Aerosol-generating article with concave internal wall

Abstract

An aerosol-generating article is for use with an aerosol-generating device to generate an aerosol. The aerosol-generating article may be defined by a first planar dimension, a second planar dimension, and a thickness, in which both the first planar dimension and the second planar dimension are at least three times the magnitude of the thickness. An airflow channel is defined through the aerosol-generating article between an airflow inlet and an airflow outlet. A proximal portion of the airflow channel diverges laterally between the airflow inlet and a central portion of the airflow channel, and a distal portion of the airflow channel converges laterally between the central portion of the airflow channel to the airflow outlet.

Description

[0001] AEROSOL-GENERATING ARTICLE WITH CONCAVE INTERNAL WALL

[0002] The present disclosure relates to an aerosol-generating article comprising an aerosolforming substrate.

[0003] A typical aerosol-generating article may appear similar to a conventional cigarette. For example, such an aerosol-generating article may be substantially cylindrical and comprise an aerosol-forming substrate and other components such as a mouthpiece filter element and a cooling element, all arranged together in the form of a rod and wrapped in a cigarette paper. Dimensions of typical aerosol-generating articles are often similar to the dimensions of conventional cigarettes.

[0004] However, a significant portion of the aerosol-forming substrate in these cylindrical aerosolgenerating articles may not be sufficiently heated to form an aerosol during use. This is undesirable since the insufficiently heated portion of the aerosol-forming substrate contributes to the cost of manufacture and transport of the aerosol-generating article, but does not contribute to the aerosol delivered to an end user. This may be the case regardless of the way in which the aerosol-forming substrate is heated, for example regardless of whether a resistive or inductive heater is used and regardless of whether the aerosol-forming substrate is heated from the inside or the outside. Moreover, the components of these cylindrical aerosol-generating articles normally need to have the same or very similar outer diameters so that they can be brought together, accurately positioned in co-axial alignment and wrapped in a cigarette paper. This can lead to increased cost and complexity of manufacture.

[0005] It is an aim of the present disclosure to provide an aerosol-generating article, in which a greater portion of an aerosol-forming substrate of the aerosol-generating article is sufficiently heated to form an aerosol during use. It is also an objective of the present disclosure to provide an aerosol-generating article that can be manufactured relatively efficiently and cheaply.

[0006] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising an aerosol-forming substrate for producing an aerosol, the aerosol-generating article being a planar aerosol-generating article having a base defined by a length extending in an x direction, a width extending in a y direction, and a height extending in a z direction.

[0007] The height of the aerosol-generating article is less than both of the length and width of the aerosol-generating article. For the purpose of the present disclosure, the “height” of the aerosolgenerating article may also be referred to as the “thickness” of the aerosol-generating article.

[0008] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising an aerosol-forming substrate for producing an aerosol, the aerosol-generating article comprising a substantially planar upper surface defined by a length extending in an x direction and a width extending in a y direction, and a substantially planar lower surface defined by a length extending in an x direction and a width extending in a y direction. The substantially planar upper surface and the substantially planar lower surface may be vertically spaced from each other by a height defined in a z direction.

[0009] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosolgenerating article defined by a first planar dimension, a second planar dimension, and a thickness, in which both the first planar dimension and the second planar dimension are at least three times the magnitude of the thickness, in which an airflow channel is defined through the aerosol-generating article between an airflow inlet and an airflow outlet, and in which a proximal portion of the airflow channel diverges laterally between the airflow inlet and a central portion of the airflow channel, and a distal portion of the airflow channel converges laterally between the central portion of the airflow channel to the airflow outlet.

[0010] The first planar dimension may be a length and the second planar dimension may be a width. The airflow channel may extend longitudinally between the air inlet and the air outlet, for example in which the air inlet is defined in a first end face of the article and the air outlet is defined in a second end face of the article. Thus, the airflow channel may extend through the article in a lengthwise direction.

[0011] Alternatively, the airflow channel may extend laterally between the air inlet and the air outlet, for example in which the air inlet is defined in a first side face of the article and the air outlet is defined in a second side face of the article. Thus, the airflow channel may extend through the article in a transverse or lateral direction.

[0012] The proximal portion of the airflow channel diverges laterally between the airflow inlet and a central portion of the airflow channel, and the distal portion of the airflow channel converges laterally between the central portion of the airflow channel to the airflow outlet. Advantageously, the resulting airflow through the airflow channel of the aerosol-generating article may be laminar. Accordingly, there may be minimal mixing between air flowing adjacent to a wall of the airflow channel and air flow more centrally within the airflow channel. Airflow adjacent to the wall of the airflow channel may be cooled to a greater degree compared to airflow towards the centre of the airflow channel due to proximity with the wall and the ambient environment. With laminar airflow, airflow towards the centre of the airflow channel may remain at a desired temperature for better delivery of volatiles, such as nicotine and aerosol formers including glycerine.

[0013] Vapour in an airflow at a lower temperature may be more likely to condense to form large droplets of liquid aerosol-forming substrate compared to vapour in an airflow at a higher temperature. Accordingly, laminar airflow in a converging section of the cavity downstream of an aerosol-forming material may result in less mixing of cooler airflow at the sides of the airflow channel and warmer airflow towards the centre of the airflow channel, which may advantageously reduce condensation of vapour. There may be a reduction of undesirable delivery of large droplets of liquid aerosol-forming substrate to a user.

[0014] Laminar airflow through the airflow channel may be particularly desirable during the initial puffs of a user experience. During the initial puffs, the walls of the aerosol-generating article may be at ambient temperature. During use of the aerosol-generating article, the walls of the aerosol-generating article may heat up. Vapour during the initial puffs may therefore be more likely to condense than vapour during subsequent puffs. Accordingly, laminar airflow may be particularly advantageous to avoid undesirable delivery of large droplets of liquid aerosolforming substrate to a user during initial puffs and to improve delivery of volatiles.

[0015] The aerosol-generating article may comprise a frame. Advantageously, the frame may allow the aerosol-generating article to be relatively thin whilst maintaining structural rigidity.

[0016] Where the aerosol-generating article comprises a frame at least partially defining the diverging and converging sections of the airflow channel, these parts or sections of the frame may have increased width and radial thickness compared to other parts of the frame. This may improve the structural rigidity of the frame and of the aerosol-generating article.

[0017] Increasing the radial thickness or width of sections of the frame may advantageously reduce the permeability of the frame. Reducing the permeability of the frame may improve sealing of the one or more aerosol-generating substrates of the aerosol-generating article to improve the shelf-life of the aerosol-generating article and improve the quality and quantity of aerosol delivered to a user. Reducing the permeability of the frame may ensure air and aerosol travel along desired airflow pathways through the aerosol-generating article. This may improve the quality and quantity of aerosol delivered to a user.

[0018] Preferably, the article comprises an upper surface, a lower surface, a first end face, a second end face, a first side face and a second side face, and an airflow path defined through the article between the upper surface and the lower surface. The airflow path is defined by the airflow channel extending between the airflow inlet and the airflow outlet.

[0019] The airflow channel may be defined by a left lateral wall extending from a left side of the air inlet to a left side of the air outlet, and a right lateral wall extending from a right side of the air inlet to a right side of the air outlet. One, or both, of the left lateral wall and the right lateral wall may comprise a proximal portion that diverges away from a lateral centre line of the article and a distal portion that converges towards the lateral centre line of the article. One or both of the lateral side walls may be described as concave.

[0020] Optionally, the left lateral wall may be substantially trapezoidal in shape, for example shaped like a trapezium in plan view extending between the air inlet and the air outlet. Optionally, the right lateral wall may be substantially trapezoidal in shape, for example shaped like a trapezium in plan view extending between the air inlet and the air outlet.

[0021] Optionally, the left lateral wall may be curved in shape, for example substantially sinusoidal in shape, for example shaped like a sine curve in plan view extending between the air inlet and the air outlet. Optionally, the right lateral wall may be curved in shape, for example substantially sinusoidal in shape, for example shaped like a sine curve in plan view extending between the air inlet and the air outlet.

[0022] The shape of the cavity may be symmetrical with respect to a longitudinal centre axis the shape of the cavity may be symmetrical with respect to a lateral centre axis.

[0023] Advantageously, the shape of the proximal portion of the left lateral wall may conform to the shape of the distal portion of the right lateral wall, and the shape of the proximal portion of the right lateral wall may conform to the shape of the distal portion of the left lateral wall. This configuration may provide benefits in manufacture. For example, the airflow channel or cavity of the article may be formed by cutting, in a frame material such as card, a line having periodic features. The periodic features may be, for example, a repeating sine curve or a repeating trapezoid curve. Cut portions of the frame material may then be translated by half a wavelength of the repeating feature to form a series of shaped cavities. Such a manufacturing process may simplify manufacture and help reduce wasted material.

[0024] The lateral divergence of the airflow channel may be greater at the proximal portion than at the centre portion. The lateral convergence of the airflow channel may be greater at the distal portion than the centre portion.

[0025] The first planar dimension may be greater than, or equal to, the second planar dimension, in which case the aerosol-generating article may be substantially cuboid or parallelepiped in shape. The aerosol-generating article may be substantially rectangular in plan view.

[0026] The airflow channel may be substantially hexagonal in plan view, for example substantially an irregular hexagon in plan view.

[0027] The airflow channel may have a width defined by lateral side walls and a height defined by upper and lower walls. The height may be substantially constant whereas the width varies between the air inlet and the air outlet as the sidewalls diverge and converge.

[0028] The proximal portion of the article may extend for between 0.2 and 0.5 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension. The proximal portion of the article may extend for between 0.25 and 0.33 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

[0029] The distal portion of the article may extend for between 0.2 and 0.5 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension. The distal portion of the article may extend for between 0.25 and 0.33 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

[0030] The central portion of the article may extend for between 0.1 and 0.6 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension. The central portion of the article may extend for between 0.2 and 0.33 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

[0031] Optionally, an aerosol-forming substrate, for example an aerosol-forming material, is located within the airflow channel, preferably within the central portion of the airflow channel. The airflow channel may comprise or form a cavity for receiving the aerosol-forming substrate.

[0032] Optionally, an aerosol-forming substrate, for example an aerosol-forming material, forms part of one or more walls of the airflow channel.

[0033] Aerosol-generating articles according to the present disclosure may preferably be substantially flat articles or substantially planar articles. Such articles have a large base area relative to the volume of the article. In particular, the height of the aerosol-generating article may be less than 50 percent of both the length and width of the aerosol-generating article. Advantageously, a larger base area may provide greater surface area for heating by a planar heater of an aerosol-generating device. Advantageously, a smaller height may allow a smaller temperature gradient or difference across the height of the aerosol-generating article during heating. For example, where the base of the aerosol-generating article is in contact with, and heated by, a planar heater, there may be a smaller temperature difference between the base and an upper surface opposing the base if the spacing, or height, between the base and the upper surface is smaller. Advantageously, this may allow heating of a greater proportion of the aerosolforming substrate of the aerosol-generating article to a temperature at which an aerosol is released, whilst minimising the risk of burning the hottest portion of the substrate closest to the heater. Alternatively, or in addition, this may reduce a time required to heat the aerosol-forming substrate sufficiently to release an aerosol.

[0034] The aerosol-generating article according to any of the aspects disclosed herein may have an air flow path extending through the aerosol-generating article. The aerosol-generating article may have an air-flow path defined through the aerosol-generating article in an x / y plane from one side of the aerosol-generating article to the other side of the aerosol-generating article. The aerosol-generating article preferably has a resistance to draw (RTD) of less than 20 millimetre H2O, for example less than 10 millimetre H2O, in the direction of the airflow path. Preferably, the aerosol-generating article has a RTD of less than 20 millimetre H2O, for example less than 10 millimetre H2O, in at least one direction in an x / y plane of the aerosol-generating article. An aerosol-generating article with a low resistance air-flow path may allow for superior air-flow management and allow aerosol to be extracted more efficiently from the aerosol-generating article and guided to a user. Unless otherwise specified, the resistance to draw (RTD) is measured in accordance with ISO 6565-2015. The RTD refers to the pressure required to force air through the full length of a component, such as the aerosol-generating article. The terms “pressure drop” or “draw resistance” of a component or article may also refer to the “resistance to draw”. Such terms generally refer to the measurements made in accordance with ISO 6565-2015 and are normally carried out at under test at a volumetric flow rate of about 17.5 millilitres per second at the output or downstream end of the measured component at a temperature of about 22 degrees Celsius, a pressure of about 101 kPa (about 760 Torr) and a relative humidity of about 60%.

[0035] The aerosol-generating article according to any of the aspects disclosed herein may comprise substantially planar upper and lower surfaces. A vertical separation between the substantially planar upper and lower surfaces may define a height (for example, a z dimension) of the aerosol-generating article. An air flow channel may be defined between the substantially planar upper and lower surfaces. The height of the aerosol-generating article may be less than 5 millimetres, for example between 1.5 millimetres and 5 millimetres, for example between 1.5 millimetres and 4 millimetres, for example between 1.5 millimetres and 3 millimetres, for example between 1.5 millimetres and 2 millimetres. One or both of the substantially planar upper and lower surfaces may comprise an aerosol-forming substrate. The aerosol-generating article may comprise upper and lower layers, the upper layer forming the substantially planar upper surface and the lower layer forming the substantially planar lower surface. At least one of the upper and lower layers may comprise or consist of aerosol-forming substrate

[0036] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosolgenerating article comprising a first planar layer, a second planar layer, and a corrugated layer arranged between the first planar layer and the second planar layer. At least one of the first planar layer, the second planar layer and the corrugated layer may comprise or consist of an aerosol-forming substrate.

[0037] The use of a corrugated structure in the aerosol-generating article may advantageously allow the production of an aerosol-generating article that has extremely low RTD while still being sufficiently rigid to for a user to handle. Further, use of a corrugated structure may allow a low density, low RTD, aerosol-generating article to be produced using high speed production methods similar to those used for production of corrugated cardboard.

[0038] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol. The aerosolgenerating article may comprise a first planar external surface, a second planar external surface, a cavity and a frame. The frame is positioned between the first planar external surface and the second planar external surface. The frame at least partially defines the cavity. The aerosol-generating article comprises an aerosol-forming substrate. The aerosol-generating article may comprise an air inlet and an air outlet, and an airflow passage or channel extending between the air inlet and the air outlet through the cavity. Thus, the cavity may be formed by the airflow channel.

[0039] Preferably, an aerosol-forming substrate is positioned between the first planar external surface and the second planar external surface.

[0040] The frame may comprise a peripheral wall at least partially circumscribing or encircling the cavity. The frame may comprise a peripheral wall wholly circumscribing or encircling the cavity. Advantageously, the frame may allow the aerosol-generating article to be relatively thin whilst maintaining structural rigidity.

[0041] The aerosol-generating article may comprise a first planar external layer and a second planar external layer, in which the first planar external layer forms the first planar external surface, and the second planar external layer forms the second planar external surface. Optionally, at least one of the first planar external layer, the second planar external layer, and the frame may comprise or consist of aerosol-forming substrate.

[0042] The cavity may be substantially empty.

[0043] Aerosol-forming substrate may be positioned within the cavity.

[0044] A corrugated layer may be positioned within the cavity.

[0045] The frame may be a planar frame.

[0046] The frame may have a height between 50 percent and 95 percent of the height of the aerosol-generating article. The frame may have a height between 60 percent and 95 percent of the height of the aerosol-generating article. The frame may have a height between 70 percent and 95 percent of the height of the aerosol-generating article. The frame may have a height between 80 percent and 95 percent of the height of the aerosol-generating article.

[0047] The frame may have a height between 1 millimetre and 5.5 millimetres. The frame may have a height between 1 millimetre and 5 millimetres. Preferably, the frame may have a height between 1.5 millimetres and 5 millimetres.

[0048] The frame may be made from or comprise a biodegradable material. The frame may be made entirely from a biodegradable material.

[0049] The frame may be made from or comprise a cellulosic material. The cellulosic material may comprise a sheet of cellulosic material. The cellulosic material may comprise cellulose fibres. The cellulosic material may be paper, paperboard, or cardboard. The frame may be made from or comprise a plant material, such as tobacco. The frame may be made entirely from a cellulosic material.

[0050] The frame may be a unitary component. Alternatively, the frame may comprise two or more layers. That is, the frame may have a laminated structure. The aerosol-generating article of any of the aspects of the present disclosure may have a length (for example, an x dimension) of between 10 millimetres and 100 millimetres, or between 10 millimetres and 50 millimetres, for example between 10 millimetres and 40 millimetres, for example between 12 millimetres and 30 millimetres, for example between 14 millimetres and 26 millimetres, for example between 16 millimetres and 24 millimetres, for example between 18 millimetres and 22 millimetres, for example about 18 millimetres, or about 19 millimetres, or about 20 millimetres, or about 21 millimetres, or about 22 millimetres. The length may be about 29 mm, or about 30 mm, or about 31 mm.

[0051] The aerosol-generating article may have a width (for example, a y dimension) of between 5 millimetres and 20 millimetres, for example between 8 millimetres and 18 millimetres, for example between 10 millimetres and 16 millimetres, for example between 11 millimetres and 15 millimetres, for example between 12 millimetres and 14 millimetres, for example about 13 millimetres. The width may be about 10 mm, or about 11 mm, or about 12 mm.

[0052] The aerosol-generating article may have a height (for example, a z dimension) of between 1 millimetres and 10 millimetres, for example between 1.2 millimetres and 8 millimetres, for example between 1.4 millimetres and 7 millimetres, for example between 1.6 millimetres and 6 millimetres, for example between 1.7 millimetres and 5 millimetres, for example about 1.7 millimetres, or about 4.5 millimetres, or about 2 millimetres, or about 3 millimetres, or about 4 millimetres.

[0053] The aerosol-generating article of any of the aspects of the present disclosure when viewed in plan may have a shape defining a polygon, a quadrilateral (for example, a rectangle or a square), an oval, a circle, or a combination thereof. Where the aerosolgenerating article comprises substantially planar upper and lower surfaces, one or both of the upper and lower surfaces when viewed in plan may have a shape defining a polygon, a quadrilateral (for example, a rectangle or a square), an oval, a circle, or a combination thereof. A perimeter of the aerosol-generating article when viewed in plan may be formed of a plurality of straight sides, a plurality of curved sides, or a combination of straight and curved sides. Where the aerosol-generating article comprises substantially planar upper and lower surfaces, a perimeter of one or both of the upper and lower surfaces when viewed in plan may have a shape defining a polygon, a quadrilateral (for example, a rectangle or a square), an oval, a circle, or a combination thereof.

[0054] The aerosol-generating article may consist entirely of aerosol-forming substrate. Alternatively, the aerosol-forming substrate may be one of a plurality of component parts of the aerosol-generating article.

[0055] The aerosol-forming substrate may comprise nicotine. Nicotine may be present in the form of a tobacco material or may be in the form of a nicotine extract. The aerosol-forming substrate may comprise one or more organic materials such as tobacco, mint, tea and cloves. The aerosol-forming substrate may comprise one or more of: herb leaf, tobacco leaf, fragments of tobacco ribs, reconstituted tobacco, homogenised tobacco such as cast leaf, extruded tobacco, expanded tobacco, aerosol-generating films and gel compositions.

[0056] The aerosol-forming substrate may comprise or consist of homogenised tobacco material, for example a reconstituted tobacco material or a cast leaf tobacco material.

[0057] The aerosol-forming substrate may be in the form of shredded aerosol-generating material. The shredded aerosol-generating material may comprise one or more of: strips and strands of aerosol-generating material, such as strips and strands of tobacco or homogenised tobacco material. The shredded aerosol-generating material may be in the form of a shredded sheet of homogenised tobacco material.

[0058] The aerosol-forming substrate may be cut filler. The aerosol-forming substrate may be tobacco cut filler. The cut filler may comprise one or more of bright tobacco, dark tobacco, aromatic tobacco and filler tobacco. Examples of bright tobaccos are Flue-Cured Brazil, Indian Flue-Cured, Chinese Flue-Cured, US Flue-Cured such as Virginia tobacco, and Flue-Cured from Tanzania. Examples of aromatic tobaccos are Oriental Turkey, Greek Oriental, semi-oriental tobacco but also Fire Cured, US Burley, such as Perique, and Rustica. Examples of dark tobacco are Dark Cured Brazil Galpao, Burley Malawi or other African Burley, Sun Cured or Air Cured Indonesian Kasturi. As used herein, the term “cut filler” is used to describe a blend of shredded plant material, such as tobacco plant material, including, in particular, one or more of leaf lamina, processed stems and ribs, homogenised plant material.

[0059] The aerosol-forming substrate may be in the form of a sheet of aerosol-generating material. As used herein, the term “sheet” describes a laminar element having a width and length substantially greater than the thickness thereof. The sheet of aerosol-generating material may be a sheet of plant material. The sheet of aerosol-generating material may be a sheet of tobacco material. The sheet of aerosol-generating material may be a sheet of homogenised tobacco material, such as a cast leaf sheet.

[0060] The aerosol-forming substrate may comprise a bound collection of strips, strands or particles of tobacco material. The aerosol-forming substrate may be in the form of a compressed plug of tobacco material; for example, in which a plug having a substantially circular cross-section in an initial state of the plug is compressed into a flatter cross-sectional profile in a subsequent state of the plug. The tobacco material may be enclosed by a wrapper. The aerosol-forming substrate may be in the form of strips, strands or particles of tobacco material bound together in a binder matrix.

[0061] The aerosol-forming substrate may comprise one or more aerosol-formers. Suitable aerosol-formers are well known in the art and include, but are not limited to, one or more aerosolformers selected from: polyhydric alcohols, such as propylene glycol, polyethylene glycol, triethylene glycol, 1 , 3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate. It may be particularly preferable for the aerosol-former to be or comprise one or both of glycerine and propylene glycol. The aerosol former may consist of glycerine or propylene glycol or of a combination of glycerine and propylene glycol.

[0062] The aerosol-forming substrate may have an aerosol-former content greater than or equal to 1 , 2, 5, 10, or 15 percent by weight on a dry weight basis. The aerosol-forming substrate may have an aerosol-former content greater than or equal to 15 percent by weight on a dry weight basis, for example greater than 20 by weight on a dry weight basis, or greater than 25 by weight on a dry weight basis, or greater than 30 by weight on a dry weight basis, or greater than 40 by weight on a dry weight basis, or greater than 50 by weight on a dry weight basis.

[0063] The aerosol-forming substrate may have an aerosol-former content less than or equal to 30 percent by weight on a dry weight basis, less than or equal to 25 percent by weight on a dry weight basis, or less than or equal to 20 percent by weight on a dry weight basis. That is, the aerosol-generating material may have an aerosol-former content less than or equal to 30 by weight on a dry weight basis, less than or equal to 25 by weight on a dry weight basis, or less than or equal to 20 by weight on a dry weight basis.

[0064] The aerosol-forming substrate may have an aerosol-former content between 1 percent and 30 percent by weight on a dry weight basis, between 1 percent and 25 percent by weight on a dry weight basis, or between 1 percent and 20 percent by weight on a dry weight basis.

[0065] The aerosol-forming substrate may comprise at least 50 percent by weight of aerosol former, at least 60 percent by weight of aerosol former, or at least 70 percent by weight of aerosol former.

[0066] The aerosol-forming substrate may comprise less than or equal to 85 percent by weight of aerosol former, less than or equal to 80 percent by weight of aerosol former, or less than or equal to 75 percent by weight of aerosol former.

[0067] The aerosol-forming substrate may comprise between 50 percent and 85 percent by weight of aerosol former, between 50 percent and 80 percent by weight of aerosol former, or between 50 percent and 75 percent by weight of aerosol former.

[0068] The aerosol-forming substrate may comprise nicotine. The aerosol-forming substrate may comprise natural nicotine, or synthetic nicotine, or a combination of natural nicotine and synthetic nicotine.

[0069] The aerosol-forming substrate may comprise at least 0.5 percent by weight of nicotine, at least 1 percent by weight of nicotine, at least 1.5 percent by weight of nicotine, or at least 2 percent by weight of nicotine. The aerosol-forming substrate may comprise one or more flavourants. The one or more flavourants may comprise one or more of: one or more essential oils such as eugenol, peppermint oil and spearmint oil; one or both of menthol and eugenol; one or both of anethole and linalool; and a herbaceous material. Suitable herbaceous material includes herb leaf or other herbaceous material from herbaceous plants including, but not limited to, mints, such as peppermint and spearmint, lemon balm, basil, cinnamon, lemon basil, chive, coriander, lavender, sage, tea, thyme, and caraway. The one or more flavourants may comprise a tobacco material.

[0070] The aerosol-forming substrate may comprise one or more botanicals. For example, the aerosol-forming substrate may comprise about 1 to 90 %, for example about 15 to 55 %, preferably of about 20 to 35 %, of botanicals such as Clove, Echinacea sp., Fennel, Ginger, Hawthorn berry, Elderberry, Monarda, Mullein leaves, Nettle, Plantain, Turmeric, Yarrow, Rooibos, Star Anise, Thyme, Anethum, Chamomile and compounds of those.

[0071] The aerosol-forming substrate may have a moisture content of about 5 to 25%, preferably of about 7 to 15%, at final product state. For example, the aerosol-forming substrate may be a homogenised tobacco material with a moisture of about 5 to 25%, preferably of about 7 to 15%, at final product state.

[0072] The aerosol-forming substrate may comprise a binder. For example, the aerosol-forming substrate may comprise about 1 to 10%, preferably of about 1 to 5%, of a binder such as any of common gums or pectins used in food and beverage (F&B) industries. Preferred binders may be natural pectins, such as fruit, for example citrus, or tobacco pectins; guar gums, land locust bean gums, such as hydroxyethyl and / or hydroxypropyl of those; starches, such as modified or derivatized starches; alginate; methyl, ethyl, ethylhydroxymethyl and carboxy methyl, celluloses; dextran; and xanthan gum. A preferable binder is guar.

[0073] The aerosol-forming substrate may comprise, or consist of, a solid aerosol-forming material. The aerosol-forming substrate may comprise a liquid aerosol-forming material, for example a liquid aerosol-forming material retained within a porous matrix. The aerosol-forming substrate may comprise a gel aerosol-forming material.

[0074] According to the present disclosure, an aerosol-generating device for receiving an aerosol-generating article as disclosed herein, or an aerosol-forming substrate as disclosed herein, may comprise a cavity dimensioned to receive at least a portion of the aerosol-generating article or aerosol-forming substrate, a heater or heating means, a power source for supplying power to the heater or heating means, and a controller to control supply of power to the heater or heating means. The aerosol-generating device is configured to heat an aerosol-forming substrate, for example an aerosol-forming substrate that is a component part of an aerosol-generating article, to form an aerosol, for example an inhalable aerosol.

[0075] The aerosol-generating device may preferably be configured to receive the entirety of the aerosol-generating article such that the aerosol-generating article is wholly enclosed within the aerosol-generating device. The cavity may comprise an opening into which a distal end of the aerosolgenerating article can be inserted. The cavity may have any suitable cross-sectional shape. For example, the cavity may have a rectangular transverse cross-section, for example a rectangular cross-section having opposing top and bottom sides that are greater in length than left and right sides.

[0076] Preferably, at least one internal surface of the cavity is a heating surface configured to heat an aerosol-generating article. The heating surface may comprise a heater, for example a resistance heater, or an infra-red heater, or a susceptor configured to be heated by engagement with an inductor. The heating surface may comprise an inductor, for example the surface may comprise a coil arranged to generate a fluctuating electromagnetic field within a space of the cavity. The heating surface may be a surface that is permeable to a fluctuating electromagnetic field, such that an inductor arranged outside the cavity can project a fluctuating electromagnetic field through the heating surface to engage with a susceptor arranged within the cavity.

[0077] As used herein, the term “aerosol-generating article” may refer to an article able to generate, or release, an aerosol.

[0078] As used herein, the term “aerosol-forming substrate” may refer to a substrate capable of releasing an aerosol or volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. An aerosol-forming substrate may comprise an aerosol-forming material. An aerosol-forming substrate may be adsorbed, coated, impregnated, or otherwise loaded onto a carrier or support. An aerosol-forming substrate may conveniently be part of an aerosol-generating article or smoking article.

[0079] As used herein, the term “aerosol-generating device” may refer to a device for use with an aerosol-generating article to enable the generation, or release, of an aerosol.

[0080] As used herein, the term “aerosol generating system” refers to a combination of an aerosol-generating device and one or more aerosol-forming articles for use with the device. An aerosol-generating system may include additional components, such as a charging unit for recharging an on-board electric power supply in an electrically operated or electric aerosol-generating device.

[0081] As used herein, the term “aerosol former” may refer to any suitable known compound or mixture of compounds that, in use, facilitates formation of an aerosol. The aerosol may be a dense and stable aerosol. The aerosol may be substantially resistant to thermal degradation at the operating temperature of the aerosol-forming substrate or aerosol-generating article.

[0082] As used herein with reference to the invention, the term “nicotine”, is used to describe nicotine, nicotine base or a nicotine salt. As used herein with reference to the invention, the terms “proximal”, “distal”, “upstream” and “downstream” are used to describe the relative positions of components, or portions of components, of the aerosol-generating article.

[0083] As used herein, the term “longitudinal” refers to the direction corresponding to the main longitudinal axis of the aerosol-generating article, which extends between the upstream and downstream ends of the aerosol-generating article. During use, air may be drawn through the aerosol-generating article in the longitudinal direction.

[0084] As used herein, the term “sheet” denotes a laminar element having a width and length substantially greater than the thickness thereof. The width of a sheet may be greater than 10 mm, preferably greater than 20 mm or 30 mm. In certain embodiments, sheets of material for use in forming aerosol-forming substrates as described herein may have a thickness of between 10 pm and about 1000 pm, for example between 10 pm and about 300 pm.

[0085] As used herein, the term “homogenised tobacco material” encompasses any tobacco material formed by the agglomeration of particles of tobacco material. Sheets or webs of homogenised tobacco material are formed by agglomerating particulate tobacco obtained by grinding or otherwise powdering of one or both of tobacco leaf lamina and tobacco leaf stems. In addition, homogenised tobacco material may comprise a minor quantity of one or more of tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the treating, handling and shipping of tobacco. The sheets of homogenised tobacco material may be produced by casting, extrusion, paper making processes or other any other suitable processes known in the art.

[0086] The term “cast leaf” is used herein to refer to a product made by a casting process that is based on casting a slurry comprising plant particles (for example, clove particles or tobacco particles and clove particles in a mixture) and a binder (for example, guar gum) onto a supportive surface, such as a belt conveyor, drying the slurry and removing the dried sheet from the supportive surface. An example of the casting or cast leaf process is described in, for example, US-A-5,724,998 for making cast leaf tobacco. In a cast leaf process, particulate plant materials are produced by pulverizing, grinding, or comminuting parts of the plant. The particles produced from one or more plants are mixed with a liquid component, typically water, to form a slurry. Other components in the slurry may include fibres, a binder and an aerosol former. The particulate plant materials may be agglomerated in the presence of the binder. The slurry is cast onto a supportive surface and dried into a sheet of homogenized plant material. Preferably, homogenized plant material used in articles according to the present invention may be produced by casting. Such homogenized plant material may comprise agglomerated particulate plant material.

[0087] As used herein, resistance to draw is expressed with the units of pressure “mm H2O” or “mm WG” or “mm of water gauge” and may be measured in accordance with ISO 6565:2002. The invention is defined in the claims. However, below there is provided a non- exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0088] Ex1. An aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article defined by a first planar dimension, a second planar dimension, and a thickness, in which both the first planar dimension and the second planar dimension are at least three times the magnitude of the thickness, in which an airflow channel is defined through the aerosol-generating article between an airflow inlet and an airflow outlet, and in which a proximal portion of the airflow channel diverges laterally between the airflow inlet and a central portion of the airflow channel, and a distal portion of the airflow channel converges laterally between the central portion of the airflow channel to the airflow outlet.

[0089] Ex2. An aerosol-generating article according to Ex1 in which the first planar dimension is a length and the second planar dimension is a width, in which the airflow channel extends longitudinally between the air inlet and the air outlet, for example in which the air inlet is defined in a first end face of the article and the air outlet is defined in a second end face of the article.

[0090] Ex3. An aerosol-generating article according to Ex1 in which the first planar dimension is a length and the second planar dimension is a width, in which the airflow channel extends laterally between the air inlet and the air outlet, for example in which the air inlet is defined in a first side face of the article and the air outlet is defined in a second side face of the article.

[0091] Ex4. An aerosol-generating article according to any preceding example in which the article comprises an upper surface, a lower surface, a first end face, a second end face, a first side face and a second side face, and an airflow path defined through the article between the upper surface and the lower surface, the airflow path defined by the airflow channel extending between the airflow inlet and the airflow outlet.

[0092] Ex5. An aerosol-generating article according to any preceding example, in which the airflow channel is defined by a left lateral wall extending from a left side of the air inlet to a left side of the air outlet, and a right lateral wall extending from a right side of the air inlet to a right side of the air outlet.

[0093] Ex6. An aerosol-generating article according to Ex5 in which one or both of the left lateral wall and the right lateral wall comprises a proximal portion that diverges away from a lateral centre line of the article and a distal portion that converges towards the lateral centre line of the article. Ex7. An aerosol-generating article according to Ex5 or Ex6 in which the left lateral wall is substantially trapezoidal in shape, for example shaped like a trapezium in plan view extending between the air inlet and the air outlet.

[0094] Ex8. An aerosol-generating article according to any of Ex5 to Ex7 in which the right lateral wall is substantially trapezoidal in shape, for example shaped like a trapezium in plan view extending between the air inlet and the air outlet.

[0095] Ex9. An aerosol-generating article according to Ex5 or Ex6 in which the left lateral wall is substantially sinusoidal in shape, for example shaped like a sine curve in plan view extending between the air inlet and the air outlet.

[0096] Ex10. An aerosol-generating article according to any of Ex5 to Ex7 in which the right lateral wall is substantially sinusoidal in shape, for example shaped like a sine curve in plan view extending between the air inlet and the air outlet.

[0097] ExIOA.An aerosol-generating article according to any of Ex5 to Ex10 in which the shape of the airflow channel is symmetrical with respect to a longitudinal centre axis, and / or in which the in which the shape of the airflow channel is symmetrical with respect to a lateral centre axis.

[0098] ExIOB.An aerosol-generating article according to any of Ex6 to Ex10A in which the shape of the proximal portion of the left lateral wall conforms to the shape of the distal portion of the right lateral wall, and the which the shape of the proximal portion of the right lateral wall conforms to the shape of the distal portion of the left lateral wall.

[0099] Ex11. An aerosol-generating article according to any preceding example in which the lateral divergence of the airflow channel is greater at the proximal portion than the centre portion.

[0100] Ex12. An aerosol-generating article according to any preceding example in which the lateral convergence of the airflow channel is greater at the distal portion than the centre portion.

[0101] Ex13. An aerosol-generating article according to any preceding example in which the first planar dimension is greater than, or equal to, the second planar dimension, in which the aerosol-generating article is substantially cuboid.

[0102] Ex14. An aerosol-generating article according to any preceding example in which the aerosol-generating article is substantially rectangular in plan view.

[0103] Ex15. An aerosol-generating article according to Ex14 in which the airflow channel is substantially hexagonal in plan view, for example substantially an irregular hexagon in plan view.

[0104] Ex16. An aerosol-generating article according to any preceding example in which the airflow channel has a width defined by lateral side walls and a height defined by upper and lower walls, in which the height is substantially constant whereas the width varies between the air inlet and the air outlet as the sidewalls diverge and converge.

[0105] Ex17. An aerosol-generating article according to any preceding example in which the proximal portion of the article extends for between 0.2 and 0.5 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

[0106] Ex18. An aerosol-generating article according to Ex17 in which in which the proximal portion of the article extends for between 0.25 and 0.33 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

[0107] Ex19. An aerosol-generating article according to any preceding example in which the distal portion of the article extends for between 0.2 and 0.5 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

[0108] Ex20. An aerosol-generating article according to Ex19 in which in which the distal portion of the article extends for between 0.25 and 0.33 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

[0109] Ex21 . An aerosol-generating article according to any preceding example in which the central portion of the article extends for between 0.1 and 0.6 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

[0110] Ex22. An aerosol-generating article according to Ex21 in which in which the central portion of the article extends for between 0.2 and 0.33 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

[0111] Ex23. An aerosol-generating article according to any preceding example in which an aerosol-forming substrate, for example an aerosol-forming material, is located within the airflow channel, preferably within the central portion of the airflow channel.

[0112] Ex24. An aerosol-generating article according to any preceding example in which an aerosol-forming substrate, for example an aerosol-forming material, forms part of one or more walls of the airflow channel.

[0113] Ex25. An aerosol-generating article according to any preceding example comprising: a first planar external surface; a second planar external surface; a cavity formed by the airflow channel; a frame positioned between the first planar external surface and the second planar external surface, the frame at least partially defining the cavity; one or more aerosol-generating substrates; and an air inlet and an air outlet, and an airflow passage extending between the air inlet and the air outlet through the cavity. Ex26. An aerosol-generating article according to Ex25, wherein a thickness of the aerosol-generating article is less than 33 percent of both a length and a width of the aerosolgenerating article.

[0114] Ex27. An aerosol-generating article according to Ex25 or Ex26, wherein the frame comprises a peripheral wall circumscribing or encircling the cavity.

[0115] Ex28. An aerosol-generating article according to Ex27, wherein the peripheral wall is formed by a frame inner surface and a frame outer surface, and wherein the frame inner surface defines a cavity outer wall, and the frame outer surface at least partially defines one or more external walls of the aerosol-generating article.

[0116] Ex29. An aerosol-generating article according to Ex27 or Ex28, wherein the peripheral wall has a radial thickness between 1 millimetre and 3.5 millimetres, for example about 3 millimetres.

[0117] Ex30. An aerosol-generating article according to any one of Ex25 to Ex29, wherein the frame has a thickness greater than or equal to 80 percent of the thickness of the aerosolgenerating article, for example between 80 percent and 95 percent of the thickness of the aerosolgenerating article.

[0118] Ex31. An aerosol-generating article according to any one of Ex25 to Ex30, wherein the frame has a thickness between 1 millimetre and 5.5 millimetres.

[0119] Ex32. An aerosol-generating article according to any one of Ex25 to Ex31 , wherein the air inlet is defined by the frame.

[0120] Ex33. An aerosol-generating article according to any one of Ex25 to Ex32, wherein the air inlet has an equivalent diameter between 0.1 millimetres and 3 millimetres.

[0121] Ex34. An aerosol-generating article according to any one of Ex25 to Ex33, wherein the air inlet has a width of between 0.3 millimetres and 5 millimetres, for example between 1 millimetres and 3 millimetres.

[0122] Ex35. An aerosol-generating article according to any one of Ex25 to Ex34, wherein the air inlet has a thickness of between 0.3 millimetres and 3 millimetres.

[0123] Ex36. An aerosol-generating article according to any one of Ex25 to Ex35, wherein the air outlet is defined by the frame.

[0124] Ex37. An aerosol-generating article according to any one of Ex25 to Ex36, wherein the air outlet has an equivalent diameter between 0.1 millimetres and 3 millimetres.

[0125] Ex38. An aerosol-generating article according to any one of Ex25 to Ex37, wherein the air outlet has a width of between 0.3 millimetres and 5 millimetres, for example between 1 millimetres and 3 millimetres.

[0126] Ex39. An aerosol-generating article according to any one of Ex25 to Ex38, wherein the air outlet has a thickness of between 0.3 millimetres and 3 millimetres. Ex40. An aerosol-generating article according to any one of Ex25 to Ex39, wherein a ratio between the length and the thickness of the aerosol-generating article, and between the width and the thickness of the aerosol-generating article is between 2:1 and 15:1.

[0127] Ex41. An aerosol-generating article according to any one of Ex25 to Ex40, wherein a ratio between the length and the width of the aerosol-generating article is between 1 :1 and 10:1.

[0128] Ex42. An aerosol-generating article according to any one of Ex25 to Ex41, wherein the aerosol-generating article has a length between 15 millimetres and 45 millimetres, for example between 25 millimetres and 35 millimetres, for example about 30 millimetres.

[0129] Ex43. An aerosol-generating article according to any one of Ex25 to Ex42, wherein the aerosol-generating article has a width between 3 millimetres and 17 millimetres, for example between 9 millimetres and 11 millimetres, for example about 10 millimetres.

[0130] Ex44. An aerosol-generating article according to any one of Ex25 to Ex43, wherein the aerosol-generating article has a thickness between 1 millimetres and 5.5 millimetres, for example between 3 millimetres and 3.5 millimetres, for example about 3.1 millimetres.

[0131] Ex45. An aerosol-generating article according to any one of Ex25 to Ex44, wherein the aerosol-generating article has resistance to draw between 0 millimetres H2O and 9.9 millimetres H2O.

[0132] Examples will now be further described with reference to the figures in which:

[0133] Figure 1 is a perspective side view of an aerosol-generating article according to a first embodiment of the present disclosure;

[0134] Figure 2 is a perspective side view of an aerosol-generating article according to a second embodiment of the present disclosure;

[0135] Figure 3 is a schematic end view of an aerosol-generating article according to a third embodiment of the present disclosure;

[0136] Figure 4 is a schematic side view of the aerosol-generating article of figure 3;

[0137] Figure 5 is a schematic plan view of the aerosol-generating article of figure 3;

[0138] Figure 6 shows a schematic illustration of a corrugated element as used in the aerosol-generating article of figure 3;

[0139] Figure 7 shows a perspective view of an aerosol-generating article according to a fourth embodiment of the present disclosure;

[0140] Figure 8 shows an exploded perspective view of the aerosol-generating article of figure 7; Figure 9 shows a further exploded perspective view of the aerosol-generating article of figure 7;

[0141] Figure 10 shows a schematic transverse cross-sectional view of the aerosol-generating article of figure 7;

[0142] Figure 11 shows a schematic longitudinal cross-sectional view of the aerosol-generating article of figure 7;

[0143] Figure 12 shows an exploded perspective view of an aerosol-generating article according to a fifth embodiment of the present disclosure;

[0144] Figure 13 shows a schematic transverse cross-sectional view of the aerosol-generating article of figure 12;

[0145] Figure 14 shows a schematic lateral cross-sectional view of the aerosol-generating article of figure 12.

[0146] Figure 15 shows a schematic view of an aerosol-generating device according to an embodiment of the present disclosure, the device configured to engage with an aerosolgenerating article, for example the aerosol-generating article of any of figures 1 to 14;

[0147] Figure 16 shows a schematic end view of the aerosol-generating device of figure 15;

[0148] Figure 17 is a schematic view showing an aerosol-generating article (for example, the aerosol-generating article of any of figures 1 to 14) in engagement with the aerosol-generating device of figure 15.

[0149] Figure 18 is a schematic view of an alternative embodiment to that of figures 15 to 17, showing an aerosol-generating article in engagement with an aerosol-generating device.

[0150] Figure 19 shows a perspective view of an aerosol-generating article according to the present disclosure;

[0151] Figure 20 shows an exploded perspective view of the aerosol-generating article of Figure 19;

[0152] Figure 21 shows an exploded perspective view of an aerosol-generating article according to the present disclosure;

[0153] Figure 22 shows a plan view of an aerosol-generating article according to the present disclosure, showing a cavity having a laterally divergent proximal portion and a laterally convergent distal portion;

[0154] Figure 23 shows a plan view of an aerosol-generating article according to the present disclosure, showing a cavity having a laterally divergent proximal portion and a laterally convergent distal portion; and

[0155] Figure 24 shows a further plan view of the aerosol-generating article of Figure 23.

[0156] Figure 1 illustrates a perspective side view of an aerosol-generating article 100 according to a first embodiment of the present disclosure. The aerosol-generating article 100 has upper and lower surfaces 110, 120 which are flat or planar. The aerosol-generating article 100 comprises an aerosol-forming substrate (not shown). In one embodiment, the aerosol-generating article 100 may consist substantially of aerosol-forming substrate. In another embodiment, the aerosol-forming substrate may be one of a plurality of component parts of the aerosol-generating article 100. The aerosolforming substrate may be enclosed within an interior of the aerosol-generating article 100. The aerosol-forming substrate may at least partially define an exterior of the aerosolgenerating article 100; for example, one or both of the upper and lower surfaces 110, 120 may comprise or consist of aerosol-forming substrate.

[0157] A suitable aerosol-forming substrate may be homogenised tobacco.

[0158] The aerosol-generating article 100 has a length, extending in an x dimension, of 80 millimetres, a width, extending in a y dimension, of 15 millimetres, and a height (which may also be referred to as a thickness), extending in a z dimension, of 3.6 millimetres.

[0159] Figure 2 illustrates a perspective side view of an aerosol-generating article 200 according to a second embodiment of the present disclosure, being a variant of aerosolgenerating article 100. Features in common with aerosol-generating article 100 are referred to with like reference signs but commencing with numeral 2 instead of numeral 1 . An air flow path 230 is defined through the aerosol-generating article 200 between the upper and lower surfaces 210, 220. The air flow path 230 extends between opposed first and second ends 201 , 202 of the aerosol-generating article 200. The first end 201 may define a distal end of the aerosol-generating article 200, and the second end 202 may define a proximal or mouth end of the aerosol-generating article. The air flow path 230 may be directed towards a mouth of a user to allow a user to inhale aerosol generated in consequence of heating of aerosol-forming substrate of the aerosol-generating article 200.

[0160] Figures 3, 4, and 5 illustrate respectively an end view, a side view, and a plan view of an aerosol-generating article 300 according to a third embodiment of the present disclosure. The aerosol-generating article 300 comprises a planar upper layer 310, a planar lower layer 320, and an intermediate or separation layer 340 arranged between the upper layer 310 and lower layer 320.

[0161] The planar upper layer 310 is formed from a sheet of paper having a thickness of 300 microns. The planar lower layer 320 is formed from a sheet of paper having a thickness of 300 microns. The intermediate layer 340 is a corrugated element formed from a corrugated sheet of aerosol-forming substrate 345. A suitable aerosol-forming substrate may be homogenised tobacco. Thus, the intermediate layer 340 may be formed from a corrugated sheet of homogenised tobacco material 345.

[0162] Figure 6 illustrates the corrugated sheet of aerosol-forming substrate 345. The corrugations have an amplitude 346 of 3 millimetres and a wavelength 347 of 3 millimetres. The sheet of aerosol-forming substrate 345 forming the intermediate layer 340 has a thickness of 150 microns. Points of intersection 351 , 352 between the upper layer 310 and the intermediate layer 340 and between the lower layer 320 and the intermediate layer 340 comprise an adhesive that joins the respective layers.

[0163] The aerosol-generating article 300 has a length, extending in an x dimension, of 80 millimetres, a width, extending in a y dimension, of 15 millimetres, and a height (or thickness), extending in a z dimension, of 3.6 millimetres.

[0164] Corrugations of the intermediate layer 340 form a first set of longitudinally extending channels 361 that are bounded by the upper layer 310 and the intermediate layer 340, and a second set of longitudinally extending channels 362 bounded by the lower layer 320 and the intermediate layer 340. The first and second sets of longitudinally extending channels 361 , 362 extend through the length of the aerosol-forming substrate between a proximal end 371 of the substrate 345 and a distal end 372 of the substrate 345. The longitudinally extending channels 361 , 362 define an air-flow path through the substrate 345. The air-flow path, therefore, passes over both sides of the sheet of aerosol-forming substrate 345. The porosity of the aerosolgenerating article along the air-flow path is in the region of 90 %. This provides a very low resistance to draw (RTD) of less than 5 mm H2O. In fact, the RTD is close to zero.

[0165] The aerosol-forming substrate 345 may be a sheet of any suitable aerosol-forming substrate.

[0166] During use of the aerosol-generating article 300, the aerosol-forming substrate 345 is heated up to cause the aerosol-forming substrate 345 to release volatile compounds, which are then entrained in air drawn into the channels 361 , 362 via the distal end 372. The volatile compounds then cool and condense to form an aerosol which may be drawn out of the channels 361 , 362 of the aerosol-generating article 300 via the proximal end 371 .

[0167] Figure 7 shows an aerosol-generating article 400 according to a fourth embodiment of the present disclosure. The aerosol-generating article 400 comprises a first planar external layer 424 forming a first planar external surface 421 , a second planar external layer 425 forming a second planar external surface 422, and a frame 450 positioned between the first planar external layer 424 and the second planar external layer 425. The second planar external surface 422 is positioned parallel to the first planar external surface 421.

[0168] Figures 8 and 9 show exploded views of the aerosol-generating article 400 of figure 7. The frame 450 circumscribes and at least partially defines a cavity 430. Figure 8 shows the cavity 430 in an empty state. Figure 9 shows the cavity 430 filled with aerosol-forming substrate 440. Figures 10 and 11 show respective transverse and longitudinal cross-sectional views of the aerosol-generating article 400 when the cavity 430 is filled with aerosol-forming substrate 440.

[0169] The first planar external layer 424 and the second planar external layer 425 are made from cigarette paper having a thickness of 35 micrometres and are in physical contact, with and bonded to, the frame 450. The first planar external layer 424 overlies a first end of the cavity 430 and forms a first cavity end wall 431. The second planar external layer 425 overlies a second end of the cavity 430 and forms a second cavity end wall 432, the second cavity end wall 432 being opposite to the first cavity end wall 431. That is, the frame 450, the first planar external layer 424 and the second planar external layer 425 collectively define the cavity 430.

[0170] The frame 450 has a hollow cuboid shape and is made from cardboard. The frame 450 defines an aperture extending through the height (also referred to as the thickness) of the frame 450 and the aperture at least partially forms the cavity 430 of the aerosolgenerating article 400. The frame 450 comprises a peripheral wall 451 that circumscribes the cavity 430. The peripheral wall 451 includes a front wall 413 and a back wall 414. In more detail, the peripheral wall 451 is defined by an inner transverse surface 452 of the frame 450 and an outer transverse surface 453 of the frame 450. The inner transverse surface 452 of the peripheral wall 451 at least partially defines a perimeter of the cavity 430. The outer transverse surface 453 of the peripheral wall 451 at least partially defines a perimeter of the aerosol-generating article 400. The peripheral wall 451 has a radial thickness measured between the inner transverse surface 452 of the frame 450 and the outer transverse surface 453 of the frame 450 of about 5 millimetres.

[0171] An air inlet 411 and an air outlet 412 are defined by, and extend through, the peripheral wall 451 of the frame 450. More specifically, the air inlet 411 extends through the front wall 413 and the air outlet 412 extends through the back wall 414. The air inlet 411 and the air outlet 412 have an equivalent diameterof 5 millimetres. An airflow passage extends between the air inlet 411 and the air outlet 412 through the cavity 430. As shown in figures 9 to 11 , an aerosol-forming substrate 440 is positioned within the cavity 430. The aerosol-forming substrate 440 comprises an aerosol-generating material in the form of tobacco cut filler and has an aerosol-former content of 5 percent by weight on a dry weight basis. As shown, the aerosol-forming substrate 440 fills the entire volume of the cavity 430.

[0172] The aerosol-generating article 400 has a cuboid shape and has a height (or thickness) extending in a z dimension, as measured between the first planar external surface 421 and the second planar external surface 422, of 8 millimetres, a width extending in a y dimension of 40 millimetres and a length extending in an x dimension of 60 millimetres. The frame 450 has a height (or thickness) extending in a z dimension of 7.93 millimetres, a width extending in a y dimension of 40 millimetres and a length extending in an x dimension of 60 millimetres. The cavity 430 has a height (or thickness) extending in a z dimension of 7.93 millimetres, a width extending in a y dimension of 30 millimetres and a length extending in an x dimension of 50 millimetres.

[0173] Figure 12 shows an aerosol-generating article 500 according to a fifth embodiment of the present disclosure. Features in common with aerosol-generating article 400 are referred to with like reference signs but commencing with numeral 5 instead of numeral 4. Aerosol-generating article 500 differs from aerosol-generating article 400 in that the aerosol-forming substrate is in the form of a sheet of aerosol-generating material 540, in particular a corrugated sheet of homogenised tobacco material. Figures 13 and 14 show respective transverse and lateral cross-section views of the aerosol-generating article 500 of figure 12.

[0174] The corrugated sheet of homogenised tobacco material 540 comprises a plurality of parallel corrugations having a plurality of substantially parallel peaks 543 and troughs 544. The plurality of parallel corrugations are defined by a corrugation profile which, as seen in figure 13, is sinusoidal. The plurality of parallel corrugations have a corrugation wavelength of about 4.6 millimetres. The corrugation amplitude is approximately the same as the height (or thickness) of the cavity 430, as shown by the peaks 543 and troughs 544 coinciding with the first cavity end wall 531 and the second cavity end wall 532, respectively.

[0175] The plurality of parallel corrugations form a plurality of channels 545 between the sheet of aerosol-generating material 540 and the first cavity end wall 531 , and a plurality of channels 546 between the sheet of aerosol-generating material 540 and the second cavity end wall 532. The plurality of channels 545, 546 extend in a longitudinal direction of the aerosol-generating article 500 and form at least a portion of the airflow passage extending between the air inlet 511 and the air outlet 512.

[0176] During use of each of the aerosol-generating articles 400, 500, the aerosol-forming substrate 440, 540 is heated up to cause the aerosol-forming substrate 440, 540 to release volatile compounds, which are then entrained in air drawn through the air inlet 411 , 511 into the cavity 430, 530. The volatile compounds then cool and condense to form an aerosol which may be drawn out of the aerosol-generating article 400, 500 through the air outlet 412, 512.

[0177] Figures 15 and 16 illustrate an aerosol-generating device 6000 configured for use with an aerosol-generating article 600 comprising or consisting of aerosol-forming substrate 640. The device 6000 is an elongate aerosol-generating device extending between a proximal end 6001 and a distal end 6002. The device 6000 comprises a battery 6010, a controller 6020 and a heater 6030 located within a housing 6040. The controller 6020 controls supply of power from the battery 6010 to the heater 6030. A cavity 6050 is defined in the device 6000, the cavity having an opening 6051 defined in the proximal end 6001 of the device. The opening 6051 is rectangular in shape and is dimensioned to accommodate the transverse cross-section of the aerosol-generating article 600. The cavity 6050 comprises an upper planar surface 6052 and a lower planar surface 6053. The heater 6030 is located in the lower planar surface 6053 to heat a lower surface of the aerosol-generating article 600 inserted into the cavity 6050. An air-flow path is configured to allow air to flow into the cavity 6050 from outside the device 6000.

[0178] Figure 17 illustrates the device 6000 of figure 15 in engagement with the aerosolgenerating article 600. There is little tolerance between outer surfaces of the aerosol-generating article 600 and the internal surfaces of the cavity 6050. Thus, there is a snug fit between the aerosol-generating article 600 and the device 6000. As the RTD of the aerosol-generating article 600 is negligible, the RTD of the system formed by the combination of aerosolgenerating article 600 and aerosol-generating device 6000 is controlled by the air-flow path defined within the device. When a user has inserted the aerosol-generating article 600 into the cavity 6050, the device 6000 can be operated. The heater 6030 heats a lower surface of the aerosol-generating article 600, and as a result the aerosol-forming substrate 640 of the aerosol-generating article 600 is heated. Volatile components of the aerosolforming substrate 640 are evaporated and condense in longitudinal air-flow channels defined within the aerosol-generating article 600 to form an aerosol. The user inhales the aerosol by drawing on the proximal end 601 of the aerosol-generating article 600. Once the aerosol-generating substrate 640 of the aerosol-generating article 600 has been depleted of volatile components, the aerosol-generating article is removed from the cavity 6050 of the device 6000 and disposed of. The aerosol-generating article 600 may be any one of the aerosol-generating articles 100, 200, 300, 400, 500 previously described or any other aerosol-generating article of the present disclosure.

[0179] Although figure 17 shows part of the aerosol-generating article 600 extending outside of the aerosol-generating device 6000, in other embodiments the entirety of an aerosol-generating article may be wholly enclosed within an aerosol-generating device. By way of example, figure 18 illustrates an alternative embodiment to that of figure 17, with like features referred to by the same reference numbers but with the addition of a prime symbol ’. For the alternative embodiment of figure 18, the entirety of aerosolgenerating article 600’ is enclosed within the interior of aerosol-generating device 6000’.

[0180] Figure 19 shows an aerosol-generating article 1910 comprising a first planar external layer 1924 forming a first planar external surface 1921 , a second planar external layer 1925 forming a second planar external surface 1922, and a frame 1950 positioned between the first planar external layer 1924 and the second planar external layer 1925. The first planar external layer 1924 and the second planar external layer 1925 both comprise an aerosol-generating substrate comprising an aerosol-generating material, namely tobacco. However, it will be understood that in some embodiments only one of the first planar external layer 1924 and the second planar external layer 1925 may comprise an aerosol-generating substrate. Alternatively, or additionally, the aerosol-generating substrate may be positioned elsewhere within the aerosol-generating article 1910.

[0181] The aerosol-generating article 1910 has a length extending in the x-direction, a width extending in the y-direction and a thickness extending in the z-direction. The aerosol-generating article 1910 has a length of 30 millimetres, a width of 10 millimetres, and a thickness of 3.1 millimetres.

[0182] The aerosol-generating article 1910 is a substantially flat aerosol-generating article or substantially planar aerosol-generating article. In particular, the thickness of the aerosol-generating article 1910 is less than 50 percent of both the length and the width of the aerosol-generating article. The aerosol-generating article 1910 has a generally rectangular cuboid shape and a laminated structure formed by the first planar external layer 1924, the frame 1950 and the second planar external layer 1925. The first planar external layer 1924, the frame 1950 and the second planar external layer 1925 are bonded together with an adhesive, in particular guar gum, as discussed in more detail below in relation to Figure 20.

[0183] Figure 20 shows an exploded view of the aerosol-generating article 1910 of Figure 19.

[0184] The frame 1950 has a length of 30 millimetres, a width of 10 millimetres, and a thickness of 2.7 millimetres. The frame 1950 is made from cardboard and defines a frame aperture extending through the thickness of the frame 1950. The frame aperture at least partially forms a cavity 1930. The cavity 1930 has length of 26 millimetres, a width of 6 millimetres, and a thickness of 2.7 millimetres. The cavity 1930 is formed by an airflow channel extending through the article.

[0185] The frame 1950 has a frame inner surface 1952 extending in the z-direction or the transverse direction between the first planar external surface 1921 and the second planar external surface 1922. The frame inner surface 1952 defines a cavity outer wall. The frame 1950 has a frame outer surface 1953 extending in the z-direction or the transverse direction between the first planar external surface 1921 and the second planar external surface 1922. The frame outer surface 1953 at least partially defines one or more external surfaces of the aerosol-generating article, such as the front wall 1913 and the back wall 1914.

[0186] The frame 1950 comprises a peripheral wall 1951 that circumscribes the cavity 1930. In more detail, the peripheral wall 1951 is defined by the frame inner surface 1952 and the frame outer surface 1953.

[0187] The cavity 1930 comprises a parallel section 1931 and a converging section 1932. The converging section 1932 has decreasing width from a first end of the converging section 1932 to the second end of the converging section 1932. The converging section 1932 forms a distal portion of the cavity or airflow channel 1930.

[0188] The peripheral wall 1951 comprises the front wall 1913 and the back wall 1914. The parallel section 1931 extends from the front wall 1913 to the converging section 1932. The converging section 1932 extends from the parallel section 1931 to the back wall 1914. As such, the converging section 1932 is located downstream of the parallel section. During use of the aerosol-generating article 1910, air is drawn into the article through an air inlet 1911 of the aerosol-generating article 1910, then through the parallel section 1931 of the cavity 1930, then through the distal converging section 1932 of the cavity 1930 and then out of the aerosolgenerating article 1910 through an air outlet 1912 of the aerosol-generating article 1910.

[0189] The peripheral wall 1951 comprises a first side wall and an opposing second side wall 1962. The front wall 1913, back wall 1914, first side wall 1961 , and second side wall together define the perimeter of the cavity. The first side wall comprises a first parallel side wall portion 1961 and a first converging side wall portion 1971. The first parallel side wall portion 1961 extends from the front wall 1913 to first end of the first converging side wall portion 1971 . The first converging side wall portion 1971 extends from second end of the first parallel side wall portion 1961 to the back wall 1914. The second side wall comprises a second parallel side wall portion 1962 and a second converging side wall portion 1972. The second parallel side wall portion 1962 extends from the front wall 1913 to the first end of the second converging side wall portion 1972. The second converging side wall portion 1972 extends from the second end of the second parallel side wall portion 1971 to the back wall 1914.

[0190] Both of the first converging side wall portion 1971 and the second converging side wall portion 1972 have increasing width from the first end of the converging section 1932 to the second end of the converging section 1932. This may provide the aerosolgenerating article 1910 with structural rigidity.

[0191] The external surface of both the first converging side wall portion 1971 and the second converging side wall portion 1972 are parallel to the x-direction.

[0192] The converging section 1932 has a length of 13 millimetres, a width at the first end of the converging section 1932 of 6 millimetres, a width at the second end of the converging section 1932 of 3 millimetres, and a thickness of 2.7 millimetres. Accordingly, the length of the converging section 1932 is greater than the width of the converging section 1932 at the first end of the converging section 1932.

[0193] The parallel section 1932 has a length of 13 millimetres, a constant width along the entire length of the parallel section 1932 of 6 millimetres of 2.7 millimetres.

[0194] The first planar external layer 1924 and the second planar external layer 1925 have a thickness of 200 micrometres and are in physical contact with the frame 1950. The first planar external layer 1924 and the second planar external layer 1925 are bonded to the frame with an adhesive 1915. The first planar external layer 1924 defines at least a portion of the cavity 1930. The second planar external layer 1925 defines at least a portion of the cavity 1930.

[0195] The air inlet 1911 and the air outlet 1912 are defined by, and extend through, the peripheral wall 1951 of the frame 1950. The air inlet 1911 and the air outlet 1912 each have a rectangular cross-section, a width of 3 millimetres, and a thickness of 0.9 millimetres. An airflow passage extends between the air inlet 1911 and the air outlet 1912 through the cavity 1930.

[0196] Figure 21 shows an exploded view of an aerosol-generating article 2010 that is similar to the aerosol-generating article 1910 of Figure 1 except that the first planar external layer 2024 and the second planar external layer 2025 do not comprise an aerosolgenerating substrate. Instead, an aerosol-generating substrate 2040 is positioned within the parallel section 3201 of the cavity 2030. The aerosol-generating substrate 2040 comprises an aerosol-generating material in the form of tobacco cut filler and has an aerosol-former content of 5 percent by weight on a dry weight basis. The tobacco cut filler may be wrapped in a wrapper. As shown, the aerosol-generating substrate 2040 fills the entire volume of the parallel section 2031 of the cavity 2030. In the example of Figure 21 , the aerosolgenerating substrate 2040 has a packing density of about 0.87, a density of about 0.3 grams per cubic centimetre, and a mass of about 55 milligrams. In another example, the aerosol-generating substrate 2040 may have a different packing density, a different density and a different mass. For example, aerosol-generating substrate may have a packing density of 0.64, a density of 0.35 grams per cubic centimetre, and a mass of about 47 milligrams.

[0197] The converging section 2032 of the cavity 2030 is empty. In particular, the aerosolgenerating substrate 2040 does not extend into the converging section 32 of the cavity 2030.

[0198] The aerosol-generating articles of Figures 19 to 21 have a cavity defined within an airflow channel that has a distal portion that converges laterally from a central portion of the cavity to an air outlet. Other embodiments of aerosol-generating articles may additionally have a proximal portion of the cavity that diverges from an air inlet towards the central portion of the cavity. A plan view of such an aerosol generating article 2210 is illustrated in Figure 22. The aerosol-generating article 2210 of Figure 22 is substantially the same as the article described in relation to figures 19 and 20 and has a cavity comprising a parallel sided central portion 2230 and a laterally converging distal portion 2231. The aerosol-generating article 2210 additionally comprises a laterally diverging proximal portion 2232. A cavity that has a laterally diverging proximal portion as well as a laterally converging distal portion may further reduce turbulence of airflow passing through the article.

[0199] Figures 23 and 24 illustrate plan views of a further aerosol-generating article 2310 showing the profile of the internal airflow channel or cavity 2330. The cavity 2330 comprises a proximal portion 2301 in which the cavity laterally diverges towards a central portion 2302, and a distal portion 2303 in which the cavity laterally converges from the central portion 2302. A left lateral side wall 2311 , 2312 and a right lateral sidewall 2315, 2316 have a sinusoidal profile. The aerosolgenerating article is symmetrical about a lateral centre axis (line A-A in Figure 23) and a longitudinal centre axis (line B-B in Figure 23). Furthermore, a proximal portion of the right lateral wall 2315 conforms in shape to a distal portion of the left lateral wall 2312 and a proximal portion of the left lateral wall 2311 conforms in shape to a distal portion of the right lateral wall 2316. Such a shape may provide manufacturing benefits.

[0200] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number “A” is understood as “A” ± 10% of “A”. Within this context, a number “A” may be considered to include numerical values that are within general standard error for the measurement of the property that the number “A” modifies. The number “A”, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which “A” deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. The terms “in which” and “wherein” are used synonymously through this specification.

Claims

CLAIMS1. An aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article defined by a first planar dimension, a second planar dimension, and a thickness, in which both the first planar dimension and the second planar dimension are at least three times the magnitude of the thickness, in which an airflow channel is defined through the aerosol-generating article between an airflow inlet and an airflow outlet, and in which a proximal portion of the airflow channel diverges laterally between the airflow inlet and a central portion of the airflow channel, and a distal portion of the airflow channel converges laterally between the central portion of the airflow channel to the airflow outlet.

2. An aerosol-generating article according to claim 1 in which the first planar dimension is a length and the second planar dimension is a width, in which the airflow channel extends longitudinally in the first planar dimension between the air inlet and the air outlet, for example in which the air inlet is defined in a first end face of the article and the air outlet is defined in a second end face of the article.

3. An aerosol-generating article according to any preceding claim in which the article comprises an upper surface, a lower surface, a first end face, a second end face, a first side face and a second side face, and an airflow path is defined through the article between the upper surface and the lower surface, the airflow path defined by the airflow channel extending between the airflow inlet and the airflow outlet.

4. An aerosol-generating article according to any preceding claim, in which the airflow channel is defined by a left lateral wall extending from a left side of the air inlet to a left side of the air outlet, and a right lateral wall extending from a right side of the air inlet to a right side of the air outlet.

5. An aerosol-generating article according to claim 4 in which one, or both, of the left lateral wall and the right lateral wall comprises a proximal portion that diverges away from a lateral centre line of the article and a distal portion that converges towards the lateral centre line of the article.

6. An aerosol-generating article according to claim 4 or 5 in which the left lateral wall, and / or the right lateral wall, is substantially trapezoidal in shape.

7. An aerosol-generating article according to claim 4 or 5 in which the left lateral wall, and / or the right lateral wall, is substantially curved in shape, for example in which the left lateral wall, and / or the right lateral wall, is sinusoidal in shape.

8. An aerosol-generating article according to any preceding claim in which the shape of the airflow channel is symmetrical with respect to a longitudinal centre axis, and / or symmetrical with respect to a lateral centre axis.

9. An aerosol-generating article according to any preceding claim in which the shape of a proximal portion of a left lateral wall conforms to the shape of a distal portion of aright lateral wall, and the which the shape of a proximal portion of the right lateral wall conforms to the shape of a distal portion of the left lateral wall.

10. An aerosol-generating article according to any preceding claim in which the proximal portion of the article extends for between 0.2 and 0.5 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension, preferably in which in which the proximal portion of the article extends for between 0.25 and 0.33 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

11. An aerosol-generating article according to any preceding claim in which the distal portion of the article extends for between 0.2 and 0.5 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension, preferably in which the distal portion of the article extends for between 0.25 and 0.33 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

12. An aerosol-generating article according to any preceding claim in which the central portion of the article extends for between 0.1 and 0.6 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension, preferably in which the central portion of the article extends for between 0.2 and 0.33 of the distance between the air inlet and the air outlet, for example the distance along the first planar dimension or the distance along the second planar dimension.

13. An aerosol-generating article according to any preceding claim in which an aerosol-forming substrate, for example an aerosol-forming material, is located within the airflow channel, preferably within the central portion of the airflow channel.

14. An aerosol-generating article according to claim 13 in which the aerosolforming substrate comprises or consists of cut filler tobacco or beads of tobacco.

15. An aerosol-generating article according to any preceding claim in which an aerosol-forming substrate, for example an aerosol-forming material, forms part of one or more walls of the airflow channel.

Images