RU2842912C1 - Aerosol-generating article with non-homogenised tobacco substrate - Google Patents

Abstract

FIELD: smoking accessories.

SUBSTANCE: aerosol-generating article (10) for producing an inhalable aerosol, when heated, extends from the mouthpiece end to the distal end and comprises: aerosol-generating rod member (12) comprising an aerosol-generating substrate, wherein the aerosol-generating substrate contains an aerosol-forming substance; and downstream section (14) at a point downstream of the aerosol-generating element, wherein the downstream section extending from the downstream end of aerosol-generating element (10) to the mouthpiece end of aerosol-generating article (10). Downstream section comprises hollow tubular element (20). Ratio of length to diameter of element, generating aerosol, ranges from 0.5 to 3.0. Aerosol-generating substrate contains cut tobacco filler; the aerosol-generating substance content in the aerosol-generating substrate is at least 8 % (weight).

EFFECT: possibility of heating the substrate to lower temperatures without compromising the quality and quantity of the aerosol delivered to the consumer, and efficient control of heat transfer through the aerosol-generating element is also provided, due to adaptation of the characteristics of the cut filler and the aerosol content within the aerosol-generating element.

12 cl, 4 dwg

Description

The present invention relates to an aerosol generating article comprising an aerosol generating substrate and adapted to produce an inhalable aerosol upon heating.

Aerosol generating articles in which an aerosol generating substrate, such as a tobacco-containing substrate, is heated rather than burned are known in the art. Typically, in such heated smoking articles, the aerosol is generated by heat transfer from a heat source to a physically separate aerosol generating substrate or material, which may be placed 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 generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol generating article. As the released compounds cool, they condense to form an aerosol.

In a number of prior art documents, aerosol generating devices for consuming aerosol generating articles are disclosed. Such devices include, for example, electrically heated aerosol generating devices, in which the aerosol is generated by transferring heat from one or more electrical heating elements of the aerosol generating device to an aerosol generating substrate of the heated aerosol generating article. For example, electrically heated aerosol generating devices have been proposed, which comprise an internal heating plate, which is adapted to be inserted into an aerosol generating substrate. As an alternative, inductively heated aerosol generating articles have been proposed in WO 2015/176898, comprising an aerosol generating substrate and a current collector, which is located inside the aerosol generating substrate. An additional alternative embodiment has been described in document WO 2020/115151, which discloses an aerosol generating article used in combination with an external heating system comprising one or more heating elements located around the periphery of the aerosol generating article. For example, the external heating elements may be provided in the form of flexible heating foil sheets on a dielectric substrate such as polyimide.

Aerosol-generating articles in which the tobacco-containing substrate is heated rather than combusted create a number of problems that have not been encountered with conventional smoking articles. First, the tobacco-containing substrates are typically heated to significantly lower temperatures than those reached by the combustion front in a conventional cigarette. This may impact the release of nicotine from the tobacco-containing substrate and the delivery of nicotine to the consumer. At the same time, if the heating temperature is increased in an attempt to enhance nicotine delivery, the generated aerosol typically needs to be cooled to a greater extent and more quickly before it reaches the consumer. However, technical solutions that are widely used to cool the mainstream smoke in conventional smoking articles, such as the provision of a highly efficient filtration segment at the mouth end of a cigarette, may have undesirable effects on an aerosol-generating article in which the tobacco-containing substrate is heated rather than combusted, as they may reduce nicotine delivery.

In order to solve one or more problems specifically related to heating, rather than burning, an aerosol-generating substrate to generate an aerosol, a number of aerosol-generating articles have been proposed in which several elements are combined, for example in a longitudinal alignment, with an aerosol-generating element containing an aerosol-generating substrate. As an example, an aerosol-generating element has been combined with a support element to provide improved structural strength to the article, an aerosol-cooling element adapted to reduce the temperature of the aerosol, a low-filtration mouthpiece element, etc.

There is generally a need for aerosol generating products that are easy to use and have improved utility. It would also be desirable to provide aerosol generating products that are easier to manufacture and that can make the entire production chain more balanced and economical. There is also a need for an aerosol generating product that is particularly suitable for use in combination with an external heating system, and in particular one that has improved aerosol generation and delivery of aerosol forming agent.

It would therefore be desirable to provide a new and improved aerosol generating article adapted to satisfy at least one of the needs described above. It would also be desirable to provide one such aerosol generating article that can be manufactured efficiently and at high speed, preferably with a satisfactorily low RTD variability from one article to another.

The present invention relates to an aerosol-generating article for producing an inhalable aerosol by heating, wherein the aerosol-generating article extends from the mouth end to the distal end and comprises an aerosol-generating element. The aerosol-generating element may have the form of a rod. The aerosol-generating element may comprise an aerosol-generating substrate, wherein the aerosol-generating substrate comprises a substance for forming an aerosol. Furthermore, the aerosol-generating article may comprise a downstream section at a location downstream of the aerosol-generating element. The downstream section may extend from the downstream end of the aerosol-generating element to the mouth end of the aerosol-generating article. The downstream section may comprise a hollow tubular element. The length to diameter ratio of the aerosol generating element may be from about 0.5 to about 3.0. The aerosol generating substrate may comprise tobacco shredded filler. The aerosol forming substance content of the aerosol generating substrate may be at least about 8 percent by weight.

According to the present invention, an aerosol-generating article is provided for producing an inhalable aerosol upon heating, wherein the aerosol-generating article extends from the mouth end to the distal end and comprises: an aerosol-generating element comprising an aerosol-generating substrate, wherein the aerosol-generating substrate comprises an aerosol-forming substance; a downstream section at a location downstream of the aerosol-generating element. The downstream section comprises a hollow tubular element. The length-to-diameter ratio of the aerosol-generating element is from about 0.5 to about 3.0. The aerosol-generating substrate comprises tobacco cut filler. The content of the aerosol-forming substance in the aerosol-generating substrate is at least about 8 percent by weight.

The aerosol generating article according to the present invention therefore provides a new configuration of a section of an aerosol generating element, which is characterized by an aerosol generating substrate containing tobacco cut filler and at least about 8 percent by weight of an aerosol forming substance in combination with a specific geometry defined by a length to diameter ratio in the range from about 0.5 to about 3.0. This is further combined with a hollow element at a location downstream of the aerosol generating element, which helps to limit the RTD downstream of the aerosol generating substrate.

The inventors have found that when an aerosol generating article has an aerosol generating element with the geometry described above and a content of a substance for forming an aerosol in the range defined above, it is advantageously possible to optimize the delivery of the aerosol to the consumer, especially if the article is used in combination with an external heating system.

This is desirable because it simplifies the design and operation of both the aerosol generating article and the heating device. It has also been found that it makes it possible to heat the substrate to lower temperatures without compromising the quality and quantity of aerosol delivered to the consumer. By tailoring the characteristics of the cut filler and the aerosol content within the aerosol generating element, it is also possible to precisely and efficiently control the heat transfer through the aerosol generating element.

In addition, the provision of a downstream section containing a hollow tubular element results in a large proportion of the overall RTD of the aerosol generating article being provided by the aerosol generating element itself. Consequently, by adjusting the characteristics of the cut filler, such as particle size, particle size distribution and packing density, the RTD of the aerosol generating element itself and hence the aerosol generating article as a whole can be fine-tuned.

In addition, by providing a hollow element downstream of the aerosol generating rod, a substantially empty volume is provided within the article at a location downstream of the aerosol generating element. Such a substantially empty volume favors the nucleation and growth of aerosol particles. This may further contribute to improving the generation and delivery of aerosol compared to existing articles.

For the purposes of the present specification and the appended claims, except where otherwise indicated, all numbers expressing quantities, amounts, percentages, etc., are to be understood as modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therebetween that may or may not be specifically listed herein. Therefore, in this context, the number A is understood to be A ± 10% of A. In this context, the number A may be considered to include numerical values that are within the common standard error for measuring the property that the number A modifies. The number A, in some instances, when used in the appended claims, may vary by the percentages listed above, provided that the amount by which A varies does not materially affect the essential and novel characteristic(s) of the claimed invention. Also, all ranges include the disclosed high and low points and include any intermediate ranges therebetween that may or may not be specifically listed herein.

According to the present invention, an aerosol generating article is provided for generating an inhalable aerosol upon heating. The aerosol generating article comprises an element comprising an aerosol generating substrate.

The term "aerosol-generating article" is used in this document to refer to an article in which an aerosol-generating substrate is heated to produce and deliver an inhalable aerosol to a user. In the context of this document, the term "aerosol-generating substrate" means a substrate capable of releasing volatile compounds when heated to generate an aerosol.

A conventional cigarette is lit when a user applies a flame to one end of the cigarette and draws air through the other end. The localized heat provided by the flame and oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, and the resulting combustion generates inhaled smoke. By comparison, in heated aerosol-generating articles, the aerosol is generated by heating a flavor-generating substrate, such as tobacco. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which the aerosol is generated by transferring heat from a combustible heat-generating element or heat source to a physically separate aerosol-forming material. For example, the aerosol generating articles according to the present invention find particular application in aerosol generating systems comprising an electrically heated aerosol generating device having an internal heating plate which is adapted to be inserted into a rod of a substrate generating an aerosol. Aerosol generating articles of this type are described in the prior art, for example in document EP 0 822 670.

As used herein, the term "aerosol generating device" refers to a device that includes a heating element that interacts with an aerosol generating substrate of an aerosol generating article to generate an aerosol.

The aerosol generating element may have the form of a rod made of or containing an aerosol generating substrate. In the context of this document, in relation to the present invention, the term "rod" is used to describe a substantially cylindrical element with a substantially circular, oval or elliptical cross-section.

In the context of this document, the term "longitudinal" refers to the direction corresponding to the major longitudinal axis of the aerosol-generating article that extends between the upstream and downstream ends of the aerosol-generating article. In the context of this document, the terms "upstream" and "downstream" describe the relative positions of elements or portions of elements of the aerosol-generating article with respect to the direction in which the aerosol is transported through the aerosol-generating article during use.

During use, air is drawn through the aerosol-generating article in the longitudinal direction. The term "cross" refers to the direction that is perpendicular to the longitudinal axis. Any reference to a "section" of the aerosol-generating article or a component of the aerosol-generating article refers to the cross-section unless otherwise specified.

The term "length" refers to the longitudinal dimension of a component of an aerosol-generating article. For example, it can be used to refer to the longitudinal dimension of a rod or elongated tubular elements.

The aerosol generating article further comprises a downstream section at a location downstream of the aerosol generating substrate rod. As will be apparent from the following description of various embodiments of the aerosol generating article according to the present invention, the downstream section may comprise one or more downstream elements.

In some embodiments, the downstream section may comprise a hollow section between the mouth end of the aerosol-generating article and the aerosol-generating element. The hollow section may comprise a hollow tubular element.

In the context of this document, the term "hollow tubular segment" or "hollow tubular element" is used to designate a generally elongated element that defines a lumen or passage for air flow along its longitudinal axis. In particular, the term "tubular" will be used hereinafter with reference to an element or segment that has a substantially cylindrical cross-section and defines at least one air flow channel that establishes continuous fluid communication between an upstream end of the tubular element or segment and a downstream end of the tubular element or segment. However, it should be understood that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular element or segment may be possible.

In the context of the present invention, the hollow tubular segment or the hollow tubular element provides an unobstructed flow channel. This means that the hollow tubular segment or the hollow tubular element provides an insignificant level of resistance to draw (RTD). The term "insignificant level of RTD" is used to describe an RTD that is less than 1 mm H2O per 10 millimeters of the length of the hollow tubular segment or the hollow tubular element, preferably less than 0.4 mm H2O per 10 millimeters of the length of the hollow tubular segment or the hollow tubular element, more preferably less than 0.1 mm H2O per 10 millimeters of the length of the hollow tubular segment or the hollow tubular element.

Therefore, the flow channel must be free of any components that would impede the longitudinal flow of air. Preferably, the flow channel is substantially empty.

In the present description, a "hollow tubular segment" or "hollow tubular element" may also be referred to as a "hollow tube" or a "hollow tube-shaped segment".

In some embodiments, the aerosol-generating article may comprise a ventilation zone at a location along the downstream section. In more detail, the aerosol-generating article may comprise a ventilation zone at a location along the hollow tubular element. In this way, fluid communication is established between the flow channel formed inside the hollow tubular element and the external environment.

The aerosol generating article may further comprise an upstream section at a location upstream of the aerosol generating substrate rod. The upstream section may comprise one or more upstream elements. In some embodiments, the upstream section may comprise an upstream element located immediately upstream of the aerosol generating element .

As briefly described above, the aerosol generating article according to the present invention comprises a member comprising an aerosol generating substrate.

In some embodiments, the aerosol generating element may be provided in the form of a rod containing an aerosol generating substrate. As an example, the aerosol generating element may comprise a rod of aerosol generating substrate surrounded by a wrapper.

The element containing the aerosol generating substrate may have a length of at least about 5 millimeters. Preferably, the element containing the aerosol generating substrate has a length of at least about 7 millimeters. More preferably, the element containing the aerosol generating substrate has a length of at least about 10 millimeters. In particularly preferred embodiments, the element containing the aerosol generating substrate has a length of at least about 12 millimeters.

The element containing the aerosol generating substrate may have a length of up to approximately 80 millimeters. Preferably, the element containing the aerosol generating substrate has a length that is less than or equal to approximately 65 millimeters. More preferably, the element containing the aerosol generating substrate has a length that is less than or equal to approximately 60 millimeters. Even more preferably, the element containing the aerosol generating substrate has a length that is less than or equal to approximately 55 millimeters.

In particularly preferred embodiments, the element containing the aerosol-generating substrate has a length that is less than or equal to about 50 millimeters, more preferably less than or equal to about 35 millimeters, even more preferably less than or equal to about 25 millimeters. In particularly preferred embodiments, the element containing the aerosol-generating substrate has a length that is less than or equal to about 20 millimeters or even less than or equal to about 15 millimeters.

In some embodiments, the element containing the aerosol-generating substrate has a length of about 5 millimeters to about 60 millimeters, preferably about 6 millimeters to about 60 millimeters, more preferably about 7 millimeters to about 60 millimeters, even more preferably about 10 millimeters to about 60 millimeters, most preferably about 12 millimeters to about 60 millimeters. In other embodiments, the element containing the aerosol-generating substrate has a length of about 5 millimeters to about 55 millimeters, preferably about 6 millimeters to about 55 millimeters, more preferably about 7 millimeters to about 55 millimeters, even more preferably about 10 millimeters to about 55 millimeters, most preferably about 12 millimeters to about 55 millimeters. In further embodiments, the element comprising the aerosol generating substrate has a length of from about 5 millimeters to about 50 millimeters, preferably from about 6 millimeters to about 50 millimeters, more preferably from about 7 millimeters to about 50 millimeters, even more preferably from about 10 millimeters to about 50 millimeters, most preferably from about 12 millimeters to about 50 millimeters.

In some particularly preferred embodiments, the aerosol-generating substrate-containing member has a length of about 5 millimeters to about 30 millimeters, preferably about 6 millimeters to about 30 millimeters, more preferably about 7 millimeters to about 30 millimeters, even more preferably about 10 millimeters to about 30 millimeters. In other particularly preferred embodiments, the aerosol-generating substrate-containing member has a length of about 5 millimeters to about 20 millimeters, preferably about 6 millimeters to about 20 millimeters, more preferably about 7 millimeters to about 20 millimeters, even more preferably about 10 millimeters to about 20 millimeters. In further particularly preferred embodiments, the aerosol-generating substrate-containing element has a length of from about 5 millimeters to about 15 millimeters, preferably from about 7 millimeters to about 20 millimeters, more preferably from about 9 millimeters to about 16 millimeters, even more preferably from about 10 millimeters to about 15 millimeters.

The rod-shaped element containing the aerosol generating substrate preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol generating article.

Preferably, the element containing the aerosol-generating substrate has an outer diameter of at least about 5 millimeters. More preferably, the element containing the aerosol-generating substrate has an outer diameter of at least about 6 millimeters. Even more preferably, the element containing the aerosol-generating substrate has an outer diameter of at least about 7 millimeters.

The element containing the aerosol generating substrate preferably has an outer diameter that is less than or equal to approximately 12 millimeters. More preferably, the element containing the aerosol generating substrate has an outer diameter that is less than or equal to approximately 10 millimeters. Even more preferably, the element containing the aerosol generating substrate has an outer diameter that is less than or equal to approximately 8 millimeters.

In general, it has been observed that the smaller the diameter of the rod-shaped element containing the aerosol-generating substrate, the lower the temperature required to increase the temperature inside the aerosol-generating element so that a sufficient amount of evaporable components are released from the aerosol-generating substrate to form the desired amount of aerosol. At the same time, without being limited by theory, it is understood that a smaller diameter of the rod-shaped element containing the aerosol-generating substrate provides a faster penetration of the heat supplied to the aerosol-generating article throughout the volume of the aerosol-generating substrate. However, when the diameter of the rod-shaped element containing the aerosol-generating substrate is too small, the volume to surface ratio of the aerosol-generating substrate becomes less favorable since the amount of available aerosol-generating substrate decreases.

The diameter of the rod-shaped element containing the aerosol-generating substrate, which is within the ranges described in this document, is particularly advantageous in terms of the balance between energy consumption and aerosol delivery. This advantage is felt in particular when the aerosol-generating article containing the rod containing the aerosol-generating substrate, having a diameter as described in this document, is used in combination with an external heater located along the periphery of the aerosol-generating article. It has been observed that under such operating conditions, less thermal energy is required to achieve a sufficiently high temperature in the core of the rod containing the aerosol-generating substrate and in the core of the article as a whole. Thus, when operating at low temperatures, the desired target temperature in the core of the aerosol-generating substrate can be achieved within a desirably reduced time frame and by means of lower energy consumption.

In some embodiments, the element containing the aerosol-generating substrate has an outer diameter of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 12 millimeters, more preferably about 7 millimeters to about 12 millimeters. In other embodiments, the element containing the aerosol-generating substrate has an outer diameter of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 10 millimeters, more preferably about 7 millimeters to about 10 millimeters. In further embodiments, the element containing the aerosol-generating substrate has an outer diameter of about 5 millimeters to about 8 millimeters, preferably about 6 millimeters to about 8 millimeters, more preferably about 7 millimeters to about 8 millimeters.

In particularly preferred embodiments, the element containing the aerosol-generating substrate has an outer diameter of less than about 7.5 millimeters. As an example, the element containing the aerosol-generating substrate may have an outer diameter of about 7.2 millimeters.

As briefly described above, the ratio of the length to the diameter of the aerosol generating element is at least about 0.5. Preferably, the ratio of the length to the diameter of the aerosol generating element is at least about 0.75. More preferably, the ratio of the length to the diameter of the aerosol generating element is at least about 1.0. Even more preferably, the ratio of the length to the diameter of the aerosol generating element is at least about 1.25.

In addition, the length to diameter ratio of the aerosol generating element is less than or equal to approximately 3.0. Preferably, the length to diameter ratio of the aerosol generating element is less than or equal to approximately 2.75. More preferably, the length to diameter ratio of the aerosol generating element is less than or equal to approximately 2.5. Even more preferably, the length to diameter ratio of the aerosol generating element is less than or equal to approximately 2.25.

In more detail, in the aerosol generating articles according to the present invention, the length to diameter ratio of the aerosol generating element is from about 0.5 to about 3.0.

Preferably, the length to diameter ratio of the aerosol generating element is from about 0.75 to about 3.0. More preferably, the length to diameter ratio of the aerosol generating element is from about 1.0 to about 3.0. Even more preferably, the length to diameter ratio of the aerosol generating element is from about 1.25 to about 3.0.

In other embodiments, the length to diameter ratio of the aerosol generating element may be from about 0.5 to about 2.75. Preferably, the length to diameter ratio of the aerosol generating element is from about 0.75 to about 2.75. More preferably, the length to diameter ratio of the aerosol generating element is from about 1.0 to about 2.75. Even more preferably, the length to diameter ratio of the aerosol generating element is from about 1.25 to about 2.75.

In further embodiments, the length to diameter ratio of the aerosol generating element may be from about 0.5 to about 2.5. Preferably, the length to diameter ratio of the aerosol generating element is from about 0.75 to about 2.5. More preferably, the length to diameter ratio of the aerosol generating element is from about 1.0 to about 2.5. Even more preferably, the length to diameter ratio of the aerosol generating element is from about 1.25 to about 2.5.

In still further embodiments, the length to diameter ratio of the aerosol generating element may be from about 0.5 to about 2.25. Preferably, the length to diameter ratio of the aerosol generating element is from about 0.75 to about 2.25. More preferably, the length to diameter ratio of the aerosol generating element is from about 1.0 to about 2.25. Even more preferably, the length to diameter ratio of the aerosol generating element is from about 1.25 to about 2.25.

In particularly preferred embodiments, the length to diameter ratio of the aerosol generating element may be at least about 1.3, more preferably about 1.4, even more preferably about 1.5.

In particularly preferred embodiments, the length to diameter ratio of the aerosol generating element may be less than or equal to about 2.0, more preferably less than or equal to about 1.9, even more preferably less than or equal to about 1.8.

In some embodiments, the length to diameter ratio of the aerosol generating element is preferably from about 1.3 to about 2.0, more preferably from about 1.4 to about 2.0, even more preferably from about 1.5 to about 2.0. In other embodiments, the length to diameter ratio of the aerosol generating element is preferably from about 1.3 to about 1.9, more preferably from about 1.4 to about 1.9, even more preferably from about 1.5 to about 1.9. In further embodiments, the length to diameter ratio of the aerosol generating element is preferably from about 1.3 to about 1.8, more preferably from about 1.4 to about 1.8, even more preferably from about 1.5 to about 1.8.

The ratio between the length of the aerosol generating element and the total length of the aerosol generating article may be at least about 0.10. Preferably, the ratio between the length of the aerosol generating element and the total length of the aerosol generating article is at least about 0.15. More preferably, the ratio between the length of the aerosol generating element and the total length of the aerosol generating article is at least about 0.20. Even more preferably, the ratio between the length of the aerosol generating element and the total length of the aerosol generating article is at least about 0.25.

In general, the ratio between the length of the aerosol generating element and the overall length of the aerosol generating article may be less than or equal to about 0.60. Preferably, the ratio between the length of the aerosol generating element and the overall length of the aerosol generating article is less than or equal to about 0.50. More preferably, the ratio between the length of the aerosol generating element and the overall length of the aerosol generating article is less than or equal to about 0.45. Even more preferably, the ratio between the length of the aerosol generating element and the overall length of the aerosol generating article is less than or equal to about 0.40. In particularly preferred embodiments, the ratio between the length of the aerosol generating element and the overall length of the aerosol generating article is less than or equal to about 0.35 and most preferably less than or equal to about 0.30.

In some embodiments, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is from about 0.10 to about 0.45, preferably from about 0.15 to about 0.45, more preferably from about 0.20 to about 0.45, even more preferably from about 0.25 to about 0.45. In other embodiments, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is from about 0.10 to about 0.40, preferably from about 0.15 to about 0.40, more preferably from about 0.20 to about 0.40, even more preferably from about 0.25 to about 0.40. In further embodiments, the ratio between the length of the aerosol generating element and the overall length of the aerosol generating article is from about 0.10 to about 0.35, preferably from about 0.15 to about 0.35, more preferably from about 0.20 to about 0.35, even more preferably from about 0.25 to about 0.35. In still further embodiments, the ratio between the length of the aerosol generating element and the overall length of the aerosol generating article is from about 0.10 to about 0.30, preferably from about 0.15 to about 0.30, more preferably from about 0.20 to about 0.30, even more preferably from about 0.25 to about 0.30.

Preferably, the aerosol generating element comprises a rod-shaped element comprising an aerosol generating substrate, which has a substantially uniform cross-section along the length of the element. Particularly preferably, the rod-shaped element comprising an aerosol generating substrate has a substantially circular cross-section.

As will be described in more detail below, the aerosol generating article according to the present invention comprises a downstream section comprising a hollow tubular element. In the aerosol generating article according to the present invention, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be less than or equal to approximately 0.66. Preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be less than or equal to approximately 0.60. More preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be less than or equal to approximately 0.50. Even more preferably, the ratio between the length of the aerosol generating element and the length of the hollow tubular element may be less than or equal to approximately 0.40.

In the aerosol-generating article according to the present invention, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.10. Preferably, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.15. More preferably, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.20. Even more preferably, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.25. In particularly preferred embodiments, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.30.

In some embodiments, the ratio between the length of the aerosol generating element and the length of the hollow tubular element is from about 0.15 to about 0.60, preferably from about 0.20 to about 0.60, more preferably from about 0.25 to about 0.60, even more preferably from about 0.30 to about 0.60. In other embodiments, the ratio between the length of the aerosol generating element and the length of the hollow tubular element is from about 0.15 to about 0.50, preferably from about 0.20 to about 0.50, more preferably from about 0.25 to about 0.50, even more preferably from about 0.30 to about 0.50. In further embodiments, the ratio between the length of the aerosol generating element and the length of the hollow tubular element is from about 0.15 to about 0.40, preferably from about 0.20 to about 0.40, more preferably from about 0.25 to about 0.40, even more preferably from about 0.30 to about 0.40. As an example, the ratio between the length of the aerosol generating element and the length of the hollow tubular element can be about 0.35.

The density of the aerosol generating substrate may be at least about 100 micrograms/cubic centimeter. Preferably, the density of the aerosol generating substrate is at least about 115 micrograms/cubic centimeter. More preferably, the density of the aerosol generating substrate is at least about 130 micrograms/cubic centimeter. Even more preferably, the density of the aerosol generating substrate is at least about 140 micrograms/cubic centimeter.

The density of the aerosol generating substrate may be less than or equal to about 200 micrograms/cubic centimeter. Preferably, the density of the aerosol generating substrate is less than or equal to about 185 micrograms/cubic centimeter. More preferably, the density of the aerosol generating substrate is less than or equal to about 170 micrograms/cubic centimeter. Even more preferably, the density of the aerosol generating substrate is less than or equal to about 160 micrograms/cubic centimeter.

In some embodiments, the density of the aerosol generating substrate is from 100 micrograms/cubic centimeter to 200 micrograms/cubic centimeter, preferably from 100 micrograms/cubic centimeter to 185 micrograms/cubic centimeter, more preferably from 100 micrograms/cubic centimeter to 170 micrograms/cubic centimeter, even more preferably from 100 micrograms/cubic centimeter to 160 micrograms/cubic centimeter. In other embodiments, the density of the aerosol generating substrate is from 115 micrograms/cubic centimeter to 200 micrograms/cubic centimeter, preferably from 115 micrograms/cubic centimeter to 185 micrograms/cubic centimeter, more preferably from 115 micrograms/cubic centimeter to 170 micrograms/cubic centimeter, even more preferably from 115 micrograms/cubic centimeter to 160 micrograms/cubic centimeter. In further embodiments, the density of the aerosol generating substrate is from 130 micrograms/cubic centimeter to 200 micrograms/cubic centimeter, preferably from 130 micrograms/cubic centimeter to 185 micrograms/cubic centimeter, more preferably from 130 micrograms/cubic centimeter to 170 micrograms/cubic centimeter, even more preferably from 130 micrograms/cubic centimeter to 160 micrograms/cubic centimeter. In yet other embodiments, the density of the aerosol generating substrate is from 140 micrograms/cubic centimeter to 200 micrograms/cubic centimeter, preferably from 140 micrograms/cubic centimeter to 185 micrograms/cubic centimeter, more preferably from 140 micrograms/cubic centimeter to 170 micrograms/cubic centimeter, even more preferably from 140 micrograms/cubic centimeter to 160 micrograms/cubic centimeter. In some particularly preferred embodiments, the density of the aerosol generating substrate is approximately 150 micrograms/cubic centimeter.

The density of the aerosol generating substrate may be at least about 100 milligrams/cubic centimeter. Preferably, the density of the aerosol generating substrate is at least about 115 milligrams/cubic centimeter. More preferably, the density of the aerosol generating substrate is at least about 130 milligrams/cubic centimeter. Even more preferably, the density of the aerosol generating substrate is at least about 140 milligrams/cubic centimeter.

The density of the aerosol generating substrate may be less than or equal to about 200 milligrams/cubic centimeter. Preferably, the density of the aerosol generating substrate is less than or equal to about 185 milligrams/cubic centimeter. More preferably, the density of the aerosol generating substrate is less than or equal to about 170 milligrams/cubic centimeter. Even more preferably, the density of the aerosol generating substrate is less than or equal to about 160 milligrams/cubic centimeter.

In some embodiments, the density of the aerosol generating substrate is from 100 milligrams/cubic centimeter to 200 milligrams/cubic centimeter, preferably from 100 milligrams/cubic centimeter to 185 milligrams/cubic centimeter, more preferably from 100 milligrams/cubic centimeter to 170 milligrams/cubic centimeter, even more preferably from 100 milligrams/cubic centimeter to 160 milligrams/cubic centimeter. In other embodiments, the density of the aerosol generating substrate is from 115 milligrams/cubic centimeter to 200 milligrams/cubic centimeter, preferably from 115 milligrams/cubic centimeter to 185 milligrams/cubic centimeter, more preferably from 115 milligrams/cubic centimeter to 170 milligrams/cubic centimeter, even more preferably from 115 milligrams/cubic centimeter to 160 milligrams/cubic centimeter. In further embodiments, the density of the aerosol generating substrate is from 130 milligrams/cubic centimeter to 200 milligrams/cubic centimeter, preferably from 130 milligrams/cubic centimeter to 185 milligrams/cubic centimeter, more preferably from 130 milligrams/cubic centimeter to 170 milligrams/cubic centimeter, even more preferably from 130 milligrams/cubic centimeter to 160 milligrams/cubic centimeter. In still other embodiments, the density of the aerosol-generating substrate is from 140 milligrams/cubic centimeter to 200 milligrams/cubic centimeter, preferably from 140 milligrams/cubic centimeter to 185 milligrams/cubic centimeter, more preferably from 140 milligrams/cubic centimeter to 170 milligrams/cubic centimeter, even more preferably from 140 milligrams/cubic centimeter to 160 milligrams/cubic centimeter. In some particularly preferred embodiments, the density of the aerosol-generating substrate is about 150 milligrams/cubic centimeter.

As an example, the aerosol generating element may comprise from about 100 milligrams to about 250 milligrams of aerosol generating substrate. In some embodiments, the aerosol generating element comprises from about 210 milligrams to about 230 milligrams of aerosol generating substrate, preferably from 215 milligrams to about 220 milligrams of aerosol generating substrate. In other embodiments, the aerosol generating element comprises from about 150 milligrams to about 180 milligrams of aerosol generating substrate, preferably from 160 milligrams to about 165 milligrams of aerosol generating substrate.

In the aerosol generating articles according to the present invention, the aerosol generating substrate is a solid aerosol generating substrate. In more detail, as briefly described above, the aerosol generating substrate comprises a cut filler.

In the context of this technical description, the term "cut filler" is used to describe a mixture of ground plant material, such as tobacco plant material, including in particular one or more of leaf blades, processed stems and veins, homogenized plant material.

In the context of this document, the term "homogenized plant material" encompasses any plant material formed by agglomerating plant particles. For example, sheets or webs of homogenized tobacco material for aerosol-generating substrates according to the present invention may be formed by agglomerating tobacco material particles obtained by grinding, milling or crushing plant material and optionally one or more of tobacco leaf lamellas and tobacco leaf veins. The homogenized plant material may be obtained by casting processes, extrusion processes, papermaking processes or any other suitable methods known in the art.

Cut filler may also contain other trimmings, filler tobacco or casing.

Preferably, the cut filler comprises at least 25 percent of plant leaf blades, more preferably at least 50 percent of plant leaf blades, even more preferably at least 75 percent of plant leaf blades, and most preferably at least 90 percent of plant leaf blades. Preferably, the plant material is one of tobacco, mint, tea, and cloves. However, as will be described in more detail below, the present invention is equally applicable to other plant material that has the ability to release substances upon application of heat, which can subsequently form an aerosol.

Preferably, the cut filler comprises tobacco plant material comprising leaf blades of one or more of light tobacco, dark tobacco, aromatic tobacco and filler tobacco. In the context of the present invention, the term "tobacco" describes any plant belonging to the genus Nicotiana.

Light tobacco is a tobacco with generally large leaves that are light in color. Throughout the technical description, the term light tobacco is used for tobacco that has been flue-cured. Examples of light tobacco are Chinese flue-cured tobacco, Brazilian flue-cured tobacco, American flue-cured tobacco such as Virginia tobacco, Indian flue-cured tobacco, Tanzanian flue-cured tobacco, or other African flue-cured tobacco. Light tobacco is characterized by a high sugar to nitrogen ratio. From an organoleptic standpoint, light tobacco is a type of tobacco that, after curing, is associated with a spicy and rich sensation. In the context of the present invention, light tobacco is tobacco with a reducing sugar content of about 2.5 percent to about 20 percent based on the dry weight of the leaf and a total ammonia content of less than about 0.12 percent based on the dry weight of the leaf. Reducing sugars include, for example, glucose or fructose. The total ammonia content includes, for example, ammonia and ammonia salts.

Dark tobacco is tobacco with typically large, dark colored leaves. Throughout the technical description, the term "dark tobacco" is used for tobacco that has been air-cured. Additionally, dark tobacco may be fermented. Tobacco that is used primarily for chewing, snuff, cigars, and pipe blends is also included in this category. Typically, this dark tobacco is air-cured and possibly fermented. From an organoleptic point of view, dark tobacco is a type of tobacco that, after curing, is associated with a sensation similar to that of the smoke of dark cigars. Dark tobacco is characterized by a low sugar to nitrogen ratio. Examples of dark tobacco are Malawi Burley or other African Burley, dark cured Brazilian Galpao, and sun-cured or air-cured Indonesian Kasturi. According to the present invention, dark tobacco is tobacco with a reducing sugar content of less than about 5 percent based on the dry weight of the leaf and a total ammonia content of up to about 0.5 percent based on the dry weight of the leaf.

Aromatic tobacco is a tobacco that often has small, light-colored leaves. Throughout the technical description, the term "aromatic tobacco" is used to refer to other tobaccos that are characterized by a high content of aromatic substances, such as essential oils. From an organoleptic point of view, aromatic tobacco is a type of tobacco that, after curing, is associated with a spicy and aromatic sensation. Examples of aromatic tobaccos are Greek Oriental tobacco, Turkish Oriental tobacco, semi-Oriental tobacco, and fire-cured tobaccos, American Burley such as Perique, Shag, American Burley, or Maryland. Filler tobacco is not a specific type of tobacco, but includes types of tobacco that are primarily used to complement other types of tobacco used in a blend and that do not impart a specific characteristic aromatic property to the final product. Examples of filler tobacco are the stems, midribs, or petioles of other types of tobacco. A specific example is the flue-cured stems from the lower petioles of the Brazilian flue-cured tobacco species.

The cut filler suitable for use in the present invention may generally resemble the cut filler used for conventional smoking articles. The cut width of the cut filler is preferably from 0.3 millimeters to 2.0 millimeters, more preferably the cut width of the cut filler is from 0.5 millimeters to 1.2 millimeters, and most preferably the cut width of the cut filler is from 0.6 millimeters to 0.9 millimeters. The cut width may play a role in the distribution of heat within the aerosol generating element. Also, the cut width may play a role in the resistance to draw of the article. In addition, the cut width may affect the overall density of the aerosol generating substrate as a whole.

The length of the threads of the cut filler is to some extent a random value, since the length of the threads will depend on the overall size of the object from which the thread is cut. However, by maintaining appropriate conditions for the material before cutting, for example, by controlling the moisture content and the overall fineness of the material, longer threads can be cut. Preferably, the threads have a length of from about 10 millimeters to about 40 millimeters before the threads are combined to form the aerosol generating element. Obviously, if the threads are located in the aerosol generating element in a longitudinal extension, where the longitudinal extension of the section is less than 40 millimeters, the final aerosol generating element can contain threads that are on average shorter than the length of the original thread. Preferably, the length of the thread of the cut filler is such that from about 20 percent to 60 percent of the threads extend along the entire length of the aerosol generating element. This prevents the threads from easily separating from the aerosol generating element.

In preferred embodiments, the weight of the cut filler is from 80 milligrams to 400 milligrams, preferably from 150 milligrams to 250 milligrams, more preferably from 170 milligrams to 220 milligrams. This amount of cut filler usually allows to obtain enough material to form an aerosol. Additionally, in light of the above-mentioned limitations on diameter and size, this ensures a balanced density of the aerosol generating element between energy absorption, resistance to draw and fluid passages in the aerosol generating element, where the aerosol generating substrate contains plant material.

Preferably, the cut filler is impregnated with an aerosol forming agent. Impregnation of the cut filler can be carried out by spraying or other suitable application methods. The aerosol forming agent can be added to the mixture when preparing the cut filler. For example, the aerosol forming agent can be added to the mixture in a direct conditioning housing cylinder (DCCC). Conventional equipment can be used to add the aerosol forming agent to the cut filler. The aerosol forming agent can be any suitable known compound or mixture of compounds that facilitates the formation of a dense and stable aerosol when used. The aerosol forming agent can provide substantially resistance of the aerosol to thermal degradation at temperatures typically encountered when using the aerosol-generating article. Suitable aerosol forming substances are, for example: polyhydric alcohols, such as, for example, triethylene glycol, 1,3-butanediol, propylene glycol and glycerol; esters of polyhydric alcohols, such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids, such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol forming agent comprises one or more of glycerin and propylene glycol. The aerosol forming agent may consist of glycerin or propylene glycol or a combination of glycerin and propylene glycol.

As briefly described above, in the aerosol-generating articles according to the present invention, the content of the aerosol-forming substance in the aerosol-generating substrate is at least about 8 percent by weight based on the dry weight of the cut filler. Preferably, the content of the aerosol-forming substance in the aerosol-generating substrate is less than or equal to about 20 percent by weight based on the dry weight of the cut filler.

Preferably, the amount of aerosol forming agent is from 8 percent to 18 percent by weight based on the dry weight of the cut filler, most preferably, the amount of aerosol forming agent is from 10 percent to 15 percent by weight based on the dry weight of the cut filler. In some embodiments, the amount of aerosol forming agent has a target value of about 13 percent by weight based on the dry weight of the cut filler. The most effective amount of aerosol forming agent will also depend on the cut filler, regardless of whether the cut filler contains plant leaf blades or homogenized plant material. For example, among other factors, the type of cut filler will determine the extent to which the aerosol forming agent can facilitate the release of substances from the cut filler.

For these reasons, an aerosol generating element containing cut filler as described above is capable of efficiently generating sufficient amounts of aerosol at relatively low temperatures. Temperatures of 150 degrees Celsius to 200 degrees Celsius in the heating chamber are sufficient for one such cut filler to generate sufficient amounts of aerosol, while aerosol generating devices that use sheets of molded tobacco leaves typically use temperatures of approximately 250 degrees Celsius.

An additional benefit associated with operating at lower temperatures is that the need for aerosol cooling is reduced. Since low temperatures are typically used, a simpler cooling function may be sufficient. This, in turn, allows for a simpler and less complex design of the aerosol generating product.

Preferably, when the aerosol generating substrate comprises a cut filler obtained, for example, by a cutting or grinding operation, from a homogenized plant material, the homogenized plant material is provided in the form of sheets. As an example, sheets of homogenized plant material can be obtained by a casting process or by a paper manufacturing process.

Each of the sheets individually, as described herein, may have a thickness of from about 100 micrometers to 600 micrometers, preferably from 150 micrometers to 300 micrometers, and most preferably from 200 micrometers to 250 micrometers.

Each of the sheets individually, as described herein, may have a square meter weight of from about 100 grams per square meter to about 300 grams per square meter.

Each of the sheets individually, as described herein, may have a density of from approximately 0.3 grams per cubic centimeter up to about 1.3 grams per cubic centimeter and preferably from about 0.7 grams per cubic centimeter to about 1.0 grams per cubic centimeter.

The homogenized plant material may contain up to about 95 percent by weight of plant particles on a dry weight basis. Preferably, the homogenized plant material contains up to about 90 percent by weight of plant particles, more preferably up to about 80 percent by weight of plant particles, more preferably up to about 70 percent by weight of plant particles, more preferably up to about 60 percent by weight of plant particles, more preferably up to about 50 percent by weight of plant particles on a dry weight basis.

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

In certain embodiments of the present invention, the homogenized plant material is a homogenized tobacco material comprising tobacco particles. Sheets of homogenized tobacco material for use in such embodiments of the present invention may have a tobacco content of at least about 40 percent by weight on a dry basis, more preferably at least about 50 percent by weight on a dry basis, more preferably at least about 70 percent by weight on a dry basis, and most preferably at least about 90 percent by weight on a dry basis.

In relation to homogenized plant material in the context of the present invention, the term "tobacco particles" describes particles of any plant belonging to the genus Nicotiana . The term "tobacco particles" includes ground or powdered tobacco leaf lamellas, ground or powdered tobacco leaf stems, tobacco dust, tobacco fines and other tobacco by-products in the form of particles that are generated during the processing, handling and shipping of tobacco. In a preferred embodiment, the tobacco particles are substantially all derived from tobacco leaf lamellas. In contrast, separated nicotine and nicotine salts are compounds derived from tobacco, but are not considered tobacco particles for the purposes of the present invention and are not included in the percentage of particulate plant material.

The tobacco particles may be derived from one or more varieties of tobacco plants. Any type of tobacco may be used in the blend. Examples of types of tobacco that may be used include, but are not limited to, sun-cured tobacco, flue-cured tobacco, Burley tobacco, Maryland tobacco, Oriental tobacco, Virginia tobacco, and other specialty tobaccos.

Flue-curing is a method of drying tobacco that is especially used with Virginia tobacco. During the flue-curing process, heated air is circulated through tightly packed tobacco. During the first stage, the tobacco leaves turn yellow and wither. During the second stage, the leaf blades are completely dry. During the third stage, the leaf stems are completely dry.

Burley tobacco plays an important role in many tobacco blends. Burley tobacco has a recognizable flavor and aroma, and also has the ability to absorb large amounts of sauce.

Oriental tobacco is a tobacco that has small leaves and pronounced aromatic qualities. However, oriental tobacco has a milder flavor than, for example, Burley tobacco. Therefore, in general, oriental tobacco is used in relatively small proportions in tobacco blends.

Kasturi, Maduro and Yatim are subtypes of sun-cured tobacco that can be used. Preferably, Kasturi tobacco and flue-cured tobacco can be used in a mixture to produce tobacco particles. Accordingly, the tobacco particles in the particulate plant material can comprise a mixture of Kasturi tobacco and flue-cured tobacco.

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

In certain other embodiments of the present invention, the homogenized plant material comprises tobacco particles in combination with non-tobacco plant flavor particles. Preferably, the non-tobacco plant flavor particles are selected from one or more of: ginger particles, eucalyptus particles, anise particles, and star anise particles. Preferably, in such embodiments, the homogenized plant material comprises at least about 2.5 percent by weight of non-tobacco plant flavor particles on a dry weight basis, with the remainder of the plant particles being tobacco particles. Preferably, the homogenized plant material comprises at least about 4 percent by weight of non-tobacco plant flavor particles, more preferably at least about 6 percent by weight of non-tobacco plant flavor particles, more preferably at least about 8 percent by weight of non-tobacco plant flavor particles, and more preferably at least about 10 percent by weight of non-tobacco plant flavor particles, based on dry weight. Preferably, the homogenized plant material comprises up to about 20 percent by weight of non-tobacco plant flavor particles, more preferably up to about 18 percent by weight of non-tobacco plant flavor particles, more preferably up to about 16 percent by weight of non-tobacco plant flavor particles.

The weight ratio of the non-tobacco plant flavouring particles to the tobacco particles in the particulate plant material forming the homogenised plant material may vary depending on the desired flavour characteristics and the composition of the aerosol obtained from the aerosol generating substrate during use. Preferably, the homogenised plant material comprises at least a weight ratio of 1:30 of the non-tobacco plant flavouring particles to the tobacco particles, more preferably at least a weight ratio of 1:20 of the non-tobacco plant flavouring particles to the tobacco particles, more preferably at least a weight ratio of 1:10 of the non-tobacco plant flavouring particles to the tobacco particles, and most preferably at least a weight ratio of 1:5 of the non-tobacco plant flavouring particles to the tobacco particles, based on dry weight.

Alternatively or additionally to the inclusion of tobacco particles in the homogenized plant material of the aerosol generating substrate according to the present invention, the homogenized plant material may comprise hemp particles. The term "hemp particles" refers to particles of the hemp plant, for example, the species Cannabis sativa, Cannabis indica and Cannabis ruderalis .

The homogenized plant material preferably comprises no more than 95 percent by weight of particulate plant material on a dry weight basis. Therefore, the particulate plant material is typically combined with one or more other components to form the homogenized plant material.

The homogenized plant material may further comprise a binder for changing the mechanical properties of the particulate plant material, wherein the binder is incorporated into the homogenized plant material during manufacture as described herein. Suitable exogenous binders are known to those skilled in the art and include, but are not limited to: gums such as, for example, guar gum, xanthan gum, acacia and locust bean gum; cellulose binders such as, for example, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose and ethyl cellulose; polysaccharides such as, for example, starches, organic acids such as alginic acid, salts of conjugate bases with organic acids such as sodium alginate, agar and pectins; and combinations thereof. Preferably, the binder comprises guar gum.

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

Alternatively or additionally, the homogenized plant material may further comprise one or more lipids that promote the diffusibility of volatile components (e.g., aerosol forming agents, gingerols, and nicotine), wherein the lipid is included in the homogenized plant material during manufacture as described herein. Lipids suitable for inclusion in the homogenized plant material include, but are not limited to: medium chain triglycerides, cocoa butter, palm oil, palm kernel oil, mango butter, shea butter, soybean oil, cottonseed oil, coconut oil, hydrogenated coconut oil, candelilla wax, carnauba wax, shellac, sunflower wax, sunflower oil, rice bran, Revel A, and combinations thereof.

Alternatively or additionally, the homogenized plant material may further comprise a pH modifier.

Alternatively or additionally, the homogenized plant material may further comprise fibers to alter the mechanical properties of the homogenized plant material, wherein the fibers are incorporated into the homogenized plant material during manufacture as described herein. Suitable exogenous fibers for inclusion in the homogenized plant material are known in the art and include fibers derived from non-tobacco material and material other than ginger, including but not limited to: cellulose fibers; softwood fibers; hardwood fibers; jute fibers, and combinations thereof. Exogenous fibers derived from tobacco and/or ginger may also be added. Any fibers added to the homogenized plant material are not considered to form part of the "particulate plant material" as defined above. Prior to incorporation into the homogenized plant material, the fibers may be processed by suitable methods known in the art, including but not limited to: mechanical pulping; cleaning; chemical pulping; bleaching; sulphate pulping; and combinations thereof. The fibre is usually longer than it is wide.

Suitable fibers typically have a length greater than 400 micrometers and less than or equal to 4 millimeters, preferably in the range of 0.7 millimeters to 4 millimeters. Preferably, the fibers are present in an amount of from about 2 percent to about 15 percent by weight, most preferably in an amount of about 4 percent by weight, based on the dry weight of the substrate.

Alternatively or additionally, the homogenized plant material may further comprise one or more aerosol forming agents. After vaporization, the aerosol forming agent may carry other vaporized compounds released from the aerosol generating substrate upon heating, such as nicotine and flavoring agents, in the aerosol. Aerosol forming agents suitable 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 dimethyl tetradecanedioate.

The homogenized plant material may have an aerosol forming agent content of from about 5 percent to about 30 percent by weight on a dry weight basis, such as from about 10 percent to about 25 percent by weight on a dry weight basis or from about 15 percent to about 20 percent by weight on a dry weight basis.

For example, if the substrate is intended for use in an aerosol-generating article for an electrical aerosol-generating system having a heating element, it may preferably comprise an aerosol-forming substance content of from about 5 percent to about 30 percent by weight on a dry weight basis. If the substrate is intended for use in an aerosol-generating article for an electrical aerosol-generating system having a heating element, the aerosol-forming substance is preferably glycerol.

In other embodiments, the homogenized plant material may have an aerosol forming agent content of from 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 forming agent is retained in a reservoir separate from the substrate, the substrate may have an aerosol forming agent content of greater than 1 percent and less than about 5 percent. In such embodiments, the aerosol forming agent is vaporized by heating and a stream of the aerosol forming agent contacts the aerosol-generating substrate to entrain flavoring substances from the aerosol-generating substrate in the aerosol.

In other embodiments, the homogenized plant material may have an aerosol former content of from about 30 percent by weight to about 45 percent by weight. This relatively high level of aerosol former is particularly suitable for aerosol-generating substrates that are intended to be heated at a temperature of less than 275 degrees Celsius. In such embodiments, the homogenized plant material preferably further comprises from about 2 percent by weight to about 10 percent by weight of a cellulose ether on a dry weight basis and from about 5 percent by weight to about 50 percent by weight of additional cellulose on a dry weight basis. It has been found that the use of a combination of a cellulose ether and additional cellulose provides particularly effective aerosol delivery when used in an aerosol-generating substrate having an aerosol former content of from 30 percent by weight to 45 percent by weight.

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

As used herein, the term "additional cellulose" encompasses any cellulosic material included in the homogenized plant material that does not originate from non-tobacco plant particles or tobacco particles provided in the homogenized plant material. Therefore, the additional cellulose is included in the homogenized plant material in addition to the non-tobacco plant material or tobacco material as a source of cellulose separate and distinct from any cellulose inherently present in the non-tobacco plant particles or tobacco particles. The additional cellulose typically originates from a plant other than the non-tobacco plant particles or tobacco particles. Preferably, the additional cellulose is in the form of an inert cellulosic material that is inert to the senses and therefore does not significantly affect the organoleptic characteristics of the aerosol generated from the aerosol generating substrate. For example, the additional cellulose is preferably a tasteless and odorless material.

Supplementary cellulose may contain cellulose powder, cellulose fibers, or a combination of both.

The aerosol forming agent can act as a humectant in the aerosol generating substrate.

The wrapper surrounding the rod of homogenized plant material may be a paper wrapper or a non-paper wrapper. Paper wrappers suitable for use in particular embodiments of the present invention are known in the art and include, but are not limited to, cigarette paper and filter papers. Non-paper wrappers suitable for use in particular embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco materials. In certain preferred embodiments, the wrapper may be formed from a laminated material comprising a plurality of layers. Preferably, the wrapper is formed from a multi-layer sheet comprising a layer of aluminum. The use of a multi-layer sheet comprising aluminum advantageously prevents combustion of the aerosol-generating substrate in the event that the aerosol-generating substrate is to be ignited rather than heated in the intended manner.

The downstream section may have any length. The downstream section may have a length of at least about 10 millimeters. For example, the downstream section may have a length of at least about 15 millimeters, at least about 20 millimeters, at least about 25 millimeters, or at least about 30 millimeters.

Providing a downstream section that has a length that is greater than the values set out above can advantageously provide space for the aerosol to cool and condense before reaching the consumer. It can also provide distance between the user and the heating element when the aerosol generating article is used in conjunction with the aerosol generating device.

The downstream section may have a length of no more than about 60 millimeters. For example, the downstream section may have a length of no more than about 50 millimeters, no more than about 55 millimeters, no more than about 40 millimeters, or no more than about 35 millimeters.

The downstream section may have a length of about 10 millimeters to about 60 millimeters, about 15 millimeters to about 50 millimeters, about 20 millimeters to about 55 millimeters, about 25 millimeters to about 40 millimeters, or about 30 millimeters to about 35 millimeters. For example, the downstream section may have a length of about 33 millimeters.

The ratio between the length of the downstream section and the length of the element containing the aerosol generating substrate may be from about 1.0 to about 4.5.

Preferably, the ratio between the length of the downstream section and the length of the aerosol generating element is at least about 1.5, more preferably at least about 2.0, even more preferably at least about 2.5. In preferred embodiments, the ratio between the length of the downstream section and the length of the aerosol generating element is less than about 4.0, more preferably less than about 3.5, even more preferably less than about 3.0.

In some embodiments, the ratio between the length of the downstream section and the length of the aerosol generating element is from about 1.5 to about 4.0, preferably from about 2.0 to about 3.5, more preferably from about 2.5 to about 3.0.

In particularly preferred embodiments, the ratio between the length of the downstream section and the length of the aerosol generating element is approximately 2.75.

The ratio between the length of the downstream section and the overall length of the aerosol generating article may be from about 0.1 to about 1.5.

Preferably, the ratio between the length of the downstream section and the total length of the aerosol generating article is at least about 0.25, more preferably at least about 0.50. The ratio between the length of the downstream section and the total length of the aerosol generating article is preferably less than about 1.25, more preferably less than about 1.0.

In some embodiments, the ratio between the length of the downstream section and the overall length of the aerosol generating article is preferably from about 0.25 to about 1.25, more preferably from about 0.5 to about 1.0.

In a particularly preferred embodiment, the ratio between the length of the downstream section and the overall length of the aerosol generating article is approximately 0.73.

The length of the downstream section may consist of the sum of the lengths of the individual components that form the downstream section.

The RTD of the downstream section may be no more than about 100 mmH2O. For example, the RTD of the upstream section may be no more than about 50 mmH2O, no more than about 25 mmH2O, no more than about 15 mmH2O, no more than about 10 mmH2O, no more than about 8 mmH2O, no more than about 5 mmH2O, or no more than about 1 mmH2O. The RTD of the downstream section will also be discussed in more detail below.

The downstream section may comprise an unobstructed path for air flow from the downstream end of the aerosol generating substrate to the downstream end of the downstream section.

The unobstructed air flow path from the downstream end of the aerosol generating substrate to the downstream end of the downstream section has a minimum diameter of approximately 0.5 millimeters.

In the aerosol generating articles of the present invention, the downstream section comprises a hollow tube-shaped segment.

Providing a hollow segment in the form of a tube can advantageously provide the desired overall length of the aerosol generating article without unacceptably increasing the draw resistance.

The hollow tube may extend from the downstream end of the downstream section to the upstream end of the downstream section. In other words, the entire length of the downstream section may be comprised of a hollow tube segment. When this is the case, it will be understood that the lengths and length ratios stated above relative to the downstream section apply equally to the length of the hollow tube segment.

The hollow tube segment may have an internal diameter. The hollow tube segment may have a constant internal diameter along the length of the hollow tube segment. The internal diameter of the hollow tube segment may vary along the length of the hollow tube segment.

The hollow tube segment may have an internal diameter of at least about 2 millimeters. For example, the hollow tube segment may have an internal diameter of at least about 4 millimeters, at least about 5 millimeters, or at least about 7 millimeters.

Providing a hollow segment in the form of a tube having an inner diameter as described above can advantageously ensure sufficient rigidity and strength for the hollow segment in the form of a tube.

The hollow tube segment may have an internal diameter of no more than about 10 millimeters. For example, the hollow tube segment may have an internal diameter of no more than about 9 millimeters, no more than about 8 millimeters, or no more than about 7.5 millimeters.

Providing the hollow segment in the form of a tube having an inner diameter as described above can advantageously reduce the tightening resistance of the hollow tubular segment.

The hollow tube segment may have an internal diameter of from about 2 millimeters to about 10 millimeters, from about 4 millimeters to about 9 millimeters, from about 5 millimeters to about 8 millimeters, or from about 7 millimeters to about 7.5 millimeters.

The hollow tube-shaped segment may have an internal diameter of approximately 7.1 millimeters.

The ratio between the inner diameter of the hollow tube segment and the outer diameter of the hollow tube segment may be at least approximately 0.8. For example, the ratio between the inner diameter of the hollow tube segment and the outer diameter of the hollow tube segment may be at least approximately 0.85, at least approximately 0.9, or at least approximately 0.95.

The ratio between the inner diameter of the hollow tube segment and the outer diameter of the hollow tube segment may be no more than about 0.99. For example, the ratio between the inner diameter of the hollow tube segment and the outer diameter of the hollow tube segment may be no more than about 0.98.

The ratio between the inner diameter of the hollow tube segment and the outer diameter of the hollow tube segment may be approximately 0.97.

Providing a relatively large inner diameter can advantageously reduce the tightening resistance of the hollow tubular segment.

The lumen of the hollow tubular segment may have any cross-sectional shape. The lumen of the hollow tubular segment may have a circular cross-sectional shape.

The hollow tubular segment may be formed from any material. For example, the hollow tube may comprise cellulose acetate tow. When the hollow tubular segment comprises cellulose acetate tow, the hollow tubular segment may have a thickness of about 0.1 millimeter to about 1 millimeter. The hollow tubular segment may have a thickness of about 0.5 millimeter.

When the hollow tubular segment comprises cellulose acetate tow, the cellulose acetate tow may have a denier per fiber of from about 2 to about 4 and an overall denier of from about 25 to about 40.

The hollow tubular segment may comprise paper. The hollow tubular segment may comprise at least one layer of paper. The paper may be a very rigid paper. The paper may be a corrugated paper, such as a corrugated heat-resistant paper or a corrugated parchment paper. The paper may be cardboard. The hollow tubular segment may be a paper tube. The hollow tubular segment may be formed as a tube of spirally wound paper. The hollow tubular segment may be formed from a plurality of layers of paper. The paper may have a basis weight of at least about 50 grams per square meter, at least about 60 grams per square meter, at least about 70 grams per square meter, or at least about 90 grams per square meter.

When the tubular segment comprises paper, the paper may have a thickness of at least about 50 micrometers. For example, the paper may have a thickness of at least about 70 micrometers, at least about 90 micrometers, or at least about 100 micrometers.

The hollow tubular segment may comprise a polymer. For example, the hollow tubular segment may comprise a polymer film. The polymer film may comprise a cellulose film. The hollow tubular segment may comprise low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers.

The downstream section may comprise a modified tubular element. The modified tubular element may be provided instead of the hollow tubular element. The modified tubular element may be provided immediately downstream of the aerosol-generating substrate. The modified tubular element may abut the aerosol-generating substrate.

The modified tubular element may comprise a tubular main part forming a cavity extending from a first end of the tubular main part located upstream of the flow to a second end of the tubular main part located further downstream. The modified tubular element may also comprise a bent end part forming a first end wall at the first end of the tubular main part located upstream of the flow. The first end wall may define the boundaries of an opening that passes an air flow between the cavity and the outer part of the modified tubular element. Preferably, the opening is designed to provide an air flow from the aerosol-generating substrate through the opening into the cavity.

The cavity of the tubular main part may be substantially empty to provide a substantially unimpeded air flow along the cavity. The RTD of the modified tubular element may be localized in a specific longitudinal position of the modified tubular element. In particular, the RTD of the modified tubular element may be localized on the first end wall. In this way, the RTD of the modified tubular element may be substantially controlled by means of the selected configuration of the first end wall and the opening corresponding thereto. The RTD of the modified tubular element (which is essentially the RTD of the first end wall) is of the same order as the RTD of the hollow tubular segment, as described above.

The modified tubular element may have any length. The modified tubular element may have a length of about 10 millimeters to about 60 millimeters, about 15 millimeters to about 50 millimeters, about 20 millimeters to about 55 millimeters, about 25 millimeters to about 40 millimeters, or about 30 millimeters to about 35 millimeters. For example, the modified tubular element may have a length of about 33 millimeters.

The modified tubular element may have any outer diameter (D _E ). The modified tubular element may have an outer diameter (D _E ) of about 5 millimeters to about 12 millimeters, about 6 millimeters to about 12 millimeters, or about 7 millimeters to about 12 millimeters. The modified tubular element may have an outer diameter (D _E ) of about 7.3 millimeters.

The modified tubular element may have any inner diameter ( _DI ). The modified tubular element may have an inner diameter ( _DI ) of about 2 millimeters to about 10 millimeters, about 4 millimeters to about 9 millimeters, about 5 millimeters to about 8 millimeters, or about 7 millimeters to about 7.5 millimeters. The modified tubular element may have an inner diameter ( _DI ) of about 7.1 millimeters.

The modified tubular element may have a peripheral wall of any thickness. The peripheral wall of the modified tubular element may have a thickness of about 0.05 millimeters to about 0.5 millimeters. The peripheral wall of the modified tubular element may have a thickness of about 0.1 millimeters.

The downstream section may contain ventilation. The ventilation may be provided to allow cooler air from outside the aerosol generating article to enter the interior of the downstream section.

The aerosol generating article may typically have a ventilation level of at least about 10 percent, preferably at least about 20 percent.

In preferred embodiments, the aerosol-generating article has a ventilation level of at least about 20 percent, or 25 percent, or 30 percent. More preferably, the aerosol-generating article has a ventilation level of at least about 35 percent.

The aerosol generating article preferably has a ventilation level of less than about 80 percent. More preferably, the aerosol generating article has a ventilation level of less than about 60 percent or less than about 50 percent.

An aerosol generating product may typically have a ventilation level from approximately 10 percent to approximately 80 percent.

In some embodiments, the aerosol-generating article has a ventilation level of about 20 percent to about 80 percent, preferably about 20 percent to about 60 percent, more preferably about 20 percent to about 50 percent. In other embodiments, the aerosol-generating article has a ventilation level of about 25 percent to about 80 percent, preferably about 25 percent to about 60 percent, more preferably about 25 percent to about 50 percent. In further embodiments, the aerosol-generating article has a ventilation level of about 30 percent to about 80 percent, preferably about 30 percent to about 60 percent, more preferably about 30 percent to about 50 percent.

In particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 40 percent to about 50 percent. In some particularly preferred embodiments, the aerosol-generating article has a ventilation level of about 45 percent.

Without being limited by theory, the present inventors have found that a temperature difference caused by introducing cooler external air into a hollow tubular segment can have a beneficial effect on the nucleation and growth of aerosol particles.

The formation of an aerosol from a gaseous mixture containing various chemical compounds depends on the subtle interactions of nucleation, evaporation and condensation, and droplet coalescence, while taking into account changes in concentration, temperature and vapor velocity fields. The so-called classical nucleation theory is based on the assumption that the fraction of molecules in the gas phase is large enough for them to remain coherent for a long time with a sufficient probability (e.g., with a probability of five tenths). These molecules represent some kind of critical threshold molecular clusters among the transient molecular aggregates, which means that, on average, smaller molecular clusters are more likely to disintegrate sufficiently quickly into the gas phase, whereas larger clusters are, on average, more likely to grow. Such a critical cluster is identified with the key nucleation nucleus from which droplet growth is expected due to condensation of molecules from the vapor. Primary droplets that have just formed are assumed to appear with a certain initial diameter and can then grow by several orders of magnitude. This is facilitated and can be improved by rapidly cooling the surrounding vapor, causing condensation. In this regard, it should be remembered that evaporation and condensation are two sides of the same mechanism, namely mass transfer between a gas and a liquid. Whereas evaporation refers to a net mass transfer from the liquid droplets to the gas phase, condensation is a net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) will cause a decrease in volume (or growth) of the droplets, but will not change the number of droplets.

In this scenario, which may be further complicated by droplet coalescence phenomena, temperature and cooling rate may play an important role in determining the response of the system. In general, different cooling rates may result in significantly different time behavior with respect to liquid phase (droplet) formation, since the nucleation process is typically nonlinear. Without being limited by theory, it is suggested that cooling may cause a rapid decrease in the droplet number concentration, followed by a strong short-term increase in droplet growth (nucleation burst). This nucleation burst may be more significant at lower temperatures. It may also be that higher cooling rates may favor an earlier onset of nucleation. Conversely, a decrease in the cooling rate may have a beneficial effect on the final size that the aerosol droplets eventually reach.

Therefore, the rapid cooling caused by the admission of external air into the hollow tubular segment can be advantageously used to promote the nucleation and growth of aerosol droplets. However, at the same time, the immediate disadvantage of admitting external air into the hollow tubular segment is the dilution of the aerosol stream delivered to the consumer.

The inventors of the present invention have surprisingly found that the dilution effect on the aerosol, which can be measured, in particular the effect on the delivery of the aerosol forming substance (such as glycerol) included in the aerosol generating substrate, is advantageously minimized when the ventilation level is within the ranges described above. In particular, it has been found that ventilation levels from 25 percent to 50 percent, and even more preferably from 28 to 42 percent, lead to particularly satisfactory values of glycerol delivery. At the same time, the duration of nucleation and, therefore, the delivery of nicotine and the aerosol forming substance (such as glycerol) are improved.

Ventilation into the downstream section may be provided along substantially the entire length of the downstream section. When this is the case, the downstream section may comprise a porous material that allows air to enter the downstream section. For example, when the downstream section comprises a hollow tubular segment, the hollow segment may be formed from a porous material that allows air to enter the interior of the hollow tubular segment. When the downstream section comprises a wrapper, the wrapper may be formed from a porous material that allows air to enter the interior of the hollow tubular segment.

The downstream section may comprise a first ventilation zone for providing ventilation to the downstream section. The first ventilation zone comprises a portion of the downstream section through which a greater volume of air can pass compared to the remainder of the downstream section. For example, the first ventilation zone may be a portion of the downstream section with a higher porosity than the remainder of the downstream section.

The first ventilation zone may comprise a porous portion of the downstream section with a ventilation of at least 5 percent. For example, the first ventilation zone may comprise a porous portion of the downstream section with a ventilation of at least 10 percent, at least 20 percent, at least 25 percent, at least 30 percent, or at least 35 percent.

The first ventilation zone may comprise a porous portion of a downstream section with a ventilation of no more than 80 percent. For example, the first ventilation zone may comprise a porous portion of a downstream section with a ventilation of no more than 60 percent or less than 50 percent.

The first ventilation zone may comprise a porous portion of the downstream section with a ventilation of 10 percent to 80 percent, 20 percent to 80 percent, 20 percent to 60 percent, or 20 percent to 50 percent. In other embodiments, the first ventilation zone may comprise a porous portion of the downstream section with a ventilation of 25 percent to 80 percent, 25 percent to 60 percent, or 25 percent to 50 percent. In further embodiments, the first ventilation zone may comprise a porous portion of the downstream section with a ventilation of 30 percent to 80 percent, 30 percent to 60 percent, or 30 percent to 50 percent.

The first ventilation zone may comprise a porous portion of the downstream section with a ventilation of 40 percent to 50 percent. In some particularly preferred embodiments, the first ventilation zone may comprise a porous portion of the downstream section with a ventilation of 45 percent.

The first ventilation zone may comprise a first line of perforations surrounding a downstream section.

In some embodiments, the ventilation zone may comprise two annular rows of perforations. For example, the perforations may be formed on a production line during the manufacturing process of an aerosol-generating article. Each annular row of perforations may comprise from about 5 to about 40 perforations, for example, each annular row of perforations may comprise from about 8 to about 30 perforations.

When the aerosol generating article comprises a unifying wick, the ventilation zone preferably comprises at least one corresponding annular row of perforations provided through a portion of the unifying wick. They can also be formed on a production line during the manufacturing process of the smoking article. Preferably, the annular row or rows of perforations provided through a portion of the unifying wick are substantially in alignment with the row or rows of perforations through a downstream section.

If the aerosol generating article comprises a strip of tipping paper, wherein the strip of tipping paper extends over an annular row or rows of perforations in a downstream section, the ventilation zone preferably comprises at least one corresponding annular row of perforations provided through the strip of tipping paper. They can also be formed on a production line during the manufacturing of the smoking article. Preferably, the annular row or rows of perforations provided through the strip of tipping paper are substantially in alignment with the row or rows of perforations through the downstream section.

The first line of perforations may comprise at least one perforation with a width of at least about 50 micrometers. For example, the first line of perforations may comprise at least one perforation with a width of at least about 65 micrometers, at least about 80 micrometers, at least about 90 micrometers, or at least about 100 micrometers.

The first line of perforations may comprise at least one perforation with a width of no more than about 200 micrometers. For example, the first line of perforations may comprise at least one perforation with a width of no more than about 175 micrometers, no more than about 150 micrometers, no more than about 125 micrometers, or no more than about 120 micrometers.

The first line of perforations may comprise at least one perforation with a width of from about 50 micrometers to about 200 micrometers, from about 65 micrometers to about 175 micrometers, from about 90 micrometers to about 150 micrometers, or from about 100 micrometers to about 120 micrometers.

When perforations are formed using laser perforation techniques, the width of the perforations can be determined by the focal diameter of the laser.

The first line of perforations may comprise at least one perforation with a length of at least approximately 400 micrometers. For example, the first line of perforations may comprise at least one perforation with a length of at least approximately 425 micrometers, at least approximately 450 micrometers, at least approximately 475 micrometers, or at least approximately 500 micrometers.

The first line of perforations may comprise at least one perforation with a length of no more than about 1 millimeter. For example, the first line of perforations may comprise at least one perforation with a length of no more than about 950 micrometers, no more than about 900 micrometers, no more than about 850 micrometers, or no more than about 800 micrometers.

The first line of perforations may comprise at least one perforation with a length of from about 400 micrometers to about 1 millimeter, from about 425 micrometers to about 950 micrometers, from about 450 micrometers to about 900 micrometers, from about 475 micrometers to about 850 micrometers, or from about 500 micrometers to about 800 micrometers.

The first line of perforations may comprise at least one perforation with an opening area of at least about 0.01 square millimeters. For example, the first line of perforations may comprise at least one perforation with an opening area of at least about 0.02 square millimeters, at least about 0.03 square millimeters, or at least about 0.05 square millimeters.

The first line of perforations may comprise at least one perforation with an opening area of no more than about 0.5 square millimeters. For example, the first line of perforations may comprise at least one perforation with an opening area of no more than about 0.3 square millimeters, no more than about 0.25 square millimeters, or no more than about 0.1 square millimeters.

The first line of perforations may comprise at least one perforation with an opening area of about 0.01 square millimeters to about 0.5 square millimeters, about 0.02 square millimeters to about 0.3 square millimeters, about 0.03 square millimeters to about 0.25 square millimeters, or about 0.05 square millimeters to about 0.1 square millimeters. The first line of perforations may comprise at least one perforation with an opening area of about 0.05 square millimeters to about 0.096 square millimeters.

As noted above, the aerosol generating article may comprise a wrapper surrounding at least a portion of the downstream section, the first ventilation zone may comprise a porous portion of the wrapper.

The wrapper may be a paper wrapper and the first ventilation zone may comprise a portion of porous paper.

As indicated above, the downstream section may comprise a hollow tube located at a distance from the downstream end of the aerosol generating substrate. When this is the case, the hollow tube may be connected to the aerosol generating substrate by a paper wrapper. The wrapper may be a porous paper wrapper. When this is the case, the first ventilation zone may comprise a portion of the porous paper wrapper covering the space between the downstream end of the aerosol generating substrate and the upstream end of the hollow tube. In this case, the upstream end of the first ventilation zone abuts the downstream end of the aerosol generating substrate, and the downstream end of the first ventilation zone abuts the upstream end of the hollow tube.

The porous portion of the wrapper that forms the first ventilation zone may have a basis weight that is less than that of the portion of the wrapper that does not form part of the first ventilation zone.

The porous portion of the wrapper that forms the first ventilation zone may have a thickness that is less than that of the portion of the wrapper that does not form part of the first ventilation zone.

The upstream end of the first ventilation zone may be located less than 10 millimeters from the downstream end of the aerosol generating substrate.

For example, the upstream end of the first ventilation zone may be located less than 8 millimeters, less than 5 millimeters, less than 3 millimeters, or less than 1 millimeter from the downstream end of the aerosol generating substrate.

The upstream end of the first ventilation zone may be longitudinally aligned with the downstream end of the aerosol generating substrate.

The upstream end of the first ventilation zone may be located at a distance of less than 25 percent of the path along the length of the downstream element from the downstream end of the aerosol generating substrate. For example, the upstream end of the first ventilation zone may be located at a distance of less than 20 percent, less than 18 percent, less than 15 percent, less than 10 percent, less than 5 percent, or less than 1 percent of the path along the length of the downstream element from the downstream end of the aerosol generating substrate.

The downstream end of the first ventilation zone may be located at a distance of less than 30 percent of the path along the length of the downstream element from the downstream end of the aerosol generating substrate. For example, the downstream end of the first ventilation zone may be located at a distance of less than 25 percent, less than 20 percent, less than 18 percent, less than 15 percent, less than 10 percent, or less than 5 percent of the path along the length of the downstream element from the downstream end of the aerosol generating substrate.

The downstream end of the first ventilation zone may be located no further than 10 millimeters from the downstream end of the aerosol-generating substrate. In other words, the first ventilation zone may be located entirely within 10 millimeters of the aerosol-generating substrate.

For example, the downstream end of the first ventilation zone may be located no further than 8 millimeters, no further than 5 millimeters, or no further than 3 millimeters from the downstream end of the aerosol generating substrate.

The first ventilation zone may be located anywhere along the length of the downstream section. The downstream end of the first ventilation zone may be located no more than about 25 millimeters from the downstream end of the aerosol-generating article. For example, the first ventilation zone may be located no more than about 20 millimeters from the downstream end of the aerosol-generating article.

The arrangement of the first ventilation zone as described above can advantageously prevent the first ventilation zone from being obstructed when the aerosol-generating article is inserted into the aerosol-generating device.

The downstream end of the first ventilation zone may be located at a distance of at least about 8 millimeters from the downstream end of the aerosol-generating article. For example, the downstream end of the first ventilation zone may be located at a distance of at least about 10 millimeters, at least 12 millimeters, or at least about 15 millimeters from the downstream end of the aerosol-generating article.

The arrangement of the first ventilation zone as described above can advantageously prevent the first ventilation zone from being obstructed by the mouth or lips of the user when using the aerosol generating article.

The downstream end of the first ventilation zone may be located at a distance of from about 8 millimeters to about 25 millimeters, from about 10 millimeters to about 25 millimeters, or from about 15 millimeters to about 20 millimeters from the downstream end of the aerosol-generating article. The downstream end of the first ventilation zone may be located at a distance of about 18 millimeters from the downstream end of the aerosol-generating article.

The upstream end of the first ventilation zone may be located at a distance of at least approximately 20 millimeters from the upstream end of the aerosol-generating article. For example, the upstream end of the first ventilation zone may be located at a distance of at least approximately 25 millimeters from the upstream end of the aerosol-generating article.

The arrangement of the first ventilation zone as described above can advantageously prevent the first ventilation zone from being obstructed when the aerosol-generating article is inserted into the aerosol-generating device.

The upstream end of the first ventilation zone may be located at a distance of no more than 37 millimeters from the upstream end of the aerosol-generating article. For example, the upstream end of the first ventilation zone may be located at a distance of no more than approximately 30 millimeters from the upstream end of the aerosol-generating article.

The arrangement of the first ventilation zone as described above can advantageously prevent the first ventilation zone from being obstructed by the mouth or lips of the user when using the aerosol generating article.

The upstream end of the first ventilation zone may be located at a distance of about 20 millimeters to about 37 millimeters or about 25 millimeters to about 30 millimeters from the upstream end of the aerosol-generating article. The upstream end of the first ventilation zone may be located at a distance of about 27 millimeters from the downstream end of the aerosol-generating article.

The first ventilation zone may have any length. The first ventilation zone may have a length of at least 0.5 millimeters. In other words, the longitudinal distance between the downstream end of the first ventilation zone and the upstream end of the first ventilation zone is at least 0.5 millimeters. For example, the first ventilation zone may have a length of at least 1 millimeter, at least 2 millimeters, at least 5 millimeters, or at least 8 millimeters.

The first ventilation zone may have a length of no more than 10 millimeters. For example, the first ventilation zone may have a length of no more than 8 millimeters or no more than 5 millimeters.

The first ventilation zone may have a length of 0.5 millimeters to 10 millimeters. For example, the first ventilation zone may have a length of 1 millimeter to 8 millimeters or 2 millimeters to 5 millimeters.

The aerosol generating article may further comprise an additional element or component in addition to the hollow tubular element and the aerosol generating element, such as a filter segment or a mouthpiece segment. Preferably, a downstream section of the aerosol generating article may comprise an element or component in addition to the hollow tubular element, such as a filter segment or a mouthpiece segment.

Such an additional element may be located downstream of the hollow tubular element. Such an additional element may be located directly downstream of the hollow tubular element. Such an additional element may be located between the aerosol generating element and the hollow tubular element. Such an additional element may extend from the downstream end of the hollow tubular element to the mouth end of the aerosol generating article or to the downstream end of the downstream section. Such an additional element is preferably a downstream element or segment. Such an additional element may be a filter element or segment or a mouth segment. Such an additional element may form part of the downstream section of the aerosol generating article according to the present invention. Such an additional element may be in axial alignment with the remaining components of the aerosol generating article, such as the aerosol generating element and the hollow tubular element. Moreover, the additional element may have a diameter similar to the outer diameter of the hollow tubular element, the diameter of the aerosol generating element, or the diameter of the aerosol generating article.

The aerosol generating article according to the present invention preferably comprises a wrapper surrounding the downstream section (or components of the downstream section). Such a wrapper may be an outer rim wrapper that surrounds the downstream section and a portion of the aerosol generating element, such that the downstream section is attached to the aerosol generating element.

A downstream section of the aerosol generating article of the present invention may form a recessed cavity.

The above-described "additional element" may also be referred to in this specification as a "first section" or "first segment" of the "downstream section". The terms "first segment" or "additional element" may alternatively be referred to in this specification as a "mouthpiece segment", "retaining segment", "downstream segment", "mouthpiece element", "downstream element", "retaining element", "filter element" or "filter segment", or "downstream plug element". The term "mouthpiece" may refer to an element of an aerosol-generating article that is located downstream of an aerosol-generating element of the aerosol-generating article, preferably near the mouth-end of the article.

Unless otherwise specified, the resistance to draw (RTD) of an aerosol-generating component or article is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the entire length of the component. The terms "pressure drop" or "resistance to draw" of a component or article may also refer to "resistance to draw". Such terms generally refer to measurements in accordance with ISO 6565-2015, which are typically performed under test conditions at a volumetric flow rate of approximately 17.5 millilitres per second at the outlet or downstream end of the component being measured, at a temperature of approximately 22 degrees Celsius, a pressure of approximately 101 kPa (approximately 760 Torr) and a relative humidity of approximately 60%.

The resistance to draw per unit length of a specific component (or element) of an aerosol-generating article, such as a downstream section, a first section, or a first segment, can be calculated by dividing the measured resistance to draw of the component by the total axial length of the component. The RTD per unit length refers to the pressure required to force air through a unit length of the component. Throughout this specification, a unit length refers to a length of 1 mm. Accordingly, to obtain the RTD per unit length of a specific component, a sample of a specific length, such as 15 mm, of the component can be used in the measurement. The RTD of such a sample is measured in accordance with ISO 6565-2015. If, for example, the measured RTD is approximately 15 mm H2O, then the RTD per unit length of the component is approximately 1 mm H2O per mm. The RTD per unit length of the component depends on the structural properties of the material used for the component, as well as the geometric shape or cross-sectional profile of the component, among other factors.

The relative RTD, or RTD per unit length, of the downstream section may be from about 0 mmH2O per mm to about 3 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 2.5 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 2 mmH2O per mm. The RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 1 mmH2O per mm. The RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 0.75 mmH2O per mm.

As mentioned above, the relative RTD, or RTD per unit length, of the downstream section may be greater than about 0 mmH2O per mm and less than about 3 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be greater than about 0 mmH2O per mm and less than about 2.5 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be greater than about 0 mmH2O per mm and less than about 2 mmH2O per mm. The RTD per unit length of the downstream section may be greater than about 0 mmH2O per mm and less than about 1 mmH2O per mm. The RTD per unit length of the downstream section may be greater than about 0 mmH2O per mm and less than about 0.75 mmH2O per mm.

The RTD per unit length of the downstream section may be greater than or equal to about 0 mmH2O per mm. Thus, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 3 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 2.5 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 2 mmH2O per mm. The RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 1 mmH2O per mm. The RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 0.75 mmH2O per mm. st. per mm.

The draw resistance of the downstream section may be greater than or equal to about 0 mm H2O and less than about 10 mm H2O. The draw resistance of the downstream section may be greater than 0 mm H2O and less than about 5 mm H2O. The draw resistance of the downstream section may be greater than 0 mm H2O and less than about 2 mm H2O. The draw resistance of the downstream section may be greater than 0 mm H2O and less than about 1 mm H2O.

The upstream end of the aerosol-generating article may be formed by a wrapper. Providing the wrapper at the upstream end of the aerosol-generating article may advantageously retain the aerosol-generating substrate in the aerosol-generating article. This feature may also advantageously prevent users from coming into direct contact with the aerosol-generating substrate.

The wrapper may be mechanically closed at the upstream end of the aerosol-generating article. This may be achieved by folding or twisting the wrapper. An adhesive may be used to close the upstream end of the aerosol-generating article.

The wrapper forming the upstream end of the aerosol generating article may be formed from the same piece of material as the wrapper surrounding at least a portion of the downstream section.

Providing for this may advantageously facilitate the manufacture of the aerosol-generating article, since only one piece of wrapper material may be required. Additionally, the use of one piece of wrapper material may eliminate the need for a seam to join two pieces of wrapper material. This may advantageously facilitate manufacture. The absence of a seam may also advantageously prevent or reduce leakage of any aerosol-generating substrate from the aerosol-generating article.

The aerosol-generating article according to the present invention may further comprise an upstream element upstream of the aerosol-generating substrate. The upstream element may extend from the upstream end of the aerosol-generating substrate to the upstream end of the aerosol-generating article. The upstream element may abut the upstream end of the aerosol-generating article. The upstream element may be referred to as an upstream section.

The aerosol generating article may comprise an air inlet at an upstream end of the aerosol generating article. If the aerosol generating article comprises an upstream element, the air inlet may be provided through the upstream element. Air entering through the air inlet may pass into the aerosol generating substrate to generate a mainstream aerosol.

An upstream section may have a high RTD.

In embodiments of the present invention, if the downstream section has a relatively low RTD, such as an RTD of less than about 10 mm H2O, providing an upstream element having a relatively high RTD can advantageously provide an acceptable overall RTD without the need for a high RTD element, such as a filter, downstream of the aerosol-generating substrate. In use, air enters the aerosol-generating article through the upstream end of the upstream section, passes through the upstream section into the aerosol-generating substrate. The air then passes into and through the downstream section, and then exits from the downstream end of the downstream section.

Most of the total RTD of an aerosol generating product can be provided by the RTD of the upstream section.

The ratio of the RTD of the upstream section to the RTD of the downstream section may be greater than 1. For example, the RTD of the downstream section may be greater than about 2, greater than about 5, greater than about 8, greater than about 10, greater than about 15, greater than about 20, or greater than about 50.

The RTD of the upstream section may be at least about 5 mm H2O. For example, the RTD of the upstream section may be at least about 10 mm H2O, at least about 12 mm H2O, at least about 15 mm H2O, at least about 20 mm H2O.

The RTD of the upstream section may be no more than about 80 mm H2O. For example, the RTD of the upstream section may be no more than about 70 mm H2O, no more than about 60 mm H2O, no more than about 50 mm H2O, or no more than about 40 mm H2O.

The RTD of the upstream section may be from about 5 mmH2O to about 80 mmH2O. For example, the RTD of the upstream section may be from about 10 mmH2O to about 70 mmH2O, from about 12 mmH2O to about 60 mmH2O, from about 15 mmH2O to about 50 mmH2O, or from about 20 mmH2O to about 40 mmH2O.

The upstream section may advantageously prevent direct physical contact with the upstream end of the aerosol-generating substrate. In particular, when the aerosol-generating substrate comprises a susceptor element, the upstream section may prevent direct physical contact with the upstream end of the susceptor element. This helps prevent the susceptor element from shifting or deforming during handling or transport of the aerosol-generating article. This, in turn, helps maintain the shape and position of the susceptor element. In addition, the presence of the upstream section may help prevent any loss of substrate, which may be advantageous, for example, if the substrate comprises particulate plant material.

The upstream section may also provide an improved appearance to the upstream end of the aerosol-generating article. In addition, if desired, the upstream section may be used to provide information about the aerosol-generating article, such as brand, flavor, content, or information about the aerosol-generating device with which the article is intended.

The upstream section may comprise a porous plug element. The porous plug element may have a porosity of at least approximately 50 percent in the longitudinal direction of the aerosol-generating article. More preferably, the porous plug element has a porosity of approximately 50 percent to approximately 90 percent in the longitudinal direction. The porosity of the porous plug element in the longitudinal direction is determined by the ratio of the cross-sectional area of the material forming the porous plug element and the internal cross-sectional area of the aerosol-generating article in the position of the porous plug element.

The porous plug element may be made of a porous material or may comprise a plurality of holes. This may be achieved, for example, by laser perforation. Preferably, the plurality of holes are distributed uniformly over the cross-section of the porous plug element.

The porosity or permeability of the upstream section may be advantageously varied to provide a desired overall draw resistance of the aerosol generating article.

In alternative embodiments, the upstream section may be formed from a material that is impermeable to air. In such embodiments, the aerosol-generating article may be designed so that air flows into the aerosol-generating element through suitable ventilation means provided in the wrapper.

The upstream section may be made of any material suitable for use in an aerosol-generating article. For example, the upstream element may comprise a plug of material. Suitable materials for forming the upstream section include filter materials, ceramics, polymeric material, cellulose acetate, cardboard, zeolite, or an aerosol-generating substrate. Preferably, the upstream section comprises a plug comprising cellulose acetate.

If the upstream section comprises a plug of material, the downstream end of the plug of material may be adjacent to the upstream end of the aerosol generating substrate. For example, the upstream section may comprise a plug comprising cellulose acetate adjacent to the upstream end of the aerosol generating substrate. This may advantageously help to hold the aerosol generating substrate in place.

If the upstream section comprises a plug of material, the downstream end of the plug of material may be spaced from the upstream end of the aerosol generating substrate. The upstream element may comprise a plug comprising fibrous filter material.

Preferably, the upstream section is formed from a heat-resistant material. For example, the upstream section is preferably formed from a material that withstands temperatures of up to 350 degrees Celsius. This ensures that the upstream section is not adversely affected by the heating means for heating the aerosol-generating substrate.

Preferably, the upstream section has a diameter that is approximately equal to the diameter of the aerosol generating article.

The upstream section may have a length of at least about 1 millimeter. For example, the upstream section may have a length of at least about 2 millimeters, at least about 4 millimeters, or at least about 6 millimeters.

The upstream section may have a length of no more than about 15 millimeters. For example, the upstream section may have a length of no more than about 12 millimeters, no more than about 10 millimeters, or no more than about 8 millimeters.

The upstream section may have a length of about 1 millimeter to about 15 millimeters. For example, the upstream section may have a length of about 2 millimeters to about 12 millimeters, about 4 millimeters to about 10 millimeters, or about 6 millimeters to about 8 millimeters.

The length of the upstream section may advantageously vary to provide a desired overall length of the aerosol-generating article. For example, if it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream section may be increased to maintain the same overall length of the article.

The upstream section preferably has a substantially uniform structure. For example, the upstream section may be substantially uniform in texture and appearance. The upstream section may, for example, have a continuous regular surface over the entire cross-section. The upstream section may, for example, have no recognizable symmetries.

The upstream section may comprise a second tubular element. The second tubular element may be provided instead of the upstream element. The second tubular element may be provided immediately upstream of the aerosol-generating substrate. The second tubular element may abut against the aerosol-generating substrate.

The second tubular element may comprise a tubular main part forming a cavity extending from a first end of the tubular main part located upstream of the flow to a second end of the tubular main part located further downstream. The second tubular element may also comprise a bent end part forming a first end wall at the first end of the tubular main part located upstream of the flow. The first end wall may define the boundaries of an opening that allows air flow between the cavity and the outer part of the second tubular element. Preferably, air can pass from the cavity through the opening and into the aerosol-generating substrate.

The second tubular element may comprise a second end wall at the second end of its tubular main part. This second end wall may be formed by bending the end part of the second tubular element at the second downstream end of the tubular main part. The second end wall may define the boundaries of an opening, which may also allow air to flow between the cavity and the outside of the second tubular element. In the case of the second end wall, the opening may be designed such that air can pass from outside the aerosol-generating article through the opening and into the cavity. The opening may therefore provide a channel through which air can be drawn into the aerosol-generating article and through the aerosol-generating substrate.

The upstream section is preferably surrounded by a wrapper. The wrapper surrounding the upstream section is preferably a rigid filament, such as a filament with a basis weight of at least about 80 grams per square meter (g/m2), or at least about 100 g/m2, or at least about 110 g/m2. This provides structural rigidity to the upstream section.

As discussed above, the present invention also relates to an aerosol generating system comprising an aerosol generating device having a distal end and a mouth end. The aerosol generating device comprises a main part. The main part of the aerosol generating device forms a cavity of the device for removably placing an aerosol generating article at the mouth end of the device. The aerosol generating device comprises a heating element or heater for heating an aerosol generating substrate when the aerosol generating article is placed inside the cavity of the device.

The cavity of the device may be called the heating chamber of the aerosol generating device. The cavity of the device may extend between the distal end and the mouthpiece, or near end. The distal end of the cavity of the device may be a closed end, and the mouthpiece, or near end of the cavity of the device may be an open end. The aerosol generating article may be inserted into the cavity of the device, or the heating chamber, through the open end of the cavity of the device. The cavity of the device may have a cylindrical shape in order to match the same shape of the aerosol generating article.

The expression "housed within" may refer to the fact that a component or element is wholly or partially housed within another component or element. For example, the expression "an aerosol-generating article is housed within a cavity of a device" refers to an aerosol-generating article that is wholly or partially housed within a cavity of a device of an aerosol-generating article. When an aerosol-generating article is housed within a cavity of a device, the aerosol-generating article may abut a distal end of the cavity of the device. When an aerosol-generating article is housed within a cavity of a device, the aerosol-generating article may be in substantial proximity to a distal end of the cavity of the device. The distal end of the cavity of the device may be defined by an end wall.

The length of the cavity of the device may be from about 10 mm to about 50 mm. The length of the cavity of the device may be from about 20 mm to about 40 mm. The length of the cavity of the device may be from about 25 mm to about 30 mm. The length of the cavity of the device (or heating chamber) may be the same as or greater than the length of the rod of the substrate forming the aerosol.

The diameter of the cavity of the device may be from about 4 mm to about 50 mm. The diameter of the cavity of the device may be from about 4 mm to about 30 mm. The diameter of the cavity of the device may be from about 5 mm to about 15 mm. The diameter of the cavity of the device may be from about 6 mm to about 12 mm. The diameter of the cavity of the device may be from about 7 mm to about 10 mm. The diameter of the cavity of the device may be from about 7 mm to about 8 mm.

The diameter of the cavity of the device may be the same as or larger than the diameter of the aerosol-generating article. The diameter of the cavity of the device may be the same as the diameter of the aerosol-generating article to form an interference fit with the aerosol-generating article.

The cavity of the device may be designed to form a press fit with an aerosol-generating article located inside the cavity of the device. The press fit may refer to a tight fit. The aerosol-generating device may comprise a peripheral wall. Such a peripheral wall may form a cavity of the device, or a heating chamber. The peripheral wall forming the cavity of the device may be designed to engage with the aerosol-generating article located inside the cavity of the device by means of a press fit, so that there is essentially no gap or empty space between the peripheral wall forming the cavity of the device and the aerosol-generating article when it is located inside the device.

Such an interference fit may form an airtight fit or configuration between the cavity of the device and the aerosol generating article located therein.

With such an air-tight configuration, there will be essentially no gap or empty space between the peripheral wall forming the cavity of the device and the aerosol generating article for air to flow therethrough.

An interference fit with the aerosol generating article may be formed along the entire length of the cavity of the device or along a portion of the length of the cavity of the device.

The aerosol generating device may comprise an air flow channel extending between the channel inlet and the channel outlet. The air flow channel may be configured to create a fluid communication between the interior of the cavity of the device and the exterior of the aerosol generating device. The air flow channel of the aerosol generating device may be formed inside the casing of the aerosol generating device to provide a fluid communication between the interior of the cavity of the device and the exterior of the aerosol generating device. When the aerosol generating article is placed inside the cavity of the device, the air flow channel may be configured to provide an air flow into the article to deliver the generated aerosol to the user who puffs through the mouth end of the article.

The air flow channel of the aerosol generating device may be formed inside the peripheral wall of the casing of the aerosol generating device, or by this peripheral wall. In other words, the air flow channel of the aerosol generating device may be formed within the thickness of the peripheral wall, or by the inner surface of the peripheral wall, or by a combination of both. The air flow channel may be partially formed by the inner surface of the peripheral wall and may be partially formed within the thickness of the peripheral wall. The inner surface of the peripheral wall defines a peripheral boundary of the cavity of the device.

The air flow channel of the aerosol generating device may extend from an inlet located at the mouth end, or proximal end, of the aerosol generating device to an outlet located at a distance from the mouth end of the device. The air flow channel may extend along a direction parallel to the longitudinal axis of the aerosol generating device.

The aerosol generating device may comprise an elongated heater (or heating element) designed to be inserted into the aerosol generating article when the aerosol generating article is positioned within the cavity of the device. The elongated heater may be arranged with the cavity of the device. The elongated heater may extend into the cavity of the device. Alternative arrangements for heating will be discussed in more detail below.

The heater may be any suitable type of heater. Preferably, the heater is an external heater.

Preferably, the heater can externally heat the aerosol-generating article when it is placed inside the aerosol-generating device. Such an external heater can surround the aerosol-generating article when it is inserted into the aerosol-generating device or placed inside it.

In some embodiments, the heater is arranged to heat the outer surface of the aerosol-forming substrate. In some embodiments, the heater is adapted to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is positioned within the cavity. The heater may be located within the cavity of the device, or a heating chamber.

The heater may comprise at least one heating element. The at least one heating element may be a heating element of any suitable type. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises a plurality of heating elements. The heater may comprise at least one resistive heating element. Preferably, the heater comprises a plurality of resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing a plurality of resistive heating elements electrically connected in a parallel arrangement may facilitate the delivery of the desired electrical power to the heater, while reducing or minimizing the voltage required to provide the desired electrical power. Advantageously, reducing or minimizing the voltage required to operate the heater may contribute to reducing or minimizing the physical size of the power supply.

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

In some embodiments, at least one resistive heating element comprises one or more stamped portions of an electrically resistive material, such as stainless steel. Alternatively, at least one resistive heating element may comprise a heating wire or filament, such as a Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire.

In some embodiments, at least one heating element comprises an electrically insulating substrate, wherein at least one resistive heating element is provided on the electrically insulating substrate.

The electrically insulating substrate may comprise any suitable material. For example, the electrically insulating substrate may comprise one or more of paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic may comprise mica, aluminum oxide (Al ₂ O ₃ ), or zirconium dioxide (ZrO ₂ ). Preferably, the electrically insulating substrate has a thermal conductivity that is less than or equal to about 40 watts per meter Kelvin, preferably less than or equal to about 20 watts per meter Kelvin, and ideally less than or equal to about 2 watts per meter Kelvin.

The heater may comprise a heating element comprising a rigid electrically insulating substrate with one or more electrically conductive paths or wires located on its surface. The size and shape of the electrically insulating substrate may allow it to be inserted directly into the aerosol-forming substrate. If the electrically insulating substrate is not rigid enough, the heating element may comprise additional means for imparting rigidity. Current may pass through one or more electrically conductive paths to heat the heating element and the aerosol-forming substrate.

In some embodiments, the heater comprises an induction heating device. The induction heating device may comprise an induction coil and a power supply configured to provide a high-frequency oscillating current to the induction coil. In the context of this document, "high-frequency oscillating current" means an oscillating current with a frequency of 500 kHz to 30 MHz. The heater may advantageously comprise a DC-AC converter for converting a DC current supplied by a DC power supply into an AC current. The induction coil may be designed to generate a high-frequency oscillating electromagnetic field when receiving the high-frequency oscillating current from the power supply. The induction coil may be designed to generate a high-frequency oscillating electromagnetic field in a cavity of the device. In some embodiments, the induction coil may substantially surround the cavity of the device. The induction coil may extend at least partially along the length of the cavity of the device.

The heater may comprise an induction heating element. The induction heating element may be a current collector. In the context of this document, the term "current collector" refers to an element comprising a material that is capable of converting electromagnetic energy into heat. When the current collector is placed in an alternating electromagnetic field, the current collector heats up. The heating of the current collector may be the result of at least one of hysteresis losses and eddy currents induced in the current collector, depending on the electrical and magnetic properties of the current collector material.

The current-receiving element can be arranged so that when the aerosol-generating article is placed in the cavity of the aerosol-generating device, the oscillating electromagnetic field generated by the induction coil induces a current in the current-receiving element, which leads to heating of the current-receiving element. In these embodiments, the aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (field strength H) of 1 to 5 kiloamperes per meter (kA/m), preferably 2 to 3 kA/m, such as approximately 2.5 kA/m. The electrical aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a frequency of 1 to 30 MHz, such as 1 to 10 MHz, such as 5 to 7 MHz.

In some embodiments, the current collecting element is located in the aerosol-generating article. In these embodiments, the current collecting element is preferably located in contact with the aerosol-forming substrate. The current collecting element can be located in the aerosol-forming substrate.

In some embodiments, the current-collecting element is located in the aerosol-generating device. In these embodiments, the current-collecting element may be located in the cavity. The aerosol-generating device may contain only one current-collecting element. The aerosol-generating device may contain a plurality of current-collecting elements.

In some embodiments, the current collecting element is arranged to heat the outer surface of the aerosol-forming substrate. In some embodiments, the current collecting element is adapted to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is located within the cavity.

The current collecting element may comprise any suitable material. The current collecting element may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-forming substrate. Suitable materials for the elongated current collecting element include graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminum, nickel, nickel compounds, titanium, and composites of metallic materials. Some current collecting elements comprise metal or carbon. Advantageously, the current collecting element may comprise or consist of a ferromagnetic material, such as ferritic iron, a ferromagnetic alloy such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A suitable current collecting element may be made of or comprise aluminum. The current collecting element preferably comprises more than about 5 percent, preferably more than about 20 percent, more preferably more than about 50 percent or more than about 90 percent of ferromagnetic or paramagnetic materials. Some elongated current collecting elements can be heated to a temperature in excess of about 250 degrees Celsius.

The current collecting element may comprise a non-metallic core with a metallic layer located on the non-metallic core. For example, the current collecting element may comprise metallic tracks formed on the outer surface of a ceramic core or substrate.

In some embodiments, the aerosol generating device may comprise at least one resistive heating element and at least one inductive heating element. In some embodiments, the aerosol generating device may comprise a combination of resistive heating elements and inductive heating elements.

During use, the heater can be controlled to operate in a certain range of operating temperatures below the maximum operating temperature. The operating temperature range is preferably from about 150 degrees Celsius to about 300 degrees Celsius in the heating chamber (or cavity of the device). The operating temperature range of the heater can be from about 150 degrees Celsius to about 250 degrees Celsius.

Preferably, the operating temperature range of the heater may be from about 150 degrees Celsius to about 200 degrees Celsius. More preferably, the operating temperature range of the heater may be from about 180 degrees Celsius to about 200 degrees Celsius. In particular, it has been found that optimal and stable aerosol delivery can be achieved by using an aerosol generating device having an external heater that has an operating temperature range of from about 180 degrees Celsius to about 200 degrees Celsius, wherein the aerosol generating articles have a relatively low RTD (e.g., less than 10 mm H2O), as described throughout this specification.

In embodiments where the aerosol generating article comprises a ventilation zone at a location along a downstream section or hollow tubular element, the ventilation zone may be positioned to be open when the aerosol generating article is positioned within the cavity of the device.

The aerosol generating device may comprise a power supply. The power supply may be a DC power supply. In some embodiments, the power supply is a battery. The power supply may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery, such as a lithium-cobalt, lithium-iron phosphate, or lithium-polymer battery. However, in some embodiments, the power supply may be another type of charge storage device, such as a capacitor. The power supply may require recharging and may have a capacity that allows storing enough energy for one or more user operations, such as one or more aerosol generation sessions. For example, the power supply may have sufficient capacity to ensure continuous heating of the aerosol-forming substrate for a period of approximately six minutes, which corresponds to the typical time required to smoke a conventional cigarette, or for a period that is a multiple of six minutes. In another example, the power supply may have sufficient capacity to enable a specified number of puffs or individual heater activations.

The aerosol generating article may have a length from approximately 35 millimeters to approximately 100 millimeters.

Preferably, the total length of the aerosol-generating article according to the present invention is at least about 38 millimeters. More preferably, the total length of the aerosol-generating article according to the present invention is at least about 40 millimeters. Even more preferably, the total length of the aerosol-generating article according to the present invention is at least about 42 millimeters.

The total length of the aerosol-generating article according to the present invention is preferably less than or equal to 70 millimeters. More preferably, the total length of the aerosol-generating article according to the present invention is preferably less than or equal to 60 millimeters. Even more preferably, the total length of the aerosol-generating article according to the present invention is preferably less than or equal to 50 millimeters.

In some embodiments, the overall length of the aerosol-generating article is preferably from about 38 millimeters to about 70 millimeters, more preferably from about 40 millimeters to about 70 millimeters, even more preferably from about 42 millimeters to about 70 millimeters. In other embodiments, the overall length of the aerosol-generating article is preferably from about 38 millimeters to about 60 millimeters, more preferably from about 40 millimeters to about 60 millimeters, even more preferably from about 42 millimeters to about 60 millimeters. In further embodiments, the overall length of the aerosol-generating article is preferably from about 38 millimeters to about 50 millimeters, more preferably from about 40 millimeters to about 50 millimeters, even more preferably from about 42 millimeters to about 50 millimeters. In an exemplary embodiment, the overall length of the aerosol generating article is approximately 45 millimeters.

The aerosol generating article has an external diameter of at least 5 millimeters. Preferably, the aerosol generating article has an external diameter of at least 6 millimeters. More preferably, the aerosol generating article has an external diameter of at least 7 millimeters.

Preferably, the aerosol-generating article has an outer diameter that is less than or equal to approximately 12 millimeters. More preferably, the aerosol-generating article has an outer diameter that is less than or equal to approximately 10 millimeters. Even more preferably, the aerosol-generating article has an outer diameter that is less than or equal to approximately 8 millimeters.

In some embodiments, the aerosol-generating article has an outer diameter of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 12 millimeters, more preferably about 7 millimeters to about 12 millimeters. In other embodiments, the aerosol-generating article has an outer diameter of about 5 millimeters to about 10 millimeters, preferably about 6 millimeters to about 10 millimeters, more preferably about 7 millimeters to about 10 millimeters. In further embodiments, the aerosol-generating article has an outer diameter of about 5 millimeters to about 8 millimeters, preferably about 6 millimeters to about 8 millimeters, more preferably about 7 millimeters to about 8 millimeters.

One or more components of the aerosol-generating article may be individually surrounded by a wrapper. In preferred embodiments, all components of the aerosol-generating article are individually surrounded by their own wrapper. Preferably, at least one of the components of the aerosol-generating article is wrapped in a hydrophobic wrapper.

The term "hydrophobic" refers to a surface that exhibits water-repellent properties. One commonly used method for determining this property is by measuring the water contact angle. The "water contact angle" is the angle, typically measured by a liquid, where the liquid/vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid according to Young's equation. Hydrophobicity or water contact angle can be determined using TAPPI Test Method T558 and the result is reported as the contact angle at the interface, expressed in "degrees", which can range from approximately zero to approximately 180 degrees.

In preferred embodiments, the hydrophobic wrapper is a wrapper comprising a paper layer having a water contact angle of about 30 degrees or greater, and preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

As an example, the paper layer may contain PVOH (polyvinyl alcohol) or silicon. PVOH may be applied to the paper layer as a surface coating, or the paper layer may have a surface treatment that includes PVOH or silicon.

In a particularly preferred embodiment, the aerosol generating article according to the present invention comprises, in a linear sequential arrangement, an aerosol generating element comprising a rod comprising an aerosol generating substrate and a hollow tubular element positioned immediately downstream of the aerosol generating element.

In more detail, the hollow tubular element may abut against the aerosol generating element.

The aerosol generating article has a substantially cylindrical shape and an outer diameter of approximately 7.3 millimeters.

The hollow tubular element has the form of a hollow cellulose acetate tube and has an internal diameter of approximately 7.1 millimeters. Thus, the thickness of the peripheral wall of the hollow tubular element is approximately 0.1 millimeters. The ventilation zone is provided at a location along the hollow tubular element.

The aerosol generating element has the form of a rod of aerosol generating substrate surrounded by a paper wrapper and comprises at least one of the types of aerosol generating substrate described above, such as a plant cut filler, and in particular a tobacco cut filler, homogenized tobacco, a gel composition or a homogenized plant material containing particles of a plant other than tobacco.

An outer rim wrapper surrounds the hollow tubular member and a portion of the aerosol generating member such that the hollow tubular member is secured to the aerosol generating member.

The aerosol generating substrate rod is approximately 12 millimeters long, the hollow tubular element is approximately 33 millimeters long. Thus, the total length of the aerosol generating article is approximately 45 millimeters.

In another preferred embodiment, an aerosol generating article according to the present invention comprises, in a linear sequential arrangement, an upstream element, an aerosol generating element positioned immediately downstream of the upstream element, an aerosol generating element comprising a rod comprising an aerosol generating substrate, and a hollow tubular element positioned immediately downstream of the aerosol generating element.

In more detail, the rod of the aerosol-generating substrate may abut against an upstream element. In addition, the hollow tubular element may abut against the aerosol-generating element.

The aerosol generating article has a substantially cylindrical shape and an outer diameter of approximately 7.3 millimeters.

The hollow tubular element has the form of a hollow cellulose acetate tube and has an internal diameter of approximately 7.1 millimeters. Thus, the thickness of the peripheral wall of the hollow tubular element is approximately 0.1 millimeters. The ventilation zone is provided at a location along the hollow tubular element.

The aerosol generating element has the form of a rod of aerosol generating substrate surrounded by a paper wrapper and comprises at least one of the types of aerosol generating substrate described above, such as a plant cut filler, and in particular a tobacco cut filler, homogenized tobacco, a gel composition or a homogenized plant material containing particles of a plant other than tobacco.

An outer rim wrapper surrounds the hollow tubular member and a portion of the aerosol generating member such that the hollow tubular member is secured to the aerosol generating member.

The upstream element is 5 millimeters long, the aerosol-generating substrate rod is approximately 12 millimeters long, and the hollow tubular element is approximately 28 millimeters long. The total length of the aerosol-generating article is therefore approximately 45 millimeters.

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

Example 1. An aerosol generating article for producing an inhalable aerosol upon heating, wherein the aerosol generating article extends from a mouthpiece end to a distal end and comprises:

an aerosol generating element comprising an aerosol generating substrate, wherein the aerosol generating substrate comprises a substance for forming an aerosol;

a downstream section at a location downstream of the aerosol generating element, the downstream section extending from a downstream end of the aerosol generating element to a mouthpiece end of the aerosol generating article;

wherein the section located further downstream contains a hollow tubular element;

wherein the ratio of the length to the diameter of the aerosol generating element is from about 0.5 to about 3.0; and

wherein the aerosol generating substrate comprises tobacco cut filler, and the content of the aerosol forming substance in the aerosol generating substrate is at least about 8 percent by weight.

Example 2. An aerosol generating article according to example 1, wherein the length to diameter ratio of the aerosol generating element is from approximately 1.3 to approximately 1.9.

Example 3. An aerosol generating article according to example 1 or 2, wherein the aerosol generating element has a length of from about 10 millimeters to about 35 millimeters.

Example 4. An aerosol generating article according to any of examples 1-3, wherein the aerosol generating element has a diameter of from about 6 millimeters to about 7.5 millimeters.

Example 5. An aerosol generating article according to any of the previous examples, wherein the packing density of the tobacco cut filler in the aerosol generating element is at least approximately 100 milligrams/cubic centimeter.

Example 6. An aerosol generating article according to any of the previous examples, wherein the tobacco cut filler comprises at least about 25 percent by weight of tobacco leaf slices.

Example 7. An aerosol generating article according to any of the previous examples, wherein the tobacco cut filler comprises particles having a cut width from about 0.3 millimeters to about 2.0 millimeters.

Example 8. An aerosol generating article according to any of the previous examples, wherein the weight of the tobacco cut filler in the aerosol generating element is at least approximately 100 milligrams.

Example 9. An aerosol-generating article according to any of the previous examples, wherein the content of the aerosol-forming substance in the aerosol-generating substrate is at least about 10 percent by weight.

Example 10. An aerosol generating article according to any of the previous examples, wherein the downstream section comprises a ventilation zone at a location along the hollow tubular element.

Example 11. An aerosol generating article according to example 10, wherein the aerosol generating article has a ventilation level of at least about 10 percent.

Example 12. An aerosol generating article according to example 10 or 11, wherein the distance between the ventilation zone and the mouthpiece end of the aerosol generating article is less than approximately 20 millimetres.

Example 13. An aerosol generating article according to any of the previous examples, wherein the hollow tubular element has a length of at least approximately 10 millimeters, and the cross-section of the hollow tubular element is substantially constant.

Example 14. An aerosol generating article according to any of examples 1-13, wherein the hollow tubular element extends the entire distance to the mouth end of the aerosol generating article.

Example 15. An aerosol generating article according to any one of examples 1-13, wherein the downstream section has an RTD of less than about 50 millimeters of water.

The present invention will now be further described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic side sectional view of an aerosol generating article according to an embodiment of the present invention;

Fig. 2 is a schematic side sectional view of another aerosol generating article in accordance with another embodiment of the present invention;

Fig. 3 shows a schematic side sectional view of a variant of the aerosol generating article according to Fig. 1; and

Fig. 4 shows a schematic side view in section of the embodiment of the aerosol generating article according to Fig. 2.

The aerosol generating article 10 shown in Fig. 1 comprises a rod 12 of an aerosol generating substrate 12 and a downstream section 14 at a location downstream of the rod 12 of the aerosol generating substrate. Thus, the aerosol generating article 10 extends from an upstream or distal end 16, which substantially coincides with the upstream end of the rod 12, to a downstream or mouth end 18, which coincides with the downstream end of the downstream section 14.

The aerosol generating article 10 has a total length of approximately 45 millimeters.

The rod of the aerosol-generating substrate 12 contains tobacco cut filler impregnated with approximately 12 percent by weight of an aerosol-forming substance, such as glycerin. The tobacco cut filler contains 90 percent by weight of tobacco leaf lamellas. The cutting width of the tobacco cut filler is approximately 0.7 millimeters. The rod of the aerosol-generating substrate 12 contains approximately 130 milligrams of tobacco cut filler.

The downstream section 14 comprises a hollow tubular element 20 positioned immediately downstream of the aerosol-generating substrate rod 12, wherein the hollow tubular element 20 is in longitudinal alignment with the rod 12. In the embodiment of Fig. 1, the upstream end of the hollow tubular element 20 abuts the downstream end of the aerosol-generating substrate rod 12.

The hollow tubular member 20 forms a hollow section of the aerosol generating article 10. The hollow tubular member does not substantially affect the overall RTD of the aerosol generating article. In more detail, the RTD of the downstream section is approximately 0 mm H2O.

The hollow tubular element 20 is provided in the form of a hollow cylindrical tube made of cellulose acetate or of rigid paper, such as paper having a square meter weight of at least approximately 90 grams per square meter. The hollow tubular element 20 forms an internal cavity 22 that extends all the way from the upstream end 24 of the hollow tubular segment to the downstream end 26 of the hollow tubular element 20. The internal cavity 22 is substantially empty, and therefore a substantially unimpeded air flow through the internal cavity 22 is possible. The hollow tubular element 20 does not substantially affect the overall RTD of the aerosol-generating article 10.

The hollow tubular element 20 has a length of approximately 33 millimeters, an outer diameter (D _E ) of approximately 7.3 millimeters, and an inner diameter (D _I ) of approximately 7.1 millimeters. Thus, the thickness of the peripheral wall of the hollow tubular element 20 is approximately 0.1 millimeters.

The aerosol generating article 10 comprises a ventilation zone 30 provided at a location along the hollow tubular element 20. In more detail, the ventilation zone 30 is provided at a distance of approximately 18 millimeters from the downstream end 26 of the hollow tubular element 20. As such, in the embodiment of Fig. 1, the ventilation zone 30 is actually provided at a distance of 18 millimeters from the mouth end 18 of the aerosol generating article 10. The ventilation level of the aerosol generating article 10 is approximately 40 percent.

In the embodiment of Fig. 1, the aerosol generating article does not contain any additional component upstream of the aerosol generating substrate rod 12 or downstream of the hollow tubular segment 20.

The aerosol generating article 100 shown in Fig. 2 differs from the aerosol generating article 10 described above only by providing an upstream section at a location upstream of the aerosol generating element. Accordingly, the aerosol generating article 100 will be described below only with respect to its differences from the aerosol generating article 10.

Above the rod 12 of the aerosol generating substrate and the downstream section 14 at a location downstream of the rod 12, the aerosol generating article 100 comprises an upstream section 40 at a location upstream of the rod 12. Thus, the aerosol generating article 10 extends from a distal end 16 substantially coinciding with the upstream end of the upstream section 40 to a mouth end, or downstream end, 18 substantially coinciding with the downstream end of the downstream section 14.

The upstream section 40 comprises an upstream element 42 positioned immediately upstream of the aerosol generating substrate rod 12, wherein the upstream element 42 is in longitudinal alignment with the rod 12. In the embodiment of Fig. 2, the downstream end of the upstream element 42 abuts the upstream end of the aerosol generating substrate rod 12. The upstream element 42 is provided in the form of a cylindrical plug made of cellulose acetate surrounded by a rigid wrapper. The upstream element 42 has a length of approximately 5 millimeters. The RTD of the upstream element 42 is approximately 30 millimeters of water.

Fig. 3 shows an aerosol generating article 200, which is a variant of the aerosol generating article 10 described above. The aerosol generating article 200 is generally the same as the aerosol generating article 10 according to the embodiment of Fig. 1, except that the aerosol generating article 200 according to the variant of the first embodiment does not include the cylindrical hollow tubular element 22, which is described above. Instead, the aerosol generating article 200 according to the variant according to the first embodiment includes a modified tubular element 220, located immediately downstream of the aerosol generating element 12.

The modified tubular element 220 comprises a tubular main part 222 defining a cavity 224 extending from a first end of the tubular main part 222 to a second end of the tubular main part 222. The modified tubular element 220 also comprises a bent end part defining a first end wall 226 at the first end of the tubular main part 222. The first end wall 226 defines the boundaries of an opening 228 that provides air flow between the cavity 224 and the outer part of the modified tubular element 220. In particular, the embodiment of Fig. 3 is designed so that the aerosol can flow from the aerosol generating element 12 through the opening 228 into the cavity 224.

Like the cavity 22 according to the first embodiment shown in Fig. 1, the cavity 224 of the tubular main part 222 is substantially empty, and therefore a substantially unimpeded air flow is provided through the cavity 222. Therefore, the RTD of the modified tubular element 220 can be localized in a specific longitudinal position of the modified tubular element 220, namely on the first end wall 226, and it can be controlled by means of the selected configuration of the first end wall 226 and its corresponding opening 228.

In the embodiment of Fig. 3, the modified tubular element 220 has a length of approximately 33 millimeters, an outer diameter (D _E ) of approximately 7.3 millimeters, and an inner diameter (D _FTS ) of approximately 7.1 millimeters. Thus, the thickness of the peripheral wall of the tubular main part 222 is approximately 0.1 millimeters.

Fig. 4 shows an aerosol generating article 300, which is a variant of the aerosol generating article 100 described above. The aerosol generating article 300 is generally the same as the aerosol generating article 100 according to the embodiment of Fig. 2, except that the aerosol generating article 300 according to the variant according to the second embodiment does not include an upstream element 42 provided in the form of a cylindrical plug made of cellulose acetate surrounded by a rigid wrapper. Instead, the aerosol generating article 300 according to the variant according to the second embodiment includes a second tubular element 44 located immediately upstream of the aerosol generating element 12. Therefore, in this embodiment according to the second embodiment, the hollow tubular element 20 located immediately downstream of the aerosol generating element 12 may be referred to as the first tubular element 20.

The second tubular element 44 comprises a tubular main part 46, forming a cavity 48, extending from the first end of the tubular main part 46 to the second end of the tubular main part 46. The second tubular element 44 also comprises a bent end part, forming a first end wall 50 at the first end of the tubular main part 46. The first end wall 50 defines the boundaries of an opening 52, which provides air flow between the cavity 48 and the outer part of the second tubular element 44. In particular, the embodiment of Fig. 4 is designed so that air can flow from the cavity 48 through the opening 52 into the element 12, generating an aerosol.

In addition, the second tubular element 44 comprises a second end wall 54 at the second end of its tubular main part 46. This second end wall 54 is formed by bending the end part of the second tubular element 44 at the second end of the tubular main part 46. The second end wall 54 defines the boundaries of an opening 56, which also provides an air flow between the cavity 48 and the outer part of the second tubular element 44. In the case of the second end wall 54, the opening 56 is designed so that air can flow from the outer part of the aerosol-generating article 300 through the opening 56 into the cavity 48. Accordingly, the opening 56 provides a channel through which air can be drawn into the aerosol-generating article 300 through the aerosol-generating element 12.

In the embodiment according to Fig. 4, the end of the second tubular element 44 located further downstream of the flow rests against the end of the rod 12 of the aerosol-generating substrate located upstream of the flow. The second tubular element 44 has a length of approximately 5 millimeters.

Claims (12)

1. An aerosol-generating article for producing an inhalable aerosol upon heating, wherein the aerosol-generating article extends from a mouthpiece end to a distal end and comprises: an aerosol-generating element having a diameter of from 6 to 7.5 mm and comprising an aerosol-generating substrate, wherein the aerosol-generating substrate comprises an aerosol-forming substance; and a downstream section at a location downstream of the aerosol-generating element, wherein the downstream section extends from a downstream end of the aerosol-generating element to the mouthpiece end of the aerosol-generating article, wherein the downstream section comprises a hollow tubular element and a ventilation zone at a location along the hollow tubular element, wherein the aerosol-generating article has a ventilation level of at least 10%; wherein the ratio of the length to the diameter of the aerosol generating element is from 0.5 to 2.75; wherein the aerosol generating substrate comprises cut tobacco filler, wherein the content of the aerosol forming substance in the aerosol generating substrate is at least 8% by weight. 2. An aerosol generating article according to claim 1, wherein the ratio of the length to the diameter of the aerosol generating element is from 1.3 to 1.9. 3. An aerosol generating article according to claim 1 or 2, wherein the aerosol generating element has a length of 10 to 35 mm. 4. An aerosol generating article according to any of the preceding claims, wherein the packing density of the tobacco cut filler in the aerosol generating element is at least 100 mg/ ^cm3 . 5. An aerosol generating article according to any one of the preceding claims, wherein the tobacco cut filler comprises at least 25% by weight of tobacco leaf slices. 6. An aerosol generating article according to any of the preceding claims, wherein the tobacco cut filler comprises particles having a cut width of from 0.3 to 2.0 mm. 7. An aerosol generating article according to any of the preceding claims, wherein the weight of the tobacco cut filler in the aerosol generating element is at least 100 mg. 8. An aerosol-generating article according to any of the preceding claims, wherein the content of the aerosol-forming substance in the aerosol-generating substrate is at least 10% by weight. 9. An aerosol generating article according to any of the preceding claims, wherein the distance between the ventilation zone and the mouth end of the aerosol generating article is less than 20 mm. 10. An aerosol generating article according to any of the preceding claims, wherein the hollow tubular element has a length of at least 10 mm and the cross-section of the hollow tubular element is constant. 11. An aerosol generating article according to any one of claims 1 to 10, wherein the hollow tubular element extends the entire distance to the mouth end of the aerosol generating article. 12. An aerosol generating article according to any one of claims 1 to 11, wherein the downstream section has an RTD of less than 50 mm H2O.