WO2024240644A1

WO2024240644A1 - Aerosol generating device configured to operate with a flat-shaped tobacco article and assembly comprising such aerosol generating device

Info

Publication number: WO2024240644A1
Application number: PCT/EP2024/063701
Authority: WO
Inventors: Alec WRIGHT
Original assignee: JT International SA
Current assignee: JT International SA
Priority date: 2023-05-19
Filing date: 2024-05-17
Publication date: 2024-11-28
Anticipated expiration: 2025-11-19

Abstract

An aerosol generating device (11) is configured to operate with a flat-shaped tobacco article and comprising a flat-shaped heating chamber (38) extending along a device longitudinal axis (Y) between a proximal end configured to receive at least a tobacco portion (15) of the flat-shaped tobacco article and a distal end (42) opposite to the proximal end; wherein the aerosol generating device (11 ) comprises a rear portion (54) extending between the distal end (42) of the flat-shaped heating chamber (38) and a distal wall (50) of a device housing (34), the rear portion (54) defining one single inlet channel (56) configured to provide an airflow into the heating chamber (38), the single inlet channel (56) extending along the device longitudinal axis (Y) and presenting a plurality of cross sections.

Description

Aerosol generating device configured to operate with a flat-shaped tobacco article and assembly comprising such aerosol generating device

FIELD OF THE INVENTION

The present invention concerns an aerosol generating device configured to operate with a flat-shaped tobacco article. The aerosol generating device comprises a flat-shaped heating chamber. The invention further concerns an aerosol generating assembly comprising an aerosol generating device and a flat-shaped tobacco article.

Particularly, the flat-shaped tobacco article comprises for example a solid substrate able to form aerosol when being heated. Thus, such type of aerosol generating devices, also known as heat-not-burn devices, is adapted to heat, rather than burn, the substrate by conduction, convection and/or radiation, to generate aerosol for inhalation.

BACKGROUND OF THE INVENTION

The popularity and use of reduced-risk or modified-risk devices (also known as vaporisers) has grown rapidly in the past few years as an aid to assist habitual smokers wishing to quit smoking traditional tobacco products such as cigarettes, cigars, cigarillos, and rolling tobacco. Various devices and systems are available that heat or warm vaporizable substances as opposed to burning tobacco in conventional tobacco products.

A commonly available reduced-risk or modified-risk device is the heated substrate aerosol generation device or heat-not-burn device. Devices of this type generate aerosol or vapour by heating an aerosol substrate that typically comprises moist leaf tobacco or other suitable vaporizable material to a temperature typically in the range 150°C to 350°C. Heating an aerosol substrate, but not combusting or burning it, releases aerosol that comprises the components sought by the user but not the toxic and carcinogenic byproducts of combustion and burning. Furthermore, the aerosol produced by heating the tobacco or other vaporizable material does not typically comprise the burnt or bitter taste resulting from combustion and burning that can be unpleasant for the user and so the substrate does not therefore require the sugars and other additives that are typically added to such materials to make the smoke and/or vapour more palatable for the user. Aerosol generating devices and their heating chambers can present different shapes or geometries. Depending on the shapes, airflows passing through the devices may differ in various locations inside the device. As a consequence, for example, a generated aerosol may accumulate at specific edges inside the device. In particular, in some devices, specific portions of the tobacco article may be submitted to a higher vapour extraction, in particular due to large amounts of air passing by these portions, compared with other portions. Thus, in some areas, large quantities of aerosol may be extracted from the tobacco article, whereas in other areas, smaller quantities of aerosol may be extracted, leading for example to a non-optimal consumption of the tobacco article. This may have an impact on user experience and user comfort.

Thus, some known aerosol generating devices can still be improved in terms of user comfort.

SUMMARY OF THE INVENTION

One of the aims of the invention is to provide an aerosol generating device configured to operate with a flat-shaped tobacco article, which allows improving user comfort, in particular which allows improving air distribution through the flat-shaped tobacco article.

For this purpose, the invention relates to an aerosol generating device configured to operate with a flat-shaped tobacco article and comprising a flat-shaped heating chamber extending along a device longitudinal axis between a proximal end configured to receive at least a tobacco portion of the flat-shaped tobacco article and a distal end opposite to the proximal end; wherein the aerosol generating device comprises a rear portion extending between the distal end of the flat-shaped heating chamber and a distal wall of a device housing, the rear portion defining one single inlet channel configured to provide an airflow into the heating chamber; the single inlet channel extending along the device longitudinal axis and presenting a plurality of cross sections perpendicular to the device longitudinal axis, wherein at least one cross section of the plurality of cross sections is substantially rectangular and presents a shape substantially equal to a tobacco cross section of the tobacco portion adjacent to said at least one cross section. Thanks to these features, user comfort is improved, because the single inlet channel presents the substantially rectangular cross-section which is substantially equal to the tobacco cross section. This allows to improve the airflow through the device having a flatshaped heating chamber configured to receive a flat-shaped tobacco article. Indeed, thanks to these features, an airflow passing through the inlet channel may present less or no turbulences and present a laminar flow. Thus, aerosol extraction may be improved over the total surface of the tobacco article. Additionally, these features allow to reduce any negative pressure pockets that may lead to condensation in the heating chamber. Indeed, thanks to the laminar airflow, such condensation is reduced. Contrary to these features, an airflow may present turbulences in case of a transition from an inlet channel having a circular cross section at the transition discharging into a flat-shaped heating chamber. Such transition between a circular cross section and the flat shape of the heating chamber may lead to lower aerosol extraction and/or generation of condensate inside the heating chamber or at the transition between the single inlet channel and the heating chamber, contrary of the features of the aerosol generating device according to the present disclosure.

In particular, as the at least one cross section presents a shape substantially equal to the tobacco cross section of the tobacco portion that is arranged adjacent to this cross section, a smooth airflow transition between the single inlet channel and the distal end of the heating chamber is provided. Preferably, the shape of the inlet channel may match that of the tobacco article where the two make contact.

Preferably, the single inlet channel may be formed so that the airflow may stick to lateral walls of the inlet channel. In particular, the single inlet channel may present a shape able to increase the airflow close to the walls of the inlet channel compared with a central area of the inlet channel thanks to the Coanda effect. Such a shape may be a curved inner lateral wall of the inlet channel for example. According to other examples, the inlet channel may be delimited by straight lateral walls for example, extending for example in parallel to the device longitudinal axis or according to a constant angle formed between the walls and the device longitudinal axis. In order to obtain the Coanda effect in this case, for example, the inlet channel may present a curved transition from an external surface of the device to the straight lateral walls. In particular, the Coanda effect describes the tendency of an airflow or a jet to stay attached to a convex surface, such as here for example the walls of the inlet channel. Of course, the different shapes of the single inlet channel may be combined according to examples. Thanks to the inlet channel configured to provide the airflow sticking to the walls of the inlet channel, a high amount of air may be provided to an outer surface of the tobacco article, extending in parallel to the device longitudinal axis. This allows to generate large quantities of aerosol at the outer surface of the tobacco article. This may be particularly advantageous if the tobacco article has a high tobacco density, so that an airflow through the tobacco is unlikely to occur. In particular, in this case, aerosol may be generated mostly on the outer surfaces of the tobacco article, which is enhanced thanks to the features of the inlet channel.

By the expression “single inlet channel”, it is understood that a rear portion of the device presents only one inlet channel configured to provide air into the heating chamber. In particular, the rear portion, and in particular the distal wall, may present only one opening. In particular, the device as a whole may present only one air inlet into the heating chamber, that is the single inlet channel. For example, the device presents the one inlet channel for receiving air in the heating chamber at the distal end, and may further present an air outlet at the proximal end configured for provide the airflow with aerosol to the user. According to other examples, the device may present additional inlets at lateral walls of the device.

By “cross section perpendicular to the device longitudinal axis”, it is understood a corresponding cross section that extends according a plane that is oriented perpendicular to the device longitudinal axis.

According to examples, the cross section of the inlet channel adjacent to the tobacco cross section may present a height substantially equal to 1 ,2 mm and/or a width substantially equal to 1 1 ,5 mm.

According to some embodiments, the single inlet channel is delimited, along the device longitudinal axis, by a channel inlet cross section defining an airflow inlet and by a channel outlet cross section adjacent to the heating chamber, wherein the channel outlet cross section presents a substantially rectangular shape.

Thanks to these features, the airflow is laminar, in particular at the transition between the inlet channel and the heating chamber, because the outlet cross section has the substantially rectangular shape and is thus adapted to the flat shape of the heating chamber. According to some embodiments, the single inlet channel is delimited, according to directions perpendicular to the device longitudinal axis, by at least one inner surface, the inner surface connecting the channel inlet cross section to the channel outlet cross section, wherein the inner surface forms at each point an angle with the device longitudinal axis less than 90°.

Thanks to these features, the airflow may traverse the inlet channel easily, in particular without entering in contact with obstacles, such as steps of the inner surface, which may be susceptible to slow down or perturb the airflow.

According to some embodiments, the inner surface presents a smooth transition between the channel inlet cross section and the channel outlet cross section.

Thanks to these features, the airflow guided by the inlet channel between the channel inlet cross section and the channel outlet cross section presents no or very low turbulences, leading to improved vapor extraction in the heating chamber. In addition, the inlet channel may be manufactured in an easy and fast manner.

According to some embodiments, the at least one inner surface defines at least one straight line connecting an edge of the substantially rectangular shape of the channel outlet cross section with the channel inlet cross section.

Thanks to these features, the inlet channel allows to provide a laminar airflow to the tobacco article, as the inlet channel travels in a linear or straight line from the channel inlet cross section towards the tobacco portion. For example, the inlet channel allows guiding the airflow in parallel to the straight line(s), so as to present very low turbulence of the airflow. The straight lines may extend parallel to each other or present a decreasing distance to each other along the device longitudinal axis.

According to some embodiments, a maximum width of the single inlet channel at the channel inlet cross section is smaller than a maximum width of the single inlet channel at the channel outlet cross section, each maximum width being defined along to a direction perpendicular to the device longitudinal axis.

Thanks to these features, the inlet channel allows to adapt, on the one hand, a part of the inlet channel, i.e. the channel outlet cross section, to the flat-shaped heating chamber, and on the other hand, to choose another shape of the channel inlet cross section. Furthermore, these features allow to facilitate for example production of the inlet channel, in particular if the inlet channel presents very small dimensions.

According to some embodiments, the channel inlet cross section presents a shape different from a rectangular shape. For example, the channel inlet cross section may present a circular shape or an elliptic shape.

Thanks to these features, the inlet channel allows a transition of the shape between the channel inlet cross section and the channel outlet cross section. This allows in particular to manufacture the inlet channel in an easy manner.

For example, the inlet channel may blend from the shape of the channel inlet cross section to the shape of the channel outlet cross section, so as to present the rectangular channel outlet cross section.

According to some examples, the respective areas of all cross sections of the inlet channel may be constant. In addition, for example, the maximum width at the channel inlet cross section may be smaller than the maximum width at the channel outlet cross section. By “area of cross section”, it is understood the size of the channel according to the cross section, for example in square millimetres. In this case, the inlet channel may present a transition or blending from a circular shape or an elliptic shape of the channel inlet cross section to the rectangular shape of the channel outlet cross section, by maintaining the same area at each cross section of the inlet channel. This allows to obtain different shapes of the cross sections of the inlet channel between the channel inlet cross section and the channel outlet cross section.

According to some examples, the area of the channel inlet cross section, having for example circular shape, may be smaller than the area of the channel outlet cross section, having the rectangular shape. This allows in particular to increase a pressure drop of the airflow adjacent to the channel inlet cross section. Furthermore, this allows to manufacture the inlet channel in an easy manner. Indeed, despite a small area of the channel inlet cross section, the diameter of the channel inlet cross section of circular shape may be larger than minimum diameter of a cross section of having the same area, but presenting a rectangular shape. In some cases, it may be challenging to machine a channel with very small channel diameters, such as smaller than 1 ,2 mm, and thanks to these features, larger diameters of the channel may be used, and a high pressure drop of the airflow may still be obtained. By “pressure drop”, it is in particular understood a difference of air pressure inside the inlet channel compared with an air pressure outside the inlet channel, i.e. of air prior to entering the inlet channel.

According to some embodiments, each cross section of the plurality of cross sections is substantially rectangular.

Thanks to these features, the inlet channel presents a simple structure. In addition, for example, the inlet channel matches the shape of the flat-shaped heating chamber, which allows efficient aerosol generation.

According to some embodiments, the single inlet channel presents a rounded transition with an external surface of the distal wall of the device housing.

Thanks to these features, the Coanda effect of the airflow entering the inlet channel is enhanced. In particular, if air from the outside is drawn into the inlet channel, thanks to the rounded transition from the external surface into the inlet channel, the airflow or jet sticks to the inner surface(s) of the inlet channel.

According to some embodiments, a distance, according to the device longitudinal axis, between the distal wall of the device housing and the distal end of the flat-shaped heating chamber defines a channel length, wherein the channel length is longer than a heating chamber length corresponding to a distance between the proximal end and the distal end according to the device longitudinal axis.

Thanks to these features, the inlet channel presents a length, also called channel length, that is large, such as for example a length larger than 10 mm, preferably larger than 15 mm or even larger than 17 mm or 20 mm. Thus, the inlet channel is adapted to provide a laminar airflow or an airflow having very few turbulences to the flat-shaped heating chamber. This improves extraction of aerosol.

According to some embodiments, an area defined by the at least one cross section matches and/or covers completely an area defined by the tobacco cross section. Thanks to these features, the airflow is further improved. In particular, if the cross section matches the area defined by the tobacco cross section, a smooth transition of the airflow from the inlet channel to the tobacco cross section is obtained.

For example, the at least one cross section of the inlet channel adjacent to the tobacco cross section may present a shape identical to an outline of the tobacco article, such as for example 17 mm x 11 ,5 mm x 1 ,2 mm. This at least one cross section is in particular the channel outlet cross section.

According to some embodiments, at least one outer surface of the tobacco article extending along an article axis presents a plurality of grooves forming air channels.

Thanks to these features, the tobacco article is very compact and presents at the same time a large surface for aerosol extraction. In particular, the grooves allow increasing the surface adapted to enter in contact with the airflow upon heating in the heating chamber.

The invention further relates to an assembly comprising the aerosol generating device as described above, further comprising the flat-shaped tobacco article having the tobacco portion received in the flat-shaped heating chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and its advantages will be better understood upon reading the following description, which is given by way of non-limiting example and which is made with reference to the appended drawings, in which:

- Figure 1 is a schematic perspective view of an aerosol generating assembly, the aerosol generating assembly comprising an aerosol generating device according to the invention and a tobacco article usable with the aerosol generating device;

- Figure 2 is a perspective view of the tobacco article of Figure 1 ;

- Figure 3 is a schematic cross-sectional view according to a first plane of the aerosol generating assembly of Figure 1 , wherein the first plane comprises a device longitudinal axis of the aerosol generating device and wherein the aerosol generating assembly is according to a first embodiment; - Figure 4 is a schematic cross-sectional view of the aerosol generating assembly of Figure 3 according to a second plane perpendicular to the first plane and comprising the device longitudinal axis;

- Figure 5 schematic rear view of the aerosol generating assembly of Figure 3 along a direction of the device longitudinal axis, illustrating an external surface of the aerosol generating device extending perpendicular to the device longitudinal axis;

- Figure 6 is a schematic cross-sectional view of the aerosol generating assembly according to a second embodiment, analogous to the view of Figure 3;

- Figure 7 is a schematic cross-sectional view of the aerosol generating assembly according to the second embodiment, analogous to the view of Figure 4;

- Figure 8 is a schematic cross-sectional view of the aerosol generating assembly according to the second embodiment, analogous to the view of Figure 5, and

- Figure 9 is a cross-sectional view of the tobacco article of Figure 1 inserted into a heating chamber of the aerosol generating device, illustrating an area of enhanced airflow according to the Coanda effect.

DETAILED DESCRIPTION OF THE INVENTION

Before describing the invention, it is to be understood that it is not limited to the details of construction set forth in the following description. It will be apparent to those skilled in the art having the benefit of the present disclosure that the invention is capable of other embodiments and of being practiced or being carried out in various ways.

As used herein, the term “cross section” may be defined as a cross section extending in a plane perpendicular to a device longitudinal axis or an article axis. For example, if the cross section relates to a part of the aerosol generating device, such cross section extends in a plane perpendicular to the device longitudinal axis. Preferably, all cross sections may extend in parallel one to each other. For example, each cross section of a plurality of cross sections of a single inlet channel, including a channel inlet cross section and a channel outlet cross section, may extend parallel to each other, in particular perpendicular to the device longitudinal axis. For example, a tobacco cross section forms a cross section of the tobacco article, wherein this cross section extends in a plane perpendicular to the article axis. If the article axis extends in parallel to the device longitudinal axis or is identical to this axis, in particular upon insertion of the tobacco article into the aerosol generating device, the or each tobacco cross section may extend in parallel to each cross section of the plurality of cross sections of the single inlet channel.

The expression “substantially equal to” is understood hereinafter as an equality at plus or minus 10% and preferably at plus or minus 5%, and even more preferably at plus or minus 1%. According to some examples, this expression may designate exact equality. For example, by “substantially rectangular” or “substantially rectangular shape”, it is understood that adjacent edges of the shape defining the rectangle may form between each other an angle substantially equal to 90°, that is for example an angle deviating from 90° by plus or minus 10%, preferably by plus or minus 5%, and even more preferably by plus or minus 1%. According to some examples, by “substantially rectangular” or “substantially rectangular shape”, it is understood “rectangular” or “rectangular shape”.

Hence, if at least one reference cross section of a plurality of cross sections of a first element is substantially rectangular and presents a shape substantially equal to a cross section of a second element, it is clear firstly that the reference cross section and the cross section of the second element are both substantially rectangular and, secondly, that the characterizing dimensions of the reference cross section, including side length(s) and/or angle(s) between two adjacent sides, and the corresponding characterizing dimensions of the cross section of the second element are equal within the meaning of the preceding paragraph.

In other words, determining if two shapes are substantially equal” involves taking into account both the type of shape (e.g. rectangular, triangular, etc.) and the characterizing dimensions of the shape.

If the reference cross section has a shape substantially equal to the cross section of the second element, the reference cross section approximately matches the cross section of the second element. In case of an exact equality, the reference cross section exactly matches the cross section of the second element. As used herein, the term “aerosol generating device” or “device” may include a vaping device to deliver an aerosol to a user, including an aerosol for vaping, by means of a heater element explained in further detail below. The device may be portable. “Portable” may refer to the device being for use when held by a user. The device may be adapted to generate a variable amount of aerosol, e.g. by activating the heater element for a variable amount of time (as opposed to a metered dose of aerosol), which can be controlled by a trigger. The trigger may be user activated, such as a vaping button and/or inhalation sensor. The inhalation sensor may be sensitive to the strength of inhalation as well as the duration of inhalation to enable a variable amount of vapour to be provided (so as to mimic the effect of smoking a conventional combustible smoking article such as a cigarette, cigar or pipe, etc.). The device may include a temperature regulation control to drive the temperature of the heater and/or the heated aerosol generating substance (aerosol pre-cursor) to a specified target temperature and thereafter to maintain the temperature at the target temperature that enables efficient generation of aerosol.

As used herein, the term “aerosol” may include a suspension of vaporizable material as one or more of: solid particles; liquid droplets; gas. Said suspension may be in a gas including air. Aerosol herein may generally refer to/include a vapour. Aerosol may include one or more components of the vaporizable material.

As used herein, the term “vaporizable material” or “precursor” may refer to a smokable material which may for example comprise nicotine or tobacco and an aerosol former. Tobacco may take the form of various materials such as shredded tobacco, granulated tobacco, tobacco leaf and/or reconstituted tobacco. Suitable aerosol formers include: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, acids such as lactic acid, glycerol derivatives, esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerin or vegetable glycerin. In some embodiments, the aerosol generating agent may be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. The substrate may also comprise at least one of a gelling agent, a binding agent, a stabilizing agent, and a humectant.

FIRST EMBODIMENT

With reference to Figures 1 to 5, an aerosol generating assembly 10 according to a first embodiment comprises an aerosol generating device 1 1 and a flat-shaped aerosol generating article 12, also called flat-shaped tobacco article 12. The aerosol generating device 11 is intended to operate with the flat-shaped tobacco article 12 which is shown in more detail in Figure 2. The flat-shaped tobacco article 12 is called tobacco article 12 hereafter.

With reference to Figure 2, the tobacco article 12 presents for example a flat-shaped cuboid extending along an article axis X1 and having external dimensions LxWxD. In a typical example, the length L of the article 12 according to the article axis X1 equals substantially to 32 mm while its width W and depth D are substantially equal respectively to 11 ,5 mm and 1 ,2 mm. According to different examples, the values L, W and D can be selected within a range of +/- 40%, for example. The depth D of the tobacco article 12 is formed by a pair of parallel walls 13A, 13B, called hereinafter narrow walls 13A, 13B, and the width W of the tobacco article 12 is formed by a pair of parallel walls 14A, 14B, called hereinafter wide walls 14A, 14B. In some embodiments, the edges between the wide and narrow walls 13A, 13B, 14A, 14B can be rounded. According to other embodiments of the present disclosure, the tobacco article 12 can have any other suitable flat shape and/or external dimensions.

The tobacco article 12 comprises for example a tobacco portion 15 and a mouthpiece portion 16 arranged along the article axis X1. The tobacco portion 15 may for example be slightly longer than the mouthpiece portion 16. For example, the length L2 of the tobacco portion 15 according to the article axis X1 may be substantially equal to 17 mm. The width W2 of the tobacco portion 15 is substantially equal to the width W of the tobacco article 12. The length L3 of the mouthpiece portion 16 according to the article axis X1 may be substantially equal to 15 mm. As in the previous case, the values L2 and L3 can be selected within a range of +/- 40%, for example. The tobacco portion 15 defines an abutting end 18 of the article 12 and the mouthpiece portion 16 defines a mouth end 20 of the article 12. The tobacco portion 15 and the mouthpiece portion 16 may be fixed one to the other by a wrapper 21 extending around the article axis X1. The wrapper 21 forms the narrow and wide walls 13A, 13B, 14A, 14B of the tobacco article 12. In some embodiments, the wrapper 21 is formed from a same wrapping sheet. In some other embodiments, the wrapper 21 is formed by separate wrapping sheets wrapping separately the portions 15, 16 and fixed one to the other by any other suitable mean. The wrapper 21 may, for example, comprise paper and/or non-woven fabric and/or aluminium foil. The wrapper 21 may be porous or air impermeable and forms a plurality of airflow channels extending inside the article 12 between the abutting end 18 and the mouth end 20. The mouthpiece portion 16 may comprise a core 27 intended to act for example as a cooler to cool slightly the vapour before it is inhaled by the user. The core 27 may comprise for this purpose for example corrugated paper. The core 27 may be formed through an extrusion and/or rolling process into a stable shape. Advantageously, the core 27 is arranged inside the mouthpiece portion 16 to be entirely in contact with the internal surface of the wrapper 21 delimiting this mouthpiece portion 16. Additionally or alternatively, the core 27 acts as a filter.

The tobacco portion 15 comprises a vaporizable material and is intended to be heated by a heating chamber, as it will be explained in further detail below.

According to some examples, the tobacco article 12 consists of the tobacco portion 15. In particular, the tobacco article 12 may be devoid of a mouthpiece portion.

According to examples, with reference to Figure 9, at least one outer surface of the tobacco article 12, extending along the article axis X1 may present a plurality of grooves 28 forming air channels. The grooves 28 may form embossed air channels extending parallel to the article axis X1 . The grooves 28 may for example be formed on opposite faces of the tobacco portion 15, and have for example a constant width and/or depth along the article axis X1 . Each groove 28 may present in particular a width and/or depth being one or several dimensions larger than an average diameter of a tobacco item of the tobacco portion 15, wherein each tobacco item is for example formed by shredded tobacco, granulated tobacco, tobacco leaf and/or reconstituted tobacco.

In this case, the grooves 28 are not taken in account when determining the dimensions and the shape of the at least one cross section of the plurality of cross sections of the single inlet channel 56 which is substantially rectangular and presents a shape substantially equal to the tobacco cross section of the tobacco portion 15 adjacent to said at least one cross section. In other words, the substantial equality is appreciated in comparison with a tobacco cross section of a reference tobacco portion which would allow forming the grooved tobacco portion 15, by digging grooves 28 in at least one outer surface of the reference tobacco portion.

Referring again to Figure 1 , the aerosol generating device 11 comprises a device body 30 extending along a device longitudinal axis Y. The device body 30 comprises a mouthpiece 32 and a device housing 34, hereafter called housing 34, arranged successively along the device longitudinal axis Y. According to the example of Figure 1 , the mouthpiece 32 and the housing 34 form two different pieces. Particularly, according to this example, the mouthpiece 32 is designed to be fixed on or be received in an insertion opening formed at one of the ends of the housing 34. In this case, the tobacco article 12 can be inserted inside the device 1 1 when the mouthpiece 32 is removed from the housing 34. According to another example (not-shown), the mouthpiece 32 and the housing 34 form one single piece. In this case, the tobacco article 12 can be inserted inside the device 11 through for example a flow outlet. According to both examples, the mouthpiece 32 defines a through hole adapted to receive at least partially the tobacco article 12. Particularly, the through hole can be adapted to receive at least partially the mouthpiece portion 16 of the tobacco article 12. According to still another embodiment (not-shown), no mouthpiece 32 is provided with the aerosol generating device 11 . In this case, the mouthpiece portion 16 of the tobacco article 12 can form a mouth end designed to be in contact with the user’s lips and/or mouth while a vaping session.

The aerosol generating device 11 further comprises a flat-shaped heating chamber 38 extending along the device longitudinal axis Y between a proximal end 40 configured to receive at least the tobacco portion 15 of the flat-shaped tobacco article 12 and a distal end 42 opposite to the proximal end 40. The flat-shaped heating chamber 38 is in particular formed inside the housing 34. If the tobacco portion 15 is received in the heating chamber 38, the article axis X1 may extend in parallel, or be identical to, the device longitudinal axis Y. The proximal end 40 may for example open to the trough hole of the mouthpiece 32. The distal end 42 opens to a single inlet channel 56, described more in detail below.

The heating chamber 38 may comprise a heating zone adapted to heat the tobacco portion 15 of the tobacco article 12 when the tobacco article 12 is received in the heating chamber 38, in particular via the through hole of the mouthpiece 32 and the proximal end 40 of the heating chamber 38.

The heating chamber 38 has a flat shape. Particularly, as the tobacco article 12, the heating chamber 38 may also form a cuboid shape extending along the device longitudinal axis Y. For example, the heating chamber 38 may comprise a pair of parallel narrow walls extending along the device longitudinal axis Y, a pair of parallel wide walls extending also along the device longitudinal axis Y connecting the proximal end 40 with the distal end 42. The heating chamber 38 is in particular configured to receive the tobacco article 12 so that the corresponding wide walls 14A, 14B of the tobacco article 12 face the corresponding wide walls of the heating chamber 38, the corresponding narrow walls 13A, 13B of the tobacco article 12 face the corresponding narrow walls of the heating chamber 38, and the abutting end 18 of the tobacco article 12 faces the distal end 42.

The housing 34 delimits an internal space of the device 11 receiving various elements designed to carry out different functionalities of the device 1 1. This internal space can for example receive a battery 36 for powering the device 11 , the flat-shaped heating chamber 38, heater elements 39 for heating the heating chamber 38 and the tobacco article 12 received therein and a controller (not shown) for controlling the operation of the heating elements 39.

The housing 34 may present for example a flat-shaped cuboid extending along the device longitudinal axis Y. Referring to Figure 1 , the housing 34 may comprise a pair pf parallel narrow walls 44A, 44B and a pair of parallel wide walls 46A, 46B connecting edges of the narrow walls 44A, 44B. The narrow walls 44A, 44B and the wide walls 46A, 46B extend in particular in parallel to the device longitudinal axis Y. The housing 34 may further comprise a front end 48 configured to receive the mouthpiece 32 and a distal wall 50. The distal wall 50 may extend perpendicular to the device longitudinal axis Y and present an external surface 52. In particular, the distal wall 50 may form a rear end of the device 11 opposite to the front end 48. In some embodiments, the edges between the wide and narrow walls 44A, 44B, 46A, 46B can be rounded. In some embodiments, the edges between these walls 44A, 44B, 46A, 46B and the distal wall 50 and/or the front end 48 can be rounded.

With reference for example to Figures 3 and 4, the aerosol generating device 1 1 further comprises a rear portion 54 extending between the distal end 42 of the flat-shaped heating chamber 38 and the distal wall 50 of the housing 34.

The rear portion 54 defines one single inlet channel 56 configured to provide an airflow into the heating chamber 38. The single inlet channel 56 extends along the device longitudinal axis Y and presents a plurality of cross sections perpendicular to the device longitudinal axis Y. At least one cross section of the plurality of cross sections is substantially rectangular. The at least one cross section presents a shape substantially equal, preferably exactly equal, to a tobacco cross section of the tobacco portion 15 adjacent to this at least one cross section. The tobacco cross section is thus in particular arranged adjacent to the single inlet channel 56 and/or may form a distal end of the tobacco portion 15.

In particular, the single inlet channel 56 may be delimited, along the device longitudinal axis Y, by a channel inlet cross section defining an airflow inlet and by a channel outlet cross section. The channel inlet cross section may extend according to the distal wall 50, in particular may extend in the same plane as the external surface 52 of the distal wall 50. The channel outlet cross section may delimit the single inlet channel 56 at an end opposite to the channel inlet cross section. In particular, the channel outlet cross section may be adjacent to the heating chamber 38. The channel outlet cross section of the single inlet channel 56 may present a substantially rectangular shape. Preferably, an area defined by the channel outlet cross section matches and/or covers completely an area defined by the tobacco cross section. Preferably, as for example illustrated in Figures 3 to 5, according to the first embodiment, each cross section of the plurality of cross sections of the single inlet channel 56, including in particular the channel inlet cross section and the channel outlet cross section, may be substantially rectangular. For example, each cross section may present the same area.

The single inlet channel 56 may be delimited, according to directions perpendicular to the device longitudinal axis Y, by at least one inner surface 58 connecting the channel inlet cross section to the channel outlet cross section. For example, the inner surface 58 may be formed by four inner walls in the case of the rectangular cross sections of the single inlet channel 56. Preferably, the inner surface 58 may form at each point an angle with the device longitudinal axis Y less than 90°. For example, the inner surface 58 may extend in parallel to the device longitudinal axis Y, i.e. form an angle equal to 0° with the axis Y. For example, the inner surface 58 may present a smooth transition between the channel inlet cross section and the channel outlet cross section. In other words, for example, the inner surface 58 is deprived of steps.

For example, the single inlet channel 56 may present, non-illustrated in the Figures, a rounded transition with the external surface 52 of the distal wall 50. In particular, the external surface 52 may blend into the inner surface 58 via a curved or rounded transition portion.

According to examples, the single inlet channel 56 presents, according to the device longitudinal axis Y, a length greater than a length of the heating chamber 38. For example, a distance, according to the device longitudinal axis Y, between the distal wall 50 of the device housing 34 and the distal end 42 of the flat-shaped heating chamber 38 defines a channel length. The channel length is in particular equal to a length of the rear portion 54. The channel length may be longer than a heating chamber length corresponding to a distance between the proximal end 40 and the distal end 42 according to the device longitudinal axis Y.

Figure 9 illustrates an example of an area A of enhanced airflow according to the Coanda effect in the heating chamber 38, obtained thanks to shape of the single inlet channel 56. In particular, upon operation of the device 1 1 , the airflow inside the flat-shaped heating chamber 38 sticks to the walls of the heating chamber 38 thanks to the shape and/or length of the single inlet channel 56.

SECOND EMBODIMENT

A second embodiment of the aerosol generating assembly 10 is now described with reference to Figures 6 to 8. The aerosol generating assembly 10 according to the second embodiment comprises at least some, preferably all, features of the first embodiment, except the differences described below. The same or corresponding elements are not described again. The same reference signs are used for the same or corresponding elements. For example, the tobacco article 12 of the second embodiment may be identical to the first embodiment.

Contrary to the first embodiment, the channel inlet cross section may present a shape different from a rectangular shape, such as a circular shape or an elliptic shape. For example, a circular shape of the channel inlet cross section is illustrated in Figure 8, which is a rear view of the aerosol generating device 11 , i.e. a view along the device longitudinal axis Y. According to some examples, the single inlet channel 56 blends or fades from the shape of the channel inlet cross section, such as the circular shape, to the shape of the channel outlet cross section, such as the rectangular shape. According to examples, the inner surface 58 connecting the channel inlet cross section to the channel outlet cross section, may form at each point an angle with the device longitudinal axis Y strictly less than 90°. For example, the inner surface 58 may present a smooth transition between the channel inlet cross section and the channel outlet cross section. In particular, the inner surface 58 may define at least one straight line 60, for example four straight lines 60, connecting a corresponding edge of the substantially rectangular shape of the channel outlet cross section with the channel inlet cross section. Such straight line 60 of the inner surface 58 is for example illustrated in Figure 7.

Preferably, a maximum width of the single inlet channel 56 at the channel inlet cross section, such as a radius in case of a circular cross section, is smaller than a maximum width of the single inlet channel 56 at the channel outlet cross section, such as a transversal width of the rectangular shape of the channel outlet cross section. Each maximum width is defined along to a direction perpendicular to the device longitudinal axis Y.

According to examples, any feature(s) of the housing 34 according to the first embodiment may be combined with the single inlet channel 56 according to the second embodiment.

Claims

1 . An aerosol generating device (11 ) configured to operate with a flat-shaped tobacco article (12) and comprising a flat-shaped heating chamber (38) extending along a device longitudinal axis (Y) between a proximal end (40) configured to receive at least a tobacco portion (15) of the flat-shaped tobacco article (12) and a distal end (42) opposite to the proximal end (40); wherein the aerosol generating device (11 ) comprises a rear portion (54) extending between the distal end (42) of the flat-shaped heating chamber (38) and a distal wall (50) of a device housing (34), the rear portion (54) defining one single inlet channel (56) configured to provide an airflow into the heating chamber (38); the single inlet channel (56) extending along the device longitudinal axis (Y) and presenting a plurality of cross sections perpendicular to the device longitudinal axis (Y), wherein at least one cross section of the plurality of cross sections is substantially rectangular and presents a shape substantially equal to a tobacco cross section of the tobacco portion (15) adjacent to said at least one cross section.

2. The aerosol generating device (1 1 ) according to claim 1 , wherein the single inlet channel (56) is delimited, along the device longitudinal axis (Y), by a channel inlet cross section defining an airflow inlet and by a channel outlet cross section adjacent to the heating chamber (38), wherein the channel outlet cross section presents a substantially rectangular shape.

3. The aerosol generating device (1 1 ) according to claim 2, wherein the single inlet channel (56) is delimited, according to directions perpendicular to the device longitudinal axis (Y), by at least one inner surface (58), the inner surface (58) connecting the channel inlet cross section to the channel outlet cross section, wherein the inner surface (58) forms at each point an angle with the device longitudinal axis (Y) less than 90°.

4. The aerosol generating device (11 ) according to claim 3, wherein the inner surface (58) presents a smooth transition between the channel inlet cross section and the channel outlet cross section.

5. The aerosol generating device (1 1 ) according to claim 3 or 4, wherein the at least one inner surface (58) defines at least one straight line (60) connecting an edge of the substantially rectangular shape of the channel outlet cross section with the channel inlet cross section.

6. The aerosol generating device (1 1 ) according to any of claims 2 to 5, wherein a maximum width of the single inlet channel (56) at the channel inlet cross section is smaller than a maximum width of the single inlet channel (56) at the channel outlet cross section, each maximum width being defined along to a direction perpendicular to the device longitudinal axis (Y).

7. The aerosol generating device (1 1 ) according to any of claims 2 to 6, wherein the channel inlet cross section presents a shape different from a rectangular shape.

8. The aerosol generating device (11 ) according to claim 7, wherein the channel inlet cross section presents a circular shape or an elliptic shape.

9. The aerosol generating device (11 ) according to any one of claims 1 to 6, wherein each cross section of the plurality of cross sections is substantially rectangular.

10. The aerosol generating device (1 1 ) according to any of the preceding claims, wherein the single inlet channel (56) presents a rounded transition with an external surface (52) of the distal wall (50) of the device housing (34).

1 1. The aerosol generating device (1 1 ) according to any of the preceding claims, wherein a distance, according to the device longitudinal axis (Y), between the distal wall (50) of the device housing (34) and the distal end (42) of the flat-shaped heating chamber (38) defines a channel length, wherein the channel length is longer than a heating chamber length corresponding to a distance between the proximal end (40) and the distal end (42) according to the device longitudinal axis (Y).

12. The aerosol generating device (1 1 ) according to any of the preceding claims, wherein an area defined by the at least one cross section matches and/or covers completely an area defined by the tobacco cross section.

13. The aerosol generating device (1 1 ) according to any of the preceding claims, wherein at least one outer surface of the tobacco article (12) extending along an article axis presents a plurality of grooves (28) forming air channels.

14. An aerosol generating assembly (10) comprising the aerosol generating device (11) according to any of the preceding claims, further comprising the flat-shaped tobacco article (12) having the tobacco portion (15) received in the flat-shaped heating chamber