WO2020089070A1

WO2020089070A1 - Smoking substitute consumable

Info

Publication number: WO2020089070A1
Application number: PCT/EP2019/079172
Authority: WO
Inventors: Kate FERRIE; Edward Ross SHENTON
Original assignee: Nerudia Ltd
Current assignee: Nerudia Ltd
Priority date: 2018-10-29
Filing date: 2019-10-25
Publication date: 2020-05-07
Anticipated expiration: 2021-04-29
Also published as: TW202027623A; GB201817564D0

Abstract

The present disclosure relates to a tow filter element, an aerosol-forming article e.g. a consumable for use in a smoking substitute system and particularly, although not exclusively, to a heat-not-burn (HNB) consumable, wherein the article/consumable comprises a tow filter element. The present disclosure also relates to a method of using the system. The tow filter element comprises a bore (8) extending longitudinally therethrough. At least a portion of the bore has a non-circular transverse cross-section.

Description

Smoking substitute consumable

Field of the Disclosure

The present disclosure relates to a consumable for use in a smoking substitute system and particularly, although not exclusively, to a heat-not-burn (HNB) consumable.

Background

The smoking of tobacco is generally considered to expose a smoker to potentially harmful substances. It is generally thought that a significant amount of the potentially harmful substances are generated through the heat caused by the burning and/or combustion of the tobacco and the constituents of the burnt tobacco in the tobacco smoke itself.

Conventional combustible smoking articles, such as cigarettes, typically comprise a cylindrical rod of tobacco comprising shreds of tobacco which is surrounded by a wrapper, and usually also a cylindrical filter axially aligned in an abutting relationship with the wrapped tobacco rod. The filter typically comprises a filtration material which is circumscribed by a plug wrap. The wrapped tobacco rod and the filter are joined together by a wrapped band of tipping paper that circumscribes the entire length of the filter and an adjacent portion of the wrapped tobacco rod. A conventional cigarette of this type is used by lighting the end opposite to the filter, and burning the tobacco rod. The smoker receives mainstream smoke into their mouth by drawing on the mouth end or filter end of the cigarette.

Combustion of organic material such as tobacco is known to produce tar and other potentially harmful byproducts. There have been proposed various smoking substitute systems (or“substitute smoking systems”) in order to avoid the smoking of tobacco.

Such smoking substitute systems can form part of nicotine replacement therapies aimed at people who wish to stop smoking and overcome a dependence on nicotine.

Smoking substitute systems include electronic systems that permit a user to simulate the act of smoking by producing an aerosol (also referred to as a“vapour”) that is drawn into the lungs through the mouth (inhaled) and then exhaled. The inhaled aerosol typically bears nicotine and/or flavourings without, or with fewer of, the odour and health risks associated with traditional smoking.

In general, smoking substitute systems are intended to provide a substitute for the rituals of smoking, whilst providing the user with a similar experience and satisfaction to those experienced with traditional smoking and with combustible tobacco products. Some smoking substitute systems use smoking substitute articles that are designed to resemble a traditional cigarette and are cylindrical in form with a mouthpiece at one end.

The popularity and use of smoking substitute systems has grown rapidly in the past few years. Although originally marketed as an aid to assist habitual smokers wishing to quit tobacco smoking, consumers are increasingly viewing smoking substitute systems as desirable lifestyle accessories.

There are a number of different categories of smoking substitute systems, each utilising a different smoking substitute approach.

One approach for a smoking substitute system is the so-called "heat not burn" (“HNB”) approach in which tobacco (rather than an“e-liquid”) is heated or warmed to release vapour. The tobacco may be leaf tobacco or reconstituted tobacco. The vapour may contain nicotine and/or flavourings. In the HNB approach the intention is that the tobacco is heated but not burned, i.e. the tobacco does not undergo combustion.

A typical HNB smoking substitute system may include a device and a consumable. The consumable may include the tobacco material. The device and consumable may be configured to be physically coupled together. In use, heat may be imparted to the tobacco material by a heating element of the device, wherein airflow through the tobacco material causes moisture in the tobacco material to be released as vapour. A vapour may also be formed from a carrier in the tobacco material (this carrier may for example include propylene glycol and/or vegetable glycerine) and additionally volatile compounds released from the tobacco. The released vapour may be entrained in the airflow drawn through the tobacco.

As the vapour passes through the consumable (entrained in the airflow) from an inlet to a mouthpiece (outlet), the vapour cools and condenses to form an aerosol for inhalation by the user. The aerosol will normally contain the volatile compounds.

In HNB smoking substitute systems, heating as opposed to burning the tobacco material is believed to cause fewer, or smaller quantities, of the more harmful compounds ordinarily produced during smoking. Consequently, the HNB approach may reduce the odour and/or health risks that can arise through the burning, combustion and pyrolytic degradation of tobacco.

In some cases, the aerosol passing from the mouthpiece (i.e. being inhaled by a user) may not be in a desirable state. Thus, it may be desirable to alter one or more characteristics of the aerosol before it is inhaled by the user.

There is a need for an improved design of HNB consumables to enhance the user experience and improve the function of the HNB smoking substitute system.

The present disclosure has been devised in the light of the above considerations. Summary of the Disclosure

At its most general, the present disclosure relates to an aerosol-forming article e.g. a smoking substitute article such as an HNB consumable comprising a filter having a non-circular bore.

According to a first aspect, there is provided a filter element for an aerosol-forming article, the filter element comprising a bundle of filter tows with a bore extending longitudinally therethrough, at least a portion of the bore having a non-circular transverse cross-section.

The presence of a bore in the filter element may act to mix volatile compounds (e.g. nicotine) with outer components (e.g. humectant) of a vapour/aerosol passing through the filter element. The bore may also result in a more reactive draw when used in a smoking substitute system (as discussed below). A noncircular transverse cross-section may result in the aerosol/vapour flowing through the bore having a different flow characteristic or flow pattern than if the cross-section of the bore were circular.

Optional features will now be set out. These are applicable singly or in any combination with any aspect.

The filter tows may be e.g. acetate tows or polypropylene tows.

In some embodiments, the bore in the filter element has a non-circular transverse cross-section along its entire axial length.

In some embodiments the transverse cross-section of the at least a portion of the bore may comprise a plurality of edges.

At least one of the plurality of edges may be substantially straight (e.g. linear). For example, the bore may have a square or rectangular or triangular, or pentagonal or hexagonal or octagonal etc. transverse cross- sectional profile.

In other embodiments, the edges may be curved. For example, the bore may have a heart-shaped transverse cross-sectional profile.

In some embodiments the transverse cross-section of the at least a portion of the bore may comprise a central portion and a plurality of lobes projecting outwardly from the central portion. The lobes may each comprise a generally linear form (e.g. formed of a plurality of straight edges), or may comprise a curved form (e.g. formed of one or more curved edges).

In some embodiments the shape of the transverse cross-section of the at least a portion of the bore may be one of a star shape, flower shape or asterisk shape (e.g. five-pointed or six-pointed). In some embodiments the cross-sectional area of the transverse cross-section of the bore may be substantially consistent/uniform for the entire axial length, or substantially the entire axial length, of the bore. Alternatively, the cross-sectional area of the transverse cross-section of the bore may vary along the length of the bore. For example, the bore may have a larger cross-section at a first axial (e.g. upstream) end than at an opposing second axial (e.g. downstream) end (and may gradually decrease from the first end to the second end).

In some embodiments the shape of the transverse cross-section of the bore may be substantially consistent/uniform for the entire axial length, or substantially the entire axial length, of the bore (i.e. such that the entire bore has a non-circular transverse cross-section). Alternatively, the shape of the cross- section of the bore may vary along the length of the bore. For example, the bore may have a square cross- section at a first end and a triangular cross-section at an opposing second end (and may gradually change from being a square to a triangle from the first end to the second end).

The bore may extend completely through the filter element. Alternatively, the bore may extend partway through the filter element. The bore may extend along a central longitudinal axis of the filter element or may be offset (i.e. in a radial direction) from the central longitudinal axis. The bore may extend at an angle to a longitudinal axis of the filter element. The bore may alternatively extend along a curved path (i.e. rather than a linear path along an axis).

The cross-sectional area of the at least a portion of the bore may be between 0.8 mm² and 20 mm², e.g. between 3 mm² and 12 mm² or between 3 mm² and 7 mm ².

In some embodiments the filter element may comprise a plurality of bores. Each of the plurality of bores may have a non-circular transverse cross-section. Each bore may be as described above. Each of the plurality of bores may comprise a transverse cross-section that is different to the transverse cross-section of one or more of the other bores. The non-circular cross-sections of the plurality of bores may have a total cross-sectional area of between 0.8 mm² and 20 mm², e.g. between 3 mm² and 12 mm² or between 3 mm² and 7 mm ².

The filter element may have a substantially cylindrical shape. The axial length of the filter element may be less than 20mm, e.g. between 8 and 15mm, for example between 9 and 13 mm e.g. between 10 and 12mm.

According to a second aspect there is provided an aerosol-forming article (e.g. a smoking substitute article such as an HNB consumable) comprising an aerosol-forming substrate, and a filter element according to the first aspect downstream of the aerosol-forming substrate.

As used herein, the terms’’upstream” and“downstream” are intended to refer to the flow direction of the vapour/aerosol i.e. with the downstream end of the article being the mouth end or outlet where the aerosol exits the article for inhalation by the user. The upstream end of the article is the opposing end to the downstream end.

In some embodiments the filter element may be a terminal filter element located at a downstream end of the aerosol-forming article. The or each bore may have a non-circular transverse cross-section at least at the downstream axial end of the terminal filter element.

In other embodiments the filter element may be an upstream filter element located proximate to the substrate.

In some embodiments the aerosol-forming article may be a heat-not-burn (HNB) consumable.

The aerosol-forming substrate is capable of being heated to release at least one volatile compound that can form an aerosol. The aerosol-forming substrate may be located at the upstream end of the article/consumable.

In order to generate an aerosol, the aerosol-forming substrate comprises at least one volatile compound that is intended to be vaporised/aerosolised and that may provide the user with a recreational and/or medicinal effect when inhaled. Suitable chemical and/or physiologically active volatile compounds include the group consisting of: nicotine, cocaine, caffeine, opiates and opoids, cathine and cathinone, kavalactones, mysticin, beta-carboline alkaloids, salvinorin A together with any combinations, functional equivalents to, and/or synthetic alternatives of the foregoing.

The aerosol-forming substrate may comprise plant material. The plant material may comprise least one plant material selected from the list including Amaranthus dubius, Arctostaphylos uva-ursi (Bearberry), Argemone mexicana, Arnica, Artemisia vulgaris, Yellow Tees, Galea zacatechichi, Canavalia maritima (Baybean), Cecropia mexicana (Guamura), Oestrum noctumum, Cynoglossum virginianum (wild comfrey), Cytisus scoparius, Damiana, Entada rheedii, Eschscholzia califomica (California Poppy), Fittonia albivenis, Hippobroma longi flora, Humulus japonica (Japanese Hops), Humulus lupulus (Hops), Lactuca virosa (Lettuce Opium), Laggera alata, Leonotis leonurus, Leonurus cardiaca (Motherwort), Leonurus sibiricus (Honeyweed), Lobelia cardinalis, Lobelia inflata (Indian-tobacco), Lobelia siphilitica, Nepeta cataria (Catnip), Nicotiana species (Tobacco), Nymphaea alba (White Lily), Nymphaea caerulea (Blue Lily), Opium poppy, Passiflora incamata (Passionflower), Pedicularis densiflora (Indian Warrior), Pedicularis groenlandica (Elephant's Head), Salvia divinorum, Salvia dorrii (Tobacco Sage), Salvia species (Sage), Scutellaria galericulata, Scutellaria lateriflora, Scutellaria nana, Scutellaria species (Skullcap), Sida acuta (Wireweed), Sida rhombi folia, Silene capensis, Syzygium aromaticum (Clove), Tagetes lucida (Mexican Tarragon), Tarchonanthus camphoratus, Tumera diffusa (Damiana), Verbascum (Mullein), Zamia latifolia (Maconha Brava) together with any combinations, functional equivalents to, and/or synthetic alternatives of the foregoing.

Preferably, the plant material is tobacco. Any type of tobacco may be used. This includes, but is not limited to, flue-cured tobacco, burley tobacco, Maryland Tobacco, dark-air cured tobacco, oriental tobacco, dark-fired tobacco, perique tobacco and rustica tobacco. This also includes blends of the above mentioned tobaccos.

Any suitable parts of the tobacco plant may be used. This includes leaves, stems, roots, bark, seeds and flowers.

The tobacco may comprise one or more of leaf tobacco, stem tobacco, tobacco powder, tobacco dust, tobacco derivatives, expanded tobacco, homogenised tobacco, shredded tobacco, extruded tobacco, cut rag tobacco and/or reconstituted tobacco (e.g. slurry recon or paper recon).

The aerosol-forming substrate may comprise a gathered sheet of homogenised (e.g. paper/slurry recon) tobacco or gathered shreds/strips formed from such a sheet.

In some embodiments, the sheet used to form the aerosol-forming substrate has a grammage greater than or equal to 100 g/m², e.g. greater than or equal to 1 10 g/m² such as greater than or equal to 120 g/m².

The sheet may have a grammage of less than or equal to 300 g/m² e.g. less than or equal to 250 g/m² or less than or equal to 200 g/m².

The sheet may have a grammage of between 120 and 190 g/m².

The aerosol-forming substrate may comprise at least 50 wt% plant material, e.g. at least 60 wt% plant material e.g. around 65 wt% plant material. The aerosol-forming substrate may comprise 80 wt% or less plant material e.g. 75 or 70 wt% or less plant material.

The aerosol-forming substrate may comprise one or more additives selected from humectants, flavourants, fillers, aqueous/non-aqueous solvents and binders.

Humectants are provided as vapour generators - the resulting vapour helps carry the volatile active compounds and increases visible vapour. Suitable humectants include polyhydric alcohols (e.g. propylene glycol (PG), triethylene glycol, 1 ,2-butane diol and vegetable glycerine (VG)) and their esters (e.g. glycerol mono-, di- or tri-acetate). They may be present in the aerosol-forming substrate in an amount between 1 and 50 wt%. The humectant content of the aerosol-forming substrate may have a lower limit of at least 1 % by weight of the plant material, such as at least 2 wt %, such as at least 5 wt %, such as at least 10 wt %, such as at least 20 wt %, such as at least 30 wt %, or such as least 40 wt %.

The humectant content of the aerosol-forming substrate may have an upper limit of at most 50 % by weight of the plant material, such as at most 40 wt %, such as at most 30 wt %, or such as at most 20 wt %.

Preferably, the humectant content is 1 to 40 wt % of the aerosol-forming substrate, such as 1 to 20 wt %

Suitable binders are known in the art and may act to bind together the components forming the aerosolforming substrate. Binders may comprise starches and/or cellulosic binders such as methyl cellulose, ethyl cellulose, hydroxy propyl cellulose, hydroxyethyl cellulose and methyl cellulose, gums such as xanthan, guar, arabic and/or locust bean gum, organic acids and their salts such as alginic acid/ sodium alginate, agar and pectins.

Preferably the binder content is 5 to 10 wt% of the aerosol-forming substrate e.g. around 6 to 8 wt%.

Suitable fillers are known in the art and may act to strengthen the aerosol-forming substrate. Fillers may comprise fibrous (non-tobacco) fillers such as cellulose fibres, lig nocellulose fibres (e.g. wood fibres), jute fibres and combinations thereof.

Preferably, the filler content is 5 to 10 wt% of the aerosol-forming substrate e.g. around 6 to 9 wt%.

The aerosol-forming substrate may comprise an aqueous and/or non-aqueous solvent. In some embodiments, the aerosol forming substrate has a water content of between 5 and 10 wt% e.g. between 6-9 wt% such as between 7-9 wt%.

The flavourant may be provided in solid or liquid form. It may include menthol, liquorice, chocolate, fruit flavour (including e.g. citrus, cherry etc.), vanilla, spice (e.g. ginger, cinnamon) and tobacco flavour. The flavourant may be evenly dispersed throughout the aerosol-forming substrate or may be provided in isolated locations and/or varying concentrations throughout the aerosol-forming substrate.

The aerosol-forming substrate may be formed in a substantially cylindrical shape such that the article/consumable resembles a conventional cigarette. It may have a diameter of between 5 and 10mm e.g. between 6 and 9mm or 6 and 8mm e.g. around 7 mm. It may have an axial length of between 10 and 15mm e.g. between 1 1 and 14mm such as around 12 or 13mm.

The aerosol-forming substrate may be circumscribed by a wrapping layer e.g. a paper wrapping layer. The wrapping layer may overlie an inner foil layer or may comprise a paper/foil laminate (with the foil innermost). The article/consumable may comprise one or more further filter elements in addition to the filter element described above (i.e. having one or more non-circular bores). Where the filter element is a terminal filter element, the further filter element may be an upstream filter element located between the substrate and the filter element (e.g. located adjacent or proximate to the substrate). Similarly, where the filter element is an upstream filter element, there may be a further filter element in the form of a terminal filter element located at a downstream end of the article.

The further filter element(s) (e.g. the upstream filter element) may be comprised of cellulose acetate or polypropylene tow. The at least one further filter element (e.g. the upstream filter element) may be comprised of activated charcoal. The at least one further filter element (e.g. the upstream filter element) may be comprised of paper. The at least one further filter element (e.g. the upstream filter element) may be comprised of extruded plant material. The or each filter element (i.e. including the filter element with the non-circular bore) may be circumscribed with a plug wrap e.g. a paper plug wrap.

The or each filter element may have a substantially cylindrical shape with a diameter substantially matching the diameter of the aerosol-forming substrate (with or without its associated wrapping layer). The axial length of the or each further filter element may be less than 20mm, e.g. between 8 and 15mm, for example between 9 and 13 mm e.g. between 10 and 12mm.

The or at least one of the further filter element(s) may be a solid filter element. The or at least one of the further filter element(s) may be a hollow bore filter element. The or each hollow bore filter element may have a bore diameter of between 1 and 5 mm, e.g. between 2 and 4 mm or between 2 and 3 mm.

There may be a plurality of e.g. two filter elements which may be adjacent one another or which may be spaced apart. Any filter element(s) upstream of the terminal filter element may be at least partly (e.g. entirely) circumscribed by the (paper) wrapping layer.

The terminal filter element (at the downstream end of the article/consumable) may be joined to the upstream elements forming the article/consumable by a circumscribing tipping layer e.g. a tipping paper layer. The tipping paper may have an axial length longer than the axial length of the terminal filter element such that the tipping paper completely circumscribes the terminal filter element plus the wrapping layer surrounding any adjacent upstream element.

The or at least one of the further filter elements may include a capsule e.g. a crushable capsule (crush-ball) containing a liquid flavourant e.g. any of the flavourants listed above. The capsule can be crushed by the user during smoking of the article/consumable to release the flavourant. The capsule may be located at the axial centre of the further filter element. In some embodiments, the article/consumable may comprise an aerosol-cooling element which is adapted to cool the aerosol generated from the aerosol-forming substrate (by heat exchange) before being inhaled by the user.

The aerosol-cooling element will be downstream from the aerosol-forming substrate. For example, it may be between the aerosol-forming substrate and the upstream filter element and/or between the two filter elements. The aerosol cooling element may be at least partly (e.g. completely) circumscribed by the (paper) wrapping layer.

The aerosol-cooling element may be formed of a plastics material selected from the group consisting of polylactic acid (PLA), polyvinyl chloride (PVC), polyethylene (PE) and polyethylene terephthalate (PET). The aerosol-cooling element may be formed of a crimped/gathered sheet of material to form a structure having a high surface area with a plurality of longitudinal bores to maximise heat exchange and cooling of the aerosol.

The article/consumable may comprise a spacer element that defines a space or cavity or chamber between the aerosol-forming substrate and the downstream end of the article/consumable. For example, it may be between the aerosol-forming substrate and the upstream filter element and/or between the two filter elements. The spacer acts to allow both cooling and mixing of the aerosol. The spacer element may comprise a cardboard tube. The spacer element may be at least partly (e.g. entirely) circumscribed by the (paper) wrapping layer.

The spacer element may have an external diameter of between 5 and 10mm e.g. between 6 and 9mm or 6 and 8mm e.g. around 7 mm. It may have an axial length of between 10 and 15mm e.g. between 12 and 14 mm or 13 and 14mm e.g. around 14mm.

In a third aspect, there is provided a system (e.g. a smoking substitute system) comprising an aerosolforming article according to the first aspect and a device comprising a heating element.

The device may be a HNB device i.e. a device adapted to heat but not combust the aerosol-forming substrate.

The device may comprise a main body for housing the heating element. The heating element may comprise an elongated e.g. rod, tube-shaped or blade heating element. The heating element may project into or surround a cavity within the main body for receiving the article/consumable described above.

The device (e.g. the main body) may further comprise an electrical power supply e.g. a (rechargeable) battery for powering the heating element. It may further comprise a control unit to control the supply of power to the heating element. In a fourth aspect, there is provided a method of using a smoking substitute system according to the second aspect, the method comprising inserting the article/consumable into the device, and heating the article/consumable using the heating element.

In some embodiments, the method comprises inserting the article/consumable into a cavity within the main body and penetrating the article/consumable with the heating element upon insertion of the article/consumable. For example, the heating element may penetrate the aerosol-forming substrate in the article/consumable.

The skilled person will appreciate that except where mutually exclusive, a feature or parameter described in relation to any one of the above aspects may be applied to any other aspect. Furthermore, except where mutually exclusive, any feature or parameter described herein may be applied to any aspect and/or combined with any other feature or parameter described herein.

Summary of the Figures

So that the invention may be understood, and so that further aspects and features thereof may be appreciated, embodiments illustrating the principles of the invention will now be discussed in further detail with reference to the accompanying figures, in which:

Figure 1 shows a first embodiment of an HNB consumable;

Figure 2 shows a second embodiment of an HNB consumable

Figure 3 shows a third embodiment of an HNB consumable;

Figure 4 shows the first embodiment within a device forming an HNB system;

Figures 5A and 5B show a perspective and end view, respectively, of the first embodiment of the consumable;

Figures 6, 7 and 8 are end views of exemplary embodiments of a filter element for a HNB consumable.

Detailed Description of the Figures

As shown in Figure 1 , the HNB consumable 1 comprises an aerosol-forming substrate 2 at the upstream end of the consumable 1.

The aerosol-forming substrate comprises reconstituted tobacco which includes nicotine as a volatile compound. The aerosol-forming substrate 2 comprises 65 wt% tobacco which is provided in the form of gathered shreds produced from a sheet of slurry/paper recon tobacco. The tobacco is dosed with 20wt% of a humectant such as propylene glycol (PG) or vegetable glycerine (VG) and has a moisture content of between 7-9 wt%. The aerosol-forming substrate further comprises cellulose pulp filler and guar gum binder.

The aerosol-forming substrate 2 is formed in a substantially cylindrical shape such that the consumable resembles a conventional cigarette. It has diameter of around 7mm and an axial length of around 12 mm.

The aerosol-forming substrate 2 is circumscribed by a paper wrapping layer 3.

The consumable 1 comprises an upstream filter element 4 and a downstream (terminal) filter element 5. The two filter elements 4, 5 and spaced by a cardboard tube spacer 6. Both filter elements 4, 5 are formed of cellulose acetate tow and wrapped with a respective paper plug layer (not shown).

Both filter elements 4, 5 have a substantially cylindrical shape. The diameter of the upstream filter element 4 matches the diameter of the aerosol-forming substrate 2. The diameter of the terminal filter element 5 is slightly larger and matches the combined diameter of the aerosol-forming substrate 2 and the wrapping layer 3. The upstream filter element 4 is slightly shorter in axial length than the terminal filter element 5 at an axial length of 10mm compared to 12mm for the terminal filter element.

The cardboard tube spacer 6 is longer than each of the two filter elements having an axial length of around 14mm.

Each filter element 4, 5 is a hollow bore filter element with a hollow, longitudinally extending bore 7, 8. Although not immediately apparent from the figure, the bore 7 of the upstream filter element 4 has a generally circular transverse cross-section, whilst the bore 8 of the terminal filter element 5 has a noncircular transverse cross-section. This non-circular bore 8, will be described in more detail with reference to figures 5A and 5B.

The cardboard tube spacer 6 and the upstream filter element 4 are circumscribed by the wrapping layer 3.

The terminal filter element 5 is joined to the upstream elements forming the consumable by a circumscribing paper tipping layer 9. The tipping layer 9 encircles the terminal filter element 5 and has an axial length of around 20 mm such that it overlays a portion of the cardboard tube spacer 6.

Figure 2 shows a second embodiment of a consumable T which is the same as that shown in Figure 1 except that the upstream filter element 4 is a solid filter element and comprises a crushable capsule 10 (crush-ball) having a shell wall containing a liquid menthol or cherry or vanilla flavourant. The capsule 10 is spherical and has a diameter of 3.5mm. It is positioned within the axial centre of the upstream filter element 4.

Figure 3 shows a third embodiment of a consumable 1” which is the same as the first embodiment except that the wrapping layer 3 does not completely circumscribe the cardboard tube spacer 6 such that there is an annular gap 1 1 between the tipping layer 9 and the cardboard tube spacer 6 downstream of the end of the wrapping layer 3.

Figure 4 shows the first embodiment inserted into an HNB device 12 comprising a rod-shaped heating element 20. The heating element 20 projects into a cavity 13 within the main body 14 of the device.

The consumable 1 is inserted into the cavity 13 of the main body 14 of the device 12 such that the heating rod 20 penetrates the aerosol-forming substrate 2. Heating of the reconstituted tobacco in the aerosolforming substrate 2 is effected by powering the heating element (e.g. with a rechargeable battery (not shown)). As the tobacco is heated, moisture and volatile compound (e.g. nicotine) within the tobacco and the humectant are released as a vapour and entrained within an airflow generated by inhalation by the user at the terminal filter element 5.

As the vapour cools within the upstream filter element 4 and the cardboard tube spacer 6, it condenses to form an aerosol containing the volatile compounds for inhalation by the user.

Figure 5A is a perspective view of the first embodiment of the consumable 1 , with a portion of the wrapping layer 3 and tipping paper 9 cut away (i.e. for the purpose of showing the internal structure). Figure 5B is an end view of the first embodiment. As is apparent from these figures, the bore 8 of the terminal filter element 5 has a transverse cross-section that has a central portion 15 and a plurality of lobes 16 extending outwardly from the central portion 15 (i.e. so as to define a generally asterisk-shaped cross-section).

Figure 6 shows a further embodiment of a terminal filter 5’. This is the same as the previously described embodiments, except that the bore 8’ of the terminal filter 5’ comprises a heart-shaped transverse cross- section.

The embodiment of the terminal filter 5” shown in Figure 7 comprises three bores 8”. Each of the three bores 8” comprises a transverse cross-section that is triangular in shape.

Figure 8 shows an embodiment of a terminal filter 5’” that comprises four bores 8’”, 8””. In particular, the terminal filter 5’” comprises two bores 8’” that each have a transverse cross-section that is star-shaped, and two bores 8”” that each have a transverse cross-section that is square-shaped.

The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the scope of the invention.

For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

Throughout this specification, including the claims which follow, unless the context requires otherwise, the words“have”,“comprise”, and“include”, and variations such as“having”,“comprises”,“comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

It must be noted that, as used in the specification and the appended claims, the singular forms“a,”“an,” and“the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from“about” one particular value, and/or to“about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent“about,” it will be understood that the particular value forms another embodiment. The term“about” in relation to a numerical value is optional and means, for example, +/- 10%.

The words "preferred" and "preferably" are used herein refer to embodiments of the invention that may provide certain benefits under some circumstances. It is to be appreciated, however, that other embodiments may also be preferred under the same or different circumstances. The recitation of one or more preferred embodiments therefore does not mean or imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure, or from the scope of the claims.

Claims

Claims:

1. A filter element for an aerosol-forming article, the filter element comprising a bundle of filter tows with a bore extending longitudinally therethrough, at least a portion of the bore having a non-circular transverse cross-section.

2. A filter element according to claim 1 wherein the transverse cross-section of the at least a portion of the bore comprises a central portion and a plurality of lobes projecting outwardly from the central portion.

3. A filter element according to any one of the preceding claims wherein the transverse cross-section of at least a portion of the bore is any one of a square, triangle, heart shape, star shape or asterisk shape.

4. A filter element according to any one of the preceding claims wherein the transverse cross-sectional area of the bore is substantially uniform for the entire axial length of the bore.

5. A filter element according to any one of the preceding claims wherein the shape of the transverse cross-section of the bore is substantially uniform for the entire length of the bore.

6. A filter element according to any one of the preceding claims comprising a plurality of bores, at least a portion of each of the plurality of bores having a non-circular transverse cross-section.

7. An aerosol-forming article comprising an aerosol-forming substrate and a filter element according to any one of the preceding claims downstream of the aerosol-forming substrate.

8. An aerosol-forming article according to claim 7 wherein the filter element is a terminal filter element located at a downstream axial end of the aerosol-forming article.

9. An aerosol-forming article according to claim 7 or 8 that is a heat-not-burn (HNB) consumable.

10. A system comprising an aerosol-forming article according to any one of the preceding claims and a device comprising a heating element.

1 1. A system according to claim 10 wherein the device comprises a main body for housing the heating element and the heating element comprises an elongated heating element.

12. A method of using the system according to claim 10 or 1 1 , the method comprising:

a. inserting the article into the device; and

b. heating the article using the heating element.

13. A method according to claim 12 comprising inserting the article into a cavity within a main body of the device and penetrating the article with the heating element upon insertion of the article.