Aerosol-generating article having a tubular support element

Abstract

An aerosol-generating article (10) is provided having a longitudinal axis (20) extending between an upstream end and a downstream end. The aerosol-generating article (10) includes a plug of aerosol-forming substrate (12) at the upstream end of the aerosol-generating article (10) and a hollow tubular support element (14) positioned immediately downstream of the plug of aerosol-forming substrate (12). The aerosol-generating article (10) also includes a filter segment (16) positioned at the downstream end of the aerosol-generating article (10) and immediately downstream of the hollow tubular support element (14). The ratio of the length (26) of the hollow tubular support element (14) to the length (22) of the aerosol-generating article (10) in the longitudinal axis direction (20) is between 0.3:1 and 0.5:1. The ratio of the length (24) of the plug of aerosol-forming substrate (12) to the length (26) of the hollow tubular support element (14) is between 0.5:1 and 0.8:1.

Description

[Technical field]

[0001] The present invention relates to an aerosol-generating article having a hollow tubular support element positioned immediately downstream of a plug of an aerosol-forming substrate and a filter segment positioned immediately downstream of the hollow tubular support element. [Background technology]

[0002] Aerosol-generating articles in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than burned, are well known in the art.Typically in such heated smoking articles, an aerosol is generated by transferring heat from a heat source to a physically separated aerosol-forming substrate or material, which may be located in contact with, within, around, or downstream of the heat source.During the use of the aerosol-generating article, volatile compounds are released from the aerosol-forming substrate by heat transfer from the heat source and are entrained in the air drawn through the aerosol-generating article.As the released compounds cool, they condense to form an aerosol.

[0003] Numerous prior art documents disclose aerosol generating devices for consuming aerosol-generating articles, including, for example, electrically heated aerosol generating devices, in which the aerosol is generated by heat transfer from one or more electric heater elements of the aerosol generating device to an aerosol-forming substrate of a heated aerosol-generating article.

[0004] It is also common for aerosol-generating articles for generating an inhalable aerosol upon heating to include one or more additional elements assembled with the substrate in the same wrapper. Examples of such additional elements include mouthpiece filtering segments, support elements adapted to provide structural strength to the aerosol-generating article, cooling elements adapted to favor cooling of the aerosol before it reaches the mouthpiece, etc. However, while such additional elements may have some advantageous effects, their inclusion in the aerosol-generating article generally complicates the overall structure of the article, making its manufacture more complicated and less cost-effective. Summary of the Invention [Problem to be solved by the invention]

[0005] It would be desirable to provide an aerosol-generating article that is simpler and more cost-effective to manufacture without reducing the functionality of the aerosol-generating article. [Means for solving the problem]

[0006] The present invention relates to an aerosol-generating article. The aerosol-generating article may have an upstream end and a downstream end, the aerosol-generating article defining a longitudinal direction extending between the upstream end and the downstream end. The aerosol-generating article may comprise a plug of an aerosol-forming substrate at the upstream end of the aerosol-generating article and a hollow tubular support element positioned immediately downstream of the plug of the aerosol-forming substrate. The aerosol-generating article may also comprise a filter segment positioned at the downstream end of the aerosol-generating article and immediately downstream of the hollow tubular support element. The aerosol-generating article may have a length extending longitudinally between the upstream end and the downstream end. The hollow tubular support element may have a length extending longitudinally between a first end of the hollow tubular support element and a second end of the hollow tubular support element. The ratio of the length of the hollow tubular support element to the length of the aerosol-generating article may be from about 0.3:1 to about 0.5:1.

[0007] Preferably, the present invention relates to an aerosol-generating article having an upstream end and a downstream end, the aerosol-generating article defining a longitudinal direction extending between the upstream end and the downstream end, the aerosol-generating article comprising a plug of aerosol-forming substrate at the upstream end of the aerosol-generating article, a hollow tubular support element positioned immediately downstream of the plug of aerosol-forming substrate, and a filter segment positioned at the downstream end of the aerosol-generating article and immediately downstream of the hollow tubular support element, the aerosol-generating article having a longitudinal length extending between the upstream end and the downstream end, the hollow tubular support element having a longitudinal length extending between a first end of the hollow tubular support element and a second end of the hollow tubular support element, and a ratio of the length of the hollow tubular support element to the length of the aerosol-generating article is from about 0.3:1 to about 0.5:1.

[0008] The term "aerosol-generating article" is used herein to describe an article comprising an aerosol-forming substrate that may be heated to generate and deliver an aerosol to a consumer. As used herein, the term "aerosol-forming substrate" refers to a substrate that has the ability to release volatile compounds upon heating to generate an aerosol. During use, the volatile compounds are released from the aerosol-forming substrate by heat transfer and are entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol that is inhaled by the consumer.

[0009] As used herein, the term "hollow tubular support element" means an elongated element that defines a lumen or airflow passage along its longitudinal axis. In the context of this specification, the term "tubular" is intended to encompass any tubular element having a substantially cylindrical cross-section that defines at least one airflow passage that establishes fluid communication between an upstream end of the tubular element and a downstream end of the tubular element.

[0010] The term "longitudinal" as used herein refers to a direction corresponding to a major longitudinal axis of the aerosol-generating article extending between the upstream and downstream ends of the aerosol-generating article. The terms "upstream" and "downstream" as used herein describe the relative positions of an element (or part of an element) of the aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

[0011] In use, air is drawn longitudinally through the aerosol-generating article. The terms "transverse" and "radial" refer to directions perpendicular to the longitudinal axis. Any reference to a "cross section" of an aerosol-generating article or a component of an aerosol-generating article refers to a transverse cross section, unless otherwise specified.

[0012] Advantageously, the aerosol-generating article according to the invention comprises a hollow tubular support element positioned immediately downstream of the plug of the aerosol-forming substrate and a filter segment positioned immediately downstream of the hollow tubular support element. In other words, the hollow tubular support element extends between the plug of the aerosol-forming substrate and the filter segment. Advantageously, this simplifies the structure of the aerosol-generating article compared to known articles in which multiple elements are positioned between the aerosol-forming substrate and the filter segment. Advantageously, the simplified structure facilitates a simple and cost-effective manufacturing process.

[0013] Advantageously, the aerosol-generating article according to the invention comprises a hollow tubular support element, the ratio of the length of the hollow tubular support element to the length of the aerosol-generating article being about 0.3 to 1 to about 0.5 to 1. Advantageously, the length of the hollow tubular support element compared to the length of the aerosol-generating article is greater than known aerosol-generating articles comprising tubular segments. Advantageously, the longer length of the hollow tubular support element makes it easier to handle the hollow tubular support element during manufacture of the aerosol-generating article. Advantageously, the longer length of the hollow tubular support element may provide an aerosol-generating article with the same amount of aerosol cooling as known articles having shorter tubular segments combined with an aerosol-cooling element.

[0014] The plug of aerosol-forming substrate may have a length extending longitudinally between a first end of the plug of aerosol-forming substrate and a second end of the plug of aerosol-forming substrate. The ratio of the length of the plug of aerosol-forming substrate to the length of the hollow tubular support element may be about 0.5:1 to about 0.8:1. The ratio of the length of the plug of aerosol-forming substrate to the length of the hollow tubular support element may be about 0.5:1 to about 0.7:1. The ratio of the length of the plug of aerosol-forming substrate to the length of the hollow tubular support element may be about 0.5:1 to about 0.6:1.

[0015] The length of the hollow tubular support element may be less than about 50 millimeters. The length of the hollow tubular support element may be less than about 40 millimeters. The length of the hollow tubular support element may be less than about 30 millimeters. The length of the hollow tubular support element may be greater than about 14 millimeters. The length of the hollow tubular support element may be greater than about 17 millimeters. The length of the hollow tubular support element may be between about 14 millimeters and about 22 millimeters. The length of the hollow tubular support element may be between about 17 millimeters and about 22 millimeters. The length of the hollow tubular support element may be about 21 millimeters.

[0016] The length of the plug of the aerosol-forming substrate may be from about 11 mm to about 19 mm. The length of the plug of the aerosol-forming substrate may be from about 11 mm to about 15 mm. The length of the plug of the aerosol-forming substrate may be about 12 mm.

[0017] Advantageously, a plug of aerosol-forming substrate having a length within one or more of these ranges may contain a sufficient amount of volatile compounds to facilitate the simulation of smoking a conventional cigarette.

[0018] Advantageously, a plug of aerosol-forming substrate having a length within one or more of these ranges may reduce or minimize the required size of a heater in an aerosol generating device for heating an article, which may advantageously facilitate cost-effective manufacture of the aerosol generating device.

[0019] The filter segment may have a length extending longitudinally between a first end of the filter segment and a second end of the filter segment of about 11 millimeters to about 13 millimeters. Advantageously, a filter segment having a length within this range may provide an aerosol-generating article with a desired resistance to withdrawal. In particular, since the hollow tubular support element may have a relatively low resistance to withdrawal, a filter segment having a length of about 11 millimeters to about 13 millimeters may have a sufficiently high resistance to withdrawal to provide an aerosol-generating article with a desired overall resistance to withdrawal.

[0020] The aerosol-generating article may have a length of about 40 mm to about 100 mm. The aerosol-generating article may have a length of about 40 mm to about 80 mm. The aerosol-generating article may have a length of about 40 mm to about 50 mm. The aerosol-generating article may have a length of about 45 mm.

[0021] The tubular support element may comprise at least one of polylactic acid, cellulose acetate, starch, polyhydroxyalkanoate, polypropylene, polyethylene, polystyrene, and combinations thereof. Preferably, the tubular support element comprises a bioplastic. Preferably, the hollow tubular support element comprises at least one of polylactic acid, cellulose acetate, starch, polyhydroxyalkanoate, and combinations thereof.

[0022] Advantageously, forming the hollow tubular support element from a polymer may facilitate simple and cost-effective manufacture of the hollow tubular support element, for example, the hollow tubular support element may be formed by at least one of 3D printing and injection molding.

[0023] Advantageously, forming the hollow tubular support element from at least one of polylactic acid and cellulose acetate may provide the hollow tubular support element with sufficient hardness to facilitate handling of the hollow tubular support element during manufacture of the aerosol-generating article.

[0024] Advantageously, forming the hollow tubular support element from at least one of polylactic acid and cellulose acetate may provide the hollow tubular support element with sufficient thermal capacity to provide the desired aerosol cooling function during use of the aerosol-generating article.

[0025] The hollow tubular support element preferably comprises a peripheral wall that defines the tubular shape of the hollow tubular support element. The peripheral wall may have a thickness of about 0.2 millimeters to about 5 millimeters. The peripheral wall may have a thickness of less than about 2 millimeters. The peripheral wall may have a thickness of less than about 1.5 millimeters. The peripheral wall may have a thickness of less than about 1 millimeter. The peripheral wall may have a thickness of at least about 0.2 millimeters. The peripheral wall may have a thickness of at least about 0.4 millimeters. The peripheral wall may have a thickness of at least about 0.5 millimeters. The peripheral wall may have a thickness of about 0.71 millimeters.

[0026] The term "thickness" when referring to the peripheral wall of a hollow tubular support element is used herein to refer to the smallest distance measured between the outer and inner surfaces of the peripheral wall. The distance at a given location is measured along a direction that is substantially perpendicular locally to the outer and inner surfaces of the peripheral wall. For a substantially cylindrical hollow tubular support element, i.e. a hollow tubular support element having a substantially circular cross section, the thickness of the peripheral wall is the distance between the outer and inner surfaces of the peripheral wall, measured along a substantially radial direction of the tubular element.

[0027] The hollow tubular support element may have an outer diameter of about 5 millimeters to about 12 millimeters. The hollow tubular support element may have an outer diameter of about 5 millimeters to about 10 millimeters. The hollow tubular support element may have an outer diameter of about 6 millimeters to about 8 millimeters. The hollow tubular support element may have an outer diameter of about 6.5 millimeters to about 7.5 millimeters. Advantageously, hollow tubular support elements having diameters within these ranges may facilitate the formation of an aerosol-generating article having an outer diameter similar to that of a conventional cigarette. In one preferred embodiment, the hollow tubular support element has an outer diameter of 7.1 mm + / - 10 percent.

[0028] In embodiments where the hollow tubular support element comprises a peripheral wall, the peripheral wall may define an interior volume. The hollow tubular support element may comprise a radial structure extending radially into the interior volume from at least a first point on the peripheral wall to at least a second point on the peripheral wall, whereby at least two airflow passages are defined by the peripheral wall and the radial structure, the at least two airflow passages extending in a longitudinal direction.

[0029] Advantageously, the radial structure may increase the compressive strength of the hollow tubular support element in the radial direction.

[0030] Advantageously, the radial configuration may increase the internal surface area of ​​the hollow tubular support element. Advantageously, increasing the internal surface area of ​​the hollow tubular support element may increase the aerosol cooling function of the hollow tubular support element.

[0031] The radial structure may have a cross-shaped cross-section such that the peripheral wall and the radial structure define four longitudinally extending airflow passages.

[0032] The radial structure is preferably integrally formed with the peripheral wall, in other words the radial structure and the peripheral wall are preferably formed as a single piece, for example the peripheral wall and the radial structure may be formed as a single piece in a 3D printing or injection molding process.

[0033] The radial structures may extend substantially along the entire length of the hollow tubular support element.

[0034] The radial structures may have a substantially constant cross-sectional shape along the longitudinal axis.The radial structures may have a substantially constant cross-sectional area along the longitudinal axis.

[0035] The radial structure may have a rotationally symmetric cross-sectional shape. Advantageously, the rotationally symmetric cross-sectional shape may provide at least two airflow passages having substantially the same cross-sectional area. Advantageously, this may provide a substantially uniform airflow through the hollow tubular support element.

[0036] Preferably, the first end of the hollow tubular support element is positioned immediately downstream of the plug of aerosol-forming substrate, and the radial structure is shaped to define a recess at the first end of the hollow tubular support element, the recess extending into an inner volume defined by the peripheral wall.

[0037] Providing a recess in the radial structure at the first end of the hollow tubular support element may be particularly advantageous in embodiments in which a heater is inserted into the aerosol-forming substrate to heat the aerosol-forming substrate. For example, the aerosol-generating article may be inserted into an aerosol-generating device comprising an elongated heater inserted into the aerosol-forming substrate from the upstream end of the aerosol-generating article. Advantageously, the recess in the radial structure may be arranged to receive the tip of the elongated heater. Advantageously, receiving the tip of the elongated heater in the recess in the radial structure may facilitate the insertion of the elongated heater through the entire length of the aerosol-forming substrate in the longitudinal direction. Advantageously, the recess in the radial structure may receive the tip of the elongated heater without requiring direct contact between the elongated heater and the hollow tubular support element. Advantageously, preventing direct contact between the heater and the hollow tubular support element may prevent melting of the hollow tubular support element during heating of the aerosol-forming substrate.

[0038] Providing a recess in the radial structure at the first end of the hollow tubular support element may be particularly advantageous in embodiments in which the aerosol-generating article comprises a heating element received within the aerosol-forming substrate. For example, the aerosol-generating article may comprise a susceptor positioned within the aerosol-forming substrate. The susceptor may function as a heating element for heating the aerosol-forming substrate when the susceptor is inductively heated. Advantageously, the recess in the radial structure may receive an end of the heating element. Advantageously, positioning the end of the heating element within the recess in the radial structure may facilitate the heating element extending longitudinally through the entire length of the aerosol-forming substrate. Advantageously, the recess in the radial structure may receive an end of the heating element without requiring direct contact between the heating element and the hollow tubular support element. Advantageously, preventing direct contact between the heating element and the hollow tubular support element may prevent melting of the hollow tubular support element during heating of the aerosol-forming substrate.

[0039] Preferably, the aerosol-generating article comprises an outer wrapper wound around a plug of aerosol-forming substrate, a hollow tubular support element, and a filter segment. The wrapper is preferably a paper wrapper.

[0040] The filter segments are preferably in the form of plugs.The filter segments preferably comprise fibres.The fibres of the filter segments preferably comprise cellulose acetate.

[0041] The aerosol-forming substrate preferably comprises a plant material and an aerosol former, the plant material preferably being an alkaloid-containing plant material, more preferably being a nicotine-containing plant material, more preferably being a tobacco-containing material.

[0042] Preferably, the aerosol-forming substrate comprises at least 70 percent by weight plant material on a dry weight basis, more preferably at least 90 percent by weight plant material.Preferably, the aerosol-forming substrate comprises less than 95 percent by weight plant material on a dry weight basis, such as 90-95 percent by weight plant material on a dry weight basis.

[0043] Preferably, the aerosol-forming substrate comprises at least 5 weight percent aerosol formers on a dry weight basis, more preferably at least 10 weight percent aerosol formers.Preferably, the aerosol-forming substrate comprises less than 30 weight percent aerosol formers on a dry weight basis, such as from 5 to 30 weight percent aerosol formers on a dry weight basis.

[0044] In some particularly preferred embodiments, the aerosol-forming substrate comprises a plant material and an aerosol former, the substrate having an aerosol former content of 5 to 30 weight percent on a dry weight basis. The plant material is preferably an alkaloid-containing plant material, more preferably a nicotine-containing plant material, more preferably a tobacco-containing material. Alkaloids are a class of naturally occurring nitrogen-containing organic compounds. Alkaloids are found primarily in plants, but also in bacteria, fungi, and animals. Examples of alkaloids include, but are not limited to, caffeine, nicotine, theobromine, atropine, and tubocurarine. A preferred alkaloid is nicotine, which may be found in tobacco.

[0045] The aerosol-forming substrate may comprise nicotine. The aerosol-forming substrate may comprise tobacco, for example a tobacco-containing material containing volatile tobacco flavour compounds that are released from the aerosol-forming substrate upon heating. In a preferred embodiment, the aerosol-forming substrate may comprise homogenized tobacco material, for example cast leaf tobacco. The aerosol-forming substrate may comprise both solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds that are released from the substrate upon heating. The aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former. Examples of suitable aerosol formers are glycerin and propylene glycol.

[0046] In some preferred embodiments, the aerosol-forming substrate may comprise a textured sheet of homogenized tobacco material having an aerosol former content of 5-30% by weight on a dry weight basis. The use of a textured sheet of homogenized tobacco material may advantageously facilitate assembling the homogenized tobacco material sheet to form the aerosol-forming substrate.

[0047] As used herein, the term "crimped sheet" refers to a sheet having a plurality of substantially parallel ridges or corrugations. Preferably, the substantially parallel ridges or corrugations extend along or parallel to the longitudinal axis of the aerosol-generating article when the aerosol-generating article is assembled. This advantageously facilitates assembling the crimped sheet of homogenized tobacco material to form an aerosol-forming substrate. However, it will be appreciated that a crimped sheet of homogenized tobacco material for inclusion in an aerosol-generating article may alternatively or additionally have a plurality of substantially parallel ridges or corrugations that are disposed at an acute or obtuse angle relative to the longitudinal axis of the aerosol-generating article when the aerosol-generating article is assembled.

[0048] The aerosol-forming substrate may be in the form of a plug comprising the aerosol-forming material surrounded by a paper or other wrapper. When the aerosol-forming substrate is in the form of a plug, the entire plug, including any wrapper, is considered to be the aerosol-forming substrate.

[0049] The aerosol-forming substrate of the present invention preferably comprises an aerosol former. As used herein, the term "aerosol former" is used to describe any suitable known compound or mixture of compounds that facilitates the formation of an aerosol during use and that is substantially resistant to thermal decomposition at the operating temperature of the aerosol-generating article.

[0050] Suitable aerosol formers are well known in the art and include, but are not limited to, polyhydric alcohols (such as propylene glycol, triethylene glycol, 1,3-butanediol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate, etc.), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.). Preferred aerosol formers are polyhydric alcohols (e.g., propylene glycol, triethylene glycol, 1,3-butanediol, and most preferably glycerin) or mixtures thereof.

[0051] The aerosol-forming substrate may comprise a single aerosol former, alternatively, the aerosol-forming substrate may comprise a combination of two or more aerosol formers.

[0052] The aerosol-forming substrate is preferably in the form of a rod comprising an assembly of sheets of aerosol-forming material, for example an assembly of sheets of homogenized tobacco, or an assembly of sheets comprising a nicotine salt and an aerosol former.

[0053] Aerosol-forming substrates comprising an aggregate of homogenized tobacco sheets for use in aerosol-generating articles may be prepared by methods well known in the art (e.g., the methods disclosed in International Patent Publication No. WO 2012 / 164009 A2).

[0054] The aerosol-forming substrate preferably has an outer diameter of at least 5 millimeters. The aerosol-forming substrate may have an outer diameter of about 5 millimeters to about 12 millimeters, for example about 5 millimeters to about 10 millimeters, or about 6 millimeters to about 8 millimeters. In a preferred embodiment, the aerosol-forming substrate has an outer diameter of 7.2 millimeters + / - 10 percent.

[0055] The aerosol-forming substrate may have a length of about 5 mm to about 15 mm, for example about 8 mm to about 12 mm. In one embodiment, the aerosol-forming substrate may have a length of about 10 mm. In a preferred embodiment, the aerosol-forming substrate has a length of about 12 mm. The aerosol-forming substrate is preferably substantially cylindrical.

[0056] According to a second aspect of the present invention there is provided an aerosol generation system comprising an aerosol generating device according to the first aspect of the present invention and an aerosol-generating article according to any of the embodiments described herein, the aerosol generating device comprising a cavity arranged to receive at least a portion of the aerosol-generating article, and a heater positioned to heat the plug of aerosol-forming substrate when the aerosol-generating article is received in the cavity.

[0057] As used herein, the term "aerosol-generating device" refers to a device that includes a heater that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol.

[0058] A heater may be positioned within the cavity and may be arranged for insertion into the plug of the aerosol-forming substrate when the aerosol-generating article is received within the cavity. The heater may extend into the cavity.

[0059] The heater may be arranged to extend around an outer surface of the aerosol-generating article when the aerosol-generating article is received within the cavity.

[0060] Preferably the heater is an electric heater.

[0061] The electric heater may extend into the cavity. The electric heater may be an elongated electric heater. The elongated electric heater may have a distal end arranged to be received within the aerosol-generating article and a proximal end opposite the distal end. The electric heater may be blade-shaped. The electric heater may be pin-shaped. The electric heater may be cone-shaped.

[0062] The elongated electric heater may comprise at least one resistive heating track. The at least one resistive heating track may be surrounded by an electrically insulating substrate. The at least one resistive heating track may be embedded within the electrically insulating substrate. The electrically insulating substrate may comprise a ceramic. The electrically insulating substrate may be received within a tubular shell. The tubular shell may comprise at least one metal.

[0063] The electric heater may comprise a resistive heating element, in use, an electric current is supplied to the resistive heating element to generate heat by resistive heating.

[0064] Suitable materials for forming the resistive heating element include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys, and composites made of ceramic and metallic materials. Such composites may include doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel-, iron-, cobalt-, and stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum-based alloys.

[0065] In some embodiments, the resistive heating element comprises one or more stamped sections of an electrically resistive material (such as stainless steel. Alternatively, the resistive heating element may comprise a heating wire or filament (e.g., Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire).

[0066] The electric heater may comprise an electrically insulating substrate, with the resistive heating element being provided on the electrically insulating substrate. The electrically insulating substrate may be a ceramic material such as zirconia or alumina. The electrically insulating substrate preferably has a thermal conductivity of about 2 watts per metre per kelvin or less.

[0067] The electric heater may be disposed to extend around an outer surface of the aerosol-generating article received within the cavity. The electric heater may have a tubular shape. The electric heater may comprise an electrically insulating substrate and at least one resistive heating track on the electrically insulating substrate. The electrically insulating substrate may comprise a flexible sheet. Advantageously, the flexible sheet may facilitate manufacturing the electric heater in a flat state and subsequently deforming the flexible sheet into a desired shape. For example, the electric heater may be formed in a flat state and then rolled into a tubular shape. The electrically insulating substrate may comprise a polyimide film. The at least one resistive heating track may comprise at least one metal. The at least one resistive heating track may comprise a metal. The at least one resistive heating track may comprise a metal alloy. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steels, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel-, iron-, cobalt-, stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum-based alloys.

[0068] The at least one resistive heating track may define a number of heating zones.

[0069] The at least one resistive heating track may comprise a plurality of heating tracks. The plurality of heating tracks may define a plurality of heating zones.

[0070] The at least one resistive heating track may comprise a single heating track comprising a plurality of portions, each portion defining a heating zone.

[0071] Advantageously, at least some of the heating zones may be heated to different temperatures during use. Advantageously, at least some of the heating zones may be heated at different times during use. Each heating zone may be defined by a single resistive heating track. Each heating zone may be defined by multiple resistive heating tracks.

[0072] The electric heater may include an induction heating element. In use, when the aerosol-generating article is received within the cavity, the induction heating element inductively heats the susceptor material to heat the aerosol-generating article. The susceptor material may form part of the aerosol-generating device. The susceptor material may form part of the aerosol-generating article.

[0073] The aerosol generating device preferably comprises a power supply and a controller arranged to provide power from the power supply to the electric heater during use of the aerosol generating device.

[0074] The controller is preferably arranged to provide power from the power source to the electric heater in accordance with a predetermined heating cycle when the aerosol generating device is used to heat an aerosol-generating article received within the cavity.

[0075] The power source may be a DC voltage source. In a preferred embodiment, the power source is a battery. For example, the power source may be a nickel metal hydride battery, a nickel cadmium battery, or a lithium-based battery (e.g., a lithium cobalt battery, a lithium iron phosphate battery, or a lithium polymer battery). Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging and may have a capacity that allows for the storage of sufficient energy to use the aerosol generating device with one or more aerosol-generating articles.

[0076] The aerosol generating device preferably comprises at least one air inlet, preferably in fluid communication with the upstream end of the cavity. In embodiments where the aerosol generating device comprises an elongated electric heater, the elongated electric heater preferably extends into the cavity from the upstream end of the cavity.

[0077] The aerosol generating device may include a sensor for detecting airflow indicative of a user taking a puff. The airflow sensor may be an electromechanical device. The airflow sensor may be any of a mechanical device, an optical device, an opto-mechanical device, and a microelectromechanical system (MEMS) based sensor. The aerosol generating device may include a manually operable switch for a user to initiate a puff.

[0078] The aerosol generating device may comprise a temperature sensor. The temperature sensor may be mounted on a printed circuit board. In embodiments where the aerosol generating device comprises an electric heater, the temperature sensor may be mounted on the electric heater. In embodiments where the electric heater comprises an electrically insulating substrate, the temperature sensor may be mounted on the electrically insulating substrate. In embodiments where the electric heater is an elongated electric heater, the temperature sensor may be mounted on a distal end of the elongated electric heater.

[0079] The temperature sensor may detect the temperature of the electric heater or the temperature of the aerosol-generating article received within the cavity. The temperature sensor may be a thermistor. The temperature sensor may be a thermocouple. The temperature sensor may comprise circuitry configured to measure the resistivity of the electric heater and to derive the temperature of the electric heater by comparing the measured resistivity to a calibration curve of resistivity versus temperature.

[0080] Advantageously, deriving the temperature of the electric heater may facilitate control of the temperature to which the electric heater is heated during use. The controller may be configured to adjust the supply of power to the electric heater in response to changes in the measured resistivity of the electric heater.

[0081] Advantageously, deriving the temperature of the electric heater may facilitate detection of a puff, for example a measured decrease in temperature of the electric heater may correspond to a user puffing or inhaling the aerosol-generating article.

[0082] It will be appreciated that any feature described with respect to one aspect of the invention is equally applicable to any other aspect of the invention.

[0083] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: [Brief description of the drawings]

[0084] [Figure 1] FIG. 1 shows a longitudinal cross-section of an aerosol-generating article according to an embodiment of the invention. [Diagram 2] FIG. 2 shows a transverse cross-section of the hollow tubular support element of the aerosol-generating article of FIG. [Diagram 3] FIG. 3 shows a transverse cross-sectional view of an alternative arrangement of the hollow tubular support element of the aerosol-generating article of FIG. [Figure 4] FIG. 4 shows a longitudinal cross-sectional view of the hollow tubular support element of FIG. [Diagram 5] FIG. 5 shows a transverse cross-sectional view of a further alternative arrangement of the hollow tubular support element of the aerosol-generating article of FIG. [Figure 6] FIG. 6 shows a longitudinal cross-sectional view of an aerosol generating system including the aerosol generating article of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0085] 1 shows an aerosol-generating article 10 according to one embodiment of the present invention. The aerosol-generating article 10 comprises a plug of aerosol-forming substrate 12, which contains tobacco, and which is positioned at the upstream end of the aerosol-generating article 10. Positioned immediately downstream of the plug of aerosol-forming substrate 12 is a hollow tubular support element 14 formed from polylactic acid. Positioned immediately downstream of the hollow tubular support element 14, and at the downstream end of the aerosol-generating article 10, is a filter segment 16, which comprises fibers of cellulose acetate. The aerosol-generating article 10 also comprises an outer wrapper 18 formed from paper and which surrounds the plug of aerosol-forming substrate 12, the hollow tubular support element 14, and the filter segment 16.

[0086] The aerosol-generating article 10 defines a longitudinal axis 20 and has a length 22 extending between upstream and downstream ends of the aerosol-generating article 10. The length 22 of the aerosol-generating article 10 is approximately 45 millimeters.

[0087] The plug of aerosol-forming substrate 12, the hollow tubular support element 14, and the filter segment 16 each have respective lengths 24, 26, 28. The length 24 of the plug of aerosol-forming substrate 12 is 12 millimeters. The length 26 of the hollow tubular support element 14 is 21 millimeters. The length 28 of the filter segment 18 is 12 millimeters. The ratio of the length 26 of the hollow tubular support element 14 to the length 22 of the aerosol-generating article 10 is 0.47 to 1.

[0088] 2 shows a side cross-sectional view of hollow tubular support element 14. Hollow tubular support element 14 includes a peripheral wall 30 that defines the tubular shape of hollow tubular support element 14. Peripheral wall 30 has an exterior surface 32 and an interior surface 34. Interior surface 34 defines an interior volume 36 that forms an airflow passage 38 that extends along length 26 of hollow tubular support element 14. Peripheral wall 30 has a thickness 40 of 0.71 millimeters. Hollow tubular support element 14 has a circular annular cross-sectional shape. Hollow tubular support element 14 has an outer diameter 42 of 7.1 millimeters and an inner diameter 44 of 5.68 millimeters.

[0089] Figure 3 shows a side cross-sectional view of an alternative arrangement of hollow tubular support element 14. In the arrangement shown in Figure 3, hollow tubular support element 14 includes a radial structure 46 that includes a single wall that extends across interior volume 36 defined by peripheral wall 30. Radial structure 46 divides interior volume 36 into two airflow passages 38. Radial structure 46 is integrally formed with peripheral wall 30.

[0090] FIG. 4 shows a longitudinal cross-sectional view of the hollow tubular support element 14 of FIG. 3 taken along the line 344-344 shown in FIG. 3. The hollow tubular support element 14 comprises a recess 48 formed in the radial structure 46 at a first end 50 of the hollow tubular support element 14. When the hollow tubular support element 14 is assembled with the plug of aerosol-forming substrate 12 and the filter segment 16 to form the aerosol-generating article 10, the first end 50 comprising the recess 48 is positioned adjacent to the plug of aerosol-forming substrate 12. In other words, the recess 48 is positioned at the upstream end of the hollow tubular support element 14. The second end 52 of the hollow tubular support element 14 forms the downstream end of the hollow tubular support element 14. During use of the aerosol-generating article 10 in an aerosol-generating device, the recess 48 may receive the tip of a heater inserted through the plug of aerosol-forming substrate 12.

[0091] Figure 5 shows a side cross-sectional view of a further alternative arrangement of hollow tubular support elements 14, similar to the arrangement shown in Figure 3. In the arrangement shown in Figure 5, the radial structures 46 are cross-shaped and divide the interior volume 36 into four airflow passages 48. The hollow tubular support elements 14 may also include recesses 48 in the radial structures 46, as already described with reference to Figure 4.

[0092] FIG. 6 shows a longitudinal cross-sectional view of an aerosol-generating system 100 comprising an aerosol-generating device 102 and the aerosol-generating article 10 of FIG. 1. The aerosol-generating device 102 comprises a housing 104 defining a cavity 106 for receiving the aerosol-generating article 10. An elongated electric heater 108 extends into the cavity 106 and is arranged for insertion into the plug of the aerosol-forming substrate 12 when the aerosol-generating article 10 is inserted into the cavity 106. The aerosol-generating device 102 also comprises a power source 110 and a controller 112. In use, the controller 112 controls the supply of power from the power source 110 to the elongated electric heater 108. The elongated electric heater 108 heats the plug of the aerosol-forming substrate 12 to release volatile compounds therefrom. When a user draws on the filter segment 16, the released compounds are drawn into the hollow tubular support element 14 where they cool and form an aerosol. The aerosol is then drawn through filter segment 16 where it is delivered to the user.

Claims

1. 1. An aerosol-generating article having an upstream end and a downstream end, the article defining a longitudinal direction extending between said upstream end and said downstream end, a plug of aerosol-forming substrate at an upstream end of the aerosol-generating article, the aerosol-forming substrate comprising an aerosol former; and a hollow tubular support element positioned immediately downstream of the plug of aerosol-forming substrate; a filter segment located at the downstream end of the aerosol-generating article and immediately downstream of the hollow tubular support element, the aerosol-generating article has a length extending along the longitudinal axis between the upstream end and the downstream end; the plug of aerosol-forming substrate has a length extending in the longitudinal direction between a first end of the plug of aerosol-forming substrate and a second end of the plug of aerosol-forming substrate; the hollow tubular support element has a length extending in the longitudinal direction between a first end of the hollow tubular support element and a second end of the hollow tubular support element; a ratio of the length of the hollow tubular support element to the length of the aerosol-generating article is between 0.3:1 and 0.5:1; an aerosol-generating article, wherein the ratio of said length of said plug of aerosol-forming substrate to said length of said hollow tubular support element is between 0.5:1 and 0.8:1;

2. 2. The aerosol-generating article of claim 1, wherein the length of the hollow tubular support element is from about 14 millimeters to about 22 millimeters.

3. 3. The aerosol-generating article of claim 1 or claim 2, wherein the length of the plug of aerosol-forming substrate is between 11 millimeters and 19 millimeters.

4. 4. The aerosol-generating article of claim 1, wherein the filter segment has a length extending in the longitudinal direction between a first end of the filter segment and a second end of the filter segment of between 11 millimeters and 13 millimeters.

5. 5. An aerosol-generating article according to claim 1, wherein the length of the aerosol-generating article is between 40 millimetres and 50 millimetres.

6. 6. An aerosol-generating article according to any one of claims 1 to 5, wherein the hollow tubular support element comprises a polymer, preferably at least one of polylactic acid, cellulose acetate, starch, and polyhydroxyalkanoate.

7. 7. An aerosol-generating article according to any one of claims 1 to 6, wherein the hollow tubular support element has an outer diameter of between 6 millimeters and 8 millimeters.

8. 8. An aerosol-generating article according to any one of claims 1 to 7, wherein the hollow tubular support element comprises a peripheral wall defining the tubular shape of the hollow tubular support element, the peripheral wall having a thickness of between 0.5 millimeters and 1 millimeter.

9. The hollow tubular support element comprises: a peripheral wall defining the tubular shape of the hollow tubular support element, the peripheral wall defining an interior volume; a radial structure, at least two airflow passages defined by the peripheral wall and the radial structure, the radial structure extending radially within the inner volume from at least a first point on the peripheral wall to at least a second point on the peripheral wall such that the at least two airflow passages extend in the longitudinal direction; and The aerosol-generating article of any one of claims 1 to 8, comprising:

10. 10. The aerosol-generating article of claim 9, wherein the radial structure has a cross-shaped cross-section, whereby the peripheral wall and the radial structure define four airflow passages extending along the longitudinal axis.

11. 11. The aerosol-generating article of claim 9 or claim 10, wherein the first end of the hollow tubular support element is positioned immediately downstream of the plug of the aerosol-forming substrate, and the radial structure is shaped to define a recess at the first end of the hollow tubular support element, the recess extending into the inner volume defined by the peripheral wall.

12. 12. An aerosol-generating article according to any one of claims 1 to 11, further comprising an outer wrapper wound around the plug of aerosol-forming substrate, the hollow tubular support element, and the filter segment.

13. 13. The aerosol-generating article of any one of claims 1 to 12, wherein the aerosol former comprises at least one of propylene glycol, triethylene glycol, 1,3-butanediol, a polyhydric alcohol such as glycerin, an ester of a polyhydric alcohol such as glycerol monoacetate, diacetate or triacetate, and an aliphatic ester of a mono-, di- or polycarboxylic acid such as dimethyl dodecanedioate, dimethyl tetradecanedioate.

14. The aerosol-generating article of any one of claims 1 to 13, wherein the aerosol former comprises at least one of propylene glycol, triethylene glycol, 1,3-butanediol, and glycerin.

15. 1. An aerosol generation system comprising: An aerosol-generating article according to any one of claims 1 to 14; an aerosol generating device comprising a cavity arranged to receive at least a portion of the aerosol-generating article, and a heater positioned to heat the plug of aerosol-forming substrate when the aerosol-generating article is received in the cavity.

16. 16. The aerosol generating system of claim 15, wherein the heater is positioned within the cavity and is arranged for insertion into a plug of the aerosol-forming substrate when the aerosol-generating article is received within the cavity.

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