AEROSOL-GENERATING ARTICLE COMPRISING UPSTREAM ELEMENT

The present invention relates to an aerosol-generating article comprising an aerosolgenerating substrate for generating an inhalable aerosol upon heating. The invention also relates to an aerosol-generating system comprising the aerosol-generating article and an aerosolgenerating device configured to heat the aerosol-generating article.

Aerosol-generating articles in which an aerosol-generating substrate comprising aerosolgenerating material, such as a tobacco-containing material, is heated rather than combusted are known in the art. An aim of such ‘heated’ aerosol-generating articles is to reduce known harmful smoke constituents of the type produced by the combustion and pyrolytic degradation of tobacco in conventional cigarettes.

Typically, in heated aerosol-generating articles an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-generating substrate. In use, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source to the aerosol-generating substrate and are entrained in air drawn through the aerosolgenerating article. As the released compounds cool, they condense to form an aerosol that is inhaled by the user.

One known type of heated aerosol-generating article, commonly referred to as a heat-not- burn tobacco product or heated tobacco product, comprises a solid aerosol-generating substrate comprising tobacco material, which is heated to produce an inhalable aerosol.

A number of handheld aerosol-generating devices configured to heat aerosol-generating substrates of heated aerosol-generating articles are known in the art. These include electrically- operated aerosol-generating devices in which an aerosol is generated by the transfer of heat from one or more electrical heating elements of the aerosol-generating device to the aerosolgenerating substrate of the heated aerosol-generating article. Known handheld electrically operated aerosol-generating devices typically comprise a battery, control electronics and one or more electrical heating elements for heating the aerosol-generating substrate of a heated aerosolgenerating article designed specifically for use with the aerosol-generating device.

Some known electrically heated aerosol-generating devices comprise an internal heating element that is configured to be inserted into the aerosol-generating substrate of a heated aerosol-generating article. For example, WO 2013/098410 A2 discloses an aerosol-generating system comprising an aerosol-generating article and an electrically-operated aerosol-generating device comprising a heating element in the form of a blade that is inserted into the aerosolgenerating substrate of the aerosol-generating article.

Other known electrically-operated aerosol-generating devices comprise one or more external heating elements. For example, WO 2020/115151 A1 discloses an aerosol-generating system comprising an aerosol-generating article and an electrically-operated aerosol-generating device comprising an external heating element that circumscribes the periphery of the aerosolgenerating article.

Electrically-operated aerosol-generating devices comprising an inductor configured to inductively heat aerosol-generating substrates of heated aerosol-generating articles are also known. For example, WO 2015/176898 A1 discloses an aerosol-generating system comprising an aerosol-generating article comprising an elongate susceptor in thermal contact with the aerosol-generating substrate and an electrically-operated aerosol-generating device having an inductor for heating the aerosol-generating substrate. In use, the fluctuating or alternating electromagnetic field produced by the inductor induces eddy currents in the susceptor, causing the susceptor to heat up as a result of one or both of resistive losses (Joule heating) and, where the susceptor is magnetic, hysteresis loses. Heat generated in the susceptor is transferred to the aerosol-generating substrate by conduction.

Heated aerosol-generating articles designed for use with an electrically-operated aerosolgenerating device are typically inserted into a cavity of the aerosol-generating device in order to be heated. This may cause aerosol-generating material in the aerosol-generating substrate of the aerosol-generating article to be dislodged. Heating of the aerosol-generating substrate during use of the aerosol-generating article may result in drying of aerosol-generating material in the aerosol-generating substrate. This may make the aerosol-generating material more prone to dislodgement. During use of the aerosol-generating article, aerosol-generating material dislodged from the aerosol-generating substrate may fall out of the aerosol-generating article. As a result, the amount and location of aerosol-generating material in the aerosol-generating substrate may vary during use of the aerosol-generating article. This may adversely impact the quality and consistency of aerosol delivered to a user. During use of the aerosol-generating article, aerosol-generating material dislodged from the aerosol-generating substrate may fall into the cavity of the aerosol-generating device. Aerosol-generating material dislodged from the aerosol-generating substrate of the aerosol-generating article that falls into the cavity of the aerosol-generating device may prevent or inhibit optimal functioning of the aerosol-generating device.

It would be desirable to provide an aerosol-generating article for use with an aerosolgenerating device in which the quality and consistency of aerosol delivered to a user is improved compared to known heated tobacco products. It would be desirable to provide an aerosolgenerating article for use with an aerosol-generating device that allows optimal functioning of the aerosol-generating device.

The present disclosure relates to an aerosol-generating article comprising an aerosolgenerating substrate. The aerosol-generating article may comprise an upstream element located upstream of the aerosol-generating substrate. The upstream element may comprise a tubular portion. The tubular portion may define an inner region of the upstream element. The upstream element may comprise a convoluted sheet. The convoluted sheet may define a plurality of longitudinally extending channels in the inner region. The convoluted sheet may have a basis weight of less than or equal to about 100 grams per square metre.

According to a first aspect of the invention, there is provided an aerosol-generating article comprising an aerosol-generating substrate and an upstream element located upstream of the aerosol-generating substrate, wherein the upstream element comprises: a tubular portion defining an inner region of the upstream element, and a convoluted sheet defining a plurality of longitudinally extending channels in the inner region, wherein the convoluted sheet has a basis weight of less than or equal to about 100 grams per square metre.

The present disclosure also relates to an aerosol-generating system. The aerosolgenerating system may comprise an aerosol-generating article as described above. The aerosolgenerating system may comprise an aerosol-generating device. The aerosol-generating device may be configured to heat the aerosol-generating substrate of the aerosol-generating article. The aerosol-generating device may comprise a housing. The housing may define a cavity. The cavity may be configured to receive the aerosol-generating article.

According to a second aspect of the invention, there is provided an aerosol-generating system comprising: an aerosol-generating article according to the first aspect of the invention; and an aerosol-generating device configured to heat the aerosol-generating substrate of the aerosol-generating article, wherein the aerosol-generating device comprises a housing defining a cavity configured to receive the aerosol-generating article.

As used herein with reference to the invention, the term “aerosol-generating article” is used to describe an article comprising an aerosol-generating substrate that is heated to generate an inhalable aerosol for delivery to a user.

As used herein with reference to the invention, the term “aerosol-generating substrate” is used to describe a substrate comprising aerosol-generating material that is capable of releasing upon heating volatile compounds that can generate an aerosol.

As used herein with reference to the invention, the term “aerosol” is used to describe a dispersion of solid particles, or liquid droplets, or a combination of solid particles and liquid droplets, in a gas. The aerosol may be visible or invisible. The aerosol may include vapours of substances that are ordinarily liquid or solid at room temperature as well as solid particles, or liquid droplets, or a combination of solid particles and liquid droplets.

As used herein with reference to the invention, the term “aerosol-generating device” is used to describe a device that interacts with the aerosol-generating substrate of the aerosolgenerating article to generate an aerosol.

Aerosol-generating articles according to the invention have a proximal end through which, in use, an aerosol exits the aerosol-generating article for delivery to a user. The proximal end of the aerosol-generating article may also be referred to as the downstream end or mouth end of the aerosol-generating article. In use, a user draws directly or indirectly on the proximal end of the aerosol-generating article in order to inhale an aerosol generated by the aerosol-generating article.

Aerosol-generating articles according to the invention have a distal end. The distal end is opposite the proximal end. The distal end of the aerosol-generating article may also be referred to as the upstream end of the aerosol-generating article.

Components of aerosol-generating articles according to the invention may be described as being upstream or downstream of one another based on their relative positions between the proximal end of the aerosol-generating article and the distal end of the aerosol-generating article.

As used herein with reference to the invention, the term “longitudinal” is used to describe the direction between the upstream end and the downstream end of the aerosol-generating article. During use, air is drawn through the aerosol-generating article in the longitudinal direction.

As used herein with reference to the invention, the term “length” is used to describe the maximum dimension of the aerosol-generating article or a component of the aerosol-generating article in the longitudinal direction.

As used herein with reference to the invention, the term “transverse” is used to describe the direction perpendicular to the longitudinal direction. Unless otherwise stated, references to the “cross-section” of the aerosol-generating article or a component of the aerosol-generating article refer to the transverse cross-section.

As used herein with reference to the invention, the term “width” denotes the maximum dimension of the aerosol-generating article or a component of the aerosol-generating article in a transverse direction. Where the aerosol-generating article has a substantially circular crosssection, the width of the aerosol-generating article corresponds to the diameter of the aerosolgenerating article. Where a component of the aerosol-generating article has a substantially circular cross-section, the width of the component of the aerosol-generating article corresponds to the diameter of the component of the aerosol-generating article.

As used herein with reference to the invention, the term “tubular portion” is used to describe a generally cylindrical portion having a lumen along a longitudinal axis thereof. The tubular portion may have a substantially circular, oval or elliptical cross-section. The inner region of the upstream element corresponds to the lumen of the tubular portion. The lumen may have a substantially circular, oval or elliptical cross-section.

As used herein with reference to the invention, the term “sheet” is used to describe a laminar element having a width and a length substantially greater than a thickness thereof.

As discussed used herein with reference to the invention, the term “convoluted sheet” is used to describe a sheet comprising a plurality of turns. Unless otherwise stated, references to properties of the convoluted sheet refer to properties of the sheet in its convoluted form in the upstream element of the aerosol-generating article.

Unless otherwise stated, references to properties of the sheet refer to properties of the sheet in its unconvoluted form.

It will be appreciated that some properties of the sheet may be the same in both its convoluted form and unconvoluted form. For example, the basis weight, weight, cross-sectional area, surface area, and length of the convoluted sheet are the same as the basis weight, weight, cross-sectional area, surface area, and length of the sheet in its unconvoluted form.

As used herein with reference to the invention, the basis weight of the convoluted sheet is the total weight of the convoluted sheet divided by the surface area of the convoluted sheet. Where the convoluted sheet is formed from a rectangular sheet, the surface area of the convoluted sheet is the same as the width of the rectangular sheet multiplied by the length of the rectangular sheet. For example, where the convoluted sheet is formed from a rectangular sheet having a width of about 170 millimetres and a length of about 5 millimetres, the surface area of the convoluted sheet is about 850 square millimetres.

Aerosol-generating articles according to the first aspect invention comprise an upstream element comprising a tubular portion defining an inner region of the upstream element, and a convoluted sheet defining a plurality of longitudinally extending channels in the inner region, wherein the convoluted sheet has a basis weight of less than or equal to about 100 grams per square metre. Inclusion of such an upstream element may advantageously reduce or prevent aerosol-generating material being dislodged from the aerosol-generating substrate during storage, transportation and use of the aerosol-generating article while providing an acceptable resistance to draw (RTD). Inclusion of such an upstream element may advantageously reduce or prevent any aerosol-generating material dislodged from the aerosol-generating substrate from falling into a cavity of an aerosol-generating device during use of the aerosol-generating article. Inclusion of such an upstream element may advantageously restrict or prevent longitudinal movement of the aerosol-generating substrate during storage, transportation and use of the aerosol-generating article.

The convoluted sheet partitions the inner region of the upstream element into a plurality of longitudinally extending channels along which air may be drawn through the upstream element. The convoluted sheet may thereby reduce the cross-sectional area of empty space in the upstream element that aerosol-generating material in the aerosol-generating substrate may be dislodged into while providing an acceptable resistance to draw (RTD). This may be particularly advantageous where the aerosol-generating substrate comprises a plurality of shreds, pellets, or granules of aerosol-generating material. Any aerosol-generating material dislodged from the aerosol-generating substrate must travel upstream through the plurality of longitudinally extending channels defined by the convoluted sheet in order to exit the upstream element and the aerosol-generating article. The convoluted sheet may thereby prevent or restrict aerosol-generating material dislodged from the aerosol-generating substrate from falling into a cavity of an aerosol-generating device during use of the aerosol-generating article.

Inclusion of a convoluted sheet having a basis weight of less than or equal to about 100 grams per square metre may enable the convoluted sheet to have a larger cross-sectional area while retaining an appropriate total weight of the upstream element. The convoluted sheet may thereby partition the inner region of the upstream element into a greater number of longitudinally extending channels, while retaining an appropriate total weight of the upstream element.

The convoluted sheet may advantageously act as a barrier to prevent or restrict longitudinal movement of the aerosol-generating substrate during storage, transportation and use of the aerosol-generating article.

Accordingly, the provision of an aerosol-generating article comprising an upstream element comprising a tubular portion defining an inner region of the upstream element, and a convoluted sheet defining a plurality of longitudinally extending channels in the inner region, wherein the convoluted sheet has a basis weight of less than or equal to about 100 grams per square metre in accordance with the first aspect of the invention may improve the quality and consistency of aerosol delivered to a user compared to known heated tobacco products, and may allow optimal functioning of the aerosol-generating device of an aerosol-generating system in accordance with the second aspect of the invention.

The convoluted sheet comprises a plurality of turns. Preferably, the convoluted sheet comprises a plurality of non-concentric turns.

The convoluted sheet defines a plurality of longitudinally extending channels in the inner region of the upstream element. The convoluted sheet may have been one or more of crimped, folded, gathered, and pleated to define the plurality of longitudinally extending channels.

As used herein with reference to the invention, the term “crimped” denotes a convoluted sheet having a plurality of substantially parallel ridges or corrugations. Preferably, where the convoluted sheet has been crimped, the substantially parallel ridges or corrugations of the convoluted sheet extend in a longitudinal direction of the aerosol-generating article.

As used herein with reference to the invention, the term “gathered” denotes that a sheet is compressed or constricted substantially transversely relative to a longitudinal axis of the aerosol-generating article. Preferably, the convoluted sheet has been crimped. This may advantageously reduce the variation in the cross-sectional area of the plurality of longitudinally extending channels defined by the convoluted sheet in the inner region of the upstream element.

Inclusion of a convoluted sheet that has been crimped in the upstream element may advantageously avoid or reduce the presence of longitudinally extending channels having a very large cross-sectional area in the inner region of the upstream element. The presence of longitudinally extending channels having a very large cross-sectional area in the inner region of the upstream element may adversely affect the ability of the upstream element to prevent or restrict upstream movement of aerosol-generating material from the aerosol-generating substrate.

Inclusion of a convoluted sheet that has been crimped in the upstream element may advantageously avoid or reduce the presence of longitudinally extending channels having a very small cross-sectional area in the inner region of the upstream element. The presence of longitudinally extending channels having a very small cross-sectional area in the inner region of the upstream element may increase the RTD of the upstream element beyond an acceptable or desired level.

Where the convoluted sheet has been crimped, adjacent ridges or corrugations of the convoluted sheet may be spaced apart from each other by less than or equal to about 1.2 millimetres, less than or equal to about 1 millimetre, or less than or equal to about 0.8 millimetres. For example, adjacent ridges or corrugations may be spaced apart from each other by less than or equal to about 0.5 millimetres. The spacing between adjacent ridges or corrugations may be selected based on a desired size of the plurality of longitudinally extending channels.

The convoluted sheet may have been crimped and then gathered. That is, the convoluted sheet may be a crimped and gathered sheet.

At least some of the plurality of longitudinally extending channels may be defined solely by the convoluted sheet.

At least some of the plurality of longitudinally extending channels may be defined by the convoluted sheet and the tubular portion. For example, one or more longitudinally extending channels adjacent to the tubular portion of the upstream element may be defined by the convoluted sheet and the tubular portion. The convoluted sheet may contact the tubular portion along the longitudinal direction to define a longitudinally extending channel.

The convoluted sheet is located in the inner region of the upstream element.

The convoluted sheet may extend part way along the length of the upstream element.

The convoluted sheet may extend from the downstream end of the upstream element towards the upstream end of the upstream element. This may advantageously assist in preventing or restricting upstream movement of aerosol-generating material from the aerosolgenerating substrate.

The convoluted sheet may extend from the upstream end of the upstream element towards the downstream end of the upstream element. This may advantageously assist in preventing aerosol-generating material dislodged from the aerosol-generating substrate from falling out of the upstream end of the aerosol-generating article.

Preferably, the convoluted sheet extends from the upstream end of the upstream element to the downstream end of the upstream element. That is, preferably the convoluted sheet extends along the entire length of the upstream element.

The length of the convoluted sheet may be substantially the same as the length of the upstream element. This may advantageously simplify manufacturing of the upstream element. For example, this may advantageously enable multiple upstream elements to be produced from a single continuous rod.

The plurality of longitudinally extending channels may extend from the downstream end of the upstream element towards the upstream end of the upstream element.

The plurality of longitudinally extending channels may extend from the upstream end of the upstream element towards the downstream end of the upstream element.

The plurality of longitudinally extending channels preferably extend from the upstream end of the upstream element to the downstream end of the upstream element. That is, the plurality of longitudinally extending channels preferably extend along the entire length of the upstream element.

The convoluted sheet has a basis weight of less than or equal to about 100 grams per square metre. The convoluted sheet may have a basis weight of less than or equal to about 80 grams per square metre, less than or equal to about 70 grams per square metre, or less than or equal to about 50 grams per square metre.

The convoluted sheet may have a basis weight of at least about 10 grams per square metre, at least about 15 grams per square metre, or at least about 20 grams per square metre.

The convoluted sheet may have a basis weight of between about 10 grams per square metre and about 100 grams per square metre, between about 10 grams per square metre and about 80 grams per square metre, between about 10 grams per square metre and about 70 grams per square metre, or between about 10 grams per square meter and about 50 grams per square metre.

The convoluted sheet may have a basis weight of between about 15 grams per square metre and about 100 grams per square metre, between about 15 grams per square metre and about 80 grams per square metre, between about 15 grams per square metre and about 70 grams per square metre, or between about 15 grams per square meter and about 50 grams per square metre. The convoluted sheet may have a basis weight of between about 20 grams per square metre and about 100 grams per square metre, between about 20 grams per square metre and about 80 grams per square metre, between about 20 grams per square metre and about 70 grams per square metre, or between about 20 grams per square meter and about 50 grams per square metre.

The basis weight of the convoluted sheet may be selected based on a balance between the ability of the upstream element to reduce or prevent aerosol-generating material being dislodged from the aerosol-generating substrate during storage, transportation and use of the aerosol-generating article and the total weight of the upstream element.

The basis weight of the convoluted sheet may be selected such that the convoluted sheet is able to resist deformation during storage, transportation and use of the aerosol-generating article.

The convoluted sheet may have a weight of less than or equal to about 100 milligrams, less than or equal to about 75 milligrams, or less than or equal to about 50 milligrams.

The convoluted sheet may have a weight of at least about 10 milligrams, at least about 15 milligrams, or at least about 20 milligrams.

The convoluted sheet may have a weight of between about 10 milligrams and about 100 milligrams, between about 10 milligrams and about 75 milligrams, or between about 10 milligrams and about 50 milligrams.

The convoluted sheet may have a weight of between about 15 milligrams and about 100 milligrams, between about 15 milligrams and about 75 milligrams, or between about 15 milligrams and about 50 milligrams.

The convoluted sheet may have a weight of between about 20 milligrams and about 100 milligrams, between about 20 milligrams and about 75 milligrams, or between about 20 milligrams and about 50 milligrams.

The weight of the convoluted sheet may be selected based on a desired cross-sectional area of the convoluted sheet and a desired total weight of the upstream element

The convoluted sheet may have an average weight per unit length of less than or equal to about 20 milligrams per millimetre, less than or equal to about 15 milligrams per millimetre, or less than or equal to about 10 milligrams per millimetre.

As used herein with reference to the invention, the average weight per unit length of the convoluted sheet is equal to the weight of the convoluted sheet divided by the length of the convoluted sheet. For example, where the convoluted sheet has a weight of 25 milligrams and a length of 5 millimetres, the average weight per unit length of the convoluted sheet is 5 milligrams per millimetre. The convoluted sheet may have an average weight per unit length of at least about 2 milligrams per millimetre, at least about 3 milligrams per millimetre, or at least about 4 milligrams per millimetre.

The convoluted sheet may have an average weight per unit length of between about

2 milligrams per millimetre and about 20 milligrams per millimetre, between about 2 milligrams per millimetre and about 15 milligrams per millimetre, or between about2 milligrams per millimetre and about 10 milligrams per millimetre.

The convoluted sheet may have an average weight per unit length of between about

3 milligrams per millimetre and about 20 milligrams per millimetre, between about 3 milligrams per millimetre and about 15 milligrams per millimetre, or between about 3 milligrams per millimetre and about 10 milligrams per millimetre.

The convoluted sheet may have an average weight per unit length of between about

4 milligrams per millimetre and about 20 milligrams per millimetre, between about 4 milligrams per millimetre and about 15 milligrams per millimetre, or between about 4 milligrams per millimetre and about 10 milligrams per millimetre.

The convoluted sheet may have an average weight per unit volume of the inner region of less than or equal to about 500 micrograms per cubic millimetre, less than or equal to about 400 micrograms per cubic millimetre, or less than or equal to about 250 micrograms per cubic millimetre.

As used herein with reference to the invention, the average weight of the convoluted sheet per unit volume of the inner region is the weight of the convoluted sheet divided by the volume of the inner region. For example, where the convoluted sheet has a weight of 25 milligrams and the inner region has a volume of 200 cubic millimetres, the average weight of the convoluted sheet per unit volume of the inner region is about 125 micrograms per cubic millimetre.

The convoluted sheet may have an average weight per unit volume of the inner region of at least about 50 micrograms per cubic millimetre, at least about 75 micrograms per cubic millimetre, or at least about 100 micrograms per cubic millimetre.

The convoluted sheet may have an average weight per unit volume of the inner region of between about 50 micrograms per cubic millimetre and about 500 micrograms per cubic millimetre, between about 50 micrograms per cubic millimetre and about 400 micrograms per cubic millimetre, or between about 50 micrograms per cubic millimetre and about 250 micrograms per cubic millimetre.

The convoluted sheet may have an average weight per unit volume of the inner region of between about 75 micrograms per cubic millimetre and about 500 micrograms per cubic millimetre, between about 75 micrograms per cubic millimetre and about 400 micrograms per cubic millimetre, or between about 75 micrograms per cubic millimetre and about 250 micrograms per cubic millimetre. The convoluted sheet may have an average weight per unit volume of the inner region of between about 100 micrograms per cubic millimetre and about 500 micrograms per cubic millimetre, between about 100 micrograms per cubic millimetre and about 400 micrograms per cubic millimetre, or between about 100 micrograms per cubic millimetre and about 250 micrograms per cubic millimetre.

The convoluted sheet may have an average weight per unit volume of the inner region less than a density of the aerosol-generating substrate.

The sheet may have a thickness of less than or equal to about 300 micrometres, less than or equal to about 200 micrometres, or less than or equal to about 150 micrometres.

The sheet may have a thickness of at least about 30 micrometres, at least about 45 micrometres, at least about 60 micrometres.

The sheet may have a thickness of between about 30 micrometres and about 300 micrometres, between about 30 micrometres and about 200 micrometres, or between about 30 micrometres and about 150 micrometres.

The sheet may have a thickness of between about 45 micrometres and about 300 micrometres, between about 45 micrometres and about 200 micrometres, or between about 45 micrometres and about 150 micrometres.

The sheet may have a thickness of between about 60 micrometres and about 300 micrometres, between about 60 micrometres and about 200 micrometres, or between about 60 micrometres and about 150 micrometres.

The thickness of the sheet may be selected to enable one or more of crimping, gathering, pleating, and folding of the sheet. The thickness of the sheet may be selected based on a desired cross-sectional area of the convoluted sheet.

The convoluted sheet may have a cross-sectional area of at least about 5 square millimetres, at least about 8 square millimetres, or at least about 10 square millimetres .

The cross-sectional area of the convoluted sheet is the same as the cross-sectional area of the sheet in its unconvoluted form. The cross-sectional area of the convoluted sheet is the thickness of the sheet multiplied by the width of the sheet in that cross-section.

The convoluted sheet may have a cross-sectional area of less than or equal to about 30 square millimetres, less than or equal to about 25 square millimetres, or less than or equal to about 20 square millimetres.

The convoluted sheet may have a cross-sectional area of between about 5 square millimetres and about 30 square millimetres, between about 5 square millimetres and about 25 square millimetres, or between about 5 square millimetres and about 20 square millimetres.

The convoluted sheet may have a cross-sectional area of between about 8 square millimetres and about 30 square millimetres, between about 8 square millimetres and about 25 square millimetres, or between about 8 square millimetres and about 20 square millimetres. The convoluted sheet may have a cross-sectional area of between about 10 square millimetres and about 30 square millimetres, between about 10 square millimetres and about 25 square millimetres, or between about 10 square millimetres and about 20 square millimetres.

Preferably, the cross-sectional area of the convoluted sheet is substantially constant along the length of the convoluted sheet.

The convoluted sheet may have a surface area of at least about 250 square millimetres, at least about 400 square millimetres, or at least about 600 square millimetres.

The convoluted sheet may have a surface area of less than or equal to about 1500 square millimetres, less than or equal to about 1350 square millimetres, or less than or equal to about 1250 square millimetres.

The convoluted sheet may have a surface area of between about 250 square millimetres and about 1500 square millimetres, between about 250 square millimetres and about 1350 square millimetres, or between about 250 square millimetres and about 1250 square millimetres.

The convoluted sheet may have a surface area of between about 400 square millimetres and about 1500 square millimetres, between about 400 square millimetres and about 1350 square millimetres, or between about 400 square millimetres and about 1250 square millimetres.

The convoluted sheet may have a surface area of between about 600 square millimetres and about 1500 square millimetres, between about 600 square millimetres and about 1350 square millimetres, or between about 600 square millimetres and about 1250 square millimetres.

The surface area of the convoluted sheet may be selected based on a desired cross- sectional area of the convoluted sheet. The surface area of the convoluted sheet may be selected based on a desired RTD of the upstream element.

The convoluted sheet may have an average surface area per unit length of at least about 50 square millimetres per millimetre, at least about 80 square millimetres per millimetre, or at least about 120 square millimetres per millimetre.

As used herein with reference to the invention, the average surface area per unit length of the convoluted sheet is equal to the surface area of the convoluted sheet divided by the length of the convoluted sheet. For example, where the convoluted sheet has a surface area of 850 square millimetres and a length of 5 millimetres, the average surface area per unit length of the convoluted sheet is 170 square millimetres per millimetre.

The convoluted sheet may have an average surface area per unit length of less than or equal to about 300 square millimetres per millimetre, less than or equal to about 270 square millimetres per millimetre, or less than or equal to about 250 square millimetres per millimetre. The convoluted sheet may have an average surface area per unit length of between about 50 square millimetres per millimetre and about 300 square millimetres per millimetre, between about 50 square millimetres per millimetre and about 270 square millimetres per millimetre, or between about 50 square millimetres per millimetre and about 250 square millimetres per millimetre.

The convoluted sheet may have an average surface area per unit length of between about 80 square millimetres per millimetre and about 300 square millimetres per millimetre, between about 80 square millimetres per millimetre and about 270 square millimetres per millimetre, or between about 80 square millimetres per millimetre length and about 250 square millimetres per millimetre.

The convoluted sheet may have an average surface area per unit length of between about 120 square millimetres per millimetre and about 300 square millimetres per millimetre, between about 120 square millimetres per millimetre and about 270 square millimetres per millimetre, or between about 120 square millimetres and about 250 square millimetres per millimetre.

The convoluted sheet may have a length of at least about 2 millimetres, at least about 3 millimetres, or at least about 4 millimetres.

The convoluted sheet may have a length of less than or equal to about 10 millimetres, less than or equal to about 8 millimetres, or less than or equal to about 6 millimetres.

The convoluted sheet may have a length of between about 2 millimetres and about 10 millimetres, between about 2 millimetres and about 8 millimetres, or between about

2 millimetres and about 6 millimetres.

The convoluted sheet may have a length of between about 3 millimetres and about 10 millimetres, between about 3 millimetres and about 8 millimetres, or between about

3 millimetres and about 6 millimetres.

The convoluted sheet may have a length of between about 4 millimetres and about 10 millimetres, between about 4 millimetres and about 8 millimetres, or between about

4 millimetres and about 6 millimetres.

For example, the convoluted sheet may have a length of about 5 millimetres.

Preferably, the length of the convoluted sheet is substantially the same as the length of the upstream element.

Where aerosol-generating material is dislodged from the aerosol-generating substrate into one of the plurality of longitudinally extending channels, the dislodged aerosol-generating material may block the longitudinally extending channel to reduce or prevent further aerosol-generating material being dislodged into the same longitudinally extending channel. Increasing the length of the plurality of longitudinally extending channels may enhance the ability of the upstream element to reduce or prevent further aerosol-generating material being dislodged into the plurality of longitudinally extending channels during storage, transportation and use of the aerosol- generating article. Increasing the length of the plurality of longitudinally extending channels may also increase the likelihood that any aerosol-generating material dislodged into the plurality of longitudinally extending channels is retained in the plurality of longitudinally extending channels.

Increasing the length of the plurality of longitudinally extending channels may increase the RTD of the upstream element.

The length of the sheet may be selected based on a balance between the ability of the upstream element to prevent or restrict upstream movement of aerosol-generating material in the aerosol-generating substrate and the RTD of the upstream element.

The sheet may have a width of at least about 50 millimetres, at least about 80 millimetres, or at least about 120 millimetres.

The sheet may have a width of less than or equal to about 300 millimetres, less than or equal to about 270 millimetres, or less than or equal to about 250 millimetres.

The sheet may have a width of between about 50 millimetres and about 300 millimetres, between about 50 millimetres and about 270 millimetres, or between about 50 millimetres and about 250 millimetres.

The sheet may have a width of between about 80 millimetres and about 300 millimetres, between about 80 millimetres and about 270 millimetres, or between about 80 millimetres and about 250 millimetres.

The sheet may have a width of between about 120 millimetres and about 300 millimetres, between about 120 millimetres and about 270 millimetres, or between about 120 millimetres and about 250 millimetres.

The width of the sheet and the thickness of the sheet determine the cross-sectional area of the sheet and hence the cross-sectional area of the corresponding convoluted sheet. Increasing the width of the sheet may reduce the total cross-sectional area of the plurality of longitudinally extending channels. This may enhance the ability of the upstream element to reduce or prevent aerosol-generating material being dislodged from the aerosol-generating substrate during storage, transportation and use of the aerosol-generating article. This may also increase the RTD of the upstream element. The width of the sheet may be selected based on a balance between the ability of the upstream element to prevent or restrict upstream movement of aerosol-generating material and the RTD of the upstream element.

Preferably, the sheet does not substantially contract upon exposure to heat.

The sheet may have a linear shrinkage rate of less than or equal to about 4 percent, less than or equal to about 3 percent, less than or equal to about 2 percent, less than or equal to about 1.5 percent, less than or equal to about 1 percent, less than or equal to about 0.75 percent, or less than or equal to about 0.5 percent as measured in accordance with Test Method A described herein. The sheet may have a linear shrinkage rate of about 0 percent as measured in accordance with Test Method A described herein. As used herein with reference to the invention, the term “linear shrinkage rate” is used to describe an average reduction in the length and width of the sheet after exposure to heat and is expressed as a percentage of the original length and width of the sheet prior to exposure to heat.

The sheet may have an area shrinkage rate of less than or equal to about 8 percent, less than or equal to about 6 percent, less than or equal to about 3 percent, less than or equal to about 2 percent, less than or equal to about 1 .5 percent, or less than or equal to about 1 percent as measured in accordance with Test Method A described herein. The sheet may have an area shrinkage rate of about 0 percent as measured in accordance with Test Method A described herein.

As used herein with reference to the invention, the term “area shrinkage rate” is used to describe an average reduction in the area of the sheet after exposure to heat and is expressed as a percentage of the original area of the sheet prior to exposure to heat.

A sheet that is more resistant to contraction under exposure to heat has a smaller linear shrinkage rate and a smaller area shrinkage rate.

Test Method A:

Five square samples of the sheet, each having a side length of 10 millimetres, are conditioned at 23 °C +/- 2 °C in air at 50% +/- 5% relative humidity for at least 40 hours.

Then, the samples are heated in an oven for 5 minutes at 120 °C +/- 2 °C.

The samples are then removed from the oven and cooled down to 23 °C +/- 2 °C.

Then, the side lengths of each of the five samples are measured. From the measured values, an average side length and an average area are determined. The average side length is determined by the sum of the measured side lengths of each of the five samples in units of millimetres divided by twenty. The area of each of the five samples is calculated by multiplying the measured side lengths of two adjacent sides of each of the five samples. The average area is determined by the sum of the calculated areas of each of the five samples in units of square millimetres divided by five.

The linear shrinkage rate of the sheet is given by:

(10 — average side length)

Linear shrinkage rate (%) = x 100%

10

The area shrinkage rate of the sheet is given by:

(100 — average area)

Area shrinkage rate (%) = x 100% lob

Preferably, the convoluted sheet is formed from a heat resistant material. For example, the convoluted sheet may be formed from a material that resists temperatures of up to 350 degrees Celsius. This may advantageously help to ensure that the upstream element is not adversely affected by heating of the aerosol-generating substrate during use of the aerosolgenerating article. For example, forming the convoluted sheet from a heat resistant material may advantageously help to ensure that the convoluted sheet and the upstream element do not significantly deform during use of the aerosol-generating article. This may advantageously result in the RTD of the upstream element remaining substantially constant throughout use of the aerosol-generating article.

Forming the convoluted sheet from a heat resistant material may advantageously reduce the risk of the convoluted sheet being dislodged from the upstream element or the aerosolgenerating article during storage, transportation and use of the aerosol-generating article.

Due to minimal or no change in the dimensions of the upstream element after use of the aerosol-generating article, upon removal of the used aerosol-generating article from a cavity of an aerosol-generating device, the upstream element may act as a cleaning tool to clean the cavity of the aerosol-generating device.

The convoluted sheet may be formed from any suitable material. Suitable materials include, but are not limited to: paper based materials, such as paper and cardboard; and polylactic acid (PLA).

Preferably, the convoluted sheet is formed from a biodegradable material.

Preferably, the convoluted sheet is formed from a paper-based material. That is, preferably the convoluted sheet is a convoluted sheet of paper-based material.

More preferably the convoluted sheet is formed from paper. That is, more preferably the convoluted sheet is a convoluted paper sheet. A paper sheet may be suitably heat resistant. A paper sheet may not substantially contract upon exposure to heat.

An upstream element comprising a convoluted paper sheet may exhibit better heat resistance than, for example, a plug of cellulose acetate.

The convoluted sheet may comprise a flame retardant coating. The flame retardant coating may prevent one or both of scorching and charring of the convoluted sheet during use of the aerosol-generating article.

The flame retardant coating may comprise one or more flame retardant compounds.

Suitable flame retardant compounds are known in the art.

The flame retardant composition may comprise a polymer and a mixed salt based on at least one mono, di- and/or tri-carboxylic acid, at least one polyphosphoric, pyrophosphoric and/or phosphoric acid, and a hydroxide or a salt of an alkali or an alkaline earth metal, where the at least one mono, di- and/or tri-carboxylic acid and the hydroxide or salt form a carboxylate and the at least one polyphosphoric, pyrophosphoric and/or phosphoric acid and the hydroxide or salt form a phosphate. The flame retardant composition may further comprise a carbonate of an alkali or an alkaline earth metal.

The flame retardant composition may comprise cellulose modified with at least one C10 or higher fatty acid, tall oil fatty acid (TOFA), phosphorylated linseed oil, phosphorylated downstream corn oil. The at least one C10 or higher fatty acid may be selected from the group consisting of capric acid, myristic acid, palmitic acid, and combinations thereof.

The plurality of longitudinally extending channels provide an airflow pathway through the upstream element.

As used herein with reference to the invention, the term “airflow pathway” is used to describe a route along which air may be drawn through the aerosol-generating article or a component thereof.

Preferably, the plurality of longitudinally extending channels are empty.

The plurality of longitudinally extending channels may comprise at least 5 longitudinally extending channels, at least 10 longitudinally extending channels, at least 20 longitudinally extending channels, or at least 30 longitudinally extending channels. That is, the convoluted sheet may define at least 5 longitudinally extending channels in the inner region, at least 10 longitudinally extending channels in the inner region, at least 20 longitudinally extending channels in the inner region, or at least 30 longitudinally extending channels in the inner region.

The plurality of longitudinally extending channels may have a maximum width of less than or equal to about 5 millimetres. That is, any one of the plurality of longitudinally extending channels may not have a width greater than about 5 millimetres.

The plurality of longitudinally extending channels may have a maximum width of less than or equal to about 4 millimetres, or less than or equal to about 3 millimetres.

The plurality of longitudinally extending channels may have a maximum cross-sectional area of less than or equal to about 4 square millimetres. That is, any one of the plurality of longitudinally extending channels may not have a cross-sectional area of greater than 4 square millimetres.

The plurality of longitudinally extending channels may have a maximum cross-sectional area of less than or equal to about 3 square millimetres, or less than or equal to about 2 millimetre squared.

The plurality of longitudinally extending channels may have an average width of less than or equal to about 4 millimetres, less than or equal to about 3 millimetres, or less than or equal to about 2 millimetres.

As used herein with reference to the invention, the average width of the plurality of longitudinally extending channels is the mean of the width of each of the longitudinally extending channels.

The plurality of longitudinally extending channels may have an average cross-sectional area of less than or equal to about 3 millimetres, less than or equal to about 2 millimetres, or less than or equal to about 1 square millimetres. As used herein with reference to the invention, the average cross-sectional area of the plurality of longitudinally extending channels is the mean of the cross-sectional area of each of the longitudinally extending channels.

The ratio of the maximum width of the plurality of longitudinally extending channels to the length of the convoluted sheet may be less than or equal to about 1 , less than or equal to about 0.8, or less than or equal to about 0.6.

The ratio of the maximum cross-sectional area of the plurality of longitudinally extending channels to the length of the convoluted sheet may be less than or equal to about 0.8, less than or equal to about 0.6, or less than or equal to about 0.4.

The ratio of the average width of the plurality of longitudinally extending channels to the length of the convoluted sheet may be less than or equal to about 0.8, less than or equal to about 0.6, or less than or equal to about 0.4.

The ratio of the average cross-sectional area of the plurality of longitudinally extending channels to the length of the convoluted sheet may be less than or equal to about 0.6, less than or equal to about 0.4, or less than or equal to about 0.2.

Preferably, the total cross-sectional area of the plurality of channels is substantially constant along the entire length of the convoluted sheet. For example, the cross-sectional area of each of the plurality of longitudinally extending channels may be substantially constant along the entire length of the convoluted sheet.

The tubular portion defines an inner region of the upstream element. The convoluted sheet is located in the inner region. The convoluted sheet defines a plurality of longitudinally extending channels in the inner region.

The total weight of the upstream element may be substantially the same as the combined weight of the tubular portion and the convoluted sheet.

The upstream element may consist of the tubular portion and the convoluted sheet.

Preferably, the tubular portion has sufficient rigidity so that the tubular portion does not collapse during storage, transportation and use of the aerosol-generating article. Collapse of the tubular portion may result in a change in one or both of the shape and size of one or more of the longitudinally extending channels. For example, collapse of the tubular portion may result in a change in one or both of the shape and size of one or more of the longitudinally extending channels adjacent to the tubular portion and defined by the convoluted sheet and the tubular portion. This may increase the resistance to draw of the upstream element. This may also adversely affect the ability of the upstream element to prevent or restrict upstream movement of aerosol-generating material from the aerosol-generating substrate.

The tubular portion may have a thickness of at least about 20 micrometres, at least about 40 micrometres, or at least about 60 micrometres. The tubular portion may have a thickness of less than or equal to about 140 micrometres, less than or equal to about 120 micrometres, or less than or equal to about 100 micrometres.

The tubular portion may have a thickness of between about 20 micrometres and about 140 micrometres, between about 20 micrometres and about 120 micrometres, or between about 20 micrometres and about 100 micrometres.

The tubular portion may have a thickness of between about 40 micrometres and about 140 micrometres, between about 40 micrometres and about 120 micrometres, or between about 40 micrometres and about 100 micrometres.

The tubular portion may have a thickness of between about 60 micrometres and about 140 micrometres, between about 60 micrometres and about 120 micrometres, or between about 60 micrometres and about 100 micrometres.

The thickness of the tubular portion may be selected based on a desired rigidity of the tubular portion.

The tubular portion may be formed by a wrapper that circumscribes the convoluted sheet.

Where the tubular portion is formed by a wrapper, the thickness of the tubular portion may be the same as the thickness of the wrapper.

The wrapper may have a basis weight of at least about 10 grams per square metre, at least about 15 grams per square metre, or at least about 20 grams per square metre.

The wrapper may have a basis weight of less than or equal to about 100 grams per square metre, less than or equal to about 80 grams per square metre, or less than or equal to about 60 grams per square metre.

The wrapper may have a basis weight of between about 10 grams per square metre and about 100 grams per square metre, between about 10 grams per square metre and about 80 grams per square metre, or between about 10 grams per square metre and about 60 grams per square metre.

The wrapper may have a basis weight of between about 15 grams per square metre and about 100 grams per square metre, between about 15 grams per square metre and about 80 grams per square metre, or between about 15 grams per square metre and about 60 grams per square metre.

The wrapper may have a basis weight of between about 20 grams per square metre and about 100 grams per square metre, between about 20 grams per square metre and about 80 grams per square metre, or between about 20 grams per square metre and about 60 grams per square metre.

The basis weight of the wrapper may be selected based on a desired rigidity of the upstream element.

The wrapper may be a paper wrapper.

The length of the tubular portion may be the same as the length of the upstream element. The width of the tubular portion may be the same as the width of the upstream element.

Unless otherwise stated, the resistance to draw (RTD) of the aerosol-generating article or a component of the aerosol-generating article is measured in accordance with ISO 6565-2015 at a volumetric flow rate of about 17.5 millilitres per second at the proximal end or downstream end of the aerosol-generating article or the component thereof at a temperature of about 22 degrees Celsius, a pressure of about 101 kPa (about 760 Torr) and a relative humidity of about 60%.

The RTD of the upstream element per unit length may be at least about 0.2 millimetres H2O per millimetre, at least about 0.5 millimetres H2O per millimetre, or at least about 1 millimetre H2O per millimetre.

The RTD of the upstream element per unit length may be less than or equal to about 3 millimetres H2O per millimetre, less than or equal to about 2.5 millimetres H2O per millimetre, or less than or equal to about 2 millimetres H2O per millimetre.

The RTD of the upstream element may be between about 0.2 millimetres H2O per millimetre and about 3 millimetres H2O per millimetre, between about 0.2 millimetres H2O per millimetre and about 2.5 millimetres H2O per millimetre, or between about 0.2 millimetres H2O per millimetre and about 2 millimetres H2O per millimetre.

The RTD of the upstream element may be between about 0.5 millimetres H2O per millimetre and about 3 millimetres H2O per millimetre, between about 0.5 millimetres H2O per millimetre and about 2.5 millimetres H2O per millimetre, or between about 0.5 millimetre H2O per millimetre and about 2 millimetres H2O per millimetre.

The RTD of the upstream element may be between about 1 millimetre H2O per millimetre and about 3 millimetres H2O per millimetre, between about 1 millimetre H2O per millimetre and about 2.5 millimetres H2O per millimetre, or between about 1 millimetre H2O per millimetre and about 2 millimetres H2O per millimetre.

For example, the RTD of the upstream element may be about 1.5 millimetres H2O per millimetre length of the upstream element.

The RTD of the upstream element may be at least about 1 millimetre H2O, at least 2.5 millimetres H2O, or at least 5 millimetres H2O.

The RTD of the upstream element may be less than or equal to about 15 millimetre H2O, less than or equal to about 12.5 millimetres H2O, or less than or equal to about 10 millimetres H ₂ O.

The RTD of the upstream element may be between about 1 millimetre H2O and about 15 millimetres H2O, between about 1 millimetre H2O and about 12.5 millimetres H2O, or between about 1 millimetre H2O and about 10 millimetres H2O.

The RTD of the upstream element may be between about 2.5 millimetres H2O and about 15 millimetres H2O, between about 2.5 millimetres H2O and about 12.5 millimetres H2O, or between about 2.5 millimetres H2O and about 10 millimetres H2O. The RTD of the upstream element may be between about 5 millimetres H2O and about 15 millimetres H2O, between about 5 millimetres H2O and about 12.5 millimetres H2O, or between about 5 millimetres H2O and about 10 millimetres H2O.

For example, the RTD of the upstream element may be about 7.5 millimetres H2O.

The RTD of the upstream element may be less than the RTD of the aerosol-generating substrate.

The upstream element may provide less than 50 percent of the overall RTD of the aerosolgenerating article. That is, the ratio of the RTD of the upstream element to the overall RTD of the aerosol-generating article may be less than 0.5.

The ratio of the RTD of the upstream element to the overall RTD of the aerosol-generating article may be less than or equal to about 0.4, less than or equal to about 0.3, or less than or equal to about 0.25.

The ratio of the RTD of the upstream element to the overall RTD of the aerosol-generating article may be at least about 0.01 , at least about 0.03, or at least about 0.05.

The upstream element may have a porosity of at least about 40 percent, at least about 45 percent, or at least about 50 percent.

The upstream element may have a porosity of less than or equal to about 85 percent, less than or equal to about 80 percent, or less than or equal to about 75 percent.

As used herein with reference to the invention, the porosity of the upstream element is defined by the ratio of the sum of the cross-sectional areas of components in the inner region of the upstream element to the cross-sectional area of the inner region. In an upstream element having a higher porosity, a smaller proportion of the cross-sectional area of the inner region is occupied by components in the inner region, and a larger proportion of the cross-sectional area of the inner region is empty space. In as upstream element having a lower porosity, a larger proportion of the cross-sectional area of the inner region is occupied by components in the inner region, and a smaller proportion of the cross-sectional area of the inner region is empty space.

Where the upstream element consists of the tubular portion and the convoluted sheet, the porosity of the upstream element is defined by the ratio of the cross-sectional area of the convoluted sheet to the cross-sectional area of the inner region expressed as a percentage.

Where the tubular portion defines an inner region of substantially circular cross-section, the cross-sectional area of the inner region is defined by the internal diameter of the tubular portion. For example, where the convoluted sheet has a cross-sectional area of 15 square millimetres and the internal diameter of the tubular portion is 7 millimetres, the porosity of the upstream element is about 61%.

The upstream element may have a density less than a density of the aerosol-generating substrate. As used herein with reference to the invention, the density of the upstream element refers to the bulk density of the upstream element. The bulk density of the upstream element is the total weight of the upstream element divided by the volume of the upstream element. For example, where the upstream element is substantially cylindrical and has a total weight of about 30 milligrams, a length of about 5 millimetres, and an external diameter of about 7.1 millimetres, the upstream element has a bulk density of about 150 milligrams per cubic centimetre.

The aerosol-generating article may have a hardness at the upstream element of at least about 80 percent, at least about 85 percent, or at least about 90 percent. This may advantageously help to reduce or avoid deformation of the upstream element during storage, transportation and use of the aerosol-generating article.

As used herein with reference to the invention, the term “hardness” is used to describe the resistance to deformation of the aerosol-generating article in the transverse direction. Hardness is generally expressed as a percentage. The hardness of the aerosol-generating article may be determined by measuring the width of the aerosol-generating article before applying a set load to the aerosol-generating article in the transverse direction, and measuring the depressed width of the aerosol-generating article after applying the set load for a set duration (but with the load still applied). The hardness is given by:

Hardness 100 % where Ws is the original (undepressed) width, and Wd is the depressed width after applying a set load for a set duration. The harder the material, the closer the hardness is to 100 percent.

To determine the hardness of a portion of an aerosol-generating article (such as an upstream element), aerosol-generating articles should be aligned parallel in a plane and the same portion of each aerosol-generating article to be tested should be subjected to a set load for a set duration. This test is performed using a known DD60A Densimeter device (manufactured and made commercially available by Heinr Borgwaldt GmbH, Germany), which is fitted with a measuring head for aerosol-generating articles and with an aerosol-generating article receptacle.

The load is applied using two load-applying cylindrical rods, which extend across the width of all of the aerosol-generating articles at once. According to the standard test method for this instrument, the test should be performed such that twenty contact points occur between the aerosol-generating articles and the load applying cylindrical rods. In some cases, the upstream element to be tested may be long enough such that only ten aerosol-generating articles are needed to form twenty contact points, with each aerosol-generating article contacting both load applying rods (because they are long enough to extend between the rods). In other cases, if the upstream elements are too short to achieve this, then twenty aerosol-generating articles should be used to form the twenty contact points, with each aerosol-generating article contacting only one of the load applying rods, as further discussed below. Two further stationary cylindrical rods are located underneath the aerosol-generating articles, to support the aerosol-generating articles and counteract the load applied by each of the load applying cylindrical rods.

For the standard operating procedure for such an apparatus, an overall load of 2 kg is applied for a duration of 20 seconds. After 20 seconds have elapsed (and with the load still being applied to the aerosol-generating articles), the depression in the load applying cylindrical rods is determined, and then used to calculate the hardness from the above equation. The temperature is kept in the region of 22 degrees Celsius ± 2 degrees. The test described above is referred to as the DD60A Test. The standard way to measure the hardness of the aerosol-generating article is prior to use of the aerosol-generating article. Additional information regarding measurement of average radial hardness can be found in, for example, US 2016/0128378 A1.

The upstream element may have a length of at least about 2 millimetres, at least about 3 millimetres, or at least about 4 millimetres.

The upstream element may have a length of less than or equal to about 10 millimetres, less than or equal to about 8 millimetres, or less than or equal to about 6 millimetres.

The upstream element may have a length of between about 2 millimetres and about 10 millimetres, between about 2 millimetres and about 8 millimetres, or between about

2 millimetres and about 6 millimetres.

The upstream element may have a length of between about 3 millimetres and about 10 millimetres, between about 3 millimetres and about 8 millimetres, or between about

3 millimetres and about 6 millimetres.

The upstream element may have a length of between about 4 millimetres and about 10 millimetres, between about 4 millimetres and about 8 millimetres, or between about

4 millimetres and about 6 millimetres.

For example, the upstream element may have a length of about 5 millimetres.

The length of the upstream element may be selected based on a desired balance between the ability of the upstream element to prevent or restrict upstream movement of aerosolgenerating material from the aerosol-generating substrate and the RTD of the upstream element.

The length of the upstream element may be selected based on a desired total length of the aerosol-generating article.

The ratio of the length of the upstream element to the total length of the aerosol-generating article may be at least about 0.03, at least about 0.05, or at least about 0.07.

The ratio of the length of the upstream element to the total length of the aerosol-generating article may be less than or equal to about 0.25, less than or equal to about 0.2, or less than or equal to about 0.15.

Preferably, the upstream element has a substantially circular cross-section. The upstream element may have an external diameter of at least about 5 millimetres, about 6 millimetres, or about 7 millimetres.

The upstream element may have an external diameter of less than or equal to 12 millimetres, less than or equal to about 10 millimetres, or less than or equal to about 8 millimetres.

The upstream element may have an external diameter of between about 5 millimetres and about 12 millimetres, between about 5 millimetres and about 10 millimetres, or between about

5 millimetres and about 8 millimetres.

The upstream element may have an external diameter of between about 6 millimetres and about 12 millimetres, between about 6 millimetres and about 10 millimetres, or between about

6 millimetres and about 8 millimetres.

The upstream element may have an external diameter of between about 7 millimetres and about 12 millimetres, between about 7 millimetres and about 10 millimetres, or between about

7 millimetres and about 8 millimetres.

For example, the upstream element may have an external diameter of about 7.1 millimetres.

Preferably, the external diameter of the upstream element is substantially the same as the external diameter of the aerosol-generating substrate.

Preferably, the external diameter of the upstream element is substantially the same as the external diameter of the aerosol-generating article.

The upstream element is upstream of the aerosol-generating substrate.

Preferably, the upstream element abuts the aerosol-generating substrate. This may advantageously improve the ability of the upstream element to prevent or restrict upstream movement of aerosol-generating material from the aerosol-generating substrate.

The upstream element may be at the upstream end of the aerosol-generating article.

The aerosol-generating article may comprise an additional element upstream of the upstream element. For example, the aerosol-generating article may comprise a plug of cellulose acetate tow upstream of the upstream element. An additional element upstream of the upstream element may act as a cap or cover to help avoid damage to the upstream element.

The upstream element may comprise less than or equal to about 1 percent by weight of aerosol former on a dry weight basis of the upstream element, less than or equal to about 0.5 percent by weight of aerosol former on a dry weight basis of the upstream element, or less than or equal to about 0.2 percent by weight of aerosol former on a dry weight basis of the upstream element.

The upstream element may be substantially free of aerosol former. The upstream element may be free of aerosol former. That is, the upstream element may comprise about 0 percent by weight of aerosol former on a dry weight basis of the upstream element. As discussed further below, the aerosol-generating substrate preferably comprises an aerosol former. Preferably, the ratio of the weight of aerosol former in the upstream element on a dry weight basis of the upstream element to the weight of aerosol former in the aerosolgenerating substrate based on a dry weight basis of the upstream element is less than or equal to about 0.2, less than or equal to about 0.1 , or less than or equal to about 0.05.

Preferably, the majority of aerosol generated by the aerosol-generating article is generated by the aerosol-generating substrate. The entirety of aerosol generated by the aerosolgenerating article may be generated by the aerosol-generating substrate.

The aerosol-generating substrate may be in the form of a rod.

As used herein with reference to the invention, the term “rod” is used to denote a generally cylindrical element having a substantially circular, oval or elliptical cross-section.

The aerosol-generating substrate may comprise aerosol-generating material circumscribed by a wrapper, such as a plug wrap. For example, the aerosol-generating substrate may comprise aerosol-generating material circumscribed by a wrapper to form a rod.

The aerosol-generating substrate may have a length of at least about 8 millimetres, at least about 9 millimetres, or at least about 10 millimetres.

The aerosol-generating substrate may have a length of less than or equal to about 16 millimetres, less than or equal to about 15 millimetres, or less than or equal to about 14 millimetres.

The aerosol-generating substrate may have a length of between about 8 millimetres and about 16 millimetres, between about 8 millimetres and about 15 millimetres, or between about

8 millimetres and about 14 millimetres.

The aerosol-generating substrate may have a length of between about 9 millimetres and about 16 millimetres, between about 9 millimetres and about 15 millimetres, or between about

9 millimetres and about 14 millimetres.

The aerosol-generating substrate may have a length of between about 10 millimetres and about 16 millimetres, between about 10 millimetres and about 15 millimetres, or between about

10 millimetres and about 14 millimetres.

For example, the aerosol-generating substrate may have a length of about 12 millimetres.

The ratio between the length of the aerosol-generating substrate to the total length of the aerosol-generating article may be at least about 0.10, at least about 0.15, or at least about 0.20.

The ratio between the length of the aerosol-generating substrate to the total length of the aerosol-generating article may be less than or equal to about 0.40, less than or equal to about 0.35, or less than or equal to about 0.3.

The ratio between the length of the aerosol-generating substrate to the total length of the aerosol-generating article may be between about 0.10 and about 0.40, between about 0.10 and about 0.35, or between about 0.10 and about 0.30. The ratio between the length of the aerosol-generating substrate to the total length of the aerosol-generating article may be between about 0.15 and about 0.40, between about 0.15 and about 0.35, or between about 0.15 and about 0.30.

The ratio between the length of the aerosol-generating substrate to the total length of the aerosol-generating article may be between about 0.20 and about 0.40, between about 0.20 and about 0.35, or between about 0.20 and about 0.30.

Preferably, the aerosol-generating substrate has a substantially circular cross-section.

The aerosol-generating substrate may have an external diameter of at least about 5 millimetres, about 6 millimetres, or about 7 millimetres.

The aerosol-generating substrate may have an external diameter of less than or equal to 12 millimetres, less than or equal to about 10 millimetres, or less than or equal to about 8 millimetres.

The aerosol-generating substrate may have an external diameter of between about

5 millimetres and about 12 millimetres, between about 5 millimetres and about 10 millimetres, or between about 5 millimetres and about 8 millimetres.

The aerosol-generating substrate may have an external diameter of between about

6 millimetres and about 12 millimetres, between about 6 millimetres and about 10 millimetres, or between about 6 millimetres and about 8 millimetres.

The aerosol-generating substrate may have an external diameter of between about

7 millimetres and about 12 millimetres, between about 7 millimetres and about 10 millimetres, or between about 7 millimetres and about 8 millimetres.

For example, the aerosol-generating substrate may have an external diameter of about 7.1 millimetres.

The aerosol-generating substrate may have a density of at least about 150 milligrams per cubic centimetre, at least about 175 milligrams per cubic centimetre, at least about 200 milligrams per cubic centimetre, or at least about 250 milligrams per cubic centimetre.

The aerosol-generating substrate may have a density of less than or equal to about 500 milligrams per cubic centimetre, less than or equal to about 450 milligrams per cubic centimetre, less than or equal to about 400 milligrams per cubic centimetre, or less than or equal to about 350 milligrams per cubic centimetre.

The aerosol-generating substrate may have a density of between about 150 milligrams per cubic centimetre and about 500 milligrams per cubic centimetre, between about 150 milligrams per cubic centimetre and about 450 milligrams per cubic centimetre, between about 150 milligrams per cubic centimetre and about 400 milligrams per cubic centimetre, or between about 150 milligrams per cubic centimetre and about 350 milligrams per cubic centimetre. The aerosol-generating substrate may have a density of between about 175 milligrams per cubic centimetre and about 500 milligrams per cubic centimetre, between about 175 milligrams per cubic centimetre and about 450 milligrams per cubic centimetre, between about 175 milligrams per cubic centimetre and about 400 milligrams per cubic centimetre, or between about 175 milligrams per cubic centimetre and about 350 milligrams per cubic centimetre.

The aerosol-generating substrate may have a density of between about 200 milligrams per cubic centimetre and about 500 milligrams per cubic centimetre, between about 200 milligrams per cubic centimetre and about 450 milligrams per cubic centimetre, between about 200 milligrams per cubic centimetre and about 400 milligrams per cubic centimetre, or between about 200 milligrams per cubic centimetre and about 350 milligrams per cubic centimetre.

The aerosol-generating substrate may have a density of between about 250 milligrams per cubic centimetre and about 500 milligrams per cubic centimetre, between about 250 milligrams per cubic centimetre and about 450 milligrams per cubic centimetre, between about 250 milligrams per cubic centimetre and about 400 milligrams per cubic centimetre, or between about 250 milligrams per cubic centimetre and about 350 milligrams per cubic centimetre.

For example, the aerosol-generating substrate may have a density of about 300 milligrams per cubic centimetre.

The RTD of the aerosol-generating substrate may be at least about 4 millimetres H2O, at least about 5 millimetres H2O, or at least about 6 millimetres H2O.

The RTD of the aerosol-generating substrate may be less than or equal to about 10 millimetres H2O, less than or equal to about 9 millimetres H2O, or less than or equal to about 8 millimetres H2O.

The RTD of the aerosol-generating substrate may be between about 4 millimetres H2O and about 10 millimetres H2O, between about 4 millimetres H2O and about 9 millimetres H2O, or between about 4 millimetres H2O and about 8 millimetres H2O.

The RTD of the aerosol-generating substrate may be between about 5 millimetres H2O and about 10 millimetres H2O, between about 5 millimetres H2O and about 9 millimetres H2O, or between about 5 millimetres H2O and about 8 millimetres H2O.

The RTD of the aerosol-generating substrate may be between about 6 millimetres H2O and about 10 millimetres H2O, between about 6 millimetres H2O and about 9 millimetres H2O, or between about 6 millimetres H2O and about 8 millimetres H2O.

The aerosol-generating substrate may be a solid aerosol-generating substrate.

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

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

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

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

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

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

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

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

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

As used herein with reference to the invention, the term “homogenised tobacco material” is used to describe material formed by agglomerating particulate tobacco material. Shreds of homogenised tobacco material may be formed from a sheet of homogenised tobacco material, for example, by cutting or shredding. Shreds of homogenised tobacco material may be formed by other methods, for example, by extrusion.

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

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

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

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

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

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

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

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

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

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

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

The size of the aerosol-generating material of the aerosol-generating substrate, such as a plurality of shreds of tobacco material, may play a role in the distribution of heat inside the aerosol-generating substrate. Also, the size of the aerosol-generating material may play a role in the resistance to draw of the article. In addition, the size of the aerosol-generating material may affect the ability of the upstream element to prevent or restrict movement of the aerosolgenerating material into the longitudinally extending channels of the upstream element. The size of the aerosol-generating material may also affect the ability of the upstream element to prevent or restrict upstream movement of the aerosol-generating material along the longitudinally extending channels and out of the upstream element.

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

At least about 60 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 1 millimetre, at least about 70 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 1 millimetre, or at least about 80 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 1 millimetre.

Where the homogenised plant material is in the form of a plurality of pellets or granules, at least about 70 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 0.5 millimetres, at least about 80 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 0.5 millimetres, or at least about 90 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 0.5 millimetres.

For example, at least about 80 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 1 millimetre and at least about 90% by weight of the plurality of pellets or granules may have a largest dimension greater than about 0.5 millimetres.

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

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

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

As used herein 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-generating substrate. For example, if the aerosol-generating substrate is formed from two individual sheets of tobacco material, then the combined thickness is the sum of the thickness of the two individual sheets of tobacco material or the measured thickness of the two sheets of tobacco material where the two sheets of tobacco material are stacked in the aerosol-generating substrate. The one or more sheets of tobacco material may each individually have a thickness of less than or equal to about 600 micrometres, less than or equal to about 300 micrometres, or less than or equal to about 250 micrometres.

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

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

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

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

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

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

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

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

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

The upstream element may advantageously prevent or restrict upstream movement of the susceptor during storage, transportation and use of the aerosol-generating article.

The susceptor may be an elongate susceptor.

As used herein with reference to the invention, the term “elongate” is used to describe a component of the aerosol-generating article having a length greater than the width and thickness thereof. The elongate susceptor may be arranged substantially longitudinally within the aerosolgenerating substrate. That is, the longitudinal axis of the elongate susceptor may be approximately parallel to the longitudinal axis of the aerosol-generating substrate. For example, the longitudinal axis of the elongate susceptor may be within plus or minus 10 degrees of parallel to the longitudinal axis of the aerosol-generating substrate. The elongate susceptor may be located in a radially central position within the aerosol-generating substrate, and extend along the longitudinal axis of the aerosol-generating substrate.

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

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

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

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

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

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

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

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

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

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

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

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

The susceptor may have a length of less than or equal to about 15 millimetres, less than or equal to about 12 millimetres, or less than or equal to about 10 millimetres.

The susceptor may have a length of between about 5 millimetres and about 15 millimetres, between about 5 millimetres and about 12 millimetres, or between about 5 millimetres and about 10 millimetres. The susceptor may have a length of between about 6 millimetres and about 15 millimetres, between about 6 millimetres and about 12 millimetres, or between about 6 millimetres and about 10 millimetres.

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

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

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

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

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

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

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

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

The susceptor may have a substantially circular cross-section.

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

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

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

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

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

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

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

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

The aerosol-generating article may comprise a mouthpiece element located downstream of the aerosol-generating substrate.

The mouthpiece element may be located at the downstream end or mouth end of the aerosol-generating article.

The mouthpiece element may be a mouthpiece filter element. The mouthpiece element may comprises at least one filter segment for filtering aerosol generated upon heating the aerosolgenerating substrate. For example, the mouthpiece element may comprise one or more segments of a fibrous filtration material. Suitable fibrous filtration materials are known in the art. For example, the at least one mouthpiece filter segment may comprise a cellulose acetate filter segment formed of cellulose acetate tow.

The mouthpiece element may consist of a single filter segment. The mouthpiece element may include two or more filter segments axially aligned in an abutting end to end relationship with each other.

The mouthpiece element may comprise a flavourant, which may be provided in any suitable form. For example, the mouthpiece element may comprise one or more capsules, beads or granules of a flavourant, or one or more flavour loaded threads or filaments.

Parameters or characteristics described herein in relation to the mouthpiece element as a whole may equally be applied to a filter segment of the mouthpiece element.

The mouthpiece element may have a low particulate filtration efficiency.

The mouthpiece element may have an RTD of less than or equal to about 25 millimetres H2O, less than or equal to about 20 millimetres H2O, or less than or equal to about 15 millimetres H ₂ O.

The mouthpiece element may have an RTD of at least about 10 millimetres H2O. The mouthpiece element may have an RTD of between about 10 millimetres H2O and about 25 millimetres H2O, between about 10 millimetres H2O and about 20 millimetres H2O, or between about 10 millimetres H2O and about 15 millimetres H2O.

Preferably, the mouthpiece element has a substantially circular cross-section.

Preferably, the mouthpiece element has an external diameter that is substantially the same as the external diameter of the aerosol-generating article.

The mouthpiece element may have a length of at least about 3 millimetres, or at least about 5 millimetres.

The length of the mouthpiece element may be less than or equal to about 11 millimetres, or less than or equal to about 9 millimetres.

The length of the mouthpiece element may be between about 3 millimetres and about 11 millimetres, or between about 3 millimetres and about 9 millimetres.

The length of the mouthpiece element may be between about 5 millimetres and about 11 millimetres, or between about 5 millimetres and about 9 millimetres.

For example, the length of the mouthpiece element may be about 7 millimetres.

The length of the mouthpiece element may be selected based on a desired total length of the aerosol-generating article.

The mouthpiece element may be circumscribed by a plug wrap.

The mouthpiece element may be unventilated such that air does not enter the aerosolgenerating article along the mouthpiece element.

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

The aerosol-generating article may comprise a mouth end cavity at the downstream end of the aerosol-generating article. The mouth end cavity may be downstream of the mouthpiece element, where present.

The mouth end cavity may be defined by a hollow tubular element provided at the downstream end of the mouthpiece. Alternatively, the mouth end cavity may be defined by an outer wrapper of the mouthpiece element, wherein the outer wrapper extends in a downstream direction from the mouthpiece element.

The aerosol-generating article may comprise one or more intermediate elements between the aerosol-generating substrate and the mouthpiece element. The one or more intermediate elements may be in an abutting end to end relationship with each other.

One of the one or more intermediate elements may abut the downstream end of the aerosol-generating substrate. One of the one or more intermediate elements may abut the upstream end of the mouthpiece element. For example, where there is a single intermediate element, the single intermediate element may abut both the downstream end of the aerosolgenerating substrate and the upstream end of the mouthpiece element. For example, where there are a plurality of intermediate elements, one intermediate element may abut the downstream end of the aerosol-generating substrate and another intermediate element may abut the upstream end of the mouthpiece element.

At least one of the one or more intermediate elements may be a hollow tubular element. The one or more intermediate elements may be one or more hollow tubular elements.

As used herein with reference to the invention, the term "hollow tubular element" is used to denote a generally cylindrical element having a lumen along a longitudinal axis thereof. The hollow tubular element may have a substantially circular, oval or elliptical cross-section. The lumen may have a substantially circular, oval or elliptical cross-section. In particular, the term "hollow tubular element" is used to denote an element defining at least one airflow conduit establishing an uninterrupted fluid communication between an upstream end of the hollow tubular element and a downstream end of the hollow tubular element.

In the context of the present invention, a hollow tubular element provides an unrestricted flow channel. This means that the hollow tubular element provides a negligible level of resistance to draw (RTD). As used herein with reference to the invention, the term “negligible level of RTD” is used to describe an RTD of less than 1 mm H2O per 10 millimetres of length of the hollow tubular element, less than 0.4 mm H2O per 10 millimetres of length of the hollow tubular element, or less than 0.1 mm H2O per 10 millimetres of length of the hollow tubular element. The flow channel should therefore be free from any components that would obstruct the flow of air in a longitudinal direction. Preferably, the flow channel is substantially empty.

The one or more intermediate elements may have a total length of at least about 10 millimetres, at least about 12 millimetres, or at least about 15 millimetres.

The one or more intermediate elements may have a total length of less than or equal to about 30 millimetres, less than or equal to about 25 millimetres, or less than or equal to about 23 millimetres.

The one or more intermediate elements may have a total length of between about 10 millimetres and about 30 millimetres, between about 10 millimetres and about 25 millimetres, or between about 10 millimetres and about 23 millimetres.

The one or more intermediate elements may have a total length of between about 12 millimetres and about 30 millimetres, between about 12 millimetres and about 25 millimetres, or between about 12 millimetres and about 23 millimetres.

The one or more intermediate elements may have a total length of between about 12 millimetres and about 30 millimetres, between about 12 millimetres and about 25 millimetres, or between about 12 millimetres and about 23 millimetres.

The total length of the one or more intermediate elements may be selected based on a desired total length of the aerosol-generating article. Where the aerosol-generating article comprises a single intermediate element, the total length of the one or more intermediate elements is the length of the single intermediate element. Where the aerosol-generating article comprises a plurality of intermediate elements, the total length of the one or more intermediate elements is the sum of the lengths of each of the plurality of intermediate elements.

Where the aerosol-generating article comprises a plurality of intermediate elements, the length of each of the plurality of intermediate elements may be substantially the same.

Preferably, each of the one or more intermediate elements has a substantially circular cross-section.

Preferably, the external diameter of each of the one or more intermediate elements is substantially the same as the external diameter of the aerosol-generating article.

The one or more intermediate elements may be formed from any suitable material or combination of materials. For example, at least one of the one or more intermediate elements may be formed from one or more materials selected from the group consisting of: cellulose acetate; a paper based material such as paper or cardboard; and polymeric materials, such as low density polyethylene (LDPE). Other suitable materials include polyhydroxyalkanoate (PHA) fibres.

A ventilation zone may be provided at a location along the one or more intermediate elements. A satisfactory cooling of the stream of aerosol generated upon heating the aerosolgenerating substrate and drawn through the one or more intermediate elements may be achieved by providing a ventilation zone at a location along the one or more intermediate elements. Without wishing to be bound by theory, the temperature drop caused by the admission of cooler, external air into the one or more intermediate elements via the ventilation zone may have an advantageous effect on the nucleation and growth of aerosol particles.

The ventilation zone may be provided at a location along at least one of the one or more intermediate elements.

Where the intermediate elements are hollow tubular elements, the ventilation zone may comprise a plurality of perforations through a tubular wall of at least one of the one or more hollow tubular elements. The ventilation zone may comprise at least one circumferential row of perforations. The ventilation zone may comprise two circumferential rows of perforations. For example, the perforations may be formed online during manufacturing of the aerosol-generating article. Each circumferential row of perforations may comprise from 8 to 30 perforations.

The aerosol-generating article may have a total length of at least about 35 millimetres, at least about 38 millimetres, at least about 40 millimetres, or at least about 42 millimetres.

The aerosol-generating article may have a total length of less than or equal to about 100 millimetres, less than or equal to about 70 millimetres, less than or equal to about 60 millimetres, or less than or equal to 50 millimetres. The aerosol-generating article may have a total length of between about 35 millimetres and about 100 millimetres, between about 35 millimetres and about 70 millimetres, between about 35 millimetres and about 60 millimetres, or between about 35 millimetres and about 50 millimetres.

The aerosol-generating article may have a total length of between about 38 millimetres and about 100 millimetres, between about 38 millimetres and about 70 millimetres, between about 38 millimetres and about 60 millimetres, or between about 38 millimetres and about 50 millimetres.

The aerosol-generating article may have a total length of between about 40 millimetres and about 100 millimetres, between about 40 millimetres and about 70 millimetres, between about 40 millimetres and about 60 millimetres, or between about 40 millimetres and about 50 millimetres.

The aerosol-generating article may have a total length of between about 42 millimetres and about 100 millimetres, between about 42 millimetres and about 70 millimetres, between about 42 millimetres and about 60 millimetres, or between about 42 millimetres and about 50 millimetres.

For example, the aerosol-generating article may have a total length of about 45 millimetres.

Preferably, the aerosol-generating article has a substantially circular cross-section.

The aerosol-generating article may have an external diameter of at least about 5 millimetres, at least about 6 millimetres, or at least about 7 millimetres.

The aerosol-generating article may have an external diameter of less than or equal to about 12 millimetres, less than or equal to about 10 millimetres, or less than or equal to about 8 millimetres.

The aerosol-generating article may have an external diameter of between about

5 millimetres and about 12 millimetres, between about 5 millimetres and about 10 millimetres, or between about 5 millimetres and about 8 millimetres.

The aerosol-generating article may have an external diameter of between about

6 millimetres and about 12 millimetres, between about 6 millimetres and about 10 millimetres, or between about 6 millimetres and about 8 millimetres.

The aerosol-generating article may have an external diameter of between about

7 millimetres and about 12 millimetres, between about 7 millimetres and about 10 millimetres, or between about 7 millimetres and about 8 millimetres.

For example, the aerosol-generating article may have an external diameter of about 7.1 millimetres.

According to a second aspect of the invention, there is provided an aerosol-generating system comprising: an aerosol-generating article according to the first aspect of the invention; and an aerosol-generating device configured to heat the aerosol-generating substrate of the aerosol-generating article, wherein the aerosol-generating device comprises a housing defining a cavity configured to receive the aerosol-generating article.

The aerosol-generating device may be a handheld aerosol-generating device.

The aerosol-generating device may be an electrically-operated aerosol-generating device.

The aerosol-generating device may comprise a power supply and control electronics.

The aerosol-generating device may comprise a battery and control electronics.

The aerosol-generating device may be configured to externally heat the aerosolgenerating substrate of the aerosol-generating article. That is, the aerosol-generating device may be configured to heat the aerosol-generating substrate of the aerosol-generating article from an exterior of the aerosol-generating substrate of the aerosol-generating article.

The aerosol-generating device may comprise a heating element, for example an external heating element.

The heating element may be located about a perimeter of the cavity.

The heating element may be one or both of a resistive heating element and an inductive heating element.

The aerosol-generating device may comprise a mouthpiece.

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, or embodiment, or aspect described herein.

EX1 : An aerosol-generating article comprising an aerosol-generating substrate and an upstream element provided upstream of the aerosol-generating substrate, wherein the upstream element comprises: a tubular portion defining an inner region of the upstream element, and a convoluted sheet defining a plurality of longitudinally extending channels in the inner region.

EX2: An aerosol-generating article according to EX1 , wherein the convoluted sheet comprises a plurality of non-concentric turns.

EX3: An aerosol-generating article according to EX1 or EX2, wherein the convoluted sheet has been one or more of crimped, folded, gathered, and pleated to define the plurality of longitudinally extending channels.

EX4: An aerosol-generating article according to any one of EX1 to EX3, wherein the convoluted sheet has been crimped.

EX5: An aerosol-generating article according to any one of EX1 to EX4, wherein the convoluted sheet has a plurality of substantially parallel ridges or corrugations extending in a longitudinal direction of the aerosol-generating article.

EX6: An aerosol-generating article according to EX5, wherein adjacent ridges or corrugations are spaced apart from each other by less than or equal to about 1.2 millimetres. EX7: An aerosol-generating article according to EX5 or EX6, wherein adjacent ridges or corrugations are spaced apart from each other by less than or equal to about 1 millimetre.

EX8: An aerosol-generating article according to any one of EX4 to EX7, wherein adjacent ridges or corrugations are spaced apart from each other by less than or equal to about 0.8 millimetres.

EX9: An aerosol-generating article according to any one of EX4 to EX8, wherein adjacent ridges or corrugations are spaced apart from each other by less than or equal to about 0.5 millimetres.

EX10: An aerosol-generating article according to any one of EX1 to EX9, wherein the convoluted sheet is a crimped and gathered sheet.

EX11 : An aerosol-generating article according to any one of EX1 to EX10, wherein the convoluted sheet extends from the downstream end of the upstream element towards the upstream end of the upstream element.

EX12: An aerosol-generating article according to any one of EX1 to EX11 , wherein the convoluted sheet extends from the upstream end of the upstream element towards the downstream end of the upstream element.

EX13: An aerosol-generating article according to any one of EX1 to EX12, wherein the length of the convoluted sheet is substantially the same as the length of the upstream element.

EX14: An aerosol-generating article according to any one of EX1 to EX13, wherein the plurality of longitudinally extending channels extend from the downstream end of the upstream element towards the upstream end of the upstream element.

EX15: An aerosol-generating article according to any one of EX1 to EX14, wherein the plurality of longitudinally extending channels extend from the upstream end of the upstream element towards the downstream end of the upstream element.

EX16: An aerosol-generating article according to any one of EX1 to EX15, wherein the convoluted sheet has a basis weight of less than or equal to about 100 grams per square metre.

EX17: An aerosol-generating article according to any one of EX1 to EX16, wherein the convoluted sheet has a basis weight of less than or equal to about 80 grams per square metre.

EX18: An aerosol-generating article according to any one of EX1 to EX17, wherein the convoluted sheet has a basis weight of less than or equal to about 70 grams per square metre.

EX19: An aerosol-generating article according to any one of EX1 to EX18, wherein the convoluted sheet has a basis weight of less than or equal to about 50 grams per square metre.

EX20: An aerosol-generating article according to any one of EX1 to EX19, wherein the convoluted sheet has a basis weight of at least about 10 grams per square metre.

EX21 : An aerosol-generating article according to any one of EX1 to EX20, wherein the convoluted sheet has a basis weight of at least about 15 grams per square metre. EX22: An aerosol-generating article according to any one of EX1 to EX21, wherein the convoluted sheet has a basis weight of at least about 20 grams per square metre.

EX23: An aerosol-generating article according to any one of EX1 to EX22, wherein the convoluted sheet has a weight of at least about 10 milligrams.

EX24: An aerosol-generating article according to any one of EX1 to EX23, wherein the convoluted sheet has a weight of at least about 15 milligrams.

EX25: An aerosol-generating article according to any one of EX1 to EX24, wherein the convoluted sheet has a weight of at least about 20 milligrams.

EX26: An aerosol-generating article according to any one of EX1 to EX25, wherein the convoluted sheet has a weight of less than or equal to about 100 milligrams.

EX27: An aerosol-generating article according to any one of EX1 to EX26, wherein the convoluted sheet has a weight of less than or equal to about 75 milligrams.

EX28: An aerosol-generating article according to any one of EX1 to EX27, wherein the convoluted sheet has a weight of less than or equal to about 50 milligrams.

EX29: An aerosol-generating article according to any one of EX1 to EX28, wherein the convoluted sheet has an average weight per unit length of less than or equal to about 20 milligrams per millimetre.

EX30: An aerosol-generating article according to any one of EX1 to EX29, wherein the convoluted sheet has an average weight per unit length of less than or equal to about 15 milligrams per millimetre.

EX31: An aerosol-generating article according to any one of EX1 to EX30, wherein the convoluted sheet has an average weight per unit length of less than or equal to about 10 milligrams per millimetre.

EX32: An aerosol-generating article according to any one of EX1 to EX31, wherein the convoluted sheet has an average weight per unit length of at least about 2 milligrams per millimetre.

EX33: An aerosol-generating article according to any one of EX1 to EX32, wherein the convoluted sheet has an average weight per unit length of at least about 3 milligrams per millimetre.

EX34: An aerosol-generating article according to any one of EX1 to EX33, wherein the convoluted sheet has an average weight per unit length of at least about 4 milligrams per millimetre.

EX35: An aerosol-generating article according to any one of EX1 to EX34, wherein the convoluted sheet has an average weight per unit volume of the inner region of less than or equal to about 500 micrograms per cubic millimetre. EX36: An aerosol-generating article according to any one of EX1 to EX35, wherein the convoluted sheet has an average weight per unit volume of the inner region of less than or equal to about 400 micrograms per cubic millimetre.

EX37: An aerosol-generating article according to any one of EX1 to EX36, wherein the convoluted sheet has an average weight per unit volume of the inner region of less than or equal to about 250 micrograms per cubic millimetre.

EX38: An aerosol-generating article according to any one of EX1 to EX37, wherein the convoluted sheet has an average weight per unit volume of the inner region of at least about 50 micrograms per cubic millimetre.

EX39: An aerosol-generating article according to any one of EX1 to EX38, wherein the convoluted sheet has an average weight per unit volume of the inner region of at least about 75 micrograms per cubic millimetre.

EX40: An aerosol-generating article according to any one of EX1 to EX39, wherein the convoluted sheet has an average weight per unit volume of the inner region of at least about 100 micrograms per cubic millimetre.

EX41 : An aerosol-generating article according to any one of EX1 to EX40, wherein the sheet has a thickness of less than or equal to about 300 micrometres.

EX42: An aerosol-generating article according to any one of EX1 to EX41 , wherein the sheet has a thickness of less than or equal to about 200 micrometres.

EX43: An aerosol-generating article according to any one of EX1 to EX42, wherein the sheet has a thickness of less than or equal to about 150 micrometres.

EX44: An aerosol-generating article according to any one of EX1 to EX43, wherein the sheet has a thickness of at least about 30 micrometres.

EX45: An aerosol-generating article according to any one of EX1 to EX45, wherein the sheet has a thickness of at least about 45 micrometres.

EX46: An aerosol-generating article according to any one of EX1 EX45, wherein the sheet has a thickness of at least about 60 micrometres.

EX47: An aerosol-generating article according to any one of EX1 to EX46, wherein the convoluted sheet has a cross-sectional area of at least about 5 square millimetres.

EX48: An aerosol-generating article according to any one of EX1 to EX47, wherein the convoluted sheet has a cross-sectional area of at least about 8 square millimetres.

EX49: An aerosol-generating article according to any one of EX1 to EX48, wherein the convoluted sheet has a cross-sectional area of at least about 10 square millimetres.

EX50: An aerosol-generating article according to any one of EX1 to EX49, wherein the convoluted sheet has a cross-sectional area of less than or equal to about 30 square millimetres.

EX51 : An aerosol-generating article according to any one of EX1 to EX50, wherein the convoluted sheet has a cross-sectional area of less than or equal to about 25 square millimetres. EX52: An aerosol-generating article according to any one of EX1 to EX51 , wherein the convoluted sheet has a cross-sectional area of less than or equal to about 20 square millimetres.

EX53: An aerosol-generating article according to any one of EX1 to EX52, wherein the cross-sectional area of the convoluted sheet is substantially constant along the length of the convoluted sheet.

EX54: An aerosol-generating article according to any one of EX1 to EX53, wherein the convoluted sheet has a surface area of at least about 250 square millimetres.

EX55: An aerosol-generating article according to any one of EX1 to EX54, wherein the convoluted sheet has a surface area of at least about 400 square millimetres.

EX56: An aerosol-generating article according to any one of EX1 to EX55, wherein the convoluted sheet has a surface area of at least about 600 square millimetres.

EX57: An aerosol-generating article according to any one of EX1 to EX56, wherein the convoluted sheet has a surface area of less than or equal to about 1500 square millimetres.

EX58: An aerosol-generating article according to any one of EX1 to EX57, wherein the convoluted sheet has a surface area of less than or equal to about 1350 square millimetres.

EX59: An aerosol-generating article according to any one of EX1 to EX58, wherein the convoluted sheet has a surface area of less than or equal to about 1250 square millimetres.

EX60: An aerosol-generating article according to any one of EX1 to EX59, wherein the convoluted sheet has an average surface area per unit length of at least about 50 square millimetres per millimetre.

EX61 : An aerosol-generating article according to any one of EX1 to EX60, wherein the convoluted sheet has an average surface area per unit length of at least about 80 square millimetres per millimetre.

EX62: An aerosol-generating article according to any one of EX1 to EX61 , wherein the convoluted sheet has an average surface area per unit length of at least about 120 square millimetres per millimetre.

EX63: An aerosol-generating article according to any one of EX1 to EX62, wherein the convoluted sheet has an average surface area per unit length of less than or equal to about 300 square millimetres per millimetre.

EX64: An aerosol-generating article according to any one of EX1 to EX63, wherein the convoluted sheet has an average surface area per unit length of less than or equal to about 270 square millimetres per millimetre.

EX65: An aerosol-generating article according to any one of EX1 to EX64, wherein the convoluted sheet has an average surface area per unit length of less than or equal to about 250 square millimetres per millimetre.

EX66: An aerosol-generating article according to any one of EX1 to EX65, wherein the convoluted sheet has a length of at least about 2 millimetres. EX67: An aerosol-generating article according to any one of EX1 to EX66, wherein the convoluted sheet has a length of at least about 3 millimetres.

EX68: An aerosol-generating article according to any one of EX1 to EX67, wherein the convoluted sheet has a length of at least about 4 millimetres.

EX69: An aerosol-generating article according to any one of EX1 to EX68, wherein the convoluted sheet has a length of less than or equal to about 10 millimetres.

EX70: An aerosol-generating article according to any one of EX1 to EX69, wherein the convoluted sheet has a length of less than or equal to about 8 millimetres.

EX71: An aerosol-generating article according to any one of EX1 to EX70, wherein the convoluted sheet has a length of less than or equal to about 6 millimetres,

EX72: An aerosol-generating article according to any one of EX1 to EX71, wherein the convoluted sheet has a length of about 5 millimetres.

EX73: An aerosol-generating article according to any one of EX1 to EX72, wherein the sheet has a width of at least about 50 millimetres.

EX74: An aerosol-generating article according to any one of EX1 to EX73, wherein the sheet has a width of at least about 80 millimetres.

EX75: An aerosol-generating article according to any one of EX1 to EX74, wherein the sheet has a width of at least about 120 millimetres.

EX76: An aerosol-generating article according to any one of EX1 to EX75, wherein the sheet has a width of less than or equal to about 300 millimetres.

EX77: An aerosol-generating article according to any one of EX1 to EX76, wherein the sheet has a width of less than or equal to about 270 millimetres.

EX78: An aerosol-generating article according to any one of EX1 to EX77, wherein the sheet has a width of less than or equal to about 250 millimetres.

EX79: An aerosol-generating article according to any one of EX1 to EX78, wherein the sheet has a linear shrinkage rate of less than or equal to about 4 percent.

EX80: An aerosol-generating article according to any one of EX1 to EX79, wherein the sheet has a linear shrinkage rate of less than or equal to about 3 percent.

EX81: An aerosol-generating article according to any one of EX1 to EX80, wherein the sheet has a linear shrinkage rate of less than or equal to about 2 percent.

EX82: An aerosol-generating article according to any one of EX1 to EX81, wherein the sheet has a linear shrinkage rate of less than or equal to about 1.5 percent.

EX83: An aerosol-generating article according to any one of EX1 to EX82, wherein the sheet has a linear shrinkage rate of less than or equal to about 1 percent.

EX84: An aerosol-generating article according to any one of EX1 to EX83, wherein the sheet has a linear shrinkage rate of less than or equal to about 0.5 percent. EX85: An aerosol-generating article according to any one of EX1 to EX84, wherein the sheet has an area shrinkage rate of less than or equal to about 8 percent.

EX86: An aerosol-generating article according to any one of EX1 to EX85, wherein the sheet has an area shrinkage rate of less than or equal to about 6 percent.

EX87: An aerosol-generating article according to any one of EX1 to EX86, wherein the sheet has an area shrinkage rate of less than or equal to about 3 percent.

EX88: An aerosol-generating article according to any one of EX1 to EX87, wherein the sheet has an area shrinkage rate of less than or equal to about 2 percent.

EX89: An aerosol-generating article according to any one of EX1 to EX88, wherein the sheet has an area shrinkage rate of less than or equal to about 1.5 percent.

EX90: An aerosol-generating article according to any one of EX1 to EX89, wherein the sheet has an area shrinkage rate of less than or equal to about 1 percent.

EX91 : An aerosol-generating article according to any one of EX1 to EX89, wherein the convoluted sheet is formed from a paper based material, such as paper or cardboard.

EX92: An aerosol-generating article according to any one of EX1 to EX88, wherein the convoluted sheet is formed from polylactic acid.

EX93: An aerosol-generating article according to any one of EX1 to EX92, wherein the convoluted sheet comprises a flame retardant coating.

EX94: An aerosol-generating article according to any one of EX1 to EX93, wherein the plurality of longitudinally extending channels are empty.

EX95: An aerosol-generating article according to any one of EX1 to EX94, wherein the plurality of longitudinally extending channels comprise at least 5 longitudinally extending channels.

EX96: An aerosol-generating article according to any one of EX1 to EX95, wherein the plurality of longitudinally extending channels comprise at least 10 longitudinally extending channels.

EX97: An aerosol-generating article according to any one of EX1 to EX96, wherein the plurality of longitudinally extending channels comprise at least 20 longitudinally extending channels.

EX98: An aerosol-generating article according to any one of EX1 to EX97, wherein the plurality of longitudinally extending channels comprise at least 30 longitudinally extending channels.

EX99: An aerosol-generating article according to any one of EX1 to EX98, wherein the plurality of longitudinally extending channels have a maximum width of less than or equal to about 5 millimetres. EX100: An aerosol-generating article according to any one of EX1 to EX99, wherein the plurality of longitudinally extending channels have a maximum width of less than or equal to about 4 millimetres.

EX101 : An aerosol-generating article according to any one of EX1 to EX100, wherein the plurality of longitudinally extending channels have a maximum width of less than or equal to about

3 millimetres.

EX102: An aerosol-generating article according to any one of EX1 to EX101 , wherein the plurality of longitudinally extending channels have a maximum cross-sectional area of less than or equal to about 4 square millimetres.

EX103: An aerosol-generating article according to any one of EX1 to EX102, wherein the plurality of longitudinally extending channels have a maximum cross-sectional area of less than or equal to about 3 square millimetres.

EX104: An aerosol-generating article according to any one of EX1 to EX103, wherein the plurality of longitudinally extending channels have a maximum cross-sectional area of less than or equal to about 2 square millimetres.

EX105: An aerosol-generating article according to any one of EX1 to EX104, wherein the plurality of longitudinally extending channels have an average width of less than or equal to about

4 millimetres.

EX106: An aerosol-generating article according to any one of EX1 to EX105, wherein the plurality of longitudinally extending channels have an average width of less than or equal to about 3 millimetres.

EX107: An aerosol-generating article according to any one of EX1 to EX106, wherein the plurality of longitudinally extending channels have an average width of less than or equal to about 2 millimetres.

EX108: An aerosol-generating article according to any one of EX1 to EX107, wherein the plurality of longitudinally extending channels have an average cross-sectional area of less than or equal to about 3 millimetres.

EX109: An aerosol-generating article according to any one of EX1 to EX108, wherein the plurality of longitudinally extending channels have an average cross-sectional area of less than or equal to about 2 millimetres.

EX110: An aerosol-generating article according to any one of EX1 to EX109, wherein the plurality of longitudinally extending channels have an average cross-sectional area of less than or equal to about 1 millimetre.

EX111 : An aerosol-generating article according to any one of EX1 to EX110, wherein the ratio of the maximum width of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 1 . EX112: An aerosol-generating article according to any one of EX1 to EX111 , wherein the ratio of the maximum width of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.8.

EX113: An aerosol-generating article according to any one of EX1 to EX112, wherein the ratio of the maximum width of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.6.

EX114: An aerosol-generating article according to any one of EX1 to EX113, wherein the ratio of the maximum cross-sectional area of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.8.

EX115: An aerosol-generating article according to any one of EX1 to EX114, wherein the ratio of the maximum cross-sectional area of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.6.

EX116: An aerosol-generating article according to any one of EX1 to EX115, wherein the ratio of the maximum cross-sectional area of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.4.

EX117: An aerosol-generating article according to any one of EX1 to EX116, wherein the ratio of the average width of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.8.

EX118: An aerosol-generating article according to any one of EX1 to EX117, wherein the ratio of the average width of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.6.

EX119: An aerosol-generating article according to any one of EX1 to EX118, wherein the ratio of the average width of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.4.

EX120: An aerosol-generating article according to any one of EX1 to EX119, wherein the ratio of the average cross-sectional area of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.6.

EX121 : An aerosol-generating article according to any one of EX1 to EX120, wherein the ratio of the average cross-sectional area of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.4.

EX122: An aerosol-generating article according to any one of EX1 to EX121 , wherein the ratio of the average cross-sectional area of the plurality of longitudinally extending channels to the length of the convoluted sheet is less than or equal to about 0.2.

EX123: An aerosol-generating article according to any one of EX1 to EX122, wherein the total cross-sectional area of the plurality of channels is substantially constant along the entire length of the convoluted sheet. EX124: An aerosol-generating article according to any one of EX1 to EX122, wherein the upstream element consists of the tubular portion and the convoluted sheet.

EX125: An aerosol-generating article according to any one of EX1 to EX124, wherein the tubular portion is formed by a wrapper that circumscribes the convoluted sheet.

EX126: An aerosol-generating article according to any one of EX1 to EX125, wherein the length of the tubular portion is the same as the length of the upstream element.

EX127: An aerosol-generating article according to any one of EX1 to EX126, wherein the RTD of the upstream element per unit length is at least about 0.2 millimetres H2O per millimetre.

EX128: An aerosol-generating article according to any one of EX1 to EX127, wherein the RTD of the upstream element per unit length is at least about 0.5 millimetres H2O per millimetre.

EX129: An aerosol-generating article according to any one of EX1 to EX128, wherein the RTD of the upstream element per unit length is at least about 2 millimetre H2O per millimetre.

EX130: An aerosol-generating article according to any one of EX1 to EX129, wherein the RTD of the upstream element per unit length is less than or equal to about 3 millimetres H2O per millimetre.

EX131 : An aerosol-generating article according to any one of EX1 to EX130, wherein the RTD of the upstream element per unit length is less than or equal to about 2.5 millimetres H2O per millimetre.

EX132: An aerosol-generating article according to any one of EX1 to EX131 , wherein the RTD of the upstream element per unit length is less than or equal to about 2 millimetres H2O per millimetre.

EX133: An aerosol-generating article according to any one of EX1 to EX132, wherein the RTD of the upstream element per unit length is about 1.5 millimetres H2O per millimetre.

EX134: An aerosol-generating article according to any one of EX1 to EX133, wherein the RTD of the upstream element is at least about 1 millimetre H2O.

EX135: An aerosol-generating article according to any one of EX1 to EX134, wherein the RTD of the upstream element is at least about 2.5 millimetres H2O.

EX136: An aerosol-generating article according to any one of EX1 to EX135, wherein the RTD of the upstream element is at least about 5 millimetres H2O.

EX137: An aerosol-generating article according to any one of EX1 to EX136, wherein the RTD of the upstream element is less than or equal to about 15 millimetres H2O.

EX138: An aerosol-generating article according to any one of EX1 to EX137, wherein the RTD of the upstream element is less than or equal to about 12.5 millimetres H2O.

EX139: An aerosol-generating article according to any one of EX1 to EX138, wherein the RTD of the upstream element is less than or equal to about 10 millimetres H2O.

EX140: An aerosol-generating article according to any one of EX1 to EX138, wherein the RTD of the upstream element is about 7.5 millimetres H2O. EX141 : An aerosol-generating article according to any one of EX1 to EX140, wherein the ratio of the RTD of the upstream element to the overall RTD of the aerosol-generating article is less than 0.5.

EX142: An aerosol-generating article according to any one of EX1 to EX141 , wherein the ratio of the RTD of the upstream element to the overall RTD of the aerosol-generating article is at least about 0.01.

EX143: An aerosol-generating article according to any one of EX1 to EX142, wherein the upstream element has a porosity of at least about 40 percent.

EX144: An aerosol-generating article according to any one of EX1 to EX143, wherein the upstream element has a porosity of at least about 45 percent.

EX145: An aerosol-generating article according to any one of EX1 to EX144, wherein the upstream element has a porosity of at least about 50 percent.

EX146: An aerosol-generating article according to any one of EX1 to EX145, wherein the upstream element has a porosity of less than or equal to about 85 percent.

EX147: An aerosol-generating article according to any one of EX1 to EX146, wherein the upstream element has a porosity of less than or equal to about 80 percent.

EX148: An aerosol-generating article according to any one of EX1 to EX147, wherein the upstream element has a porosity of less than or equal to about 75 percent.

EX149: An aerosol-generating article according to any one of EX1 to EX148, wherein the aerosol-generating article has a hardness at the upstream element of at least about 80 percent.

EX150: An aerosol-generating article according to any one of EX1 to EX149, wherein the upstream element has a length of at least about 2 millimetres.

EX152: An aerosol-generating article according to any one of EX1 to EX150, wherein the upstream element has a length of less than or equal to about 10 millimetres.

EX153: An aerosol-generating article according to any one of EX1 to EX152, wherein the ratio of the length of the upstream element to the total length of the aerosol-generating article is at least about 0.03.

EX154: An aerosol-generating article according to any one of EX1 to EX152, wherein the ratio of the length of the upstream element to the total length of the aerosol-generating article is less than or equal to about 0.25.

EX155: An aerosol-generating article according to any one of EX1 to EX154, wherein the external diameter of the upstream element is substantially the same as the external diameter of the aerosol-generating article.

EX155: An aerosol-generating article according to any one of EX1 to EX154, wherein the upstream element abuts the aerosol-generating substrate.

EX156: An aerosol-generating article according to any one of EX1 to EX155, wherein the upstream element is at the upstream end of the aerosol-generating article. EX157: An aerosol-generating article according to any one of EX1 to EX155, further comprising an additional element upstream of the upstream element.

EX158: An aerosol-generating article according to any one of EX1 to EX157, wherein the upstream element comprises less than or equal to about 1 percent by weight of aerosol former on a dry weight basis of the upstream element.

EX159: An aerosol-generating article according to any one of EX1 to EX157, wherein the upstream element is substantially free of aerosol former.

EX160: An aerosol-generating article according to any one of EX1 to EX159, wherein the ratio of the weight of aerosol former in the upstream element on a dry weight basis of the upstream element to the weight of aerosol former in the aerosol-generating substrate based on a dry weight basis of the upstream element is less than or equal to about 0.2.

EX161 : An aerosol-generating article according to any one of EX1 to EX160, wherein the aerosol-generating substrate has a density of at least about 150 milligrams per cubic centimetre.

EX162: An aerosol-generating article according to any one of EX1 to EX161 , wherein the aerosol-generating substrate has a density of at less than or equal to about 500 milligrams per cubic centimetre.

EX163: An aerosol-generating article according to any one of EX1 to EX162, wherein the aerosol-generating substrate comprises an aerosol former.

EX164: An aerosol-generating article according to any one of EX1 to EX163, wherein the aerosol-generating substrate comprises a plurality of shreds of tobacco material.

EX165: An aerosol-generating article according to any one of EX1 to EX164, wherein the aerosol-generating substrate comprises tobacco cut filler.

EX166: An aerosol-generating article according to any one of EX1 to EX165, wherein the aerosol-generating substrate comprises a plurality of shreds of homogenised tobacco material.

EX167: An aerosol-generating article according to any one of EX164 to EX166, wherein the shreds of tobacco material have a width of at least about 0.3 millimetres.

EX168: An aerosol-generating article according to any one of EX164 to EX167, wherein the shreds of tobacco material have a width of at least about 0.5 millimetres.

EX169: An aerosol-generating article according to any one of EX164 to EX168, wherein the shreds of tobacco material have a width of at least about 0.6 millimetres.

EX170: An aerosol-generating article according to any one of EX164 to EX169, wherein the shreds of tobacco material have a width of less than or equal to about 2 millimetres.

EX171 : An aerosol-generating article according to any one of EX164 to EX170, wherein the shreds of tobacco material have a width of less than or equal to about 1.2 millimetres.

EX172: An aerosol-generating article according to any one of EX164 to EX171 , wherein the shreds of tobacco material have a width of less than or equal to about 0.9 millimetres. EX173: An aerosol-generating article according to according to any one of EX164 to EX172, wherein the shreds of tobacco material have a length of at least about 10 millimetres.

EX174: An aerosol-generating article according to according to any one of EX164 to EX173, wherein the shreds of tobacco material have a length of less than or equal to about 40 millimetres.

EX175: An aerosol-generating article according to any one of EX1 to EX174, wherein the aerosol-generating substrate comprises a plurality of pellets or granules of tobacco material.

EX176: An aerosol-generating article according to EX175, wherein at least about 60 percent by weight of the plurality of pellets or granules have a largest dimension greater than about 1 millimetre.

EX177: An aerosol-generating article according to EX175 or EX176, wherein at least about 70 percent by weight of the plurality of pellets or granules have a largest dimension greater than about 1 millimetre.

EX178: An aerosol-generating article according to any one of EX175 to EX177, wherein at least about 80 percent by weight of the plurality of pellets or granules have a largest dimension greater than about 1 millimetre.

EX179: An aerosol-generating article according to any one of EX175 to EX178, wherein at least about 70 percent by weight of the plurality of pellets or granules have a largest dimension greater than about 0.5 millimetres.

EX180: An aerosol-generating article according to any one of EX175 to EX179, wherein at least about 80 percent by weight of the plurality of pellets or granules have a largest dimension greater than about 0.5 millimetres.

EX181 : An aerosol-generating article according to any one of EX175 to EX180, wherein at least about 90 percent by weight of the plurality of pellets or granules have a largest dimension greater than about 0.5 millimetres.

EX182: An aerosol-generating article according to any one of EX1 to EX181 , wherein the aerosol-generating substrate comprises one or more sheets of tobacco material.

EX183: An aerosol-generating article according to any one of EX1 to EX182, further comprising a susceptor arranged within the aerosol-generating substrate.

EX184: An aerosol-generating article according to any one of EX1 to EX183, further comprising a mouthpiece element located downstream of the aerosol-generating substrate.

EX185: An aerosol-generating article according to any one of EX1 to EX184, further comprising a mouth end cavity at the downstream end of the aerosol-generating article.

EX186: An aerosol-generating article according to EX184 or EX185, further comprising one or more intermediate elements between the aerosol-generating substrate and the mouthpiece element. EX187: An aerosol-generating article according to EX186, wherein at least one of the one or more intermediate elements is a hollow tubular element.

EX188: An aerosol-generating article according to any one of EX1 to EX187, wherein the weight of the upstream element is substantially the same as the combined weight of the tubular portion and the convoluted sheet.

EX189: An aerosol-generating article according to any one of EX1 to EX188, wherein the density of the upstream element is less than a density of the aerosol-generating substrate.

EX190: An aerosol-generating article according to any one of EX1 to EX189, wherein the RTD of the upstream element is less than the RTD of the aerosol-generating substrate.

EX191 : An aerosol-generating system comprising: an aerosol-generating article according to any one of EX1 to EX190 and an aerosol-generating device configured to heat the aerosolgenerating substrate of the aerosol-generating article, wherein the aerosol-generating device comprises a housing defining a cavity configured to receive the aerosol-generating article.

EX192: An aerosol-generating system according to EX191 , further comprising an external heating element.

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

Figure 1 shows a schematic side perspective view of an aerosol-generating article comprising an upstream element in accordance with an embodiment of the present invention; and Figure 2 shows a schematic side perspective view of the upstream element of the aerosolgenerating article shown in Figure 1.

Figure 1 shows an aerosol-generating article 10 having an upstream end 12 and a downstream end 14. The aerosol-generating article 10 comprises an aerosol-generating substrate 16 and an upstream element 18 located upstream of the aerosol-generating substrate 16. As shown in Figure 1 , a downstream end of the upstream element 18 abuts an upstream end of the aerosol-generating substrate 16. The aerosol-generating article 10 further comprises a hollow tubular element 20 located downstream of the aerosol-generating substrate 16, and a mouthpiece element 22 downstream of the hollow tubular element 20. The upstream end 12 of the aerosol-generating article 10 corresponds to the upstream end of the upstream element 18. The downstream end 14 of the aerosol-generating article 10 corresponds to a downstream end of the mouthpiece element 22.

The aerosol-generating article 10 has a total length of about 45 millimetres and an external diameter of about 7.1 millimetres.

The aerosol-generating substrate 16 comprises a plurality of shreds of tobacco material circumscribed by a plug wrap (not shown). The aerosol-generating substrate 16 comprises about 150 milligrams of tobacco material. The tobacco material comprises from about 13 percent by weight to about 16 percent by weight of glycerine. About 80 percent of the shreds of tobacco material have a width of greater than about 1 millimetre, and about 90 percent of the shreds of tobacco material have a width of greater than about 0.5 millimetres. The density of the aerosolgenerating substrate 16 is about 300 milligrams per cubic centimetre.

The hollow tubular element 20 is a hollow cylindrical tube made of cardboard. The hollow cylindrical tube defines an internal cavity that extends from an upstream end of the hollow tubular element 20 to a downstream end of the hollow tubular element 20. The internal cavity of the hollow tubular element 20 is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity of the hollow tubular element 20. The hollow tubular element 20 does not substantially contribute to the overall RTD of the aerosol-generating article 10.

The hollow tubular element 20 has a length of about 21 millimetres, an external diameter of about 7.1 millimetres, and an internal diameter of about 6.7 millimetres. Thus, a thickness of a tubular wall of the hollow tubular element 20 is about 0.2 millimetres.

The aerosol-generating article 10 comprises a ventilation zone at a location along the hollow tubular element. The ventilation zone comprises a circumferential row of perforations 24 extending through the tubular wall of the hollow tubular element 20, in order to allow air flow into the internal cavity of the hollow tubular element 20 from the exterior of the aerosol-generating article 10.

An upstream end of the mouthpiece element 22 abuts from a downstream end of the hollow tubular element 20. The mouthpiece element 22 has a length of about 7 mm and an external diameter of about 7.1 mm. The mouthpiece element 22 comprises a segment of low- density, cellulose acetate tow circumscribed by a plug wrap (not shown).

As shown in Figure 1 , the aerosol-generating article 10 comprises an upstream wrapper 26 circumscribing the upstream element 18, the aerosol-generating substrate 16 and the hollow tubular element 20. The ventilation zone comprises a circumferential row of perforations 28 extending through the upstream wrapper 26. The circumferential row of perforations 28 extending through the upstream wrapper 26 overlies the circumferential row of perforations 24 extending through the tubular wall of the hollow tubular element 20.

The aerosol-generating article 10 further comprises a downstream tipping wrapper 30 circumscribing the hollow tubular element 20 and the mouthpiece element 22. The tipping wrapper 30 overlies the portion of the upstream wrapper 26 that overlies the hollow tubular element 20. This way the tipping wrapper 30 effectively joins the mouthpiece element 22 to the other components of the aerosol-generating article 10. The ventilation zone may comprise a circumferential row of perforations (not shown) extending through the tipping wrapper 30. The circumferential row of perforations extending through the tipping wrapper 30 may overlie the circumferential row of perforations 28 extending through the upstream wrapper 26 and the circumferential row of perforations 24 extending through the tubular wall of the hollow tubular element 20. In Figure 1 , the upstream wrapper 26 and the downstream tipping wrapper 30 of the aerosol-generating article 10 are shown partially unwrapped in order to show the upstream element 18, the aerosol-generating substrate 16 and the hollow tubular element 20 of the aerosolgenerating article 10.

As shown in Figure 2, the upstream element 18 of the aerosol-generating article 10 comprises a tubular portion 32 defining an inner region of the upstream element 18, and a convoluted sheet 34 defining a plurality of longitudinally extending channels 36 in the inner region. The convoluted sheet 34 and the plurality of longitudinally extending channels 36 extend along the entire length of the upstream element 18.

The tubular portion 32 is formed from a paper wrapper that circumscribes the convoluted sheet 34. The paper wrapper forming the tubular portion 32 has a thickness of about 50 micrometres.

The convoluted sheet 34 has a basis weight of about 30 grams per square metre and a surface area of about 850 square millimetres.

The convoluted sheet 34 is a convoluted paper sheet. The paper sheet used to form the convoluted sheet 34 is rectangular in shape and has a width of about 170 millimetres and a length of about 5 millimetres.

The convoluted sheet 34 is a crimped and gathered sheet. The convoluted sheet 34 has a plurality of substantially parallel ridges 38 that extend substantially parallel to the longitudinal axis (shown using a dashed and dotted line in Figure 2) of the upstream element 18. Adjacent ridges 38 are separated by a distance of about 0.5 millimetres.

The upstream element 18 has a length of about 5 millimetres, an external diameter D of about 7.1 millimetres, and an internal diameter of about 7 millimetres.

The upstream element 18 is substantially free of aerosol former.

The specific embodiments and examples described above illustrate, but do not limit, the invention. It is to be understood that other embodiments of the invention may be made and the specific embodiments and examples described herein are not exhaustive.