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

Abstract

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

[0002] Aerosol-generating articles in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. Typically, 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 located in contact with, within, 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 aerosol-generating articles that have one or more elements in addition to the aerosol-forming substrate configured to perform a specific function to enhance the consumer experience. For example, WO 2013 / 120565 A2 discloses an aerosol-generating article that includes an aerosol-cooling element for cooling the aerosol formed from the substrate. In one embodiment disclosed in WO 2013 / 120565 A2, a hollow cellulose acetate tube is located immediately downstream of the aerosol-forming substrate, and an aerosol-cooling element made from a sheet of polylactic acid is located 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 an aerosol-generating article with such elements in addition to the aerosol-forming substrate can increase the cost and complexity of manufacturing the aerosol-generating article. Furthermore, these elements can have an undesirable effect on the resistance to draw (RTD) of the aerosol-generating article. For example, an aerosol-generating article with an RTD that is too low or too high can lead to an unsatisfactory consumer experience.

[0005] It would be desirable to provide an aerosol-generating article having one or more elements that can enhance the consumer experience, yet is relatively simple and inexpensive to manufacture. In particular, it would be desirable for the RTD of the elements to be controllable to provide a satisfactory RTD. Summary of the Invention

[0006] The present disclosure relates to an aerosol-generating article. The aerosol-generating article may comprise a plurality of elements assembled in the form of a rod. The plurality of elements may include an aerosol-forming substrate. The plurality of elements may also comprise a first tubular element. The first tubular element may have an upstream end wall defining a first opening for allowing fluid communication between the interior of the first tubular element and the exterior of the first tubular element. The plurality of elements may further comprise a second tubular element. The second tubular element may have a second tubular element end wall defining a second opening for allowing fluid communication between the interior of the second tubular element and the exterior of the second tubular element. The first tubular element may be positioned within the rod upstream of and adjacent to the second tubular element.

[0007] According to the present disclosure, an aerosol-generating article is provided. The aerosol-generating article comprises a plurality of elements assembled in the form of a rod. The plurality of elements comprises an aerosol-forming substrate. The plurality of elements also comprises a first tubular element having an upstream end wall defining a first opening for allowing fluid communication between the interior of the first tubular element and the exterior of the first tubular element. The plurality of elements further comprises a second tubular element having a second tubular element end wall defining a second opening for allowing fluid communication between the interior of the second tubular element and the exterior of the second tubular element. The first tubular element is positioned within the rod upstream of and adjacent to the second tubular element.

[0008] The first tubular element may be referred to as the upstream tubular element, and the second tubular element may be referred to as the downstream tubular element.

[0009] The aerosol-generating article may comprise 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 elements, each with an end wall adjacent to one another, the tubular elements can provide one or more functions to enhance the consumer experience. For example, when positioned downstream of the aerosol-forming substrate, the tubular element can function as one or more of an aerosol cooling element and a filter element. Furthermore, when positioned upstream of the aerosol-forming substrate, the tubular element can function as a front plug. This means that, because the tubular element can perform multiple different functions, the number of elements in the aerosol-generating article can be reduced, and the number of different types of elements that need to be manufactured can be reduced. Advantageously, this means that the manufacturing process can be simplified and manufacturing costs can be reduced.

[0011] Providing two separate tubular elements, each with an adjacent end wall, rather than a single tubular element with two end walls provides many benefits. For example, it has been found that providing two tubular elements, each with a single end wall, in a continuous manufacturing process can be faster and more efficient than providing a single tubular element with 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 with a different thickness. For example, a first tubular element may be exposed to high temperatures from a heating element. This means that the first tubular element may need to be made from a heat-resistant material. Meanwhile, a second tubular element may not be exposed to high temperatures 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 lead to an optimized aerosol-generating article that is relatively simple and cost-effective to manufacture.

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

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

[0014] As used herein, the term "rod" refers to an elongated element. A rod may have a substantially polygonal transverse cross-sectional shape. A circular, elliptical, or oval transverse cross-sectional shape is preferred.

[0015] As used herein, the term "elongated" refers to an element having a length dimension that is greater than its width or its diameter dimension, e.g., more than twice its width or its diameter dimension.

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

[0017] As used herein, the term "longitudinal" refers to a direction corresponding to the major longitudinal axis of the aerosol-generating article, extending between the upstream and downstream ends of the aerosol-generating article. During use, air is drawn longitudinally through the aerosol-generating article.

[0018] As used herein, the terms "upstream" and "downstream" refer to the relative location of an element of an aerosol-generating article, or a portion of an element of an aerosol-generating article, along the longitudinal axis.

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

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

[0021] As used herein, the term "tubular element" refers to an elongate element that defines a lumen or airflow passage in its longitudinal axis. Specifically, the term "tubular" is used to describe a tubular element that has a substantially cylindrical transverse cross-sectional shape and defines at least one airflow passage that establishes uninterrupted fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. However, it will be appreciated that alternative shapes (e.g., alternative transverse cross-sectional shapes) of the tubular element may be possible. For example, the tubular element may have a circular, elliptical, or oval transverse cross-section.

[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 may extend substantially transverse to the longitudinal direction of the first tubular element. The material forming the upstream end wall may be substantially impermeable.

[0023] As used herein, the term "second tubular element end wall" refers to a wall at the end of a second tubular element. The second tubular element end wall extends substantially transverse to the longitudinal axis of the second tubular element. The material forming the second tubular element end wall may be substantially impermeable.

[0024] As used herein, the term "adjacent" refers to a first element of an aerosol-generating article being longitudinally positioned next to a second element of an aerosol-generating article. In particular, this term indicates that there are no other elements of an aerosol-generating article longitudinally disposed between the first element of an aerosol-generating article and the second element of an aerosol-generating article.

[0025] As used herein, the term "filter" refers to a section or element of an aerosol-generating article that is configured to at least partially remove gas-phase or particulate-phase components, or both gas-phase 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 that are used to supply 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 the aerosol-forming substrate to generate an aerosol that can be inhaled directly into the user's lungs through the user's mouth.

[0027] In a conventional cigarette, a user lights one end of the cigarette, and the localized heat provided by the flame and oxygen in the air causes the end of the cigarette to ignite, resulting in inhalable smoke through combustion. In contrast, in a heated aerosol-generating article, the aerosol is generated by heating rather than burning an 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 the transfer of heat 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. A heated aerosol-generating article may produce fewer components that need to be filtered before inhalation by the consumer, compared to an aerosol-generating article configured so that the aerosol-forming substrate is combusted. Advantageously, this may mean that the aerosol-generating article may have fewer components downstream of the aerosol-forming substrate, leading to a cheaper aerosol-generating article to manufacture. Furthermore, this may mean that for the same size aerosol-generating article, the aerosol-generating article may be provided with a larger aerosol-forming substrate, which may provide the consumer with a longer usage session.

[0029] The downstream end of the first tubular element may be longitudinally spaced from the upstream end of the second tubular element. A gap of empty space 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, such a gap increases 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 compared to a single tubular element having the same distance between its upstream and downstream end walls, thereby reducing costs. This is particularly true when the end wall of the second tubular element is located at the downstream end of the second tubular element.

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

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

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

[0033] The first tubular element may be the most upstream element of the aerosol-generating article. The first tubular element may be located at the most upstream end of the aerosol-generating article. The upstream end wall of the first tubular element may be located at the most upstream end of the aerosol-generating article. Advantageously, this may mean that the first tubular element and the second tubular element may prevent any element of the aerosol-generating article, or a portion of any element, from exiting 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. A gap may exist 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 millimeter, at least about 2 millimeters, at least about 3 millimeters, at least about 4 millimeters, or at least about 5 millimeters. The gap may have a length of about 1 millimeter to about 5 millimeters. Such a gap may allow air exiting the downstream end of the second tubular element to move radially before passing through the aerosol-forming substrate. This is particularly true when the second tubular element end wall is positioned at the downstream end of the second tubular element. Advantageously, this may allow air to pass through the entire transverse cross-section of the aerosol-forming substrate. A gap having a length of about 1 millimeter to about 5 millimeters has been found to provide sufficient space for air to move radially without creating a large area 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 the aerosol-generating article from moving toward the downstream end of the aerosol-generating article. Furthermore, this may ensure that the heating element can be consistently positioned relative to the aerosol-forming substrate due to the restriction of movement of 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 and second tubular elements may be positioned downstream of the aerosol-forming substrate. Advantageously, the first and second tubular elements may therefore interact with one or more of the air, volatile compounds, and aerosols downstream of the aerosol-forming substrate. For example, the first and second tubular elements may act as one or more of a cooling element, a filter element, and a mouthpiece.

[0037] Many known aerosol-generating articles have a filter element located at the downstream end of the aerosol-generating article. Typically, the filter element is configured to provide the RTD of the aerosol flowing through the filter element. This means that the RTD through the filter element must be taken into account when determining the overall RTD of the aerosol-generating article. This can pose a challenge when there are several components within the aerosol-generating article and it is desirable to obtain a consistent RTD between manufactured aerosol-generating articles. In some known aerosol-generating articles, the filter element is made of cellulose acetate, which can provide the RTD.

[0038] In the aerosol-generating article of the present disclosure, there may be no filter element made of cellulose acetate positioned downstream of the second tubular element. In fact, there may be no filter element positioned downstream of the second tubular element. Additionally or alternatively, any element positioned downstream of the second tubular element may have a lower pull-out resistance than that of one or more of the first tubular element, the second tubular element, or a combination of the first and second tubular elements. For example, any element positioned downstream of the second tubular element may have a pull-out resistance of less than about 30 mmH2O, preferably less than about 20 mmH2O, more preferably less than about 10 mmH2O, or most preferably about 0 mmH2O. Advantageously, this means that it is easier to provide a consistent RTD among the aerosol-generating articles manufactured. The term "any element positioned downstream of the second tubular element" includes the absence of an element positioned 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. Therefore, no element may be 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, since fewer components need to be assembled into the aerosol-generating article. Furthermore, this may allow the second opening of the second tubular element to contract and accelerate the flow of aerosol into the consumer's mouth without impeding the aerosol accelerated by elements downstream of the second tubular element. This may provide a comfortable sensation to the consumer.

[0041] The downstream end of the second tubular element can be spaced apart from the downstream end of the aerosol-generating article. By spacing the downstream end of the second tubular element apart 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 to expand before entering the consumer's mouth. Advantageously, this may provide an aerosol stream having a greater perceived volume into the consumer's mouth, which may increase consumer satisfaction, particularly when the second tubular element end wall is located at the downstream end of the second tubular element.

[0042] The downstream end of the second tubular element may be positioned about 3 millimeters to about 20 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element may be positioned about 3 millimeters to about 15 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element may be positioned about 3 millimeters to about 10 millimeters from the downstream end of the aerosol-generating article. The downstream end of the second tubular element may be positioned about 3 millimeters to 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, and therefore the cost, of the aerosol-generating article. Advantageously, the range of about 3 millimeters to about 8 millimeters has been found to provide a good trade-off between the area for aerosol expansion and the length of the aerosol-generating article.

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

[0044] The second tubular element may be positioned at the most downstream end of the aerosol-generating article. The downstream end of the second tubular element may be positioned at the most downstream end of the aerosol-generating article. Advantageously, the second tubular element may therefore act as a mouthpiece element, supporting the lips surrounding the aerosol-generating article when the consumer inhales the aerosol-generating article.

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

[0046] The first tubular element may be located 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, as the aerosol-forming substrate dries and shrinks, or when a heating element is inserted into the aerosol-forming substrate from the upstream end of the aerosol-generating article. The first tubular element may be located 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 can be formed by a first folded end portion. The second tubular element end wall can be formed by a second folded end portion. By providing end walls formed from folded end portions of each tubular element, each tubular element can be configured to have a desired RTD through configuration of the size and shape of the end wall and opening. In particular, each tubular element and its end wall can be manufactured efficiently and quickly with satisfactory RTD and low RTD variability from article to article. Furthermore, the configuration of each tubular element and its end wall means that the RTD can be localized to a specific longitudinal location of the tubular element, i.e., the end wall, rather than being continuously distributed along the length of the tubular element. Advantageously, this means that tubular elements can be configured to have more consistent properties while maintaining a cost-effective manufacturing process.

[0048] The first folded end portion can be a flange end portion. The second folded end portion can be a flange end portion.

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

[0050] The downstream end of the first tubular element may be free of an end wall. The upstream end of the second tubular element may be free of an end wall. Alternatively, the downstream end of the second tubular element may be free of an end wall. Both the downstream end of the first tubular element and the upstream end of the second tubular element may be free of end walls. Advantageously, this may provide an unrestricted passageway 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 may provide an uninterrupted passageway for fluid flow through the first tubular element.

[0052] The first cavity may have a diameter that is at least about 50 percent of the diameter of the first tubular element. The first cavity may have a diameter that is at least about 60 percent of the diameter of the first tubular element. The first cavity may have a diameter that is at least about 70 percent of the diameter of the first tubular element. The first cavity may have a diameter that is at least about 80 percent of the diameter of the first tubular element. The first cavity may have a diameter that is at least about 90 percent of the diameter of the first tubular element. Preferably, the first cavity may have a diameter that is at least about 95 percent of the diameter of the first tubular element. Advantageously, it has been found that a first cavity diameter of at least about 50 percent 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 reduced material use can be achieved when the cavity diameter is at least about 95 percent of the diameter of the first tubular element.

[0053] The diameter of the first cavity 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 cavity may increase from the upstream end wall of the first tubular element to the downstream end of the first tubular element. Advantageously, the increase in diameter may act to slow down the flow within the first tubular element.

[0054] The diameter of the first cavity 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 cavity may decrease from the upstream end wall of the first tubular element to the downstream end of the first tubular element. Advantageously, the decrease in diameter may act to accelerate flow within the first tubular element.

[0055] The diameter of the first cavity 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 cavity 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 may help to maintain a constant flow rate throughout the first cavity, which may allow the flow to have equal contact time with all portions of the interior wall of the first cavity.

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

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

[0058] The diameter of the second cavity can 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 can 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 can 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 can 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 larger than the diameter of the second cavity. The diameter of the first cavity may be smaller 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 comprise 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 from a first cavity and a 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, or 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 that is at least about 10 percent of the length of the aerosol-generating article. The first tubular element may have a length that is at least about 20 percent of the length of the aerosol-generating article. The first tubular element may have a length that is at least about 30 percent of the length of the aerosol-generating article. The first tubular element may have a length that is at least about 40 percent of the length of the aerosol-generating article. The first tubular element may have a length that is at least about 50 percent of the length of the aerosol-generating article.

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

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

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

[0068] The first opening can be radially aligned with the second opening. That is, at least 90 percent of the cross-sectional area of ​​the first opening overlaps with the cross-sectional area of ​​the second opening when viewed in the longitudinal direction. Advantageously, this can 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 can be radially offset from the second opening. That is, the cross-sectional area of ​​the first opening does not overlap with the cross-sectional area of ​​the second opening when viewed in the longitudinal direction. Advantageously, radially offset openings can promote turbulent flow within the tubular element.

[0069] The first opening can 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, aerosol generated within the aerosol-forming substrate, such as aerosol generated near the radial central axis, can be moved radially outward as the aerosol is drawn through the aerosol-forming substrate. This is particularly advantageous in embodiments in which a heat source is positioned at a radially central position within the aerosol-forming substrate, such as a susceptor element or heating element of a device that is inserted into the substrate during use. Typically, in such embodiments, the peripheral portion of the substrate is cooler than the radially central portion of the substrate. Thus, the aerosol can be cooled as it moves radially outward within the aerosol-forming substrate. This can be particularly beneficial during a user's initial puff of the aerosol, when the majority of the aerosol can be formed near the heat source. Such an offset first opening may also prevent downstream migration of a heat source located radially centrally within the aerosol-forming substrate, particularly 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 can be radially central. That is, the periphery of the first opening can surround the radial central axis of the first tubular element, and the geometric center of the first opening can coincide with the radial central axis of the first tubular element. For example, the first opening can be at a radially central position of the upstream end wall. The second opening can be radially central. That is, the periphery of the second opening can surround the radial central axis of the second tubular element, and the geometric center of the second opening can coincide with the radial central axis of the second tubular element. For example, the second opening can be at a radially central position of the end wall of the second tubular element.

[0071] The first opening may have an equivalent diameter of about 10 percent or more of the diameter of the upstream end wall. The first opening may have an equivalent diameter of about 20 percent or more of the diameter of the upstream end wall. The first opening may have an equivalent diameter of about 30 percent or more of the diameter of the upstream end wall. The first opening may have an equivalent diameter of about 40 percent or more of the diameter of the upstream end wall. The first opening may have an equivalent diameter of about 50 percent or more of the diameter of the upstream end wall.

[0072] The first opening may have an equivalent diameter of about 1 millimeter to about 12 millimeters. The first opening may have an equivalent diameter of about 1 millimeter to about 9 millimeters. The first opening may have an equivalent diameter of about 1 millimeter to about 6 millimeters. Preferably, the first opening may have an equivalent diameter of about 1 millimeter to about 3 millimeters. Advantageously, when the first tubular element is downstream of the aerosol-forming substrate, a first opening having an equivalent diameter of about 1 millimeter to about 3 millimeters has been found to provide a good compromise between providing an acceptable RTD for the first tubular element and the ability to prevent undesirable components of the aerosol-forming substrate from migrating downstream. In particular, in these embodiments, the first opening has an equivalent diameter of about 2.5 millimeters.

[0073] The second opening may have an equivalent diameter of about 10 percent or more of the diameter of the second tubular element end wall. The second opening may have an equivalent diameter of about 20 percent or more of the diameter of the second tubular element end wall. The second opening may have an equivalent diameter of about 30 percent or more of the diameter of the second tubular element end wall. The second opening may have an equivalent diameter of about 40 percent or more of the diameter of the second tubular element end wall. The second opening may have an equivalent diameter of about 50 percent or more of the diameter of the second tubular element end wall.

[0074] The second opening may have an equivalent diameter of about 1 millimeter to about 12 millimeters. The second opening may have an equivalent diameter of about 1 millimeter to about 9 millimeters. The second opening may have an equivalent diameter of about 1 millimeter to about 6 millimeters. The second opening may have an equivalent diameter of about 1 millimeter to about 3 millimeters. Advantageously, when the second tubular element is downstream of the aerosol-forming substrate, having a second opening with an equivalent diameter of about 1 millimeter to about 3 millimeters provides a good compromise between providing an acceptable RTD in the second tubular element and filtering undesirable 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 millimeters.

[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 millimeters. 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 millimeters, and the second opening may have an equivalent diameter of about 4 millimeters. 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 millimeters, and the second opening may have an equivalent diameter of about 2 millimeters.

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

[0077] The second opening may have an equivalent diameter that is 500 percent or greater than the equivalent diameter of the first opening. The second opening may have an equivalent diameter that is 400 percent or greater than the equivalent diameter of the first opening. The second opening may have an equivalent diameter that is 300 percent or greater than the equivalent diameter of the first opening. The second opening may have an equivalent diameter that is 200 percent or greater than the equivalent diameter of the first opening. The second opening may have an equivalent diameter that is 150 percent or greater than the equivalent diameter of the first opening. The second opening may have an equivalent diameter that is 140 percent or greater than the equivalent diameter of the first opening. The second opening may have an equivalent diameter that is 130 percent or greater than the equivalent diameter of the first opening. The second opening may have an equivalent diameter that is 120 percent or greater than the equivalent diameter of the first opening. The second opening may have an equivalent diameter that is 110 percent or greater than 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 of the first tubular element 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 of the second tubular element and the exterior of the second tubular element. Advantageously, providing multiple openings rather than a single opening may allow each of the multiple openings to have a smaller 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] The aerosol-generating article may include a front plug located upstream of the aerosol-forming substrate. Advantageously, such a front plug may prevent the aerosol-forming substrate from exiting the upstream end of the aerosol-generating article. The front plug may also assist in positioning the aerosol-forming substrate at 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 front plug may also reduce the likelihood that a consumer will accidentally use an aerosol-generating article, such as a conventional cigarette, and ignite the end of the aerosol-generating article.

[0081] The front plug may be the most upstream element of the aerosol-generating article. The front plug may be in physical contact with the upstream end of the aerosol-forming substrate.

[0082] The front plug may be penetrable by the heating element so that it can contact or penetrate the aerosol-forming substrate. In such embodiments, the aerosol-forming substrate may contract and contact the heating element during the aerosol generation stage. The aerosol-forming substrate may also shrink to reduce its contact with the outer wrapper of the aerosol-generating article. Without the front plug, withdrawing the heating element from the rod may also weaken the adhesion of the aerosol-forming substrate to the cigarette paper and lead to withdrawal of the aerosol-forming substrate due to increased adhesion between the aerosol-forming substrate and the heating element. However, the front plug may facilitate removal or extraction of the heating element from the rod by limiting the movement of the aerosol-forming substrate toward the distal end of the rod. The front plug may obstruct the passage of the aerosol-forming substrate, thus preventing it from being withdrawn from the aerosol-generating article.

[0083] The front plug may be made of a filter material that allows air to be drawn through the front plug. This may allow the consumer to draw air through the aerosol-generating article via the front plug. The front plug may conveniently be formed from the same material as a conventional mouthpiece filter. For example, the front plug may be formed from cellulose acetate tow. The permeability of the front plug may be varied to help control the resistance to drawing through the aerosol-generating article. Alternatively, the front plug may be formed from a material that is impermeable to air. In such an embodiment, the aerosol-generating article may be configured to allow air to flow into the aerosol-forming substrate through a sidewall of the aerosol-generating article upstream of the aerosol-forming substrate.

[0084] The anterior plug may be a hollow element, for example, the anterior plug may be in the form of a tube.The anterior plug may be made from cellulose acetate, for example, the anterior plug may be a hollow cellulose acetate tube.

[0085] The front plug may comprise one or more materials selected from the group including ceramic, polymer, biopolymer, metal, zeolite, paper, cardboard, inert material, and inorganic material. The front plug has a diameter approximately equal to the diameter of the aerosol-generating article. Preferably, the front plug has a diameter of about 5 millimeters to about 10 millimeters. The front plug may have a front plug length of about 1 millimeter to about 10 millimeters, about 2 millimeters to about 8 millimeters, or about 4 millimeters to about 8 millimeters. The front plug may be cylindrical and may have a length of at least 2 millimeters, preferably at least 3 millimeters, or at least 4 millimeters to facilitate assembly of the aerosol-generating article. The front plug may have a length of about 5 millimeters. Advantageously, a longer plug may also provide improved cleaning by increasing the amount of front plug material available to wipe the heating element as it is withdrawn from the plug.

[0086] One or both of the first tubular element and the second tubular element may include a hydrophobic coating. The first tubular element may include a hydrophobic coating. At least a portion of the first tubular element may include a hydrophobic coating. The second tubular element may include a hydrophobic coating. At least a portion of the second tubular element may include a hydrophobic coating. The volatile compounds and air are cooled 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 degradation of the structural integrity of the first tubular element and the second tubular element by the condensed material.

[0087] The upstream end wall of the first tubular element may be provided with a hydrophobic coating. The second tubular element end wall of the second tubular element may be provided with a hydrophobic coating. The first cavity of the first tubular element may be provided with a hydrophobic coating. The second cavity of the second tubular element may be provided with 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, traditionally measured through a liquid, where the liquid / vapor interface meets the solid surface. It quantifies the wettability of a solid surface by a 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 / m 2 , less than about 35 g / m 2 , less than about 30 g / m 2 , or less than about 25 g / m 2 .

[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 using the TAPPI T558 om-97 test, with results presented as interfacial contact angles, reported in degrees, which can range from approximately 0 degrees to approximately 180 degrees. If no contact angle is specified with the term hydrophobic, the water contact angle is at least 90 degrees.

[0091] One or both of the first and second tubular elements may be formed from a paper material, such as paper, paperboard, or cardboard. One or both of the first and second tubular elements may be formed from multiple overlapping paper layers, such as multiple parallel wound paper layers or multiple spirally wound paper layers. Forming one or both of the first and second tubular elements from multiple overlapping paper layers may help improve the tubular elements' resistance to collapse or deformation.

[0092] When one or both of the first and second tubular elements are formed from a paper material, the paper material may have a basis weight of at least about 90 grams per square meter. The paper material may have a basis weight of less than about 300 grams per square meter. The paper material may have a basis weight of about 100 to 200 grams per square meter. Advantageously, providing one or both of the first and second tubular elements with such a wall basis weight may help improve the resistance of the tubular elements to collapse or deformation.

[0093] The first tubular element can be formed from a first material. The second tubular element can be formed from a second material. The basis weight of the first material can be greater than the basis weight of the second material. The basis weight of the first material can be less than the basis weight of the second material. The first and second materials can be the same material, e.g., cardboard, but can have different basis weights. The first material can be any of the materials described above. The second material can be any of the materials described above.

[0094] The first tubular element may have a tubular wall thickness of at least about 0.1 millimeter, more preferably at least about 0.2 millimeter. Preferably, the first tubular element has a tubular wall thickness of less than about 1.5 millimeters, preferably less than about 1.25 millimeters. In preferred embodiments, the first tubular element has a tubular wall thickness of less than about 1 millimeter. The first tubular element, therefore, preferably has a tubular wall thickness of about 0.1 millimeter to about 1.5 millimeters, or about 0.2 millimeter to about 1.25 millimeters, or about 0.5 millimeter to about 1 millimeter. In some embodiments, the first tubular element may have a tubular wall thickness of about 0.15 millimeter to about 0.6 millimeters. Advantageously, providing a first tubular element with such a tubular wall thickness may help improve the first tubular element's resistance to collapse or deformation.

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

[0096] The second tubular element may have a tubular wall thickness of at least about 0.1 millimeter, more preferably at least about 0.2 millimeter. The second tubular element may have a tubular wall thickness of less than about 1.5 millimeters, preferably less than about 1.25 millimeters. In preferred embodiments, the second tubular element has a tubular wall thickness of less than about 1 millimeter. The second tubular element, therefore, preferably has a tubular wall thickness of about 0.1 millimeter to about 1.5 millimeters, or about 0.2 millimeter to about 1.25 millimeters, or about 0.5 millimeter to about 1 millimeter. In some embodiments, the second tubular element may have a tubular wall thickness of about 0.15 millimeter to about 0.6 millimeter. Advantageously, providing a second tubular element with such a tubular wall thickness may help improve the second tubular element's resistance to collapse or deformation.

[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 surrounding at least 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 surround at least the aerosol-forming substrate, the first tubular element, and the second tubular element. The outer wrapper may surround all of the multiple elements of the aerosol-generating article that are assembled in the form of a rod.

[0099] The outer wrapper may be 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 plug wrap. Suitable non-paper wrappers for use in certain 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 laminate material comprising multiple layers. Preferably, the wrapper is formed from an aluminum co-laminate sheet. The use of an aluminum-containing co-laminate sheet advantageously prevents the outer wrapper from burning if the aerosol-forming substrate is to be ignited rather than heated in the intended manner.

[0100] The aerosol-generating article includes a ventilation zone, which can advantageously increase cooling of the air and volatile compounds within one or both of the upstream and second tubular elements by drawing in cooler external air. It can also increase turbulence within the tubular elements, particularly if the ventilation zone draws air into the tubular elements in a direction transverse to the longitudinal axis of the tubular elements.

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

[0102] As described above, in embodiments, the first and second tubular elements may be longitudinally spaced apart. The ventilation zone may be located downstream of the first tubular element and upstream of the second tubular element. The ventilation zone may be located between the downstream end of the first tubular element and the upstream end of the second tubular element. The ventilation zone may be located between the first and second tubular elements.

[0103] The ventilation zone can be located at a position along the first tubular element. The ventilation zone can be located at a position along the second tubular element. For example, the ventilation zone can be located longitudinally between the upstream and downstream ends of the first or second tubular element. The characteristics of the ventilation zone are described below with respect to the aerosol-generating article. However, it will be understood that they can also be applied directly to the tubular elements themselves.

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

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

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

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

[0108] The ventilation zone may be located less than 10 millimeters from the upstream end wall of the first tubular element or the upstream 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 upstream end wall of the second tubular element, and 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 upstream end wall of the second tubular element.

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

[0110] Aerosol-generating articles according to the present invention may have a breathability level of at least about 5 percent.

[0111] The term "ventilation level" is used throughout this specification to mean the volume ratio of the airflow entering the aerosol-generating article via the ventilation zone (ventilation airflow) to the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the greater the dilution of the aerosol stream delivered to the consumer.

[0112] Aerosol-generating articles typically have a breathability level of at least about 10 percent, preferably at least about 15 percent, and more preferably at least about 20 percent.

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

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

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

[0116] Embodiments in which a ventilation zone is provided at a location along the first or second tubular element may provide a number of advantages. For example, without wishing to be bound by theory, the inventors have found that the temperature reduction caused by admitting cooler ambient air into the tubular element through the ventilation zone can have a beneficial effect on aerosol particle nucleation and growth.

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

[0118] As used herein, the term "susceptor element" refers to a material capable of converting electromagnetic energy into heat. When located within a varying electromagnetic field, induced eddy currents in the susceptor element cause the susceptor element to heat. When the elongated susceptor element is positioned in thermal contact with the aerosol-forming substrate, the aerosol-forming substrate is heated by the susceptor element.

[0119] The term "elongated" when used to describe a susceptor element means that the susceptor element has a length dimension that is greater than its width dimension or its thickness dimension, for example, more than twice its width dimension or its thickness dimension.

[0120] The susceptor elements may be disposed substantially longitudinally within the aerosol-forming substrate. This means that the length dimension of the elongated susceptor elements is disposed approximately parallel to the longitudinal axis of the aerosol-forming substrate, for example, within ±10 degrees of parallel to the longitudinal axis of the aerosol-forming substrate. In a preferred embodiment, the elongated susceptor elements may 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 susceptor element may extend from the upstream end of the aerosol-forming substrate to the downstream end of the aerosol-forming substrate. Preferably, the susceptor element extends all the way to the downstream end of the aerosol-forming substrate. The susceptor element may extend all the way to the upstream end of the aerosol-forming substrate. In a particularly preferred embodiment, the susceptor 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 susceptor elements are preferably in the form of pins, rods, strips or blades.

[0123] The susceptor element preferably has a length of about 5 millimeters to about 15 millimeters, such as, for example, about 6 millimeters to about 12 millimeters, or about 8 millimeters to about 10 millimeters.

[0124] The ratio of the length of the susceptor element to the overall length of the aerosol-generating article may be from about 0.2 to about 0.35.

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

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

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

[0128] The susceptor element preferably has a width of about 1 millimeter to about 5 millimeters.

[0129] The susceptor element may generally have a thickness of about 0.01 millimeters to about 2 millimeters, for example, about 0.5 millimeters to about 2 millimeters. The susceptor element may have a thickness of about 10 micrometers to about 500 micrometers, and more preferably about 10 micrometers to about 100 micrometers.

[0130] When the susceptor element has a constant cross-section, for example a circular cross-section, it has a preferred width or diameter of about 1 millimeter to about 5 millimeters.

[0131] When the susceptor elements have the form of strips or blades, the strips or blades preferably have a rectangular shape, preferably having a width of about 2 millimeters to about 8 millimeters, more preferably about 3 millimeters to about 5 millimeters. As an example, a susceptor element in the form of a blade strip may have a width of about 4 millimeters.

[0132] When the susceptor elements have the form of strips or blades, the strips or blades preferably have a rectangular shape and a thickness of about 0.03 millimeters to about 0.15 millimeters, more preferably about 0.05 millimeters to about 0.09 millimeters. As an example, a susceptor element in the form of a blade strip may have a thickness of about 0.07 millimeters.

[0133] In a preferred embodiment, the elongated susceptor elements are in the form of strips or blades, preferably having a rectangular shape and a thickness of about 55 micrometers to about 65 micrometers.

[0134] More preferably, the elongated susceptor elements have a thickness of about 57 micrometers to about 63 micrometers. Even more preferably, the elongated susceptor elements have a thickness of about 58 micrometers to about 62 micrometers. In a particularly preferred embodiment, the elongated susceptor elements have a thickness of about 60 micrometers.

[0135] The elongated susceptor elements preferably have a length that is the same as or shorter than the length of the aerosol-forming substrate. Preferably, the elongated susceptor elements have the same length as the aerosol-forming substrate.

[0136] The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. Preferred susceptor elements comprise metal or carbon.

[0137] Preferred susceptor elements may include or consist of a ferromagnetic material, such as a ferromagnetic alloy, ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptor elements may be or include aluminum. Preferred susceptor elements may be formed from 400 series stainless steel, such as grade 410, grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when placed in electromagnetic fields of similar frequency and field strength.

[0138] Thus, any of the susceptor element parameters, such as type of material, length, width, and thickness, can be varied to provide a desired power distribution within a known electromagnetic field. Preferred susceptor elements can be heated to temperatures in excess of 250 degrees Celsius.

[0139] Suitable susceptor elements may include a non-metallic core having a metal layer, such as a metal band formed on the surface of the ceramic core. The susceptor element may have a protective outer layer, such as a protective ceramic or glass layer, encapsulating the susceptor element. The susceptor element may include a protective coating formed of glass, ceramic, or an inert metal formed over a core of susceptor element material.

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

[0141] The heating of the aerosol-forming substrate and the temperature control of the heating can be separated by providing a susceptor element having at least first and second susceptor element materials with a second susceptor element material having a Curie temperature and a first susceptor element material without a Curie temperature, or by providing first and second susceptor element materials having different first and second Curie temperatures. The first susceptor element material is preferably a magnetic material having a Curie temperature greater than 500°C. From the standpoint of heating efficiency, it is desirable that the Curie temperature of the first susceptor element material exceed any maximum temperature to which the susceptor element can be heated. The second Curie temperature can be selected to be preferably lower than 400°C, preferably lower than 380°C, or lower than 360°C. The second susceptor element material is preferably a magnetic material selected to have a second Curie temperature substantially equal to the desired maximum heating temperature. That is, the second Curie temperature is preferably approximately the same as the temperature to which the susceptor element must be heated to generate an aerosol from the aerosol-forming substrate. The second Curie temperature may be, for example, within the range of 200° C. to 400° C., or within the range of 250° C. to 360° C. The second Curie temperature of the second susceptor element material may be selected, for example, so that the overall average temperature of the aerosol-forming substrate does not exceed 240° C. when heated by a susceptor element having a temperature equal to the second Curie temperature.

[0142] The aerosol-forming substrate may have a length of from about 10 millimeters to about 15 millimeters.The aerosol-forming substrate may have a length of from about 11 millimeters to about 12 millimeters.

[0143] The aerosol-forming substrate may comprise tobacco cut filler.

[0144] The aerosol-forming substrate may comprise a tobacco cast leaf.

[0145] The aerosol-forming substrate may be an assemblage of sheets of homogenized tobacco material. The assemblage of sheets of homogenized tobacco material may extend across substantially the entire transverse cross-sectional area of ​​the rod.

[0146] The homogenized tobacco material sheet assembly is 100 g / m 2 ~about 300g / m 2 The weight of the granules may be 100g.

[0147] The aggregate sheet of homogenized tobacco material may have a thickness of from 50 μm to about 300 μm.

[0148] The collected sheet of homogenized tobacco material may be a collected crimped sheet of homogenized tobacco material. The crimped sheet of homogenized tobacco material may have a plurality of ridges or corrugations substantially parallel to the longitudinal axis of the rod.

[0149] In certain 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 agglomeration of plant particles. For example, a sheet or web of homogenized tobacco material for the aerosol-forming substrate of the present invention may be formed by agglomerating particles of tobacco material obtained by grinding, crushing, or comminuting plant material and, optionally, one or more of tobacco lamina and tobacco stems. Homogenized plant material may be produced by casting, extrusion, a papermaking process, or any other suitable process known in the art.

[0151] The homogenized plant material may be provided in any suitable form. For example, the homogenized plant material may be in the form of one or more sheets. As used herein, the term "sheet" describes a thin layer of element having a width and length substantially greater than its thickness. The homogenized plant material may be in the form of a plurality of pellets or granules. The homogenized plant material may be in the form of a plurality of strands, pieces, or fragments. As used herein, the term "strand" describes an elongated element of material having a length substantially greater than its width and thickness. The term "strand" should be considered to encompass pieces, fragments, and any other homogenized plant material having a similar form. The strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or chopping, or by other methods, such as extrusion.

[0152] The strands may be formed in situ within the aerosol-forming substrate as a result of splitting or cracking of the sheet of homogenized plant material during the formation of the aerosol-forming substrate, for example, as a result of crimping. The strands of homogenized plant material within the aerosol-forming substrate may be separated from one another. At least some strands of homogenized plant material within the aerosol-forming substrate may be at least partially connected to adjacent strands or strands along their length. For example, adjacent strands may be connected by one or more fibers. This may occur, for example, when strands are formed due to splitting of the sheet of homogenized plant material during the manufacture of the aerosol-forming substrate, as described above.

[0153] The aerosol-forming substrate is preferably 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 paper-making process. The one or more sheets described herein can each individually have a thickness of 100 micrometers to 600 micrometers, preferably 150 micrometers to 300 micrometers, and most preferably 200 micrometers to 250 micrometers. Individual thickness refers to the thickness of an individual sheet, while combined thickness refers to the total thickness of all sheets comprising the aerosol-forming substrate. For example, if the aerosol-forming substrate is formed from two individual sheets, the combined thickness is the thickness of the two individual sheets or the sum of the measured thicknesses of the two sheets when the two sheets are stacked within the aerosol-forming substrate.

[0154] One or more of the sheets described herein may each individually have a weight of about 100 g / m 2 ~about 300g / m 2 The weight of the granules may be 100g.

[0155] One or more of the sheets described herein may each individually have a density of about 0.3 g / cm 3 ~Approx. 1.3g / cm 3 and may have a density of about 0.7 g / cm 3 ~Approx. 1.0g / cm 3 It is preferred that the density of the cellulose acylate is 0.05 to 0.15.

[0156] In embodiments in which the aerosol-forming substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of an assembly of one or more sheets. As used herein, the term "assembly" means that the sheets of homogenized plant material are coiled, folded, or otherwise compressed or contracted in a direction substantially transverse to the cylindrical axis of the plug or rod.

[0157] One or more sheets of homogenized plant material may be gathered transversely to their longitudinal axes and surrounded by a wrapper to form a continuous rod or plug.

[0158] One or more sheets of homogenized plant material may advantageously be crimped or similarly treated. As used herein, the term "crimped" means a sheet having a plurality of substantially parallel ridges or corrugations. Alternatively or additionally to being crimped, one or more sheets of homogenized plant material may be embossed, debossed, perforated, or otherwise deformed to provide texture to one or both sides of the sheet.

[0159] Preferably, each sheet of homogenized plant material can be crimped to have a plurality of ridges or corrugations substantially parallel to the longitudinal axis of the rod. This advantageously facilitates assembling the crimped sheets of homogenized plant material to form the aerosol-forming substrate. Preferably, one or more sheets of homogenized plant material can be assembled. Of course, the crimped sheets of homogenized plant material can alternatively or additionally have a plurality of substantially parallel ridges or corrugations that form acute or obtuse angles with respect to the longitudinal axis of the rod. The sheet can be crimped to an extent that the integrity of the sheet is interrupted at the plurality of parallel ridges or corrugations, causing separation of the material and resulting in the formation of pieces, strands, or strips of homogenized plant material.

[0160] One or more sheets of homogenized plant material can be cut into strands, as mentioned above. The aerosol-forming substrate can include multiple strands of homogenized plant material. The strands can be used to form plugs. Typically, the width of such strands is about 5 millimeters, about 4 millimeters, about 3 millimeters, or about 2 millimeters or less. The length of the strands can be greater than about 5 millimeters, about 5 millimeters to about 15 millimeters, about 8 millimeters to about 12 millimeters, or about 12 millimeters. 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 rod is cut into shorter plugs, and the length of the strands corresponds to the length of the plugs. Strands are fragile and may break, especially during transport. In such cases, the length of some of the strands may be shorter than the length of the plugs.

[0161] The strands preferably extend substantially longitudinally along the length of the aerosol-forming substrate, aligned with the longitudinal axis, and are therefore preferably aligned substantially parallel to one another.

[0162] The homogenized plant material may contain up to about 95 weight percent plant particles on a dry weight basis, preferably up to about 90 weight percent plant particles, more preferably up to about 80 weight percent plant particles, more preferably up to about 70 weight percent plant particles, more preferably up to about 60 weight percent plant particles, and even more preferably up to about 50 weight percent plant particles on a dry weight basis.

[0163] For example, the homogenized plant material can contain, on a dry weight basis, from about 2.5 weight percent to about 95 weight percent plant particles, or from about 5 weight percent to about 90 weight percent plant particles, or from about 10 weight percent to about 80 weight percent plant particles, or from about 15 weight percent to about 70 weight percent plant particles, or from about 20 weight percent to about 60 weight percent plant particles, or from about 30 weight percent to about 50 weight percent plant particles.

[0164] The homogenized plant material may be a homogenized tobacco material comprising tobacco particles. The sheets of homogenized tobacco material used in such embodiments may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at least about 50 weight percent on a dry weight basis, even more preferably at least about 70 weight percent on a dry weight basis, and most preferably at least about 90 weight percent on a dry weight basis.

[0165] The term "tobacco particles" refers to particles of any plant member of the genus Nicotiana. The term "tobacco particles" encompasses ground or powdered tobacco lamina, ground or powdered tobacco stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during tobacco processing, handling, and shipping. In preferred embodiments, the tobacco particles are derived substantially entirely from tobacco lamina. In contrast, isolated nicotine and nicotine salts, although tobacco-derived compounds, are not considered tobacco particles for purposes of the present invention and are not included in the proportion of particulate plant material.

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

[0167] Flame-curing is a tobacco curing method used specifically with Virginia tobacco. During the flue-curing process, heated air is circulated through tightly packed tobacco. During the first stage, the tobacco leaves yellow and wither. During the second stage, the leaf lamina dries completely. During the third stage, the leaf stem dries completely.

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

[0169] Orient is a type of tobacco with small leaves and high aromatic qualities. However, Orient tobacco has a milder flavor than, for example, Burley. Therefore, Orient tobacco is generally used in relatively small proportions in tobacco blends.

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

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

[0172] The homogenized plant material may include tobacco particles combined with non-tobacco plant flavor particles. Preferably, the non-tobacco plant flavor particles are selected from one or more of ginger, rosemary, eucalyptus, clove, and star anise particles. Preferably, in such embodiments, the homogenized plant material comprises, on a dry weight basis, at least about 2.5 weight percent of non-tobacco plant flavor particles, with the remaining plant particles being tobacco particles. Preferably, the homogenized plant material comprises, on a dry weight basis, at least about 4 weight percent of non-tobacco plant flavor particles, more preferably at least about 6 weight percent of non-tobacco plant flavor particles, more preferably at least about 8 weight percent of non-tobacco plant flavor particles, and more preferably at least about 10 weight percent of non-tobacco plant flavor particles. Preferably, the homogenized plant material comprises, on a dry weight basis, at most about 20 weight percent of non-tobacco plant flavor particles, more preferably at most about 18 weight percent of non-tobacco plant flavor particles, and more preferably at most about 16 weight percent of non-tobacco plant flavor particles.

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

[0174] The homogenized plant material may include cannabis particles. The term "cannabis particles" refers to particles of the cannabis plant, such as Cannabis sativa, Cannabis indica, and Cannabis ruderalis.

[0175] The homogenized plant material preferably comprises no more than 95 weight percent particulate plant material on a dry weight basis. Accordingly, the particulate plant material is typically combined with one or more other ingredients to form the homogenized plant material.

[0176] The homogenized plant material may further comprise a binder for modifying the mechanical properties of the particulate plant material, wherein the binder is included in the homogenized plant material during production as described herein. Suitable exogenous binders known to those skilled in the art are known 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, sodium alginate, agar, and conjugate base salts of organic acids such as pectin, and combinations thereof. Preferably, the binder comprises guar gum.

[0177] The binder may be present in an amount of about 1 weight percent to about 10 weight percent based on the dry weight of the homogenized plant material, preferably in an amount of about 2 weight percent to about 5 weight percent based on the dry weight of the homogenized plant material.

[0178] The homogenized plant material may further include one or more lipids to enhance the diffusion rate of the volatile components (e.g., aerosol formers, gingerol, and nicotine), where the lipids are included in the homogenized plant material during the processes described herein. Suitable lipids for inclusion 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.

[0179] The homogenized plant material may further include a pH modifier.

[0180] The homogenized plant material may further include fibers to alter the mechanical properties of the homogenized plant material, where the fibers are included in the homogenized plant material during the manufacturing process 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, soft wood fibers, hard wood 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" defined above. Before being included in the homogenized plant material, the fibers may be processed by a suitable process known in the art, including, but not limited to, mechanical pulping, refining, chemical pulping, bleaching, sulfate pulping, and combinations thereof. Typically, the fibers have a length greater than their width.

[0181] Suitable fibers are typically greater than 400 micrometers and have a length of 4 millimeters or less, with lengths in the range of 0.7 millimeters to 4 millimeters being preferred. The fibers are preferably present in an amount of about 2 weight percent to about 15 weight percent, most preferably about 4 weight percent, based on the dry weight of the substrate.

[0182] The aerosol-forming substrate, particularly the homogenized plant material, may further comprise one or more aerosol formers. Upon volatilization, the aerosol formers may carry other vaporized compounds, such as nicotine and flavorings in the aerosol, that are released from the aerosol-forming substrate upon heating. Suitable aerosol formers for inclusion in the homogenized plant material are known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, propylene glycol, 1,3-butanediol, and glycerol), esters of polyhydric alcohols (such as glycerol mono-, di-, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate and tetradecanedioate).

[0183] The aerosol-forming substrate, particularly homogenized plant material, may have an aerosol former content of from about 5 weight percent to about 30 weight percent on a dry weight basis, such as from about 10 weight percent to about 25 weight percent on a dry weight basis, or from about 15 weight percent to about 20 weight percent on a dry weight basis.

[0184] For example, when the substrate is intended for use in an aerosol-generating article for an electrically-operated aerosol-generating system having a heating element, the aerosol former content may preferably be about 5 weight percent to about 30 weight percent on a dry weight basis.When the substrate is intended for use in an aerosol-generating article for an electrically-operated aerosol-generating system having a heating element, the aerosol former is preferably glycerol.

[0185] The aerosol-forming substrate, particularly the homogenized plant material, may have an aerosol former content of about 1 percent to about 5 percent by weight on a dry weight basis. For example, if the substrate is intended for use in an aerosol-generating article in which the aerosol former is held in a reservoir separate from the substrate, the substrate may have an aerosol former content greater than 1 percent and less than about 5 percent. In such embodiments, the aerosol former volatilizes upon heating, and the aerosol former stream contacts the aerosol-forming substrate in a manner that incorporates flavors from the aerosol-forming substrate into the aerosol.

[0186] The aerosol-forming substrate, particularly the homogenized plant material, can have an aerosol-former content of about 30 to about 45 percent by weight. This relatively high level of aerosol former 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, on a dry weight basis, about 2 to about 10 percent by weight of cellulose ether and about 5 to about 50 percent by weight of additional cellulose. The use of a combination of cellulose ether and additional cellulose has been found to provide particularly effective aerosol delivery when used in an aerosol-forming substrate having an aerosol-former content of 30 to 45 percent by weight.

[0187] Suitable cellulose ethers include, but are not limited to, methyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, hydroxyl ethyl cellulose, hydroxyl propyl cellulose, ethyl hydroxyl ethyl cellulose and carboxymethyl cellulose (CMC). In a particularly preferred embodiment, the cellulose ether is carboxymethyl cellulose.

[0188] As used herein, the term "additional cellulose" encompasses any cellulose material incorporated into the homogenized plant material that is not derived from the non-tobacco plant particles or tobacco particles provided in the homogenized plant material. Thus, the additional cellulose is incorporated into the homogenized plant material as a separate and distinct cellulose source in addition to the non-tobacco plant material or tobacco material, relative to any cellulose inherently provided within the non-tobacco plant particles or tobacco particles. The additional cellulose is typically derived 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 sensorily inert and therefore does not substantially affect the sensory properties of the aerosol generated from the aerosol-forming substrate. For example, the additional cellulose is preferably a tasteless and odorless material.

[0189] The additional cellulose may include cellulose powder, cellulose fiber, or a combination thereof.

[0190] The aerosol former may act as a wetting agent in the aerosol-forming substrate.

[0191] The wrapper surrounding the rod of homogenized plant material can be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in certain embodiments of the present invention are known in the art and include, but are not limited to, cigarette paper and filter plug wrap. Suitable non-paper wrappers for use in certain 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 can be formed from a laminate material comprising multiple layers. Preferably, the wrapper is formed from an aluminum co-laminate sheet. The use of an aluminum-containing co-laminate sheet advantageously prevents combustion of the aerosol-forming substrate if the aerosol-forming substrate is to be ignited rather than heated in the intended manner.

[0192] In some preferred embodiments, the aerosol-forming substrate comprises a gel composition comprising an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound, hi particularly preferred embodiments, the aerosol-forming substrate comprises a gel composition comprising nicotine.

[0193] Preferably, the gel composition comprises an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound, an aerosol former, and at least one gelling agent. Preferably, the at least one gelling agent forms a solid medium, the glycerol is dispersed in the solid medium, and the alkaloid or cannabinoid is dispersed in the glycerol. Preferably, the gel composition is in a stable gel phase.

[0194] Advantageously, the stable gel composition comprising nicotine provides a predictable composition shape during storage or during transition from manufacture to consumer. The stable gel composition comprising nicotine substantially maintains its shape. The stable gel composition comprising nicotine does not substantially release a liquid phase during storage or during transition from manufacture to consumer. The stable gel composition comprising nicotine may provide a simple consumable design. The consumable may not need to be designed to contain a liquid, and therefore a wider range of materials and container structures may be contemplated.

[0195] The gel compositions described herein can be combined with an aerosol generating device to provide nicotine aerosol to the lungs at inhalation or airflow rates within those of traditional smoking. The aerosol generating device can continuously heat the gel composition. The consumer can take multiple inhalations or "puffs," with each "puff" delivering a quantity of nicotine aerosol. When heated, the gel composition can deliver a high-nicotine / low total particulate matter (TPM) aerosol to the consumer, preferably in a continuous manner.

[0196] The phrase "stable gel phase" or "stable gel" refers to a gel that substantially maintains its shape and mass when exposed to various environmental conditions. A stable gel cannot substantially release or absorb water (sweat) when exposed to standard temperatures and pressures while varying relative humidity from about 10 percent to about 60 percent. For example, a stable gel can substantially maintain its shape and mass when exposed to standard temperatures and pressures while varying relative humidity from about 10 percent to about 60 percent.

[0197] The gel composition may contain an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound. The gel composition may contain one or more alkaloids. The gel composition may contain one or more cannabinoids. The gel composition may contain a combination of one or more alkaloids and one or more cannabinoids.

[0198] The term "alkaloid compound" refers to any class of naturally occurring organic compounds containing one or more basic nitrogen atoms. Generally, alkaloids contain at least one nitrogen atom in an amine-type structure. This or another nitrogen atom within the molecule of an alkaloid compound can be active as a base in an acid-base reaction. Most alkaloid compounds have one or more of their nitrogen atoms as part of a ring system, such as a heterocycle. In nature, alkaloid compounds are found primarily in plants and are particularly common in certain families of flowering plants. However, some alkaloid compounds are found in animal species and fungi. In this disclosure, the term "alkaloid compound" refers to both naturally occurring and synthetically produced alkaloid compounds.

[0199] The gel composition preferably comprises an alkaloid compound selected from the group consisting of nicotine, anatabine, and combinations thereof.

[0200] Preferably, the gel composition comprises nicotine.

[0201] The term "nicotine" refers to nicotine and nicotine derivatives (eg, free base nicotine, nicotine salts, and the like).

[0202] The term "cannabinoid compounds" refers to any one of a class of naturally occurring compounds found in parts of the cannabis plant, including Cannabis sativa, Cannabis indica, and Cannabis ruderalis. Cannabinoid compounds are particularly concentrated in the female flower heads. Cannabinoid compounds that occur naturally in cannabis plants include cannabidiol (CBD) and tetrahydrocannabinol (THC). In this disclosure, the term "cannabinoid compounds" is used to describe both naturally occurring and synthetically produced cannabinoid compounds.

[0203] The gel may comprise a cannabinoid compound selected from the group consisting of cannabidiol (CBD), tetrahydrocannabinol (THC), tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), cannabicyclol (CBL), cannabivarin (CBV), tetrahydrocannabivarin (THCV), cannabidivarin (CBDV), cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabigerol monomethyl ether (CBGM), cannabielsoin (CBE), cannabicitran (CBT), and combinations thereof.

[0204] The gel composition may preferably comprise a cannabinoid compound selected from the group consisting of cannabidiol (CBD), THC (tetrahydrocannabinol) and combinations thereof.

[0205] The gel may preferably contain cannabidiol (CBD).

[0206] The gel composition may include nicotine and cannabidiol (CBD).

[0207] The gel composition may include nicotine, cannabidiol (CBD), and THC (tetrahydrocannabinol).

[0208] The gel composition preferably contains about 0.5 to about 10 weight percent alkaloid compounds, or about 0.5 to about 10 weight percent cannabinoid compounds, or a total of about 0.5 to about 10 weight percent alkaloid and cannabinoid compounds. The gel composition may contain about 0.5 to about 5 weight percent alkaloid compounds, or about 0.5 to about 5 weight percent cannabinoid compounds, or a total of about 0.5 to about 5 weight percent alkaloid and cannabinoid compounds. The gel composition preferably contains about 1 to about 3 weight percent alkaloid compounds, or about 1 to about 3 weight percent cannabinoid compounds, or a total of about 1 to about 3 weight percent alkaloid and cannabinoid compounds. The gel composition may preferably contain about 1.5 weight percent to about 2.5 weight percent alkaloid compounds, or about 1.5 weight percent to about 2.5 weight percent cannabinoid compounds, or a total amount of about 1.5 weight percent to about 2.5 weight percent alkaloid compounds and cannabinoid compounds. The gel composition may preferably contain about 2 weight percent alkaloid compounds, or about 2 weight percent cannabinoid compounds, or a total amount of about 2 weight percent alkaloid compounds and cannabinoid compounds. The alkaloid compound component of the gel formulation may be the most volatile component of the gel formulation. In some embodiments, water may be the most volatile component of the gel formulation, and the alkaloid compound component of the gel formulation may be the second most volatile component of the gel formulation. The cannabinoid compound component of the gel formulation may be the most volatile component of the gel formulation. In some embodiments, water may be the most volatile component of the gel formulation, and the alkaloid compound component of the gel formulation may be the second most volatile component of the gel formulation.

[0209] Preferably, nicotine is included in the gel composition. Nicotine can be added to the composition in free base or salt form. The gel composition contains about 0.5 weight percent to about 10 weight percent nicotine, or about 0.5 weight percent to about 5 weight percent nicotine. Preferably, the gel composition contains about 1 weight percent to about 3 weight percent nicotine, or about 1.5 weight percent to about 2.5 weight percent nicotine, or about 2 weight percent nicotine. The nicotine component of the gel formulation can be the most volatile component of the gel formulation. In some embodiments, water can be the most volatile component of the gel formulation, and the nicotine component of the gel formulation can be the second most volatile component of the gel formulation.

[0210] The gel composition preferably includes an aerosol former. Ideally, the aerosol former is substantially resistant to thermal degradation at the operating temperature of the associated aerosol-generating device. Suitable aerosol formers include, but are not limited to, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (such as dimethyl dodecanedioate and dimethyl tetradecanedioate). The polyhydric alcohol or mixture thereof may be one or more of triethylene glycol, 1,3-butanediol, and glycerin (glycerol or propane-1,2,3-triol) or polyethylene glycol. The aerosol former is preferably glycerol.

[0211] The gel composition comprises a majority of the aerosol former. The gel composition may comprise a mixture of water and aerosol former, with the aerosol former forming a majority (by weight) of the gel composition. The aerosol former may form at least about 50 weight percent of the gel composition. The aerosol former may form at least about 60 weight percent, or at least about 65 weight percent, or at least about 70 weight percent of the gel composition. The aerosol former may form about 70 weight percent to about 80 weight percent of the gel composition. The aerosol former may form about 70 weight percent to about 75 weight percent of the gel composition.

[0212] The gel composition may comprise a majority of glycerol. The gel composition may comprise a mixture of water and glycerol, with glycerol forming the majority (by weight) of the gel composition. Glycerol may form at least about 50 weight percent of the gel composition. Glycerol may form at least about 60 weight percent, or at least about 65 weight percent, or at least about 70 weight percent of the gel composition. Glycerol may form about 70 weight percent to about 80 weight percent of the gel composition. Glycerol may form about 70 weight percent to about 75 weight percent of the gel composition.

[0213] The gel composition preferably includes at least one gelling agent. The gel composition preferably includes a total amount of gelling agents ranging from about 0.4 weight percent to about 10 weight percent. More preferably, the composition includes gelling agents in a range of about 0.5 weight percent to about 8 weight percent. More preferably, the composition includes gelling agents in a range of about 1 weight percent to about 6 weight percent. More preferably, the composition includes gelling agents in a range of about 2 weight percent to about 4 weight percent. More preferably, the composition includes gelling agents in a range of about 2 weight percent to about 3 weight percent.

[0214] The term "gelling agent" refers to a compound that, when homogeneously added in an amount of about 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture, forms a solid medium or support matrix leading to a gel. Gelling agents include, but are not limited to, hydrogen-bond cross-linking gelling agents and ionic cross-linking gelling agents.

[0215] The gelling agent may comprise one or more biopolymers, which may be formed from polysaccharides.

[0216] Examples of biopolymers include gellan gum (natural gellan gum, low acyl gellan gum, high acyl gellan gum, and low acyl gellan gum are preferred), xanthan gum, alginate (alginic acid), agar, and guar gum. It may be preferable for the composition to include xanthan gum. The composition may include two biopolymers. The composition may include three biopolymers. The composition may include two biopolymers in substantially equal amounts by weight. The composition may include three biopolymers in substantially equal amounts by weight.

[0217] Preferably, the gel composition contains at least about 0.2 weight percent of a hydrogen-bond cross-linked gelling agent. The gel composition preferably contains at least about 0.2 weight percent of an ionic cross-linked gelling agent. Most preferably, the gel composition contains at least about 0.2 weight percent of a hydrogen-bond cross-linked gelling agent and at least about 0.2 weight percent of an ionic cross-linked gelling agent. The gel composition may contain from about 0.5 weight percent to about 3 weight percent of a hydrogen-bond cross-linked gelling agent and from about 0.5 weight percent to about 3 weight percent of an ionic cross-linked gelling agent, or from about 1 weight percent to about 2 weight percent of a hydrogen-bond cross-linked gelling agent and from about 1 weight percent to about 2 weight percent of an ionic cross-linked gelling agent. The hydrogen-bond cross-linked gelling agent and the ionic cross-linked gelling agent may be present in substantially equal amounts in the gel composition.

[0218] The term "hydrogen-bond cross-linking gelator" refers to a gelator that forms non-covalent or physical cross-links via hydrogen bonds. Hydrogen bonds are not covalent bonds to hydrogen atoms, but rather a type of electrostatic dipole-dipole attraction between molecules. They result from the attraction between a hydrogen atom covalently bonded to another extremely electronegative atom, such as an N, O, or F atom, and another extremely electronegative atom.

[0219] The hydrogen-bond cross-linking gelling agent may comprise one or more of galactomannan, gelatin, agarose, or konjac gum, or agar. Preferably, the hydrogen-bond cross-linking gelling agent comprises agar.

[0220] The gel composition preferably contains from about 0.3 weight percent to about 5 weight percent of the hydrogen-bond cross-linking gelling agent. Preferably, the composition contains from about 0.5 weight percent to about 3 weight percent of the hydrogen-bond cross-linking gelling agent. Preferably, the composition contains from about 1 weight percent to about 2 weight percent of the hydrogen-bond cross-linking gelling agent.

[0221] The gel composition may contain galactomannan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the galactomannan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the galactomannan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the galactomannan may be in the range of about 1 weight percent to about 2 weight percent.

[0222] The gel composition may contain gelatin in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the gelatin may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the gelatin may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the gelatin may be in the range of about 1 weight percent to about 2 weight percent.

[0223] The gel composition may contain agarose in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the agarose may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the agarose may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the agarose may be in the range of about 1 weight percent to about 2 weight percent.

[0224] The gel composition may contain konjac gum in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the konjac gum may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the konjac gum may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the konjac gum may be in the range of about 1 weight percent to about 2 weight percent.

[0225] The gel composition may contain agar in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the agar may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the agar may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the agar may be in the range of about 1 weight percent to about 2 weight percent.

[0226] The term "ionically cross-linking gelator" refers to a gelator that forms non-covalent 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 multivalent molecules with opposite charges are electrostatically attracted to each other, resulting in a cross-linked polymer network.

[0227] The ionic cross-linking gelling agent may include low acyl gellan, pectin, kappa carrageenan, iota carrageenan or alginate. Preferably, the ionic cross-linking gelling agent may include low acyl gellan.

[0228] The gel composition may comprise an ionically cross-linked gelling agent in the range of about 0.3 weight percent to about 5 weight percent. Preferably, the composition comprises an ionically cross-linked gelling agent in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the composition comprises an ionically cross-linked gelling agent in the range of about 1 weight percent to about 2 weight percent.

[0229] The gel composition may contain low acyl gellan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the low acyl gellan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the low acyl gellan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the low acyl gellan may be in the range of about 1 weight percent to about 2 weight percent.

[0230] The gel composition may comprise pectin in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the pectin may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the pectin may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the pectin may be in the range of about 1 weight percent to about 2 weight percent.

[0231] The gel composition may comprise kappa carrageenan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the kappa carrageenan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the kappa carrageenan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the kappa carrageenan may be in the range of about 1 weight percent to about 2 weight percent.

[0232] The gel composition may comprise iota carrageenan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the iota carrageenan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the iota carrageenan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the iota carrageenan may be in the range of about 1 weight percent to about 2 weight percent.

[0233] The gel composition may comprise alginate in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the alginate may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the alginate may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the alginate may be in the range of about 1 weight percent to about 2 weight percent.

[0234] The gel composition may contain a hydrogen-bond cross-linking gelator and an ionic cross-linking gelator in a ratio of about 3:1 to about 1:3. Preferably, the gel composition may contain a hydrogen-bond cross-linking gelator and an ionic cross-linking gelator in a ratio of about 2:1 to about 1:2. Preferably, the gel composition may contain a hydrogen-bond cross-linking gelator and an ionic cross-linking gelator in a ratio of about 1:1.

[0235] The gel composition may further comprise a thickening agent. The thickening agent in combination with the hydrogen-bond cross-linking gelling agent and the ionic cross-linking gelling agent surprisingly appears to support a solid medium and maintain the gel composition even when the gel composition contains high levels of glycerol.

[0236] The term "thickener" refers to a compound that, when uniformly added in an amount of 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture at 25 degrees Celsius, increases the viscosity without resulting in the formation of a gel, and causes the mixture to remain fluid. Preferably, a thickener refers to a compound that, when uniformly added in an amount of 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture at 25 degrees Celsius, 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 resulting in the formation of a gel, and causes the mixture to remain fluid. Preferably, a thickener refers to a compound that, when homogeneously added in an amount of 0.3 weight percent to a 50 weight percent water / 50 weight percent glycerol mixture at 25 degrees Celsius, increases the viscosity at a shear rate of 0.1 s-1 by at least 2 times, at least 5 times, at least 10 times, or at least 100 times greater than before addition without resulting in the formation of a gel, and the mixture becomes or remains fluid.

[0237] The viscosity values ​​provided herein may be measured using a Brookfield RVT viscometer with a disc type RV#2 spindle rotating at 25 degrees Celsius at a speed of 6 revolutions per minute (rpm).

[0238] The gel composition preferably comprises a thickening agent in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the composition comprises a thickening agent in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the composition comprises a thickening agent in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the composition comprises a thickening agent in the range of about 1 weight percent to about 2 weight percent.

[0239] The thickening agent may comprise one or more of xanthan gum, carboxymethylcellulose, microcrystalline cellulose, methylcellulose, gum arabic, guar gum, lambda carrageenan, or starch. Preferably, the thickening agent may comprise xanthan gum.

[0240] The gel composition may contain xanthan gum in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the xanthan gum may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the xanthan gum may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the xanthan gum may be in the range of about 1 weight percent to about 2 weight percent.

[0241] The gel composition may contain carboxymethylcellulose in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the carboxymethylcellulose may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the carboxymethylcellulose may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the carboxymethylcellulose may be in the range of about 1 weight percent to about 2 weight percent.

[0242] The gel composition may contain microcrystalline cellulose in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the microcrystalline cellulose may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the microcrystalline cellulose may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the microcrystalline cellulose may be in the range of about 1 weight percent to about 2 weight percent.

[0243] The gel composition may contain methylcellulose in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the methylcellulose may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the methylcellulose may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the methylcellulose may be in the range of about 1 weight percent to about 2 weight percent.

[0244] The gel composition may include gum arabic in the range of about 0.2 weight percent to about 5 weight percent. Preferably, gum arabic may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, gum arabic may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, gum arabic may be in the range of about 1 weight percent to about 2 weight percent.

[0245] The gel composition may contain guar gum in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the guar gum may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the guar gum may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the guar gum may be in the range of about 1 weight percent to about 2 weight percent.

[0246] The gel composition may comprise lambda carrageenan in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the lambda carrageenan may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the lambda carrageenan may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the lambda carrageenan may be in the range of about 1 weight percent to about 2 weight percent.

[0247] The gel composition may comprise starch in the range of about 0.2 weight percent to about 5 weight percent. Preferably, the starch may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the starch may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the starch may be in the range of about 1 weight percent to about 2 weight percent.

[0248] The gel composition may further comprise a divalent cation. Preferably, the divalent cation comprises calcium ions, such as calcium lactate in solution. The divalent cation (e.g., calcium ions) may aid in gel formation in compositions that include a gelling agent, such as an ionically crosslinking gelling agent. Ionic effects may aid gel formation. The divalent cation may be present in the gel composition in a range of about 0.1 to about 1 weight percent, or about 0.5 weight percent.

[0249] The gel composition may further comprise an acid. The acid may comprise a carboxylic acid. The carboxylic acid may comprise a ketone group. Preferably, the carboxylic acid may comprise a ketone group having less than about 10 carbon atoms, such as levulinic acid or lactic acid, or less than about 6 carbon atoms, or less than about 4 carbon atoms. Preferably, the carboxylic acid has three carbon atoms (such as lactic acid). Lactic acid surprisingly improves the stability of the gel composition over similar carboxylic acids. The carboxylic acid may aid in gel formation. The carboxylic acid may reduce changes in the alkaloid compound concentration, or cannabinoid compound concentration, or both the alkaloid compound concentration and the cannabinoid compound concentration in the gel composition during storage. The carboxylic acid may reduce changes in the nicotine concentration in the gel composition during storage.

[0250] The gel composition may include a carboxylic acid in the range of about 0.1 weight percent to about 5 weight percent. Preferably, the carboxylic acid may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the carboxylic acid may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the carboxylic acid may be in the range of about 1 weight percent to about 2 weight percent.

[0251] The gel composition may contain lactic acid in the range of about 0.1 weight percent to about 5 weight percent. Preferably, the lactic acid may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the lactic acid may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the lactic acid may be in the range of about 1 weight percent to about 2 weight percent.

[0252] The gel composition may include levulinic acid in the range of about 0.1 weight percent to about 5 weight percent. Preferably, the levulinic acid may be in the range of about 0.5 weight percent to about 3 weight percent. Preferably, the levulinic acid may be in the range of about 0.5 weight percent to about 2 weight percent. Preferably, the levulinic acid may be in the range of about 1 weight percent to about 2 weight percent.

[0253] The gel composition preferably contains some water. When the composition contains some water, the gel composition is more stable. The gel composition preferably contains at least about 1 weight percent, or at least about 2 weight percent, or at least about 5 weight percent water. The gel composition preferably contains at least about 10 weight percent or at least about 15 weight percent water.

[0254] The gel composition preferably contains about 8 weight percent to about 32 weight percent water. The gel composition preferably contains about 15 weight percent to about 25 weight percent water. The gel composition preferably contains about 18 weight percent to about 22 weight percent water. The gel composition preferably contains about 20 weight percent water.

[0255] Preferably, the aerosol-forming substrate contains from about 150 mg to about 350 mg of the gel composition.

[0256] Preferably, in embodiments comprising a gel composition, the aerosol-forming substrate comprises a porous medium loaded with the gel composition. An advantage of a porous medium loaded with a gel composition is that the gel composition is retained within the porous medium, which may aid in the manufacture, storage, or transport of the gel composition. This may help maintain the desired shape of the gel composition, particularly during manufacture, transport, or use.

[0257] The term "porous" is used herein to refer to a material that provides a plurality of pores or openings that allow the passage of air through the material.

[0258] The porous medium can be any suitable porous material capable of holding or retaining the gel composition. Ideally, the porous medium can allow the gel composition to move within it. In certain embodiments, the porous medium comprises natural, synthetic, or semi-synthetic materials, or a combination thereof. In certain embodiments, the porous medium comprises a sheet material, a foam, or a fiber, e.g., loose fiber, or a combination thereof. In certain embodiments, the porous medium comprises a woven fabric, a nonwoven fabric, or an extruded material, or a combination thereof. Preferably, the porous medium comprises cotton, paper, viscose, PLA, or cellulose acetate, or a combination thereof. Preferably, the porous medium comprises a sheet material, e.g., cotton or cellulose acetate. In a particularly preferred embodiment, the porous medium comprises a sheet made from cotton fibers.

[0259] The porous medium may be crimped or chopped. In a preferred embodiment, the porous medium is crimped. In an alternative embodiment, the porous medium comprises chopped porous medium. The crimping or chopping process can be before or after loading with the gel composition.

[0260] Crimping the sheet material has the advantage of improving the structure and allowing passageways through the structure. The passageways through the crimped sheet material aid in gel loading, gel retention, and fluid passage through the crimped sheet material. Therefore, there are advantages to using crimped sheet materials as porous media.

[0261] The shredding provides the medium with a high surface area to volume ratio so that it can readily absorb the gel.

[0262] In certain embodiments, the sheet material is a composite material. Preferably, the sheet material is porous. The sheet material may aid in the manufacture of the tubular element containing the gel. The sheet material may aid in the introduction of an active agent into the tubular element containing the gel. The sheet material may help stabilize the structure of the tubular element containing the gel. The sheet material may aid in the transportation or storage of the gel. The use of the sheet material allows or aids in adding structure to the porous medium, for example, by crimping the sheet material.

[0263] The porous medium can be a thread. The thread can include, for example, cotton, paper, or acetate tow. The thread can also be loaded with a gel, like any other porous medium. An advantage of using a thread as the porous medium is that it can aid in ease of manufacturing.

[0264] The threads can be loaded with gel by any known means. They can be simply coated with gel, or they can be impregnated with gel. In manufacturing, the threads can be impregnated with gel and stored ready to use for inclusion in the assembly of tubular elements.

[0265] Preferably, in embodiments in which the first component comprises a gel composition, as described above, the tubular component has a length of less than 10 millimeters. The use of such a relatively short tubular component in combination with the gel composition may optimize delivery of the aerosol to the consumer.

[0266] The aerosol-generating article may include a capsule. The aerosol-forming substrate may be disposed within the capsule. During use, a consumer may burst the capsule and inhale the aerosol-generating article, which causes the capsule to move within the aerosol-generating article and releases the aerosol-forming substrate to form an aerosol that can be inhaled and delivered to the consumer's lungs. As used herein, the term "rupturing" refers to providing at least one opening within the capsule to allow the aerosol-forming substrate within the capsule to exit the capsule. For example, a consumer may insert a rupturing element through the distal end of the aerosol-generating article to rupture the capsule. As another example, the capsule may be ruptured by the consumer applying force to the capsule, such as with their fingers.

[0267] The capsule may comprise a capsule shell for enclosing the aerosol-forming substrate. The capsule may be any suitable pharmaceutical capsule, such as a hard-shell capsule. The capsule shell may be made from a gelling agent such as gelatin and / or a polysaccharide. The capsule shell may be formed from hydroxypropyl methylcellulose (HPMC). The capsule shell may contain a plasticizer such as glycerin or sorbitol.

[0268] As used herein, the term "pharmaceutically active ingredient" refers to an ingredient that alters one or more chemical or physiological functions of a cell, tissue, organ, or organism.

[0269] The aerosol-forming substrate disposed within the capsule may be a dry powder. The dry powder may include a pharmaceutically active ingredient. The pharmaceutically active ingredient may be nicotine.

[0270] 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 comprising an electrical element for heating an aerosol-forming substrate.

[0271] The aerosol generating device may include a power source. The power source may be configured to provide power to the electrical elements. The power source may be any suitable power source, for example, a direct current voltage source such as a battery. In one embodiment, the power source is a lithium-ion battery. Alternatively, the power source may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery (e.g., a lithium-cobalt battery, a lithium iron phosphate battery, a lithium titanate battery, or a lithium polymer battery).

[0272] The aerosol-generating device may include a cavity for receiving the aerosol-generating article.

[0273] The electrical element may be a heating element. The electrical element may be disposed within or around a cavity of the aerosol generating device. The electrical element may be an inductor, such as an induction coil.

[0274] The aerosol-generating device may comprise an internal heating element, for example a pin or blade that is at least partially inserted into the aerosol-forming substrate for use. The internal heating element may be configured to be inserted into a radially central position of the aerosol-forming substrate.

[0275] The aerosol generating device may include an external heating element positioned around the periphery of the cavity of the aerosol generating device. The external heating element may take any suitable form. For example, the external heating element may take the form of one or more flexible heating foils on a dielectric substrate such as polyimide. The flexible heating foils may be shaped to fit around the cavity. Alternatively, the external heating element may take the form of a metal grid, a flexible printed circuit board, a molded integrated circuit device (MID), a ceramic heating element, a flexible carbon fiber heating element, or may be formed using a coating technique such as plasma deposition onto a suitably shaped substrate.

[0276] It will be appreciated that any feature described with respect to one aspect of the invention or disclosure is equally applicable to any other aspect of the invention or disclosure. [Example]

[0277] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features described above, for example, with any one or more features of other examples, embodiments, or aspects described herein.

[0278] Example 1 1. An aerosol-generating article comprising a plurality of elements assembled in the form of a rod, the plurality of elements comprising: an aerosol-forming substrate; a first tubular element including an upstream end wall defining a first opening for permitting fluid communication between an interior of the first tubular element and an exterior of the first tubular element; a second tubular element including a second tubular element end wall defining a second opening for allowing fluid communication between an interior of the second tubular element and an exterior of the second tubular element; An aerosol-generating article, wherein a first tubular element is positioned within the rod upstream of and adjacent to a second tubular element. Example 2. 10. The aerosol-generating article of example 1, wherein the downstream end of the first tubular element is in physical contact with the upstream end of the second tubular element. Example 3. 3. The aerosol-generating article of any one of Examples 1 to 2, wherein the first tubular element and the second tubular element are positioned upstream of the aerosol-forming substrate. Example 4. An aerosol-generating article according to any one of Examples 1 to 3, wherein the first tubular element is the most upstream element of the aerosol-generating article. Example 5. An aerosol-generating article according to any one of Examples 1 to 4, wherein the first tubular element is located at the most upstream end of the aerosol-generating article. Example 6 6. An aerosol-generating article according to any one of Examples 1 to 5, wherein the second tubular element is positioned adjacent to the upstream end aerosol-forming substrate. Example 7 7. An aerosol-generating article according to any one of Examples 1 to 6, wherein the second tubular element is in physical contact with the upstream end of the aerosol-forming substrate. Example 8 8. The aerosol-generating article of example 7, wherein the second tubular element end wall is in physical contact with the upstream end of the aerosol-forming substrate. Example 9. 3. The aerosol-generating article of example 1 or 2, wherein the first tubular element and the second tubular element are positioned downstream of the aerosol-forming substrate. Example 10. 10. The aerosol-generating article of Example 9, wherein the second tubular element is the most downstream element of the aerosol-generating article. Example 11 11. An aerosol-generating article according to any one of Examples 9 and 10, wherein the second tubular element is positioned at the most downstream end of the aerosol-generating article. Example 12 12. The aerosol-generating article of any one of Examples 9 to 11, wherein the first tubular element is positioned adjacent to the downstream end of the aerosol-forming substrate. Example 13 13. The aerosol-generating article of any one of Examples 9 to 12, wherein the first tubular element is in physical contact with the downstream end of the aerosol-forming substrate. Example 14. 14. The aerosol-generating article of example 13, wherein the upstream end wall of the first tubular element is in physical contact with the downstream end of the aerosol-forming substrate. Example 15. An aerosol-generating article according to any one of Examples 9 to 14, wherein the element positioned downstream of the second tubular element has a withdrawal resistance of about 0 mmH2O. Example 16. An aerosol-generating article according to any one of Examples 9 to 15, wherein there is no filter element made of cellulose acetate positioned downstream of the second tubular element. Example 17. An aerosol-generating article according to any one of Examples 9 to 16, wherein there is no filter element positioned downstream of the second tubular element. Example 18. An aerosol-generating article according to any one of Examples 9 to 17, wherein the second tubular element end wall of the second tubular element is positioned less than 15 millimeters from the downstream end of the aerosol-generating article. Example 19. An aerosol-generating article according to any one of Examples 9 to 18, wherein the second tubular element end wall of the second tubular element is positioned less than 10 millimeters from the downstream end of the aerosol-generating article. Example 20. 20. An aerosol-generating article according to any one of Examples 9 to 19, wherein the second tubular element end wall of the second tubular element is positioned less than 5 millimeters from the downstream end of the aerosol-generating article. Example 21. 21. An aerosol-generating article according to any one of Examples 1 to 20, wherein the upstream end wall is formed by a first folded end portion, preferably the first folded end portion being a flange end portion. Example 22. An aerosol-generating article described in any one of Examples 1 to 121, wherein the second tubular element end wall is formed by a second folded end portion, preferably the second folded end portion is a flange end portion. Example 23. An aerosol-generating article according to any one of Examples 1 to 22, wherein the downstream end of the first tubular element does not have an end wall. Example 24. An aerosol-generating article according to any one of Examples 1 to 23, wherein the upstream end of the second tubular element is devoid of an end wall. Example 25. An aerosol-generating article according to any one of Examples 1 to 24, wherein the first tubular element comprises a first cavity extending from the upstream end wall of the first tubular element to the downstream end of the first tubular element. Example 26. The aerosol-generating article of Example 25, wherein the first cavity is empty. Example 27. 27. The aerosol-generating article of example 25 or 26, wherein the first cavity has a diameter that is at least about 50 percent of the diameter of the first tubular element. Example 28. 28. The aerosol-generating article of any one of Examples 25-27, wherein the first cavity has a diameter that is at least about 60 percent of the diameter of the first tubular element. Example 29. 29. The aerosol-generating article of any one of Examples 25-28, wherein the first cavity has a diameter that is at least about 70 percent of the diameter of the first tubular element. Example 30. 30. The aerosol-generating article of any one of Examples 25-29, wherein the first cavity has a diameter that is at least about 80 percent of the diameter of the first tubular element. Example 31. An aerosol-generating article according to any one of Examples 25 to 30, wherein the first cavity has a diameter that is at least about 90 percent of the diameter of the first tubular element. Example 32. An aerosol-generating article according to any one of Examples 25 to 31, wherein the first cavity has a diameter that is at least about 95 percent of the diameter of the first tubular element. Example 33. 33. The aerosol-generating article of any one of Examples 25 to 32, 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. Example 34. 33. The aerosol-generating article of any one of Examples 25 to 32, 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. Example 35. 33. The aerosol-generating article of any one of Examples 25 to 32, 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. Example 36. 33. The aerosol-generating article of any one of Examples 25 to 32, wherein the diameter of the first cavity decreases from the upstream end wall of the first tubular element to the downstream end of the first tubular element. Example 37. An aerosol-generating article according to any one of Examples 25 to 32, wherein the diameter of the first cavity is substantially constant between the upstream end wall of the first tubular element and the downstream end of the first tubular element. Example 38. 38. The aerosol-generating article of Example 37, wherein the diameter of the cavity is substantially constant from the upstream end wall of the first tubular element to the downstream end of the first tubular element. Example 39. An aerosol-generating article according to any one of Examples 1 to 38, wherein the second tubular element comprises a second cavity extending from the upstream end of the second tubular element to the downstream end of the second tubular element. Example 40. An aerosol-generating article according to any one of Examples 39, wherein the second cavity is empty. Example 41. 41. The aerosol-generating article of example 39 or 40, wherein the diameter of the second cavity is at least about 50 percent of the diameter of the second tubular element. Example 42. An aerosol-generating article according to any one of Examples 39 to 41, wherein the diameter of the second cavity is at least about 60 percent of the diameter of the second tubular element. Example 43. An aerosol-generating article according to any one of Examples 39 to 42, wherein the diameter of the second cavity is at least about 70 percent of the diameter of the second tubular element. Example 44. An aerosol-generating article described in any one of Examples 39 to 43, wherein the diameter of the second cavity is at least about 80 percent of the diameter of the second tubular element. Example 45. An aerosol-generating article according to any one of Examples 39 to 44, wherein the diameter of the second cavity is at least about 90 percent of the diameter of the second tubular element. Example 46. An aerosol-generating article described in any one of Examples 39 to 45, wherein the diameter of the second cavity is at least about 95 percent of the diameter of the second tubular element. Example 47. 47. The aerosol-generating article of any one of Examples 39 to 46, wherein the diameter of the second cavity increases between the upstream end of the second tubular element and the downstream end of the second tubular element. Example 48. 47. The aerosol-generating article of any one of Examples 39 to 46, wherein the diameter of the second cavity increases from the upstream end of the second tubular element to the downstream end of the second tubular element. Example 49. 47. The aerosol-generating article of any one of Examples 39 to 46, wherein the diameter of the second cavity decreases between the upstream end of the second tubular element and the downstream end of the second tubular element. Example 50. 47. The aerosol-generating article of any one of Examples 39 to 46, wherein the diameter of the second cavity decreases from the upstream end of the second tubular element to the downstream end of the second tubular element. Example 51. An aerosol-generating article described in any one of Examples 39 to 46, wherein the diameter of the second cavity is substantially constant between the upstream end of the second tubular element and the downstream end of the second tubular element. Example 52. 52. The aerosol-generating article of Example 51, wherein the diameter of the second cavity is substantially constant from the upstream end of the second tubular element to the downstream end of the second tubular element. Example 53. An aerosol-generating article according to any one of Examples 1 to 52, comprising a continuous cavity extending from the upstream end wall of the first tubular element to the downstream end of the second tubular element. Example 54. 54. The aerosol-generating article of Example 53, wherein the continuous cavity has a uniform diameter along the entire length of the continuous cavity. Example 55. An aerosol-generating article according to any one of Examples 1 to 54, wherein the first tubular element has a length greater than the length of the second tubular element. Example 56. An aerosol-generating article according to any one of Examples 1 to 54, wherein the first tubular element has a length that is shorter than the length of the second tubular element. Example 57. An aerosol-generating article according to any one of Examples 1 to 54, wherein the first tubular element has a length substantially equal to the length of the second tubular element. Example 58. An aerosol-generating article according to any one of Examples 1 to 57, wherein the first opening is radially aligned with the second opening. Example 59. The aerosol-generating article of any one of Examples 1 to 57, wherein the first opening is radially offset from the second opening. Example 60. An aerosol-generating article according to any one of Examples 1 to 59, wherein the first opening is radially central. Example 61. An aerosol-generating article according to any one of Examples 1 to 59, wherein the second opening is radially central. Example 62. 61. The aerosol-generating article of any one of Examples 1 to 60, wherein the first opening has an equivalent diameter that is greater than or equal to about 10 percent of the diameter of the upstream end wall. Example 63. 62. The aerosol-generating article of any one of Examples 1-61, wherein the first opening has an equivalent diameter that is greater than or equal to about 20 percent of the diameter of the upstream end wall. Example 64. 63. The aerosol-generating article of any one of Examples 1-62, wherein the first opening has an equivalent diameter that is greater than or equal to about 30 percent of the diameter of the upstream end wall. Example 65. An aerosol-generating article according to any one of Examples 1 to 63, wherein the first opening has an equivalent diameter of about 40 percent or more of the diameter of the upstream end wall. Example 66. 65. The aerosol-generating article of any one of Examples 1-64, wherein the first opening has an equivalent diameter that is greater than or equal to about 50 percent of the diameter of the upstream end wall. Example 67. 66. The aerosol-generating article of any one of Examples 1 to 65, wherein the first opening has an equivalent diameter of about 1 millimeter to about 3 millimeters. Example 68. 67. An aerosol-generating article according to any one of Examples 1 to 66, wherein the second opening has an equivalent diameter of at least about 10 percent of the diameter of the second tubular element end wall. Example 69. An aerosol-generating article according to any one of Examples 1 to 67, wherein the second opening has an equivalent diameter of about 20 percent or greater than the diameter of the second tubular element end wall. Example 70. An aerosol-generating article according to any one of Examples 1 to 68, wherein the second opening has an equivalent diameter of at least about 30 percent of the diameter of the second tubular element end wall. Example 71. 69. An aerosol-generating article according to any one of Examples 1 to 69, wherein the second opening has an equivalent diameter of at least about 40 percent of the diameter of the second tubular element end wall. Example 72. 71. An aerosol-generating article according to any one of Examples 1 to 70, wherein the second opening has an equivalent diameter of about 50 percent or more of the diameter of the second tubular element end wall. Example 73. 72. The aerosol-generating article of any one of Examples 1 to 71, wherein the second opening has an equivalent diameter of about 1 millimeter to about 3 millimeters. Example 74. 73. The aerosol-generating article of any one of Examples 1 to 72, wherein the first opening has an equivalent diameter that is smaller than the equivalent diameter of the second opening. Example 75. 73. The aerosol-generating article of any one of Examples 1 to 72, wherein the first opening has an equivalent diameter that is smaller than the equivalent diameter of the second opening. Example 76. 73. The aerosol-generating article of any one of Examples 1 to 72, wherein the first opening has an equivalent diameter substantially equal to the equivalent diameter of the second opening. Example 77. An aerosol-generating article described in any one of Examples 1 to 76, wherein the upstream end wall defines a plurality of openings to allow fluid communication between the interior of the first tubular element and the exterior of the first tubular element. Example 78. An aerosol-generating article described in any one of Examples 1 to 77, wherein the end wall of the second tubular element defines a plurality of openings to allow fluid communication between the interior of the second tubular element and the exterior of the second tubular element. Example 79. 79. The aerosol-generating article of any one of Examples 1 to 78, wherein the number of openings defined in the upstream end wall is greater than the number of openings defined in the second tubular element end wall. Example 80. An aerosol-generating article according to any one of Examples 1 to 79, further comprising a front plug located upstream of the aerosol-forming substrate. Example 81. 81. The aerosol-generating article of Example 80, wherein the front plug is the most upstream element of the aerosol-generating article. Example 82. 82. The aerosol-generating article of example 80 or 81, wherein the front plug is in physical contact with the upstream end of the aerosol-forming substrate. Example 83. 83. The aerosol-generating article of any one of Examples 80 to 82, wherein the front plug is a hollow element, for example, the front plug is in the form of a tube. Example 84. 84. The aerosol-generating article of any one of Examples 80 to 83, wherein the front plug is made from cellulose acetate, for example, the front plug is a hollow cellulose acetate tube. Example 85. 85. The aerosol-generating article of any one of Examples 80 to 84, wherein the front plug has a length of about 2 millimeters to about 8 millimeters. Example 86. The aerosol generation of any one of Examples 80-85, wherein the front plug has a length of about 5 millimeters. Example 87. 87. The aerosol-generating article of any one of Examples 1-86, wherein the upstream end wall of the first tubular element comprises a hydrophobic coating. Example 88. 88. The aerosol-generating article of any one of Examples 1-87, wherein the second tubular element end wall of the second tubular element comprises a hydrophobic coating. Example 89. The aerosol-generating article of any one of Examples 1-88, wherein the first tubular element comprises a hydrophobic coating. Example 90. 89. The aerosol-generating article of any one of Examples 1 to 89, wherein the second tubular element comprises a hydrophobic coating. Example 91. 91. The aerosol-generating article of any one of Examples 1 to 90, wherein one or both of the first tubular element and the second tubular element are formed from a paper material. Example 92. 92. The aerosol-generating article of any one of Examples 1-91, wherein one or both of the first tubular element and the second tubular element are formed from cardboard. Example 93. 93. An aerosol-generating article according to any one of Examples 1 to 92, wherein the tubular wall thickness of the first tubular element is greater than the tubular wall thickness of the second tubular element. Example 94. An aerosol-generating article according to any one of Examples 1 to 92, wherein the tubular wall thickness of the first tubular element is less than the tubular wall thickness of the second tubular element. Example 95. 95. The aerosol generation of any one of Examples 1-94, wherein the tubular wall thickness is from about 150 micrometers to about 600 micrometers. Example 96. An aerosol-generating article according to any one of Examples 1 to 95, comprising an outer wrapper surrounding at least a first tubular element and a second tubular element. Example 97. 97. The aerosol-generating article of Example 96, wherein the outer wrapper extends from the upstream end of the first tubular element to the downstream end of the second tubular element. Example 98. 98. An aerosol-generating article according to any one of Examples 96 to 97, wherein the outer wrapper surrounds all of the multiple elements of the aerosol-generating article that are assembled in the form of a rod. Example 99. The aerosol-generating article of any one of Examples 96-98, wherein the outer wrapper is a paper wrapper or a non-paper wrapper. Example 100. An aerosol-generating article according to any one of Examples 1 to 99, further comprising a ventilation zone located between the upstream end of the aerosol-generating article and the downstream end of the aerosol-generating article. Example 101. 101. The aerosol-generating article of example 100, wherein the ventilation zone is located downstream of the aerosol-forming substrate. Example 102. 102. The aerosol-generating article of example 100 or 101, wherein the ventilation zone is located at a position along the first tubular element. Example 103. 102. The aerosol-generating article of example 100 or 101, wherein the ventilation zone is located at a position along the second tubular element. Example 104. The aerosol-generating article of any one of Examples 100-103, wherein the ventilation zone has a ventilation level of about 30 percent to about 60 percent. Example 105. The aerosol-generating article of any one of Examples 1-104, further comprising a susceptor element positioned in thermal contact with the aerosol-forming substrate. Example 106. 106. The aerosol-generating article of example 105, wherein the susceptor element is positioned within the aerosol-forming substrate. Example 107. 107. The aerosol-generating article of any one of Examples 105 and 106, wherein the susceptor element is an elongated susceptor longitudinally disposed within the aerosol-forming substrate. Example 108. 108. The aerosol-generating article of any one of Examples 105-107, wherein the susceptor element extends along a radially central axis of the aerosol-forming substrate. Example 109. 109. The aerosol-generating article of any one of Examples 105 to 108, wherein the susceptor element extends from the upstream end of the aerosol-forming substrate to the downstream end of the aerosol-forming substrate. Example 110. The aerosol-generating article of any one of Examples 105-109, wherein the susceptor element is in the form of a pin, rod, or blade. Example 111. The aerosol-generating article of any one of Examples 1 to 110, wherein the aerosol-forming substrate comprises tobacco cut filler. Example 112. The aerosol-generating article of any one of Examples 1 to 111, wherein the aerosol-forming substrate comprises a tobacco cast leaf. Example 113. 113. An aerosol-generating article according to any one of Examples 1 to 112, wherein the aerosol-forming substrate is an assembly of sheets of homogenized tobacco material. Example 114. An aerosol-generating article as described in Example 113, wherein the aggregate of sheets of homogenized tobacco material extends across substantially the entire transverse cross-sectional area of ​​the rod. Example 115. 115. The aerosol-generating article of Example 113 or 114, wherein the assembly of sheets of homogenized tobacco material has a basis weight of from 100 g / m2 to about 300 g / m2. Example 116. 116. The aerosol-generating article of any one of Examples 113 to 115, wherein the assembly of sheets of homogenized tobacco material has a thickness of from 50 μm to about 300 μm. Example 117. 117. The aerosol-generating article of any one of Examples 113 to 116, wherein the collection of sheets of homogenized tobacco material is a collection of crimped sheets of homogenized tobacco material. Example 118. An aerosol-generating article as described in Example 117, wherein the assembly of crimped sheets of homogenized tobacco material has a plurality of ridges or corrugations substantially parallel to the longitudinal axis of the rod. Example 119. 119. The aerosol-generating article of any one of Examples 1 to 118, wherein the aerosol-forming substrate comprises one or more aerosol-forming bodies. Example 120. 120. The aerosol-generating article of example 119, wherein the aerosol-forming substrate has an aerosol former content of about 10 weight percent to about 50 weight percent on a dry weight basis. Example 121. 121. The aerosol-generating article of any one of Examples 1 to 120, wherein the aerosol-forming substrate has a length of from about 10 millimeters to about 15 millimeters. Example 122. 122. The aerosol-generating article of any one of Examples 1 to 121, wherein the aerosol-forming substrate has a length of from about 11 millimeters to about 12 millimeters.

[0279] The embodiments will now be further described with reference to the figures. [Brief explanation of the drawings]

[0280] [Figure 1] FIG. 1 shows a schematic cross-sectional view of an aerosol-generating article according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 shows a schematic cross-sectional view of an aerosol-generating article according to a second embodiment of the present disclosure. [Figure 3] FIG. 3 shows a schematic cross-sectional view of an aerosol-generating article according to a third embodiment of the present disclosure. [Figure 4] FIG. 4 shows a schematic cross-sectional view of an aerosol-generating article according to a fourth embodiment of the present disclosure. [Figure 5] FIG. 5 shows a schematic cross-sectional view of an aerosol-generating article according to a fifth embodiment of the present disclosure. [Figure 6] FIG. 6 shows a schematic cross-sectional view of an aerosol-generating article according to a sixth embodiment of the present disclosure. [Figure 7] FIG. 7 shows a schematic cross-sectional view of an aerosol-generating article according to a seventh embodiment of the present disclosure. [Figure 8] FIG. 8 shows a schematic cross-sectional view of an aerosol-generating article according to an eighth embodiment of the present disclosure. [Figure 9] FIG. 9 shows a schematic cross-sectional view of an aerosol-generating article according to a ninth embodiment of the present disclosure. [Figure 10] FIG. 10 shows a perspective view of a tubular element according to the present disclosure. [Figure 11] 11A-11D illustrate a method of forming a tubular element according to the present disclosure. [Figure 12] FIG. 12 illustrates an alternative method of forming a tubular element according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0281] 1 shows an aerosol-generating article 1 comprising multiple elements assembled in the form of a rod according to a first embodiment. The multiple elements include 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, extending to a distal end 2 (or upstream end) or a mouth end 3 (or downstream end). The aerosol-generating article 1 has a diameter of about 7 millimeters.

[0282] The aerosol-generating article 1 includes an outer wrapper 40 that surrounds all of the multiple elements assembled in the form of a rod. The outer wrapper 40 is made from 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 approximately 500 micrometers.

[0283] The aerosol-forming substrate 10 comprises an assemblage of a crimped sheet of homogenized tobacco material having a plurality of ridges or corrugations extending substantially parallel to the longitudinal axis of the rod. The assemblage of crimped sheets of homogenized tobacco material extends across substantially the entire transverse cross-sectional area of ​​the aerosol-generating article 1. The aerosol-forming substrate 10 comprises an aerosol former, i.e., glycerol, and has an aerosol former content of about 10 percent on a dry weight basis. 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.

[0284] The first tubular element 20 is positioned within the rod upstream of and adjacent to the second tubular element 30. In this embodiment, the downstream end of the first tubular element 20 is longitudinally spaced from the upstream end of the second tubular element 30. Thus, there is a gap 50 of empty 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 approximately 4 millimeters.

[0285] The first tubular element 20 includes an upstream end wall 21 defining a first opening 22 for allowing fluid communication between the interior of the first tubular element 20 and the exterior of the first tubular element 20. The upstream end wall 21 is formed by a first folded end portion, as described in more detail in connection with Figures 11A-11D. The first opening 22 is located at a radially central location of the upstream end wall 21 and has an equivalent diameter of approximately 3 millimeters.

[0286] 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 toward 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 from 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 of HO.

[0287] The second tubular element 30 includes a second tubular element end wall 31 defining a second opening 32 for allowing fluid communication between the interior of the second tubular element 30 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 and will therefore be referred to as the downstream end wall. The downstream end wall 31 is formed by the second folded end portion. The second opening 32 is located at a radially central location of the downstream end wall 31 and has an equivalent diameter of approximately 3 millimeters.

[0288] The second tubular element 30 is the most downstream element of the aerosol-generating article 1, but 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 about 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 about 6 millimeters and a length of about 12 millimeters. The second tubular element 30 is made from cardboard having a basis weight of about 100 grams per square meter and a thickness of about 1 millimeter. The second tubular element 30 has an RTD of about 40 millimeters HO.

[0289] In use, a heating element from an electrically operated aerosol-generating device is inserted into or positioned around the aerosol-forming substrate 10, heating it and releasing volatile compounds. The consumer inhales on the downstream end 3 of the aerosol-generating article 1 and draws air through the upstream end 2 of the aerosol-generating article 1. As the air is drawn through the aerosol-forming substrate 10, 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 cool and condense 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.

[0290] FIG. 2 shows an aerosol-generating article 1 according to a second embodiment, comprising multiple elements assembled in the form of a rod. The aerosol-generating article 1 of FIG. 2 is similar to the aerosol-generating article 1 of FIG. 1 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 is not in physical contact with 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. Furthermore, 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.

[0291] Figure 3 shows an aerosol-generating article 1 according to a third embodiment, comprising multiple elements assembled in the form of a rod. The aerosol-generating article 1 of Figure 3 is similar to the aerosol-generating article 1 of Figure 1, and also comprises an aerosol-forming substrate 10, a first tubular element 20, and a second tubular element 30. However, 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 and second tubular elements. Furthermore, the second tubular element 30 is positioned at the most downstream end of the aerosol-generating article 1.

[0292] FIG. 4 shows a fourth embodiment of an aerosol-generating article 1 comprising multiple elements assembled in the form of a rod. The first tubular element 20 has a length shorter 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. Furthermore, the first tubular element 20 has a tubular wall thickness smaller 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. Furthermore, the first opening 22 has an equivalent diameter larger 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.

[0293] Figure 5 shows an aerosol-generating article 1 according to a fifth embodiment, comprising a plurality of elements assembled in the form of a rod. The aerosol-generating article 1 of Figure 5 is similar to the aerosol-generating article 1 of Figure 3. However, the aerosol-generating article 1 of Figure 5 further comprises an elongated susceptor element 70.

[0294] An elongated susceptor element 70 is positioned within the aerosol-forming substrate 10. More specifically, the susceptor element 70 is disposed substantially longitudinally within the aerosol-forming substrate 10, such as approximately parallel to the longitudinal axis of the rod. Furthermore, the susceptor element 70 is positioned at a radially central position within the rod and effectively extends along the longitudinal axis of the rod. The susceptor element 70 extends all the way from the upstream end to the downstream end of the aerosol-forming substrate 10. In effect, the susceptor element 70 has substantially the same length as the aerosol-forming substrate 10.

[0295] The susceptor elements 70 are provided in the form of strips having a length of about 12 millimeters, a thickness of about 60 micrometers, and a width of about 4 millimeters.

[0296] 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. Furthermore, the width of the susceptor element 70 is greater than the diameter of the first opening 22 of the first tubular element 20.

[0297] Figure 6 shows an aerosol-generating article 1 according to a sixth embodiment, comprising multiple elements assembled in the form of a rod. The aerosol-generating article 1 of Figure 6 is similar to the aerosol-generating article 1 of Figure 5, but further comprises a front plug 80 and a ventilation zone 90.

[0298] The front plug 70 is located immediately upstream of the aerosol-forming substrate 10. The downstream end of the front plug abuts the upstream end of the aerosol-forming substrate 10. This advantageously prevents the susceptor element 70 from becoming dislodged. Furthermore, this ensures that consumers cannot accidentally come into contact with the heated susceptor element 70 after use.

[0299] The front plug 80 is provided in the form of a cylindrical plug of cellulose acetate surrounded by a hard wrapper. The front plug 80 is about 5 millimeters long and has an RTD of about 30 millimeters H2O.

[0300] The aerosol-generating article 1 comprises a ventilation zone 90 provided at a location between the first tubular element 20 and the second tubular element 30. More specifically, the ventilation zone 90 comprises a plurality of perforations through the outer wrapper 40. The ventilation level of the aerosol-generating article 1 is approximately 40 percent.

[0301] Figure 7 shows an aerosol-generating article 1 according to a seventh embodiment, comprising multiple elements assembled in the form of a rod. The aerosol-generating article 1 of Figure 7 is similar to the aerosol-generating article 1 of Figure 5, but further comprises a ventilation zone 90. More specifically, the ventilation zone 90 is provided approximately 4 millimeters from the downstream end of the second tubular element 30 and comprises 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 percent.

[0302] Figure 8 shows an aerosol-generating article 1 according to an eighth embodiment, comprising a plurality of elements assembled in the form of a rod. The aerosol-generating article 1 of Figure 8 is similar to the aerosol-generating article 1 of Figure 5. However, in the aerosol-generating article 1 of Figure 8, the second element tubular end wall 31 is located at the upstream end of the second tubular element 30.

[0303] 9 shows an aerosol-generating article 1 according to a ninth embodiment, comprising a plurality of elements assembled in the form of a rod, including a first tubular element 20, a second tubular element 30, a capsule 110 containing the aerosol-forming substrate, and a third tubular element 100.

[0304] 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. In addition, the second tubular element 30 is positioned at the most downstream end 3 of the aerosol-generating article 1.

[0305] In this embodiment, there is a third tubular element 100 that is constructed in the same manner as the first tubular element 20 and the second tubular element 30. The third tubular element 100 comprises an upstream end wall 101 that defines a third opening 102 for allowing fluid communication between the interior of the third tubular element 100 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 comprises a cavity 104 that extends from the upstream end wall 101 to the downstream end of the third tubular element 100.

[0306] In contrast to the first to eighth embodiments, in the ninth embodiment, the aerosol-generating article 1 comprises a capsule 110 containing an aerosol-forming substrate in the form of an inhalable dry powder. During use, a 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 assisting in the capsule rupture process. Once the capsule ruptures, the aerosol-forming substrate within the capsule is released when the consumer sucks on the downstream end 3 of the aerosol-generating article 1.

[0307] Figure 10 shows a perspective view of the first tubular element 20 according to Figure 1. 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.

[0308] Figures 11A-11D show a first tubular element 20 for an aerosol-generating article according to the present disclosure through different stages of its formation. These figures therefore show a method of forming a first tubular element, such as the first tubular element 20 of Figure 1. A similar method is used to form a second tubular element of the present disclosure.

[0309] As shown in FIG. 11A, the method begins by providing a tubular element precursor 200 comprising a tubular body 201 defining a cavity 203 extending 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 adjacent to and integrally formed with the first end of the tubular body 201.

[0310] To form the upstream end wall 21, a folding force is applied to the precursor tubular element 200, bending the first end portion 202 around the folding point 204. The folding force deflects the first end portion 202 relative to the tubular body 201 (as indicated by the dashed curved arrow in Figures 11B and 11C) toward the cavity 203. The folding force continues to be applied until the first end portion 202 is folded at an angle greater than 90 degrees, as measured relative to the wall of the tubular body. The folding force is then released. The inherent elastic properties of the paper material (such as paper, paperboard, or corrugated cardboard) of the precursor tubular element 200 cause the first end portion 202 to partially return along its folding path so that it reaches a position where it extends substantially transverse to the longitudinal axis of the tubular body 201. This position is shown in Figure 11D.

[0311] 12 illustrates an alternative method for forming a tubular element according to the present disclosure. In a first step 301, a cellulosic material, such as paper, is mixed with water to form a pulp. Typically, the water has a temperature of about 40 to 70 degrees Celsius. In a second step 302, the pulp is inserted into a mold to produce the desired shape of the tubular element. In a third step 303, the molded pulp is ejected from the mold and dried to remove moisture from the molded pulp, thereby forming the tubular element.

[0312] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like are understood to be modified in all instances by the term "about." Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number A is understood as A ± 5%. Within this context, the number A can be considered to include a numerical value that is within the typical standard error for measurement of the property that the number A modifies. In some cases, as used in the appended claims, the number A may deviate by the percentages recited above, provided that the amount by which A deviates does not materially affect the basic and novel characteristics of the claimed invention. Also, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

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

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

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

4. 4. The aerosol-generating article according to claim 1, wherein the first tubular element and the second tubular element are positioned downstream of the aerosol-forming substrate.

5. 5. The aerosol-generating article of claim 4, wherein any element positioned downstream of the second tubular element has a withdrawal resistance that is less than the withdrawal resistance 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. Any element positioned downstream of the second tubular element may have a diameter of about 10 mmH 2 A withdrawal resistance of less than 0 mmH, preferably about 0 mmH 2 6. The aerosol-generating article according to claim 4 or 5, having a withdrawal resistance of 0.

7. 5. An aerosol-generating article according to claim 1, wherein the second tubular element is the most downstream element of the aerosol-generating article.

8. 8. The aerosol-generating article according to claim 1, wherein the upstream end wall of the first tubular element is in physical contact with the downstream end of the aerosol-forming substrate.

9. An aerosol-generating article according to any preceding claim, wherein the upstream end wall is formed by a first folded end portion and preferably the second tubular element end wall is formed by a second folded end portion.

10. 10. An aerosol-generating article as described in any one of claims 1 to 9, wherein the first tubular element is formed from a first material, the second tubular element is formed from a second material, and the basis weight of the first material is greater than the basis weight of the second material.

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

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

13. 13. The aerosol-generating article according to any one of claims 1 to 12, further comprising a front plug located upstream of the aerosol-forming substrate.

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

15. 15. The aerosol-generating article of any preceding claim, further comprising a susceptor element positioned in thermal contact with the aerosol-forming substrate.

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