Aerosol-generating article comprising first tubular element and second tubular element

Abstract

An aerosol-generating article (1) comprises a plurality of elements assembled in the form of a strip. The plurality of elements comprises an aerosol-forming substrate (10). The plurality of elements further comprise a first tubular element (20) comprising an upstream end wall (21) defining a first opening (22) for allowing fluid communication between an interior of the first tubular element and an exterior of the first tubular element. The plurality of elements further comprise a second tubular element (30) comprising a second tubular element end wall (31) defining a second opening (32) for allowing fluid communication between an interior of the second tubular element and an exterior of the second tubular element. The first tubular element (20) is positioned within the strip upstream of and adjacent to the second tubular element (30).

Description

Technical Field

[0001] The present disclosure relates to an aerosol-generating article comprising an aerosol-forming substrate, wherein the aerosol-generating article is adapted to generate an inhalable aerosol. Background Art

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

[0003] It is known to provide an aerosol-generating article with one or more elements in addition to the aerosol-forming substrate, the one or more elements being configured to perform certain functions to enhance the consumer experience. For example, WO 2013 / 120565 A2 discloses an aerosol-generating article comprising an aerosol cooling element for cooling the aerosol formed by the substrate. In one embodiment disclosed in WO 2013 / 120565 A2, a hollow cellulose acetate tube is positioned downstream of the aerosol-forming substrate, and an aerosol cooling element made of a polylactic acid sheet is positioned downstream of the hollow cellulose acetate tube. The function of the hollow cellulose acetate tube is described as preventing the aerosol-forming substrate from being pushed downstream when a heating element is inserted into the aerosol-forming substrate.

[0004] Providing such elements for an aerosol-generating article in addition to the aerosol-forming substrate can increase the cost and complexity of manufacturing the aerosol-generating article. In addition, these elements may have an undesirable effect on the resistance to draw (RTD) of the aerosol-generating article. For example, an aerosol-generating article with too low or too high an RTD may result in an unsatisfactory consumer experience. Summary of the Invention

[0005] There is a desire to provide an aerosol-generating article having one or more elements that can enhance the consumer experience but is relatively simple and inexpensive to manufacture. In particular, it is desirable that the RTD of the elements can be controlled to provide a satisfactory RTD.

[0006] The present disclosure relates to an aerosol-generating article. The aerosol-generating article may include a plurality of components assembled in the form of a strip. The plurality of components may include an aerosol-forming substrate. The plurality of components may further include a first tubular component. The first tubular component may include an upstream end wall that defines a first opening for allowing fluid communication between the interior and the exterior of the first tubular component. The plurality of components may further include a second tubular component. The second tubular component may include a second tubular component end wall that defines a second opening for allowing fluid communication between the interior and the exterior of the second tubular component. The first tubular component may be positioned upstream and adjacent to the second tubular component within the strip.

[0007] According to the present disclosure, there is provided an aerosol-generating article. The aerosol-generating article includes a plurality of components assembled in the form of a strip. The plurality of components includes an aerosol-forming substrate. The plurality of components further includes a first tubular component that includes an upstream end wall that defines a first opening for allowing fluid communication between the interior and the exterior of the first tubular component. The plurality of components further includes a second tubular component that includes a second tubular component end wall that defines a second opening for allowing fluid communication between the interior and the exterior of the second tubular component. The first tubular component is positioned upstream and adjacent to the second tubular component within the strip.

[0008] The first tubular component may be referred to as an upstream tubular component. The second tubular component may be referred to as a downstream tubular component.

[0009] The aerosol-generating article may include a substrate portion. The substrate portion may include an aerosol-forming substrate. The substrate portion may include a capsule. The aerosol-forming substrate may be disposed within the capsule.

[0010] By providing two separate tubular components each having an end wall adjacent to each other, the tubular components may provide one or more functions to enhance the consumer experience. For example, when positioned downstream of the aerosol-forming substrate, the tubular component may act as one or more of an aerosol-cooling component and a filter component. Additionally, when positioned upstream of the aerosol-forming substrate, the tubular component may act as a mouthpiece rod. This means that the number of components in the aerosol-generating article can be reduced, and the number of different types of components that need to be manufactured can be reduced, since the tubular component can perform many different functions. Advantageously, this means that the manufacturing process can be simplified and the manufacturing cost can be reduced.

[0011] Providing two separate tubular elements each having an end wall adjacent to each other, rather than a single tubular element having two end walls, provides a number of benefits. For example, it has been found that in a continuous manufacturing process, providing two tubular elements each having a single end wall may be faster and more efficient than providing a single tubular element having two end walls. This is because only a single end wall needs to be formed on each tubular element. As another example, each tubular element can be optimized depending on its position within the aerosol-generating article. This can include forming each tubular element from a different material or from a material of a different thickness. For example, the first tubular element may be exposed to a high temperature from a heating element. This means that the first tubular element may need to be made of a heat-resistant material. On the other hand, the second tubular element may not be exposed to a high temperature, but may be exposed to saliva from the user's mouth. This means that the second tubular element may need to have a hydrophobic coating. Advantageously, this can result in an optimized aerosol-generating article that is relatively simple to manufacture and cost-effective.

[0012] As used herein, the term "aerosol-generating article" refers to an article that is capable of generating an inhalable aerosol and delivering the inhalable aerosol to a consumer.

[0013] As used herein, the term "aerosol-forming substrate" refers to a substrate that is capable of forming an inhalable aerosol. The aerosol-forming substrate may be capable of releasing volatile compounds to form an inhalable aerosol. Such volatile compounds can be released by heating the aerosol-forming substrate.

[0014] As used herein, the term "bar" refers to an elongate element. The bar may have a substantially polygonal cross-sectional shape. Preferably, a circular, oval or elliptical cross-sectional shape.

[0015] As used herein, the term "elongate" means that the length dimension of the element is greater than its width dimension or its diameter dimension, e.g., twice or more its width dimension or its diameter dimension.

[0016] As used herein, the term "transverse" refers to a direction perpendicular to the longitudinal direction. Unless otherwise specified, any reference to a "cross-section" of an aerosol-generating article or a component of an aerosol-generating article refers to a cross-section.

[0017] 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 end and the downstream end of the aerosol-generating article. During use, air is drawn through the aerosol-generating article in the longitudinal direction.

[0018] As used herein, the terms "upstream" and "downstream" refer to the relative positions of elements or portions of elements of the aerosol-generating article with respect to the longitudinal direction.

[0019] As used herein, the term "length" refers to the dimension of an aerosol-generating article or a component of an aerosol-generating article in the longitudinal direction. For example, it can be used to denote the dimension of an aerosol-forming substrate, a first tubular element, or a second tubular element in the longitudinal direction.

[0020] As used herein, the term "equivalent diameter" refers to the diameter of a circular opening having the same cross-sectional area as an opening.

[0021] As used herein, the term "tubular element" refers to an elongate element that defines a lumen or an air flow passage in its longitudinal direction. In particular, the term "tubular" is used to describe a tubular element having a substantially circular cross-sectional shape and defining at least one air flow conduit that establishes an uninterrupted fluid communication between the upstream end and the downstream end of the tubular element. However, it should be understood that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular element may be possible. For example, the tubular element may have a circular, oval, or elliptical cross-sectional shape.

[0022] As used herein, the term "upstream end wall" refers to the wall at the most upstream end of the first tubular element. The upstream end wall extends substantially transversely to the longitudinal direction of the first tubular element. The material forming the upstream end wall may be substantially air-impermeable.

[0023] As used herein, the term "second tubular element end wall" refers to the wall at the most distal end of the second tubular element. The second tubular element end wall extends substantially transversely to the longitudinal direction of the second tubular element. The material forming the second tubular element end wall may be substantially air-impermeable.

[0024] As used herein, the term "adjacent to" means that a first element of an aerosol-generating article is longitudinally positioned beside a second element of the aerosol-generating article. In particular, the term indicates that there are no other elements of the aerosol-generating article disposed between the first element and the second element of the aerosol-generating article in the longitudinal direction.

[0025] As used herein, the term "filter" refers to a section or an element of an aerosol-generating article that is configured to at least partially remove gaseous or particulate phase components or both gaseous and particulate phase components from the mainstream aerosol drawn through the filter.

[0026] As used herein, the term "aerosol generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol from the aerosol-forming substrate. The aerosol generating device may be a heated aerosol generating device. The aerosol generating device may be an electrically heated aerosol generating device. For example, the aerosol generating device may include one or more components for supplying energy from a power source to the aerosol-forming substrate to generate an aerosol. The aerosol generating device may be a smoking device that interacts with an aerosol-forming substrate to generate an aerosol that can be directly inhaled into a user's lungs through the user's mouth.

[0027] In a conventional cigarette, a user applies a flame to one end of the cigarette, and the local heat provided by the flame and oxygen in the air causes the end of the cigarette to be lit, and the resulting combustion generates inhalable smoke. In contrast, in a heated aerosol generating article, the aerosol is generated by heating rather than burning the aerosol-forming substrate. Known heated aerosol generating articles include, for example, electrically heated aerosol generating articles, and aerosol generating articles in which the aerosol is generated by heat transfer from a combustible fuel element or heat source to a physically separated aerosol-forming substrate.

[0028] The aerosol generating article according to the present disclosure may be a heated aerosol generating article. The aerosol generating article may be an electrically heated aerosol generating article. Compared with an aerosol generating article in which the aerosol-forming substrate is configured to burn, the heated aerosol generating article may produce a smaller number of components that need to be filtered before being inhaled by the consumer. Advantageously, this may mean that the aerosol generating article may have fewer components downstream of the aerosol-forming substrate, resulting in a cheaper aerosol generating article to manufacture. Additionally, this may mean that for an aerosol generating article of the same size, the aerosol generating article may be provided with a larger aerosol-forming substrate, which may provide a longer usage process for the consumer.

[0029] The downstream end of the first tubular element may be spaced apart from the upstream end of the second tubular element in the longitudinal direction. A blank space gap may separate the downstream end of the first tubular element and the upstream end of the second tubular element in the longitudinal direction of the aerosol generating article. The gap may have a length of 5 millimeters or less. The gap may have a length of 4 millimeters or less. The gap may have a length of 3 millimeters or less. The gap may have a length of 2 millimeters or less. The gap may have a length of 1 millimeter or less. Advantageously, compared with a single tubular element having the same distance between the upstream end wall and the downstream end wall, such a gap may increase the length of the internal passage between the upstream end wall of the first tubular element and the end wall of the second tubular element, while reducing the amount of material required and thus reducing the cost. This is especially the case when the end wall of the second tubular element is positioned at the downstream end of the second tubular element.

[0030] The downstream end of the first tubular element can be in physical contact with the upstream end of the second tubular element. The downstream end of the first tubular element can abut the upstream end of the second tubular element. This may mean that there is no gap between the first tubular element and the second tubular element. Advantageously, this can prevent one or more of air, volatile compounds, and aerosols from escaping in the radial direction through the gap between the first tubular element and the second tubular element. Advantageously, this can also mean that the gap between the first tubular element and the second tubular element does not need to be defined by a non-porous wrapper.

[0031] The downstream end of the first tubular element can overlap the upstream end of the second tubular element in the longitudinal direction. For example, it can overlap between about 1 millimeter and about 5 millimeters. In particular, the downstream end of the first tubular element can define the upstream end of the second tubular element. Alternatively, the upstream end of the second tubular element can define the downstream end of the first tubular element. The downstream end of the first tubular element can be positioned within the second tubular element, or the upstream end of the second tubular element can be positioned within the first tubular element. Advantageously, this can prevent one or more of air, volatile compounds, and aerosols from escaping in the radial direction through the gap between the first tubular element and the second tubular element.

[0032] The first tubular element and the second tubular element can be positioned upstream of the aerosol-forming substrate. Thus, the first tubular element and the second tubular element can act as a mouthpiece while allowing air and a heating element to enter the aerosol-generating article through the first opening. Advantageously, compared to conventional mouthpieces, such as those made of cellulose acetate, this mouthpiece may be relatively inexpensive.

[0033] The first tubular element can be the most upstream element of the aerosol-generating article. The first tubular element can be positioned at the most upstream end of the aerosol-generating article. The upstream end wall of the first tubular element can be positioned at the most upstream end of the aerosol-generating article. Advantageously, this can mean that the first tubular element and the second tubular element can prevent any element or part of any element of the aerosol-generating article from leaving the downstream end of the aerosol-generating article.

[0034] The second tubular element may be positioned adjacent to the upstream end of the substrate portion. The second tubular element may be positioned adjacent to the upstream end of the aerosol-forming substrate. There may be a gap between the downstream end of the second tubular element and the upstream end of the aerosol-forming substrate. The gap may have a length of at least about 1 mm, at least about 2 mm, at least about 3 mm, at least about 4 mm or at least about 5 mm. The gap may have a length between about 1 mm and about 5 mm. This gap may allow air leaving the downstream end of the second tubular element to move in a radial direction before passing through the aerosol-forming substrate. This is particularly the case when the end wall of the second tubular element is positioned at the downstream end of the second tubular element. Advantageously, this may allow air to pass through the entire cross-section of the aerosol-forming substrate. It has been found that a gap having a length between about 1 mm and about 5 mm provides sufficient area for air to move in the radial direction without creating large regions of recirculating air.

[0035] The second tubular element may be in physical contact with the upstream end of the aerosol-forming substrate. The downstream end of the second tubular element may be in physical contact with the upstream end of the aerosol-forming substrate. Advantageously, this may prevent movement of the aerosol-generating article towards the downstream end of the aerosol-generating article. Additionally, due to the restriction of movement of the aerosol-forming substrate, this may ensure that the heating element can be positioned consistently relative to the aerosol-forming substrate. The second tubular element may be in physical contact with the upstream end of the substrate portion. The downstream end of the second tubular element may be in physical contact with the upstream end of the substrate portion.

[0036] The first tubular element and the second tubular element may be positioned downstream of the aerosol-forming substrate. Thus, advantageously, the first tubular element and the second tubular element may interact with one or more of air, volatile compounds and aerosol downstream of the aerosol-forming substrate. For example, the first tubular element and the second tubular element may act as one or more of a cooling element, a filter element and a mouthpiece.

[0037] In many known aerosol-generating articles, there is a filter element positioned at the downstream end of the aerosol-generating article. Typically, the filter elements are constructed in such a way that they impart an RTD to the aerosol flowing through them. This means that when configuring the overall RTD of the aerosol-generating article, the RTD through the filter element must be taken into account. This can present a challenge when there are many components within the aerosol-generating article and a consistent RTD is desired between manufactured aerosol-generating articles. In some known aerosol-generating articles, the filter elements are made of cellulose acetate which can impart an RTD.

[0038] In the aerosol-generating article of the present disclosure, there may be no filter element made of cellulose acetate located downstream of the second tubular element. In fact, there may be no filter element located downstream of the second tubular element. Additionally or alternatively, any element located downstream of the second tubular element may have a draw resistance less than that of one or more of the first tubular element, the second tubular element, or a combination of the first tubular element and the second tubular element. For example, any element located downstream of the second tubular element may have a draw resistance of less than about 30 mm H2O, preferably less than about 20 mm H2O, more preferably less than about 10 mm H2O, or most preferably about 0 mm H2O. Advantageously, this means that it is easier to provide a consistent RTD between manufactured aerosol-generating articles. The term "any element located downstream of the second tubular element" includes the case where there is no element located downstream of the second tubular element.

[0039] Any element located downstream of the second tubular element may be hollow. Any element located downstream of the second tubular element may be tubular.

[0040] The second tubular element may be the most downstream element of the aerosol-generating article. Thus, there may be no element located between the downstream end of the second tubular element and the most downstream end of the aerosol-generating article. Advantageously, this may mean that the aerosol-generating article is easier to manufacture due to a reduced number of components that need to be assembled within the aerosol-generating article. Additionally, this may allow for constriction of the second opening of the second tubular element to accelerate the aerosol into the consumer's mouth without the accelerated aerosol being disrupted by an element downstream of the second tubular element. This may provide a pleasant sensation for the consumer.

[0041] The downstream end of the second tubular element may be spaced apart from the downstream end of the aerosol-generating article. By spacing apart the downstream end of the second tubular element from the downstream end of the aerosol-generating article, the aerosol stream exiting the downstream end of the second tubular element has a region in which it expands before entering the consumer's mouth. Advantageously, this may deliver an aerosol stream to the consumer's mouth that has a sensation of a larger volume, which may provide greater consumer satisfaction. This is particularly the case when the end wall of the second tubular element is located at the downstream end of the second tubular element.

[0042] The downstream end of the second tubular element can be positioned between about 3 millimeters and about 20 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element can be positioned between about 3 millimeters and about 15 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element can be positioned between about 3 millimeters and about 10 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element can be positioned between about 3 millimeters and about 8 millimeters from the downstream end of the aerosol-generating article. These ranges provide a compromise between providing an area for the aerosol to expand before entering the consumer's mouth and not significantly increasing the overall length of the aerosol-generating article and thus the cost. Advantageously, it has been found that the range between about 3 millimeters and about 8 millimeters provides a good compromise between the area for aerosol expansion and the length of the aerosol-generating article.

[0043] The downstream end of the second tubular element can be positioned less than 20 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element can be positioned less than 15 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element can be positioned less than 10 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element can be positioned less than 5 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element can be positioned less than 3 millimeters from the downstream end of the aerosol-generating article.

[0044] The second tubular element can be positioned at the most downstream end of the aerosol-generating article. The downstream end of the second tubular element can be positioned at the most downstream end of the aerosol-generating article. Advantageously, the second tubular element can thus act as a mouthpiece element and support the consumer's lips, which define the aerosol-generating article when the consumer draws on the aerosol-generating article.

[0045] The upstream end wall of the first tubular element can be positioned adjacent to the aerosol-forming substrate and not in physical contact with the aerosol-forming substrate. A blank space gap can separate the upstream end wall of the first tubular element and the downstream end of the aerosol-forming substrate in the longitudinal direction of the aerosol-generating article. The upstream end wall of the first tubular element can be positioned adjacent to the substrate portion. A blank space gap can separate the upstream end wall of the first tubular element and the downstream end of the substrate portion. The gap can be 5 millimeters or less. The gap can be 4 millimeters or less. The gap can be 3 millimeters or less. The gap can be 2 millimeters or less. The gap can be 1 millimeter or less. Advantageously, such a gap can provide space for loose particles or chunks from the aerosol-forming substrate to accumulate during use of the aerosol-generating article.

[0046] The first tubular element may be positioned adjacent to the downstream end of the aerosol - forming substrate. The first tubular element may be in physical contact with the downstream end of the aerosol - forming substrate. The upstream end wall of the first tubular element may be in physical contact with the downstream end of the aerosol - forming substrate. Advantageously, the physical contact between the upstream end of the tubular element and the aerosol - forming substrate may prevent the aerosol - forming substrate from moving downstream, for example when the aerosol - forming substrate dries out and shrinks, or when the heating element is inserted into the aerosol - forming substrate from the upstream end of the aerosol - generating article. The first tubular element may be positioned adjacent to the downstream end of the substrate portion. The first tubular element may be in physical contact with the downstream end of the substrate portion. The upstream end wall of the first tubular element may be in physical contact with the downstream end of the substrate portion.

[0047] The upstream end wall may be formed by a first folded end portion. The second tubular element end wall may be formed by a second folded end portion. By providing end walls formed by the folded end portions of the respective tubular elements, each tubular element can be configured to have a desired RTD through the configuration of the size and shape of the end wall and the opening. In particular, each tubular element and its end wall can be manufactured efficiently and at high speed, with a satisfactory RTD and low RTD variability from one article to another. Additionally, the configuration of each tubular element and its end wall means that the RTD can be positioned at a specific longitudinal location of the tubular element, i.e., at the end wall, rather than being distributed continuously along the length of the tubular element. Advantageously, this means that the tubular element can be configured to have more consistent properties while maintaining a cost - effective manufacturing process.

[0048] The first folded end portion may be a flanged end portion. The second folded end portion may be a flanged end portion.

[0049] The second tubular element end wall may be positioned at the upstream end of the second tubular element. Alternatively, the second tubular element end wall may be positioned at the downstream end of the second tubular element. That is to say, the second tubular end wall may be referred to as the downstream end wall.

[0050] There may be no end wall at the downstream end of the first tubular element. There may be no end wall at the upstream end of the second tubular element. Alternatively, there may be no end wall at the downstream end of the second tubular element. There may be no end wall at both the downstream end of the first tubular element and the upstream end of the second tubular element. Advantageously, this can provide an unobstructed passage for fluid flow between the upstream end wall of the first tubular element and the downstream end wall of the second tubular element.

[0051] The first tubular element may include a first cavity extending from the upstream end wall of the first tubular element to the downstream end of the first tubular element. The first cavity may be empty. Advantageously, this can provide an uninterrupted passage for fluid flow through the first tubular element.

[0052] The first chamber may have a diameter that is at least about 50% of the diameter of the first tubular element. The first chamber may have a diameter that is at least about 60% of the diameter of the first tubular element. The first chamber may have a diameter that is at least about 70% of the diameter of the first tubular element. The first chamber may have a diameter that is at least about 80% of the diameter of the first tubular element. The first chamber may have a diameter that is at least about 90% of the diameter of the first tubular element. Preferably, the first chamber may have a diameter that is at least about 95% of the diameter of the first tubular element. Advantageously, it has been found that a diameter of the first chamber that is at least about 50% of the diameter of the first tubular element provides a first tubular element with good structural rigidity. It has been found that a compromise between structural rigidity and a reduction in the material used can be achieved when the diameter of the chamber is at least about 95% of the diameter of the first tubular element.

[0053] The diameter of the first chamber may increase between the upstream end wall of the first tubular element and the downstream end of the first tubular element. The diameter of the first chamber may increase from the upstream end wall of the first tubular element to the downstream end of the first tubular element. Advantageously, the increased diameter can be used to slow down the flow within the first tubular element.

[0054] The diameter of the first chamber may decrease between the upstream end wall of the first tubular element and the downstream end of the first tubular element. The diameter of the first chamber may decrease from the upstream end wall of the first tubular element to the downstream end of the first tubular element. Advantageously, the decreased diameter can be used to accelerate the flow within the first tubular element.

[0055] The diameter of the first chamber may be substantially constant between the upstream end wall of the first tubular element and the downstream end of the first tubular element. The diameter of the chamber may be substantially constant from the upstream end wall of the first tubular element to the downstream end of the first tubular element. Advantageously, the substantially constant diameter can help maintain a constant flow rate throughout the first chamber, which can allow the flow to have an equal contact time with all parts of the inner wall of the first chamber.

[0056] The second tubular element may include a second chamber extending from the upstream end of the second tubular element to the downstream end of the second tubular element. The second chamber may be empty. Advantageously, this can provide an uninterrupted passage for fluid flow through the second tubular element.

[0057] The second cavity may have a diameter that is at least about 50% of the diameter of the second tubular element. The second cavity may have a diameter that is at least about 60% of the diameter of the second tubular element. The second cavity may have a diameter that is at least about 70% of the diameter of the second tubular element. The second cavity may have a diameter that is at least about 80% of the diameter of the second tubular element. The second cavity may have a diameter that is at least about 90% of the diameter of the second tubular element. The second cavity may have a diameter that is at least about 95% of the diameter of the second tubular element. Advantageously, it has been found that a diameter of the second cavity that is at least about 50% of the diameter of the second tubular element provides a second tubular element with good structural rigidity. It has been found that a compromise between structural rigidity and a reduction in the material used can be achieved when the diameter of the second cavity is at least about 95% of the diameter of the second tubular element.

[0058] The diameter of the second cavity may increase between the upstream end of the second tubular element and the downstream end of the second tubular element. The diameter of the second cavity may increase from the upstream end of the second tubular element to the downstream end of the second tubular element.

[0059] The diameter of the second cavity may decrease between the upstream end of the second tubular element and the downstream end of the second tubular element. The diameter of the second cavity may decrease from the upstream end of the second tubular element to the downstream end of the second tubular element.

[0060] The diameter of the second cavity may be substantially constant between the upstream end of the second tubular element and the downstream end of the second tubular element. The diameter of the second cavity may be substantially constant from the upstream end of the second tubular element to the downstream end of the second tubular element.

[0061] The diameter of the first cavity may be greater than the diameter of the second cavity. The diameter of the first cavity may be less than the diameter of the second cavity. The diameter of the first cavity may be substantially the same as the diameter of the second cavity.

[0062] The aerosol-generating article may include a continuous cavity extending from the upstream end wall of the first tubular element to the downstream end of the second tubular element. The continuous cavity may have a uniform diameter along the entire length of the continuous cavity. The continuous cavity may be substantially empty. The continuous cavity may be formed by the first cavity and the second cavity.

[0063] The first tubular element may have a length greater than the length of the second tubular element. The first tubular element may have a length less than the length of the second tubular element. The first tubular element has a length substantially equal to the length of the second tubular element.

[0064] The first tubular element may have a length of at least about 10% of the length of the aerosol-generating article. The first tubular element may have a length of at least about 20% of the length of the aerosol-generating article. The first tubular element may have a length of at least about 30% of the length of the aerosol-generating article. The first tubular element may have a length of at least about 40% of the length of the aerosol-generating article. The first tubular element may have a length of at least about 50% of the length of the aerosol-generating article.

[0065] The first tubular element may have a length between about 10 millimeters and about 30 millimeters. The first tubular element may have a length between about 10 millimeters and about 25 millimeters. The first tubular element may have a length between about 10 millimeters and about 20 millimeters. The first tubular element may have a length between about 10 millimeters and about 15 millimeters.

[0066] The second tubular element may have a length of at least about 10% of the length of the aerosol-generating article. The second tubular element may have a length of at least about 20% of the length of the aerosol-generating article. The second tubular element may have a length of at least about 30% of the length of the aerosol-generating article. The second tubular element may have a length of at least about 40% of the length of the aerosol-generating article. The second tubular element may have a length of at least about 50% of the length of the aerosol-generating article.

[0067] The second tubular element may have a length between about 10 millimeters and about 30 millimeters. The second tubular element may have a length between about 10 millimeters and about 25 millimeters. The second tubular element may have a length between about 10 millimeters and about 20 millimeters. The second tubular element may have a length between about 10 millimeters and about 15 millimeters.

[0068] The first opening may be radially aligned with the second opening. That is, when viewed in the longitudinal direction, at least 90% of the cross-sectional area of the first opening overlaps with the cross-sectional area of the second opening. Advantageously, this may allow the heating element to be easily inserted through both the first opening and the second opening before contacting the aerosol-forming substrate. Alternatively, the first opening may be radially offset from the second opening. That is, when viewed in the longitudinal direction, the cross-sectional area of the first opening does not overlap with the cross-sectional area of the second opening. Advantageously, the radially offset openings may promote turbulence within the tubular element.

[0069] The first opening may be radially offset from the radial central axis of the first tubular element. That is, the geometric center of the first opening does not coincide with the radial central axis of the first tubular element. When the first tubular element is positioned downstream of the aerosol-forming substrate and the first opening is radially offset from the radial central axis, an aerosol generated in the aerosol-forming substrate, such as an aerosol generated near the radial central axis, can be caused to move radially outward as the aerosol is drawn through the aerosol-forming substrate. This is particularly advantageous in embodiments where the heat source is positioned at a radial central position within the aerosol-forming substrate, such as a sensor element or a heating element of a device inserted into the substrate during use. Typically, in such embodiments, the peripheral portion of the substrate is cooler than the radial central portion of the substrate. Thus, as the aerosol moves radially outward within the aerosol-forming substrate, the aerosol can be cooled. This can be particularly beneficial during the user's first puff on the article when most of the aerosol can be formed near the heat source. This offset first opening can also prevent a heat source positioned radially centered within the aerosol-forming substrate from migrating downstream. This is particularly evident when the upstream end wall of the first tubular element is in physical contact with the downstream end of the aerosol-forming substrate.

[0070] The first opening may be radially centered. That is, the perimeter of the first opening may define the radial central axis of the first tubular element, and the geometric center of the first opening may coincide with the radial central axis of the first tubular element. For example, the first opening may be at the radially central position of the upstream end wall. The second opening may be radially centered. That is, the perimeter of the second opening may define the radial central axis of the second tubular element, and the geometric center of the second opening may coincide with the radial central axis of the second tubular element. For example, the second opening may be at the radially central position of the end wall of the second tubular element.

[0071] The first opening may have an equivalent diameter equal to or greater than about 10% of the diameter of the upstream end wall. The first opening may have an equivalent diameter equal to or greater than about 20% of the diameter of the upstream end wall. The first opening may have an equivalent diameter equal to or greater than about 30% of the diameter of the upstream end wall. The first opening may have an equivalent diameter equal to or greater than about 40% of the diameter of the upstream end wall. The first opening may have an equivalent diameter equal to or greater than about 50% of the diameter of the upstream end wall.

[0072] The first opening may have an equivalent diameter between about 1 mm and about 12 mm. The first opening may have an equivalent diameter between about 1 mm and about 9 mm. The first opening may have an equivalent diameter between about 1 mm and about 6 mm. Preferably, the first opening may have an equivalent diameter between about 1 mm and about 3 mm. Advantageously, when the first tubular element is downstream of the aerosol-forming substrate, it has been found that a first opening having an equivalent diameter between about 1 mm and about 3 mm provides a good compromise between providing an acceptable RTD for the first tubular element and preventing the migration of undesired components of the aerosol-forming substrate downstream. In a particularly preferred embodiment, the first opening has an equivalent diameter of about 2.5 mm.

[0073] The second opening may have an equivalent diameter equal to or greater than about 10% of the diameter of the end wall of the second tubular element. The second opening may have an equivalent diameter equal to or greater than about 20% of the diameter of the end wall of the second tubular element. The second opening may have an equivalent diameter equal to or greater than about 30% of the diameter of the end wall of the second tubular element. The second opening may have an equivalent diameter equal to or greater than about 40% of the diameter of the end wall of the second tubular element. The second opening may have an equivalent diameter equal to or greater than about 50% of the diameter of the end wall of the second tubular element.

[0074] The second opening may have an equivalent diameter between about 1 mm and about 12 mm. The second opening may have an equivalent diameter between about 1 mm and about 9 mm. The second opening may have an equivalent diameter between about 1 mm and about 6 mm. Preferably, the second opening may have an equivalent diameter between about 1 mm and about 3 mm. Advantageously, when the second tubular element is downstream of the aerosol-forming substrate, a second opening having an equivalent diameter between about 1 mm and about 3 mm provides a good compromise between providing an acceptable RTD for the second tubular element and filtering out undesired volatile compounds before the aerosol exits the downstream end of the aerosol-generating article. In a particularly preferred embodiment, the second opening has an equivalent diameter of about 2.5 mm.

[0075] The first opening may have an equivalent diameter substantially equal to the equivalent diameter of the second opening. For example, both the first opening and the second opening may have an equivalent diameter of about 2.5 mm. The first opening may have an equivalent diameter smaller than the equivalent diameter of the second opening. For example, the first opening may have an equivalent diameter of about 2 mm and the second opening may have an equivalent diameter of about 4 mm. The first opening may have an equivalent diameter smaller than the equivalent diameter of the second opening. For example, the first opening may have an equivalent diameter of about 4 mm and the second opening may have an equivalent diameter of about 2 mm.

[0076] The first opening may have an equivalent diameter equal to or greater than 500% of the equivalent diameter of the second opening. The first opening may have an equivalent diameter equal to or greater than 400% of the equivalent diameter of the second opening. The first opening may have an equivalent diameter equal to or greater than 300% of the equivalent diameter of the second opening. The first opening may have an equivalent diameter equal to or greater than 200% of the equivalent diameter of the second opening. The first opening may have an equivalent diameter equal to or greater than 150% of the equivalent diameter of the second opening. The first opening may have an equivalent diameter equal to or greater than 140% of the equivalent diameter of the second opening. The first opening may have an equivalent diameter equal to or greater than 130% of the equivalent diameter of the second opening. The first opening may have an equivalent diameter equal to or greater than 120% of the equivalent diameter of the second opening. The first opening may have an equivalent diameter equal to or greater than 110% of the equivalent diameter of the second opening.

[0077] The second opening may have an equivalent diameter equal to or greater than 500% of the equivalent diameter of the first opening. The second opening may have an equivalent diameter equal to or greater than 400% of the equivalent diameter of the first opening. The second opening may have an equivalent diameter equal to or greater than 300% of the equivalent diameter of the first opening. The second opening may have an equivalent diameter equal to or greater than 200% of the equivalent diameter of the first opening. The second opening may have an equivalent diameter equal to or greater than 150% of the equivalent diameter of the first opening. The second opening may have an equivalent diameter equal to or greater than 140% of the equivalent diameter of the first opening. The second opening may have an equivalent diameter equal to or greater than 130% of the equivalent diameter of the first opening. The second opening may have an equivalent diameter equal to or greater than 120% of the equivalent diameter of the first opening. The second opening may have an equivalent diameter equal to or greater than 110% of the equivalent diameter of the first opening.

[0078] The upstream end wall may define a plurality of openings for allowing fluid communication between the interior and the exterior of the first tubular element. The second tubular element end wall may define a plurality of openings for allowing fluid communication between the interior and the exterior of the second tubular element. Advantageously, providing a plurality of openings instead of a single opening may allow each opening among the plurality of openings to have a small equivalent diameter while still providing an acceptable RTD.

[0079] The number of openings defined in the upstream end wall may be greater than the number of openings defined in the second tubular element end wall. The number of openings defined in the upstream end wall may be less than the number of openings defined in the second tubular element end wall.

[0080] An aerosol-generating article may include a pre-rod located upstream of an aerosol-forming substrate. Advantageously, such a pre-rod may prevent the aerosol-forming substrate from spilling out of the upstream end of the aerosol-generating article. The pre-rod may also assist in positioning the aerosol-forming substrate a predetermined distance from the upstream end of the aerosol-generating article for optimal engagement with a heat source, such as a heating element. The pre-rod may also make it less likely for a consumer to misuse the aerosol-generating article and ignite the end of the aerosol-generating article in the same way as a conventional cigarette.

[0081] The pre-rod may be the most upstream element of the aerosol-generating article. The pre-rod may physically contact the upstream end of the aerosol-forming substrate.

[0082] The pre-rod may be penetrated by a heating element such that the heating element can contact or penetrate the aerosol-forming substrate. In such embodiments, the aerosol-forming substrate may contract during the aerosol-generating phase to contact the heating element. The aerosol-forming substrate may also contract such that its contact with the outer wrapper of the aerosol-generating article is reduced. In the absence of a pre-rod, the withdrawal of the heating element from the strip may also result in the withdrawal of the aerosol-forming substrate due to the increased adhesion of the aerosol-forming substrate to the heating element combined with the decreased adhesion of the aerosol-forming substrate to the cigarette paper. However, the pre-rod may facilitate the removal or withdrawal of the heating element from the strip by restricting the movement of the aerosol-forming substrate towards the distal end of the strip. The pre-rod may block the passage of the aerosol-forming substrate and thus prevent the aerosol-forming substrate from being withdrawn from the aerosol-generating article.

[0083] The pre-rod may be made of a filter material that allows air to be drawn through the pre-rod. This may allow a consumer to draw air through the aerosol-generating article via the pre-rod. The pre-rod may conveniently be formed of the same material as a conventional cigarette filter tip. For example, the pre-rod may be formed of a section of cellulose acetate tow. The permeability of the pre-rod may be varied to assist in controlling the draw resistance through the aerosol-generating article. Alternatively, the pre-rod may be made of a material that is impermeable to air. In such embodiments, the aerosol-generating article may be configured such that air flows into the aerosol-forming substrate through the sidewalls of the aerosol-generating article upstream of the aerosol-forming substrate.

[0084] The pre-rod may be a hollow element, for example, the pre-rod may be in the form of a tube. The pre-rod may be made of cellulose acetate, for example, the pre-rod may be a hollow cellulose acetate tube.

[0085] The front rod may comprise one or more materials selected from ceramics, polymers, biopolymers, metals, zeolites, paper, cardboard, inert materials, and inorganic materials. The front rod has a diameter that is substantially equal to the diameter of the aerosol-generating article. Preferably, the front rod has a diameter between about 5 millimeters and about 10 millimeters. The front rod may have a length of the front rod between about 1 millimeter and about 10 millimeters, between about 2 millimeters and about 8 millimeters, between about 4 millimeters and about 8 millimeters. The front rod may be cylindrical and may have a length of at least 2 millimeters to facilitate assembly of the aerosol-generating article, preferably at least 3 millimeters or at least 4 millimeters. The front rod may have a length of about 5 millimeters. Advantageously, a longer rod may also provide improved cleaning, as there is a greater amount of front rod material available for wiping the heating element when the heating element is withdrawn from the rod.

[0086] One or both of the first tubular element and the second tubular element may comprise a hydrophobic coating. The first tubular element may comprise a hydrophobic coating. At least a portion of the first tubular element may comprise a hydrophobic coating. The second tubular element may comprise a hydrophobic coating. At least a portion of the second tubular element may comprise a hydrophobic coating. The volatile compounds and air cool as they pass through the tubular elements. The volatile compounds may condense on one or both of the upstream tubular element and the second tubular element. Advantageously, the hydrophobic coating may prevent the structural integrity of the first tubular element and the second tubular element from deteriorating due to the condensed substances.

[0087] The upstream end wall of the first tubular element may comprise a hydrophobic coating. The second tubular element end wall of the second tubular element may comprise a hydrophobic coating. The first cavity of the first tubular element may comprise a hydrophobic coating. The second cavity of the second tubular element may comprise a hydrophobic coating.

[0088] As used herein, the term "hydrophobic" refers to a surface that exhibits the property of repelling water. One useful way to determine this is to measure the water contact angle. The "water contact angle" is the angle through the liquid, measured conventionally, when the liquid / vapor interface meets the solid surface. It quantifies the wettability of the solid surface by the liquid via Young's equation.

[0089] The hydrophobic coating may have a Cobb water absorption (ISO 535:1991) value (at 60 seconds) of less than about 40 g / m2, less than about 35 g / m2, less than about 30 g / m2, or less than about 25 g / m2.

[0090] The hydrophobic coating may have a water contact angle of at least about 90 degrees, at least about 95 degrees, at least about 100 degrees, at least about 110 degrees, at least about 120 degrees, at least about 130 degrees, at least about 140 degrees, at least about 150 degrees, at least about 160 degrees, or at least about 170 degrees. Hydrophobicity is determined by using the TAPPI T558 om-97 test, and the results are presented as the interfacial contact angle and reported in "degrees", and the range can be from close to zero to close to 180 degrees. When the contact angle is not specified together with the term "hydrophobic", the water contact angle is at least 90 degrees.

[0091] One or both of the first tubular element and the second tubular element may be formed of a paper material such as paper, cardboard, or carton board. One or both of the first tubular element and the second tubular element may be formed of a plurality of overlapping paper layers, such as a plurality of parallel wound paper layers or a plurality of helically wound paper layers. Forming one or both of the first tubular element and the second tubular element of a plurality of overlapping paper layers may help improve the collapse or deformation resistance of the tubular element.

[0092] In the case where one or both of the first tubular element and the second tubular element are formed of a paper material, the paper material may have a basis weight of at least about 90 g / m². The paper material may have a basis weight of less than about 300 g / m². The paper material may have a basis weight of about 100 to about 200 g / m². Advantageously, providing such a wall basis weight for one or both of the first tubular element and the second tubular element may help improve the collapse or deformation resistance of the tubular element.

[0093] The first tubular element may be formed of a first material. The second tubular element may be formed of a second material. The basis weight of the first material may be greater than the basis weight of the second material. The basis weight of the first material may be less than the basis weight of the second material. The first material and the second material may be the same material, such as carton board, but may have different basis weights. The first material may be any of the above materials. The second material may be any of the above materials.

[0094] The first tubular element may have a tubular wall thickness of at least about 0.1 mm, more preferably at least about 0.2 mm. The first tubular element may have a tubular wall thickness of less than about 1.5 mm, preferably less than about 1.25 mm. In a preferred embodiment, the first tubular element has a tubular wall thickness of less than about 1 mm. Thus, the first tubular element preferably has a tubular wall thickness between about 0.1 mm and about 1.5 mm, or between about 0.2 mm and about 1.25 mm, or between about 0.5 mm and about 1 mm. In some embodiments, the first tubular element may have a tubular wall thickness between about 0.15 mm and about 0.6 mm. Advantageously, providing such a tubular wall thickness to the first tubular element may help improve the collapse or deformation resistance of the first tubular element.

[0095] As used herein, the term "tubular wall thickness" refers to the thickness of the tubular wall extending from the upstream end to the downstream end of the tubular element as measured in the radial direction.

[0096] The second tubular element may have a tubular wall thickness of at least about 0.1 mm, more preferably at least about 0.2 mm. The second tubular element may have a tubular wall thickness of less than about 1.5 mm, preferably less than about 1.25 mm. In a preferred embodiment, the second tubular element has a tubular wall thickness of less than about 1 mm. Thus, the second tubular element preferably has a tubular wall thickness between about 0.1 mm and about 1.5 mm, or between about 0.2 mm and about 1.25 mm, or between about 0.5 mm and about 1 mm. In some embodiments, the second tubular element may have a tubular wall thickness between about 0.15 mm and about 0.6 mm. Advantageously, providing such a tubular wall thickness for the second tubular element can help improve the collapse or deformation resistance of the second tubular element.

[0097] The tubular wall thickness of the first tubular element may be greater than the tubular wall thickness of the second tubular element. Alternatively, the tubular wall thickness of the first tubular element may be less than the tubular wall thickness of the second tubular element. Alternatively, the tubular wall thickness of the first tubular element may be substantially the same as the tubular wall thickness of the second tubular element.

[0098] The aerosol-generating article may include an outer wrapper that at least defines a first tubular element and a second tubular element. The outer wrapper may extend from the upstream end of the first tubular element to the downstream end of the second tubular element. The outer wrapper may define the outer surface of the aerosol-generating article. The outer wrapper may at least define an aerosol-forming substrate, a first tubular element, and a second tubular element. The outer wrapper may define all of the plurality of elements of the aerosol-generating article assembled in the form of a strip.

[0099] The outer wrapper may be a tipping paper. The outer wrapper may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers include, but are not limited to: cigarette paper; and filter tip segment wrappers. Suitable non-paper wrappers for particular embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material. In certain preferred embodiments, the outer wrapper may be formed from a laminated material including a plurality of layers. Preferably, the wrapper is formed from an aluminum co-laminated sheet. In cases where the aerosol-forming substrate is to be ignited rather than heated in the intended manner, using a co-laminated sheet including aluminum advantageously prevents the combustion of the outer wrapper.

[0100] The aerosol-generating article comprises a ventilation zone. Advantageously, this can increase cooling of the air and volatile compounds within the interior of one or both of the upstream tubular element and the second tubular element by drawing in cooler outside air. It can also increase turbulence within the tubular element, particularly where the ventilation zone causes air to be drawn into the tubular element in a direction transverse to the longitudinal axis of the tubular element.

[0101] The ventilation zone may be positioned between the upstream end of the aerosol-generating article and the downstream end of the aerosol-generating article. The ventilation zone may be positioned downstream of the aerosol-forming substrate. The ventilation zone may be positioned downstream of the first tubular element. Alternatively, the ventilation zone may be positioned upstream of the first tubular element. The ventilation zone may be positioned downstream of the second tubular element. Alternatively, the ventilation zone may be positioned upstream of the second tubular element.

[0102] As described above, in an embodiment, the first tubular element and the second tubular element can be longitudinally spaced apart. The ventilation zone can be positioned downstream of the first tubular element and upstream of the second tubular element. The ventilation zone can be positioned between the downstream end of the first tubular element and the upstream end of the second tubular element. The ventilation zone can be positioned between the first tubular element and the second tubular element.

[0103] The ventilation zone may be positioned at a position along the first tubular element. The ventilation zone may be positioned at a position along the second tubular element. For example, the ventilation zone may be positioned longitudinally between the upstream end and the downstream end of the first tubular element or the second tubular element. The features of the ventilation zone are described below with respect to the aerosol generating article. However, it should be appreciated that they may also be applied directly to the tubular element itself.

[0104] The ventilation zone may be located between about 5 mm and about 15 mm from the upstream end wall of the first tubular element or the end wall of the second tubular element. The ventilation zone may be located at least 2 mm from the upstream end wall of the first tubular element or the end wall of the second tubular element, more preferably at least 3 mm from the upstream end wall of the first tubular element or the end wall of the second tubular element, and even more preferably at least 5 mm from the upstream end wall of the first tubular element or the end wall of the second tubular element.

[0105] The ventilation zone may be located less than 20 mm from the upstream end wall of the first tubular element or the end wall of the second tubular element, more preferably less than 15 mm from the upstream end wall of the first tubular element or the end wall of the second tubular element, even more preferably less than 10 mm from the upstream end wall of the first tubular element or the end wall of the second tubular element.

[0106] The ventilation zone may be located between about 1 millimeter and about 10 millimeters from the upstream end wall of the first tubular element or the end wall of the second tubular element, more preferably between about 2 millimeters and about 8 millimeters from the upstream end wall of the first tubular element or the end wall of the second tubular element, and even more preferably between about 3 millimeters and about 6 millimeters from the upstream end wall of the first tubular element or the end wall of the second tubular element.

[0107] The ventilation zone may be located at least 1 millimeter from the upstream end wall of the first tubular element or the end wall of the second tubular element. More preferably, the ventilation zone is located at least 2 millimeters from the upstream end wall of the first tubular element or the end wall of the second tubular element. Even more preferably, the ventilation zone is located at least 3 millimeters from the upstream end wall of the first tubular element or the end wall of the second tubular element.

[0108] The ventilation zone may be located less than 10 millimeters from the upstream end wall of the first tubular element or the end wall of the second tubular element. More preferably, the ventilation zone may be located less than 8 millimeters from the upstream end wall of the first tubular element or the end wall of the second tubular element. Even more preferably, the ventilation zone may be located less than 6 millimeters from the upstream end wall of the first tubular element or the end wall of the second tubular element.

[0109] The ventilation zone may include a plurality of perforations through the peripheral wall or the tubular wall of one or more of the aerosol - generating article, the first tubular element, and the second tubular element. Preferably, the ventilation zone includes at least one row of circumferential perforations. The ventilation zone may include two rows of circumferential perforations. For example, the perforations may be formed during the manufacture of the aerosol - generating article. Preferably, each row of circumferential perforations includes 8 to 30 perforations.

[0110] The aerosol - generating article according to the present invention may have a ventilation level of at least about 5%.

[0111] Throughout the present specification, the term "ventilation level" is used to represent the volume ratio of the air flow entering the aerosol - generating article via the ventilation zone (ventilation air flow) to the sum of the aerosol air flow and the ventilation air flow. The greater the ventilation level, the higher the dilution of the aerosol flow delivered to the consumer.

[0112] The aerosol - generating article may generally have a ventilation level of at least about 10%, preferably at least about 15%, more preferably at least about 20%.

[0113] In a preferred embodiment, the aerosol - generating article has a ventilation level of at least about 25%. The aerosol - generating article preferably has a ventilation level of less than about 60%. The aerosol - generating article may have a ventilation level of less than or equal to about 45%. More preferably, the ventilation level of the aerosol - generating article may be less than or equal to about 40%, and even more preferably less than or equal to about 35%.

[0114] In a particularly preferred embodiment, the aerosol-generating article has a ventilation level of about 30%. The ventilation level of the aerosol-generating article can be from about 20% to about 60%, preferably from about 20% to about 45%, more preferably from about 20% to about 40%. The ventilation level of the aerosol-generating article can be from about 25% to about 60%, preferably from about 25% to about 45%, more preferably from about 25% to about 40%. In a further embodiment, the aerosol-generating article has a ventilation level of from about 30% to about 60%, preferably from about 30% to about 45%, more preferably from about 30% to about 40%. The aerosol-generating article can have a ventilation level between about 30% and about 60%. The aerosol-generating article can have a ventilation level between about 40% and about 50%.

[0115] In some particularly preferred embodiments, the aerosol-generating article has a ventilation level of from about 28% to about 42%. In some particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 30%.

[0116] Embodiments in which the ventilation zone is provided at a location along the first tubular element or the second tubular element can offer a number of advantages. For example, and without wishing to be bound by theory, the inventors have found that the temperature drop caused by the entry of cooler external air into the tubular element via the ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

[0117] The aerosol-generating article can include a susceptor element positioned in thermal contact with the aerosol-forming substrate. The susceptor element can be positioned within the aerosol-forming substrate. The susceptor element can be positioned within the aerosol-forming substrate. The susceptor element can be an elongate susceptor element. The susceptor element can extend longitudinally within the aerosol-forming substrate. The susceptor element can extend along the radial central axis of the aerosol-forming substrate.

[0118] As used herein, the term "susceptor element" refers to a material that can convert electromagnetic energy into heat. When located within an alternating magnetic field, eddy currents induced in the susceptor element cause heating of the susceptor element. When the elongate susceptor element is in thermal contact with the aerosol-forming substrate, the aerosol-forming substrate is heated by the susceptor element.

[0119] When used to describe a susceptor element, the term "elongate" means that the length dimension of the susceptor element is greater than its width dimension or its thickness dimension, such as more than twice its width dimension or its thickness dimension.

[0120] The sensor element can be arranged substantially longitudinally within the aerosol - forming substrate. This means that the length dimension of the elongate sensor element is arranged to be generally parallel to the longitudinal direction of the aerosol - forming substrate, for example within plus or minus 10 degrees parallel to the longitudinal direction of the aerosol - forming substrate. In a preferred embodiment, the elongate sensor element can be positioned at a radially - central position within the aerosol - forming substrate and extend along the longitudinal axis of the aerosol - forming substrate.

[0121] The sensor element can extend from the upstream end of the aerosol - forming substrate to the downstream end of the aerosol - forming substrate. Preferably, the sensor element extends all the way to the downstream end of the aerosol - forming substrate. The sensor element can extend all the way to the upstream end of the aerosol - forming substrate. In a particularly preferred embodiment, the sensor element has substantially the same length as the aerosol - forming substrate and extends from the upstream end of the aerosol - forming substrate to the downstream end of the aerosol - forming substrate.

[0122] The sensor element is preferably in the form of a needle, strip, ribbon or sheet.

[0123] The sensor element preferably has a length of from about 5 mm to about 15 mm, such as from about 6 mm to about 12 mm, or from about 8 mm to about 10 mm.

[0124] The ratio between the length of the sensor element and the overall length of the aerosol - generating article can be from about 0.2 to about 0.35.

[0125] Preferably, the ratio between the length of the sensor element and the overall length of the aerosol - generating article is at least about 0.22, more preferably at least about 0.24, even more preferably at least about 0.26. The ratio between the length of the sensor element and the overall length of the aerosol - generating article is preferably less than about 0.34, more preferably less than about 0.32, even more preferably less than about 0.3.

[0126] The ratio between the length of the sensor element and the overall length of the aerosol - generating article can be from about 0.22 to about 0.34, more preferably from about 0.24 to about 0.34, even more preferably from about 0.26 to about 0.34. The ratio between the length of the sensor element and the overall length of the aerosol - generating article can be from about 0.22 to about 0.32, more preferably from about 0.24 to about 0.32, even more preferably from about 0.26 to about 0.32. In a further embodiment, the ratio between the length of the sensor element and the overall length of the aerosol - generating article is preferably from about 0.22 to about 0.3, more preferably from about 0.24 to about 0.3, even more preferably from about 0.26 to about 0.3.

[0127] In a particularly preferred embodiment, the ratio of the length of the sensor element to the overall length of the aerosol - generating article is about 0.27.

[0128] The sensor element preferably has a width of from about 1 mm to about 5 mm.

[0129] The sensor element generally may have a thickness of from about 0.01 mm to about 2 mm, such as from about 0.5 mm to about 2 mm. The thickness of the sensor element may be from about 10 microns to about 500 microns, more preferably from about 10 microns to about 100 microns.

[0130] If the sensor element has a constant cross-section, such as a circular cross-section, it has a preferred width or diameter of from about 1 mm to about 5 mm.

[0131] If the sensor element has the form of a strip or sheet, the strip or sheet preferably has a rectangular shape, the rectangular shape having a width preferably of from about 2 mm to about 8 mm, more preferably of from about 3 mm to about 5 mm. By way of example, a sensor element in the form of a strip or sheet may have a width of about 4 mm.

[0132] If the sensor element has the form of a strip or sheet, the strip or sheet preferably has a rectangular shape and a thickness of from about 0.03 mm to about 0.15 mm, more preferably of from about 0.05 mm to about 0.09 mm. By way of example, a sensor element in the form of a strip or blade may have a thickness of about 0.07 mm.

[0133] In a preferred embodiment, the elongate sensor element is in the form of a strip or blade, preferably has a rectangular shape, and has a thickness of from about 55 microns to about 65 microns.

[0134] More preferably, the elongate sensor element has a thickness of from about 57 microns to about 63 microns. Even more preferably, the elongate sensor element has a thickness of from about 58 microns to about 62 microns. In a particularly preferred embodiment, the elongate sensor element has a thickness of about 60 microns.

[0135] Preferably, the elongate sensor element has a length that is the same as or shorter than the length of the aerosol-forming substrate. Preferably, the elongate sensor element has the same length as the aerosol-forming substrate.

[0136] The sensor element may be formed from any material capable of being inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. Preferably the sensor element comprises a metal or carbon.

[0137] Preferred sensor elements may include or consist of ferromagnetic materials such as ferromagnetic alloys, ferritic iron, or ferromagnetic or stainless steel. Suitable sensor elements may be or include aluminum. Preferred sensor elements may be formed from a 400 series stainless steel such as grade 410, 420, or 430 stainless steel. Different materials will dissipate different amounts of energy when positioned within an electromagnetic field having similar frequency and field strength values.

[0138] Accordingly, parameters such as the material type, length, width, and thickness of the sensor element may all be varied to achieve a desired power dissipation within a known electromagnetic field. Preferred sensor elements may be heated to temperatures in excess of 250 degrees Celsius.

[0139] Suitable sensor elements may include a non-metallic core having a metal layer disposed thereon such as metal tracks formed on the surface of a ceramic core. The sensor element may have an outer protective layer such as a ceramic or glass protective layer encapsulating the sensor element. The sensor element may include a protective coating formed from glass, ceramic, or an inert metal that is formed on the core of the sensor element material.

[0140] The sensor element may be a multi-material sensor element and may include a first sensor element material and a second sensor element material. The first sensor element material is disposed in intimate physical contact with the second sensor element material. The second sensor element material preferably has a Curie temperature below 500 degrees Celsius. The first sensor element material is preferably primarily used to heat the sensor element when the sensor element is placed in a fluctuating electromagnetic field. Any suitable material may be used. For example, the first sensor element material may be aluminum or may be an iron-containing material such as stainless steel. The second sensor element material is preferably primarily used to indicate when the sensor element has reached a specific temperature which is the Curie temperature of the second sensor element material. The Curie temperature of the second sensor element material may be used to regulate the temperature of the entire sensor element during operation. Accordingly, the Curie temperature of the second sensor element material should be below the ignition point of the aerosol-forming substrate. Suitable materials for the second sensor element material may include nickel and certain nickel alloys.

[0141] By providing a sensing element having at least a first sensing element material and a second sensing element material, wherein the second sensing element material has a Curie temperature and the first sensing element material does not have a Curie temperature, or the first sensing element material and the second sensing element material have a first Curie temperature and a second Curie temperature that are different from each other, the heating and temperature control of the aerosol-forming substrate can be separated. The first sensing element material is preferably a magnetic material having a Curie temperature above 500 degrees Celsius. From the perspective of heating efficiency, it is desirable that the Curie temperature of the first sensing element material be above any maximum temperature to which the sensing element should be able to heat. The second Curie temperature can preferably be selected to be below 400 degrees Celsius, preferably below 380 degrees Celsius, or below 360 degrees Celsius. Preferably, the second sensing element material is a selected magnetic material having a second Curie temperature that is substantially the same as the desired maximum heating temperature. That is, preferably, the second Curie temperature is approximately the same as the temperature to which the sensing element should be heated in order to generate an aerosol from the aerosol-forming substrate. The second Curie temperature can, for example, be in the range of 200 degrees Celsius to 400 degrees Celsius, or between 250 degrees Celsius and 360 degrees Celsius. The second Curie temperature of the second sensing element material can, for example, be selected such that after heating by a sensing element having a temperature equal to the second Curie temperature, the overall average temperature of the aerosol-forming substrate does not exceed 240 degrees Celsius.

[0142] The aerosol-forming substrate can have a length between about 10 millimeters and about 15 millimeters. The aerosol-forming substrate can have a length between about 11 millimeters and about 12 millimeters.

[0143] The aerosol-forming substrate can include tobacco cut filler.

[0144] The aerosol-forming substrate can include tobacco cast leaf.

[0145] The aerosol-forming substrate can be an aggregated sheet of homogenized tobacco material. The aggregated sheet of homogenized tobacco material can extend across substantially the entire cross-sectional area of the strip.

[0146] The aggregated sheet of homogenized tobacco material can have a grammage of 100 g / m 2 to about 300 g / m 2 .

[0147] The aggregated sheet of homogenized tobacco material can have a thickness between 50 μm and about 300 μm.

[0148] The aggregated sheet of homogenized tobacco material can be a curled and aggregated sheet of homogenized tobacco material. The curled and aggregated sheet of homogenized tobacco material can have a plurality of ridges or corrugations that are substantially parallel to the longitudinal axis of the strip.

[0149] In some preferred embodiments, the aerosol-forming substrate comprises homogenized plant material, preferably homogenized tobacco material.

[0150] As used herein, the term "homogenized plant material" encompasses any plant material formed by the coalescence of plant particles. For example, a sheet or web of homogenized tobacco material for use in the aerosol-forming substrate of the present invention can be formed by coalescing particles of tobacco material obtained by grinding, milling or crushing plant material and optionally one or more of tobacco leaves and tobacco stalks. The homogenized plant material can be produced by casting, extrusion, papermaking processes or any other suitable process known in the art.

[0151] The homogenized plant material can be provided in any suitable form. For example, the homogenized plant material can be in the form of one or more sheets. As used herein, the term "sheet" describes a sheet-like element having a width and length substantially greater than its thickness. The homogenized plant material can be in the form of a plurality of pellets or granules. The homogenized plant material can be in the form of a plurality of strands, strips or pieces. As used herein, the term "strand" describes an elongate element of material having a length significantly greater than its width and thickness. The term "strand" should be considered to include strips, pieces and any other homogenized plant material having a similar form. Strands of homogenized plant material can be formed from sheets of homogenized plant material, for example by cutting or shredding, or by other methods, such as by extrusion methods.

[0152] Due to the splitting or cracking of sheets of homogenized plant material during the formation of the aerosol-forming substrate, for example due to curling, strands can be formed in situ within the aerosol-forming substrate. Strands of homogenized plant material within the aerosol-forming substrate can be separated from each other. At least some of the strands of homogenized plant material within the aerosol-forming substrate can be at least partially connected to one or more adjacent strands along the length of the strand. For example, adjacent strands can be connected by one or more fibers. As described above, this can occur, for example, in the case where strands are formed due to the splitting of sheets of homogenized plant material during the production of the aerosol-forming substrate.

[0153] Preferably, the aerosol - forming substrate is in the form of one or more sheets of homogenized plant material. The one or more sheets of homogenized plant material can be produced by a casting process. The one or more sheets of homogenized plant material can be produced by a papermaking process. Each of the one or more sheets as described herein can individually have a thickness between 100 micrometers and 600 micrometers, preferably between 150 micrometers and 300 micrometers, and most preferably between 200 micrometers and 250 micrometers. The individual thickness refers to the thickness of an individual sheet, while the combined thickness refers to the total thickness of all the sheets that make up the aerosol - forming substrate. For example, if the aerosol - forming substrate is formed from two individual sheets, the combined thickness is the sum of the thicknesses of the two individual sheets or the measured thickness of the two sheets in the case where the two sheets are stacked in the aerosol - forming substrate.

[0154] Each of the one or more sheets as described herein can individually have a grammage of about 100 g / m 2 to about 300 g / m 2 per square meter.

[0155] Each of the one or more sheets as described herein can individually have a density of about 0.3 g / cm 3 to about 1.3 g / cm 3 and preferably about 0.7 g / cm 3 to about 1.0 g / cm 3 of density.

[0156] In embodiments where the aerosol - forming substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of one or more aggregated sheets. As used herein, the term "aggregated" means that the sheets of homogenized plant material are wound, folded, or otherwise compressed or contracted substantially transverse to the cylindrical axis of the rod or strip.

[0157] One or more sheets of homogenized plant material can be aggregated transversely with respect to their longitudinal axes and delimited with a wrapper to form a continuous strip or rod.

[0158] One or more sheets of homogenized plant material can be advantageously curled or otherwise treated. As used herein, the term "curled" means that the sheet has a plurality of substantially parallel ridges or corrugations. Alternatively or in addition to curling, one or more sheets of homogenized plant material can be embossed, debossed, perforated, or otherwise deformed to provide a texture on one or both sides of the sheet.

[0159] Preferably, each sheet of homogenized plant material is rollable such that it has a plurality of ridges or corrugations that are substantially parallel to the longitudinal axis of the strip. This treatment advantageously facilitates the aggregation of the rolled sheets of homogenized plant material to form an aerosol-forming substrate. Preferably, one or more sheets of homogenized plant material can be aggregated. It should be appreciated that the rolled sheets of homogenized plant material may alternatively or additionally have a plurality of ridges or corrugations that are substantially parallel and are disposed at an acute or obtuse angle to the longitudinal axis of the strip. The sheet can be rolled to such an extent that the integrity of the sheet is disrupted at the plurality of parallel ridges or corrugations, causing the material to separate and resulting in the formation of fragments, strands or strips of homogenized plant material.

[0160] One or more sheets of homogenized plant material can be cut into strands as described above. The aerosol-forming substrate can include a plurality of strands of homogenized plant material. The strands can be used to form a rod. Typically, the width of these strands is about 5 mm, or about 4 mm, or about 3 mm, or about 2 mm or less. The length of the strands can be greater than about 5 mm, between about 5 mm and about 15 mm, about 8 mm to about 12 mm, or about 12 mm. Preferably, the strands have substantially the same length as each other. The length of the strands can be determined by the manufacturing process, whereby the strip is cut into shorter rods and the length of the strands corresponds to the length of the rod. The strands may be fragile, which may lead to breakage, especially during transportation. In such cases, the length of some strands can be less than the length of the rod.

[0161] The plurality of strands preferably extend substantially longitudinally along the length of the aerosol-forming substrate and are aligned with the longitudinal axis. Preferably, the plurality of strands are thus aligned substantially parallel to each other.

[0162] The homogenized plant material can include up to about 95 wt% plant particles by dry weight. Preferably, the homogenized plant material includes up to about 90 wt% plant particles, more preferably up to about 80 wt% plant particles, more preferably up to about 70 wt% plant particles, more preferably up to about 60 wt% plant particles, more preferably up to about 50 wt% plant particles by dry weight.

[0163] For example, the homogenized plant material can include plant particles between about 2.5 wt% and about 95 wt%, or between about 5 wt% and about 90 wt%, or between about 10 wt% and about 80 wt%, or between about 15 wt% and about 70 wt%, or between about 20 wt% and about 60 wt%, or between about 30 wt% and about 50 wt% by dry weight.

[0164] The homogenized plant material can be a homogenized tobacco material including tobacco particles. A sheet of the homogenized tobacco material for such embodiments can have a tobacco content of at least about 40% by weight, more preferably at least about 50% by weight, more preferably at least about 70% by weight, and most preferably at least about 90% by weight on a dry weight basis.

[0165] The term "tobacco particle" describes particles of any plant member of the genus Nicotiana. The term "tobacco particle" includes ground or shredded tobacco leaves, ground or shredded tobacco stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the handling, processing, and transportation of tobacco. In preferred embodiments, the tobacco particles are substantially all derived from tobacco leaves. In contrast, isolated nicotine and nicotine salts are compounds derived from tobacco but are not considered tobacco particles for the purposes of the present invention and are not included in the percentage of particulate plant material.

[0166] The tobacco particles can be prepared from one or more tobacco plants. Any type of tobacco can be used in the blend. Examples of tobacco types that can be used include, but are not limited to, sun-cured tobacco, flue-cured tobacco, burley tobacco, Maryland tobacco, Oriental tobacco, Virginia tobacco, and other specialty tobaccos.

[0167] Flue-curing is a method of curing tobacco, especially used with Virginia tobacco. During the curing process, heated air is circulated through tightly packed tobacco. During the first stage, the tobacco leaves turn yellow and wilt. During the second stage, the laminae of the leaves are completely dried. During the third stage, the stems are completely dried.

[0168] Burley tobacco plays an important role in many tobacco blends. Burley tobacco has a distinctive flavor and aroma and also has the ability to absorb large amounts of casing.

[0169] Oriental tobacco is a tobacco with small leaves and high aromatic quality. However, the flavor of Oriental tobacco is milder than, for example, the flavor of burley tobacco. Therefore, a relatively small proportion of Oriental tobacco is typically used in tobacco blends.

[0170] Kasturi, Madura, and Jatim are all subtypes of sun-cured tobacco that can be used. Preferably, Kasturi tobacco and flue-cured tobacco can be used in the mixture to produce tobacco particles. Thus, the tobacco particles in the particulate plant material can include a mixture of Kasturi tobacco and flue-cured tobacco.

[0171] The tobacco particles may have a nicotine content of at least about 2.5% by weight on a dry weight basis. More preferably, the tobacco particles may have a nicotine content of at least about 3% by weight, even more preferably at least about 3.2% by weight, even more preferably at least about 3.5% by weight, and most preferably at least about 4% by weight on a dry weight basis.

[0172] The homogenized plant material may include tobacco particles in combination with non - tobacco plant flavor particles. Preferably, the non - tobacco plant flavor particles are selected from one or more of the following: ginger particles, rosemary particles, eucalyptus particles, clove particles, and star anise particles. Preferably, in such embodiments, the homogenized plant material includes at least about 2.5% by weight of non - tobacco plant flavor particles on a dry weight basis, wherein the remainder of the plant particles is tobacco particles. Preferably, the homogenized plant material includes at least about 4% by weight of non - tobacco plant flavor particles, more preferably at least about 6% by weight of non - tobacco plant flavor particles, more preferably at least about 8% by weight of non - tobacco plant flavor particles, and more preferably at least about 10% by weight of non - tobacco plant flavor particles. Preferably, the homogenized plant material includes at most about 20% by weight of non - tobacco plant flavor particles, more preferably at most about 18% by weight of non - tobacco plant flavor particles, more preferably at most about 16% by weight of non - tobacco plant flavor particles.

[0173] The weight ratio of non - tobacco plant flavor particles to tobacco particles in the particulate plant material forming the homogenized plant material may vary depending on the desired flavor characteristics and composition of the aerosol produced by the aerosol - forming matrix during use. Preferably, the homogenized plant material includes a weight ratio of non - tobacco plant flavor particles to tobacco particles of at least 1:30, more preferably at least 1:20, more preferably at least 1:10, and most preferably at least 1:5 on a dry weight basis.

[0174] The homogenized plant material preferably includes no more than 95% by weight of particulate plant material on a dry weight basis. Thus, the particulate plant material is typically combined with one or more other components to form the homogenized plant material.

[0175] The homogenized plant material may further include a binder to modify the mechanical properties of the particulate plant material, where the binder is included in the homogenized plant material during manufacture as described herein. Suitable exogenous binders are known to those skilled in the art and include, but are not limited to: gums such as guar gum, xanthan gum, gum arabic, and locust bean gum; cellulose binders such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, and ethyl cellulose; polysaccharides such as starch; organic acids such as alginic acid; conjugate base salts of organic acids such as sodium alginate, agar, and pectin; and combinations thereof. Preferably, the binder includes guar gum.

[0176] The binder may be present in an amount of about 1 wt% to about 10 wt%, preferably in an amount of about 2 wt% to about 5 wt%, based on the dry weight of the homogenized plant material.

[0177] The homogenized plant material may further include one or more lipids to facilitate the diffusion of volatile components (e.g., aerosol formers, gingerols, and nicotine), where the lipids are included in the homogenized plant material during manufacture as described herein. Suitable lipids included in the homogenized plant material include, but are not limited to: medium-chain triglycerides, cocoa butter, palm oil, palm kernel oil, mango oil, shea butter, soybean oil, cottonseed oil, coconut oil, hydrogenated coconut oil, candelilla wax, carnauba wax, shellac, sunflower wax, sunflower oil, rice bran, and Revel A; and combinations thereof.

[0178] The homogenized plant material may further include a pH regulator.

[0179] The homogenized plant material may further include fibers to modify the mechanical properties of the homogenized plant material, where the fibers are included in the homogenized plant material during manufacture as described herein. Suitable exogenous fibers for inclusion in the homogenized plant material are known in the art and include fibers formed from non-tobacco and non-ginger materials, including but not limited to: cellulose fibers; softwood fibers; hardwood fibers; jute fibers; and combinations thereof. Exogenous fibers derived from tobacco and / or ginger may also be added. Any fibers added to the homogenized plant material are not considered to form part of the "particulate plant material" as defined above. Prior to inclusion in the homogenized plant material, the fibers may be treated by suitable methods known in the art, including but not limited to: mechanical pulping; refining; chemical pulping; bleaching; sulfate pulping; and combinations thereof. The fibers generally have a length greater than their width.

[0180] Suitable fibers typically have a length greater than 400 microns and less than or equal to 4 millimeters, preferably in the range of 0.7 millimeters to 4 millimeters. Preferably, the fibers are present in an amount of about 2% to about 15% by weight, most preferably at least about 4% by weight, based on the dry weight of the matrix.

[0181] The aerosol-forming matrix, particularly homogenized plant material, may also include one or more aerosol-forming agents. Upon volatilization, the aerosol-forming agent can convey other volatile compounds released from the aerosol-forming matrix upon heating, such as nicotine and flavorings, in the aerosol. Suitable aerosol-forming agents included in homogenized plant material are known in the art and include, but are not limited to: polyols such as triethylene glycol, propylene glycol, 1,3-butanediol, and glycerol; esters of polyols such as glycerol mono-, di-, or triacetate; and aliphatic esters of mono-, di-, or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

[0182] The aerosol-forming matrix, particularly homogenized plant material, may have an aerosol-forming agent content between about 5% and about 30% by dry weight, such as between about 10% and about 25% by dry weight, or between about 15% and about 20% by dry weight.

[0183] For example, if the matrix is intended for use in an aerosol-generating article of an electrically operated aerosol-generating system having a heating element, it may preferably have an aerosol-forming agent content between about 5% and about 30% by dry weight. If the matrix is intended for use in an aerosol-generating article of an electrically operated aerosol-generating system having a heating element, the aerosol-forming agent is preferably glycerol.

[0184] The aerosol-forming matrix, particularly homogenized plant material, may have an aerosol-forming agent content of about 1% to about 5% by dry weight. For example, if the matrix is intended for use in an aerosol-generating article in which the aerosol-forming agent is held in a reservoir separate from the matrix, the matrix may have an aerosol-forming agent content greater than 1% and less than about 5%. In such an embodiment, the aerosol-forming agent volatilizes upon heating, and the stream of the aerosol-forming agent contacts the aerosol-forming matrix to entrain flavorings from the aerosol-forming matrix in the aerosol.

[0185] An aerosol-forming substrate, particularly homogenized plant material, may have an aerosol-forming agent content of from about 30% to about 45% by weight. This relatively high level of aerosol-forming agent is particularly suitable for aerosol-forming substrates intended to be heated at temperatures below 275 degrees Celsius. In such embodiments, the homogenized plant material preferably further comprises a cellulose ether in an amount of from about 2% to about 10% by dry weight and additional cellulose in an amount of from about 5% to about 50% by dry weight. It has been found that the use of a combination of cellulose ether and additional cellulose provides particularly effective aerosol delivery when used in an aerosol-forming substrate having an aerosol-forming agent content between 30% and 45% by weight.

[0186] Suitable cellulose ethers include, but are not limited to, methylcellulose, hydroxypropylmethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose, and carboxymethylcellulose (CMC). In a particularly preferred embodiment, the cellulose ether is carboxymethylcellulose.

[0187] As used herein, the term "additional cellulose" encompasses any cellulose material incorporated into the homogenized plant material that does not originate from non-tobacco plant particles or tobacco particles provided in the homogenized plant material. Thus, in addition to non-tobacco plant material or tobacco material, additional cellulose is incorporated into the homogenized plant material as a separate and distinct source of cellulose from any cellulose inherently provided within the non-tobacco plant particles or tobacco particles. Additional cellulose typically originates from a plant different from the non-tobacco plant particles or tobacco particles. Preferably, the additional cellulose is in the form of an inert cellulose material that is sensorially inert and thus substantially does not affect the sensory characteristics of the aerosol generated from the aerosol-forming substrate. For example, the additional cellulose is preferably an odorless and tasteless material.

[0188] The additional cellulose may include cellulose powder, cellulose fibers, or a combination thereof.

[0189] The aerosol-forming agent may act as a humectant in the aerosol-forming substrate.

[0190] The wrapper defining the homogenized plant material strip may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in particular embodiments of the present invention are known in the art and include, but are not limited to: cigarette paper; and filter tip segment wrappers. Suitable non-paper wrappers for use in particular embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco material. In certain preferred embodiments, the wrapper may be formed from a laminate comprising a plurality of layers. Preferably, the wrapper is formed from an aluminum co-laminated sheet. In cases where the aerosol-forming substrate is to be ignited rather than heated in the intended manner, the use of an aluminum-containing co-laminated sheet advantageously prevents combustion of the aerosol-forming substrate.

[0191] In some preferred embodiments, the aerosol-forming substrate comprises a gel composition, and the gel composition comprises an alkaloid compound. In particularly preferred embodiments, the aerosol-forming substrate comprises a gel composition, and the gel composition comprises nicotine.

[0192] Preferably, the gel composition comprises an alkaloid compound; an aerosol former; and at least one gelling agent. Preferably, at least one gelling agent forms a solid medium, and glycerol is dispersed in the solid medium, wherein the alkaloid is dispersed in the glycerol. Preferably, the gel composition is in a stable gel phase.

[0193] Advantageously, a stable gel composition comprising nicotine provides a predictable composition form during storage or transportation from the manufacturer to the consumer. A stable gel composition comprising nicotine substantially retains its shape. A stable gel composition comprising nicotine substantially does not release a liquid phase during storage or transportation from the manufacturer to the consumer. A stable gel composition comprising nicotine can provide a simple consumable design. The consumable may not have to be designed to hold a liquid, and thus a wider range of materials and container configurations can be considered.

[0194] The gel composition described herein can be combined with an aerosol-generating device to provide a nicotine aerosol to the lungs at an inhalation rate or air flow rate within the range of inhalation rates or air flow rates of a conventional smoking manner. The aerosol-generating device can continuously heat the gel composition. The consumer can take multiple inhalations or "puffs", and a certain amount of nicotine aerosol is delivered with each "puff". When preferably heated in a continuous manner, the gel composition is capable of delivering a high nicotine / low total particulate matter (TPM) aerosol to the consumer.

[0195] The phrase "stable gel phase" or "stable gel" refers to a gel that substantially retains its shape and mass when exposed to various environmental conditions. When exposed to standard temperature and pressure while the relative humidity changes from about 10% to about 60%, the stable gel may substantially not release (sweat) or absorb moisture. For example, when exposed to standard temperature and pressure while the relative humidity changes from about 10% to about 60%, the stable gel may substantially retain its shape and mass.

[0196] The gel composition may comprise an alkaloid compound. The gel composition may comprise one or more alkaloids.

[0197] The term "alkaloid compound" refers to any one of a class of naturally occurring organic compounds that contain one or more basic nitrogen atoms. Generally, alkaloids contain at least one nitrogen atom in an amine-type structure. This or another nitrogen atom in the alkaloid compound molecule can be used as a base in an acid-base reaction. One or more of the nitrogen atoms in most alkaloid compounds are part of a ring system, such as a heterocycle. In nature, alkaloid compounds are mainly present in plants and are particularly common in certain families of flowering plants. However, some alkaloid compounds are present in animal species and fungi. In the present disclosure, the term "alkaloid compound" refers to alkaloid compounds of natural origin and synthetically manufactured alkaloid compounds.

[0198] The gel composition preferably includes an alkaloid compound selected from nicotine, anatabine, and combinations thereof.

[0199] Preferably, the gel composition includes nicotine.

[0200] The term "nicotine" refers to nicotine and nicotine derivatives, such as free-base nicotine, nicotine salts, etc.

[0201] The gel composition preferably includes from about 0.5 wt% to about 10 wt% of an alkaloid compound. The gel composition can include from about 0.5 wt% to about 5 wt% of an alkaloid compound. Preferably, the gel composition includes from about 1 wt% to about 3 wt% of an alkaloid compound. The gel composition can preferably include from about 1.5 wt% to about 2.5 wt% of an alkaloid compound. The gel composition can preferably include about 2 wt% of an alkaloid compound. The alkaloid compound component of the gel formulation can be the most volatile component in the gel formulation. In some aspects, water can be the most volatile component in the gel formulation, and the alkaloid compound component of the gel formulation can be the second most volatile component in the gel formulation. In some aspects, water can be the most volatile component in the gel formulation, and the alkaloid compound component of the gel formulation can be the second most volatile component in the gel formulation.

[0202] Preferably, the gel composition contains nicotine. Nicotine can be added to the composition in free-base form or in salt form. The gel composition includes from about 0.5 wt% to about 10 wt% of nicotine, or from about 0.5 wt% to about 5 wt% of nicotine. Preferably, the gel composition includes from about 1 wt% to about 3 wt% of nicotine, or from about 1.5 wt% to about 2.5 wt% of nicotine, or about 2 wt% of nicotine. The nicotine component of the gel formulation can be the most volatile component in the gel formulation. In some aspects, water can be the most volatile component in the gel formulation, and the nicotine component of the gel formulation can be the second most volatile component in the gel formulation.

[0203] The gel composition preferably comprises an aerosol - forming agent. Desirably, the aerosol - forming agent is substantially resistant to thermal degradation at the operating temperature of the relevant aerosol - generating device. Suitable aerosol - forming agents include, but are not limited to: polyols such as triethylene glycol, 1,3 - butanediol, and glycerol; esters of polyols such as glycerol mono -, di - or tri - acetate; and aliphatic esters of mono -, di - or poly - carboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate. The polyol or a mixture thereof may be one or more of triethylene glycol, 1,3 - butanediol, glycerol (glycerin or propane - 1,2,3 - triol), or polyethylene glycol. The aerosol - forming agent is preferably glycerol.

[0204] The gel composition may comprise a majority of the aerosol - forming agent. The gel composition may comprise a mixture of water and an aerosol - forming agent, wherein the aerosol - forming agent forms the majority (by weight) of the gel composition. The aerosol - forming agent may form at least about 50% by weight of the gel composition. The aerosol - forming agent may form at least about 60% by weight or at least about 65% by weight or at least about 70% by weight of the gel composition. The aerosol - forming agent may form from about 70% by weight to about 80% by weight of the gel composition. The aerosol - forming agent may form from about 70% by weight to about 75% by weight of the gel composition.

[0205] The gel composition may comprise a majority of glycerol. The gel composition may comprise a mixture of water and glycerol, wherein glycerol forms the majority (by weight) of the gel composition. Glycerol may form at least about 50% by weight of the gel composition. Glycerol may form at least about 60% by weight or at least about 65% by weight or at least about 70% by weight of the gel composition. Glycerol may form from about 70% by weight to about 80% by weight of the gel composition. Glycerol may form from about 70% by weight to about 75% by weight of the gel composition.

[0206] The gel composition preferably comprises at least one gelling agent. Preferably, the gel composition comprises a gelling agent in an amount in the range of from about 0.4% by weight to about 10% by weight. More preferably, the composition comprises a gelling agent in the range of from about 0.5% by weight to about 8% by weight. More preferably, the composition comprises a gelling agent in the range of from about 1% by weight to about 6% by weight. More preferably, the composition comprises a gelling agent in the range of from about 2% by weight to about 4% by weight. More preferably, the composition comprises a gelling agent in the range of from about 2% by weight to about 3% by weight.

[0207] The term "gelling agent" refers to a compound that, when added in an amount of about 0.3% by weight to a 50% water / 50% glycerol mixture, homogeneously forms a solid medium or supporting matrix that results in a gel. Gelling agents include, but are not limited to, hydrogen - bond cross - linking gelling agents and ion - cross - linking gelling agents.

[0208] The gelling agent may include one or more biopolymers. The biopolymers may be formed from polysaccharides.

[0209] Biopolymers include, for example, gellan gum (natural, low acyl gellan gum, high acyl gellan gum, preferably low acyl gellan gum), xanthan gum, alginate (alginic acid), agar, guar gum, and the like. The composition may preferably include xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include two biopolymers in substantially equal weights. The composition may include three biopolymers in substantially equal weights.

[0210] Preferably, the gel composition includes at least about 0.2% by weight of a hydrogen bond crosslinked gelling agent. The gel composition preferably includes at least about 0.2% by weight of an ionic crosslinked gelling agent. Most preferably, the gel composition includes at least about 0.2% by weight of a hydrogen bond crosslinked gelling agent and at least about 0.2% by weight of an ionic crosslinked gelling agent. The gel composition may include from about 0.5% to about 3% by weight of a hydrogen bond crosslinked gelling agent and from about 0.5% to about 3% by weight of an ionic crosslinked gelling agent, or from about 1% to about 2% by weight of a hydrogen bond crosslinked gelling agent and from about 1% to about 2% by weight of an ionic crosslinked gelling agent. The hydrogen bond crosslinked gelling agent and the ionic crosslinked gelling agent may be present in the gel composition in substantially equal amounts by weight.

[0211] The term "hydrogen bond crosslinked gelling agent" refers to a gelling agent that forms non-covalent crosslinking bonds or physical crosslinking bonds via hydrogen bonds. A hydrogen bond is an electrostatic dipole-dipole attraction type between molecules, rather than a covalent bond with a hydrogen atom. It is generated by the attraction between a hydrogen atom covalently bonded to a highly electronegative atom (such as an N, O, or F atom) and another highly electronegative atom.

[0212] The hydrogen bond crosslinked gelling agent may include one or more of galactomannan, gelatin, agarose, or konjac gum or agar. The hydrogen bond crosslinked gelling agent may preferably include agar.

[0213] The gel composition preferably includes a hydrogen bond crosslinked gelling agent in the range of about 0.3% to about 5% by weight. Preferably, the composition includes a hydrogen bond crosslinked gelling agent in the range of about 0.5% to about 3% by weight. Preferably, the composition includes a hydrogen bond crosslinked gelling agent in the range of about 1% to about 2% by weight.

[0214] The gel composition may include galactomannan in the range of about 0.2% to about 5% by weight. Preferably, the galactomannan may be in the range of about 0.5% to about 3% by weight. Preferably, the galactomannan may be in the range of about 0.5% to about 2% by weight. Preferably, the galactomannan may be in the range of about 1% to about 2% by weight.

[0215] The gel composition may include gelatin in the range of about 0.2 wt% to about 5 wt%. Preferably, the gelatin may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the gelatin may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the gelatin may be in the range of about 1 wt% to about 2 wt%.

[0216] The gel composition may include agarose in the range of about 0.2 wt% to about 5 wt%. Preferably, the agarose may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the agarose may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the agarose may be in the range of about 1 wt% to about 2 wt%.

[0217] The gel composition may include konjac gum in the range of about 0.2 wt% to about 5 wt%. Preferably, the konjac gum may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the konjac gum may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the konjac gum may be in the range of about 1 wt% to about 2 wt%.

[0218] The gel composition may include agar in the range of about 0.2 wt% to about 5 wt%. Preferably, the agar may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the agar may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the agar may be in the range of about 1 wt% to about 2 wt%.

[0219] The term "ionic cross - linking gelling agent" refers to a gelling agent that forms non - covalent cross - links or physical cross - links through ionic bonds. Ionic cross - linking involves the association of polymer chains through non - covalent interactions. A cross - linked network is formed when polyvalent molecules of opposite charges are electrostatically attracted to each other to form a cross - linked polymer network.

[0220] The ionic cross - linking gelling agent may include low - acyl gellan gum, pectin, κ - carrageenan, ι - carrageenan, or alginate. The ionic cross - linking gelling agent may preferably include low - acyl gellan gum.

[0221] The gel composition may include an ionic cross - linking gelling agent in the range of about 0.3 wt% to about 5 wt%. Preferably, the composition includes an ionic cross - linking gelling agent in the range of about 0.5 wt% to about 3 wt%. Preferably, the composition includes an ionic cross - linking gelling agent in the range of about 1 wt% to about 2 wt%.

[0222] The gel composition may include low - acyl gellan gum in the range of about 0.2 wt% to about 5 wt%. Preferably, the low - acyl gellan gum may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the low - acyl gellan gum may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the low - acyl gellan gum may be in the range of about 1 wt% to about 2 wt%.

[0223] The gel composition may include pectin in the range of about 0.2 wt% to about 5 wt%. Preferably, the pectin may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the pectin may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the pectin may be in the range of about 1 wt% to about 2 wt%.

[0224] The gel composition may include kappa-carrageenan in the range of about 0.2 wt% to about 5 wt%. Preferably, the kappa-carrageenan may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the kappa-carrageenan may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the kappa-carrageenan may be in the range of about 1 wt% to about 2 wt%.

[0225] The gel composition may include iota-carrageenan in the range of about 0.2 wt% to about 5 wt%. Preferably, the iota-carrageenan may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the iota-carrageenan may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the iota-carrageenan may be in the range of about 1 wt% to about 2 wt%.

[0226] The gel composition may include alginate in the range of about 0.2 wt% to about 5 wt%. Preferably, the alginate may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the alginate may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the alginate may be in the range of about 1 wt% to about 2 wt%.

[0227] The gel composition may include a hydrogen bond cross-linked gelling agent and an ionic cross-linked gelling agent in a ratio of about 3:1 to about 1:3. Preferably, the gel composition may include a hydrogen bond cross-linked gelling agent and an ionic cross-linked gelling agent in a ratio of about 2:1 to about 1:2. Preferably, the gel composition may include a hydrogen bond cross-linked gelling agent and an ionic cross-linked gelling agent in a ratio of about 1:1.

[0228] The gel composition may further include a thickener. The thickener in combination with the hydrogen bond cross-linked gelling agent and the ionic cross-linked gelling agent surprisingly appears to support the solid medium and maintain the gel composition even when the gel composition includes a high level of glycerol.

[0229] The term "thickener" refers to a compound that, when uniformly added in an amount of 0.3% by weight to a mixture of 50% by weight water / 50% by weight glycerol at 25 °C, increases the viscosity without causing gel formation and the mixture remains or retains fluidity. Preferably, the thickener refers to a compound that, when uniformly added in an amount of 0.3% by weight to a mixture of 50% by weight water / 50% by weight glycerol at 25 °C, increases the viscosity to at least 50 cPs, preferably at least 200 cPs, preferably at least 500 cPs, preferably at least 1000 cPs at a shear rate of 0.1 s-1 without causing gel formation and the mixture remains or retains fluidity. Preferably, the thickener refers to a compound that, when uniformly added in an amount of 0.3% by weight to a mixture of 50% by weight water / 50% by weight glycerol at 25 °C, increases the viscosity by at least 2-fold, or at least 5-fold, or at least 10-fold, or at least 100-fold compared to before addition at a shear rate of 0.1 s-1 without causing gel formation and the mixture remains or retains fluidity.

[0230] The viscosity values described herein can be measured using a Brookfield RVT viscometer with a rotating disk RV#2 spindle at 25 °C and a rotational speed of 6 revolutions per minute (rpm).

[0231] The gel composition preferably includes a thickener in the range of about 0.2% to about 5% by weight. Preferably, the composition includes a thickener in the range of about 0.5% to about 3% by weight. Preferably, the composition includes a thickener in the range of about 0.5% to about 2% by weight. Preferably, the composition includes a thickener in the range of about 1% to about 2% by weight.

[0232] The thickener can include one or more of xanthan gum, carboxymethyl cellulose, microcrystalline cellulose, methyl cellulose, gum arabic, guar gum, λ-carrageenan, or starch. The thickener can preferably include xanthan gum.

[0233] The gel composition can include xanthan gum in the range of about 0.2% to about 5% by weight. Preferably, the xanthan gum can be in the range of about 0.5% to about 3% by weight. Preferably, the xanthan gum can be in the range of about 0.5% to about 2% by weight. Preferably, the xanthan gum can be in the range of about 1% to about 2% by weight.

[0234] The gel composition can include carboxymethyl cellulose in the range of about 0.2% to about 5% by weight. Preferably, the carboxymethyl cellulose can be in the range of about 0.5% to about 3% by weight. Preferably, the carboxymethyl cellulose can be in the range of about 0.5% to about 2% by weight. Preferably, the carboxymethyl cellulose can be in the range of about 1% to about 2% by weight.

[0235] The gel composition may include microcrystalline cellulose in the range of about 0.2 wt% to about 5 wt%. Preferably, the microcrystalline cellulose may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the microcrystalline cellulose may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the microcrystalline cellulose may be in the range of about 1 wt% to about 2 wt%.

[0236] The gel composition may include methylcellulose in the range of about 0.2 wt% to about 5 wt%. Preferably, the methylcellulose may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the methylcellulose may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the methylcellulose may be in the range of about 1 wt% to about 2 wt%.

[0237] The gel composition may include gum arabic in the range of about 0.2 wt% to about 5 wt%. Preferably, the gum arabic may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the gum arabic may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the gum arabic may be in the range of about 1 wt% to about 2 wt%.

[0238] The gel composition may include guar gum in the range of about 0.2 wt% to about 5 wt%. Preferably, the guar gum may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the guar gum may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the guar gum may be in the range of about 1 wt% to about 2 wt%.

[0239] The gel composition may include λ-carrageenan in the range of about 0.2 wt% to about 5 wt%. Preferably, the λ-carrageenan may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the λ-carrageenan may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the λ-carrageenan may be in the range of about 1 wt% to about 2 wt%.

[0240] The gel composition may include starch in the range of about 0.2 wt% to about 5 wt%. Preferably, the starch may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the starch may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the starch may be in the range of about 1 wt% to about 2 wt%.

[0241] The gel composition may further include divalent cations. Preferably, the divalent cations include calcium ions such as calcium lactate in solution. For example, divalent cations (such as calcium ions) may help form the gel of a composition including a gelling agent such as an ion-crosslinked gelling agent. The ionic effect may help gel formation. The divalent cations may be present in the gel composition in the range of about 0.1 wt% to about 1 wt% or about 0.5 wt%.

[0242] The gel composition may further include an acid. The acid may include a carboxylic acid. The carboxylic acid may include a keto group. Preferably, the carboxylic acid may include a keto group having less than about 10 carbon atoms or less than about 6 carbon atoms or less than about 4 carbon atoms, such as levulinic acid or lactic acid. Preferably, the carboxylic acid has three carbon atoms (such as lactic acid). Lactic acid surprisingly improves the stability of the gel composition even more than similar carboxylic acids. The carboxylic acid may assist in gel formation. During storage, the carboxylic acid may reduce the change in the concentration of alkaloid compounds in the gel composition. During storage, the carboxylic acid may reduce the change in the nicotine concentration in the gel composition.

[0243] The gel composition may include a carboxylic acid in the range of about 0.1 wt% to about 5 wt%. Preferably, the carboxylic acid may be in the range of about 0.5 wt% to about 3 wt%. Preferably, the carboxylic acid may be in the range of about 0.5 wt% to about 2 wt%. Preferably, the carboxylic acid may be in the range of about 1 wt% to about 2 wt%.

[0244] The gel composition may include lactic acid in the range of about 0.1 wt% to about 5 wt%. Preferably, lactic acid may be in the range of about 0.5 wt% to about 3 wt%. Preferably, lactic acid may be in the range of about 0.5 wt% to about 2 wt%. Preferably, lactic acid may be in the range of about 1 wt% to about 2 wt%.

[0245] The gel composition may include levulinic acid in the range of about 0.1 wt% to about 5 wt%. Preferably, levulinic acid may be in the range of about 0.5 wt% to about 3 wt%. Preferably, levulinic acid may be in the range of about 0.5 wt% to about 2 wt%. Preferably, levulinic acid may be in the range of about 1 wt% to about 2 wt%.

[0246] The gel composition preferably includes some water. When the gel composition includes some water, the gel composition is more stable. Preferably, the gel composition includes at least about 1 wt%, or at least about 2 wt%, or at least about 5 wt% of water. Preferably, the gel composition includes at least about 10 wt% or at least about 15 wt% of water.

[0247] Preferably, the gel composition includes water between about 8 wt% and 32 wt%. Preferably, the gel composition includes about 15 wt% to about 25 wt% of water. Preferably, the gel composition includes about 18 wt% to about 22 wt% of water. Preferably, the gel composition includes about 20 wt% of water.

[0248] Preferably, the aerosol-forming substrate includes about 150 mg to about 350 mg of the gel composition.

[0249] Preferably, in embodiments comprising a gel composition, the aerosol - forming substrate comprises a porous medium carrying the gel composition. The advantage of a porous medium carrying a gel composition is that the gel composition is retained within the porous medium, and this can assist in the manufacture, storage, or transportation of the gel composition. It can help maintain the desired shape of the gel composition, especially during manufacture, transportation, or use.

[0250] The term "porous" as used herein refers to a material that provides a plurality of pores or openings that permit air to pass through the material.

[0251] The porous medium can be any suitable porous material capable of accommodating or retaining the gel composition. Desirably, the porous medium can allow the gel composition to move therein. In certain embodiments, the porous medium comprises natural materials, synthetic or semi - synthetic materials, or combinations thereof. In certain embodiments, the porous medium comprises sheet materials, foams, or fibers, such as loose fibers; or combinations thereof. In certain embodiments, the porous medium comprises woven, non - woven, or extruded materials, or combinations thereof. Preferably, the porous medium comprises cotton, paper, viscose, PLA, or cellulose acetate, or combinations thereof. Preferably, the porous medium comprises a sheet material, such as cotton or cellulose acetate. In a particularly preferred embodiment, the porous medium comprises a sheet made of cotton fibers.

[0252] The porous medium can be crimped or shredded. In a preferred embodiment, the porous medium is crimped. In an alternative embodiment, the porous medium comprises shredded porous medium. The crimping or shredding process can be before or after loading the gel composition.

[0253] Crimping the sheet has the benefit of improving the structure to allow passageways through the structure. Channels through the crimped sheet material assist in loading the gel, holding the gel, and also assist in fluid passing through the crimped sheet material. Thus, using a crimped sheet material as the porous medium has advantages.

[0254] Shredding enables a high surface - area - to - volume ratio of the medium to readily absorb the gel.

[0255] In some embodiments, the sheet is a composite material. Preferably, the sheet is porous. The sheet material can assist in manufacturing a tubular element comprising the gel. The sheet material can assist in introducing an active agent into a tubular element comprising the gel. The sheet material can contribute to stabilizing the structure of a tubular element comprising the gel. The sheet material can assist in transporting or storing the gel. Using the sheet material can achieve or contribute to adding structure to the porous medium, such as by crimping the sheet material.

[0256] The porous medium can be a filament. The filament can comprise, for example, cotton, paper, or acetate silk. The filament can also carry the gel, as can any other porous medium. The advantage of using a filament as the porous medium is that it can assist in easy manufacture.

[0257] The filament can carry the gel by any known means. The filament can simply be coated with the gel, or the filament can be impregnated with the gel. In manufacture, the filament can be impregnated with the gel and stored ready for inclusion in the assembly of the tubular element.

[0258] Preferably, in embodiments where the first element comprises the gel composition, as described above, the tubular element has a length of less than 10 millimeters. The use of such a relatively short tubular element in combination with the gel composition can optimize aerosol delivery to the consumer.

[0259] The aerosol-generating article can include a capsule. The aerosol-forming substrate can be disposed within the capsule. During use, the consumer can rupture the capsule and draw on the aerosol-generating article, which causes the capsule to move within the aerosol-generating article and release the aerosol-forming substrate to form an aerosol that can be inhaled and delivered to the consumer's lungs. As used herein, the term "rupture" means providing at least one opening in the capsule to allow the aerosol-forming substrate within the capsule to leave the capsule. For example, the consumer can insert a rupturing element through the distal end of the aerosol-generating article to rupture the capsule. As another example, the capsule can be ruptured by the consumer applying a force to the capsule, such as with a finger.

[0260] The capsule can include a capsule shell for encapsulating the aerosol-forming substrate. The capsule can be any suitable pharmaceutical capsule, such as a hard capsule. The capsule shell can be made from a gelling agent such as gelatin and / or a polysaccharide. The capsule shell can be formed from hydroxypropyl methylcellulose (HPMC). The capsule shell can contain a plasticizer, such as glycerol or sorbitol.

[0261] As used herein, the term "pharmaceutically active ingredient" means an ingredient that alters one or more chemical or physiological functions of a cell, tissue, organ, or organism.

[0262] The aerosol-forming substrate disposed within the capsule can be a dry powder. The dry powder can include a pharmaceutically active ingredient. The pharmaceutically active ingredient can be nicotine.

[0263] According to one aspect of the present invention, there is provided an electrically heated aerosol-generating system comprising an aerosol-generating article as described herein and an aerosol-generating device, the aerosol-generating device including an electrical element for heating the aerosol-forming substrate.

[0264] The aerosol-generating device can include a power source. The power source can be configured to supply power to the electrical element. The power source can be any suitable power source, such as a DC voltage source, such as a battery. In one embodiment, the power source is a lithium-ion battery. Alternatively, the power source can be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery such as a lithium-cobalt, lithium-iron-phosphate, lithium titanate, or lithium-polymer battery.

[0265] An aerosol-generating device may include a chamber for receiving an aerosol-generating article.

[0266] The electrical component may be a heating element. The electrical component may be disposed inside or around the chamber of the aerosol-generating device. The electrical component may be an inductor, such as an induction coil.

[0267] The aerosol-generating device may include an internal heating element, such as a needle or sheet at least partially inserted into the aerosol-forming substrate. The internal heating element may be configured to be inserted into a radially central position of the aerosol-forming substrate.

[0268] The aerosol-generating device may include an external heating element positioned around the perimeter of the chamber of the aerosol-generating device. The external heating element may be in any suitable form. For example, the external heating element may be in the form of one or more flexible heating foils on a dielectric substrate (e.g., polyimide). The flexible heating foil may be shaped to conform to the perimeter of the chamber. Alternatively, the external heating element may take the form of a metal grid, a flexible printed circuit board, a moulded interconnect device (MID), a ceramic heating element, a flexible carbon fibre heating element, or may be formed on a suitable moulded substrate using coating techniques, such as plasma vapour deposition.

[0269] It should be appreciated that any feature described with reference to one aspect of the present invention or disclosure is equally applicable to any other aspect of the present invention or disclosure.

[0270] The present invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0271] Ex1. An aerosol-generating article, the aerosol-generating article comprising a plurality of elements assembled in the form of a strip, the plurality of elements comprising:

[0272] An aerosol-forming substrate;

[0273] A first tubular element, the first tubular element including an upstream end wall defining a first opening for allowing fluid communication between the interior and the exterior of the first tubular element; and

[0274] A second tubular element, the second tubular element including a second tubular element end wall defining a second opening for allowing fluid communication between the interior and the exterior of the second tubular element;

[0275] Wherein the first tubular element is positioned upstream of the second tubular element and adjacent to the second tubular element within the strip.

[0276] Ex2. The aerosol-generating article according to Ex1, wherein a downstream end of the first tubular element is in physical contact with an upstream end of the second tubular element.

[0277] Ex3. The aerosol-generating article according to Ex1 or Ex2, wherein the first tubular element and the second tubular element are positioned upstream of the aerosol-forming substrate.

[0278] Ex4. The aerosol-generating article according to any one of Ex1 to Ex3, wherein the first tubular element is the most upstream element of the aerosol-generating article.

[0279] Ex5. The aerosol-generating article according to any one of Ex1 to Ex4, wherein the first tubular element is positioned at the most upstream end of the aerosol-generating article.

[0280] Ex6. The aerosol-generating article according to any one of Ex1 to Ex5, wherein the second tubular element is positioned adjacent to the upstream end of the aerosol-forming substrate.

[0281] Ex7. The aerosol-generating article according to any one of Ex1 to Ex6, wherein the second tubular element is in physical contact with the upstream end of the aerosol-forming substrate.

[0282] Ex8. The aerosol-generating article according to Ex7, wherein an end wall of the second tubular element is in physical contact with the upstream end of the aerosol-forming substrate.

[0283] Ex9. The aerosol-generating article according to Ex1 or Ex2, wherein the first tubular element and the second tubular element are positioned downstream of the aerosol-forming substrate.

[0284] Ex10. The aerosol-generating article according to Ex9, wherein the second tubular element is the most downstream element of the aerosol-generating article.

[0285] Ex11. The aerosol-generating article according to Ex9 or Ex10, wherein the second tubular element is positioned at the most downstream end of the aerosol-generating article.

[0286] Ex12. The aerosol-generating article according to any one of Ex9 to Ex11, wherein the first tubular element is positioned adjacent to the downstream end of the aerosol-forming substrate.

[0287] Ex13. The aerosol-generating article according to any one of Ex9 to Ex12, wherein the first tubular element is in physical contact with the downstream end of the aerosol-forming substrate.

[0288] Ex14. The aerosol-generating article according to Ex13, wherein an upstream end wall of the first tubular element is in physical contact with a downstream end of the aerosol-forming substrate.

[0289] Ex15. The aerosol-generating article according to any one of Ex9 to Ex14, wherein any element positioned downstream of the second tubular element has a draw resistance of approximately 0 mmH2O.

[0290] Ex16. The aerosol-generating article according to any one of Ex9 to Ex15, wherein there is no filter element made of cellulose acetate positioned downstream of the second tubular element.

[0291] Ex17. The aerosol-generating article according to any one of Ex9 to Ex16, wherein there is no filter element positioned downstream of the second tubular element.

[0292] Ex18. The aerosol-generating article according to any one of Ex9 to Ex17, wherein a second tubular element end wall of the second tubular element is positioned less than 15 millimeters from a downstream end of the aerosol-generating article.

[0293] Ex19. The aerosol-generating article according to any one of Ex9 to Ex18, wherein a second tubular element end wall of the second tubular element is positioned less than 10 millimeters from a downstream end of the aerosol-generating article.

[0294] Ex20. The aerosol-generating article according to any one of Ex9 to Ex19, wherein a second tubular element end wall of the second tubular element is positioned less than 5 millimeters from a downstream end of the aerosol-generating article.

[0295] Ex21. The aerosol-generating article according to any one of Ex1 to Ex20, wherein the upstream end wall is formed by a first folded end portion, preferably wherein the first folded end portion is a flanged end portion.

[0296] Ex22. The aerosol-generating article according to any one of Ex1 to Ex21, wherein the second tubular element end wall is formed by a second folded end portion, preferably wherein the second folded end portion is a flanged end portion.

[0297] Ex23. The aerosol-generating article according to any one of Ex1 to Ex22, wherein there is no end wall at a downstream end of the first tubular element.

[0298] Ex24. The aerosol-generating article according to any one of Ex1 to Ex23, wherein there is no end wall at an upstream end of the second tubular element.

[0299] Ex25. An aerosol-generating article according to any one of Ex1 to Ex24, wherein the first tubular element includes a first cavity extending from an upstream end wall of the first tubular element to a downstream end of the first tubular element.

[0300] Ex26. The aerosol-generating article according to Ex25, wherein the first cavity is empty.

[0301] Ex27. The aerosol-generating article according to Ex25 or Ex26, wherein the first cavity has a diameter of at least about 50% of the diameter of the first tubular element.

[0302] Ex28. The aerosol-generating article according to any one of Ex25 to Ex27, wherein the first cavity has a diameter of at least about 60% of the diameter of the first tubular element.

[0303] Ex29. The aerosol-generating article according to any one of Ex25 to Ex28, wherein the first cavity has a diameter of at least about 70% of the diameter of the first tubular element.

[0304] Ex30. The aerosol-generating article according to any one of Ex25 to Ex29, wherein the first cavity has a diameter of at least about 80% of the diameter of the first tubular element.

[0305] Ex31. The aerosol-generating article according to any one of Ex25 to Ex30, wherein the first cavity has a diameter of at least about 90% of the diameter of the first tubular element.

[0306] Ex32. The aerosol-generating article according to any one of Ex25 to Ex31, wherein the first cavity has a diameter of at least about 95% of the diameter of the first tubular element.

[0307] Ex33. The aerosol-generating article according to any one of Ex25 to Ex32, wherein the diameter of the first cavity increases between the upstream end wall of the first tubular element and the downstream end of the first tubular element.

[0308] Ex34. The aerosol-generating article according to any one of Ex25 to Ex32, wherein the diameter of the first cavity increases from the upstream end wall of the first tubular element to the downstream end of the first tubular element.

[0309] Ex35. The aerosol-generating article according to any one of Ex25 to Ex32, wherein the diameter of the first cavity decreases between the upstream end wall of the first tubular element and the downstream end of the first tubular element.

[0310] Ex36. An aerosol-generating article according to any one of Ex25 to Ex32, wherein the diameter of the first chamber decreases from the upstream end wall of the first tubular element to the downstream end of the first tubular element.

[0311] Ex37. An aerosol-generating article according to any one of Ex25 to Ex32, wherein the diameter of the first chamber is substantially constant between the upstream end wall of the first tubular element and the downstream end of the first tubular element.

[0312] Ex38. An aerosol-generating article according to Ex37, wherein the diameter of the chamber is substantially constant from the upstream end wall of the first tubular element to the downstream end of the first tubular element.

[0313] Ex39. An aerosol-generating article according to any one of Ex1 to Ex38, wherein the second tubular element includes a second chamber extending from the upstream end of the second tubular element to the downstream end of the second tubular element.

[0314] Ex40. An aerosol-generating article according to any one of Ex39, wherein the second chamber is empty.

[0315] Ex41. An aerosol-generating article according to Ex39 or Ex40, wherein the diameter of the second chamber is at least about 50% of the diameter of the second tubular element.

[0316] Ex42. An aerosol-generating article according to any one of Ex39 to Ex41, wherein the diameter of the second chamber is at least about 60% of the diameter of the second tubular element.

[0317] Ex43. An aerosol-generating article according to any one of Ex39 to Ex42, wherein the diameter of the second chamber is at least about 70% of the diameter of the second tubular element.

[0318] Ex44. An aerosol-generating article according to any one of Ex39 to Ex43, wherein the diameter of the second chamber is at least about 80% of the diameter of the second tubular element.

[0319] Ex45. An aerosol-generating article according to any one of Ex39 to Ex44, wherein the diameter of the second chamber is at least about 90% of the diameter of the second tubular element.

[0320] Ex46. An aerosol-generating article according to any one of Ex39 to Ex45, wherein the diameter of the second chamber is at least about 95% of the diameter of the second tubular element.

[0321] Ex47. An aerosol-generating article according to any one of Ex39 to Ex46, wherein the diameter of the second chamber increases between the upstream end and the downstream end of the second tubular element.

[0322] Ex48. An aerosol-generating article according to any one of Ex39 to Ex46, wherein the diameter of the second chamber increases from the upstream end to the downstream end of the second tubular element.

[0323] Ex49. An aerosol-generating article according to any one of Ex39 to Ex46, wherein the diameter of the second chamber decreases between the upstream end and the downstream end of the second tubular element.

[0324] Ex50. An aerosol-generating article according to any one of Ex39 to Ex46, wherein the diameter of the second chamber decreases from the upstream end to the downstream end of the second tubular element.

[0325] Ex51. An aerosol-generating article according to any one of Ex39 to Ex46, wherein the diameter of the second chamber is substantially constant between the upstream end and the downstream end of the second tubular element.

[0326] Ex52. An aerosol-generating article according to Ex51, wherein the diameter of the second chamber is substantially constant from the upstream end to the downstream end of the second tubular element.

[0327] Ex53. An aerosol-generating article according to any one of Ex1 to Ex52, comprising a continuous chamber extending from the upstream end wall of the first tubular element to the downstream end of the second tubular element.

[0328] Ex54. An aerosol-generating article according to Ex53, wherein the continuous chamber has a uniform diameter along the entire length of the continuous chamber.

[0329] Ex55. An aerosol-generating article according to any one of Ex1 to Ex54, wherein the first tubular element has a length greater than the length of the second tubular element.

[0330] Ex56. An aerosol-generating article according to any one of Ex1 to Ex54, wherein the first tubular element has a length less than the length of the second tubular element.

[0331] Ex57. An aerosol-generating article according to any one of Ex1 to Ex54, wherein the first tubular element has a length substantially equal to the length of the second tubular element.

[0332] Ex58. An aerosol-generating article according to any one of Ex1 to Ex57, wherein the first opening is radially aligned with the second opening.

[0333] Ex59. An aerosol-generating article according to any one of Ex1 to Ex57, wherein the first opening is radially offset from the second opening.

[0334] Ex60. An aerosol-generating article according to any one of Ex1 to Ex59, wherein the first opening is located at the radial center.

[0335] Ex61. An aerosol-generating article according to any one of Ex1 to Ex59, wherein the second opening is located at the radial center.

[0336] Ex62. An aerosol-generating article according to any one of Ex1 to Ex60, wherein the first opening has an equivalent diameter equal to or greater than about 10% of the diameter of the upstream end wall.

[0337] Ex63. An aerosol-generating article according to any one of Ex1 to Ex61, wherein the first opening has an equivalent diameter equal to or greater than about 20% of the diameter of the upstream end wall.

[0338] Ex64. An aerosol-generating article according to any one of Ex1 to Ex62, wherein the first opening has an equivalent diameter equal to or greater than about 30% of the diameter of the upstream end wall.

[0339] Ex65. An aerosol-generating article according to any one of Ex1 to Ex63, wherein the first opening has an equivalent diameter equal to or greater than about 40% of the diameter of the upstream end wall.

[0340] Ex66. An aerosol-generating article according to any one of Ex1 to Ex64, wherein the first opening has an equivalent diameter equal to or greater than about 50% of the diameter of the upstream end wall.

[0341] Ex67. An aerosol-generating article according to any one of Ex1 to Ex65, wherein the first opening has an equivalent diameter between about 1 mm and about 3 mm.

[0342] Ex68. An aerosol-generating article according to any one of Ex1 to Ex66, wherein the second opening has an equivalent diameter equal to or greater than about 10% of the diameter of the end wall of the second tubular element.

[0343] Ex69. An aerosol-generating article according to any one of Ex1 to Ex67, wherein the second opening has an equivalent diameter equal to or greater than about 20% of the diameter of the end wall of the second tubular element.

[0344] Ex70. An aerosol-generating article according to any one of Ex1 to Ex68, wherein the second opening has an equivalent diameter that is equal to or greater than about 30% of the diameter of the end wall of the second tubular element.

[0345] Ex71. An aerosol-generating article according to any one of Ex1 to Ex69, wherein the second opening has an equivalent diameter that is equal to or greater than about 40% of the diameter of the end wall of the second tubular element.

[0346] Ex72. An aerosol-generating article according to any one of Ex1 to Ex70, wherein the second opening has an equivalent diameter that is equal to or greater than about 50% of the diameter of the end wall of the second tubular element.

[0347] Ex73. An aerosol-generating article according to any one of Ex1 to Ex71, wherein the second opening has an equivalent diameter between about 1 mm and about 3 mm.

[0348] Ex74. An aerosol-generating article according to any one of Ex1 to Ex72, wherein the first opening has an equivalent diameter that is less than the equivalent diameter of the second opening.

[0349] Ex75. An aerosol-generating article according to any one of Ex1 to Ex72, wherein the first opening has an equivalent diameter that is less than the equivalent diameter of the second opening.

[0350] Ex76. An aerosol-generating article according to any one of Ex1 to Ex72, wherein the first opening has an equivalent diameter that is substantially equal to the equivalent diameter of the second opening.

[0351] Ex77. An aerosol-generating article according to any one of Ex1 to Ex76, wherein the upstream end wall defines a plurality of openings for allowing fluid communication between the interior and the exterior of the first tubular element.

[0352] Ex78. An aerosol-generating article according to any one of Ex1 to Ex77, wherein the end wall of the second tubular element defines a plurality of openings for allowing fluid communication between the interior and the exterior of the second tubular element.

[0353] Ex79. An aerosol-generating article according to any one of Ex1 to Ex78, wherein the number of openings defined in the upstream end wall is greater than the number of openings defined in the end wall of the second tubular element.

[0354] Ex80. An aerosol-generating article according to any one of Ex1 to Ex79, further comprising a pre-rod located upstream of the aerosol-forming substrate.

[0355] Ex81. The aerosol-generating article according to Ex80, wherein the front rod is the most upstream element of the aerosol-generating article.

[0356] Ex82. The aerosol-generating article according to Ex80 or Ex81, wherein the front rod is in physical contact with the upstream end of the aerosol-forming substrate.

[0357] Ex83. The aerosol-generating article according to any one of Ex80 to Ex82, wherein the front rod is a hollow element, for example, the front rod is in the form of a tube.

[0358] Ex84. The aerosol-generating article according to any one of Ex80 to Ex83, wherein the front rod is made of cellulose acetate, for example, the front rod is a hollow cellulose acetate tube.

[0359] Ex85. The aerosol-generating article according to any one of Ex80 to Ex84, wherein the front rod has a length between about 2 millimeters and about 8 millimeters.

[0360] Ex86. The aerosol-generating article according to any one of Ex80 to Ex85, wherein the front rod has a length of about 5 millimeters.

[0361] Ex87. The aerosol-generating article according to any one of Ex1 to Ex86, wherein the upstream end wall of the first tubular element comprises a hydrophobic coating.

[0362] Ex88. The aerosol-generating article according to any one of Ex1 to Ex87, wherein the second tubular element end wall of the second tubular element comprises a hydrophobic coating.

[0363] Ex89. The aerosol-generating article according to any one of Ex1 to Ex88, wherein the first tubular element comprises a hydrophobic coating.

[0364] Ex90. The aerosol-generating article according to any one of Ex1 to Ex89, wherein the second tubular element comprises a hydrophobic coating.

[0365] Ex91. The aerosol-generating article according to any one of Ex1 to Ex90, wherein one or both of the first tubular element and the second tubular element are formed of a paper material.

[0366] Ex92. The aerosol-generating article according to any one of Ex1 to Ex91, wherein one or both of the first tubular element and the second tubular element are formed of cardboard.

[0367] Ex93. The aerosol-generating article according to any one of Ex1 to Ex92, wherein the wall thickness of the tubular wall of the first tubular element is greater than the wall thickness of the tubular wall of the second tubular element.

[0368] Ex94. An aerosol-generating article according to any one of Ex1 to Ex92, wherein the wall thickness of the tubular wall of the first tubular element is less than the wall thickness of the tubular wall of the second tubular element.

[0369] Ex95. An aerosol-generating article according to any one of Ex1 to Ex94, wherein the wall thickness is between about 150 micrometers and about 600 micrometers.

[0370] Ex96. An aerosol-generating article according to any one of Ex1 to Ex95, comprising an outer wrapper that at least defines the first tubular element and the second tubular element.

[0371] Ex97. The aerosol-generating article according to Ex96, wherein the outer wrapper extends from the upstream end of the first tubular element to the downstream end of the second tubular element.

[0372] Ex98. The aerosol-generating article according to Ex96 or Ex97, wherein the outer wrapper defines all the plurality of elements of the aerosol-generating article assembled in the form of a strip.

[0373] Ex99. The aerosol-generating article according to any one of Ex96 to Ex98, wherein the outer wrapper is a paper wrapper or a non-paper wrapper.

[0374] Ex100. An aerosol-generating article according to any one of Ex1 to Ex99, further comprising a ventilation zone located between the upstream end and the downstream end of the aerosol-generating article.

[0375] Ex101. The aerosol-generating article according to Ex100, wherein the ventilation zone is located downstream of the aerosol-forming substrate.

[0376] Ex102. The aerosol-generating article according to Ex100 or Ex101, wherein the ventilation zone is located at a position along the first tubular element.

[0377] Ex103. The aerosol-generating article according to Ex100 or Ex101, wherein the ventilation zone is located at a position along the second tubular element.

[0378] Ex104. The aerosol-generating article according to any one of Ex100 to Ex103, wherein the ventilation zone has a ventilation level between about 30% and about 60%.

[0379] Ex105. An aerosol-generating article according to any one of Ex1 to Ex104, further comprising a sensor element positioned in thermal contact with the aerosol-forming substrate.

[0380] Ex106. The aerosol-generating article according to Ex105, wherein the sensor element is positioned within the aerosol-forming substrate.

[0381] Ex107. The aerosol-generating article according to E105 or Ex106, wherein the sensor element is an elongate sensor element longitudinally arranged within the aerosol-forming substrate.

[0382] Ex108. The aerosol-generating article according to any one of Ex105 to Ex107, wherein the sensor element extends along a radial central axis of the aerosol-forming substrate.

[0383] Ex109. The aerosol-generating article according to any one of Ex105 to Ex108, wherein the sensor element extends from an upstream end of the aerosol-forming substrate to a downstream end of the aerosol-forming substrate.

[0384] Ex110. The aerosol-generating article according to any one of Ex105 to Ex109, wherein the sensor element is in the form of a needle, strip or sheet.

[0385] Ex111. The aerosol-generating article according to any one of Ex1 to Ex110, wherein the aerosol-forming substrate comprises shredded tobacco filler.

[0386] Ex112. The aerosol-generating article according to any one of Ex1 to Ex111, wherein the aerosol-forming substrate comprises tobacco cast leaf.

[0387] Ex113. The aerosol-generating article according to any one of Ex1 to Ex112, wherein the aerosol-forming substrate is an aggregated sheet of homogenized tobacco material.

[0388] Ex114. The aerosol-generating article according to Ex113, wherein the aggregated sheet of homogenized tobacco material extends across substantially the entire cross-sectional area of the strip.

[0389] Ex115. The aerosol-generating article according to Ex113 or Ex114, wherein the aggregated sheet of homogenized tobacco material has a grammage of from 100 g / m2 to about 300 g / m2.

[0390] Ex116. The aerosol-generating article according to any one of Ex113 to Ex115, wherein the aggregated sheet of homogenized tobacco material has a thickness between 50 μm and about 300 μm.

[0391] Ex117. The aerosol-generating article according to any one of Ex113 to Ex116, wherein the aggregated sheet of homogenized tobacco material is a curled and aggregated sheet of homogenized tobacco material.

[0392] Ex118. The aerosol-generating article according to Ex117, wherein the crimped and aggregated sheet of the homogenized tobacco material has a plurality of ridges or corrugations substantially parallel to the longitudinal axis of the strip.

[0393] Ex119. The aerosol-generating article according to any one of Ex1 to Ex118, wherein the aerosol-forming substrate comprises one or more aerosol-forming agents.

[0394] Ex120. The aerosol-generating article according to Ex119, wherein the aerosol-forming substrate has an aerosol-forming agent content of from about 10% to about 50% by dry weight.

[0395] Ex121. The aerosol-generating article according to any one of Ex1 to Ex120, wherein the aerosol-forming substrate has a length between about 10 mm and about 15 mm.

[0396] Ex122. The aerosol-generating article according to any one of Ex1 to Ex121, wherein the aerosol-forming substrate has a length between about 11 mm and about 12 mm. Description of the Drawings

[0397] Several examples will now be further described with reference to the drawings, wherein:

[0398] Figure 1 A schematic cross-sectional view of an aerosol-generating article according to a first example of the present disclosure is depicted;

[0399] Figure 2 A schematic cross-sectional view of an aerosol-generating article according to a second example of the present disclosure is depicted;

[0400] Figure 3 A schematic cross-sectional view of an aerosol-generating article according to a third example of the present disclosure is depicted;

[0401] Figure 4 A schematic cross-sectional view of an aerosol-generating article according to a fourth example of the present disclosure is depicted;

[0402] Figure 5 A schematic cross-sectional view of an aerosol-generating article according to a fifth example of the present disclosure is depicted;

[0403] Figure 6 A schematic cross-sectional view of an aerosol-generating article according to a sixth example of the present disclosure is depicted;

[0404] Figure 7 A schematic cross-sectional view of an aerosol-generating article according to a seventh example of the present disclosure is depicted;

[0405] Figure 8 Depicts a schematic cross-sectional view of an aerosol-generating article according to an eighth example of the present disclosure;

[0406] Figure 9 Depicts a schematic cross-sectional view of an aerosol-generating article according to a ninth example of the present disclosure;

[0407] Figure 10 Depicts a perspective view of a tubular element according to the present disclosure;

[0408] Figures 11A to 11D Depicts a method of forming a tubular element according to the present disclosure;

[0409] Figure 12 Depicts an alternative method of forming a tubular element according to the present disclosure. Detailed Description

[0410] Figure 1 Shows an aerosol-generating article 1 according to a first example, which includes a plurality of elements assembled in the form of a strip. The plurality of elements includes an aerosol-forming substrate 10, a first tubular element 20, and a second tubular element 30. The aerosol-generating article 1 has an overall length of about 45 millimeters and extends from a distal end 2 (or upstream end) to a mouth end 3 (or downstream end). The aerosol-generating article 1 has a diameter of about 7 millimeters.

[0411] The aerosol-generating article 1 includes an outer wrapper 40 that encloses all of the plurality of elements assembled in the form of a strip. The outer wrapper 40 is made of tipping paper and extends from the upstream end 2 of the aerosol-generating article 1 to the downstream end 3 of the aerosol-generating article 1. The outer wrapper 40 has a thickness of about 500 micrometers.

[0412] The aerosol-forming substrate 10 includes a curled and aggregated sheet of homogenized tobacco material having a plurality of ridges or corrugations extending substantially parallel to the longitudinal axis of the strip. The curled and aggregated sheet of homogenized tobacco material extends across substantially the entire cross-sectional area of the aerosol-generating article 1. The aerosol-forming substrate 10 includes an aerosol-forming agent, namely glycerol, and has an aerosol-forming agent content of about 10% by dry weight. The aerosol-forming substrate 10 has a length of about 12 millimeters. The aerosol-forming substrate 10 is substantially cylindrical and has a diameter of about 6 millimeters.

[0413] The first tubular element 20 is positioned upstream and adjacent to the second tubular element 30 within the strip. In this embodiment, the downstream end of the first tubular element 20 is spaced apart from the upstream end of the second tubular element 30 in the longitudinal direction. Thus, there is a gap 50 of blank space between the downstream end of the first tubular element 20 and the upstream end of the second tubular element 30. The gap has a length of about 4 millimeters.

[0414] The first tubular element 20 includes an upstream end wall 21 that defines a first opening 22 for allowing fluid communication between the interior and the exterior of the first tubular element 20. As will be explained in more detail with respect to Figures 11A to 11D The upstream end wall 21 is formed by a first folded end portion. The first opening 22 is located at the radial center of the upstream end wall 21 and has an equivalent diameter of approximately 3 millimeters.

[0415] The upstream end wall 21 of the first tubular element 20 is positioned adjacent to and in physical contact with the downstream end of the aerosol - forming substrate 10. The first tubular element 20 has a length of approximately 12 millimeters and extends from the downstream end of the aerosol - forming substrate 20 towards the second tubular element 30. The first tubular element 20 is cylindrical and has a diameter of approximately 6 millimeters. The first tubular element 20 is made of cardboard having a basis weight of approximately 100 grams per square meter and a thickness of approximately 1 millimeter. The first tubular element 20 has an RTD of approximately 40 millimeters H2O.

[0416] The second tubular element 30 includes a second tubular - element end wall 31 that defines a second opening 32 for allowing fluid communication between the interior and the exterior of the second tubular element 30. As can be seen, the second tubular - element end wall 31 is located at the downstream end of the second tubular element 30. Accordingly, it will be referred to as the downstream end wall. The downstream end wall 31 is formed by a second folded end portion. The second opening 32 is located at the radial center of the downstream end wall 31 and has an equivalent diameter of approximately 3 millimeters.

[0417] The second tubular element 30 is the most downstream element of the aerosol - generating article 1. However, the second tubular element 30 does not extend to the downstream end 3 of the aerosol - generating article 1. Instead, the downstream end wall 31 of the second tubular element 30 is spaced approximately 5 millimeters from the downstream end 3 of the aerosol - generating article 1. The second tubular element 30 is cylindrical and has a diameter of approximately 6 millimeters and a length of approximately 12 millimeters. The second tubular element 30 is made of cardboard having a basis weight of approximately 100 grams per square meter and a thickness of approximately 1 millimeter. The second tubular element 30 has an RTD of approximately 40 millimeters H2O.

[0418] In use, a heating element from an electrically-operated aerosol-generating device is inserted into or positioned around an aerosol-forming substrate 10, which heats the aerosol-forming substrate 10 and releases volatile compounds. A consumer sucks on the downstream end 3 of the aerosol-generating article 1 such that air is drawn through the upstream end 2 of the aerosol-generating article 1. The air is then drawn through the aerosol-forming substrate 10, where the volatile compounds released from the heated aerosol-forming substrate 10 are entrained in the air drawn through the aerosol-generating article 1. The volatile compounds and air then pass through the first opening 22 of the first tubular element 30. The volatile compounds and air are cooled and condensed within the first tubular element 20 and the second tubular element 30 by partially releasing heat to the tubular walls of the first tubular element 20 and the second tubular element 30. The cooled and condensed volatile compounds and air form an aerosol, which is drawn through the second opening 32 of the second tubular element 30 and inhaled by the consumer.

[0419] Figure 2 An aerosol-generating article 1 according to a second example is depicted, which comprises a plurality of elements assembled in the form of a strip. Figure 2 The aerosol-generating article 1 of Figure 1 is similar to the aerosol-generating article 1 of

[0420] Figure 3 and also comprises an aerosol-forming substrate 10, a first tubular element 20 and a second tubular element 30. However, the first tubular element 20 is positioned adjacent to the aerosol-forming substrate 10 but does not physically contact the downstream end of the aerosol-forming substrate 10. Instead, there is a gap 60 positioned between the downstream end of the aerosol-forming substrate 10 and the upstream end wall 21 of the first tubular element 20. The gap 60 has a length of approximately 5 millimeters. Further, the second tubular element 30 is positioned at the most downstream end of the aerosol-generating article 1. That is, the downstream end wall 31 of the second tubular element 30 is positioned at the downstream end 3 of the aerosol-generating article 1. Figure 3 An aerosol-generating article 1 according to a third example is depicted, which comprises a plurality of elements assembled in the form of a strip. Figure 1 The aerosol-generating article 1 of

[0421] Figure 4Depicts an aerosol - generating article 1 according to a fourth example, which includes a plurality of elements assembled in the form of a strip. The first tubular element 20 has a length that is less than the length of the second tubular element 30. In this embodiment, the first tubular element 20 has a length of approximately 13 millimeters, and the second tubular element 30 has a length of approximately 20 millimeters. Additionally, the first tubular element 20 has a tubular wall thickness that is less than the tubular wall thickness of the second tubular element 30. In this embodiment, the first tubular element 20 has a tubular wall thickness of approximately 0.3 millimeters, and the second tubular element 30 has a tubular wall thickness of approximately 0.6 millimeters. Further, the first opening 22 has an equivalent diameter that is greater than the equivalent diameter of the second opening 32. In this embodiment, the first opening 22 has an equivalent diameter of approximately 3.5 millimeters, and the second opening 32 has an equivalent diameter of approximately 2.5 millimeters.

[0422] Figure 5 Shows an aerosol - generating article 1 according to a fifth example, which includes a plurality of elements assembled in the form of a strip. Figure 5 The aerosol - generating article 1 of Figure 3 is similar to the aerosol - generating article 1 of Figure 5 However, the aerosol - generating article 1 of

[0423] also includes an elongate sensor element 70. The elongate sensor element 70 is positioned within the aerosol - forming substrate 10. More specifically, the sensor element 70 is arranged substantially longitudinally within the aerosol - forming substrate 10 so as to be generally parallel to the longitudinal axis of the strip. Additionally, the sensor element 70 is positioned at a radially central position within the strip and extends effectively along the longitudinal axis of the strip. The sensor element 70 extends from the upstream end to the downstream end of the aerosol - forming substrate 10. In fact, the sensor element 70 has substantially the same length as the aerosol - forming substrate 10.

[0424] The sensor element 70 is provided in the form of a strip and has a length of approximately 12 millimeters, a thickness of approximately 60 micrometers, and a width of approximately 4 millimeters.

[0425] The upstream end wall 21 of the first tubular element 20 is positioned adjacent to and in physical contact with the downstream end of the aerosol - forming substrate 10. Additionally, the width of the sensor element 70 is greater than the diameter of the first opening 22 of the first tubular element 20.

[0426] Figure 6 Depicts an aerosol - generating article 1 according to a sixth example, which includes a plurality of elements assembled in the form of a strip. Figure 6 The aerosol - generating article 1 of Figure 5 is similar to the aerosol - generating article 1 of

[0427] The front rod 70 is positioned upstream of the aerosol-forming substrate 10 and adjacent to it. The downstream end of the front rod abuts the upstream end of the aerosol-forming substrate 10. This advantageously prevents the sensor element 70 from being displaced. In addition, this ensures that the consumer does not accidentally come into contact with the heated sensor element 70 after use.

[0428] The front rod 80 is provided in the form of a cylindrical cellulose acetate rod defined by a rigid wrapper. The front rod 80 has a length of approximately 5 mm and an RTD of approximately 30 mm H2O.

[0429] The aerosol-generating article 1 includes a ventilation zone 90 disposed at a position between the first tubular element 20 and the second tubular element 30. More specifically, the ventilation zone 90 includes a plurality of perforations through the outer wrapper 40. The ventilation level of the aerosol-generating article 1 is approximately 40%.

[0430] Figure 7 The aerosol-generating article 1 according to the seventh example is depicted, which includes a plurality of elements assembled in the form of a strip. Figure 7 The aerosol-generating article 1 is similar to Figure 5 The aerosol-generating article 1, but further includes a ventilation zone 90. More specifically, the ventilation zone 90 is disposed approximately 4 mm from the downstream end of the second tubular element 30 and includes a plurality of perforations through the outer wrapper 40 and the second tubular element 30. The ventilation level of the aerosol-generating article 1 is approximately 40%.

[0431] Figure 8 The aerosol-generating article 1 according to the eighth example is depicted, which includes a plurality of elements assembled in the form of a strip. Figure 8 The aerosol-generating article 1 is similar to Figure 5 The aerosol-generating article 1. However, in Figure 8 The aerosol-generating article 1, the end wall 31 of the second tubular element is positioned at the upstream end of the second tubular element 30.

[0432] Figure 9 The aerosol-generating article 1 according to the ninth example is depicted, which includes a plurality of elements assembled in the form of a strip. The plurality of elements include a first tubular element 20, a second tubular element 30, a capsule 110 including an aerosol-forming substrate, and a third tubular element 100.

[0433] The downstream end of the first tubular element 20 is in physical contact with the upstream end of the second tubular element 30, and there is no gap between the first tubular element 20 and the second tubular element 30. Additionally, the second tubular element 30 is positioned at the most downstream end 3 of the aerosol-generating article 1.

[0434] In this example, there is a third tubular element 100 constructed in the same manner as the first tubular element 20 and the second tubular element 30. The third tubular element 100 includes an upstream end wall 101 that defines a third opening 102 for allowing fluid communication between the interior and the exterior of the third tubular element 100. The third tubular element 100 extends from the upstream end 2 of the aerosol-generating article 1 to the upstream end wall 21 of the first tubular element 20. The third tubular element 100 includes a lumen 104 that extends from the upstream end wall 101 of the third tubular element 100 to the downstream end.

[0435] Compared with the first to eighth examples, in the ninth example, the aerosol-generating article 1 includes a capsule 110 that includes an aerosol-forming substrate in the form of an inhalable dry powder. During use, the consumer inserts a rupturing element, such as a needle, through the third opening 102 to rupture the capsule 110. The upstream end wall 21 of the first tubular element 20 restricts the downstream movement of the capsule 110, thereby facilitating the process of rupturing the capsule. Once the capsule is ruptured, when the consumer sucks on the downstream end 3 of the aerosol-generating article 1, the aerosol-forming substrate within the capsule is released.

[0436] Figure 10 A perspective view of the first tubular element 20 according to Figure 1 is depicted. The upstream end wall 21 extends substantially transverse to the longitudinal direction of the aerosol-generating article 1 and the longitudinal direction of the first tubular element 20.

[0437] Figures 11A to 11D The first tubular element 20 of the aerosol-generating article according to the present disclosure is shown through different stages of its formation. Thus, these illustrations show a method of forming a first tubular element (such as Figure 1 the first tubular element 20). A similar method is used to form the second tubular element of the present disclosure.

[0438] As shown by Figure 11A , the method starts with providing a tubular element precursor 200 that includes a tubular body 201 that defines a lumen 203 that extends along a longitudinal axis from a first end of the tubular body to a second end of the tubular body; and a first end portion 202 that is adjacent to and integrally formed with the first end of the tubular body 201.

[0439] To form the upstream end wall 21, a folding force is applied to the tubular element precursor 200 to cause the first end portion 202 to bend about a folding point 204. The folding force causes the first end portion 202 to bend inward relative to the tubular body 201 (as shown by Figure 11B and 11Cas indicated by the dashed curved arrow in) and deflected towards the cavity 203. The folding force is continued to be applied until the first end portion 202 has been folded at an angle greater than 90 degrees (as measured relative to the wall of the tubular body). Then the folding force is released. The inherent elastic properties of the paper material (such as paper, cardboard or carton board) of the tubular element precursor 200 will cause the first end portion 202 to partially recover along its folding path such that the first end portion 202 reaches a position where it extends substantially transverse to the longitudinal direction of the tubular body 201. This position is shown by Figure 11D shown.

[0440] Figure 12 shows an alternative method for forming a tubular element according to the present disclosure. In a first step 301, a cellulose material such as paper is mixed with water to form a pulp. Generally, the water has a temperature of about 40 degrees Celsius to 70 degrees Celsius. In a second step 302, the pulp is placed in a mold to produce the desired shape of the tubular element. In a third step 303, the molded pulp is discharged from the mold and dried to remove moisture from the molded pulp, thereby forming the tubular element.

[0441] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing quantities, amounts, percentages, etc. should be understood to be modified in all instances by the term "about". Additionally, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therebetween, whether or not specifically enumerated herein. Thus, in this context, the number A is understood as A ± 5%A. In this context, the number A can be regarded as including values within the general standard error for the measurement of the property modified by the number A. In some cases where used in the appended claims, the number A can deviate from the percentage recited above, provided that the amount by which A deviates does not substantially affect the basic and novel features of the claimed invention. Additionally, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therebetween, whether or not specifically enumerated herein.

Claims

1. An aerosol-generating article, the aerosol-generating article comprising a plurality of elements assembled in the form of a strip, the plurality of elements comprising: An aerosol-forming substrate; A first tubular element including an upstream end wall defining a first opening for allowing fluid communication between the interior and the exterior of the first tubular element; And A second tubular element including a second tubular element end wall defining a second opening for allowing fluid communication between the interior and the exterior of the second tubular element; Wherein the first tubular element is positioned upstream of and adjacent to the second tubular element within the strip.

2. The aerosol-generating article according to claim 1, wherein a downstream end of the first tubular element is in physical contact with an upstream end of the second tubular element.

3. The aerosol-generating article according to claim 1 or 2, wherein the end wall of the second tubular element is located at a downstream end of the second tubular element.

4. The aerosol-generating article according to any one of the preceding claims, wherein the first tubular element and the second tubular element are located downstream of the aerosol-forming substrate.

5. The aerosol-generating article according to claim 4, wherein any element located downstream of the second tubular element has a draw resistance less than that of one or more of the first tubular element, the second tubular element, or a combination of the first tubular element and the second tubular element.

6. The aerosol-generating article according to claim 4 or 5, wherein any element located downstream of the second tubular element has a draw resistance of less than about 10 mmH2O, preferably a draw resistance of about 0 mmH2O.

7. The aerosol-generating article according to any one of claims 1 to 4, wherein the second tubular element is the most downstream element of the aerosol-generating article.

8. The aerosol-generating article according to any one of the preceding claims, wherein an upstream end wall of the first tubular element is in physical contact with a downstream end of the aerosol-forming substrate.

9. The aerosol-generating article according to any one of the preceding claims, wherein the upstream end wall is formed by a first folded end portion, preferably wherein the end wall of the second tubular element is formed by a second folded end portion.

10. The aerosol-generating article according to any one of the preceding claims, wherein the first tubular element is formed of a first material and the second tubular element is formed of a second material, wherein the basis weight of the first material is greater than the basis weight of the second material.

11. The aerosol-generating article according to any one of the preceding claims, wherein the wall thickness of the tubular wall of the first tubular element is greater than the wall thickness of the tubular wall of the second tubular element.

12. The aerosol-generating article according to any one of the preceding claims, wherein one or more of the first tubular element and the second tubular element comprise a hydrophobic coating.

13. The aerosol-generating article according to any one of the preceding claims, further comprising a pre-rod located upstream of the aerosol-forming substrate.

14. The aerosol-generating article according to any one of the preceding claims, further comprising a ventilation zone located between the upstream end and the downstream end of the aerosol-generating article.

15. The aerosol-generating article according to any one of the preceding claims, further comprising a sensor element positioned in thermal contact with the aerosol-forming substrate.

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