EP4210516A1

EP4210516A1 - An aerosol generating article and an aerosol generating system

Info

Publication number: EP4210516A1
Application number: EP21773499.5A
Authority: EP
Inventors: Alec WRIGHT; Andrew Robert John ROGAN
Original assignee: JT International SA
Current assignee: JT International SA
Priority date: 2020-09-07
Filing date: 2021-09-03
Publication date: 2023-07-19
Also published as: WO2022049247A1; JP2023540937A

Abstract

An aerosol generating article (10, 70, 80) is configured for use with an electrically- operated aerosol generating device (30, 60) having a heater (58). The aerosol generating article (10, 70, 80) has a distal end (12) and a mouth end (14) downstream of the distal end (12). The aerosol generating article (10, 70, 80) comprises an aerosol generating substrate (16) and a wrapper (22) which circumscribes the aerosol generating substrate (16) and extends between the distal end (12) and the mouth end (14) to form a rod. The aerosol generating article (10, 70, 80) has an air inlet (24) at the distal end (12) and an air outlet (26) at the mouth end (14) and includes a self-sealing airflow barrier (28) which prevents airflow from the air inlet (24) to the air outlet (26). The self-sealing airflow barrier (28) is breachable, e.g., by an insertion element 52, upon insertion of at least the distal end (12) of the aerosol generating article (10, 70, 80) into an aerosol generating device (30, 60) to permit airflow from the air inlet (24) to the air outlet (26), and is capable of self-sealing (i.e. resealing) upon removal of the insertion element (52).

Description

AN AEROSOL GENERATING ARTICLE AND AN AEROSOL GENERATING SYSTEM

Technical Field

The present disclosure relates generally to aerosol generating articles, and more particularly to an aerosol generating article for use with an aerosol generating device for heating the aerosol generating article to generate an aerosol for inhalation by a user. Embodiments of the present disclosure also relate to an aerosol generating system comprising an aerosol generating device and an aerosol generating article. The present disclosure is particularly applicable to aerosol generating articles for use with a portable (hand-held) aerosol generating device.

Technical Background

The popularity and use of reduced-risk or modified-risk devices (also known as aerosol generating devices or vapour generating devices) has grown rapidly in recent years as an alternative to the use of traditional tobacco products. Various devices and systems are available that heat or warm aerosol generating substances to generate an aerosol for inhalation by a user.

A commonly available reduced-risk or modified-risk device is the heated substrate aerosol generating device, or so-called heat-not-bum device. Devices of this type generate an aerosol or vapour by heating an aerosol generating substrate to a temperature typically in the range 150°C to 300°C. Heating the aerosol generating substrate to a temperature within this range, without burning or combusting the aerosol generating substrate, generates a vapour which typically cools and condenses to form an aerosol for inhalation by a user of the device.

Currently available aerosol generating devices can use one of a number of different approaches to provide heat to the aerosol generating substrate, including resistive heating and induction heating. Whichever approach is used to heat the aerosol generating substrate, it can be convenient to provide the aerosol generating substrate in the form of an aerosol generating article that is configured for use with an aerosol generating device. Aerosol generating articles are known in the art and typically comprise an aerosol generating substrate positioned at a distal end of the aerosol generating article and a filter positioned at the proximal (mouth) end.

It is conceivable that a user may inadvertently attempt to ignite the aerosol generating article in a conventional manner, using a flame or other ignition source. There is, therefore, a need to provide an aerosol generating article, for use with an aerosol generating device, which has a reduced susceptibility to ignition using a flame or other ignition source.

Summary of the Disclosure

According to a first aspect of the present disclosure, there is provided an aerosol generating article having a distal end and a mouth end downstream of the distal end, the aerosol generating article comprising: an aerosol generating substrate; a wrapper which circumscribes the aerosol generating substrate and extends between the distal end and the mouth end to form a rod; an air inlet at the distal end and an air outlet at the mouth end; and a self-sealing airflow barrier which prevents airflow from the air inlet to the air outlet, the self-sealing airflow barrier being breachable upon insertion of at least the distal end of the aerosol generating article into an aerosol generating device to permit airflow from the air inlet to the air outlet.

According to a specific embodiment of the first aspect, there is provided an aerosol generating article having a distal end and a mouth end downstream of the distal end, the aerosol generating article comprising: an aerosol generating substrate; a wrapper which circumscribes the aerosol generating substrate and extends between the distal end and the mouth end to form a rod; an air inlet at the distal end and an air outlet at the mouth end; and a self-sealing airflow barrier at the distal end which prevents airflow from the air inlet to the air outlet, the self-sealing airflow barrier being breachable upon insertion of at least the distal end of the aerosol generating article into an aerosol generating device to permit airflow from the air inlet to the air outlet.

According to a second aspect of the present disclosure, there is provided an aerosol generating system comprising: an aerosol generating article having a distal end and a mouth end downstream of the distal end, the aerosol generating article comprising: an aerosol generating substrate; a wrapper which circumscribes the aerosol generating substrate and extends between the distal end and the mouth end to form a rod; an air inlet at the distal end and an air outlet at the mouth end; and a self-sealing airflow barrier which prevents airflow from the air inlet to the air outlet; an aerosol generating device including a cavity for receiving at least part of the aerosol generating article and an insertion element configured to breach the self-sealing airflow barrier upon insertion of at least the distal end of the aerosol generating article into the cavity to permit airflow from the air inlet to the air outlet.

According to a specific embodiment of the second aspect, there is provided an aerosol generating system comprising: an aerosol generating article having a distal end and a mouth end downstream of the distal end, the aerosol generating article comprising: an aerosol generating substrate; a wrapper which circumscribes the aerosol generating substrate and extends between the distal end and the mouth end to form a rod; an air inlet at the distal end and an air outlet at the mouth end; and a self-sealing airflow barrier at the distal end which prevents airflow from the air inlet to the air outlet; an aerosol generating device including a cavity for receiving at least part of the aerosol generating article and an insertion element configured to breach the self-sealing airflow barrier upon insertion of at least the distal end of the aerosol generating article into the cavity to permit airflow from the air inlet to the air outlet. According to a third aspect of the present disclosure, there is provided an aerosol generating device for an aerosol generating article having a distal end and a mouth end downstream of the distal end, the aerosol generating article comprising: an aerosol generating substrate; a wrapper which circumscribes the aerosol generating substrate and extends between the distal end and the mouth end to form a rod; an air inlet at the distal end and an air outlet at the mouth end; and a self-sealing airflow barrier at the distal end which prevents airflow from the air inlet to the air outlet; wherein the aerosol generating device includes a cavity for receiving at least part of the aerosol generating article and an insertion element configured to breach the self-sealing airflow barrier upon insertion of at least the distal end of the aerosol generating article into the cavity to permit airflow from the air inlet to the air outlet.

According to a specific embodiment of the third aspect, there is provided an aerosol generating device for an aerosol generating article having a distal end and a mouth end downstream of the distal end, the aerosol generating article comprising: an aerosol generating substrate; a wrapper which circumscribes the aerosol generating substrate and extends between the distal end and the mouth end to form a rod; an air inlet at the distal end and an air outlet at the mouth end; and a self-sealing airflow barrier at the distal end which prevents airflow from the air inlet to the air outlet; wherein the aerosol generating device includes a cavity for receiving at least part of the aerosol generating article and an insertion element configured to breach the self-sealing airflow barrier upon insertion of at least the distal end of the aerosol generating article into the cavity to permit airflow from the air inlet to the air outlet.

The aerosol generating article is configured for use with an aerosol generating device for heating the aerosol generating substrate, without burning the aerosol generating substrate, to volatise at least one component of the aerosol generating substrate and thereby generate a heated vapour which cools and condenses to form an aerosol for inhalation by a user of the aerosol generating device. The aerosol generating device is a hand-held, portable, device.

In general terms, a vapour is a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapour can be condensed to a liquid by increasing its pressure without reducing the temperature, whereas an aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. It should, however, be noted that the terms ‘aerosol’ and ‘vapour’ may be used interchangeably in this specification, particularly with regard to the form of the inhalable medium that is generated for inhalation by a user.

If a user attempts to draw on the mouth end of the aerosol generating article when it is not positioned in an aerosol generating device, the self-sealing airflow barrier prevents airflow from the air inlet to the air outlet and, thus, reduces the likelihood of the user being able to ignite the aerosol generating substrate, for example using an external ignition source, such as a flame, applied to the distal end. This is because there is insufficient airflow through the aerosol generating article to permit ignition and/or sustain combustion of the aerosol generating substrate. The self-sealing nature of the airflow barrier ensures that if it is breached, e.g., pierced or opened or perforated or punctured, such as by an insertion element upon insertion of at least the distal end into an aerosol generating device or by a similar type of piercing element, it self-seals (i.e. reseals) upon removal of the insertion element by fully recovering (i.e. returning to) its initial shape. This ensures that airflow is once again prevented from the air inlet to the air outlet and, thus, that the propensity for ignition and/or sustained combustion of the aerosol generating substrate is eliminated or at least substantially reduced.

The wrapper may comprise a material which is substantially non-electrically conductive and non-magnetically permeable and may, for example, comprise a paper wrapper, e.g., comprising cigarette paper. The use of a wrapper may facilitate manufacture and handing of the aerosol generating article and may enhance aerosol generation. The aerosol generating substrate may be positioned in the wrapper at the distal end. Airflow from the air inlet to the air outlet, through the aerosol generating substrate, is thereby reliably prevented by the self-sealing airflow barrier.

The self-sealing airflow barrier may be positioned upstream of the aerosol generating substrate, for example at the distal end of the aerosol generating article. Put another way, the aerosol generating substrate may be positioned downstream of the self-sealing airflow barrier. By positioning the airflow barrier upstream of the aerosol generating substrate, e.g., at the distal end of the aerosol generating article, manufacture of the aerosol generating article may be facilitated.

The self-sealing airflow barrier may be positioned downstream of the aerosol generating substrate. Put another way, the aerosol generating substrate may be positioned upstream of the self-sealing airflow barrier. With this arrangement, the airflow barrier is not visible at the distal end of the aerosol generating article. This may improve the appearance of the aerosol generating article and may reduce the likelihood of the airflow barrier being damaged and/or removed by a user. It may also facilitate manufacture of the aerosol generating article.

The aerosol generating article may include a pair of said self-sealing airflow barriers which may be positioned upstream and downstream of the aerosol generating substrate, i.e., on opposite sides of the aerosol generating substrate in a longitudinal direction, i.e., a direction extending between the distal end and the mouth end of the aerosol generating article. Both of the self-sealing airflow barriers may be breachable, e.g., pierceable or openable, upon insertion of at least the distal end of the aerosol generating article into an aerosol generating device to permit airflow from the air inlet to the air outlet. By using a pair of self-sealing airflow barriers positioned on opposite sides of the aerosol generating substrate, the aerosol generating substrate may be protected from exposure to oxygen so that degradation of the aerosol generating substrate is reduced and so that freshness and shelf-life are improved. The self-sealing airflow barrier may be secured around its periphery to the wrapper. The self-sealing airflow barrier is reliably secured in position and airflow between the periphery of the self-sealing airflow barrier and the wrapper is prevented, thereby helping to ensure that air cannot flow between the air inlet and the air outlet of the aerosol generating article.

The self-sealing airflow barrier may comprise an elastomeric material. The elastomeric material may comprise silicone rubber. The self-sealing airflow barrier may comprise cork. Although these materials may be preferred, it will be understood by one of ordinary skill in the art that the self-sealing airflow barrier may comprise any material which is capable of self-sealing (i.e. resealing by itself) after being breached, e.g., pierced, punctured, perforated or opened, multiple times, for example by an insertion element such as a piercing lance or needle of the aerosol generating device.

The self-sealing airflow barrier may be formed as a wall made of combustion-resistant material such as silicone or cork. The wall may comprise a pre-weakened area or a prescored or pre-cut area. For example, the self-sealing airflow barrier can be formed of a silicone wall with a single cut slit or a cross cut slit. In relaxed state, the self-sealing airflow barrier is closed and cannot be opened by suction, e.g., applied to the mouth end of the aerosol generating article by a user.

The aerosol generating article may include a vapour cooling element which may be positioned in the wrapper downstream of the aerosol generating substrate. The vapour cooling element promotes cooling of the vapour as it flows from the aerosol generating substrate towards the mouth end to form an aerosol with suitable characteristics for inhalation by a user. The vapour cooling element may comprise a hollow tube, e.g., a hollow paper tube, which may have a wall thickness greater than a thickness of the wrapper. The wall thickness may be at least 1 mm. Manufacture of aerosol generating articles according to the present disclosure is thereby facilitated.

In embodiments in which the self-sealing airflow barrier is positioned downstream of the aerosol generating substrate, the self-sealing airflow barrier may be positioned between the aerosol generating substrate and the vapour cooling element, e.g., between a downstream end of the aerosol generating substrate and an upstream end of the vapour cooling element. Thus, the airflow barrier can be readily combined with the aerosol generating article, and held in position between the aerosol generating substrate and the vapour cooling element, by the wrapper thereby improving the manufacturability of the aerosol generating article.

The self-sealing airflow barrier may be supported by the vapour cooling element, e.g., by an upstream end of the vapour cooling element. In one example, the self-sealing airflow barrier may be secured, e.g., around its periphery, to an upstream end of the vapour cooling element. This may improve the manufacturability of the aerosol generating article by allowing the self-sealing airflow barrier to be combined with the vapour cooling element prior to assembling and wrapping the component parts of the aerosol generating article. In another example, the self-sealing airflow barrier may be secured, e.g., around its periphery, to a downstream end of the aerosol generating substrate. In both examples, the self-sealing airflow barrier is reliably secured in position and airflow through the aerosol generating article is prevented, especially in embodiments in which the wrapper comprises a material which does not allow air to pass therethrough (i.e., in which the wrapper is not air-permeable).

In examples in which the self-sealing airflow barrier is supported by an upstream end of the vapour cooling element, the airflow barrier can be supported by the relatively rigid vapour cooling element as it is breached by the insertion element of the aerosol generating device. In this case, it may be advantageous if the vapour cooling element has a wall thickness of at least 1 mm since this ensures that the vapour cooling element has the necessary level of rigidity to support the self-sealing airflow barrier as it is breached by the insertion element. The wall thickness should not, however, be too large so that the insertion element of the aerosol generating device can pass into the hollow interior of the vapour cooling element.

The aerosol generating article may comprise a mouthpiece filter positioned at the mouth end. The filter may, for example, comprise cellulose acetate fibres and/or paper. The filter may comprise one or more filter segments. Each filter segment may be individually wrapped with a wrapper and the filter segments may be further combined by a combining wrapper.

The aerosol generating substrate may comprise a non-liquid aerosol generating material, for example any type of solid or semi-solid material. Example types of aerosol generating substrate include powder, granules, pellets, shreds, strands, particles, gel, strips, loose leaves, cut leaves, cut filler, porous material, foam material or sheets. The aerosol generating substrate may comprise plant derived material and in particular, may comprise tobacco. It may advantageously comprise reconstituted tobacco, for example including tobacco and any one or more of cellulose fibres, tobacco stalk fibres and inorganic fillers such as CaCO3.

Consequently, the aerosol generating device with which the aerosol generating articles are intended for use may be referred to as a “heated tobacco device”, a “heat-not-bum tobacco device”, a “device for vaporising tobacco products”, and the like, with this being interpreted as a device suitable for achieving these effects. The features disclosed herein are equally applicable to devices which are designed to vaporise any aerosol generating substrate.

The aerosol generating substrate may comprise a plug of aerosol generating material. That is, the aerosol generating substrate may comprise an aerosol generating plug. The aerosol generating substrate may comprise a tobacco plug.

As noted above, the aerosol generating article may be formed substantially in the shape of a rod, and may broadly resemble a cigarette, having a tubular region with an aerosol generating substrate arranged in a suitable manner. The mouthpiece filter may be in coaxial alignment with the aerosol generating substrate. One or more vapour collection regions, cooling regions (e.g., a vapour cooling element as described above), and other structures may also be included in some designs. The aerosol generating substrate may comprise an aerosol-former. Examples of aerosolformers include polyhydric alcohols and mixtures thereof such as glycerine or propylene glycol. Typically, the aerosol generating substrate may comprise an aerosolformer content of between approximately 5% and approximately 50% on a dry weight basis. In some embodiments, the aerosol generating substrate may comprise an aerosolformer content of between approximately 10% and approximately 20% on a dry weight basis, and possibly approximately 15% on a dry weight basis.

Upon heating, the aerosol generating substrate may release volatile compounds. The volatile compounds may include nicotine and/or flavour compounds such as tobacco flavouring.

The heater may be an internal heater which is inserted into the aerosol generating substrate. For example, it may comprise a heating blade or pin.

The heater may comprise an external heater, for example to heat the aerosol generating substrate through the wrapper. For example, the heater may comprise a heating tube comprising a cavity (or heating chamber) dimensioned to receive at least the aerosol generating substrate of the aerosol generating article.

The heater may comprise a resistive heater. The resistive heater may comprise a resistive heating element, for example a resistive heating blade or a resistive heating tube.

The heater may comprise an inductively heatable susceptor and the aerosol generating device may comprise an electromagnetic field generator, such as an induction coil, arranged to generate an alternating electromagnetic field for inductively heating the inductively heatable susceptor. This arrangement provides a particularly convenient way to heat the aerosol generating substrate using induction heating.

The induction coil may comprise a Litz wire or a Litz cable. It will, however, be understood that other materials could be used. The induction coil may be substantially helical in shape and may extend around a cavity (or heating chamber) in which the aerosol generating article is positioned in use. The circular cross-section of a helical induction coil may, for example, facilitate the insertion of the aerosol generating article comprising the aerosol generating substrate and optionally one or more of said inductively heatable susceptors, into the cavity (or heating chamber) and ensures uniform heating of the aerosol generating substrate.

The inductively heatable susceptor may comprise one or more, but not limited, of aluminium, iron, nickel, stainless steel and alloys thereof, e.g. Nickel Chromium or Nickel Copper. With the application of an electromagnetic field in its vicinity, the susceptor may generate heat due to eddy currents and magnetic hysteresis losses resulting in a conversion of energy from electromagnetic to heat.

The induction coil may be arranged to operate in use with a fluctuating electromagnetic field having a magnetic flux density of between approximately 20mT and approximately 2.0T at the point of highest concentration.

The aerosol generating device may include a power source and circuitry which may be configured to operate at a high frequency. The power source and circuitry may be configured to operate at a frequency of between approximately 80 kHz and 500 kHz, possibly between approximately 150 kHz and 250 kHz, and possibly at approximately 200 kHz. The power source and circuitry could be configured to operate at a higher frequency, for example in the MHz range, depending on the type of inductively heatable susceptor that is used.

The insertion element of the aerosol generating device may be a piercing element and may be hollow. The hollow insertion element, e.g., hollow piercing element, may be configured to pierce the self-sealing airflow barrier (or the pair of self-sealing airflow barriers, where present) upon insertion of at least the distal end of the aerosol generating article into the cavity to permit airflow from the air inlet to the air outlet through the hollow piercing element and the aerosol generating substrate. Thus, the insertion element may conveniently have a dual -function (piercing and directing airflow through the aerosol generating substrate), thereby simplifying the structure of the aerosol generating device.

The hollow insertion element, e.g., piercing element, may comprise a one-way valve. The one-way valve may, for example, be a duckbill valve or slit valve. The use of a one-way valve helps to ensure that airflow through the aerosol generating substrate is only in the direction from the air inlet to the air outlet, and not in the opposite direction.

The hollow insertion element, e.g., piercing element, may be substantially conical or substantially frustoconical. Such a shape may facilitate piercing or enlargement of the self-sealing airflow barrier and/or may facilitate removal of a used aerosol generating article from the cavity of the aerosol generating device and/or may help to promote selfsealing (i.e. resealing) of the self-sealing airflow barrier after removal of the aerosol generating article from the cavity of the aerosol generating device.

The insertion element, e.g., piercing element, may be arranged at a distal end of the cavity. The insertion element may project into the cavity, for example from the distal end towards a proximal end. This may help to simplify the structure of the aerosol generating device.

The aerosol generating device may comprise a plurality of said insertion elements. Thus, the self-sealing airflow barrier may be breached, e.g., pierced or punctured or opened or perforated, at multiple locations, thereby promoting airflow through the aerosol generating substrate and reducing the resistance-to-draw.

Brief Description of the Drawings

Figure 1 is diagrammatic cross-sectional view of a first example of an aerosol generating article;

Figure 2 is a diagrammatic cross-sectional view of a first example of an aerosol generating system comprising a first example of an electrically-operated aerosol generating device and the aerosol generating article illustrated in Figure 1; Figure 3 is a diagrammatic cross-sectional view of a second example of an aerosol generating system comprising a second example of an electrically-operated aerosol generating device and the aerosol generating article illustrated in Figure 1;

Figure 4 is diagrammatic cross-sectional view of a second example of an aerosol generating article; and

Figure 5 is diagrammatic cross-sectional view of a third example of an aerosol generating article.

Detailed Description of Embodiments

Embodiments of the present disclosure will now be described by way of example only and with reference to the accompanying drawings.

Referring to Figure 1, there is shown diagrammatically an example of an aerosol generating article 10. The aerosol generating article 10 is elongate and substantially cylindrical and is of a so-called "stick" type. The aerosol generating article 10 has a distal (or upstream) end 12 and a mouth (or downstream) end 14.

The aerosol generating article 10 comprises the following elements arranged sequentially and in co-axial alignment in a downstream direction, in other words from the distal end 12 to the mouth end 14: an aerosol generating substrate 16, an optional vapour cooling element 18, and an optional filter 20, for example comprising cellulose acetate fibres. The elements are all assembled inside a wrapper 22 to form a rod, and the wrapper 22 holds the elements in position to form the aerosol generating article 10. The wrapper 22 is substantially non-electrically conductive and non-magnetically permeable, and typically comprises a paper wrapper, e.g., cigarette paper.

The aerosol generating substrate 16 comprises a solid or semi-solid material (i.e. anon- liquid material) and may comprise plant derived material, and in particular tobacco. The aerosol generating substrate 16 typically comprises a tobacco plug. The aerosol generating substrate 16 may include an aerosol-former, such as glycerine or propylene glycol, to facilitate the generation of a vapour or aerosol when heated. The vapour cooling element 18 typically comprises a hollow paper tube 18a having a thickness which is greater than the thickness of the paper wrapper 22. As heated vapour flows through the vapour cooling element 18 in the downstream direction, from the aerosol generating substrate 16 towards the mouth end 14, the vapour cools and condenses to form an aerosol with suitable characteristics for inhalation by a user. The vapour cooling element 18 (e.g. hollow paper tube 18a) may contact the aerosol generating substrate 16 at a first end as shown in Figure 1, but can be spaced from the aerosol generating substrate 16 in other embodiments.

The aerosol generating article 10 has an air inlet 24 at the distal end 12 and an air outlet 26 at the mouth end 14. A self-sealing airflow barrier 28 is positioned at the distal end 12 of the aerosol generating article 10. The self-sealing airflow barrier 28 comprises a self-sealing material, typically an elastomeric material such as silicone rubber or cork and is secured around its periphery to the wrapper 22. The self-sealing airflow barrier 28 prevents airflow from the air inlet 24 to the air outlet 26 through the aerosol generating substrate 16, and this reduces the propensity for ignition and/or sustained combustion of the aerosol generating substrate 16.

Referring now to Figure 2, there is shown diagrammatically a first example of an aerosol generating system 1. The aerosol generating system 1 comprises a first example of an electrically-operated aerosol generating device 30 and an aerosol generating article 10 as described above.

The aerosol generating device 30 has a first (or proximal) end 32 and a second (or distal) end 34 and comprises a device housing 36. The aerosol generating device 30 further comprises a cavity (i.e. heating chamber) 38 having a substantially cylindrical crosssection, a power source 40, for example one or more batteries, and a controller 42 which are all positioned in the device housing 36. The aerosol generating device 30 is a handheld, portable, device, by which it is meant that a user is able to hold and support the device unaided, in a single hand. The cavity 38 has a proximal end 44 and a distal end 46, and includes an opening 48 at the proximal end 44. In the illustrated embodiment, the cavity 38 includes a substantially cylindrical side wall 50, i.e., a side wall 50 which has a substantially circular cross-section. The aerosol generating article 10 is positioned in the cavity 38 by inserting the distal end 12 into the cavity 38 via the opening 48. The cavity 38 and aerosol generating article 10 are dimensioned so that the mouth end 14, and in particular the filter 20, projects from the cavity 38 at the first (proximal) end 44 to permit engagement by a user’s lips.

The aerosol generating device 30 includes an insertion element 52, in the illustrated example a hollow piercing element 52 which is arranged at the distal end 46 of the cavity 38 and which projects into the cavity 38 from the distal end 46 towards the proximal end 44. The hollow piercing element 52 has a frustoconical outer surface 54 and may comprise a one-way valve, e.g. duckbill valve. When the aerosol generating article 10 is fully inserted into the cavity 38 as shown in Figure 2, the hollow piercing element 52 pierces the self-sealing airflow barrier 28, allowing air to flow through the aerosol generating article 10, from the air inlet 24 to the air outlet 26.

The aerosol generating device 30 includes a heater 58 for heating the aerosol generating substrate 16 without burning the aerosol generating substrate 16. In the illustrated example, the heater 58 is a resistive heater which coextends with the side wall of the cavity 38, and may comprise a resistive heating tube.

During operation of the aerosol generating device 30, electrical energy is supplied by the power source 40 and controller 42 to the resistive heater 58 which is thereby heated. The heat is transferred from the resistive heater 58 to the aerosol generating substrate 16 of the aerosol generating article 10, for example by conduction, radiation and convection, causing the aerosol generating substrate 16 to heat up without burning and thereby produce a vapour. When a user draws (i.e. sucks) on the mouth end 14 of the aerosol generating article 10, air is drawn through the aerosol generating article 10 via an airflow passage 56 in the device housing 36. The air flows through the hollow piercing element 52 and the air inlet 24 of the aerosol generating article 10. The air then flows through the aerosol generating substrate 16 and, hence, vapour generated by heating the aerosol generating substrate 16 is entrained in the airstream and conveyed towards the air outlet 28 at the mouth end 14 of the aerosol generating article 10. The vapour cools and condenses as it flows through the vapour cooling element 18 to form an aerosol. The aerosol then passes through the filter 20 and is inhaled by a user.

When the aerosol generating article 10 is removed from the cavity 38, the self-sealing airflow barrier 28 recovers its original shape, thereby sealing the small opening created in the airflow barrier 28 by the hollow piercing element 52. Thus, the self-sealing airflow barrier 28 once again prevents airflow from the air inlet 24 to the air outlet 26 of the aerosol generating article 10, reducing the propensity for ignition and/or sustained combustion of the aerosol generating substrate 16.

Referring to Figure 3, there is shown diagrammatically a second example of an aerosol generating system 2. The aerosol generating system 2 is similar to the aerosol generating system 1 described above with reference to Figure 2, and corresponding components are identified using the same reference numerals.

The aerosol generating system 2 comprises a second example of an electrically- operated aerosol generating device 60 and an aerosol generating article 10 as described above.

The aerosol generating device 60 comprises a magnetic field generator 62 for generating an electromagnetic field. The magnetic field generator 62 comprises a substantially helical induction coil 64. The induction coil 64 has a circular cross-section and extends around the substantially cylindrical cavity 38. The induction coil 64 can be energised by the power source 40 and controller 42. The controller 42 includes, amongst other electronic components, an inverter which is arranged to convert a direct current from the power source 40 into an alternating high-frequency current for the induction coil 64. The aerosol generating system 2 further includes an inductively heatable susceptor located proximate, or in contact with, the aerosol generating substrate 16. The inductively heatable susceptor may, for example, comprise a blade-shaped susceptor, a pin-shaped susceptor or tube-shaped susceptor which coextends with the side wall of the cavity 38. The inductively heatable susceptor may alternatively comprise a susceptor element which is positioned in, or particulate susceptor material which is dispersed throughout, the aerosol generating substrate 16 during manufacture and assembly of the aerosol generating article 10.

Irrespective of the particular configuration of the inductively heatable susceptor, and as will be understood by one of ordinary skill in the art, when the induction coil 64 is energised during use of the aerosol generating system 2, an alternating and time-varying electromagnetic field is produced. This couples with the inductively heatable susceptor and generates eddy currents and/or magnetic hysteresis losses in the susceptor causing it to heat up. The heat is then transferred from the inductively heatable susceptor to the aerosol generating substrate 16, for example by conduction, radiation and convection, to heat the aerosol generating substrate 16 without burning and thereby produce a vapour. Airflow through the aerosol generating device 60, and hence through the aerosol generating article 10, is the same as that described above in connection with the aerosol generating system 1 of Figure 2.

Referring to Figure 4, there is shown a second example of an aerosol generating article 70 which is similar to the aerosol generating article 10 described above with reference to Figure 1 and in which corresponding components are identified using the same reference numerals.

The aerosol generating article 70 comprises a pair of self-sealing airflow barriers 28 as described above positioned on opposite sides of the aerosol generating substrate 16 in a longitudinal direction of the aerosol generating article 70. Both of the self-sealing airflow barriers 28 are pierced upon insertion of the aerosol generating article 70 into the cavity 38 of the aerosol generating device 30, 60 to permit airflow from the air inlet 24 to the air outlet 26. For example, the aerosol generating device 30, 60 can include an elongate hollow piercing element 52 which has a sufficient length in the longitudinal direction to pierce both of the self-sealing airflow barriers 28.

Referring to Figure 5, there is shown a third example of an aerosol generating article 80 which is similar to the aerosol generating articles 10 described above with reference to Figure 1 and in which corresponding components are identified using the same reference numerals.

The aerosol generating article 80 comprises a single self-sealing airflow barrier 28 positioned downstream of the aerosol generating substrate 16, between the aerosol generating substrate 16 and the vapour cooling element 18. In this example, it will be understood that there is no self-sealing airflow barrier 28 at the distal end 12 of the aerosol generating article 70.

In general, the self-sealing airflow barrier 28 used in all of the examples described above can be an elastic wall of constant thickness or, alternatively of locally reduced thickness to facilitate piercing or perforation by the piercing element 52. For example, the wall can comprise a pre-weakened area in the region intended to be pierced or perforated. The pre-weakened area can be shaped as a small circle or can be linear or cross-shaped in the transverse direction. The self-sealing airflow barrier 28 can be made of combustion-resistant material such silicone or cork.

In a possible mode, the self-sealing airflow barrier 28 is a pre-cut or pre-scored elastic wall that is closed in the relaxed state and is forced to open by the insertion element 52. When the self-sealing airflow barrier 28 has a slit or slits, the self-sealing airflow barrier 28 cannot be opened by a user’s suction at the mouth end 14 of the aerosol generating article 10 due to a too high resistance to draw.

Although exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications may be made to those embodiments without departing from the scope of the appended claims. Thus, the breadth and scope of the claims should not be limited to the above-described exemplary embodiments. Any combination of the above-described features in all possible variations thereof is encompassed by the present disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

Claims

1. An aerosol generating article (10, 70, 80) having a distal end (12) and a mouth end (14) downstream of the distal end (12), the aerosol generating article (10, 70, 80) comprising: an aerosol generating substrate (16); a wrapper (22) which circumscribes the aerosol generating substrate (16) and extends between the distal end (12) and the mouth end (14) to form a rod; an air inlet (24) at the distal end (12) and an air outlet (26) at the mouth end (14); and a self-sealing airflow barrier (28) which prevents airflow from the air inlet (24) to the air outlet (26), the self-sealing airflow barrier (28) being breachable upon insertion of at least the distal end (12) of the aerosol generating article (10, 70, 80) into an aerosol generating device (30, 60) to permit airflow from the air inlet (24) to the air outlet (26).

2. An aerosol generating article according to claim 1, wherein the self-sealing airflow barrier (28) is positioned upstream of the aerosol generating substrate (16).

3. An aerosol generating article according to claim 1 or claim 2, wherein the selfsealing airflow barrier (28) is positioned downstream of the aerosol generating substrate (16).

4. An aerosol generating article according to any preceding claim, wherein the aerosol generating substrate (16) is positioned in the wrapper (22) at the distal end (12).

5. An aerosol generating article according to any preceding claim, wherein the self-sealing airflow barrier (28) is secured around its periphery to the wrapper (22).

6. An aerosol generating article according to any preceding claim, wherein the self-sealing airflow barrier (28) comprises an elastomeric material, preferably silicone rubber.

7. An aerosol generating article according to any preceding claim, wherein the aerosol generating article (10, 70, 80) includes a vapour cooling element (18) positioned in the wrapper (22) downstream of the aerosol generating substrate (16), preferably wherein the vapour cooling element (18) comprises a hollow tube (18a).

8. An aerosol generating article according to claim 7, wherein the hollow tube (18a) is a paper tube having a thickness which is greater than a thickness of the wrapper (22).

9. An aerosol generating article according to claim 7 or claim 8, wherein the selfsealing airflow barrier (28) is positioned between the aerosol generating substrate (16) and the vapour cooling element (18).

10. An aerosol generating article according to any preceding claim, further comprising a mouthpiece filter (20) at the mouth end (14).

11. An aerosol generating system (1, 2) comprising: an aerosol generating article (10, 70, 80) having a distal end (12) and a mouth end (14) downstream of the distal end (12), the aerosol generating article (10, 70, 80) comprising: an aerosol generating substrate (16); a wrapper (22) which circumscribes the aerosol generating substrate (16) and extends between the distal end (12) and the mouth end (14) to form a rod; an air inlet (24) at the distal end (12) and an air outlet (26) at the mouth end (14); and a self-sealing airflow barrier (28) which prevents airflow from the air inlet (24) to the air outlet (26); an aerosol generating device (30, 60) including a cavity (38) for receiving at least part of the aerosol generating article (10, 70, 80) and an insertion element (52) configured to breach the self-sealing airflow barrier (28) upon insertion of at least the distal end (12) of the aerosol generating article (10, 70, 80) into the cavity (38) to permit airflow from the air inlet (24) to the air outlet (26).

12. An aerosol generating system according to claim 11, wherein the insertion element (52) is a hollow insertion element configured to breach the self-sealing airflow barrier (28) upon insertion of at least the distal end (12) of the aerosol generating article (10, 70, 80) into the cavity (38) to permit airflow from the air inlet (24) to the air outlet (26) through the hollow insertion element (52) and the aerosol generating substrate (16).

13. An aerosol generating system according to claim 12, wherein the hollow insertion element (52) comprises a one-way valve, preferably a duckbill valve or slit valve.

14. An aerosol generating system according to claim 12 or claim 13, wherein the hollow insertion element (52) is substantially conical or substantially frustoconical.

15. An aerosol generating system according to any of claims 12 to 14, wherein the hollow insertion element (52) is arranged at a distal end (46) of the cavity (38).

16. An aerosol generating system according to claim 15, wherein the hollow insertion element (52) projects into the cavity (38), from the distal end (46) towards a proximal end (44).

17. An aerosol generating system according to any of claims 11 to 16, wherein the aerosol generating device (30, 60) comprises a plurality of said insertion elements (52).