A method of forming a tubular element for an aerosol-generating article

Abstract

There is provided a method of forming a tubular element (18; 418) for an aerosol-generating article (10; 400), the method comprising providing a tubular body (100) defining a longitudinal axis, wherein the tubular body (100) is formed from one or more of paper, cardboard, acetate tow or polylactic acid (PLA). The method also comprises applying a first folding force to an end (102) of the tubular body (100) to fold the end (102) of the tubular body (100) towards the longitudinal axis to form a flanged tube (106) comprising a first tubular portion (22) defining a cavity (32) extending from a first end (28) of the first tubular portion (22) to a second end (34) of the first tubular portion (22) and further comprising a flanged portion (108) extending from the first end (28) of the first tubular portion (22) towards the longitudinal axis. The method also comprises applying a second folding force to the flanged portion (108) to form a second tubular portion (24) extending parallel to the longitudinal axis and a folded portion (26) extending between the first end (28) of the first tubular portion (22) and the second tubular portion (24). The method also comprises applying a third folding force to the folded portion to position the second tubular portion (24) at least partially inside the cavity (32) defined by the first tubular portion (22).

Description

[0001] A METHOD OF FORMING A TUBULAR ELEMENT FOR AN AEROSOL-GENERATING ARTICLE

[0002] The present invention relates to a method of forming a tubular element for an aerosolgenerating article, the tubular element comprising first and second tubular portions.

[0003] Aerosol-generating articles in which an aerosol-forming substrate, such as a tobaccocontaining 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-forming substrate or material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosolgenerating article, volatile compounds are released from the aerosol-forming 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.

[0004] A number of aerosol-generating devices for consuming heated aerosol-generating articles are known in the art. Such devices include, for example, electrically heated aerosol-generating 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-forming substrate of a heated aerosolgenerating article. For example, electrically heated aerosol-generating devices have been proposed that comprise an internal resistive heater blade which is adapted to be inserted into the aerosol-forming substrate. As an alternative, inductively heatable aerosol-generating articles comprise a susceptor element arranged within the aerosol-forming substrate that can be heated by an alternating magnetic field provided by the aerosol-generating device.

[0005] 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-forming 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 and has a different internal diameter compared to the first tubular plug. For example, the first tubular plug may have a smaller internal diameter to resist or prevent movement of the substrate plug inside the article, for example when an internal resistive heater blade is inserted into the substrate plug.

[0006] 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.

[0007] 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.

[0008] Manufacturing and assembling the first and second tubular plugs of both heated aerosolgenerating 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 concentrically aligned.

[0009] It would be desirable to facilitate easier manufacturing of an aerosol-generating article and reduce the need for accurate positioning and alignment of tubular plugs or elements.

[0010] According to the present disclosure there is provided a method of forming a tubular element for an aerosol-generating article. The method may comprise providing a tubular body defining a longitudinal axis. The method may comprise applying a first folding force to an end of the tubular body to fold the end of the tubular body towards the longitudinal axis to form a flanged tube. The flanged tube may comprise a first tubular portion defining a cavity extending from a first end of the first tubular portion to a second end of the first tubular portion. The flanged tube may comprise a flanged portion extending from the first end of the first tubular portion towards the longitudinal axis. The method may comprise applying a second folding force to the flanged portion to form a second tubular portion extending parallel to the longitudinal axis and a folded portion extending between the first end of the first tubular portion and the second tubular portion. The method may comprise applying a third folding force to the folded portion to position the second tubular portion at least partially inside the cavity defined by the first tubular portion.

[0011] According to an example of the present disclosure there is provided a method of forming a tubular element for an aerosol-generating article, the method comprising providing a tubular body defining a longitudinal axis. The method also comprises applying a first folding force to an end of the tubular body to fold the end of the tubular body towards the longitudinal axis to form a flanged tube comprising a first tubular portion defining a cavity extending from a first end of the first tubular portion to a second end of the first tubular portion and further comprising a flanged portion extending from the first end of the first tubular portion towards the longitudinal axis. The method also comprises applying a second folding force to the flanged portion to form a second tubular portion extending parallel to the longitudinal axis and a folded portion extending between the first end of the first tubular portion and the second tubular portion. The method also comprises applying a third folding force to the folded portion to position the second tubular portion at least partially inside the cavity defined by the first tubular portion.

[0012] The term “aerosol-generating article” is used herein to denote an article in which an aerosol-forming substrate is heated to produce and deliver inhalable aerosol to a consumer. As used herein, the term “aerosol-forming substrate” denotes a substrate from which an aerosol can be formed or generated. The aerosol-forming substrate may be capable of releasing volatile compounds upon heating to generate an aerosol.

[0013] 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 crosssection 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.

[0014] As used herein, the term “length” denotes the dimension of a component for an aerosolgenerating article in the longitudinal direction of the component or the aerosol-generating article. The longitudinal direction of an 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.

[0015] Methods according to examples of the present disclosure form a tubular element comprising a first tubular portion, a second tubular portion, and a folded portion. In other words, the tubular element is a unitary element. The term “unitary element” is used herein to refer to a tubular element that is formed as a single piece or element. In other words, the first tubular portion, the second tubular portion and the folded portion are formed as a single piece or element. This is in contrast to arrangements in known aerosol-generating articles that have separate tubular elements corresponding to the first and second tubular portions of tubular elements formed according to the methods described herein and which have to be assembled together during manufacture of the aerosol-generating article. Advantageously, the methods according to examples of the present disclosure facilitate formation of the tubular element as a unitary element by forming the tubular element from a single tubular body.

[0016] By forming the tubular element as a unitary element, the tubular element is advantageously formed as a single piece. Advantageously, this simplifies the manufacture of the tubular element and eliminates any difficulties in positioning the first and second tubular portions relative to each other compared to forming the first and second tubular portions as separate elements. For example, there is no need to accurately bring the first and second tubular portions into abutting engagement because the unitary tubular element automatically achieves the advantages of this configuration. The unitary nature of the tubular element also ensures that the first and second tubular portions are axially aligned. Advantageously, this ensures a smooth airflow through the tubular element and helps to provide a consistent consumer experience.

[0017] Preferably, the step of applying the first folding force comprises contacting the end of the tubular body with a flanging mandrel. Advantageously, using a flanging mandrel to apply the first folding force may facilitate uniform folding of the end of the tubular body.

[0018] Preferably, the flanging mandrel has a concave end face and the step of contacting the end of the tubular body with the flanging mandrel comprise contacting the end of the tubular body with the concave end face of the flanging mandrel.

[0019] Preferably, the flanging mandrel is rotated during the step of contacting the end of the tubular body with the flanging mandrel. Advantageously, rotating the flanging mandrel during the contacting step may further facilitate uniform folding of the end of the tubular body. The flanging mandrel may have a generally cylindrical shape comprising a first end and a second end, wherein the flanging mandrel is rotated about a longitudinal axis extending between the first end and the second end. In examples in which the flanging mandrel has a concave end face, preferably the concave end face is positioned at the first end or the second end of the flanging mandrel.

[0020] The flanging mandrel may be formed from any suitable material. Preferably, the flanging mandrel is formed from a metal or a metal alloy. For example, the flanging mandrel may comprise aluminium, stainless steel, or titanium.

[0021] The steps of applying the second folding force and applying the third folding force may be performed concurrently. The second folding force and the third folding force may be a single folding force. The single folding force may also be referred to as a combined folding force. Advantageously, concurrently applying the second folding force and the third folding force may simplify the method of forming the tubular element.

[0022] The steps of applying the second folding force and applying the third folding force may comprise compressing the flanged portion between a first mandrel and a second mandrel. Advantageously, applying the second folding force and applying the third folding force by compressing the flanged portion between a first mandrel and a second mandrel may facilitate consistent and repeatable formation of the tubular element so that multiple identical tubular elements can be formed reliably.

[0023] Preferably, the first mandrel is an inner mandrel and the second mandrel is an outer mandrel, wherein the step of compressing the flanged portion comprises inserting the inner mandrel and the flanged portion into the outer mandrel. Preferably, the inner mandrel is positioned inside the first tubular portion during the step of inserting the inner mandrel and the flanged portion into the outer mandrel.

[0024] The inner mandrel may comprise an inner mandrel forming surface comprising a first cylindrical outer surface, a second cylindrical outer surface, and a recessed chamfered outer surface extending between the first cylindrical outer surface and the second cylindrical outer surface. The outer mandrel may comprise a recess defining an outer mandrel forming surface comprising a first cylindrical inner surface, a second cylindrical inner surface, and a frustoconical inner surface extending between the first cylindrical inner surface and the second cylindrical inner surface.

[0025] Preferably, the shape of the inner mandrel forming surface defines an internal shape of the tubular element. Preferably, the shape of the outer mandrel forming surface defines an external shape of the tubular element.

[0026] Preferably, the shape of the inner mandrel forming surface is complementary with the shape of the outer mandrel forming surface.

[0027] Preferably, the step of inserting the inner mandrel and the flanged portion into the outer mandrel compresses the flanged portion between the inner mandrel forming surface and the outer mandrel forming surface. Advantageously, compressing the flanged portion between the inner mandrel forming surface and the outer mandrel forming surface applies the second folding force and the third folding force to the flanged portion.

[0028] Preferably, at least one of the first mandrel and the second mandrel is rotated during the step of compressing the flanged portion. Advantageously, rotating at least one of the first mandrel and the second mandrel during the step of compressing the flanged portion may facilitate uniform folding of the flanged portion.

[0029] The first mandrel may have a generally cylindrical shape comprising a first end and a second end, wherein the first mandrel is rotated about a longitudinal axis extending between the first end and the second end.

[0030] The second mandrel may have a generally cylindrical shape comprising a first end and a second end, wherein the second mandrel is rotated about a longitudinal axis extending between the first end and the second end.

[0031] Each of the first mandrel and the second mandrel may be formed from any suitable material. Preferably, the first mandrel and the second mandrel are formed from the same material. Preferably, each of the first mandrel and the second mandrel is formed from a metal or a metal alloy. For example, each of the first mandrel and the second mandrel may comprise aluminium, stainless steel, or titanium.

[0032] The steps of applying the first folding force and applying the second folding force may be performed concurrently. The steps of applying the first folding force, applying the second folding force, and applying the third folding force may be performed concurrently. Advantageously, concurrently applying the folding forces may simplify the method of forming the tubular element.

[0033] The steps of applying the first folding force and applying the second folding force may comprise compressing the end of the tubular body between a first mandrel and at least one second mandrel. Advantageously, applying the first folding force and applying the second folding force by compressing the flanged portion between a first mandrel and at least one second mandrel may facilitate consistent and repeatable formation of the tubular element so that multiple identical tubular elements can be formed reliably.

[0034] Preferably, the first mandrel is an inner mandrel and the at least one second mandrel comprises a plurality of outer mandrels, wherein the step of compressing the end of the tubular body between the first mandrel and the at least one second mandrel comprises compressing the end of the tubular body between the inner mandrel and the plurality of outer mandrels.

[0035] Preferably, the inner mandrel is positioned inside the tubular body during the step of compressing the end of the tubular body between the inner mandrel and the plurality of outer mandrels.

[0036] The inner mandrel may have a cylindrical shape and a cylindrical outer surface, wherein the cylindrical outer surface forms an inner mandrel forming surface. Each outer mandrel may comprise a concave inner surface forming an outer mandrel forming surface. Preferably, the step of compressing the end of the tubular body between the inner mandrel and the plurality of outer mandrels comprises compressing the end of the tubular body between the inner mandrel forming surface and the plurality of outer mandrel forming surfaces.

[0037] Preferably, the cylindrical outer surface of the inner mandrel has a first radius of curvature and the concave inner surface of each outer mandrel has a second radius of curvature, wherein the first radius of curvature is the same as the second radius of curvature.

[0038] Preferably, the step of applying the third folding force comprises moving each of the at least one second mandrels parallel to the longitudinal axis of the tubular body.

[0039] Each of the first mandrel and the second mandrels may be formed from any suitable material. Preferably, the first mandrel and the second mandrels are formed from the same material. Preferably, each of the first mandrel and the second mandrels is formed from a metal or a metal alloy. For example, each of the first mandrel and the second mandrels may comprise aluminium, stainless steel, or titanium.

[0040] The method may comprise securing the tubular body within a tube holder during the steps of applying the first folding force, applying the second folding force, and applying the third folding force. The tube holder may have a cylindrical shape. The tube holder may comprise a central bore, wherein the step of securing the tubular body within the tube holder comprises positioning part of the tubular body within the central bore. Preferably, the tubular body is received within the central bore with an interference fit.

[0041] The tubular body may comprise a first end and a second end opposite the first end. The method may comprise applying each of the first folding force, the second folding force and the third folding force to both the first end and the second end. Advantageously, applying the folding forces to both ends of the tubular body may form a double-ended tubular element.

[0042] Preferably, the method comprises cutting the double-ended tubular element to form two tubular elements. Advantageously, applying the folding forces to both ends of the tubular body and cutting the double-ended tubular element to form two tubular elements facilitates the formation of two tubular elements from a single tubular body. Preferably, the folding forces are applied concurrently to the first end and the second end of the tubular element.

[0043] Advantageously, forming two tubular elements from a single tubular body may increase the production speed of the tubular elements. Preferably, the step of cutting the double-ended tubular element comprises cutting the double-ended tubular element at a midpoint along a length of the double-ended tubular element.

[0044] The second tubular portion may have a first end and a second end, wherein the folded portion extends between the first end of the first tubular portion and the second end of the second tubular portion. Preferably, the step of applying a third folding force positions the second end of the second tubular portion inside the cavity defined by the first tubular portion. Advantageously, this arrangement may result in a tubular element in which the first tubular portion has a larger internal diameter than the second tubular portion. This may be particularly advantageous when the tubular element forms part of an aerosol-generating article in which the second tubular portion abuts a substrate element comprising an aerosol-forming substrate. For example, the smaller diameter of the second tubular portion may resist or prevent movement of the substrate element within the aerosol-generating article, for example when an internal resistive heater blade is inserted into the substrate element.

[0045] In some examples, the tubular element may comprise an upstream end and a downstream end, wherein the first end of each of the first tubular portion and the second tubular portion is positioned closer to the upstream end than the downstream end, and wherein the second end of each of the first tubular portion and the second tubular portion is positioned closer to the downstream end than the upstream end. The first end of the first tubular portion may be an upstream end of the first tubular portion and a second end of the first tubular portion may be a downstream end of the of the first tubular portion. The first end of the second tubular portion may be an upstream end of the second tubular portion and the second end of the second tubular portion may be a downstream end of the second tubular portion.

[0046] In some examples, the folded portion extends between the upstream end of the first tubular portion and the downstream end of the second tubular portion, and the downstream end of the second tubular portion is positioned inside the cavity. Advantageously, in this arrangement the folded portion may resist or prevent movement of the second tubular portion further into the cavity. Furthermore, in this arrangement, the folded portion may define an annular recess extending between the upstream end of the first tubular portion and the downstream end of the second tubular portion. The annular recess may be particularly advantageous in embodiments in which the tubular element forms part of an aerosol-generating article including a substrate element comprising a capsule containing the aerosol-forming substrate and the aerosol-forming substrate comprises a powder, since the annular recess may collect the powder and reduce the likelihood of the powder leaking out of the aerosol-generating article once the capsule has been pierced.

[0047] The third folding force may be removed while the first end of the second tubular portion remains outside the cavity defined by the first tubular portion. The third folding force may be removed when the first end of the second tubular portion is flush with the first end of the first tubular portion. The third folding force may be applied until the second tubular portion is positioned entirely inside the cavity defined by the first tubular portion.

[0048] Preferably, the third folding force is applied until an angle between the folded portion and an inner surface of the first tubular portion is less than 90 degrees. For example, the angle between the folded portion and the inner surface of the first tubular portion may be less than 85 degrees, less than 80 degrees, less than 75 degrees, less than 70 degrees, less than 65 degrees, less than 60 degrees, less than 55 degrees, less than 50 degrees, or less than 45 degrees.

[0049] Preferably, the third folding force is applied until an angle between the folded portion and an outer surface of the second tubular portion is less than 90 degrees. For example, the angle between the folded portion and the outer surface of the second tubular portion may be less than 85 degrees, less than 80 degrees, less than 75 degrees, less than 70 degrees, less than 65 degrees, less than 60 degrees, less than 55 degrees, less than 50 degrees, or less than 45 degrees.

[0050] Preferably, the angle between the folded portion and the inner surface of the first tubular portion is the same as the angle between the folded portion and the outer surface of the second tubular portion. Advantageously, this arrangement may provide a folded portion having a substantially linear cross-sectional profile and coaxial alignment of the second tubular portion with the first tubular portion.

[0051] The first tubular portion may have a first internal diameter and the second tubular portion may have a second internal diameter. The first internal diameter may be uniform or constant along the length of the first tubular portion. The second internal diameter may be uniform or constant along the length of the second tubular portion.

[0052] The second internal diameter may be smaller than the first internal diameter. The difference between the first internal diameter and the second internal diameter may be at least 1 millimetre, at least 2 millimetres, at least 3 millimetres, at least 4 millimetres, at least 5 millimetres, or at least 6 millimetres.

[0053] The first internal diameter may be at least 4 millimetres, at least 4.5 millimetres, at least 5 millimetres, at least 5.5 millimetres, at least 6 millimetres, at least 6.5 millimetres, at least 7 millimetres, at least 7.5 millimetres, at least 8 millimetres, or at least 8.5 millimetres. The first internal diameter may be less than 9 millimetres, less than 8.5 millimetres, less than 8 millimetres, less than 7.5 millimetres, less than 7 millimetres, less than 6.5 millimetres, less than 6 millimetres, less than 5.5 millimetres, less than 5 millimetres, or less than 4.5 millimetres. The first internal diameter may be between 4 millimetres and 9 millimetres, between 5 millimetres and 8.5 millimetres, between 6 millimetres and 8.5 millimetres, between 6.5 millimetres and 8 millimetres, or between 6.5 millimetres and 7.5 millimetres.

[0054] The second internal diameter may be at least 1 millimetre, at least 1.25 millimetres, at least

[0055] 1.5 millimetres, at least 1.75 millimetres, at least 2 millimetres, at least 2.25 millimetres, at least

[0056] 2.5 millimetres, at least 2.75 millimetres, at least 3 millimetres, at least 3.25 millimetres, at least

[0057] 3.5 millimetres, or at least 3.75 millimetres. The second internal diameter may be less than 4 millimetres, less than 3.75 millimetres, less than 3.5 millimetres, less than 3.25 millimetres, less than 3 millimetres, less than 2.75 millimetres, less than 2.5 millimetres, less than 2.25 millimetres, less than 2 millimetres, less than 1.75 millimetres, less than 1.5 millimetres, or less than 1.25 millimetres. The second internal diameter may be between 1 millimetre and 4 millimetres, between 2 millimetres and 3 millimetres, or between 2.25 millimetres and 2.75 millimetres.

[0058] The first tubular portion may have a first length and the second tubular portion may have a second length. The second length may be smaller than the first length.

[0059] Advantageously, providing a second tubular portion that is shorter than the first tubular portion may reduce the material required to form the tubular element. This may be particularly advantageous in examples in which second tubular portion has a smaller internal diameter than the first tubular portion and is provided only to resist or prevent movement of the substrate element within the aerosol-generating article.

[0060] The second length may less than 50 percent of the first length, less than 45 percent of the first length, less than 40 percent of the first length, less than 35 percent of the first length, less than 30 percent of the first length, less than 25 percent of the first length, less than 20 percent of the first length, less than 15 percent of the first length, or less than 10 percent of the first length.

[0061] The first length may be at least 10 millimetres, at least 13 millimetres, at least 15 millimetres, at least 20 millimetres, at least 25 millimetres, at least 30 millimetres, or at least 35 millimetres. The first length may be less than 40 millimetres, less than 35 millimetres, less than 30 millimetres, less than 25 millimetres, less than 20 millimetres, less than 15 millimetres, or less than 13 millimetres. The first length may be between 10 millimetres and 40 millimetres, between 10 millimetres and 30 millimetres, or between 10 millimetres and 20 millimetres. The first length may be between 13 millimetres and 30 millimetres, between 16 millimetres and 27 millimetres, or between 18 millimetres and 23 millimetres.

[0062] The first tubular portion may have a first external diameter and the second tubular portion may have a second external diameter. The first external diameter may be uniform or constant along the length of the first tubular portion. The second external diameter may be uniform or constant along the length of the second tubular portion.

[0063] The second external diameter may be smaller than the first external diameter. The difference between the first external diameter and the second external diameter may be at least 1 millimetre, at least 2 millimetres, at least 3 millimetres, at least 4 millimetres, at least 5 millimetres, or at least 6 millimetres.

[0064] The first external diameter may be at least 4 millimetres, at least 4.5 millimetres, at least 5 millimetres, at least 5.5 millimetres, at least 6 millimetres, at least 6.5 millimetres, at least 7 millimetres, at least 7.5 millimetres, at least 8 millimetres, or at least 8.5 millimetres. The first external diameter may be less than 9 millimetres, less than 8.5 millimetres, less than 8 millimetres, less than 7.5 millimetres, less than 7 millimetres, less than 6.5 millimetres, less than 6 millimetres, less than 5.5 millimetres, less than 5 millimetres, or less than 4.5 millimetres. The first external diameter may be between 4 millimetres and 9 millimetres, between 5 millimetres and 8.5 millimetres, between 6 millimetres and 8.5 millimetres, between 6.5 millimetres and 8 millimetres, or between 6.5 millimetres and 7.5 millimetres.

[0065] The second external diameter may be at least 1 millimetre, at least 1.25 millimetres, at least

[0066] 1.5 millimetres, at least 1.75 millimetres, at least 2 millimetres, at least 2.25 millimetres, at least

[0067] 2.5 millimetres, at least 2.75 millimetres, at least 3 millimetres, at least 3.25 millimetres, at least

[0068] 3.5 millimetres, or at least 3.75 millimetres. The second external diameter may be less than 4 millimetres, less than 3.75 millimetres, less than 3.5 millimetres, less than 3.25 millimetres, less than 3 millimetres, less than 2.75 millimetres, less than 2.5 millimetres, less than 2.25 millimetres, less than 2 millimetres, less than 1.75 millimetres, less than 1.5 millimetres, or less than 1.25 millimetres. The second external diameter may be between 1 millimetre and 4 millimetres, between 2 millimetres and 3 millimetres, or between 2.25 millimetres and 2.75 millimetres.

[0069] In examples in which the downstream end of the second tubular portion is positioned inside the cavity, a distance in the longitudinal direction between the upstream end of the first tubular portion and the downstream end of the second tubular portion may be referred to as a length of overlap. The length of overlap may be at least 0.5 millimetres, at least 0.75 millimetres, at least 1 millimetre, at least 1.25 millimetres, at least 1.5 millimetres, at least 1.75 millimetres, at least 2 millimetres, at least 2.25 millimetres, at least 2.5 millimetres, or at least 2.75 millimetres. The length of overlap may be less than 3 millimetres, less than 2.75 millimetres, less than 2.5 millimetres, less than 2.25 millimetres, less than 2 millimetres, less than 1.75 millimetres, less than 1.5 millimetres, less than 1.25 millimetres, less than 1 millimetre, or less than 0.75 millimetres. The length of overlap may be between 0.5 millimetres to 3 millimetres, between 0.75 millimetres and 1.5 millimetres, or between 0.9 millimetres and 1.1 millimetres.

[0070] The tubular element may have a length of at least 10 millimetres, at least 13 millimetres, at least 15 millimetres, at least 20 millimetres, at least 25 millimetres, at least 30 millimetres, or at least 35 millimetres. The length of the tubular element may be less than 40 millimetres, less than 35 millimetres, less than 30 millimetres, less than 25 millimetres, less than 20 millimetres, less than 15 millimetres, or less than 13 millimetres. The length of the tubular element may be between 10 millimetres and 40 millimetres, between 10 millimetres and 30 millimetres, or between 10 millimetres and 20 millimetres. The length of the tubular element may be between 13 millimetres and 30 millimetres, between 16 millimetres and 27 millimetres, or between 18 millimetres and 23 millimetres.

[0071] The tubular element may comprise at least one airflow aperture extending through the folded portion. Advantageously, the at least one airflow aperture may provide at least one additional route for air to flow into the cavity. In particular, airflow may enter the cavity through the second tubular portion and through the at least one airflow aperture.

[0072] The method may comprise a step of forming the at least one airflow aperture through the tubular body before the steps of applying the first, second and third folding forces. Alternatively, the method may comprise a step of forming the at least one airflow aperture through the folded portion after the first, second and third folding forces have been applied.

[0073] The at least one airflow aperture may be formed using any suitable process. For example, the at least one airflow aperture may be formed using laser perforation.

[0074] The at least one airflow aperture may comprise a plurality of airflow apertures. The plurality of airflow apertures may comprise two, three, four, five, six, seven, eight, nine, or ten airflow apertures. Preferably, the airflow apertures are arranged symmetrically around the folded portion.

[0075] The tubular body may be formed from any suitable material. The tubular body may be formed from one or more of paper, cardboard, acetate tow or polylactic acid (PLA). In preferred examples, the tubular body is formed from at least one of paper and cardboard. Advantageously, forming the tubular body from at least one of paper and cardboard may provide one or more environmental and sustainability advantages compared to tubular segments formed from polymeric materials such as acetate.

[0076] The tubular body may be formed from a material having a grammage of between 100 grams per square metre and 700 grams per square metre, preferably between 100 grams per square metre and 400 grams per square metre.

[0077] The method according to the present disclosure may be used to form multiple tubular elements. In examples in which the method is used to form multiple tubular elements, the step of providing the tubular body may comprise providing a plurality of tubular bodies. The step of providing a plurality of tubular bodies may comprise feeding the plurality of tubular bodies into the hopper. The step of providing the plurality of tubular bodies may also comprise feeding each tubular body from the hopper into an alignment drum. Advantageously, the alignment drum may position each tubular body in the correct orientation required for the step of applying the first folding force. Preferably, the alignment drum comprising a plurality of grooves positioned around a periphery of the drum, wherein each groove may receive one of the tubular bodies from the hopper. In examples in which the first folding force is applied with a flanging mandrel, an end of each tubular body may be contacted with the flanging mandrel while the tubular body is positioned in a groove of the alignment drum. Alternatively, each tubular body may be transferred from the alignment drum to a flanging unit comprising the flanging mandrel.

[0078] According to the present disclosure, there is further providing a method of forming an aerosol-generating article. The method comprising providing a plurality of elements comprising a substrate element comprising an aerosol-forming substrate and a tubular element formed according to the method described herein. The method of forming an aerosol-generating article also comprises assembling the plurality of elements together in the form of a rod to form an aerosol-generating article.

[0079] The method of forming the tubular element and the method of forming the aerosolgenerating article may be carried out in a single process. In other words, the tubular element may be formed according to the method described herein immediately before being combined with the substrate element to form the aerosol-generating article. Alternatively, the tubular element may be formed according to the method described herein and subsequently transferred to a separate production line for combination with the substrate element.

[0080] The assembling step may comprise positioning the tubular element adjacent to the substrate element. Preferably, the tubular element abuts the substrate element. Preferably, the second tubular portion abuts the substrate element.

[0081] The plurality of elements may comprise a mouthpiece element. The assembling step may comprise positioning the tubular element between the substrate element and the mouthpiece element.

[0082] The mouthpiece element may be positioned at a downstream end of the aerosol-generating article. Preferably, the mouthpiece element is positioned immediately downstream of the tubular element.

[0083] An upstream end of the substrate element may define an upstream end of the aerosolgenerating article. An upstream end of the tubular element may be adjacent a downstream end of the substrate element. An upstream end of the mouthpiece element may be adjacent a downstream end of the tubular element. A downstream end of the mouthpiece element may define a downstream end of the aerosol-generating article.

[0084] The mouthpiece element may comprise at least one mouthpiece filter segment of a fibrous filtration material for filtering the aerosol that is generated from the aerosol-forming substrate. Suitable fibrous filtration materials are 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.

[0085] Preferably, the mouthpiece element has a low particulate filtration efficiency.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] The aerosol-generating article may comprise a ventilation zone at a location along the tubular element. Preferably, the ventilation zone is provided at a location along the first tubular portion.

[0092] Advantageously, the ventilation zone may provide a desired cooling of a stream of aerosol generated upon heating of the aerosol-forming substrate and drawn through the tubular element.

[0093] The ventilation zone may comprise a plurality of ventilation holes or perforations through a peripheral wall of the first 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.

[0094] The aerosol-generating article may have a ventilation level of at least about 5 percent.

[0095] The term “ventilation level” is used herein to denote a volume ratio of the airflow admitted into the aerosol-generating article via the ventilation zone (ventilation airflow) to 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.

[0096] 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 aerosol- generating 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 30 percent.

[0097] Preferably, the substrate element is positioned immediately upstream of the tubular element. Preferably, the substrate element abuts an upstream end of the tubular element.

[0098] Preferably, the substrate element is circumscribed by a plug wrap.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] The aerosol-forming substrate may be a solid aerosol-forming substrate. The aerosolforming substrate may be a rod of aerosol-forming substrate.

[0103] The aerosol-forming substrate preferably comprises an aerosol former.

[0104] 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 facilitate resistance of the aerosol 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.

[0105] 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.

[0106] The aerosol-forming 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-forming substrate.

[0107] The aerosol-forming 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-forming substrate.

[0108] The aerosol-forming 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-forming substrate.

[0109] The aerosol-forming 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 aerosol-forming substrate.

[0110] The aerosol-forming 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 aerosol-forming substrate.

[0111] The aerosol-forming substrate may comprise tobacco.

[0112] The aerosol-forming substrate may comprise a plurality of shreds of tobacco material. The aerosol-forming substrate may comprise a plurality of shreds of homogenised tobacco material.

[0113] As used herein with reference to the invention, the term “shred” denotes an element having a length substantially greater than a width and a thickness thereof.

[0114] As used herein with reference to the invention, the term “homogenised tobacco material” is used to describe material formed by agglomerating particulate tobacco material.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] The shreds of tobacco material may have a length of at least about 10 millimetres.

[0122] The shreds of tobacco material may have a length of less than or equal to about 40 millimetres.

[0123] 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 substrate element. 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 substrate element.

[0124] 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 substrate element. 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 substrate element.

[0125] 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 substrate element. 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 substrate element.

[0126] The size of the components of the aerosol-forming substrate, such as a plurality of shreds of tobacco material, may play a role in the distribution of heat inside the aerosol-forming substrate. Also, the size of the components of the aerosol-forming substrate may play a role in the RTD of the article.

[0127] The aerosol-forming substrate may comprise a plurality of pellets or granules of tobacco material. The aerosol-forming substrate may comprise a plurality of pellets or granules of homogenised tobacco material.

[0128] The aerosol-forming substrate may comprise one or more sheets of tobacco material.

[0129] The aerosol-forming substrate may comprise one or more sheets of homogenised tobacco material.

[0130] 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.

[0131] As used herein with reference to the invention, 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-forming substrate. For example, if the aerosol-forming 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-forming substrate.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] The one or more sheets of tobacco material may each individually have a length substantially the same as the length of the aerosol-forming substrate.

[0136] The one or more sheets of tobacco material may have been one or more of crimped, folded, gathered, and pleated.

[0137] 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.

[0138] The substrate element may comprise a capsule, wherein the aerosol-forming substrate is contained within the capsule.

[0139] The capsule may comprise a first frangible portion at an upstream end of the capsule and a second frangible portion at a downstream end of the capsule. Advantageously, the first and second frangible portions may facilitate piercing of the capsule prior to use of the aerosolgenerating article.

[0140] 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.

[0141] 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.

[0142] The capsule may comprise one or more nicotine salts.

[0143] 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.

[0144] The pharmaceutically active particles may have a mass median aerodynamic diameter of at least about 0.5 micrometres, or at least about 1 micrometre.

[0145] The pharmaceutically active particles may have a mass median aerodynamic diameter of between about 0.5 micrometres and about 4 micrometres.

[0146] 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”.

[0147] 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.

[0148] The capsule may hold or contain at least about 5 milligrams of nicotine particles, or at least about 10 milligrams of nicotine particles.

[0149] 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.

[0150] The capsule may contain flavour particles.

[0151] The substrate element may comprise a susceptor element. Preferably, the susceptor element is arranged within the aerosol-forming substrate.

[0152] The term “susceptor” is used herein to refer 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.

[0153] Preferably, the susceptor element is arranged in thermal contact with the aerosol-forming substrate. Therefore, when the susceptor element heats up, the aerosol-forming substrate is heated by the susceptor element to generate an aerosol. The susceptor element may be arranged in direct physical contact with the aerosol-forming substrate.

[0154] The susceptor element may be an elongate susceptor element.

[0155] The term “elongate” is used herein to describe a component of the aerosol-generating article having a length greater than a width and a thickness of the component.

[0156] The elongate susceptor element may be arranged substantially longitudinally within the aerosol-forming substrate. In other words, the longitudinal axis of the elongate susceptor element may be approximately parallel to the longitudinal axis of the substrate element. For example, the longitudinal axis of the elongate susceptor element may be within plus or minus 10 degrees of parallel to the longitudinal axis of the substrate element. The elongate susceptor element may be located in a radially central position within the aerosol-forming substrate, and extend along the longitudinal axis of the substrate element.

[0157] The susceptor element may extend from a downstream end of the aerosol-forming substrate towards an upstream end of the aerosol-forming substrate.

[0158] The susceptor element may extend from the upstream end of the aerosol-forming substrate towards the downstream end of the aerosol-forming substrate.

[0159] The susceptor element may extend from the upstream end of the aerosol-forming substrate to the downstream end of the aerosol-forming substrate. In other words, the susceptor element may extend along the entire length of the aerosol-forming substrate.

[0160] The length of the susceptor element may be substantially the same as the length of the substrate element.

[0161] The susceptor element may extend part way along the length of the substrate element.

[0162] The susceptor element may be spaced apart from the downstream end of the substrate element.

[0163] The susceptor element may be spaced apart from the upstream end of the substrate element.

[0164] The susceptor element may be spaced apart from both a downstream end and an upstream end of the substrate element.

[0165] The length of the susceptor element may be less than the length of the substrate element.

[0166] The susceptor element may be entirely enclosed within the aerosol-forming substrate. In other words, the aerosol-forming substrate may completely surround the susceptor element.

[0167] The susceptor element may be in the form of a pin, rod, strip or blade.

[0168] The susceptor element may have a length of at least about 5 millimetres, at least about 6 millimetres, or at least about 8 millimetres. The susceptor element 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.

[0169] 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.

[0170] The susceptor element 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.

[0171] The susceptor element 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.

[0172] The susceptor element may have a width of at least about 1 millimetre.

[0173] The susceptor element may have width of less than or equal to about 5 millimetres.

[0174] The susceptor element may have a width of between about 1 millimetre and about 5 millimetres.

[0175] The susceptor element may have a thickness of at least about 0.01 millimetres, or at least about 0.5 millimetres.

[0176] The susceptor element 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.

[0177] The susceptor element 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 element may have a thickness of between about 0.5 millimetres and about 2 millimetres.

[0178] The susceptor element may have a substantially circular cross-section.

[0179] The susceptor element may have a substantially constant cross-section along the length of the susceptor element.

[0180] If the susceptor element 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 element in the form of a strip of blade may have a width of about 4 millimetres.

[0181] If the susceptor element 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 element in the form of a strip of blade may have a thickness of about 0.07 millimetres, or about 0.06 millimetres.

[0182] The susceptor element 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 element may comprise a metal or carbon.

[0183] The susceptor element 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 element 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.

[0184] Therefore, parameters of the susceptor element 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 element may be heated to a temperature in excess of 250 degrees Celsius during use.

[0185] Suitable susceptors elements 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 element may have a protective external layer, for example a protective ceramic layer or protective glass layer encapsulating the susceptor material. The susceptor element may comprise a protective coating formed by a glass, a ceramic, or an inert metal, formed over a core of susceptor material.

[0186] The susceptor element may be a multi-material susceptor element and may comprise a first susceptor material and a second susceptor material.

[0187] The aerosol-generating article may 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 element.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] The assembling step may comprise wrapping at least one wrapper around the plurality of elements.

[0192] The aerosol-generating article may comprise a wrapper circumscribing at least one component of the aerosol-generating article. The wrapper may circumscribe the tubular element and at least one additional 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. The wrapper may circumscribe all components of the aerosol-generating 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.

[0193] The wrapper may be an outer wrapper. The wrapper may be the outermost wrapper. The outer surface of the wrapper may form at least part of the outer surface of the aerosol-generating article. The wrapper may be porous or be provided with ventilation means.

[0194] Preferably, the wrapper is formed from paper. The wrapper may have a grammage of at least 20 grams per square metre, at least 40 grams per square metre, at least 60 grams per square metre, at least 80 grams per square metre, at least 100 grams per square metre, at least 120 grams per square metre, at least 140 grams per square metre, at least 160 grams per square metre, or at least 180 grams per square metre. The wrapper may have a grammage of less than 200 grams per square metre, less than 180 grams per square metre, less than 160 grams per square metre, less than 140 grams per square metre, less than 120 grams per square metre, less than 100 grams per square metre, less than 80 grams per square metre, less than 60 grams per square metre, or less than 40 grams per square metre. The wrapper may have a grammage of between 20 grams per square metre and 200 grams per square metre, or between 50 grams per square metre and 100 grams per square metre.

[0195] 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.

[0196] Example 1 : A method of forming a tubular element for an aerosol-generating article, the method comprising: providing a tubular body defining a longitudinal axis; applying a first folding force to an end of the tubular body to fold the end of the tubular body towards the longitudinal axis to form a flanged tube comprising a first tubular portion defining a cavity extending from a first end of the first tubular portion to a second end of the first tubular portion and further comprising a flanged portion extending from the first end of the first tubular portion towards the longitudinal axis; applying a second folding force to the flanged portion to form a second tubular portion extending parallel to the longitudinal axis and a folded portion extending between the first end of the first tubular portion and the second tubular portion; and applying a third folding force to the folded portion to position the second tubular portion at least partially inside the cavity defined by the first tubular portion.

[0197] Example 2: A method according to Example 1 , wherein the steps of applying the second folding force and applying the third folding force are performed concurrently so that the second folding force and the third folding force are a single folding force.

[0198] Example 3: A method according to Example 1 or 2, wherein the step of applying the first folding force comprise contacting the end of the tubular body with a flanging mandrel.

[0199] Example 4: A method according to Example 3, wherein the step of contacting the end of the tubular body with the flanging mandrel comprises contacting the end of the tubular body with a concave end face of the flanging mandrel.

[0200] Example 5: A method according to Example 3 or 4, wherein the flanging mandrel is rotated during the step of contacting the end of the tubular body with the flanging mandrel.

[0201] Example 6: A method according to any preceding Example, wherein the steps of applying the second folding force and applying the third folding force comprise compressing the flanged portion between a first mandrel and a second mandrel.

[0202] Example 7: A method according to Example 6, wherein the first mandrel is an inner mandrel and the second mandrel is an outer mandrel, and wherein the step of compressing the flanged portion comprises inserting the inner mandrel and the flanged portion into the outer mandrel. Example 8: A method according to Example 7, wherein the inner mandrel is positioned inside the first tubular portion during the step of inserting the inner mandrel and the flanged portion into the outer mandrel.

[0203] Example 9: A method according to Example 7 or 8, wherein the inner mandrel comprises an inner mandrel forming surface comprising a first cylindrical outer surface, a second cylindrical outer surface, and a recessed chamfered outer surface extending between the first cylindrical outer surface and the second cylindrical outer surface.

[0204] Example 10: A method according to Example 7, 8 or 9, wherein the outer mandrel comprises a recess defining an outer mandrel forming surface comprising a first cylindrical inner surface, a second cylindrical inner surface, and a frustoconical inner surface extending between the first cylindrical inner surface and the second cylindrical inner surface.

[0205] Example 11 : A method according to Examples 9 and 10, wherein the shape of the inner mandrel forming surface is complementary with the shape of the outer mandrel forming surface.

[0206] Example 12: A method according to Example 11 , wherein the step of inserting the inner mandrel and the flanged portion into the outer mandrel compresses the flanged portion between the inner mandrel forming surface and the outer mandrel forming surface.

[0207] Example 13: A method according to any of Examples 6 to 12, wherein at least one of the first mandrel and the second mandrel is rotated during the step of compressing the flanged portion.

[0208] Example 14: A method according to any preceding Example, wherein the second tubular portion has a first end and a second end, wherein the folded portion extends between the first end of the first tubular portion and the second end of the second tubular portion, and wherein the step of applying a third folding force positions the second end of the second tubular portion inside the cavity defined by the first tubular portion.

[0209] Example 15: A method according to Example 14, wherein the third folding force is removed while the first end of the second tubular portion remains outside the cavity defined by the first tubular portion.

[0210] Example 16: A method according to Example 14, wherein the third folding force is removed when the first end of the second tubular portion is flush with the first end of the first tubular portion.

[0211] Example 17: A method according to Example 14, wherein the third folding force is applied until the second tubular portion is positioned entirely inside the cavity defined by the first tubular portion.

[0212] Example 18: A method according to any preceding Example, wherein the third folding force is applied until an angle between the folded portion and an inner surface of the first tubular portion is less than 90 degrees. Example 19: A method according to any preceding Example, wherein the third folding force is applied until an angle between the folded portion and an outer surface of the second tubular portion is less than 90 degrees.

[0213] Example 20: A method according to any preceding Example, wherein the first tubular portion has a first length, wherein the second tubular portion has a second length, and wherein the second length is smaller than the first length.

[0214] Example 21 : A method according to Example 20, wherein the second length is less than 50 percent of the first length, less than 40 percent of the first length, less than 30 percent of the first length, less than 20 percent of the first length, or less than 10 percent of the first length.

[0215] Example 22: A method according to any preceding Example, further comprising at least one airflow aperture extending through the folded portion.

[0216] Example 23: A method according to Example 22, further comprising a step of forming the at least one airflow aperture through the tubular body before the steps of applying the first, second and third folding forces.

[0217] Example 24: A method according to Example 22 or 23, wherein the at least one airflow aperture comprises a plurality of airflow apertures.

[0218] Example 25: A method according to Example 24, wherein the airflow apertures are arranged symmetrically around the folded portion.

[0219] Example 26: A method according to any preceding Example, wherein the tubular body is formed from at least one of paper and cardboard.

[0220] Example 27: A method according to any preceding Example, wherein the tubular body is formed from a material having a grammage of between 100 grams per square metre and 700 grams per square metre, preferably between 100 grams per square metre and 400 grams per square metre.

[0221] Example 28: A method according to any preceding Example, wherein the tubular element has a length of between 10 millimetres and 30 millimetres, preferably between 15 millimetres and 25 millimetres, preferably between 15 millimetres and 20 millimetres.

[0222] Example 29: A method of forming an aerosol-generating article, the method comprising: providing a plurality of elements comprising a substrate element comprising an aerosolforming substrate and a tubular element formed according to the method of any preceding Example; and assembling the plurality of elements together in the form of a rod to form an aerosolgenerating article.

[0223] Example 30: A method of forming an aerosol-generating article, the method comprising: forming a tubular element using the method of any of Examples 1 to 28; providing a plurality of elements comprising a substrate element comprising an aerosolforming substrate and the tubular element; and assembling the substrate element and the tubular element together in the form of a rod to form an aerosol-generating article.

[0224] Example 31 : A method according to Example 29 or 30, wherein the assembling step comprises positioning the tubular element adjacent to the substrate element.

[0225] Example 32: A method according to Example 29, 30 or 31 , wherein the plurality of elements further comprises a mouthpiece element.

[0226] Example 33: A method according to Example 32, wherein the assembling step comprises positioning the tubular element between the substrate element and the mouthpiece element.

[0227] Example 34: A method according to Example 33, wherein an upstream end of the substrate element defines an upstream end of the aerosol-generating article, wherein the first end of the tubular element is adjacent a downstream end of the substrate element, wherein an upstream end of the mouthpiece element is adjacent the second end of the tubular element, and wherein a downstream end of the mouthpiece element defines a downstream end of the aerosolgenerating article.

[0228] Example 35: A method according to any of Examples 29 to 34, wherein the assembling step comprises wrapping at least one wrapper around the plurality of elements.

[0229] Example 36: A method according to any of Examples 29 to 35, wherein the aerosolgenerating article comprising a ventilation zone at a location along the tubular element.

[0230] Example 37: A method according to any of Examples 29 to 36, wherein the aerosolforming substrate is a rod of aerosol-forming substrate, and wherein the substrate element further comprises a susceptor element arranged within the rod of aerosol-forming substrate.

[0231] Example 38: A method according to Example 37, wherein the susceptor element is an elongate susceptor arranged longitudinally within the aerosol-forming substrate.

[0232] Example 39: A method according to any of Examples 29 to 38, wherein the substrate element comprises a capsule, and wherein the aerosol-forming substrate is contained within the capsule.

[0233] Example 40: A method according to Example 39, wherein the first end of the tubular element abuts a downstream end of the capsule.

[0234] Example 41 : A method according to Example 39 or 40, wherein the capsule comprises a first frangible portion at an upstream end of the capsule and a second frangible portion at a downstream end of the capsule.

[0235] Examples will now be further described with reference to the accompanying figures in which:

[0236] Figure 1 shows a cross-sectional view of an aerosol-generating article according to a first example and comprising a tubular element formed using a method according to the present disclosure; Figure 2 shows a cross-sectional view of the tubular element of the aerosol-generating article of Figure 1 ;

[0237] Figure 3 shows a perspective view of the tubular element of Figure 2;

[0238] Figures 4 to 13 show a method and apparatus for forming the tubular element of Figures 2 and 3 according to a first example of the present disclosure;

[0239] Figure 14 a cross-sectional view of an aerosol-generating article according to a second example and comprising a tubular element formed using a method according to the present disclosure;

[0240] Figure 15 shows a cross-sectional view of the tubular element of the aerosol-generating article of Figure 14;

[0241] Figure 16 shows a perspective view of the tubular element of Figure 15;

[0242] Figure 17 shows a schematic flow diagram representing a method of forming the aerosolgenerating articles of Figures 1 and 14;

[0243] Figure 18 shows a cross-sectional view of the hopper and feeding unit of Figure 17;

[0244] Figures 19 to 23 show a method and apparatus for forming the tubular element of Figures 2 and 3 according to a second example of the present disclosure; and

[0245] Figure 24 shows a double-ended tubular element formed using the method and apparatus of Figures 19 to 23.

[0246] Figure 1 shows a cross-sectional view of an aerosol-generating article 10 according to a first example. The aerosol-generating article 10 comprises a plurality of elements assembled in the form of a rod and axially aligned along a longitudinal direction 12 of the aerosol-generating article 10.

[0247] The plurality of elements comprises an upstream element 14, a substrate element 16, a tubular element 18, and a mouthpiece element 20. The aerosol-generating article 10 extends from an upstream end 15 to a downstream end 17. The aerosol-generating article 10 has an overall length of between about 60 millimetres and about 80 millimetres.

[0248] The tubular element 18 is a tubular element formed using a method according to the present disclosure. The tubular element 18 is located immediately downstream of the substrate element 16, the tubular element 18 being in longitudinal alignment with the substrate element 16. In the example of Figure 1 , the upstream end of the tubular element 18 abuts the downstream end of the substrate element 16. Figures 2 and 3 illustrate the tubular element 18 in more detail.

[0249] The tubular element 18 comprises a first tubular portion 22 and a second tubular portion 24 connected to the first tubular portion 22 by a folded portion 26 having an annular shape. The folded portion 26 extends between an upstream end 28 of the first tubular portion 22 and a downstream end 30 of the second tubular portion 24. The folded portion 26 has a linear cross- sectional shape that forms angles of less than 90 degrees with respect to an inner surface of the first tubular portion 22 and an outer surface of the second tubular portion 24. As a result of this arrangement, the downstream end 30 of the second tubular portion 24 is positioned inside the first tubular portion 22. The tubular element 18 is formed as a unitary element so that the first tubular portion 22, the second tubular portion 24 and the folded portion 26 are formed as a single piece from a continuous material.

[0250] The first tubular portion 22 defines a cavity 32 that extends all the way from the upstream end 28 of the first tubular portion 22 to a downstream end 34 of the first tubular portion 22. The cavity 32 is substantially empty, and so substantially unrestricted airflow is enabled through the cavity 32. Therefore, the first tubular portion 22 does not substantially contribute to the overall resistance-to-draw (RTD) of the aerosol-generating article 10. In other words, the RTD of the first tubular portion 22 is substantially 0 millimetres of water. The first tubular portion 22 functions as an aerosol-cooling element for the aerosol-generating article 10.

[0251] The second tubular portion 24 defines an airflow passage 36 that extends all the way from an upstream end 38 of the second tubular portion 24 to the downstream end 30 of the second tubular portion 24. The airflow passage 36 is substantially empty, and so substantially unrestricted airflow is enabled through the airflow passage 36. Therefore, the second tubular portion 24 does not substantially contribute to the overall RTD of the aerosol-generating article 10. In other words, the RTD of the second tubular portion 24 is substantially 0 millimetres of water. The second tubular portion 24 functions as a support element to prevent movement of the substrate element 16 towards the downstream end 17 of the aerosol-generating article 10. To support this function, an internal diameter 40 of the second tubular portion 24 is smaller than an internal diameter 42 of the first tubular portion 22 and smaller than an external diameter of the substrate element 16. In the particular example shown in Figures 1 to 3, the internal diameter of the first tubular portion 22 is between about 6.5 millimetres and about 7.5 millimetres, and the internal diameter of the second tubular portion 24 is between about 2.25 millimetres and about 2.75 millimetres.

[0252] The tubular element 18 has a length of between about 10 millimetres and about 20 millimetres. The first tubular portion 22 has a similar length and may define the entire length of the tubular element 18 if the second tubular portion 24 is positioned entirely within the cavity 32 defined by the first tubular portion 22. The second tubular portion 24 has a length of less than 50 percent of the length of the first tubular portion 22.

[0253] The aerosol-generating article 10 further comprises a ventilation zone 44 provided at a location along the first tubular portion 22 of the tubular element 18. The ventilation zone 44 comprises a circumferential ring of ventilation holes extending through the wall of the first tubular portion 22. Air may be drawn through the ventilation holes and through the first tubular portion 22 to achieve cooling of the stream of aerosol generated upon heating of the substrate element 16. A ventilation level of the aerosol-generating article 10 is about 25 percent.

[0254] The mouthpiece element 20 is positioned immediately downstream of the first tubular portion 22 of the tubular element 18. An upstream end of the mouthpiece element 20 abuts the downstream end 34 of the first tubular portion 22 of the tubular element 18. The mouthpiece element 20 is provided in the form of a cylindrical plug of low-density cellulose acetate. The mouthpiece element 20 has a length of about 12 millimetres and an external diameter of about 7.1 millimetres. A mouthpiece plug wrap 46 is wrapped around the mouthpiece element 20.

[0255] The substrate element 16 comprises an aerosol-forming substrate 48 of one of the types described above. The substrate element 16 is in the form of a rod comprising the aerosol-forming substrate 48. The aerosol-forming substate 48 may substantially define the structure and dimensions of the substrate element 16. A substrate plug wrap 50 is wrapped around the substrate element 16. The substrate element 16 has an external diameter of about 7.1 millimetres and a length of about 12 millimetres.

[0256] The aerosol-generating article 10 also comprises an elongate susceptor element 52 within the substrate element 16. The susceptor element 52 is arranged substantially longitudinally within the aerosol-generating substrate 48 and extends substantially parallel to the longitudinal direction 12. The susceptor element 52 is positioned in a radially central position within the substrate element 16 and extends effectively along a longitudinal axis of the substrate element 16. The susceptor element 52 extends all the way from an upstream end to a downstream end of the substrate element 16. In effect, the susceptor element 52 has substantially the same length as the substrate element 16. In the example of Figure 1 , the susceptor element 52 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 internal diameter 40 of the second tubular portion 24 is smaller than the width of the susceptor element 52 to retain the susceptor element 52 in the substrate element 16.

[0257] The upstream element 14 is located immediately upstream of the substrate element 16, the upstream element 14 being in longitudinal alignment with the substrate element 16. In the example of Figure 1 , the downstream end of the upstream element 14 abuts the upstream end of the substrate element 16. This advantageously prevents the susceptor element 52 from being dislodged and ensures the consumer cannot accidentally contact the heated susceptor element 52 after use. The upstream element 14 is provided in the form of a cylindrical plug of cellulose acetate circumscribed by an upstream plug wrap 54. The upstream element 14 has a length of about 5 millimetres.

[0258] The aerosol-generating article 10 also comprises an outer wrapper 56 circumscribing the upstream element 14, the substrate element 16 and the tubular element 18, and a tipping wrapper 58 circumscribing the mouthpiece element 20 and a part of the tubular element 18.

[0259] Figures 4 to 13 show a method and apparatus for forming the tubular element 18 according to a first example of the present disclosure. The method begins with a tubular precursor or tubular body 100 comprising a simple cardboard tube. In a first step illustrated by the three diagrams in Figure 4, a first folding force is applied to a first end 102 of the tubular body 100 with a flanging mandrel 104 to form a flanged tube 106 comprising the first tubular portion 22 and an annular flanged portion 108. The first tubular portion 22 defines the cavity 32 extending from the upstream or first end 28 of the first tubular portion 22 to the downstream or second end 34 of the first tubular portion 22. The flanged portion 108 extends from the first end 28 of the first tubular portion 22 towards a longitudinal axis of the tubular body 100. To facilitate folding of the tubular body 100 to form the flanged tube 106 the flanging mandrel 106 is rotated about its longitudinal axis during application of the first folding force to the first end 102 of the tubular body 100.

[0260] Figures 5 to 8 show an exemplary first or inner mandrel 200 and a second or outer mandrel 300 that may be used to convert the flanged tube 106 into the tubular element 18.

[0261] The inner mandrel 200 is illustrated in Figures 5 and 6, which show a perspective view and a cross-sectional view respectively of the inner mandrel 200. The inner mandrel 200 has a generally cylindrical shape and comprises a first cylindrical portion 202 defining a first cylindrical outer surface 204 and a second cylindrical portion 206 defining a second cylindrical outer surface 208. The inner mandrel 200 also defines a recessed chamfered outer surface 210 extending between the first cylindrical outer surface 204 and the second cylindrical outer surface 208. The first cylindrical outer surface 204, the second cylindrical outer surface 208 and the recessed chamfered outer surface 210 together form an inner mandrel forming surface.

[0262] The outer mandrel 300 is illustrated in Figures 7 and 8, which show a perspective view and a cross-sectional view respectively of the outer mandrel 300. The outer mandrel 300 has a generally tubular shape and comprises a recess 302 defining a first cylindrical inner surface 304 and a second cylindrical inner surface 308. The outer mandrel 300 also defines a frustoconical inner surface 310 extending between the first cylindrical inner surface 304 and the second cylindrical inner surface 308. The first cylindrical inner surface 304, the second cylindrical inner surface 308 and the frustoconical inner surface 310 together form an outer mandrel forming surface. The recess 302 is shaped so that the outer mandrel forming surface is complementary with the shape of the inner mandrel forming surface.

[0263] Figures 9 to 13 illustrate an exemplary method of using the inner and outer mandrels 200, 300 to convert the flanged tube 106 into the tubular element 18. In a first step shown in Figure 9, the flanged portion 108 of the flanged tube 106 is inserted into the recess 302 of the outer mandrel 300 and the inner mandrel 200 is inserted into the cavity 32 defined by the first tubular portion 22. In a second step shown in Figure 10, the inner and outer mandrels 200, 300 are advanced towards each other until the second cylindrical portion 206 and the edge of the frustoconical surface 310 engage the flanged portion 108 of the flanged tube 106. In a third step shown in Figure 11 , the inner and outer mandrels 200, 300 are further advanced towards each other to apply a second folding force to the flanged portion 108 of the flanged tube 106. The second folding force forms the second tubular portion 24 by compressing part of the flanged portion 108 between the second cylindrical outer surface 208 and the second cylindrical inner surface 308. In a fourth step shown in Figure 12, the inner and outer mandrels 200, 300 are further advanced towards each other to apply a third folding force to the remaining part of the flanged portion 108. The third folding force forms the folded portion 26 by compressing the remaining part of the flanged portion 108 between the recessed chamfered outer surface 210 and the frustoconical inner surface 310, which positions the downstream end 30 of the second tubular portion 24 inside the cavity 32 defined by the first tubular portion 22. Finally, in a fifth step shown in Figure 13, the inner and outer mandrels 200, 300 are withdrawn from each other to allow removal of the finished tubular element 18.

[0264] To facilitate folding of the flanged tube 106 to form the tubular element 18, at least one of the inner and outer mandrels 200, 300 is rotated about its longitudinal axis during application of the second and third folding forces.

[0265] The skilled person will appreciate that, depending on the length of the second cylindrical portion 206 and the length of the flanged portion 108, the application of the third folding force may occur before the application of the second folding force, or the application of the second and third folding forces may occur concurrently.

[0266] Figure 14 shows a cross-sectional view of an aerosol-generating article 400 according to a second example. The aerosol-generating article 400 is an inhaler article such as a dry powder inhaler. The aerosol-generating article 400 comprises an outer body 402 having a partially-closed upstream end 404 and a partially-closed downstream end 406. An upstream opening 408 is formed in the upstream end 404 of the outer body 402 and a downstream opening 410 is formed in the downstream end 406 of the outer body 402. The upstream opening 408 acts as an air inlet and the downstream opening 410 acts as an air outlet. An airflow pathway extends between the upstream opening 408 and the downstream opening 410 and passes through an interior cavity 407 of the outer body 402. An upstream portion of the interior cavity 407 of the outer body 402 near the upstream end 404 houses a substrate segment 416 in the form of a capsule containing nicotine particles.

[0267] The partially closed upstream end 404 of the outer body 402 prevents the capsule from falling out of the upstream end 404 of the outer body 402. The diameter of the capsule is larger than the diameter of the upstream opening 408 and therefore cannot pass through the upstream opening 408. A tubular element 418 is provided inside the interior cavity 407 and positioned downstream of the capsule. The tubular element 418 is a tubular element formed using a method according to the present disclosure. The tubular element 418 is fixed to an internal surface of the outer body 402 and acts as a retention plug for restricting downstream movement of the capsule to maintain the capsule in the upstream portion of the interior cavity 407.

[0268] The tubular element 418 is shown in more detail in Figures 15 and 16, which show a cross- sectional view and a perspective view respectively of the tubular element 418. The tubular element 418 is similar to the tubular element 18 described with reference to Figures 1 to 3 and therefore like reference numerals are used to designate like parts.

[0269] The tubular element 418 differs from the tubular element 18 by the addition of a plurality of airflow apertures 420 extending through the folded portion 26. The plurality of airflow apertures 420 are arranged symmetrically around the second tubular portion 24.

[0270] The second tubular portion 24 abuts a downstream end of the capsule and the inner diameter 40 of the second tubular portion 24 is smaller than an outer diameter of the capsule so that movement of the capsule towards the downstream end 406 of the outer body 402 is prevented. The inner diameter 42 of the first tubular portion 22 is larger than the inner diameter 40 of the second tubular portion so that substantially unrestricted airflow is enabled through the cavity 32.

[0271] The tubular element 418 may be formed using substantially the same method as described with reference to Figures 4 to 14 for forming the tubular element 18. The plurality of airflow apertures 420 may be formed in the tubular body 100 before folding to form the flanged tube 106. Alternatively, the airflow apertures 420 may be formed in the folded portion 26 after the tubular element 18 has been formed. The airflow apertures 420 may be formed using any suitable process. For example, the airflow apertures 420 may be formed using laser perforation.

[0272] In use, a consumer pierces the capsule via the upstream opening 408 using an external piercing tool. The piercing tool is pushed through the upstream opening 408 and into the capsule to create a hole in the capsule through which nicotine particles can exit the capsule. Substantial downstream movement of the capsule is limited by the tubular element 418. The upstream end 38 of the second tubular portion 24 abuts the capsule during piercing and holds the capsule in position to allow for easier piercing.

[0273] When a consumer inhales or draws on the downstream end 406 of the aerosol-generating article 400, air is drawn in through the upstream opening 408 and through the upstream portion of the internal cavity 407 of the outer body 402 housing the capsule. Nicotines particles exit the capsule and are entrained in the airflow through the outer body 402. The airflow laden with nicotine particles passes through the cavity 32 of the tubular element 418. The expansion in crosssection of the airflow pathway as air passes from the second tubular portion 24 into the first tubular portion 22, together with the airflow through the plurality of airflow apertures 420, may cause 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 410.

[0274] The smaller external diameter of the second tubular portion 24 compared to the first tubular portion 22 defines an annular space 426 between an external surface of the second tubular portion 24 and an internal surface of the outer body 402. The annular space 426 defines a gutter or well that collects excess nicotine particles that are released from the capsule but are not entrained the airflow when a consumer draws on the aerosol-generating article 400. The annular space 426 also collects nicotine particles that are released from the capsule when the aerosol-generating article 400 is moved around between consumer inhalations. The annular space 426 created by the tubular element 418 acts as a barrier that reduces the likelihood of the nicotine particles leaking from the aerosol-generating article 400 between consumer inhalations or between uses of the aerosol-generating article 400.

[0275] Figure 17 shows a schematic flow diagram representing a method of forming the aerosolgenerating articles of Figures 1 and 14. In a first step, a plurality of tubular bodies 100 are received in a hopper and feeding unit 502. Figures 18 shows a detailed cross-sectional view of the hopper and feeding unit 502, which comprises a hopper 520 into which the tubular bodies 100 are received. At the bottom of the hopper 520, a plurality of channels 522 feed individual tubular bodies 100 into grooves 524 for feeding to an alignment drum 504.

[0276] The alignment drum 504 receives the tubular bodies 100 from the hopper and feeding unit 502 and positions each tubular body 100 in the correct orientation before passing it to a flanging unit 506. At the flanging unit, each tubular body 100 undergoes the flanging process described above with reference to Figure 4 to form a flanged tube 106. The flanged tube 106 is then passed to a forming unit 508 where it undergoes the forming process described above with reference to Figures 9 to 13 to form a tubular element.

[0277] To form the aerosol-generating article 10 of Figure 1 , the tubular element then passes to a combining unit 510 where it is combined with the other elements of the aerosol-generating article 10, such as the substrate element 16 and the mouthpiece 20. Finally, at a laser perforation unit 512, a plurality of ventilation holes are formed to create the ventilation zone 44 on the finished aerosol-generating article 10.

[0278] Alternatively, to form the aerosol-generating article 400 of Figure 14, the tubular element passes to a laser perforation unit 514 where the airflow apertures 420 are formed in the folded portion 26 of the tubular element. Finally, at a combining unit 516, the tubular element is combined with other elements, such as the outer body 402 and the substrate element 416, to form the finished aerosol-generating article 400.

[0279] Figures 19 to 23 show a method and apparatus for forming the tubular element 18 according to a second example of the present disclosure. The method begins with a tubular precursor or tubular body 100 comprising a simple cardboard tube. In a first step illustrated by the diagram in Figure 19, the tubular body 100 is inserted into a central bore 604 of a tube holder 602. A longitudinal axis of the central bore 604 defines a longitudinal direction 603 and a radial direction 605 perpendicular to the longitudinal direction 603. The central bore 604 is shorter than the tubular body 100 so that the first end 102 of the tubular body 100 protrudes from the tube holder 602.

[0280] To facilitate the folding of the tubular body 100, preferably the tubular body 100 is provided with first and second circumferentially extending scored lines 606, 608 adjacent the first end 102 that determine the positions of the downstream end 30 of the second tubular portion 24 and the upstream end 28 of the first tubular portion 22 when the tubular body 100 has been folded to form the tubular element 18.

[0281] To apply the folding forces to the tubular body 100, the apparatus comprises a first or inner mandrel 610 and a plurality of second or outer mandrels 612. Figures 20 to 23 show cross- sectional and end views of the inner and outer mandrels 610, 612.

[0282] The inner mandrel 610 has a cylindrical shape having an outer diameter corresponding to the desired inner diameter of the second tubular portion 24. A cylindrical outer surface 611 of the inner mandrel 610 forms an inner mandrel forming surface.

[0283] Each of the outer mandrels 612 has concave inner surface 613 having a radius of curvature substantially the same as a radius of curvature of the cylindrical outer surface 611 of the inner mandrel 610. The concave inner surface 613 of each outer mandrel 612 forms an outer mandrel forming surface.

[0284] In a step illustrated in Figure 20, the inner mandrel 610 is inserted into the first end 102 of the tubular body 100 along the longitudinal direction 603 and the plurality of outer mandrels 612 are positioned around the outside of the first end 102 of the tubular body 100 so that a leading edge 614 of each outer mandrel 612 is aligned with the first circumferentially extending score line 606.

[0285] Next, in a step shown in Figure 21 , the plurality of outer mandrels 612 are moved in the radial direction 605 towards the longitudinal axis 12 to compress the first end 102 of the tubular body 100 between the inner and outer mandrels 610, 612. This step simultaneously applies a first folding force to deform the tubular body 100 about the second circumferential scored line 608 to form the folded portion 26 of the tubular element 18 and a second folding force to deform the tubular body 100 about the first circumferential scored line 606 to form the second tubular portion 24 of the tubular element 18.

[0286] In the next step shown in Figure 22, the outer mandrels 612 are advanced in the longitudinal direction 603 to apply a third folding force that rotates the folded portion 26 around the second circumferential scored line 608 until the downstream end 30 of the second tubular portion 24 is positioned inside the cavity 32 defined by the first tubular portion 22.

[0287] Finally, in the last step shown in Figure 23, the inner and outer mandrels 610, 612 are withdrawn from the tubular element 18 in both the radial and longitudinal directions 605, 603 to allow removal of the finished tubular element 18 from the tube holder 602.

[0288] The skilled person will appreciate that the radial and longitudinal movements of the outer mandrels 612 shown in Figures 21 and 22 may be performed concurrently so that the first, second and third folding forces are applied simultaneously. Similarly, the skilled person will appreciate that the simultaneous radial and longitudinal withdrawal of the inner and outer mandrels 610, 612 shown in Figure 23 may instead be performed by withdrawing the inner and outer mandrels 610, 612 in the longitudinal direction 603 first and the radial direction 605 second.

[0289] Compared to the method and apparatus described with reference to Figures 4 to 13, the plain cylindrical shape of the inner mandrel 610 allows withdrawal of the inner mandrel 610 from the tubular element 18 through the second tubular portion 24. Therefore, advantageously, the method described with reference to Figures 19 to 23 may be applied to both ends of a doublelength tubular body to form a double-ended tubular element 618 that may be cut in half at a midpoint 620 of the double-ended tubular element 618 to produce two tubular elements 18. The skilled person will appreciate that the method of Figures 19 to 23 may be applied consecutively or simultaneously to both ends of a double-length tubular body. For example, the method may be applied to both ends of a double-length tubular body by providing a tube holder 602 from which both ends of the double-length tubular body may protrude simultaneously and further providing a set of inner and outer mandrels 610, 612 at each end of the tube holder 602. Advantageously, this may double the production speed of the tubular elements 18.

Claims

Claims1. A method of forming a tubular element for an aerosol-generating article, the method comprising: providing a tubular body defining a longitudinal axis, wherein the tubular body is formed from one or more of paper, cardboard, acetate tow or polylactic acid (PLA); applying a first folding force to an end of the tubular body to fold the end of the tubular body towards the longitudinal axis to form a flanged tube comprising a first tubular portion defining a cavity extending from a first end of the first tubular portion to a second end of the first tubular portion and further comprising a flanged portion extending from the first end of the first tubular portion towards the longitudinal axis; applying a second folding force to the flanged portion to form a second tubular portion extending parallel to the longitudinal axis and a folded portion extending between the first end of the first tubular portion and the second tubular portion; and applying a third folding force to the folded portion to position the second tubular portion at least partially inside the cavity defined by the first tubular portion.

2. A method according to claim 1 , wherein the steps of applying the second folding force and applying the third folding force are performed concurrently.

3. A method according to claim 1 or 2, wherein the step of applying the first folding force comprise contacting the end of the tubular body with a flanging mandrel, optionally wherein the step of contacting the end of the tubular body with the flanging mandrel comprises contacting the end of the tubular body with a concave end face of the flanging mandrel, optionally wherein the flanging mandrel is rotated during the step of contacting the end of the tubular body with the flanging mandrel.

4. A method according to claim 1 , 2 or 3, wherein the steps of applying the second folding force and applying the third folding force comprise compressing the flanged portion between a first mandrel and a second mandrel.

5. A method according to claim 4, wherein the first mandrel is an inner mandrel and the second mandrel is an outer mandrel, and wherein the step of compressing the flanged portion comprises inserting the inner mandrel and the flanged portion into the outer mandrel.

6. A method according to claim 5, wherein the inner mandrel is positioned inside the first tubular portion during the step of inserting the inner mandrel and the flanged portion into the outer mandrel.

7. A method according to claim 5 or 6, wherein the inner mandrel comprises an inner mandrel forming surface comprising a first cylindrical outer surface, a second cylindrical outer surface, and a recessed chamfered outer surface extending between the first cylindrical outer surface and the second cylindrical outer surface.

8. A method according to claim 5, 6 or 7, wherein the outer mandrel comprises a recess defining an outer mandrel forming surface comprising a first cylindrical inner surface, a second cylindrical inner surface, and a frustoconical inner surface extending between the first cylindrical inner surface and the second cylindrical inner surface.

9. A method according to claims 7 and 8, wherein the shape of the inner mandrel forming surface is complementary with the shape of the outer mandrel forming surface, optionally wherein the step of inserting the inner mandrel and the flanged portion into the outer mandrel compresses the flanged portion between the inner mandrel forming surface and the outer mandrel forming surface.

10. A method according to claim 1 or 2, wherein the steps of applying the first folding force and applying the second folding force comprise compressing the end of the tubular body between a first mandrel and at least one second mandrel.

11. A method according to claim 10, wherein the first mandrel is an inner mandrel and the at least one second mandrel comprises a plurality of outer mandrels, and wherein the step of compressing the end of the tubular body between the first mandrel and the at least one second mandrel comprises compressing the end of the tubular body between the inner mandrel and the plurality of outer mandrels.

12. A method according to claim 11 , wherein at least part of the inner mandrel is positioned inside the tubular body during the step of compressing the end of the tubular body between the inner mandrel and the plurality of outer mandrels.

13. A method according to claim 11 or 12, wherein the inner mandrel has a cylindrical shape and a cylindrical outer surface, wherein the cylindrical outer surface forms an inner mandrel forming surface.

14. A method according to claim 13, wherein each outer mandrel comprises a concave inner surface forming an outer mandrel forming surface, and wherein the step of compressing the end of the tubular body between the inner mandrel and the plurality of outer mandrels comprisescompressing the end of the tubular body between the inner mandrel forming surface and the plurality of outer mandrel forming surfaces.

15. A method according to claim 14, wherein the cylindrical outer surface of the inner mandrel has a first radius of curvature, wherein the concave inner surface of each outer mandrel has a second radius of curvature, and wherein the first radius of curvature is the same as the second radius of curvature.

16. A method according to any of claims 10 to 15, wherein the step of applying the third folding force comprises moving each of the at least one second mandrels parallel to the longitudinal axis of the tubular body.

17. A method of forming an aerosol-generating article, the method comprising: providing a plurality of elements comprising a substrate element comprising an aerosol- forming substrate and a tubular element formed according to the method of any preceding claim; and assembling the plurality of elements together in the form of a rod to form an aerosolgenerating article.

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