Aerosol Generating Device with Optimized Air Inlet Arrangement

Abstract

The present invention concerns an aerosol generating device configured to operate with a consumable article comprising a substrate portion. The device comprises a heating chamber extending along a chamber axis, configured to receive at least the substrate portion and comprising a plurality of contact walls designed to be in contact with an external surface of the substrate portion. The plurality of contact walls comprises a bottom wall and at least one lateral wall. The heating chamber further comprises an inlet portion comprising an inlet hole of an airflow path extending through the substrate portion. Said inlet portion extends on the bottom wall and/or on the or at least one lateral wall to create an airflow gradient at least at a region of the heating chamber adjacent to this inlet portion.

Description

FIELD OF THE INVENTION

The present invention concerns an aerosol generating device with optimized air inlet arrangement.

The aerosol generating device according to the invention is configured to operate with a consumable article comprising for example a solid substrate, also known as aerosol forming 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 an aerosol generating device known as a heat-not-burn device. Devices of this type generate aerosol or vapour by heating an aerosol forming substrate (usually a solid 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 by-products 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.

Regardless of the heating method used to heat a solid substrate, great care is taken to ensure even heating of the substrate. Particularly, it is known that if a tobacco containing substrate is heated too much, harmful chemicals may develop. If the temperature is too low, flavour and aerosol quantity are too low, hence reducing user experience. It is thus important to evenly heat the tobacco containing substrate at just the right temperature.

According to the prior art, this has been primarily achieved by focusing on the design of the heating element as well as the heating profile used to heat the substrate. This can be complicated and not optimal. For example, in the prevailing tobacco stick consumables, air is drawn in the bottom of the stick, even though this may not be the optimal design.

SUMMARY OF THE INVENTION

One of the aims of the invention is to provide an aerosol generating device allowing evenly heating of a solid substrate without using complex design of the heating element or special heating profiles.

For this purpose, the invention relates to an aerosol generating device configured to operate with a consumable article comprising a substrate portion containing a solid substrate and defining an external surface;

• • the aerosol generating device comprising a heating chamber extending along a chamber axis and configured to receive at least the substrate portion of the consumable article;
  • the heating chamber comprising a plurality of contact walls designed to be in contact with the external surface of the substrate portion of the consumable article, the plurality of contact walls comprising a bottom wall arranged substantially perpendicularly to the chamber axis and at least one lateral wall arranged substantially parallel to the chamber axis, the bottom wall being in contact with the or each lateral wall along a common border;
  • the heating chamber further comprising a heating element extending from a centre of the bottom wall parallel to the or at least one lateral wall;
  • the heating chamber further comprising an inlet portion comprising an inlet hole of an airflow path extending through the substrate portion of the consumable article when it is received in the heating chamber and when the device is operated to generate aerosol;
  • said inlet portion extending on the bottom wall and/or on the or at least one lateral wall to create an airflow gradient at least at a region of the heating chamber adjacent to this inlet portion, said airflow gradient extending from the centre of the bottom wall until the common border.

Particularly, it was observed that in case of a single air inlet arranged in traditional aerosol generating devices in a centre bottom portion of the heating chamber, a cool zone is formed in the substrate portion of the consumable article near the corresponding inlet since the total quantity of fresh air passes through this zone. In this cool zone, the tobacco remains unconsumed. On the contrary, in a top portion of the substrate portion or in a portion immediately adjacent to a heating element, an overheated zone is usually formed. In this overheated zone, the tobacco may be burnt. Creating an airflow gradient toward the common border (i.e. a greater airflow in the periphery region of the substrate in comparison with its central region) makes it possible to counter this effect. Thus, cooling effect in the centre bottom portion of the substrate portion is reduced and heat may be more evenly distributed throughout this substrate portion.

According to some embodiments, said inlet portion extends:

• • on the bottom wall, according to each transversal direction perpendicular to the chamber axis and passing through a centre of the bottom wall, from the common border until ⅜, preferably ¼, of the total length of the bottom wall according to this direction; or
  • on the or at least one lateral wall, according to the chamber axis, preferably from the common border until ⅔ of the total length of this lateral wall according to this axis.

Arranging an air inlet portion close to a common border of the bottom and lateral walls of the heating chamber forces air entering in the periphery region of the substrate. Thus, an airflow gradient is created between the periphery and central regions.

According to some embodiments, said inlet portion comprises a plurality of inlet holes.

Thanks to these features, air can enter through several air inlets holes. Thus, contrary to a single air inlet case, only a part of the fresh air can pass through the corresponding inlet zone. This reduce cooling effect in the inlet zone.

According to some embodiments, the inlet portion extends on the bottom wall.

According to some embodiments, the concentration and/or the dimensions of the inlet holes increase(s) from the centre of the bottom wall to the common border.

Thanks to these features, a greater airflow is created in the periphery region of the substrate. Thus, an airflow gradient is created between the periphery and central regions

According to some embodiments, the inlet portion extends on the bottom wall.

According to some embodiments, the inlet holes are arranged symmetrically in respect with the centre of the bottom wall.

According to some embodiments, the inlet portion extends on the or at least one lateral wall.

According to some embodiments, at least two inlet holes are arranged according to the chamber axis, preferably homogeneously according to the chamber axis.

Thanks to these features, a better heat distribution inside the substrate portion of consumable article can be achieved.

According to some embodiments, the inlet portion extends on a unique lateral wall forming a cylindrical wall.

According to some embodiments, at least two inlet holes are arranged to face each other.

According to some embodiments, a plurality of inlet holes are arranged circumferentially on said cylindrical wall.

Thanks to these features, inlet holes can be arranged symmetrically in respect with a central axis passing through the device. This ensures more homogeneous heat distribution inside the substrate portion of the consumable article.

According to some embodiments, the substrate portion of the consumable article is wrapped in a wrapper, the wrapper comprising a plurality of openings;

• • the inlet hole of the inlet portion being arranged to face said openings.

Thanks to these features, air can enter from the corresponding air inlet holes of the device directly inside the substrate portion of the consumable article, without passing through the wrapper. This ensures a better airflow throughout the consumable article and consequently, better aerosol generation.

According to some embodiments, the heating chamber comprises several inlet portions.

According to some embodiments, at least one inlet portion extends on the bottom wall and at least one inlet portion extends on the or at least one lateral wall.

Thanks to these features, inlet holes can be arranged on both bottom and at least one lateral walls. This can further improve heat transfer inside the substrate portion of consumable article.

According to some embodiments, the heating chamber further defines an open end opposite to the bottom wall.

Thanks to these features, the consumable article can be inserted at least partially in the heating chamber.

According to some embodiments, the or each inlet portion forms a unique air permeable portion on the corresponding contact wall.

Thanks to these features, the airflow inside the consumable article can be better controlled and predicted.

According to some embodiments, the or at least one inlet hole is arranged adjacent to the common border.

Thanks to these features, it is possible to achieve a more even air distribution inside the substrate portion of the consumable article.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 is a cross-sectional schematic view of an aerosol generating device according to the invention, the aerosol generating device receiving a consumable article;

FIG. 2 is a detailed view of a bottom wall of a heating chamber of the aerosol generating device of FIG. 1, according to a first embodiment of the invention;

FIG. 3 is a detailed view of the heating chamber of the aerosol generating device of FIG. 1, according to a second embodiment of the invention;

FIG. 4 is a view similar to the view of FIG. 3, the heating chamber being according to a third embodiment of the invention; and

FIG. 5 is a view similar to the view of FIG. 3, the heating chamber being according to a fourth embodiment of the invention.

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 “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 heating 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 forming substrate” or “substrate” may refer to a material which may for example comprise nicotine or tobacco or any other smokable material, 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 former 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.

As used herein, the term “aerosol” may include a suspension of aerosol forming substrate 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 aerosol forming substrate.

An aerosol generating device 10 according to the invention is shown on FIG. 1. This aerosol generating device 10 is designed to operate with a consumable article 12 also shown on this Figure.

Particularly, as it is shown on FIG. 1, the consumable article 12 comprises a substrate portion 14 and a filter portion 16. Both portions 14, 16 can be wrapped using a unique wrapper 18 attaching these portions together. In other examples, the portions 14, 16 may be wrapped by different wrappers and fixed one to the other by any other suitable mean. The or each wrapper 18 may, for example, comprise paper and/or non-woven fabric and/or aluminium. The or each wrapper 18 may be porous or air impermeable. Advantageously, according to the embodiments explained below, the or each wrapper 18 is air impermeable. Additionally, according to these embodiments, the or each wrapper 18 wraps the corresponding portions 14, 16 only circumferentially. This means that the corresponding ends of the portions 14, 16 can be unwrapped. The consumable article 12 can have a generally tubular shape defining for example a circular or elliptical cross-section. According to another example, the consumable article 12 defines a rectangular cross-section.

The substrate portion 14 contains an aerosol forming substrate intended to be heated by a heating chamber of the aerosol generating device 10 as it will be explained in further detail below. According to the invention, the aerosol forming substrate comprises a solid substrate. As mentioned above, the solid substrate can comprise shredded tobacco. The shredded tobacco can be advantageously substantially aligned along the direction of extension of the consumable article 12. Additionally, according to some examples, the substrate portion 14 may comprise one or several susceptors integrated into the aerosol forming substrate. The susceptors may be formed from electrical conductor materials able to generate eddy currents when placed within a magnetic field. Eddy currents cause the susceptors to generate heat suitable for heating the aerosol forming substrate to generate aerosol. The magnetic field can be generated by a coil comprised in a heating system of the aerosol generating device 10. The substrate portion 14 may comprise two or more adjacent segments with at least an upstream segment containing an aerosol forming substrate and a downstream segment forming spacer or cooling segment. The downstream segment can be a tube, for example, made of paper or other rigid material such as PLA material. The tube may be hollow or partially filled or reinforced by internal, e.g. radial and/or longitudinal, walls.

The filter portion 16 comprises a core acting for example like a filter. The core may for example be a foam, or packed strands or fibres. In some examples, the filter portion 16 can form a mouthpiece intended to be in contact with the user's lips and/or mouth while using the device 10. In some other examples, the filter portion 16 can be inserted into a separate mouthpiece intended to be in contact with the user's lips and/or mouth. According to some other examples, the consumable article 12 can comprise only the substrate portion 14.

The aerosol generating device 10 comprises a housing 20 defining an insertion opening 21 suitable for insertion of the consumable article 12. The housing 20 delimits an internal space of the device 10 receiving various elements designed to carry out different functionalities of the device 10. This internal space can for example receive a battery 23 for powering the device 10, a control module 24 for controlling the operation of the device 10, and a heating chamber 25 configured to receive and heat at least a part of the consumable article 12. Among these elements, only the heating chamber 25 will be explained in further detail. The other elements, as for example the battery 23 and the control module 24, can be implemented using known techniques.

The heating chamber 25 extends along a chamber axis X between a closed end 30 and an open end 31, and has substantially the same cross-sectional shape as the consumable article 12. The open end 31 opens to the insertion opening 21 of the housing 20. As it is shown on FIG. 1, the heating chamber 25 is adapted to receive the substrate portion 14 of the consumable article 12 through the open end 31 so as this substrate portion 14 extends inside the heating chamber 25 along the chamber axis X. Additionally, as mentioned above, the heating chamber 25 is adapted to heat at least a part of the substrate portion 14.

For this purpose, the heating chamber 25 comprises a heating element 34 which is formed in the example of FIG. 1 by a heating blade. Such a heating blade is configured to penetrate inside the substrate portion 14 of the consumable article 12 while its insertion. The operation of the heating element 34 may be controlled by the control module 24 using control methods known per se.

The heating chamber 25 comprises a plurality of contact walls designed to be in contact with an external surface of the substrate portion 14 of the consumable article 12. In the example of FIG. 1, this external surface is formed by the part of the wrapper 18 received in the heating chamber 25 and the unwrapped end of the substrate portion 14. The contact walls comprises a bottom wall 40 arranged substantially perpendicularly to the chamber axis X and at least one lateral wall 41 arranged substantially parallel to the chamber axis X. The bottom wall 40 is in contact with the or each lateral wall 41 along a common border 42 and defines a centre C. The heating element 34 extends from the centre C according to the chamber axis X. The centre C of the bottom wall 40 is defined as a geometrical centre of this wall which can be determined according to the shape of the bottom wall 40. For example, when the bottom wall 40 has a circular shape, the centre C is the centre of the circle forming this shape. When the bottom wall 40 has a rectangular shape, the centre C is the intersection point of its diagonals. When the bottom wall 40 has a more complicated shape, the centre C can be defined as the centre of mass of the corresponding shape.

In the example of FIG. 1, the heating chamber 25 defines generally tubular shape having for example a circular cross-section. In this, case a single lateral wall 41 is arranged parallel to the chamber axis X. Additionally, in the example of FIG. 1, the lateral wall 41 of the heating chamber 25 is in contact with the wrapper 18 whereas the bottom wall 40 is in contact with the unwrapped end of the substrate portion 14.

According to the invention, the heating chamber 25 further comprises an inlet portion comprising at least one inlet hole making it possible air entering inside the substrate portion 14 of the consumable article 12. The or each inlet hole is in fluid communication with one or several air inlets arranged for example in the housing 20 of the device 10. Thus, at least one airflow path is formed inside the housing 20 and extends through the substrate portion 14 of the consumable article 12 when it is received in the heating chamber 25 and when the device 10 is operated to generate aerosol. According to different embodiments of the invention explained in further detail below, the inlet portion extends on the bottom wall 40 and/or on the or at least one lateral wall 41 to create an airflow gradient at least at a region of the heating chamber 35 adjacent to this inlet portion. The airflow gradient extends from the centre C of the bottom wall 40 until the common border 42.

Particularly, by “airflow gradient”, it is understood a change of airflow (i.e. airflow rate) between at least two different points of the substrate portion 14 when it is received in the heating chamber 25 and the device 10 is operated to generate aerosol. According to the invention, such an airflow gradient extends from the centre C of the bottom wall 40 until the common border 42 which means that a greater airflow is generated in regions adjacent to the or at least one lateral wall 41 than an airflow generated in regions adjacent to the heating element 34. In order to achieve such a gradient, several embodiments are possible.

A detailed view of the bottom wall 40 according to the first embodiment of the invention is shown on FIG. 2.

Particularly, according to the first embodiment of the invention, the heating chamber 25 comprises an inlet portion 45 which extends on the whole bottom wall 40 of the heating chamber 25 and defines a plurality of inlet holes. In order to ensure an airflow gradient extending from the centre C until the common border 42, the concentration and/or the dimensions of the inlet holes increase from the centre C of the bottom wall 40 to the common border 42. The holes can be arranged for example symmetrically in respect with the centre C.

In the example of FIG. 2, the bottom wall 40 has a circular shape. In the examples A), D), and G) of this Figure, the holes formed in the inlet portion 45 has a circular shape with a diameter increasing from the centre C until the common border 42. In the example C) of this Figure, the circular holes have a same diameter but their number is greater near the common border 42 than near the centre C. In the examples B) and E) of this Figure, the holes extend according to several circumferential directions and are comprised within one or several arcs. Thus, their area increases from the centre C to the common border 42. Finally, in the example F) of this Figure, the holes have a rectangular shape oriented toward the centre C. Of course, other hole arrangements and/or shapes can be applied.

A detailed view of a part of the heating chamber 25 according to the second embodiment of the invention is shown on FIG. 3.

Particularly, according to the second embodiment of the invention, the heating chamber 25 comprises an inlet portion which extends on the bottom wall 40 according to each transversal direction Y perpendicular to the chamber axis X and passing through the centre C of the bottom wall 40, from the common border 42 until ¼ of the total length L1 of the bottom wall 40 according to this direction Y. Additionally, the length L1 of the bottom wall 41 according to a transversal direction Y passing through the centre C is measured along its surface which is in contact with the external surface of the consumable article 12. In other words, this length L1 does not include the eventual thickness of one or several lateral walls 41. In the example of FIG. 3, the length L1 is measured between the internal surfaces of the lateral wall 41 which are intended to be in contact with the wrapper 18 of the consumable article 12. It is also clear that when the bottom wall 40 has a circular shape, the length L1 according to each transversal direction Y presents the same value.

According to the example of FIG. 3, a circumferential inlet portion 50 adjacent to the common border 42 is formed around the heating element 34. When the bottom wall 40 presents a non-circular shape, the inlet portion 50 is defined as a peripheral zone adjacent to the common border 42 and extending according to each transversal direction Y passing through the centre C until ¼ of the total length L1 of the bottom wall 40 according to this direction Y. For example, the inlet portion 50 can be symmetric in respect with the centre C of the bottom wall 42.

The inlet portion 50 comprises at least one inlet hole making it possible air entering inside the substrate portion 14 of the consumable article 12. The or each inlet hole is in fluid communication with one or several air inlets arranged for example in the housing 20 of the device 10. Thus, at least one airflow path is formed inside the housing 20. When the substrate portion 14 is received in the heating chamber 25, the or each airflow path extends through this substrate portion 14 and through the filter portion 16 of the consumable article 12 until the non-wrapped end of the filter portion 16. Several airflow paths inside the substrate portion 14 are shown in the example of FIG. 3. Advantageously, according to the invention, said inlet hole(s) is(are) the unique opening(s) formed in the walls of the heating chamber 25.

In the example of FIG. 3, the inlet portion 50 comprises two triplets of inlet holes 52A, 52B arranged for example on either side of the heating element 34 according to the same transversal direction Y. In each triplet, the inlet holes can for example be homogeneously along said transversal direction Y. According to another example, the inlet portion 50 can comprise for example only one inlet hole which can have a greater diameter than the inlet holes of the triplets 52A, 52B. According to still another example, the inlet portion 50 can define a plurality of inlet holes arranged according to one or several circumferential directions. Along the corresponding circumferential direction, the inlet holes can for example be arranged homogeneously. According to still another example, the inlet portion 50 can define a plurality of inlet holes arranged symmetrically in respect with the centre C of the bottom wall 40. According to still another example, one or several inlet holes can be arranged adjacent to the common border 42. According to still another example, the second embodiment can be combined with the first embodiment. Particularly, in this case, the inlet portion 50 as defined in relation with the second embodiment, can comprise a plurality of holes those dimensions and/or concentration increase(s) from an internal border surrounding the centre C to the common border 42. In this case, the holes can be formed/arranged as shown in the examples of FIG. 2 where a central region is excluded from the corresponding inlet portion. Of course, other examples of inlet holes arrangement and their number are still possible.

Additionally, it is clear that when the inlet holes are formed in the bottom wall 40 of the heating chamber 25 and the corresponding end of the substrate portion 14 is unwrapped, no additional opening is necessary on the wrapper 18. In some cases, the wrapper 18 may comprise openings which may be closed by the lateral wall 41 of the heating chamber 25 when the substrate portion 14 is inserted therein.

FIG. 4 shows an example of the heating chamber 25 according to the third embodiment of the invention.

Particularly, according to the third embodiment of the invention, the heating chamber 25 comprises at least one inlet portion which extends on the or at least one lateral wall 41, according to the chamber axis X, from the common border 42 until ⅔ of the total length L2 of this lateral wall according to this axis X. As in the previous case, the length L2 of the or at least one lateral wall is measured along to its surface which is in contact with the external surface of the consumable article 12. In other words, in the example of FIG. 4, the length L2 is measured along the chamber axis X between the bottom wall 40 and the open end 31 of the heating chamber 25.

In the example of FIG. 4, an inlet portion 60 is formed circumferentially on the lateral wall 41 to be adjacent to the common border 42. As mentioned above, this inlet portion 60 extends from the common border 42 along the chamber axis X according to ⅔ of the length L2 of the lateral wall 41 according to this axis X.

As in the previous embodiment, the inlet portion 60 forms at least one inlet hole which is in fluid communication with one or several air inlets arranged in the housing 20 of the device 10. Thus, one or several airflow paths are formed inside the housing 20 and extend then through the substrate portion 14 and the filter portion 16 of the consumable article 12 until the non-wrapped end of the filter portion 16. These paths inside the substrate portion 14 are shown on FIG. 4.

In the example of FIG. 4, the inlet portion 60 comprises two triplets of inlet holes 62A, 62B. The triplets 62A, 62B can for example be arranged to face each other. In each triplet 62A, 62B, the inlet holes can be arranged homogenously according to the chamber X. Additionally, at least two inlet holes of different triplets 62A, 62B can be arranged according to the same transversal direction Y. According to another example, the inlet portion 60 can comprise for example only one inlet hole which can have a greater diameter than the inlet holes of the triplets 62A, 62B. According to still another example, the inlet portion 60 can define a plurality of inlet holes arranged according to one or several circumferential directions extending through the lateral wall 41. Along the corresponding circumferential direction, the inlet holes can for example be arranged homogeneously. According to still another example, the inlet portion 60 can define a plurality of inlet holes arranged symmetrically in respect with a centre axis passing though the centre C of the bottom wall 40 parallel to the chamber axis X. According to still another example, one or several inlet holes can be arranged adjacent to the common border 42. Of course, other examples of inlet holes arrangement and their number are still possible.

Additionally, in the example of FIG. 4, the heating element 34 extends from the centre C of the bottom wall 40 and no inlet hole 40 is formed in this wall. However, in a general case, at least one inlet hole may be formed in the bottom wall 40. For example, when the heating is performed by an element other than the heating blade 34, an inlet hole may be formed at the centre C of the bottom wall 40.

According to the third embodiment of the invention, the wrapper 18 of the consumable article 12 forms advantageously an opening facing each inlet hole. In this case, the wrapper 18 can comprise a label or any other key element indicating to the user the right insertion orientation of the consumable article 12 in the heating chamber 25. According to another example, the wrapper 18 can be formed at least partially from an air permeable material.

FIG. 5 shows the heating chamber 25 according to the fourth embodiment of the invention. This embodiment corresponds to a combination of the previous two embodiments and in some cases, of all of the three previous embodiments.

Particularly, according to the fourth embodiment, an inlet portion is formed on the bottom wall 40 and an inlet portion is formed on at least one lateral wall 41 of the heating chamber 25. Each of these inlet portions is similar to the respective inlet portion explained above. Thus, the inlet portion formed on the bottom wall 40 extends on this wall 40 according to each transversal direction Y perpendicular to the chamber axis X and passing through a centre C of the bottom wall 40, from the common border 42 until ¼ of the total length L1 of the bottom wall 40 according to this direction Y. Similarly, the inlet portion formed on at least one lateral wall 41 extends on this lateral wall 41, according to the chamber axis X, from the common border 42 until ⅔ of the total length L2 of this lateral wall according to this axis X.

In the example of FIG. 5, an inlet portion 50 is formed on the bottom wall 40 and an inlet portion 60 is formed one the lateral wall 41.

Additionally, as in the previous cases, each inlet portion 50, 60 comprises at least one inlet hole similar to the inlet holes explained above. For example, as shown on FIG. 5, the inlet portion 50 of the bottom wall 40 can form two inlet holes arranged according the same transversal direction Y and the inlet portion 60 can form two triplets of inlet holes facing each other. These inlet holes form several airflow paths inside the substrate portion 14 as shown on FIG. 5.

According to another embodiment (not shown), the third embodiment is combined with the first embodiment to form a bottom wall 42 as shown in one the examples of FIG. 2 and a lateral wall 41 as shown on FIG. 4.

Claims

1. An aerosol generating device configured to operate with a consumable article comprising a substrate portion containing a solid substrate and defining an external surface;

the aerosol generating device comprising a heating chamber extending along a chamber axis and configured to receive at least the substrate portion of the consumable article;

the heating chamber comprising a plurality of contact walls designed to be in contact with the external surface of the substrate portion of the consumable article, the plurality of contact walls comprising a bottom wall arranged substantially perpendicularly to the chamber axis and at least one lateral wall arranged substantially parallel to the chamber axis, the bottom wall being in contact with the or each lateral wall along a common border;

the heating chamber further comprising a heating element extending from a centre of the bottom wall parallel to the or at least one lateral wall;

the heating chamber further comprising an inlet portion comprising an inlet hole configured to be in communication with an airflow path extending through the substrate portion of the consumable article when the substrate portion is received in the heating chamber and when the device is operated to generate aerosol;

said inlet portion extending on the bottom wall and/or on the or at least one lateral wall to create an airflow gradient at least at a region of the heating chamber adjacent to the inlet portion, said airflow gradient extending from the centre of the bottom wall to the common border.

2. The aerosol generating device according to claim 1, wherein said inlet portion extends:

on the bottom wall, according to each transversal direction perpendicular to the chamber axis and passing through a centre of the bottom wall, from the common border to at least ⅜, a total length of the bottom wall in the transversal direction; or

on the or at least one lateral wall, according to the chamber axis, from the common border to at least ⅔ of the total length of the or at least one lateral lateral wall according to the chamber axis.

3. The aerosol generating device according to claim 1, wherein said inlet portion comprises a plurality of inlet holes.

4. The aerosol generating device according to claim 3, wherein:

the inlet portion extends on the bottom wall; and

concentration and/or dimensions of the inlet holes increases from the centre of the bottom wall to the common border.

5. The aerosol generating device according to claim 3, wherein:

the inlet portion extends on the bottom wall; and

the inlet holes are arranged symmetrically with respect with the centre (C) of the bottom wall.

6. The aerosol generating device according to claim 3, wherein:

the inlet portion extends on the or at least one lateral wall; and

at least two inlet holes are arranged according to the chamber axis, and homogeneously according to the chamber axis.

7. The aerosol generating device according to claim 6, wherein the inlet portion extends on a unique lateral wall forming a cylindrical wall.

8. The aerosol generating device according to claim 7, wherein at least two inlet holes are arranged to face each other.

9. The aerosol generating device according to claim 7, wherein a plurality of inlet holes is arranged circumferentially on said cylindrical wall.

10. The aerosol generating device to claim 6, wherein the substrate portion of the consumable article is wrapped in a wrapper, the wrapper comprising a plurality of openings; and

the inlet holes of the inlet portion being arranged to face said openings.

11. The aerosol generating device according to claim 1, wherein the heating chamber comprises a plurality of inlet portions.

12. The aerosol generating device according to claim 11, wherein at least one inlet portion extends on the bottom wall and at least one inlet portion extends on the or at least one lateral wall.

13. The aerosol generating device according to claim 1, wherein the heating chamber further defines an open end opposite to the bottom wall.

14. The aerosol generating device according to claim 1, wherein the or each inlet portion forms a unique air permeable portion on the corresponding contact wall.

15. The aerosol generating device according to claim 1, wherein the or at least one inlet hole is arranged adjacent to the common border.