and about 250 micrometres.

The one or more sheets of tobacco material may each individually have a length substantially the same as the length of the aerosol-generating substrate.

The one or more sheets of tobacco material may have been one or more of crimped, folded, gathered, and pleated.

Crimping, folding, gathering, or pleating of the one or more sheets of tobacco material may cause splitting of the one or more sheets of tobacco material to form shreds of tobacco material. For example, the one or more sheets of tobacco material may be crimped to such an extent that the integrity of the one or more sheets of tobacco material becomes disrupted at the plurality of parallel ridges or corrugations causing separation of the material, and results in the formation of shreds of tobacco material.

The aerosol-generating article may comprise a susceptor arranged within the aerosolgenerating substrate. The first element may comprise a susceptor arranged within the aerosol-generating substrate.

As used herein, the term “susceptor” refers to a material that can convert electromagnetic energy into heat. When located within a fluctuating electromagnetic field, eddy currents induced in the susceptor cause heating of the susceptor.

The susceptor is arranged in thermal contact with the aerosol-generating substrate. Thus, when the susceptor heats up, the aerosol-generating substrate is heated by the susceptor to generate an aerosol. The susceptor may be arranged in direct physical contact with the aerosol-generating substrate.

The susceptor may be an elongate susceptor.

As used herein, the term “elongate” is used to describe a component of the aerosolgenerating article having a length greater than the width and thickness thereof.

The elongate susceptor may be arranged substantially longitudinally within the aerosol-generating substrate. That is, the longitudinal axis of the elongate susceptor may be approximately parallel to the longitudinal axis of the aerosol-generating substrate. For example, the longitudinal axis of the elongate susceptor may be within plus or minus 10 degrees of parallel to the longitudinal axis of the aerosol-generating substrate. The elongate susceptor may be located in a radially central position within the aerosol-generating substrate, and extend along the longitudinal axis of the aerosol-generating substrate.

The susceptor may extend from the downstream end of the aerosol-generating substrate towards the upstream end of the aerosol-generating substrate.

The susceptor may extend from the upstream end of the aerosol-generating substrate towards the downstream end of the aerosol-generating substrate.

The susceptor may extends from the upstream end of the aerosol-generating substrate to the downstream end of the aerosol-generating substrate. That is, the susceptor may extend along the entire length of the aerosol-generating substrate.

The length of the susceptor may be substantially the same as the length of the aerosolgenerating substrate.

The susceptor may extend part way along the length of the aerosol-generating substrate.

The susceptor may be spaced apart from the downstream end of the aerosolgenerating substrate.

The susceptor may be spaced apart from the upstream end of the aerosol-generating substrate.

The susceptor may be spaced apart from both a downstream end and an upstream end of the aerosol-generating substrate.

The length of the susceptor may be less than the length of the aerosol-generating substrate.

The susceptor may be entirely enclosed within the aerosol-generating substrate. That is, the aerosol-generating substrate may completely surround the susceptor.

The susceptor may be in the form of a pin, rod, strip or blade.

The susceptor may have a length of at least about 5 millimetres, at least about 6 millimetres, or at least about 8 millimetres. The susceptor may have a length of less than or equal to about 15 millimetres, less than or equal to about 12 millimetres, or less than or equal to about 10 millimetres.

The susceptor may have a length of between about 5 millimetres and about 15 millimetres, between about 5 millimetres and about 12 millimetres, or between about 5 millimetres and about 10 millimetres.

The susceptor may have a length of between about 6 millimetres and about 15 millimetres, between about 6 millimetres and about 12 millimetres, or between about 6 millimetres and about 10 millimetres.

The susceptor may have a length of between about 8 millimetres and about 15 millimetres, between about 8 millimetres and about 12 millimetres, or between about 8 millimetres and about 10 millimetres.

The susceptor may have a width of at least about 1 millimetre.

The susceptor may have width of less than or equal to about 5 millimetres.

The susceptor may have a width of between about 1 millimetre and about 5 millimetres.

The susceptor may have a thickness of at least about 0.01 millimetres, or at least about 0.5 millimetres.

The susceptor may have a thickness of less than or equal to about 2 millimetres, less than or equal to about 500 micrometres, or less than or equal to about 100 micrometres.

The susceptor may have a thickness of between about 10 micrometres and about 2 millimetres, between about 10 micrometres and about 500 micrometres, or between about 10 micrometres and about 100 micrometres.

The susceptor may have a thickness of between about 0.5 millimetres and about 2 millimetres.

The susceptor may have a substantially circular cross-section.

The susceptor may have a substantially constant cross-section along the length of the susceptor.

If the susceptor has the form of a strip or blade, the strip or blade may have a rectangular shape having a width of between about 2 millimetres to about 8 millimetres, or between about 3 millimetres to about 5 millimetres. By way of example, a susceptor in the form of a strip of blade may have a width of about 4 millimetres.

If the susceptor has the form of a strip or blade, the strip or blade may have a rectangular shape and a thickness of between about 0.03 millimetres to about 0.15 millimetres, or between about 0.05 millimetres to about 0.09 millimetres. By way of example, a susceptor in the form of a strip of blade may have a thickness of about 0.07 millimetres, or about 0.06 millimetres.

The susceptor may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. For example, the susceptor may comprise a metal or carbon.

The susceptor may comprise or consist of a ferromagnetic material, for example a ferromagnetic alloy, ferritic iron, or a ferromagnetic steel or stainless steel. A suitable susceptor may be, or comprise, aluminium. The susceptor may be formed from 400 series stainless steels, for example grade 410, or grade 420, or grade 430 stainless steel. Different materials will dissipate different amounts of energy when positioned within electromagnetic fields having similar values of frequency and field strength.

Thus, parameters of the susceptor such as material type, length, width, and thickness may all be altered to provide a desired power dissipation within a known electromagnetic field. The susceptor may be heated to a temperature in excess of 250 degrees Celsius.

Suitable susceptors may comprise a non-metallic core with a metal layer disposed on the non-metallic core, for example metallic tracks formed on a surface of a ceramic core. A susceptor may have a protective external layer, for example a protective ceramic layer or protective glass layer encapsulating the susceptor. The susceptor may comprise a protective coating formed by a glass, a ceramic, or an inert metal, formed over a core of susceptor material.

The susceptor may be a multi-material susceptor and may comprise a first susceptor material and a second susceptor material.

The aerosol-generating article may further comprise an upstream section at a location upstream of the substrate element. The upstream section may comprise one or more upstream elements. In some examples, the upstream section may comprise an upstream element arranged immediately upstream of the substrate element. The upstream element may be arranged in alignment with the substrate element. An downstream end of the upstream element may abut an upstream end of the substrate element. The upstream element may help to reduce the risk of damage to the substrate element or a consumer contacting a hot susceptor.

The upstream element preferably has an external diameter that is approximately equal to the external diameter of the substrate element and to the external diameter of the aerosolgenerating article. The upstream element may have an external diameter of between about 5 millimetres and about 10 millimetres, or between about 6 millimetres and about 8 millimetres. In a preferred example, the upstream element has an external diameter of approximately 7.1 millimetres.

The upstream element preferably has a length of at least about 2 millimetres, preferably at least about 3 millimetres, more preferably at least about 4 millimetres. Alternatively or in addition, the upstream element preferably has a length of less than about 10 millimetres, preferably less than about 8 millimetres, more preferably less than about 6 millimetres.

The upstream element may have a length of between about 2 millimetres and about 10 millimetres, or between about 3 millimetres and about 8 millimetres, or between about 4 millimetres and about 6 millimetres. In a preferred example, the upstream element may have a length of approximately 5 millimetres.

The aerosol-generating article may further comprise a wrapper circumscribing at least one component of the aerosol-generating article. The wrapper may circumscribe the tubular element and at least one other component of the aerosol-generating article. The wrapper may circumscribe the tubular element and at least a part of a component of the aerosol-generating article upstream of the tubular element. The wrapper may circumscribe the tubular element and at least a part of a component of the aerosol-generating article downstream of the tubular element.

In one example, the wrapper may circumscribe the upstream element, the substrate element and the tubular element to form a wrapped subassembly. The wrapped subassembly may be joined to the mouthpiece element by a tipping paper. The tipping paper may circumscribe the mouthpiece element and a downstream portion of the wrapped subassembly.

In another example, the wrapper may circumscribe all components of the aerosolgenerating article. The wrapper may extend along the entire length of the aerosol-generating article, that is, from an upstream end of the aerosol-generating article to a downstream end of the aerosol-generating article.

The wrapper may be an outer wrapper. The wrapper may be the outermost wrapper. The outer surface of the wrapper may form the outer surface of the aerosol-generating article. The wrapper may be porous or be provided with ventilation means, particularly in the region of, or overlying, the ventilation zone.

According to an example of the present disclosure, there is provided an aerosolgenerating article comprising: a substrate element comprising an aerosol-generating substrate; and a tubular element comprising integral first and second tubular portions; wherein the first tubular portion and second tubular portion each constitute at least 10 percent of the length of the tubular element; wherein the first tubular portion has a first internal diameter and the second tubular portion has a second internal diameter, the second internal diameter being greater than the first internal diameter; wherein the first tubular portion comprises an inner tube segment and a first part of an outer tube segment arranged around the inner tube segment, wherein the second tubular portion comprises a second part of the outer tube segment that extends beyond an end of the inner tube segment in a longitudinal direction of the tubular element, the first internal diameter being the internal diameter of the inner tube segment and the second internal diameter being the internal diameter of the second part of the outer tube segment; wherein the inner tube segment and the outer tube segment comprise a plurality of spirally wound substantially continuous strips of a web material.

The example aerosol-generating article immediately above may have any of the features of any of the aforementioned aerosol-generating articles, which features are not repeated here in the interests of conciseness.

In another example aerosol-generating article, the first and second tubular portions may have different first and second external diameters respectively.

The substrate element may comprise a capsule containing an aerosol-generating substrate. The capsule may be arranged upstream of the tubular element. The first external diameter may be less than the second external diameter. The external surface of the first tubular portion of the tubular element having a smaller first external diameter may define, at least in part, an annular space within the aerosol-generating article. Advantageously, the annular space may define a gutter or well that collects excess aerosolgenerating substrate that is released from the capsule. The annular space may also collect aerosol-generating substrate that is released from the capsule when the aerosol-generating article is moved around between consumer inhalations.

The first external diameter may be at least 1 millimetre less than the second external diameter. Optionally, the first external diameter may be at least 2 millimetres less than the second external diameter. Further optionally, the first external diameter may be at least 3 millimetres less than the second external diameter.

The difference between the first and second external diameters may be between about 0.5 and about 3.5 millimetres, optionally between about 1 millimetre and about 3 millimetres and further optionally between about 1.5 millimetres and about 2.5 millimetres. In a preferred example, the difference between the first and second external diameters may be about 2 millimetres.

A ratio between the second external diameter and the first external diameter may be between 1.2 and 1.8, preferably between 1.3 and 1.6 and more preferably between 1.3 and 1.5. In a preferred example, a ratio between the second external diameter and the first external diameter may be about 1 .4.

The first tubular portion may comprise a first part of an inner tube segment. The second tubular portion may comprise a second part of the inner tube segment. The second tubular portion may comprise an outer tube segment arranged around the second part of the inner tube segment. The first external diameter may be the external diameter of the first part of the inner tube segment. The second external diameter may be the external diameter of the outer tube segment.

The outer tube segment may overlap the inner tube segment. The outer tube segment may overlap at least 10 percent of the length of the inner tube segment, preferably at least 20 percent of the length of the inner tube segment, more preferably at least 30 percent of the length of the inner tube segment, and yet more preferably at least 40 percent of the length of the inner tube segment. In a preferred example, the outer tube segment may overlap about 50 percent of the length of the inner tube segment.

The inner tube segment may comprise a plurality of layers of a web material. The inner tube segment may comprise between 1 and 20 layers of the web material. The inner tube segment may comprise a plurality of substantially continuous strips of the web material. The substantially continuous strips may be spirally wound.

The outer tube segment may comprise a plurality of layers of a web material. The outer tube segment may comprise between 1 and 20 layers of the web material. The outer tube segment may comprise a plurality of substantially continuous strips of the web material. The substantially continuous strips may be spirally wound.

The inner tube segment and the outer tube segment may comprise a plurality of spirally wound substantially continuous strips of a web material.

The web material may comprise one or more of paper, cardboard, acetate tow or polylactic acid (PLA).

The width of the substantially continuous strips may be between 10 millimetres and 50 millimetres. The thickness of the web material may be between 0.05 millimetres and 0.1 millimetres.

The tubular element may define an internal cavity that extends from an upstream end of the tubular element to a downstream end of the tubular element. The internal cavity may define an airflow pathway through the tubular element. The internal cavity may be substantially empty to allow substantially unrestricted airflow along the internal cavity.

The first tubular portion of the tubular element may have an external diameter of at least about 4.0 millimetres, preferably at least about 4.5 millimetres, and more preferably at least about 5.0 millimetres. Alternatively or in addition, the first tubular portion of the tubular element may have an external diameter of less than about 7.0 millimetres, preferably less than about 6.5 millimetres or less than about 6.0 millimetres.

The first tubular portion of the tubular element may have an external diameter between about 4.0 millimetres and about 7.0 millimetres, preferably between about 4.0 millimetres and about 6.0 millimetres, and more preferably between about 4.5 millimetres and 5.5 millimetres. In a preferred example, the first tubular portion of the tubular element may have an external diameter of about 5.0 millimetres.

A peripheral wall of the first tubular portion may have a thickness of at least about 0.5 millimetres, preferably at least about 1 .0 millimetre or at least about 2 millimetres. Alternatively or in addition, a peripheral wall of the first tubular portion may have a thickness of less than about 3.0 millimetres, preferably less than about 2.5 millimetres or less than about 2 millimetres.

A peripheral wall of the first tubular portion may have a thickness of between about 0.5 millimetres and 3.0 millimetres, preferably between about 1.0 millimetre and 2.5 millimetres, and more preferably between about 1 .0 millimetre and 2.0 millimetres. In a preferred example, a peripheral wall of the first tubular portion may have a thickness of about 1.0 millimetres.

The first tubular portion of the tubular element may have a length of at least about 3 millimetres, preferably at least about 4 millimetres and more preferably at least about 5 millimetres. The first tubular portion of the tubular element may have a length of less than about 10 millimetres, preferably less than about 8 millimetres and more preferably less than about 7 millimetres.

The first tubular portion of the tubular element may have a length between about 3 millimetres and about 10 millimetres, preferably between about 4 millimetres and 8 millimetres, and more preferably between about 5 millimetres and 7 millimetres. In a preferred example, the first tubular portion of the tubular element may have a length of about 6 millimetres.

The second tubular portion of the tubular element may have an external diameter of at least about 5.0 millimetres, preferably at least about 6.0 millimetres, and more preferably at least about 7.0 millimetres. Alternatively or in addition, the second tubular portion of the tubular element may have an external diameter of less than about 10.0 millimetres, preferably less than about 9.0 millimetres, and more preferably less than about 8.0 millimetres.

The second tubular portion of the tubular element may have an external diameter between about 5.0 millimetres and about 10.0 millimetres, preferably between about 6.0 millimetres and about 9.0 millimetres, and more preferably between about 6.5 millimetres and 8.0 millimetres. In a preferred example, the second tubular portion of the tubular element may have an external diameter of about 7.0 millimetres.

A peripheral wall of the second tubular portion may have a thickness of at least 0.5 millimetres, preferably at least about 1.0 millimetre, and more preferably at least about 1.5 millimetres. Alternatively or in addition, a peripheral wall of the second tubular portion may have a thickness of less than about 3.5 millimetres, preferably less than about 3.0 millimetres, and more preferably less than about 2.5 millimetres.

A peripheral wall of the second tubular portion may have a thickness between about 0.5 millimetres and 3.5 millimetres, preferably between about 1.0 millimetre and 3.0 millimetres, and more preferably between about 1.5 millimetres and 2.5 millimetres. In a preferred example, a peripheral wall of the second tubular portion may have a thickness of about 2.0 millimetres.

The second tubular portion of the tubular element may have a length of at least about 6 millimetres, preferably at least about 7 millimetres and more preferably at least about 8 millimetres. The second tubular portion of the tubular element may have a length of less than about 12 millimetres, preferably less than about 11 millimetres and more preferably less than about 10 millimetres.

The second tubular portion of the tubular element may have a length between about 6 millimetres and about 12 millimetres, preferably between about 7 millimetres and 11 millimetres, and more preferably between about 8 millimetres and 10 millimetres. In a preferred example, the second tubular portion of the tubular element may have a length of about 9 millimetres.

An internal diameter of the tubular element may be less than an external diameter of the capsule. Advantageously, this helps to prevent the capsule from passing through the tubular element, that is, through the internal cavity in the tubular element.

The internal diameter of the tubular element may be at least 1 millimetre less than an external diameter of the capsule. Optionally, the internal diameter of the tubular element may be at least 2 millimetres less than an external diameter of the capsule. Further optionally, the internal diameter of the tubular element may be at least 3 millimetres less than an external diameter of the capsule.

The internal diameter of the tubular element may be uniform over the whole length of the tubular element. The tubular element may have an internal diameter of less than 4.5 millimetres, preferably less than 4.0 millimetres, and more preferably less than 3.5 millimetres.

An upstream end of the tubular element may be arranged to engage an external surface of the capsule. The tubular element may act as a retention plug or element for restricting downstream movement of the capsule. Advantageously, by restricting movement of the capsule, piercing of the capsule to free the contents of the capsule may be made easier by providing a surface to press against.

The aerosol-generating article may comprise a tubular body having a partially-closed distal or upstream end and a partially-closed downstream or mouth end. An upstream opening may be formed in the upstream end of the tubular body. The upstream opening may act as an air inlet. A downstream opening may be formed in the mouth end of the tubular body. The downstream opening may act as an air outlet. An airflow pathway may extend between the upstream opening and the downstream opening and passes through an internal cavity of the tubular body. The second tubular portion of the tubular element may be fixed to an internal surface of the tubular body.

The capsule may contain dry powder. The capsule may hold or contain at least about 5 milligrams of a dry powder or at least about 10 milligrams of a dry powder. The capsule may hold or contain less than or equal to about 900 milligrams of a dry powder, less than or equal to about 30 300 milligrams of a dry powder, or less than or equal to about 150 milligrams of a dry powder. The capsule may hold or contain between about 5 milligrams and about 300 milligrams of dry powder, between about 10 milligrams and about 200 milligrams of dry powder, or between about 25 milligrams and about 100 milligrams of dry powder.

The capsule may contain pharmaceutically active particles, such as nicotine particles. As used herein, the term “nicotine” may refer to nicotine and nicotine derivatives such as free- base nicotine, nicotine salts and the like.

The capsule may comprise one or more nicotine salts.

The pharmaceutically active particles may have a mass median aerodynamic diameter of less than or equal to about 5 micrometres, or less than or equal to about 4 micrometres.

The pharmaceutically active particles may have a mass median aerodynamic diameter of at least about 0.5 micrometres, or at least about 1 micrometre.

The pharmaceutically active particles may have a mass median aerodynamic diameter of between about 0.5 micrometres and about 4 micrometres.

The capsule may contain enough nicotine particles to provide at least 2 inhalations or “puffs”, at least 5 inhalations or “puffs”, or at least 10 inhalations or “puffs”.

Each inhalation or “puff” may deliver from about 0.1 milligrams to about 3 milligrams of nicotine particles to the lungs of the user, from about 0.2 milligrams to about 2 milligrams of nicotine particles to the lungs of the user, or about 1 milligram of nicotine particles to the lungs of the user.

The capsule may hold or contain at least about 5 milligrams of nicotine particles, or at least about 10 milligrams of nicotine particles.

The capsule may hold or contain less than or equal to about 900 milligrams of nicotine particles, less than or equal to about 300 milligrams of nicotine particles, or less than or equal to about 150 milligrams of nicotine particles.

The capsule may contain flavour particles.

According to another example of the present disclosure, there is provided a method of manufacturing a tubular element for an aerosol-generating article. The method may comprise forming an inner tube. The inner tube may be formed from a plurality of layers of a first web material. The method may comprise cutting the inner tube to form a plurality of inner tube segments. The method may comprise feeding the plurality of inner tube segments along a moving delivery path. A predefined space may be provided between successive inner tube segments. The method may comprise wrapping the plurality of inner tube segments in at least one layer of a second web material to form an outer tube around the inner tube segments. The method may comprise cutting the outer tube in a space between the inner tube segments.

According to another example of the present disclosure, there is provided a method of manufacturing a tubular element for an aerosol-generating article. The method comprises: forming an inner tube from a plurality of layers of a first web material; cutting the inner tube to form a plurality of inner tube segments; feeding the plurality of inner tube segments along a moving delivery path, wherein there is a predefined space between successive inner tube segments; wrapping the plurality of inner tube segments in at least one layer of a second web material to form an outer tube around the inner tube segments; cutting the outer tube in a space between the inner tube segments.

Advantageously, by wrapping a plurality of spaced apart inner tube segments in a web material to form an outer tube around the inner tube segments and cutting the outer tube in a space between the inner tube segments, a tubular element can be formed having first and second tubular portions with different internal diameters.

Forming an inner tube may comprise spirally winding a plurality of substantially continuous strips of the first web material.

The plurality of inner tube segments may be wrapped in a plurality of layers of the second web material to form an outer tube around the inner tube segments. The plurality of inner tube segments may be parallel wrapped with the second web material.

According to another example of the present disclosure, there is provided a method of manufacturing a tubular element for an aerosol-generating article. The method may comprise forming an inner tube from a plurality of layers of a first web material. The method may comprise cutting the inner tube to form a plurality of inner tube segments. The method may comprise forming an outer tube from a plurality of layers of a third web material. The outer tube may having an internal diameter that is substantially the same as an external diameter of the inner tube. The method may comprise cutting the outer tube to form a plurality of outer tube segments. The outer tube segments may have a different length to the inner tube segments. The method may comprise inserting the inner tube segments into the outer tube segments. The method may comprise fixing an outer surface of the inner tube segments to an inner surface of the outer tube segments.

According to another example of the present disclosure, there is provided a method of manufacturing a tubular element for an aerosol-generating article. The method comprises: forming an inner tube from a plurality of layers of a first web material; cutting the inner tube to form a plurality of inner tube segments; forming an outer tube from a plurality of layers of a third web material, the outer tube having an internal diameter that is substantially the same as an external diameter of the inner tube; cutting the outer tube to form a plurality of outer tube segments, the outer tube segments having a different length to the inner tube segments; inserting the inner tube segments into the outer tube segments; fixing an outer surface of the inner tube segments to an inner surface of the outer tube segments.

When referring to the internal diameter of the outer tube being substantially the same as the external diameter of the inner tube, the term “substantially the same” is intended to mean that at least one, or possibly both, of these diameters include a suitable tolerance to allow the inner tube to be inserted into the outer tube without having to use excessive force, that is, force that may damage one or other of the inner and outer tube segments.

Advantageously, by forming inner and outer tube segments having different lengths and inserting the inner tube segments into the outer tube segments, a tubular element can be formed having first and second tubular portions with different internal or external diameters.

Forming an outer tube may comprise spirally winding a plurality of substantially continuous strips of the third web material.

Features described in relation to one of the above examples may equally be applied to other examples of the present disclosure.

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

Example Ex1 : An aerosol-generating article comprising: a substrate element comprising an aerosol-generating substrate; and a tubular element comprising first and second tubular portions.

Example Ex2: An aerosol-generating article according to Example Ex1 , wherein the tubular element comprises integral first and second tubular portions.

Example Ex3: An aerosol-generating article according to Example Ex1 or Ex2, wherein the first tubular portion and second tubular portion each constitute at least 10 percent of the length of the tubular element.

Example Ex4: An aerosol-generating article according to any of Examples Ex1 to Ex3, wherein the first tubular portion has a first internal diameter and the second tubular portion has a second internal diameter, the first internal diameter being different to the second internal diameter.

Example Ex5: An aerosol-generating article according to any of Examples Ex1 to Ex3, wherein the first tubular portion has a first external diameter and the second tubular portion has a second external diameter, the first external diameter being different to the second external diameter.

Example Ex6: An aerosol-generating article according to any of Examples Ex2 to Ex5, wherein the first tubular portion and second tubular portion each constitute at least 20 percent of the length of the tubular element. Example Ex7: An aerosol-generating article according to Example Ex6, wherein the first tubular portion and second tubular portion each constitute at least 30 percent of the length of the tubular element.

Example Ex8: An aerosol-generating article according to Example Ex7, wherein the first tubular portion and second tubular portion each constitute at least 40 percent of the length of the tubular element.

Example Ex9: An aerosol-generating article according to any of Examples Ex2 to Ex8, wherein the first tubular portion and second tubular portion each constitute about 50 percent of the length of the tubular element.

Example Ex10: An aerosol-generating article according to any preceding example, wherein the differences in internal or external diameters are formed by a step in the internal or external surface of the tubular element.

Example Ex11 : An aerosol-generating article according to any preceding example, wherein the differences in internal or external diameters are at least 1 millimetre.

Example Ex12: An aerosol-generating article according to Example Ex11 , wherein the differences in internal or external diameters are at least 2 millimetres.

Example Ex13: An aerosol-generating article according to Example Ex12, wherein the differences in internal or external diameters are at least 2.5 millimetres.

Example Ex14: An aerosol-generating article according to any preceding example, wherein the first and second tubular portions have different first and second internal diameters respectively.

Example Ex15: An aerosol-generating article according to Example Ex14, wherein the second internal diameter is greater than the first internal diameter.

Example Ex16: An aerosol-generating article according to Example Ex15, wherein a ratio of the second internal diameter to the first internal diameter is between 1.2 and 1 .8.

Example Ex17: An aerosol-generating article according to Example Ex16, wherein a ratio of the second internal diameter to the first internal diameter is between 1.3 and 1 .7.

Example Ex18: An aerosol-generating article according to Example Ex17, wherein a ratio of the second internal diameter to the first internal diameter is between 1.4 and 1.6.

Example Ex19: An aerosol-generating article according to Example Ex29, wherein a ratio of the second internal diameter to the first internal diameter is about 1 .4.

Example Ex20: An aerosol-generating article according to any preceding example, wherein the first tubular portion comprises an inner tube segment and a first part of an outer tube segment arranged around the inner tube segment, the first internal diameter being the internal diameter of the inner tube segment.

Example Ex21 : An aerosol-generating article according to Example Ex20, wherein the second tubular portion comprises a second part of the outer tube segment that extends beyond an end of the inner tube segment in a longitudinal direction of the tubular element, the second internal diameter being the internal diameter of the second part of the outer tube segment.

Example Ex22: An aerosol-generating article according to Example Ex20 or Ex21 , wherein the inner tube segment comprises a plurality of layers of a first web material.

Example Ex23: An aerosol-generating article according to Example Ex22, wherein the inner tube segment comprises between 1 and 20 layers of the first web material.

Example Ex24: An aerosol-generating article according to Example Ex22 or Ex23, wherein the inner tube segment comprises a plurality of substantially continuous strips of the first web material.

Example Ex25: An aerosol-generating article according to Example Ex24, wherein the substantially continuous strips are spirally wound.

Example Ex26: An aerosol-generating article according to any of Examples Ex22 to Ex25, wherein the first web material comprises one or more of paper, cardboard, acetate tow or polylactic acid.

Example Ex27: An aerosol-generating article according to any of Examples Ex22 to Ex26, wherein the thickness of the first web material is between 0.05 millimetres and 0.1 millimetres.

Example Ex28: An aerosol-generating article according to any of Examples Ex21 to Ex27, wherein the outer tube segment comprises one or more layers of a second web material.

Example Ex29: An aerosol-generating article according to Example Ex28, wherein the second web material is parallel wrapped around the inner tube segment.

Example Ex30: An aerosol-generating article according to Example Ex29, wherein the outer tube segment comprises a plurality of layers of the second web material parallel wrapped around the inner tube segment.

Example Ex31 : An aerosol-generating article according to Example Ex30, wherein the outer tube segment comprises between 1 and 20 layers of the second web material.

Example Ex32: An aerosol-generating article according to any of Examples Ex28 to Ex31 , wherein the second web material comprises one or more of paper, cardboard, acetate tow or polylactic acid.

Example Ex33: An aerosol-generating article according to any of Examples Ex28 to Ex32, wherein the thickness of the second web material is between 0.05 millimetres and 1.1 millimetres.

Example Ex34: An aerosol-generating article according to any preceding example, further comprising a ventilation zone provided at a position along the second tubular portion. Example Ex35: An aerosol-generating article according to Example Ex34, wherein the ventilation zone comprises a plurality of ventilation holes through the peripheral wall of the second tubular portion.

Example Ex36: An aerosol-generating article according to Example Ex34 or Ex35, wherein the aerosol-generating article has a ventilation level of about 30 percent.

Example Ex37: An aerosol-generating article according to any preceding example, wherein the substrate element is arranged upstream of the tubular element.

Example Ex38: An aerosol-generating article according to any preceding example, wherein the substrate element abuts the tubular element.

Example Ex40: An aerosol-generating article according to any preceding example, wherein the substrate element comprises a susceptor.

Example Ex41 : An aerosol-generating article according to any of Examples Ex1 to Ex13, wherein the first and second tubular portions have different first and second external diameters respectively.

Example Ex42: An aerosol-generating article according to Example Ex41 , wherein the substrate element comprises a capsule containing an aerosol-generating substrate.

Example Ex43: An aerosol-generating article according to Example Ex41 or Ex42, wherein the first external diameter is less than the second external diameter.

Example Ex44: An aerosol-generating article according to any of Examples Ex41 to Ex43, wherein a ratio between the second external diameter and the first external diameter is between 1 .2 and 1 .8.

Example Ex45: An aerosol-generating article according to Example Ex44, wherein a ratio between the second external diameter and the first external diameter is between 1.3 and 1.6.

Example Ex46: An aerosol-generating article according to Example Ex45, wherein a ratio between the second external diameter and the first external diameter is between 1.3 and 1.5.

Example Ex47: An aerosol-generating article according to Example Ex46, wherein a ratio between the second external diameter and the first external diameter is about 1 .4.

Example Ex48: An aerosol-generating article according to any of Examples Ex41 to Ex47, wherein the first tubular portion comprises a first part of an inner tube segment, the first external diameter being the external diameter of the first part of the inner tube segment.

Example Ex49: An aerosol-generating article according to Example Ex46, wherein the second tubular portion comprises a second part of the inner tube segment and an outer tube segment arranged around the second part of the inner tube segment, the second external diameter being the external diameter of the outer tube segment. Example Ex50: An aerosol-generating article according to Example Ex48 or Ex49, wherein the inner tube segment comprises a plurality of spirally wound substantially continuous strips of a web material.

Example Ex51 : An aerosol-generating article according to any of Examples Ex48 to Ex50, wherein the outer tube segment comprises a plurality of spirally wound substantially continuous strips of a web material.

Example Ex52: An aerosol-generating article according to any of Examples Ex41 to Ex51 , wherein an internal diameter of the tubular element is less than an external diameter of the capsule.

Example Ex53: A method of manufacturing a tubular element for an aerosol-generating article, the method comprising: forming an inner tube from a plurality of layers of a first web material; cutting the inner tube to form a plurality of inner tube segments; feeding the plurality of inner tube segments along a moving delivery path, wherein there is a predefined space between successive inner tube segments; wrapping the plurality of inner tube segments in at least one layer of a second web material to form an outer tube around the inner tube segments; cutting the outer tube in a space between the inner tube segments.

Example Ex54: A method according to Example Ex53, wherein forming an inner tube comprises spirally winding a plurality of substantially continuous strips of the first web material.

Example Ex55: A method according to Example Ex53 or Ex54, wherein the plurality of inner tube segments are wrapped in a plurality of layers of the second web material to form an outer tube around the inner tube segments.

Example Ex56: A method according to any of Examples Ex53 to Ex55, wherein the plurality of inner tube segments are parallel wrapped with the second web material.

Example Ex57: A method of manufacturing a tubular element for an aerosol-generating article, the method comprisiong: forming an inner tube from a plurality of layers of a first web material; cutting the inner tube to form a plurality of inner tube segments; forming an outer tube from a plurality of layers of a third web material, the outer tube having an internal diameter that is substantially the same as an external diameter of the inner tube; cutting the outer tube to form a plurality of outer tube segments, the outer tube segments having a different length to the inner tube segments; inserting the inner tube segments into the outer tube segments; fixing an outer surface of the inner tube segments to an inner surface of the outer tube segments.

Example Ex58: A method according to Example Ex57, wherein forming an inner tube comprises spirally winding a plurality of substantially continuous strips of the first web material.

Example Ex59: A method according to Example Ex57 or Ex58, wherein forming an outer tube comprises spirally winding a plurality of substantially continuous strips of the third web material.

Examples will now be further described with reference to the figures in which:

Figure 1 is a schematic longitudinal cross-sectional view of an aerosol-generating article.

Figure 1 A is a schematic longitudinal cross-sectional view of the tubular element of the aerosol-generating article of Figure 1 showing this feature in more detail.

Figure 2 is a schematic longitudinal cross-sectional view of another aerosol-generating article.

Figure 2A is a schematic longitudinal cross-sectional view of the tubular element of the aerosol-generating article of Figure 2 showing this feature in more detail.

Figure 3 is flow chart of a method for manufacturing a tubular element for an aerosolgenerating article.

Figure 4 is a schematic side view of an apparatus for forming a tube from a substantially continuous strip of web material being spirally wound around a mandrel.

Figure 5 is a schematic side view of an apparatus for forming a tube from a plurality of substantially continuous strips of web material being spirally wound around a mandrel.

Figure 6 is a schematic perspective view of another apparatus for forming a tube by spirally winding a plurality of substantially continuous strips of web material.

Figure 7 is a schematic side view of an apparatus for parallel wrapping inner tube segments in a web material to form a substantially continuous outer tube and cutting the outer tube to a predetermined size.

Figure 7A is a schematic side view showing the spaced apart arrangement between inner tube segments as they are fed into the apparatus of Figure 7.

Figures 8A to 8D are schematic transverse cross-sectional views of the preforming, gluing, compressing and drying devices respectively used in the apparatus of Figure 7.

Figure 9 is a schematic side view showing the locations at which the substantially continuous outer tube comprising inner tube segments is cut by the cutter of the apparatus of Figure 7 to form individual tubular elements.

Figure 10A is a schematic view of an apparatus for parallel wrapping multiple layers of web material around inner tube segments.

Figure 10B is a schematic cross-sectional side view of an outer tube subassembly produced by the apparatus of Figure 10A showing the locations of successive cuts.

Figure 10C is a schematic cross-sectional side view showing an outer tube subassembly produced by the apparatus of Figure 10A after ten passes through the apparatus of Figure 10A.

Figure 10D is a schematic cross-sectional view of a spirally wound inner tube segment. Figure 10E is a schematic cross-sectional view of an outer tube segment added to the inner tube segment of Figure 10D after ten passes through the apparatus of Figure 10A.

Figure 11 is flow chart of another method for manufacturing a tubular element for an aerosol-generating article.

Figures 12A and 12B are schematic longitudinal cross-sectional views of a tubular element in which an inner tube segment is inserted into an outer tube segment in a disassembled state and an assembled state respectively.

Figure 12C shows a rotating nozzle being used to apply an adhesive to an inner surface of the outer tube segment of the tubular element of Figures 12A and 12B.

Figure 12D shows the tubular element of Figures 12A and 12B in an assembled state and an enlarged view of the adhesive bond between the inner and outer tube segments.

Figure 13 shows an apparatus for assembling the tubular element of Figures 12A and 12B.

Figure 14 is schematic longitudinal cross-sectional view of another tubular element in which an inner tube segment is inserted into an outer tube segment.

Referring to Figure 1 , there is shown an aerosol-generating article 1 comprising a plurality of elements assembled in the form of a rod. The aerosol-generating article 1 comprises a substrate element 2 containing aerosol-generating substrate and a downstream section 4 at a location downstream of the substrate element 2. Further, the aerosol-generating article 1 comprises an upstream section 6 at a location upstream of the substrate element 2. The aerosol-generating article 1 extends from an upstream or distal end 8 to a downstream or mouth end 10. The aerosol-generating article has an overall length of about 45 millimetres.

The downstream section 4 comprises a tubular element 12 located immediately downstream of the substrate element 2, the tubular element 12 being in longitudinal alignment with the substrate element 2. In the example of Figure 1 , the upstream end of the tubular element 12 abuts the downstream end of the substrate element 2. The tubular element 12 comprises a first tubular portion 14 and a second tubular portion 16, the second tubular portion 16 being downstream of the first tubular portion 14. The first 14 and second 16 tubular portions are integral to the tubular element 12. That is, the first 14 and second 16 tubular portions each form part of the tubular element 12 rather than being separate components. Therefore, tubular element 12 comprising the first 14 and second 16 tubular portions is a single component of the aerosol-generating article 1 .

The first tubular portion 14 of the tubular element 12 defines an internal cavity 18 that extends all the way from an upstream end 20 of the first tubular portion 14 to a downstream end 22 of the first tubular portion 14. The internal cavity 18 is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity 18. Therefore, the first tubular portion 14 does not substantially contribute to the overall RTD of the aerosolgenerating article 1. In more detail, the RTD of the first tubular portion 14 is substantially 0 millimetres H2O. The first tubular portion 14 of the tubular element 12 is configured to act as a spacer or support element for the aerosol-generating article 1.

The second tubular portion 16 of the tubular element 12 defines an internal cavity 24 that extends all the way from an upstream end 22 of the second tubular portion 16 to a downstream end 26 of the second tubular portion 16. The internal cavity 24 is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity 24. The second tubular portion does not substantially contribute to the overall RTD of the aerosolgenerating article 10. In more detail, the RTD of the second tubular portion 16 is substantially 0 millimetres H2O. The second tubular portion 16 of the tubular element 12 is configured to act as an aerosol-cooling element for the aerosol-generating article 1 .

The aerosol-generating article 1 further comprises a ventilation zone 28 provided at a location along the second tubular portion 16 of the tubular element 12. In more detail, the ventilation zone 28 is provided at about 2 millimetres from the upstream end 22 of the second tubular portion 16. The ventilation zone 28 comprises a circumferential ring of perforations or ventilation holes extending through the wall of the second tubular portion 16 . Air may be drawn through the ventilation holes and through the second tubular portion 16 to achieve cooling of the stream of aerosol generated upon heating of the substrate element 2. A ventilation level of the aerosol-generating article 1 is about 25 percent.

In the example of Figure 1 , the downstream section 4 further comprises a mouthpiece element 30 at a location downstream of the tubular element 12. In more detail, the mouthpiece element 30 is positioned immediately downstream of the second tubular portion 16 of the tubular element 12. An upstream end of the mouthpiece element 30 abuts the downstream end 26 of the second tubular portion 16 of the tubular element 12. The mouthpiece element 30 is provided in the form of a cylindrical plug of low-density cellulose acetate. The mouthpiece element 30 further comprises a wrapper or plug wrap 35 circumscribing the aerosol-generating substrate. The mouthpiece element 30 has a length of about 12 millimetres and an external diameter of about 7.1 millimetres.

The substrate element 2 comprises an aerosol-generating substrate of one of the types described above. The substrate element 2 is in the form of a rod comprising the aerosolgenerating substrate. The aerosol-generating substate may substantially define the structure and dimensions of the rod 2. The rod 2 may further comprise a wrapper (not shown) circumscribing the aerosol-generating substrate. The substrate element 2 has an external diameter of about 7.1 millimetres and a length of about 12 millimetres. However, it will be appreciated that these dimensions can vary. For example, in another aerosol-generating article the substrate element 2 may have a length of about 11 millimetres.

The aerosol-generating article 1 further comprises an elongate susceptor element 32 within the substrate element 2. In more detail, the susceptor element 32 is arranged substantially longitudinally within the aerosol-generating substrate, such as to be approximately parallel to the longitudinal direction of the rod-shaped substrate element 2. The susceptor element 32 is positioned in a radially central position within the substrate element 2 and extends effectively along the longitudinal axis of the substrate element 2. The susceptor element 32 extends all the way from an upstream end to a downstream end of the substrate element 2. In effect, the susceptor element 32 has substantially the same length as the substrate element 2. In the example of Figure 1 , the susceptor element 32 is provided in the form of a strip and has a length of about 12 millimetres, a thickness of about 60 micrometres, and a width of about 4 millimetres.

The upstream section 6 comprises an upstream element 34 located immediately upstream of the substrate element 2, the upstream element 34 being in longitudinal alignment with the substrate element 2. In the example of Figure 1 , the downstream end of the upstream element 34 abuts the upstream end of the substrate element 2. This advantageously prevents the susceptor element 44 from being dislodged. Further, this ensures that the consumer cannot accidentally contact the heated susceptor element 34 after use. The upstream element 34 is provided in the form of a cylindrical plug of cellulose acetate circumscribed by a stiff wrapper (not shown). The upstream element 34 has a length of about 5 millimetres.

The aerosol-generating article 1 further comprises a wrapper 36 circumscribing the upstream element 34, the substrate element 2 and the tubular element 12. The wrapper 36 extends from the upstream or distal end 8 of the aerosol-generating article 1 to the downstream end 26 of the second tubular portion 16. The ventilation holes of the ventilation zone 28 extend through the wrapper 36 to communication with the ventilation holes in the tubular element 12. The mouthpiece element 30 is joined to the aerosol-generating article 1 by a tipping paper 37 that circumscribes the mouthpiece element 30 and a part of the downstream end of the second tubular portion 16 that is wrapped in wrapper 36.

Figure 1 A shows the tubular element 12 of the aerosol-generating article 1 of Figure 1 in more detail. The first tubular portion 14 has a length L1 of about 8 millimetres and the second tubular portion 16 has a length L2 of about 8 millimetres. Therefore, the first tubular portion 14 and second tubular portion 16 each constitute about 50 percent of the overall length (L1 + L2) of the tubular element 12, which is about 16 millimetres. However, it will be appreciated that these lengths, and their relative percentages, can vary. For example, in another aerosol-generating article the second tubular portion may have a length of 9 millimetres. The first tubular portion 14 and second tubular portion 16 have the same external diameter D_ext of about 7.1 millimetres, which is constant over the whole length (L1 + L2) of the tubular element 12. The first tubular portion 14 and second tubular portion 16 have different internal diameters. The first tubular portion 14 has a first internal diameter D 1 _int of about 3.3 millimetres. Thus, a thickness of a peripheral wall of the first tubular portion 14 is about 1 .9 millimetres. The second tubular portion 16 has a second internal diameter D2j_nt of about 5.0 millimetres. Thus, a thickness of a peripheral wall of the second tubular portion 16 is about 1.05 millimetres. The first internal diameter D1 _int of the first tubular portion 14 is uniform over the length L1 of the first tubular portion 14 and the second internal diameter D2j_nt of the second tubular portion 16 is uniform over the length L2 of the second tubular portion 16. A ratio between the second internal diameter D2j_nt of the second tubular portion 16 and the first internal diameter D1 _int of the first tubular portion 14 is about 1.52.

The tubular element 12 comprises an inner tube segment 15 and an outer tube segment 17 that surrounds the inner tube segment 15. The inner tube segment 15 has a length L1 equal to that of the first tubular portion 14. The thickness of the peripheral wall of the inner tube segment 15 is 0.85 millimetres. The outer tube segment 17 is longer than the inner tube segment 15 such that it extends beyond the downstream end 22 of the inner tube segment 15 by the length of the second tubular portion L2. The outer tube segment 17 extends from an upstream end 20 of the tubular element 12 to a downstream end 26 of the tubular element 12. The thickness of the peripheral wall of the outer tube segment 17 is 1.05 millimetres. Therefore, the first tubular portion 14 of the tubular element 12 comprises the inner tube segment 15 and a first part of an outer tube segment 17 defined by the length L1 arranged around the inner tube segment 15. The radial thickness of the first tubular portion 14 is equal to the combined thickness of the peripheral walls of the inner 15 and outer 17 tube segments, which as discussed above is 1.9 millimetres. The second tubular portion 16 comprises a second part of the outer tube segment 16 that extends beyond the downstream end 22 of the inner tube segment 15 in a longitudinal direction of the tubular element 12. The radial thickness of the second tubular portion 16 is equal to the thickness of the peripheral wall of the outer tube segment 17. The first internal diameter D1 _int is the internal diameter of the inner tube segment 15 and the second internal diameter D2j_nt is the internal diameter of the second part of the outer tube segment 17. The external diameter of the inner tube segment 15 is substantially the same as the internal diameter of the outer tube segment 17, that is, the second internal diameter D2j_nt.

The inner tube segment 15 of the tubular element 12 of Figure 1A comprises a plurality of layers of a first web material. In particular, the inner tube segment 15 comprises a plurality of substantially continuous strips of the first web material, which are spirally wound using a method further described below. The outer tube segment 17 of the tubular element 12 of Figure 1A comprises one or more sheets of a second web material, which is or are parallel wrapped around the inner tube segment 15 using a method further described below.

Figure 2 is a schematic longitudinal cross-sectional view of another aerosol-generating article 100. The aerosol-generating article 100 is an inhaler article such as a dry powder inhaler. The aerosol-generating article 100 comprises a tubular body 102 having a partially- closed distal or upstream end 104 and a partially-closed downstream or mouth end 106. An upstream opening 108 is formed in the upstream end 104 of the tubular body 102 and a downstream opening 110 is formed in the mouth end 106 of the tubular body 102. The upstream opening 108 acts as an air inlet and the downstream opening 110 acts as an air outlet. An airflow pathway extends between the upstream opening 108 and the downstream opening 110 and passes through an interior cavity 107 of the tubular body 102. An upstream portion 109 of the interior cavity of the tubular body 102 near the upstream end 104 houses a capsule 111 containing nicotine particles.

The partially closed upstream end 104 of the tubular body 102 prevents the capsule 111 from falling out of the upstream end 104 of the tubular body 102. The diameter of the capsule 111 is larger than the diameter of the upstream opening 108 and therefore cannot pass through the upstream opening 108. A tubular element 112 is provided downstream of the capsule 111. The tubular element 112 is fixed to an internal surface of the tubular body 102 and acts as a retention plug for restricting downstream movement of the capsule 111 to maintain the capsule 111 in an upstream region of the tubular body 102.

The tubular element 112 comprises a first tubular portion 114 and a second tubular portion 116, the second tubular portion 116 being downstream of the first tubular portion 114. The first 114 and second 116 tubular portions are integral to the tubular element 112. That is, the first 114 and second 116 tubular portions each form part of the tubular element 112 rather than being separate components. Therefore, tubular element 112 comprising the first 114 and second 116 tubular portions is a single component of the aerosol-generating article 100.

The first tubular portion 114 has a first external diameter that is less than an internal diameter of the tubular body 102. The second tubular portion 116 has a second external diameter that is substantially the same as the internal diameter of the tubular body 102. Thus, the first external diameter of the first tubular portion 114 is different to the second external diameter of the second tubular portion 116, in particular, the first external diameter is less than the second external diameter. The tubular element is fixed to the internal surface of the tubular body 102 in the region of the second tubular portion 116.

The tubular element 112 defines an internal cavity 118 that extends all the way from an upstream end of the tubular element 112 to a downstream end of the tubular element 112. The internal cavity 118 is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity 118. The internal diameter of the internal cavity 118 is less than an external diameter of the capsule 111 and therefore the capsule is prevented from passing through the tubular element 112.

In use, a consumer pierces the capsule 111 via the upstream opening 108 using an external piercing tool 120 (shown in dashed outline in Figure 2). The piercing tool 120 is pushed through the upstream opening 108 and into the capsule 111 to create a hole 122 in the capsule 111 via which nicotine particles can exit the capsule 111 . Substantial downstream movement of the capsule 111 is limited by the tubular element 112. An upstream end of the tubular element 112 comes into abutting contact with the capsule 111 during piercing and holds the capsule 111 in position to allow for easier piercing.

When a consumer inhales or draws on the mouth end 106 of the aerosolgenerating article 100, air is drawn in through the upstream opening 108 and through the upstream portion 109 of the internal cavity 107 of the tubular body 102 housing the capsule 111. Nicotines particles exit the capsule and are entrained in the airflow through the tubular body 102. The airflow laden with nicotine particles passes through the internal cavity 118 of the tubular element 112 and enters a downstream portion 124 of the internal cavity 107 of the tubular body 102. The internal diameter of the downstream portion 124 of the internal cavity 107 of the tubular body 102 is larger than the internal diameter of the internal cavity 118 of the tubular element 112. The expansion in cross-section of the airflow pathway as air passes from the tubular element 112 into the downstream portion 124 of the internal cavity 107 of the tubular body 102 causes a swirling effect which helps to mix the nicotine particles with the airflow before being drawn into the consumer’s mouth via the downstream opening 110.

The smaller first external diameter of the first tubular portion 114 of the tubular element 112 defines an annular space 126 between an external surface of the first tubular portion 114 and an internal surface of the tubular body 102. The annular space 126 defines a gutter or well that collects excess nicotine particles that are released from the capsule 111 but are not entrained in the airflow when a consumer draws on the aerosol-generating article 100. The annular space 126 also collects nicotine particles that are released from the capsule when the aerosol-generating article 100 is moved around between consumer inhalations. The annular space 126 created by the tubular element 112 acts as a barrier that reduces the likelihood of the nicotine particles leaking from the aerosol-generating article 100 between consumer inhalations or between uses of the aerosol-generating article 100.

Figure 2A shows the tubular element 112 of the aerosol-generating article 100 of Figure 2 in more detail. The first tubular portion 114 has a length L1 of about 6 millimetres and the second tubular portion 116 has a length L2 of about 9 millimetres. Therefore, the first tubular portion 114 and second tubular portion 116 each constitute about 50 percent of the overall length (L1 + L2) of the tubular element 112. However, it will be appreciated that these lengths, and their relative percentages, can vary.

The first tubular portion 114 and second tubular portion 116 have the same internal diameter Dint of about 3.0 millimetres, which is constant over the whole length (L1 + L2) of the tubular element 112. The first tubular portion 114 and second tubular portion 116 have different external diameters. The first tubular portion 114 has a first external diameter D1_ext of about 5.0 millimetres. Thus, a thickness of a peripheral wall of the first tubular portion 114 is about 1.0 millimetres. The second tubular portion 116 has a second external diameter D2_ext of about 7.0 millimetres. Thus, a thickness of a peripheral wall of the second tubular portion 16 is about 2.0 millimetres. The first external diameter D1_ext of the first tubular portion 114 is uniform over the length L1 of the first tubular portion 114 and the second external diameter D2_ext of the second tubular portion 116 is uniform over the length L2 of the second tubular portion 116. A ratio between the second external diameter D2_ext of the second tubular portion 116 and the first external diameter D1_ext of the first tubular portion 114 is about 1.4.

The tubular element 112 comprises an inner tube segment 115 and an outer tube segment 117 that surrounds part of the inner tube segment 115. The inner tube segment 115 extends from an upstream end 119 of the tubular element 112 to a downstream end 121 of the tubular element 112. The inner tube segment 115 has a length L1+L2 equal to the combined lengths of the first 114 and second 116 tubular portions. The outer tube segment 117 has a length L2 and is thus shorter than the inner tube segment 115. The outer tube segment 117 is arranged at the downstream end 121 of the tubular element 112. Therefore, an upstream portion of the inner tube segment 115 that defines the first tubular portion 114 protrudes from the outer tube segment 117. Therefore, the first tubular portion 114 of the tubular element 112 comprises a first part of the inner tube segment 115 defined by the length L1. The second tubular portion 116 comprises a second part of the inner tube segment defined by the length L2 and the outer tube segment 117 arranged around the second part of the inner tube segment 115. The first external diameter D1_ext is the external diameter of the first part of the inner tube segment 115 and the second external diameter D2_ext is the external diameter of the outer tube segment 117. The external diameter of the inner tube segment 115, that is, the first external diameter D1_ext, is substantially the same as the internal diameter of the outer tube segment 117.

The inner 115 and outer 117 tube segments of the tubular element 112 of Figure 2A comprises a plurality of layers of a web material. In particular, the inner 115 and outer 117 tube segments comprise a plurality of substantially continuous strips of the web material, which are spirally wound using a method further described below. Figure 3 shows a flow chart of a method for manufacturing a tubular element for an aerosol-generating article, for example, the tubular element 12 of Figure 1A. The method comprises a first step S1 of forming a substantially continuous inner tube from a plurality of layers of a first web material using a spiral winding process described further below.

In a second step S2, the method comprises cutting the substantially continuous inner tube to form a plurality of inner tube segments. The inner tube segments will extend the whole length of the first tubular portion of the tubular element. In the method of Figure 3, the inner tube segments are cut as double-length inner tube segments, that is, the inner tube segments have twice the length of the first tubular portion. The double-length inner tube segments will undergo a further cutting step to cut them to their final intended size. It will be appreciated that in other example methods, the inner tube segments could be cut as single-length inner tube segments, that is, the inner tube segments have the same length as the first tubular portion.

In a third step S3, the method comprises feeding the plurality of inner tube segments along a moving delivery path, for example, a conveyor belt or other moving means. The inner tube segments are fed on to the moving delivery path with their longitudinal axes aligned. A predefined space is provided between successive inner tube segments. In the method of Figure 3, the inner tube segments are double-spaced, that is, the predefined space between the inner tube segments is twice the length of the second tubular portion of the tubular element. It will be appreciated that in other example methods, the inner tube segments could be singlespaced, that is, the predefined space between inner tube segments could be equal to the length of the second tubular portion of the tubular element.

In a fourth step S4, the method comprises wrapping the plurality of inner tube segments in at least one layer of a second web material to form a substantially continuous outer tube around the inner tube segments. The second web material is wrapped around the inner tube segments using a parallel wrapping method described further below.

In a fifth step S5, the method comprises cutting the outer tube in a space between the inner tube segments. In the case where the method uses double-length inner tube segments that are double spaced, the outer tube is cut at the midpoint of each space between the inner tube segments and the outer tube wrapped inner tube segments are cut at the mid-point of each double-length inner tube segment in order to form individual tubular elements. In the case where the method uses single-length inner tube segments that are single space, the outer tube is cut in the space between the inner tube segments immediately following each inner tube segment in order to form individual tubular elements.

Figure 4 shows a schematic side view of an apparatus 200 for forming a tube 240 from substantially continuous strip of web material 241 being spirally wound around a mandrel 245. Figure 4 shows just one strip of web material in order to illustrate the basis principle. However, it will be appreciated that this principle can be expanded to multiple strips of web material in order to produce thicker tubes, as described below with respect to Figure 5. It will also be appreciated that the strip of web material 241 is substantially continuous, that is, its length is much longer than illustrated in Figure 4. The strip of web material 241 will generally be stored on a reel or bobbin (not shown). The substantially continuous strip of web material 241 will be unwound from the reel and guided to the mandrel by one or more alignment and tensioning rollers (not shown).

The mandrel is an elongate, straight bar or tube having a uniform external diameter over its entire length that defines the internal diameter of the formed tube 240. The strip of web material 241 is fed to the mandrel at an angle a relative to the longitudinal axis of the mandrel 245. The angle a of the strip of web material 241 as well as the pitch of the spiral formed are chosen so that the strip of web material 241 does not overlap itself once wound but follows a helical side-by-side trajectory, such that the opposing side edges of the strip of web material are arranged adjacent to each other, or abut each other, once wound. A side cross-sectional view 246 of the top of the tube 240 is provided above the mandrel 245 in Figure 4 to illustrate the side-by-side arrangement of the successive turns of the strip of web material 241 . Determination of the incoming angle a is described below in more detail with respect to Figure 5.

Figure 5 shows a schematic side view of an apparatus 300 for forming a tube 340 from a plurality of substantially continuous strips of web material 341a to 341 d being spirally wound around a mandrel 345. The apparatus 300 of Figure 5 is similar to apparatus 200 of Figure 4 but instead of using a single strip of web material as in Figure 4, apparatus 300 of Figure 5 forms the tube 340 from a plurality of substantially continuous strips of web material 341a to 341 d. The apparatus 300 and associated method of Figure 5 can be used to form either an inner tube segment or an outer tube segment of a tubular element of an aerosol-generating article.

Each of the plurality of strips of web material 341a to 341 d has the same width and is fed to the mandrel 345 at an angle a relative to the longitudinal axis of the mandrel 345. The angle a of each of the plurality of strips of web material 241 as well as the pitch of the spiral formed by each strip are chosen so that each strip of web material 241 does not overlap itself once wound but follows a helical side-by-side trajectory, as in Figure 4. The plurality of strips of web material 341a to 341 d are fed to the bottom of the mandrel. The strip of web material 341 is uppermost and forms an innermost layer of the tube 340. The strips of web material 341 b to 341 d are arranged successively below the strip 341a in a partially overlapping manner and form further partially overlapping layers of the tube 340. A side cross-sectional view 346 of the top of the tube 340 is provided above the mandrel 345 in Figure 5 and shows the plurality of strips of web material 341a to 341d forming successive overlapping layers of the tube 340. Strip 341a forms an innermost layer and strip 341 d forms an outermost layer. The overlapping strips of web material 341a to 341 d help to strengthen the tube 340 with the overlapping portions of the outer strips 341b to 341 d reinforcing the points of the tube 340 where the side edges of the strips 341a to 341 d are adjoined.

It will be appreciated that the strips of web material 341a to 341 d are substantially continuous, that is, their lengths are much longer than illustrated in Figure 5. Each of the strips of web material 341a to 341 d will generally be stored on its own reel or bobbin (not shown). The substantially continuous strips of web material 341a to 341 d will be unwound from the reels and guided to the mandrel by one or more respective alignment and tensioning rollers (not shown). Although Figure 5 shows a bend in the strips 341b to 341d, this has been down purely to clarify the illustration. Although Figure 5 only shows four strips of web material 341a to 341 d, it will be appreciated that any suitable number of strips could be used and that the number of strips determines the particular thickness of the tube 340.

In the example of Figure 5, the innermost strip of web material 341a has no adhesive coating, while the other strips of web material 341 b to 341 d have an adhesive coating 347 that covers here substantially the entirety of their inner surface. The outer surface of the strips 341 b to 341 d is not coated with adhesive. It will be appreciated that other gluing or adhesive arrangements could be used. For example, the surface of the strips of web material could only be partially coated with adhesive. Furthermore, the outer surfaces of inner strips 341a to 341c could instead be coated with adhesive.

A fast acting glue such as ethylene-vinyl acetate (EVA) glue could be used to coat the strips of web material 341a to 341 d. An advantage of a fast acting glue is that the strips are fixed in a tubular shape during the spiral winding process. A slower acting glue, such as polyvinyl acetate (PVA) could also be used either alone or in combination with EVA. PVA reaches full strength once dried and so it is preferable to have a dryer station downstream of the winding process. The glue is preferably a liquid glue that is applied via a glue roller or by glue nozzles.

The incoming angle a of the strips of web material 341a to 341 d depends on the strip width and thickness, the mandrel diameter and the order of a particular strip in the plurality of strips 341a to 341 d fed to the mandrel. The angle a used for the strips 341a to 341 d should be such that each strip can make a full circle when wound around the mandrel, or around the mandrel and underlying strips, and produce a side-to-side arrangement with itself, that is, the opposing side edges of each strip of web material are arranged adjacent to each other, or abut each other, once wound, as shown in cross-section 346. In other words, the pitch of a helical full turn of a strip around the mandrel should be equal to the width of the strip.

The incoming angle a for the innermost strip wound on the mandrel can be calculated as follows: pitch tan(oc) = — — n^U Equation (1) where pitch is equal to the width of the strip, D is the internal diameter of the tube and TTD is the internal circumference of the tube, which is equal to the external circumference of the mandrel in this case.

Therefore, applying equation 1 for a tube 340 of internal diameter 5 millimetres, which is wound on a mandrel having a 5 millimetre external diameter, and for strip of web material having a width of 10 millimetres, the incoming angle a for the innermost strip, i.e. strip 341a in Figure 5, can be determined as follows:

So, the angle a is equal to 32.5 degrees.

For successive strips forming successive layers of the tube, the winding diameter of the mandrel needs to account for underlying layers already wound. For example, if we use a standard 80 grams per square metre (gsm) uncoated paper which thickness is about 100 micrometres, for the second strip making the second layer, i.e. strip 341 b in Figure 5, the circumference for the mandrel of diameter 5 millimetres will be calculated for a diameter of 5.1 millimetres, that is, the external diameter of the mandrel plus the thickness of the first layer 341a.

In more general terms, the incoming angle a for successive strips wound on the mandrel can be calculated as follows:

Equation (2) where W and T are the width and thickness of the strip of web material respectively, D the internal diameter of the tube or external diameter of the mandrel and N is the order of the strip of web material in the plurality of strips, with N=1 denoting the innermost strip. Therefore, applying equation 2 for a tube of internal diameter 5 millimetres, a strip of web material of width 10 millimetres and thickness 100 micrometres, the fourth strip, that is, strip 341 d in Figure 5, will have an incoming angle a equal to:

So, the angle a for the fourth strip is equal to 31.0 degrees.

As the tube 340 is formed by winding the strips of web material 341a to 341 d around one end of the mandrel 345, it extends in length and advances towards the other end (not shown) of the mandrel 345, from where it is removed. A stable exit speed for the tube 340 is about between 40 and 60 metres per minute. When using 10 millimetre wide strips of web material 341a to 341 d, it means that the tube 340 is advancing about 10 millimetres per turn or revolution of the mandrel 345. Therefore, as suitable rotational speed for the mandrel 340 is between 4000 revolutions per minute and 6000 revolutions per minute. The strips of web material 341a to 341 d are advancing towards the mandrel at the inner circumference length of the tube per turn or revolution. Therefore, for a 5 millimetre diameter mandrel, the strips 341a to 341 d are advancing towards the mandrel at a speed between 62 metres and 94 metres per minute.

The thickness of the peripheral wall of the tube depends on the thickness of the web material used as well as the number of strips of web material. To produce the peripheral wall thickness of 1.05 millimetres of the outer tube segment 17 of the tubular element 12 of Figure 1A using standard 80 grams per square metre (gsm) uncoated paper having a thickness of about 100 micrometres, about 10 layers or strips of the paper would be required. To produce the peripheral wall thickness of 0.85 millimetres of the inner tube segment 15 of the tubular element 12 of Figure 1 A using the same paper, about 8 or 9 layers or strips of the paper would be required.

The inventors have found that it is possible to use relatively thick web material, that is, a web material having a thickness of about 0.33 millimetres to produce a peripheral wall thickness of 1 millimetre with only 3 layers of web material. The inventors have also found that is possible to use 20 or more layers of web material to produce thicker peripheral walls.

Figure 6 shows a schematic perspective view of another apparatus 400 for forming a tube by spirally winding a plurality of substantially continuous strips of web material. The apparatus 400 of Figure 6 is similar to the apparatus 300 of Figure 5 and operates in the same way but shows further features used in the winding process. The apparatus 400 comprises a mandrel 445 about which a plurality of substantially continuous strips of web material 448 are wound. A drive unit 447 is provided at a first end of the mandrel 445 which rotates the mandrel 445 in a clockwise direction about a longitudinal axis of the mandrel 445 at the desired rotational speed. As the tube 440 is formed by spirally winding the strips of web material 448 around the mandrel 445, the tube is also pulled along the mandrel 445 in the direction of arrow A by an elastic belt 451 wrapped around the external surface of the tube 440 in a figure-8 path and driven endlessly by two vertical drums or rollers 450 on either side of the tube 440.

The apparatus 400 may also comprise smoothing rollers (not shown) placed on either side of the mandrel 445 to apply pressure to the layers of the tube 440 formed from the strips of web material 448 and to smooth any raised edges down. The tube 400 may also enter a dryer or cooler station (not shown) to dry or cure the adhesive bonding the strips of web material 448. Finally, the apparatus 400 comprises a cutter (not shown) that cuts the substantially continuous tube 440 exiting the mandrel 445 into tube segments. The cutter may cut the tube 400 into double-length tube segments or single-length tube segments, as required.

Figure 7 shows a schematic side view of an apparatus 500 for parallel wrapping inner tube segments 503 in a web material 531 to form a substantially continuous outer tube 532 and cutting the outer tube 532 to a predetermined size. The inner tube segments 503 have been produced by a spiral winding process, for example, the apparatus 400 of Figure 6, and have now been passed to the apparatus 500 for Figure 7 for further manufacturing.

In the apparatus 500 of Figure 7, a stream of inner tube segments 503 are fed on to a moving delivery path in the form of a conveyor 507. The longitudinal axes of the inner tube segments 503 are aligned as they are fed onto conveyor 507. The inner tube segments are double-length inner tube segments with each inner tube segment having twice the length L1 of the first tubular portion 14 of the tubular element 12 of Figure 1A, that is, a length of 16 millimetres. There is a predefined space 505 between successive inner tube segments 503. The predefined space is equal to twice the length L2 of the second tubular portion 16 of the tubular element 12 of Figure 1A, that is, a length of 16 millimetres. The conveyor 507 conveys the spaced apart inner tube segments 503 to a performing station or device 509 where the inner tube segments 503 are parallel wrapped in a substantially continuous band of web material 531 that is unwound from a reel or bobbin 511. The band of web material 531 is fed to the performing device 509 such that its lateral sides are parallel to the longitudinal axes of the inner tube segments 503. The stream of spaced apart inner tube segments 503 are placed on top of the band of web material 531. In the performing device 509, the band of web material 531 is parallel wrapped about the longitudinal axes of the inner tube segments 503 such that the lateral sides of the band of web material 531 are brought towards one another, as described in more detail below with respect to Figure 8A. Once the inner tube segments 503 have been parallel wrapped in the band of web material 531 , the wrapped inner tube segments 503 are passed by conveyor 507 to a gluing station or device 513 where glue or adhesive is applied to the lateral sides of the band of web material 531 or a region on one or both of the major surfaces of the band of web material 531 near the lateral sides of the band of web material 531. The lateral sides of the band of web material 531 are then glued together in abutting or overlapping engagement to form a substantially continuous outer tube 532 around the inner tube segments 503, as described in more detail below with respect to Figure 8B.

Following gluing, the substantially continuous outer tube 532 is passed by conveyor 507 to a compressing station or device 515 where the lateral sides of the band of web material 531 are compressed to provide firm engagement between the lateral sides, as described in more detail below with respect to Figure 8C. The substantially continuous outer tube 532 is then passed by conveyor 507 to a drying or cooling station or device 517 to dry or cure the adhesive holding the lateral sides of the band of web material together, as described in more detail below with respect to Figure 8D. Finally, the substantially continuous outer tube 532 comprising the inner tube segments 503 is passed by conveyor 507 to a cutter 519 that cuts the outer tube 532 and inner tube segments to form individual tubular elements 512.

Figure 7A is a schematic side view showing in more detail the spaced apart arrangement between the inner tube segments 503 as they are fed into the apparatus 500 of Figure 7. As discussed above, the inner tube segments 503 are double-length inner tube segments each having a length 2L1 of 16 millimetres, that is, twice the length L1 of the first tubular portion 14 of the tubular element 12 of Figure 1A. Each space 505 between successive inner tube segments 503 is a double space have a length 2L2 of 16 millimetres, that is, twice the length L2 of the second tubular portion 16 of the tubular element 12 of Figure 1A. However, it will be appreciated that different double lengths or spaces could be used depending on the length of the first and second tubular portions of the tubular element. For example, the double space between inner tube segments could be 18 millimetres.

Figures 8A to 8D showing schematic transverse cross-sectional views of the preforming 509, gluing 513, compressing 515 and drying 517 devices respectively used in the apparatus 500 of Figure 7. Referring Figure 8A, the preforming device 509 comprises a flexible guide belt 521 that receives the band of web material 531 and stream of inner tube segments 503 on an upper surface of the guide belt 521. The guide belt 521 extends in a direction parallel to the longitudinal axes of the inner tube segments 503. The preforming device comprises a forming element (not shown) having a generally U-shaped or partial circle groove having a radius of curvature that gradually decreases along the length of the forming element. The guide belt 521 passes longitudinally along the grove in the forming element. The gradually decreasing radius of curvature of the groove causes the guide belt 521 and the band of web material 531 receiving thereon to gradually fold or wrap around the inner tube segment 503 such that the lateral sides 531a and 531b of the band of web material 531 are brought towards one another.

Referring to Figure 8B, the gluing device 513 comprises a glue head 523 that applies glue or adhesive to the lateral sides 531a and 531b of the band of web material 531 or a region on one or both of the major surfaces of the band of web material 531 near the lateral sides 531a and 531 b of the band of web material 531. The lateral sides 531a and 531 b of the band of web material 531 are then glued together in abutting or overlapping engagement to form a substantially continuous outer tube 532 around the inner tube segments 503.

Referring to Figure 8C, the compressing device 515 comprises a compressor 525 that is configured to press the lateral sides 531a and 531b of the band of web material together to provide firm engagement between the lateral sides 531a and 531b.

Referring to Figure 8D, the drying or cooling device 517 comprises a drier to dry or cure the adhesive applied by the gluing device in order to help provide a good bond.

Figure 9 is a schematic side view showing the locations at which the substantially continuous outer tube 532 comprising inner tube segments 503 is cut by the cutter 519 of the apparatus 500 of Figure 7 to form individual tubular elements 512. In the substantially continuous outer tube 532, the inner tube segments 503 are double-length inner tube segments each having a length 2L1 of 16 millimetres. Each space 505 between successive inner tube segments 503 is a double space have a length 2L2 of 16 millimetres or 18 millimetres. The substantially continuous outer tube 532 is cut at locations 534 and 536 denoted by dashed lines in Figure 9. At locations 534, the substantially continuous outer tube 532 and inner tube segments 503 are cut at the mid-point of each double-length inner tube segment 503. At locations 536, the substantially continuous outer tube 532 is cut at the midpoint of each double space 505 between the inner tube segments 503. By cutting at the midpoint of each double length inner tube segment 503 and double space 505, individual tubular elements 512 are produced having first tubular portion 14 with a length L1 of 8 millimetres and a second tubular portion 16 with a length L2 of 8 millimetres or 9 millimetres, as shown in Figure 1A.

Figures 10A to 10E illustrate an apparatus and method for parallel wrapping inner tube segments in a web material and the resulting tubular element. When using a parallel wrapping process such as that used by the apparatus 500 of Figure 7 to make a tubular element such as that shown in Figure 10E, it is desirable to be able to produce a peripheral wall thickness for the outer tube segment of about 0.5 to 1 millimetre so that the second tubular portion of the tubular element has sufficient strength. There are two options for doing this. A first option involves using a single layer of a suitably thick web material. The standard web material used in a parallel wrapping process is 40 gsm paper having a thickness of about 55 micrometres. It is possible to use thicker web materials having a thickness of around 1 millimetre. However, when trying to use thicker web materials, the gluing process becomes more complicated and the compressing stage requires a high pressing force to be applied to the tube, which may jeopardize the ovality or roundness of the final tubular elements. A second option is to use the parallel wrapping process multiple times with each pass through the parallel wrapping process adding another layer of web material until the desired thickness is reached.

Figure 10A shows a schematic view of an apparatus 600 for parallel wrapping a plurality of layers of web material around inner tube segments 603. In particular, the apparatus 600 of Figure 10A is configured to parallel wrap ten layers of 40 gsm wrapping paper around the inner tube segments 603. This type of paper can have a thickness between 0.032 millimetres and 0.055 millimetres. For the purposes of this example, a thickness of 0.05 millimetres is used. The inner tube segments 603 have been made using the above-described spiral winding process and have an internal diameter of 3.3 millimetres and a peripheral wall thickness of 1.4 millimetres to provide an external diameter of 6.1 millimetres. Such an inner tuber segment 603 is illustrated in Figure 10D. The final desired external diameter of the outer tube is 7.1 millimetres. Therefore, a peripheral wall thickness of 0.5 millimetres is required. This can be produced by parallel wrapping ten layers of 40 gsm paper around the inner tube segments 603.

The apparatus 600 of Figure 10A comprises a parallel wrapping apparatus 601 having the preforming 509, gluing 513, compressing 515 and drying 517 devices of the apparatus 500 of Figure 7. As in Figure 7, a stream of spaced apart inner tube segments 603 is firstly fed to the parallel wrapping apparatus 601 and a band of web material (not shown) is parallel wrapped around the spaced apart inner tube segments 603 to form a substantially continuous first outer tube 632.

The apparatus further comprises a rotating knife 661 that cuts the first outer tube 632 to form a plurality of first outer tube subassemblies 640. It should be noted that only one first outer tube subassembly 640 is shown in Figure 10A. In the example of Figure 10A, each first outer tube subassembly 640 comprises a single-length inner tube segment 603a at each end of the first outer tube subassembly 640 and an intermediate section 642 comprising nine double-length inner tube segments 603b arranged between the single-length inner tube segments 603a at each end of the first outer tube subassembly 640. Therefore, each first outer tube subassembly 640 comprises twenty final length tubular elements. The number of double-length inner tube segments 603b in the intermediate section 642 of the first outer tube subassembly 640 can be generally denoted by N. In this example, N equals nine and the apparatus is configured to provide N+1 or ten layers of web material.

Each of the plurality of first outer tube subassemblies 640 is then fed back into the parallel wrapping apparatus 601 as denoted by arrow B in Figure 10A to wrap the plurality of first outer tube subassemblies 640 in a second layer of the web material (not shown) to form a second outer tube (not shown) around the first outer tube subassemblies. The second outer tube and one of the nine double-length inner tube segments of each first outer tube subassembly are cut at the mid-point of the double-length inner tube segment to form a plurality of second outer tube subassemblies (not shown). Each second outer tube subassembly has a similar configuration to the first outer tube subassemblies in that they comprise a single-length inner tube segment at each end of the first outer tube subassembly and nine number double-length inner tube segments between the single-length inner tube segments.

The plurality of second outer tube subassemblies are then fed back to the parallel wrapping apparatus 601 and undergo further wrapping and cutting steps to form further outer tube subassemblies. Each pass through the parallel wrapping apparatus 601 adds an additional layer of web material to the outer tube assemblies. Therefore, by feeding the outer tube subassemblies back through the parallel wrapping apparatus a further eight (N-1) times, an outer tube with ten (N+1) layers of the web material can be produced. Each time an outer tube subassembly is passed through the parallel wrapping apparatus 601 the external diameter of the forming element is adjusted to account for an additional layer of web material being added. Each time an outer tube subassembly is passed through the parallel wrapping apparatus 601 and cut by the rotating knife 661 the outer tube subassembly is cut at the midpoint of an inner tube segment that has not been cut before.

Figure 10B is a schematic cross-sectional side view of the outer tube subassemblies 640 produced by the apparatus of Figure 10A showing the locations of successive cuts (denoted by dotted lines in Figure 10B) with each pass of an outer tube subassembly 640 through the parallel wrapping apparatus 601 . A first cut is made at location 634a to form the first outer tube subassembly. A second cut is made at location 634b to form the second outer tube subassembly. Third and fourth cuts are made at locations 634c and 634d respectively to form third and fourth outer tube subassemblies. Further cuts (not shown) are made until all nine double-length inner tube segments 603b have been cut. In this way, each time an outer tube subassembly is passed through the parallel wrapping apparatus 601 and cut, the outer tube subassembly is cut at the midpoint of an inner tube segment 603b that has not been cut before.

Figure 10C is a schematic cross-sectional side view showing an outer tube subassembly 640 produced by the apparatus of Figure 10A after ten passes through the apparatus 600 of Figure 10A. The peripheral wall thickness T1 of the first tubular portion of each tubular element is now 1.9 millimetres, that is, a thickness of 0.5 millimetres has been added to the 1.4 millimetre thickness of the inner tube segments by adding 10 layers of 40 gsm paper. The peripheral wall thickness T2 of the second tubular portion of each tubular element is now 0.5 millimetres and is defined by the 10 layers of 40 gsm paper. The outer tube subassembly 640 comprises twenty final length tubular elements 612 each having a length Lp of 16 millimetres including the nine double-length inner tube segments 603b in the intermediate portion 642 of the outer tube subassembly 640, which have each been cut in half by the apparatus 600 of Figure 10A. The outer tube subassembly 640 is cut one final time at cut lines 634 and 635 at each end of each tubular element 612 to produce final length tubular elements 612. Such a tubular element 612 is illustrated in Figure 10E.

Figure 11 is flow chart of another method for manufacturing a tubular element for an aerosol-generating article, for example, either the tubular element 12 of Figure 1A or the tubular element 112 of Figure 2A. The method comprises a first step S1 of forming a substantially continuous inner tube from a plurality of layers of a web material using a spiral winding process described above.

In a second step S2, the method comprises cutting the substantially continuous inner tube to form a plurality of inner tube segments. In the case of the tubular element 12 of Figure 1A, the inner tube segments 15 will be cut to the length L1 of the first tubular portion 14 of the tubular element 12. In the case of the tubular element 112 of Figure 2A, the inner tube segments 115 will be cut to the length (L1+L2) of the tubular element 112. It will be appreciated that the inner tube could be cut to form double-length inner tube segments, in which case a further cutting step would be required to cut the inner tube segments to their desired length.

In a third step S3, the method comprises forming a substantially continuous outer tube from a plurality of layers of a web material using a spiral winding process described above. The web material used to form the outer tube could be the same type of material as the web material used to form the inner tube or a different web material could be used, for example, if different properties are required for the outer tube. The outer tube has an internal diameter that is substantially the same as an external diameter of the inner tube.

In a fourth step S4, the method comprises cutting the substantially continuous outer tube to form a plurality of outer tube segments. In the case of the tubular element 12 of Figure 1A, the outer tube segments 17 will be cut to the length L1+L2 of the tubular element 12. In the case of the tubular element 112 of Figure 2A, the outer tube segments 117 will be cut to the length L2 of the second tubular portion 116 of the tubular element 112. It will be appreciated that the outer tube could be cut to form double-length outer tube segments, in which case a further cutting step would be required to cut the outer tube segments to their desired length.

In a fifth step S5, the method comprises inserting the inner tube segments into respective ones of the outer tube segments. Although the outer tube segments have an internal diameter that is substantially the same as an external diameter of the inner tube segments, there is sufficient tolerance in at least one of the diameters to allow for easy insertion, that is, the insertion of an inner tube segment into an outer tube segment does not require excessive force. Preferably, the outer tube segments have an internal diameter that is slightly larger than the external diameter of the inner tube segments or the inner tube segments have an external diameter that is slightly smaller than the internal diameter of the outer tube segments. A suitable tolerance is generally between 0.1 millimetres and 0.3 millimetres.

In a sixth step S6, the method comprises fixing an outer surface of the inner tube segments to an inner surface of its respective outer tube segment. This can be done by applying an adhesive to either the outer surface of the inner tube segment or to an inner surface of the outer tube segment or both prior to the insertion step S5. Fixing the inner and outer tube segments generally comprises curing or drying the adhesive to ensure a secure bond between in the inner and outer tube segments and an tubular element having integral first and second tubular portions.

Figures 12A to 12D illustrate how the steps of the method of Figure 11 can be applied to manufacture a tubular element 712 having first and second tubular portions with different internal diameters. The tubular element 712 comprises an inner tube segment 715 and an outer tube segment 717. The tubular element 712 has the same shape and size as the tubular element 12 of Figure 1A. In particular, the dimensions of the inner tube segment 715 and outer tube segment 717 of tubular element 712 are the same as the inner tube segment 15 and outer tube segment 17 of the tubular element 12 of Figure 1A and are shown on Figure 12A. Furthermore, the arrangement of these components in tubular element 712 is the same as in tubular element 12 of Figure 1A. However, the outer tube segment 717 of the tubular element 712 of Figure 12A is made using a different method to that of tubular element 12 of Figure 1A. The outer tube segment 717 of the tubular element 712 of Figure 12A is made using a spiral winding process rather than by parallel wrapping one or layers of a web material around the inner tube segment 715.

Referring to Figure 12A, this shows the tubular element 712 in a disassembled state, that is, with the inner tube segment 715 separate from the outer tube segment 717. Both the inner tube segment 715 and outer tube segment 717 in the tubular element of Figure 12A have been manufactured using a spiral winding process, for example, using the apparatuses shown in Figures 5 or 6. The inner tube segment 715 is configured to be inserted into the outer tube segment 717 in the direction of arrow C. The external diameter of 5 millimetres of the inner tube segment 15 is substantially the same as the internal diameter of 5 millimetres of the outer tube segment 17 in order to achieve a close fit. However, as discussed above with respect to Figure 11 , it will be appreciated that one or both of these diameters will have sufficient tolerance to allow the inner tube segment 15 to be inserted into the outer tube segment 17 without excessive force. Preferably, the inner tube segment 715 has a smaller external diameter than the internal diameter of the outer tube segment 717. Any resulting gap (not shown) could be occupied, at least partially, by glue or adhesive to provide a fluid buffer during insertion and an air-tight junction between the inner 715 and outer 717 tube segments once the glued is cured.

Figure 12B shows the tubular element 12 of Figure 12A in an assembled state in which the inner tube segment 15 has been inserted into the outer tube segment 17. the arrangement of the inner tube segment 715 and outer tube segment 717 in the tubular element 712 of Figure 12A is the same as the arrangement of these components in tubular element 12 of Figure 1A.

Figure 12C shows a rotating nozzle 772 being used to apply glue or adhesive lines 773 circumferentially around an inner surface of the outer tube segment 717 of the tubular element 712 of Figures 12A and 12B, which is shown in a see-through view. The glue lines 773 are applied prior to insertion of the inner tube segment 715. The glue is EVA glue, although other suitable glues could be used. The glue provides a connection between the inner 715 and outer 717 tube segments both during and after insertion of the inner tube segment 715. It will be appreciated that the glue lines 773 could also be applied circumferentially to an external surface of the inner tube segment 715.

Figure 12D is a see-through view of the tubular element of Figures 12A and 12B in an assembled state. At the righthand side of Figure 12D there is an enlarged view E of the interface between the external surface of the inner tube segment 715 and the outer tube segment 717 in the region surround by circle labelled e in Figure 12D. The enlarged view E shows the adhesive or glue lines 773 between the inner 715 and outer 717 tube segments. The glue lines 773 securely attach the inner 715 and outer 717 tube segments to provide a tubular element 712 having integral first and second tubular portions. The glue lines 773 also help in adjusting the position of the inner 715 and outer 717 tube segments during insertion and create an airtight barrier that prevents leakage between the inner 715 and outer 717 tube segments.

Figure 13 shows an apparatus 800 for assembling the inner 715 and outer 717 tube segments of the tubular element 712 of Figures 12A and 12B. The apparatus 800 comprises a drum 874 which is rotatable about its longitudinal axis. An outer circumferential surface 874a of the drum 874 holds a plurality of inner 715 and outer 717 tube segments, with successive inner 715 and outer 717 tube segments being arranged circumferentially around the drum and parallel to one another. The longitudinal axis of each of the outer tube segments 717 is aligned with the longitudinal axis of a respective one of the inner tube segments 715. Although not shown in Figure 13, the inner tube segments 715 are arranged on a step extending circumferentially around the drum to align the longitudinal axes of the inner 715 and outer 717 tube segments. The outer circumferential surface 874a of the drum 874 is porous. The inner 715 and outer 717 tube segments are held on the outer circumferential surface 874a of the drum 874 by air suction which acts through the porous outer surface in a direction that counteracts the centrifugal force acting on the inner 715 and outer 717 tube segments. However, the inner 715 and outer 717 tube segments are still able to slide longitudinally on the outer circumferential surface 874a of the drum 874.

The apparatus 800 further comprises a fixed rail 875 that remains stationary relative to the rotation of the drum 874. The fixed rail 875 has a camming surface 875a on a side of the rail 875 facing the inner 715 and outer 717 tube segments. The camming surface 875a is tapered and gets wider in the rotational direction of the drum 874. As the drum 874 rotates, the ends of the inner tube segments 715 facing the fixed rail 875 engage the fixed rail 875 and are pushed into the outer tube segments 717 by the camming surface 875a as the drum rotates.

The apparatus 800 may be part of a larger overall manufacturing line for aerosolgenerating article and may be placed between a spiral winding apparatus, for example, those of Figures 5 or 6, and further apparatus for assembling the aerosol-generating article.

It will be appreciated that the steps of the method of Figure 11 can also be applied to manufacture a tubular element having first and second tubular portions with different external diameters. Such a tubular element 912 is shown in Figure 14. The tubular element 912 comprises an inner tube segment 915 and an outer tube segment 917. The tubular element 912 has the same shape and size as the tubular element 112 of Figure 2A. In particular, the dimensions of the inner tube segment 915 and outer tube segment 917 of tubular element 712 are the same as the inner tube segment 115 and outer tube segment 117 of the tubular element 112 of Figure 2A. Although shown back-to-front in Figure 14, it will be appreciated that the arrangement of inner tube segment 915 and outer tube segment 917 in tubular element 912 is the same as these components in tubular element 112 of Figure 2A. Both the inner tube segment 915 and outer tube segment 917 in the tubular element 912 of Figure 14 have been manufactured using a spiral winding process, for example, using the apparatuses shown in Figures 5 or 6.

For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being 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 enumerated herein. In this context, therefore, a number A is understood as A ± 5 percent (5%) of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) 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 enumerated herein.

Claims

1 . An aerosol-generating article comprising: a substrate element comprising an aerosol-generating substrate; and a tubular element comprising integral first and second tubular portions, wherein the first tubular portion and second tubular portion each constitute at least 10 percent of the length of the tubular element; wherein the first tubular portion has a first internal diameter and the second tubular portion has a second internal diameter; wherein the first internal diameter is different to the second internal diameter the second internal diameter being greater than the first internal diameter; wherein the first tubular portion comprises an inner tube segment and a first part of an outer tube segment arranged around the inner tube segment, wherein the second tubular portion comprises a second part of the outer tube segment that extends beyond an end of the inner tube segment in a longitudinal direction of the tubular element, the first internal diameter being the internal diameter of the inner tube segment and the second internal diameter being the internal diameter of the second part of the outer tube segment; and wherein the outer tube segment comprises one or more layers of a web material, the web material being parallel wrapped around the inner tube segment.

2. An aerosol-generating article according to claim 1 , wherein the difference in internal diameter is formed by a step in the internal surface of the tubular element.

3. An aerosol-generating article according to claim 1 or 2, wherein the difference in internal diameter is at least 1 millimetre.

4. An aerosol-generating article according to claim 1 , wherein a ratio of the second internal diameter to the first internal diameter is between 1.2 and 2.5.

5. An aerosol-generating article according to claim 4, wherein a ratio of the second internal diameter to the first internal diameter is between 1.4 and 1.6.

6. An aerosol-generating article according to any preceding claim, wherein the web material of the outer tube segment is a second web material, the inner tube segment comprising a plurality of layers of a first web material.

7. An aerosol-generating article according to claim 6, wherein the inner tube segment comprises a plurality of substantially continuous strips of the first web material, the substantially continuous strips being spirally wound.

8. An aerosol-generating article according to claim 6 or 7, wherein the first web material comprises a cellulosic material.

9. An aerosol-generating article according to any of claims 6 to 8, wherein the second web material comprises a cellulosic material

10. An aerosol-generating article according to claim 8 or 9, wherein the cellulosic material comprises paper or cardboard.

11. An aerosol-generating article according to any of claims 6 to 10, wherein the outer tube segment comprises a plurality of layers of the second web material parallel wrapped around the inner tube segment.

12. An aerosol-generating article comprising: a substrate element comprising an aerosol-generating substrate; and a tubular element comprising integral first and second tubular portions, wherein the first tubular portion and second tubular portion each constitute at least 10 percent of the length of the tubular element; wherein the first tubular portion has a first internal diameter and the second tubular portion has a second internal diameter, the second internal diameter being greater than the first internal diameter; wherein the first tubular portion comprises an inner tube segment and a first part of an outer tube segment arranged around the inner tube segment, wherein the second tubular portion comprises a second part of the outer tube segment that extends beyond an end of the inner tube segment in a longitudinal direction of the tubular element, the first internal diameter being the internal diameter of the inner tube segment and the second internal diameter being the internal diameter of the second part of the outer tube segment; wherein the inner tube segment and the outer tube segment comprise a plurality of spirally wound substantially continuous strips of a web material.

13. An aerosol-generating article according to claim 12, wherein a ratio of the second internal diameter to the first internal diameter is between 1.2 and 2.5.

14. An aerosol-generating article according to claim 12 or 13, wherein the web material comprises a cellulosic material

15. An aerosol-generating article according to claim 14, wherein the cellulosic material comprises paper or cardboard.

16. An aerosol-generating article according to any preceding claim, further comprising a ventilation zone provided at a position along the second tubular portion.

17. An aerosol-generating article according to any preceding claim, wherein the substrate element is arranged upstream of the tubular element and abuts the tubular element.