Aerosol-generating article

Abstract

An aerosol-generating article (100) for use with an aerosol-generating device (6000) to generate an aerosol, the aerosol-generating article (100) comprising: a first external surface (110); a second external surface (120); a cavity defined between the first external surface (110) and the second external surface (120); and one or more air outlets (112), wherein at least one of the one or more air outlets (112) has a cross-sectional area of less than 0.3 square millimetres.

Description

[0001] AEROSOL-GENERATING ARTICLE

[0002] The present disclosure relates to an aerosol-generating article. The present disclosure also relates to an aerosol-generating device for use with the aerosol-generating article. The present disclosure also relates to an aerosol-generating system comprising the aerosol-generating device and the aerosol-generating article.

[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 is provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol. The aerosol-generating article may comprise a first external surface. The aerosol-generating article may comprise a second external surface. The aerosol-generating article may comprise a cavity defined between the first external surface and the second external surface. The aerosol-generating article may comprise one or more air outlets. At least one of the one or more air outlets may have a cross-sectional area of less than or equal to 0.3 square millimetres.

[0007] According to the present disclosure, there is provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising: a first external surface; a second external surface; a cavity defined between the first external surface and the second external surface; and one or more air outlets, wherein at least one of the one or more air outlets has a cross-sectional area of less than or equal to 0.3 square millimetres.

[0008] According to the present disclosure, there is provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol. The aerosol-generating article may comprise a first external surface. The aerosol-generating article may comprise a second external surface. The aerosol-generating article may comprise a cavity defined between the first external surface and the second external surface. The aerosol-generating article may comprise one or more air inlets. At least one of the one or more air inlets may have a cross-sectional area of less than or equal to 0.3 square millimetres.

[0009] According to the present disclosure, there is provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising: a first external surface; a second external surface; a cavity defined between the first external surface and the second external surface; and one or more air inlets, wherein at least one of the one or more air inlets has a cross-sectional area of less than or equal to 0.3 square millimetres.

[0010] Advantageously, the provision of a relatively small air outlet may help to improve the mechanical strength of the aerosol-generating article at the air outlet. Improving the mechanical strength of the aerosol-generating article at the air outlet may provide for better manufacturing. For example, the air outlet may have improved resistance to collapsing during the manufacturing process.

[0011] Advantageously, the provision of a relatively small air outlet may allow for reducing the likelihood of aerosol-generating substrate within the cavity falling out of the cavity through the air outlet. Reducing the likelihood of aerosol-generating substrate falling out of the cavity may provide for a longer user experience.

[0012] Advantageously, the provision of a relatively small air outlet may reduce waste because a smaller portion of the aerosol-generating article is removed to form the air outlet during the process of manufacturing the aerosol-generating article.

[0013] Advantageously, the provision of a relatively small air inlet may help to improve the mechanical strength of the aerosol-generating article at the air inlet. Improving the mechanical strength of the aerosol-generating article at the air inlet may provide for better manufacturing. For example, the air inlet may have improved resistance to collapsing during the manufacturing process.

[0014] Advantageously, the provision of a relatively small air inlet may allow for reducing the likelihood of aerosol-generating substrate within the cavity falling out of the cavity through the air inlet. Reducing the likelihood of aerosol-generating substrate falling out of the cavity may provide for a longer user experience. Advantageously, the provision of a relatively small air inlet may reduce waste because a smaller portion of the aerosol-generating article is removed to form the air inlet during the process of manufacturing the aerosol-generating article.

[0015] The height of the aerosol-generating article may be less than both of the length and width of the aerosol-generating article. For the purpose of the present disclosure, the “height” of the aerosol-generating article may also be referred to as the “thickness” of the aerosol-generating article.

[0016] 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.

[0017] 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.

[0018] 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%.

[0019] 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 airflow 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.

[0020] 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 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.

[0021] 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.

[0022] According to the present disclosure, there may be provided an aerosol-generating article for use with an aerosol-generating device to generate an aerosol.

[0023] The aerosol-generating article may comprise a frame. The frame may be positioned between the first external surface and the second external surface. The frame may at least partially define the cavity.

[0024] At least one of the first external surface and the second external surface may be a planar surface. The first external surface may be a first planar external surface. The second external surface may be a second planar external surface. The first external surface may be a first planar external surface and the second external surface may be a second planar external surface.

[0025] The aerosol-generating article may comprise one or more aerosol-forming substrates. The aerosol-generating article may comprise an air inlet and an air outlet, and an airflow passage extending between the air inlet and the air outlet through the cavity. Preferably, an aerosol-forming substrate is positioned between the first planar external surface and the second planar external surface.

[0026] 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.

[0027] 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.

[0028] The cavity may be substantially empty.

[0029] Aerosol-forming substrate may be positioned within the cavity.

[0030] A corrugated layer may be positioned within the cavity.

[0031] The frame may be a planar frame.

[0032] 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.

[0033] 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.

[0034] The frame may be made from or comprise a biodegradable material. The frame may be made entirely from a biodegradable material.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] The aerosol-generating article may have a width (for example, a y dimension) of between

[0039] 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.

[0040] 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

[0041] 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.

[0042] 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 ora square), an oval, a circle, or a combination thereof. Where the aerosol-generating 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.

[0043] The aerosol-generating article may comprise one or more air outlets.

[0044] The one or more air outlets may comprise a single air outlet. In other words, the aerosolgenerating article may comprise a single air outlet.

[0045] The one or more air outlets may comprise a plurality of air outlets. In other words, the aerosol-generating article may comprise a plurality of air outlets.

[0046] At least one of the one of more air outlets may extend through the first external surface. Each of the one of more air outlets may extend through the first external surface. Each of the plurality of air outlets may extend through the first external surface.

[0047] At least one of the one of more air outlets may extend through the second external surface. Each of the one of more air outlets may extend through the second external surface. Each of the plurality of air outlets may extend through the second external surface.

[0048] At least one of the one or more air outlets may extend through the frame. Each of the one or more air outlets may extend through the frame. Each of the plurality of air outlets may extend through the frame. At least one of the one or more air outlets may extend through the peripheral wall of the frame. Each of the one or more air outlets may extend through the peripheral wall of the frame. Each of the plurality of air outlets may extend through the peripheral wall of the frame.

[0049] At least one of the one or more air outlets may extend through the peripheral frame and at least one of the one or more air outlets and extend through the first external surface.

[0050] At least one of the one or more air outlets may extend through the peripheral frame and at least one of the one or more air outlets and extend through the second external surface.

[0051] The aerosol-generating article may comprise one or more air inlets.

[0052] The one or more air inlets may comprise a single air inlet. In other words, the aerosolgenerating article may comprise a single air inlet.

[0053] The one or more air inlets may comprise a plurality of air inlets. In other words, the aerosolgenerating article may comprise a plurality of air inlets.

[0054] At least one of the one of more air inlets may extend through the first external surface. Each of the one of more air inlets may extend through the first external surface. Each of the plurality of air inlets may extend through the first external surface.

[0055] At least one of the one of more air inlets may extend through the second external surface. Each of the one of more air inlets may extend through the second external surface. Each of the plurality of air inlets may extend through the second external surface.

[0056] At least one of the one or more air inlets may extend through the frame. Each of the one or more air inlets may extend through the frame. Each of the plurality of air inlets may extend through the frame.

[0057] At least one of the one or more air inlets may extend through the peripheral wall of the frame. Each of the one or more air inlets may extend through the peripheral wall of the frame. Each of the plurality of air inlets may extend through the peripheral wall of the frame.

[0058] At least one of the one or more air inlets may extend through the peripheral frame and at least one of the one or more air inlets and extend through the first external surface.

[0059] At least one of the one or more air inlets may extend through the peripheral frame and at least one of the one or more air inlets and extend through the second external surface.

[0060] The aerosol-generating article may comprise an element positioned within at least one of the one or more air inlets. The aerosol-generating article may comprise an element positioned within each of the one or more air inlets.

[0061] The aerosol-generating article may comprise an element positioned within at least one of the one or more air outlets. The aerosol-generating article may comprise an element positioned within each of the one or more air outlets.

[0062] The element may be a porous element. The element may be a filter element.

[0063] The element may comprise at least one corrugation. The element may comprise a plurality of corrugations. The at least one corrugation may extend in the longitudinal direction. The plurality of corrugations may extend in the longitudinal direction.

[0064] The at least one corrugation may comprise at least one corrugation arranged within the air inlet and at least one corrugation arranged in the air outlet.

[0065] At least one of the one or more air outlets may have a cross-sectional area of less than 0.5 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of less than 0.45 square millimetres. At least one of the one or more air outlets may have a cross- sectional area of less than 0.4 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of less than 0.35 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of less than 0.3 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of less than 0.25 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of less than 0.2 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of less than 0.15 square millimetres.

[0066] At least one of the one or more air outlets may have a cross-sectional area of greater than or equal to 0.01 square millimetres. At least one of the one or more air outlets may have a cross- sectional area of greater than or equal to 0.05 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of greater than or equal to 0.1 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of greater than or equal to 0.15 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of greater than or equal to 0.2 square millimetres.

[0067] At least one of the one or more air outlets may have a cross-sectional area of between 0.05 square millimetres and 0.5 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of between 0.1 square millimetres and 0.45 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of between 0.15 square millimetres and 0.4 square millimetres. At least one of the one or more air outlets may have a cross-sectional area of between 0.2 square millimetres and 0.35 square millimetres.

[0068] Each of the one or more air outlets may have a cross-sectional area of less than 0.5 square millimetres. Each of the one or more air outlets may have a cross-sectional area of less than 0.45 square millimetres. Each of the one or more air outlets may have a cross-sectional area of less than 0.4 square millimetres. Each of the one or more air outlets may have a cross-sectional area of less than 0.35 square millimetres. Each of the one or more air outlets may have a cross-sectional area of less than 0.3 square millimetres. Each of the one or more air outlets may have a cross- sectional area of less than 0.25 square millimetres. Each of the one or more air outlets may have a cross-sectional area of less than 0.2 square millimetres. Each of the one or more air outlets may have a cross-sectional area of less than 0.2 square millimetres.

[0069] Each of the one or more air outlets may have a cross-sectional area of greater than or equal to 0.01 square millimetres. Each of the one or more air outlets may have a cross-sectional area of greater than or equal to 0.05 square millimetres. Each of the one or more air outlets may have a cross-sectional area of greater than or equal to 0.1 square millimetres. Each of the one or more air outlets may have a cross-sectional area of greater than or equal to 0.15 square millimetres. Each of the one or more air outlets may have a cross-sectional area of greater than or equal to 0.2 square millimetres.

[0070] Each of the one or more air outlets may have a cross-sectional area of between 0.05 square millimetres and 0.5 square millimetres. Each of the one or more air outlets may have a cross-sectional area of between 0.1 square millimetres and 0.45 square millimetres. Each of the one or more air outlets may have a cross-sectional area of between 0.15 square millimetres and 0.4 square millimetres. Each of the one or more air outlets may have a cross-sectional area of between 0.2 square millimetres and 0.35 square millimetres.

[0071] The air outlet may have a total cross-sectional area of less than 0.5 square millimetres. The air outlet may have a total cross-sectional area of less than 0.45 square millimetres. The air outlet may have a total cross-sectional area of less than 0.4 square millimetres. The air outlet may have a total cross-sectional area of less than 0.35 square millimetres. The air outlet may have a total cross-sectional area of less than 0.3 square millimetres. The air outlet may have a total cross- sectional area of less than 0.25 square millimetres. The air outlet may have a total cross-sectional area of less than 0.2 square millimetres. The air outlet may have a total cross-sectional area of less than 0.15 square millimetres.

[0072] At least one of the one or more air inlets may have a cross-sectional area of less than 0.5 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of less than 0.45 square millimetres. At least one of the one or more air inlets may have a cross- sectional area of less than 0.4 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of less than 0.35 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of less than 0.3 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of less than 0.25 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of less than 0.2 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of less than 0.15 square millimetres.

[0073] At least one of the one or more air inlets may have a cross-sectional area of greater than or equal to 0.01 square millimetres. At least one of the one or more air inlets may have a cross- sectional area of greater than or equal to 0.05 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of greater than or equal to 0.1 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of greater than or equal to 0.15 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of greater than or equal to 0.2 square millimetres.

[0074] At least one of the one or more air inlets may have a cross-sectional area of between 0.05 square millimetres and 0.5 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of between 0.1 square millimetres and 0.45 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of between 0.15 square millimetres and 0.4 square millimetres. At least one of the one or more air inlets may have a cross-sectional area of between 0.2 square millimetres and 0.35 square millimetres.

[0075] Each of the one or more air inlets may have a cross-sectional area of less than 0.5 square millimetres. Each of the one or more air inlets may have a cross-sectional area of less than 0.45 square millimetres. Each of the one or more air inlets may have a cross-sectional area of less than 0.4 square millimetres. Each of the one or more air inlets may have a cross-sectional area of less than 0.35 square millimetres. Each of the one or more air inlets may have a cross-sectional area of less than 0.3 square millimetres. Each of the one or more air inlets may have a cross-sectional area of less than 0.25 square millimetres. Each of the one or more air inlets may have a cross- sectional area of less than 0.2 square millimetres. Each of the one or more air inlet may have a cross-sectional area of less than 0.15 square millimetres.

[0076] Each of the one or more air inlets may have a cross-sectional area of greater than or equal to 0.01 square millimetres. Each of the one or more air inlets may have a cross-sectional area of greater than or equal to 0.05 square millimetres. Each of the one or more air inlets may have a cross-sectional area of greater than or equal to 0.1 square millimetres. Each of the one or more air inlets may have a cross-sectional area of greater than or equal to 0.15 square millimetres. Each of the one or more air inlets may have a cross-sectional area of greater than or equal to 0.2 square millimetres.

[0077] Each of the one or more air inlets may have a cross-sectional area of between 0.05 square millimetres and 0.5 square millimetres. Each of the one or more air inlets may have a cross- sectional area of between 0.1 square millimetres and 0.45 square millimetres. Each of the one or more air inlets may have a cross-sectional area of between 0.15 square millimetres and 0.4 square millimetres. Each of the one or more air inlets may have a cross-sectional area of between 0.2 square millimetres and 0.35 square millimetres.

[0078] The air inlet may have a total cross-sectional area of less than 0.5 square millimetres. The air inlet may have a total cross-sectional area of less than 0.45 square millimetres. The air inlet may have a total cross-sectional area of less than 0.4 square millimetres. The air inlet may have a total cross-sectional area of less than 0.35 square millimetres. The air inlet may have a total cross- sectional area of less than 0.3 square millimetres. The air inlet may have a total cross-sectional area of less than 0.25 square millimetres. The air inlet may have a total cross-sectional area of less than 0.2 square millimetres. The air inlet may have a total cross-sectional area of less than 0.15 square millimetres.

[0079] 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. 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.

[0080] 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.

[0081] The aerosol-forming substrate may comprise or consist of homogenised tobacco material, for example a reconstituted tobacco material or a cast leaf tobacco material.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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 aerosol- formers 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 aerosolformer 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.

[0087] 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.

[0088] 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.

[0089] 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

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] The aerosol-forming substrate may comprise one or more botanicals. For example, the aerosol-forming substrate may comprise 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, and compounds of those.

[0097] 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.

[0098] 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 carboxymethyl, celluloses; dextran; and xanthan gum. A preferable binder is guar.

[0099] According to the present disclosure, an aerosol-generating device for receiving an aerosolgenerating 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 controllerto control supply of powerto 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.

[0100] The cavity may comprise an opening into which a distal end of the aerosol-generating 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.

[0101] 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.

[0102] As used herein, the term “aerosol-generating article” may refer to an article able to generate, or release, an aerosol.

[0103] 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.

[0104] 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.

[0105] As used herein, the term “aerosol generating system” refers to a combination of an aerosolgenerating device and one or more aerosol-forming articles for use with the device. An aerosolgenerating 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.

[0106] 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.

[0107] As used herein with reference to the invention, the term “nicotine”, is used to describe nicotine, nicotine base or a nicotine salt.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] Ex1 . An aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising: a first external surface; a second external surface; a cavity defined between the first external surface and the second external surface; and one or more air outlets, wherein at least one of the one or more air outlets has a cross-sectional area of less than 0.3 square millimetres.

[0116] Ex2. An aerosol-generating article according to Ex1 , comprising a frame positioned between the first external surface and the second external surface, the frame at least partially defining the cavity.

[0117] Ex3. An aerosol-generating article according to Ex1 or Ex2, wherein at least one of the first external surface and the second external surface is a planar surface. Ex4. An aerosol-generating article according to Ex3, wherein the first external surface is a first external planar surface and the second external surface is a second external planar surface.

[0118] Ex5. An aerosol-generating article according to any one of Ex1 to Ex4, wherein at least one of the one or more air outlets has a cross-sectional area of between 0.01 square millimetres and 0.3 square millimetres.

[0119] Ex6. An aerosol-generating article according to any one of Ex1 to Ex5, wherein at least one of the one or more air outlets has a cross-sectional area of between 0.05 square millimetres and 0.3 square millimetres.

[0120] Ex7. An aerosol-generating article according to any one of Ex1 to Ex6, wherein at least one of the one or more air outlets has a cross-sectional area of less than 0.25 square millimetres.

[0121] Ex8. An aerosol-generating article according to any one of Ex1 to Ex7, wherein each of the one or more air outlets has a cross-sectional area of less than or equal to 0.3 square millimetres.

[0122] Ex9. An aerosol-generating article according to any one of Ex1 to Ex8, wherein each of the one or more air outlets has a cross-sectional area of between 0.01 square millimetres and 0.3 square millimetres.

[0123] Ex10. An aerosol-generating article according to any one of Ex1 to Ex9, comprising a plurality of air outlets.

[0124] Ex11 . An aerosol-generating article according to Ex10, wherein each of the plurality of air outlets have a cross-sectional area of between 0.01 square millimetres and 0.3 square millimetres.

[0125] Ex12. An aerosol-generating article according to any one of Ex1 to Ex10, comprising an element positioned within at least one of the one or more air outlets.

[0126] Ex13. An aerosol-generating article according to Ex12, wherein the element positioned within at least one of the one or more air outlets is a porous element.

[0127] Ex14. An aerosol-generating article according to Ex12 or Ex13, wherein the element positioned within at least one of the one or more air outlets comprises at least one corrugation.

[0128] Ex15. An aerosol-generating article according to Ex14, wherein the at least one corrugation comprises a plurality of corrugations.

[0129] Ex16. An aerosol-generating article according to Ex14 or Ex15, wherein the aerosolgenerating article defines a longitudinal direction extending along the longitudinal axis of the aerosol-generating article, and wherein each corrugation extends in the longitudinal direction.

[0130] Ex17. An aerosol-generating article according to any one of Ex14 to Ex16, wherein the at least one corrugation comprises at least one corrugation arranged within the air inlet and at least one corrugation arranged in the air outlet.

[0131] Ex18. An aerosol-generating article according to any one of Ex1 to Ex17, wherein at least one of the one or more air outlets extends through the first external surface. Ex19. An aerosol-generating article according to any one of Ex1 to Ex18, wherein the frame comprises a peripheral wall circumscribing or encircling the cavity.

[0132] Ex20. An aerosol-generating article according to Ex19, wherein at least one of the one or more air outlets extends through the peripheral wall of the frame.

[0133] Ex21 . An aerosol-generating article according to Ex20, wherein at least one of the one or more air outlets extends through the peripheral frame and at least one of the one or more air outlets extends through the first external surface.

[0134] Ex22. An aerosol-generating article according to any one of Ex1 to Ex21 , comprising one or more air inlets.

[0135] Ex23. An aerosol-generating article according to Ex22, wherein at least one of the one or more air inlets has a cross-sectional area of less than or equal to 0.3 square millimetres.

[0136] Ex24. An aerosol-generating article according to Ex22 or Ex23, wherein at least one of the one or more air inlets has a cross-sectional area of between 0.01 square millimetres and 0.3 square millimetres.

[0137] Ex25. An aerosol-generating article according to any one of Ex22 to Ex24, wherein at least one of the one or more air outlets has a cross-sectional area of between 0.05 square millimetres and 0.3 square millimetres.

[0138] Ex26. An aerosol-generating article according to any one of Ex22 to Ex25, wherein at least one of the one or more air inlets has a cross-sectional area of less than or equal to 0.25 square millimetres.

[0139] Ex27. An aerosol-generating article according to any one of Ex22 to Ex26, wherein each of the one or more air inlets has a cross-sectional area of less than or equal to 0.3 square millimetres.

[0140] Ex28. An aerosol-generating article according to any one of Ex22 to Ex27, wherein each of the one or more air inlets has a cross-sectional area of between 0.01 square millimetres and 0.3 square millimetres.

[0141] Ex29. An aerosol-generating article according to any one of Ex22 to Ex28, comprising a plurality of air inlets.

[0142] Ex30. An aerosol-generating article according to Ex29, wherein each of the plurality of air inlets have a cross-sectional area of between 0.01 square millimetres and 0.3 square millimetres.

[0143] Ex31 . An aerosol-generating article according to any one of Ex22 to Ex30, comprising an element positioned within at least one of the one or more air inlets.

[0144] Ex32. An aerosol-generating article according to Ex31 , wherein the element positioned within at least one of the one or more air inlets is a porous element.

[0145] Ex33. An aerosol-generating article according to Ex31 or Ex32, wherein the element positioned within at least one of the one or more air inlets comprises at least one corrugation.

[0146] Ex34. An aerosol-generating article according to Ex33, wherein the at least one corrugation comprises a plurality of corrugations. Ex35. An aerosol-generating article according to Ex33 or Ex34, wherein the aerosolgenerating article defines a longitudinal direction extending along the longitudinal axis of the aerosol-generating article, and wherein each corrugation extends in the longitudinal direction.

[0147] Ex36. An aerosol-generating article according to any one of Ex33 to Ex35 wherein the at least one corrugation comprises at least one corrugation arranged within the air inlet and at least one corrugation arranged in the air outlet.

[0148] Ex37. An aerosol-generating article according to any one of Ex22 to Ex36, wherein at least one of the one or more air inlets extends through the first external surface.

[0149] Ex38. An aerosol-generating article according to any one of Ex22 to Ex37, comprising an airflow passage extending between one of the one or more air inlets and one of the one or more air outlets.

[0150] Ex39. An aerosol-generating article according to any one of Ex1 to Ex38, comprising one or more aerosol-generating substrates.

[0151] Ex40. An aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising: a first external surface; a second external surface; a cavity; one or more aerosol-generating substrates; and one or more air inlets, wherein at least one of the one or more air inlets has a cross-sectional area of less than 0.3 square millimetres.

[0152] Ex41. An aerosol-generating article according to Ex40, comprising a frame positioned between the first external surface and the second external surface, the frame at least partially defining the cavity.

[0153] Ex42. An aerosol-generating article according to Ex40 or Ex41 , wherein at least one of the first external surface and the second external surface is a planar surface.

[0154] Ex43. An aerosol-generating article according to Ex42, wherein the first external surface is a first external planar surface and the second external surface is a second external planar surface.

[0155] Examples will now be further described with reference to the figures in which:

[0156] Figure 1 is a perspective side view of an aerosol-generating article according to a first embodiment of the present disclosure;

[0157] Figure 2 is a perspective side view of an aerosol-generating article according to a second embodiment of the present disclosure;

[0158] Figure 3 is a schematic end view of an aerosol-generating article according to a third embodiment of the present disclosure;

[0159] Figure 4 is a schematic side view of the aerosol-generating article of Figure 3; Figure 5 is a schematic plan view of the aerosol-generating article of Figure 3;

[0160] Figure 6 shows a schematic illustration of a corrugated element as used in the aerosolgenerating article of Figure 3;

[0161] Figure 7 shows a perspective view of an aerosol-generating article according to a fourth embodiment of the present disclosure;

[0162] Figure 8 shows an exploded perspective view of the aerosol-generating article of Figure 7;

[0163] Figure 9 shows a further exploded perspective view of the aerosol-generating article of Figure 7;

[0164] Figure 10 shows a schematic transverse cross-sectional view of the aerosol-generating article of Figure 7;

[0165] Figure 11 shows a schematic longitudinal cross-sectional view of the aerosol-generating article of Figure 7;

[0166] Figure 12 shows a perspective view of an alternative example of an aerosol-generating article according to a fourth embodiment of the present disclosure;

[0167] Figure 13 shows an exploded perspective view of the aerosol-generating article of Figure 12;

[0168] Figure 14 shows an exploded perspective view of an aerosol-generating article according to a fifth embodiment of the present disclosure;

[0169] Figure 15shows a schematic transverse cross-sectional view of the aerosol-generating article of Figure 14;

[0170] Figure 16shows a schematic lateral cross-sectional view of the aerosol-generating article of Figure 14.

[0171] Figure 17 shows a schematic view of an aerosol-generating device according to an embodiment of the present disclosure, the device configured to engage with an aerosol-generating article, for example the aerosol-generating article of any of Figures 1 to 16;

[0172] Figure 18 shows a schematic end view of the aerosol-generating device of Figure 17;

[0173] Figure 19 is a schematic view showing an aerosol-generating article (for example, the aerosol-generating article of any of Figures 1 to 16) in engagement with the aerosol-generating device of Figure 17.

[0174] 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.

[0175] 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 aerosol-forming 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 aerosol-generating article 100; for example, one or both of the upper and lower surfaces 110, 120 may comprise or consist of aerosol-forming substrate.

[0176] A suitable aerosol-forming substrate may be homogenised tobacco.

[0177] 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.

[0178] The aerosol-generating article 100 has an air inlet 111 and an air outlet 112. An airflow passage extends between the air inlet 111 and the air outlet 112. In the example of Figure 1 , the air outlet has a cross-sectional area of 0.25 square millimetres and the air inlet has a cross- sectional area of 0.25 square millimetres.

[0179] In one example, the aerosol-generating article 100 may include an element such as a porous element positioned within at least one of the air inlet 111 and the air outlet 112.

[0180] 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 aerosol-generating 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 the air inlet 211 and the air outlet 212, and 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.

[0181] 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. 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] Consequently, a plurality of air inlets and a plurality of air outlets are defined by the first and second sets of longitudinally extending channels 361 , 362. A plurality of air inlets are defined by the first and second sets of longitudinally extending channels 361 , 362 at the proximal end 371 of the substrate 345. A plurality of air outlets are defined by the first and second sets of longitudinally extending channels 361 , 362 at the distal end 372 of the substrate 345.

[0186] The plurality of air inlets have a cross-sectional area of less than 0.3 square millimetres, such as 0.25 square millimetres. The plurality of air outlets have a cross-sectional area of less than 0.3 square millimetres, such as 0.25 square millimetres.

[0187] The porosity of the aerosol-generating 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.

[0188] The aerosol-forming substrate 345 may be a sheet of any suitable aerosol-forming substrate.

[0189] 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 .

[0190] 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 . 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.

[0191] 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.

[0192] 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 aerosol-generating 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.

[0193] 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 diameter of 5 millimetres. An airflow passage extends between the air inlet 411 and the air outlet 412 through the cavity 430.

[0194] The air inlet 411 has a cross-sectional area of less than 0.3 square millimetres, such as 0.28 square millimetres. The air outlet 412 has a cross-sectional area of less than 0.3 square millimetres, such as 0.28 square millimetres.

[0195] 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.

[0196] 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.

[0197] Figure 12 shows an alternative example of an aerosol-generating article 400 according to the fourth embodiment of the present disclosure. The aerosol-generating article 400 of Figure 12 has the same features as the aerosol-generating article 400 of Figure 7, except that the aerosolgenerating article 400 in Figure 12 includes a porous element 415 positioned within the air inlet 411 and a porous element 416 positioned within the air outlet 412.

[0198] Figure 13 shows an exploded view of the aerosol-generating article 400 of Figure 12.

[0199] Figure 14 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 15 and 16 show respective transverse and lateral cross-section views of the aerosol-generating article 500 of Figure 14.

[0200] 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.

[0201] 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.

[0202] 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. Figures 17 and 18 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 aerosolgenerating 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.

[0203] Figure 19 illustrates the device 6000 of Figure 17 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 aerosol-generating 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 aerosol-forming 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 aerosolgenerating article of the present disclosure.

[0204] 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 comprising: a first external surface; a second external surface; a cavity defined between the first external surface and the second external surface; and one or more air outlets, wherein at least one of the one or more air outlets has a cross-sectional area of less than 0.3 square millimetres.

2. An aerosol-generating article according to claim 1 , comprising a frame positioned between the first external surface and the second external surface, the frame at least partially defining the cavity.

3. An aerosol-generating article according to claim 1 or claim 2, wherein at least one of the first external surface and the second external surface is a planar surface.

4. An aerosol-generating article according to any one of claims 1 to 3, wherein at least one of the one or more air outlets has a cross-sectional area of between 0.01 square millimetres and 0.3 square millimetres.

5. An aerosol-generating article according to any one of claims 1 to 4, comprising a plurality of air outlets.

6. An aerosol-generating article according to any one of claims 1 to 5, comprising an element positioned within at least one of the one or more air outlets.

7. An aerosol-generating article according to claim 6, wherein the element positioned within at least one of the one or more air outlets is a porous element.

8. An aerosol-generating article according to any one of claims 1 to 7, comprising one or more air inlets.

9. An aerosol-generating article according to claim 8, wherein at least one of the one or more air inlets has a cross-sectional area of less than or equal to 0.3 square millimetres.

10. An aerosol-generating article according to claim 8 or 9, wherein at least one of the one or more air inlets has a cross-sectional area of between 0.01 square millimetres and 0.3 square millimetres.

11. An aerosol-generating article according to any one of claims 8 to 10, comprising a plurality of air inlets.

12. An aerosol-generating article according to any one of claims 8 to 11 , comprising an element positioned within at least one of the one or more air inlets.

13. An aerosol-generating article according to claim 12, wherein the element positioned within at least one of the one or more air inlets is a porous element.

14. An aerosol-generating article according to any one of claims 1 to 13, comprising one or more aerosol-generating substrates.

15. An aerosol-generating article for use with an aerosol-generating device to generate an aerosol, the aerosol-generating article comprising: a first external surface; a second external surface; a cavity; one or more aerosol-generating substrates; and one or more air inlets, wherein at least one of the one or more air inlets has a cross-sectional area of less than0.3 square millimetres.

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