Aerosol generating device comprising two heating elements

FIELD OF THE INVENTION

The present invention concerns an aerosol generating device comprising two heating elements.

The aerosol generating device according to the invention is configured to operate with an aerosol generating substrate which presents 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, also known as aerosol generating 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.

Heating of the aerosol generating substrate is usually carried out by a heating system integrated within the device. Particularly, in some aerosol generating devices, the heating 2 system provided with a heating chamber is able to receive and heat the substrate by heat transfer. However, in some cases, the heat transfer is not optimal. This can lead to an inhomogeneous heating of the substrate and deteriorate its aerosol forming capacities. In this case, the substrate is not used efficiently and at least some parts of it may be wasted. Additionally, it can deteriorate or modify the taste of the aerosol that is expected by the user.

SUMMARY OF THE INVENTION

One of the aims of the invention is to provide an aerosol generating device which ensures an efficient heating of an aerosol generating substrate.

For this purpose, the invention relates to an aerosol generating device configured to operate with an aerosol generating substrate and comprising:

- a device body extending along a device axis;

- a cup-shaped heating chamber defining an open end and at least two heating walls, the heating chamber being configured to receive a heater part of the aerosol generating substrate through the open end;

- two heating elements, each heating element being adjacent to a respective heating wall of the heating chamber;

- a controller configured to operate separately each heating element with the same aerosol generating substrate, according to a heating profile chosen among a predetermined group of heating profiles.

By heating using at least two heating walls of the heating chamber, it is possible to improve heat transfer to the substrate. The substrate can notably be heated homogeneously and without heat loss. Additionally, the controller can choose an optimal heating profile for each operation state of the device. Such heating profile may comprise activating of both heaters or only one of them. Different heating profiles can be carried out by the controller at different instants of the vaping session and may be repeated with different frequencies and depending on different external/internal conditions. Additionally, a heating profile can be chosen be the controller basing on at least one parameter like for example the temperature of at least one heater or of the substrate or of the aerosol.

According to some embodiments, said group of heating profiles comprises at least:

- a first heating profile comprising activation of both heating elements until reaching a first target temperature; 3

- a second heating profile comprising activation of one of the heating elements until reaching a second target temperature.

Thanks to these features, the heating elements can be operated simultaneously or separately. For example, the heating elements can be operated simultaneously when it is necessary to increase rapidly the substrate temperature. Only one of the heaters may be operated when it is necessary to maintain the substrate temperature substantially unchanged.

According to some embodiments, the controller is configured to choose the first heating profile during a pre-heating mode of operation of the device and the second heating profile during a floating mode of operation of the device.

Thanks to these features, it is possible to render operable the aerosol generating device to generate aerosol after it has been switched, in a very fast way. Additionally, when it is no more necessary to heat strongly the substrate, as for example during the floating mode of operation, only one heater can be operated to avoid overheating of the substrate.

According to some embodiments, the first target temperature and the second target temperature are equal to a same value, said value being comprised between 230°C and 350°C, advantageously between 250°C and 300°C.

Thanks to these features, it is possible to avoid burning the substrate and consequently, emission of burnt and unpleasant elements for the user.

According to some embodiments, the controller is further configured to operate, after having carried out the second heating profile, according to at least one heating profile chosen in the group comprising at least:

- a third heating profile comprising activation of the heating element used in the second heating profile to achieve a third target temperature which is higher than the second target temperature;

- a fourth heating profile comprising deactivation of the heating element used in the second heating profile, and activation of the other heating element; and

- a fifth heating profile comprising activation of the two heating elements;

- a sixth heating profile comprising deactivation of each heating element. 4

Thanks to these features, it is possible to ensure an optimal operation of the device and optimal heat transfer, notably during the floating mode of operation of the device.

According to some embodiments, the heating chamber extends along the device axis and defines a rectangular cross-sectional shape having a first pair of walls facing each other and forming chamber lateral walls, and a second pair of walls facing each other and forming said heating walls.

Thanks to these features, it is possible to obtain a more homogeneous heat transfer inside the substrate.

According to some embodiments, each heating wall at least 3 times, advantageously 5 times and more advantageously 8 times, wider than each chamber lateral wall.

Thanks to these features, the non-heated lateral surfaces of the aerosol generating substrate can be neglected. Thus, the heat transfer inside the substrate can be more optimal.

According to some embodiments, each heating wall defines a contact surface designed to be in a tight contact with an external surface of the aerosol generating substrate when the aerosol generating substrate is inserted into the heating chamber.

Thanks to these features, heat transfer between the heating wall and the substrate can be further improved.

According to some embodiments, each heating element is attached to an outer surface of the corresponding heating wall, opposite to the contact surface of this heating wall.

Thanks to these features, the heating element may be arranged outside the heating chamber while ensuring an optimal heat transfer with the substrate.

According to some embodiments, each chamber lateral wall is designed to be spaced out from an external surface of the aerosol generating substrate when the aerosol generating substrate is inserted into the heating chamber. 5

Thanks to these features, an airflow channel can be formed between the lateral walls of the chamber and the substrate. This channel can be used to conduct fresh air from outside of the device until a flow inlet of the aerosol generating substrate. This makes it possible to provide the heating chamber only with one opening, i.e. the opening used for inserting the substrate. The opposite end of the heating chamber may be sealed. This can reduce heat loss from the chamber.

According to some embodiments, the heating chamber is configured to compress the heater part of the aerosol generating substrate when it is received in the heating chamber.

Thanks to these features, heat transfer inside the aerosol generating substrate can be further improved. Indeed, compressing the substrate leads to expulsion of air bubbles formed inside the chamber and acting thus as thermal insulators.

According to some embodiments, each heating element is attached to an outer surface of the heating chamber.

Thanks to these features, the heating element may be arranged outside the heating chamber while ensuring an optimal heat transfer with the substrate.

According to some embodiments, each heating element is a polyimide film heater.

Thanks to these features, the heating elements can be thin and can be used inside the aerosol generating device while keeping a compact shape of the device.

According to some embodiments, further comprising insulator arranged between an outer surface of the heating chamber and an inner surface of the device body.

Thanks to these features, the device body can be thermally isolated from the heating chamber. This reduces the risks of the device external surface overheating and consequently, of user’s injuring.

According to some embodiments, the heating chamber is made of a stainless steel. 6

Thanks to these features, the walls of the heating chamber can define good heat transfer properties.

The invention furthermore relates to an assembly comprising an aerosol generating device as described above and an aerosol generating substrate.

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:

- Figure 1 is a perspective view of an aerosol generating device according to a first embodiment of the invention;

- Figure 2 is a perspective view of an aerosol generating substrate usable with the aerosol generating device of Figure 1 ;

- Figure 3 is a perspective view of a mouthpiece of the aerosol generating device of Figure 1 ;

- Figure 4 is a perspective view of the mouthpiece of Figure 3 mounted on the housing of the aerosol generating device of Figure 1 ;

- Figure 5 is a perspective view of a heating chamber of the aerosol generating device of Figure 1 , the heating chamber receiving the aerosol generating substrate of Figure 2;

- Figure 6 is a view similar to the view of Figure 5 where the heating chamber and the aerosol generating substrate are shown without the housing;

- Figure 7 is a cross-sectional view of Figure 6 according to plane VII;

- Figure 8 is a perspective view of an aerosol generating device according to a second embodiment of the invention; 7

- Figure 9 is a perspective view of an aerosol generating device according to a third embodiment of the invention, and

- Figure 10 is a cross-sectional view similar to the view of Figure 7 showing a preferred example of a heater part of the aerosol generating substrate.

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 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 8 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 OF THE INVENTION

Figure 1 shows an aerosol generating device 10 according to the first embodiment of the invention. The aerosol generating device 10 is intended to operate with an aerosol generating substrate 12 shown in more detail on Figure 2.

In reference to Figure 2, the aerosol generating substrate 12 is for example a flat shaped cuboid extending along a substrate axis X and having external dimensions LxWxD. In a typical example, the length L of the substrate according to the substrate axis X equals substantially to 33 mm while its width W and depth D are substantially equal respectively to 12 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 substrate 12 is formed by a pair of parallel walls 13A, 13B, called hereinafter substrate lateral walls 13A, 13B, and the width W of the substrate is formed by a pair of parallel walls 14A, 14B, called hereinafter substrate contact walls 14A, 14B. According to other embodiments of the invention, the aerosol generating substrate 12 can have any other suitable shape and/or external dimensions. For example, the aerosol generating substrate 12 may form a circular tube shape.

The aerosol generating substrate 12 comprises a heater part 15 and a mouthpiece part 16 arranged along the substrate axis X. In some embodiments, the aerosol generating substrate 12 may comprise only the heater part 15. The heater part 15 may for example be slightly longer than the mouthpiece part 16. For example, the length L2 of the heater part 15 according to the substrate axis X may be substantially equal to 18 mm and the length L1 of the mouthpiece part 16 according to the substrate axis X may be substantially equal to 15 mm. The heater part 15 defines an abutting end 18 of the substrate 12 and the mouthpiece part 16 defines a mouth end 20 of the substrate 12. The heater part 15 and the 9 mouthpiece part 16 may be fixed one to the other by a unique wrapper extending around the substrate axis X. In other embodiments, the parts 15, 16 may be wrapped by different wrappers and fixed one to the other by any other suitable mean. The or each wrapper may, for example, comprise paper and/or non-woven fabric and/or aluminium. The or each wrapper may be porous or air impermeable. The or each wrapper forms a plurality of airflow channels extending inside the substrate 12 between the abutting end 18 and the mouth end 20.

The heater part 14 is intended to be heated by a heater (using a heating chamber in the present example) and comprises vaporizable material as defined above. According to the first and the second embodiments of the invention, the mouthpiece part 16 is intended to be received inside a mouthpiece as it will be explained in further detail below. According to other embodiments of the invention, the mouthpiece part 16 forms itself a mouthpiece intended to be in contact with the user’s mouth and/or lips. The mouthpiece part 16 comprises a core 17 acting for example like a filter. The core 17 may for example be a foam, or packed strands or fibres. The core 17 may be formed through an extrusion and/or rolling process into a stable shape. The substrate may be shaped to provide one or more airflow channels. In the particular example of Figure 2, the mouthpiece part 16 defines a plurality of venting holes 22 arranged for example according to the whole perimeter of the mouthpiece part 16 along two axis perpendicular to the substrate axis X. In other words, according to this example, the venting holes 22 are arranged on each wall of the substrate among the substrate lateral walls 13A, 13B and the substrate contact walls 14A, 14B. According to another example, the venting holes 22 are arranged only on the substrate contact walls 14A, 14B or preferably, only on one of the substrate contact walls 14A, 14B. In both examples, the venting holes 22 may be aligned perpendicularly to the substrate axis on the or each corresponding wall of the substrate 12, and can be spaced by a same distance. The venting holes 22 allow fresh air entering inside the substrate 12 to achieve particular vaping/tasting effects.

Referring again to Figure 1 , the aerosol generating device 10 comprises a device body 30 extending along a device axis Y and forming at least one side wall 40 of the device 10. The device body 30 comprises a mouthpiece 32 and a housing 34 arranged successively according to the device axis Y. According to the first embodiment of the invention, the mouthpiece 32 and the housing 34 form two different pieces. Particularly, according to this embodiment, the mouthpiece 32 is designed to be fixed on or be received in an insertion opening 36 formed at one of the ends of the housing 34. This opening 36 10 extends perpendicularly to the device axis Y as it is shown on Figure 5 where the mouthpiece 32 is removed from the housing 34.

In each cross section, the housing 34 may for example form a substantially rectangular shape with rounded edges. In this case, the housing 34 with the mouthpiece 32 form at least four side walls 40. According to other embodiments, the housing 34 can have a round cross-sectional shape. In this case, it can form with the mouthpiece 32 only one side wall 40. The housing 34 can be sealed at the end opposite to the insertion opening 36 receiving the mouthpiece 32. The housing 34 can be formed from a single piece or several assembled pieces made of any suitable material like aluminium or plastic. In some embodiments, the material of the housing 34 can be a thermally conductive material. In some other embodiments, it can be a thermally insulating material. In some embodiments, the housing 34 can form on the corresponding part of the device side wall 40 one or several openings suitable for arranging control and/or visual elements. For example, such element may comprise control buttons, touch panels, screens, LEDs, etc. Particularly, in the example of Figure 1 , the housing 34 forms a slot opening 42 receiving for example a LED indicating at least an ON state of the device 10. It can also indicate for example a battery law state, an error state, etc.

The housing 34 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 for powering the device 10, a controller 43 for controlling the operation of the device 10, a heating chamber 45 for heating the aerosol generating substrate 12 and at least two heating elements 47A, 47B for heating the heating chamber 45. In some embodiments, the housing 34 may further comprise at least one temperature sensor. This temperature sensor can for example generate temperature measurements relative to the temperature of the least one heating element 47A, 47B and/or of the aerosol generating substrate 12 and/or of the aerosol generated by the aerosol generating substrate.

Figure 3 shows in more detail the mouthpiece 32. In reference to this Figure 3, the mouthpiece 32 is delimited by an internal surface 56 intended to face the insertion opening 36 while assembling the mouthpiece 32 with the housing 34, and an external surface 57 intended to form with the housing 34 at least one side wall 40 of the device 10. An external border 59 of the internal surface 56 is designed to be in a tight contact with a part of an internal border of the insertion opening 36 to fix the mouthpiece 32 inside the insertion 11 opening 36. The external surface 57 has an appropriate shape to be in contact with the user’s mouth and/or lips. Each side of the external surface 57 can be formed as an extension of the corresponding side of the housing to form an almost continuous side wall 40 of the device 10. Particularly, in this case, a discontinuity can be formed in the transition zone between the mouthpiece 32 and the housing 34.

The mouthpiece 32 is crossed by a through-hole 60 extending along the device axis Y between a recess portion 62 and a flow outlet 64. Particularly, the through-hole 60 is designed to receive the mouthpiece part 16 of the aerosol generating substrate 12 so as the substrate axis X coincides with the device axis Y. Thus, the through-hole 60 has the same cross-sectional shape as the aerosol generating substrate 12 and defines internal dimensions slightly greater than the external dimensions of the mouthpiece part 16 of the aerosol generating substrate 12. Particularly, in the example of the figures, the through-hole 60 defines a rectangular cross-section to be able to receive the mouthpiece part 16 of the aerosol generating substrate 12 shown on Figure 2. In some embodiments, the through- hole 60 may have variable cross-sectional dimensions. For example, the through-hole 60 can have gradually decreasing cross-sectional dimensions (notably the width) from the recess portion 62 to the flow outlet 64. Additionally, the through-hole 60 and the mouthpiece part 16 of the aerosol generating substrate 12 can have the same length measured respectfully according to the device axis Y and the substrate axis X. According to another embodiment, the length of the mouthpiece part 16 of the aerosol generating substrate 12 can be less than the length of the through-hole 60 so as the mouth end 20 of the aerosol generating substrate 12 can be flushed at the flow outlet 64.

The recess portion 62 corresponds to a cavity formed in both internal and external surfaces 56, 57 of the mouthpiece 32. This cavity can be formed by a first opening extending on the internal surface 56 on one side of the through-hole 60 from the border 59 to this through-hole 60 and a second opening extending on the external surface 57 from the border following d% of the length of the mouthpiece 32 measured according to the device axis Y. The value d can be less than 25, advantageously less than 10 and more advantageously less than 5. Thus, when the mouthpiece 32 is inserted in the insertion opening 36, the recess portion 62 forms an opening 66 forming a flow inlet 66 as shown on Figure 4. In other words, the flow inlet 66 is formed on a side wall 40 of the device 10 in a transition zone between the mouthpiece 32 and the housing 34. 12

In the embodiment where the aerosol generating substrate 12 comprises the venting holes 22, at least some of these venting holes 22 are arranged to face the flow inlet 66.

According to another embodiment of the invention (not shown), a flow inlet is formed at any other wall of the device 10. It can for example be formed at the wall opposite to the mouthpiece 32.

In reference to Figures 5 to 7, the heating chamber 45 forms a cup-shaped heating chamber extending along the device axis Y between an open end 70 and a sealed end 71 . The heating chamber 45 is designed to receive the heater part 15 of the aerosol generating substrate 12. For this purpose, the heating chamber 45 defines substantially the same cross-sectional shape as the aerosol generating substrate 12. Particularly, in the example of the figures, the heating chamber 45 defines a rectangular cross-sectional shape with two parallel chamber lateral walls 73A, 73B and two parallel chamber contact walls 74A, 74B. Each chamber contact wall 74A, 74B is for example at least 3 times, advantageously 5 times and more advantageously 8 times, wider than each chamber lateral wall 73A, 73B.

Each heating wall 74A, 74B may be for example rigidly fixed to each chamber lateral wall 73A, 73B so as to define the rectangular cross-sectional shape, and in particular to form a cup shape of the heating chamber 45.

The heating walls 74A, 74B may be arranged opposite and in parallel one to another, in particular facing each other for example in the absence of the aerosol forming substrate 12.

According to embodiments, each heating element 47A, 47B may be parallel to a respective heating wall 74A, 74B of the heating chamber 45. For example, each heating element 47A, 47B may be arranged between the aerosol forming substrate 12 and the corresponding heating wall 74A, 74B or be integrate inside the corresponding heating wall 74A, 74B.

The heating chamber 45 also defines a distal wall 75 arranged perpendicularly to the device axis Y and sealing the sealed end 71. Particularly, the distal wall 75 is adjacent to each of the walls 73A, 73B, 74A, 74B so as to seal the chamber at the sealed end 71 and thus, form a cup shape of the chamber opening at the open end 70. Particularly, in this case, the only air permeable opening of the chamber 45 is formed at the open end 70. 13

According to another embodiment (not shown), the distal wall 75 defines an opening suitable for air entering inside the chamber 45 and notably inside the aerosol forming substrate 12. Each of the walls 73A, 73B, 74A, 74B, 75 can be made from a thermally conductive material like a metal, notably a stainless steel. Additionally, at least some of the walls 73A, 73B, 74A, 74B, 75 or all of these walls can form one single piece.

The internal dimensions of the heating chamber 45 are defined by the length L3 measured according the device axis Y, the width W3 measured as the distance between the chamber lateral walls 73A, 73B and the depth D3 measured as the distance between the chamber contact walls 74A, 74B. These internal dimensions L3, W3, D3 are chosen basing on the external dimensions L2, W, D of the heater part 15 of the aerosol generating substrate 12.

Particularly, the depth D3 of the heating chamber 45 is chosen slightly greater than the depth D of the aerosol generating substrate 12 or substantially equal to this depth D. In this case, the substrate contact walls 14A, 14B can be in contact with the chamber contact walls 74A, 74B and notably with contact surfaces of these walls 74A, 74B, when the heater part 15 of the of the aerosol generating substrate 12 is received inside the heating chamber 45. Advantageously, in this case, the chamber contact walls 74A, 74B and notably their contact surfaces, are in a tight contact with the substrate contact walls 14A, 14B. In some embodiments, the depth D3 of the heating chamber 45 can be even slightly less than the normal depth D of the aerosol generating substrate 12. In this case, the heating chamber 45 and/or the mouthpiece 32 is(are) configured to compress the heater part 15 of the aerosol generating substrate 12 by exerting force on the substrate contact walls 14A, 14B. This makes it possible to improve the tight contact between the corresponding contact walls of the heating chamber 45 and the substrate 12 and thus, to improve heat transfer between these walls.

For example, each substrate contact wall 14A, 14B consists of a first surface area of this wall of the heater part 15 and a second surface area of this wall of the mouthpiece part 16. According to some embodiments, each chamber contact wall 74A, 74B presents an area equal to or larger than the corresponding surface area of the heater part 15 of the aerosol generating substrate 12, e.g. the first surface area of the substrate contact wall 14A, 14B. This is for example visible in figure 6. In particular, each chamber contact wall 74A, 74B extends laterally, i.e. in a direction perpendicular to device axis Y, over edges of the surface area of the heater part 15. 14

The width W3 of the heating chamber 45 is chosen so as at least one pair of facing lateral walls 73A, 13A or 73B, 13B of the heating chamber 45 and the aerosol generating substrate 12 forms an airflow channel between them. Advantageously, the width W3 of the heating chamber 45 is chosen so as each pair of facing lateral walls 73A, 13A or 73B, 13B of the heating chamber 45 and the aerosol generating substrate 12 forms an airflow channel between them. In other words, the width W3 of the heating chamber 45 is chosen so as to form a distance d1 between each pair of facing lateral walls 73A, 13A or 73B, 13B as it is shown on Figure 7. Particularly, in the example of this Figure, W3=W+2d1 . The distance d1 may for example be chosen substantially equal to the depth D3 of the heating chamber 45. In this case, when the heater part 15 of the aerosol generating substrate 12 is inserted in the heating chamber 45, an airflow channel of substantially square cross-section is formed along the device axis Y on either lateral side of the aerosol generating substrate 12. Of course, the distance d1 may be chosen equal to any other value depending on the flow rate required inside the aerosol generating substrate 12 while its heating. Additionally, in this case, the distal wall 75 of the heating chamber 45 can form a rib or any other stopping mean preventing contact of the abutting end 18 of the aerosol generating substrate 12 with the distal wall 75 of the heating chamber 45. In other words, this stopping mean is configured to create an airflow channel connecting each of the airflow channels formed between the chamber lateral walls 73A, 73B and the aerosol generating substrate 12, with each airflow channel formed inside the aerosol generating substrate 12.

According to another embodiment of the invention (not-shown), no airflow channel between the pairs of facing lateral walls 73A, 13A or 73B, 13B of the heating chamber 45 and the aerosol generating substrate 12 is formed. In this case, these pairs of lateral walls 73A, 13A or 73B, 13B may be in contact, advantageously in tight contact between them. This embodiment is notably suitable when the distal wall 75 or any other wall of the heating chamber 45 forms an opening suitable for air entering.

As shown on Figures 6 and 7, each heating element 47A, 47B is arranged in contact with one of the chamber contact walls 74A, 74B outside of the heating chamber 45. Particularly, in the example of these Figures, the heating element 47A is arranged adjacent to an outer surface of the chamber contact wall 74A and the heating element 47B is arranged adjacent to an outer surface of the chamber contact wall 47A. Thus, the chamber contact walls 74A, 74B are also called heating walls 74A, 74B since they ensure heat 15 transfer from the heating elements 47A, 47B to the aerosol generating substrate 12. Each heating element 47A, 47B may comprise a polyimide film heater extending along substantially the total area of said outer surface of the corresponding heating wall 74A, 74B or only along a part of this surface. In this last case, said part may form a width substantially equal to the width W of the aerosol generating substrate 12. According to some embodiments, the aerosol generating device 10 further comprises an insulator arranged between each heating element 47A, 47B and an inner surface of the housing 34. The same insulator may also be arranged between an outer surface of each of the chamber lateral walls 73A, 73B and the inner surface of the housing 34.

The controller 43 is configured to control the operation of the aerosol generating device 10. For this purpose, the controller 43 may present at least one software and/or hardware component able to control the operation of the aerosol generating device 10 and notably, the operation of the heating elements 47A, 47B as it will be explained below in further detail. When the controller 43 presents at least one software component, this component can be carried out using an appropriate processor and memory comprised in the device 10. When the controller 43 presents at least one hardware component, such a component may present a programmable unit such for example Field Programmable Gate Arrays (known as “FPGA”).

Particularly, the controller 43 may be configured to operate separately the operation of each heating element 47A, 47B, according to a heating profile chosen among a predetermined group of heating profiles. The corresponding heating profile may be chosen according to a mode of operation of the device 10 and/or according to at least some external/internal parameters relative to the operation of the device 10.

The operation mode of the device can for example correspond to a pre-heating mode or a floating mode. During the pre-heating mode, the aerosol generating substrate 12 is heated from an ambient temperature to a temperature making it possible to generate aerosol. During the floating mode, the aerosol generating substrate 12 is heated to generate aerosol further to user puffs. Thus, the floating mode corresponds to a normal operation of the aerosol generating device 10 during a vaping session. The parameters relative to the operation of the device 10 may correspond to temperature measurements provided by a temperature sensor arranged for example inside the housing 34 as previously explained. As mentioned above, these temperature measurements may be relative to the temperature 16 of at least one or both heating elements 47A, 47B, to the temperature of the aerosol generating substrate 12 or to the temperature of the produced aerosol.

The controller 43 may for example be configured to choose a first heating profile during the pre-heating mode of operation of the device 10 and a second heating profile during at least at the beginning of the floating mode of operation of the device 10. For example, the first heating profile may comprise activation of both heating elements 47A, 47B until reaching a first target temperature and the second heating profile comprising activation of one of the heating elements (for example of the heating element 47A) until reaching a second target temperature. The second heating profile may further comprise activation/deactivation of the heating element 47A to maintain the second target temperature. In some embodiments, the first target temperature and the second target temperature may be equal to a same value, said value being comprised between 230°C and 350°C, advantageously between 250°C and 300°C. Advantageously, the value can correspond to the temperature of the aerosol generating substrate 12 making it possible to generate aerosol while user puffing, without burning the substrate.

In some embodiments, after having operated the heating elements 47A, 47B according to the second heating profile, the controller 43 is configured to operate these elements according to still another heating profile, chosen for example according to temperature measurements provided by the temperature sensor and/or according to predetermined time periods/frequencies. Such a heating profile may be chosen in the group comprising at least:

- a third heating profile comprising activation of the heating element used in the second heating profile (i.e. the heating element 47A according to the pre-cited example) to achieve a third target temperature which is higher than the second target temperature;

- a fourth heating profile comprising deactivation of the heating element used in the second heating profile (i.e. the heating element 47A according to the pre-cited example), and activation of the other heating element (i.e. the heating element 47B according to the pre-cited example); and

- a fifth heating profile comprising activation of the two heating elements 47A, 47B;

- a sixth heating profile comprising deactivation of each heating element 47A,47B.

Other heating profiles are also possible. Particularly, a heating profile may correspond to any combination of the pre-cited heating profiles. Moreover, in case of more than two heating elements, the heating profiles may be more complex and include activation of at 17 least a first group of heating elements and deactivation of at least a second group of heating elements, according to the mode of operation of the device and/or external/internal parameters such as temperature measurements. Additionally, it is clear that only certain (or only one) of the third to sixth heating profiles may be carried out during a vaping session, according to any suitable order.

The operation of the aerosol generating device 10 will now be described. Initially, it is considered that the aerosol generating substrate 12 is extracted from the device 10. In order to insert it, the user first takes off the mouthpiece 32 from the housing 34. Then, the user inserts the heater part 15 of the aerosol generating substrate 12 into the heating chamber 45 until the abutting end 18 of the substrate 12 abuts against the stopping mean of the distal wall 75. Then, the user fixes the mouthpiece 32 on the housing 34 by sliding the mouthpiece part 16 of the aerosol generating substrate 12 inside the through-hole 60 of the mouthpiece 32 and by inserting the mouthpiece 32 in the insertion opening 36 of the housing 34.

Then, the user can activate the operation of the aerosol generating device 10 by actuating for example an ON button or by performing a puff. This creates an airflow in an airflow path formed inside the device between the flow inlet 66 and the flow outlet 64 as it is shown on Figure 4.

Upon activation of the aerosol generating device 10, the controller 43 starts the pre heating mode of the operation and operates the heating elements 47A, 47B according to the first heating profile, as explained above. When the first target temperature is achieved, the controller 43 proceeds with the floating mode of operation of the device 10 and operates the heating elements 47A, 47B according to the second heating profile. After, the controller 43 may operate these heating elements according to at least another heating profile, as previously explained.

As visible in Figure 10, the heater part 15 of the aerosol generating substrate 12 may have for example a flat-plate shape with slotted grooves on both opposite surfaces.

SECOND EMBODIMENT OF INVENTION

Figure 8 shows an aerosol generating device 110 according to a second embodiment of the invention. This aerosol generating device 110 is similar to the aerosol generating 18 device 10 and notably, is configured to operate with the same aerosol generating substrate 12 shown on Figure 2.

The aerosol generating device 110 according to the second embodiment of the invention also comprises a device body 130 defining at least one side wall 140 of the device 110 and comprising a mouthpiece 132 and a housing 134 having similar external shapes as respectfully the mouthpiece 32 and the housing 34 explained before in relation with the first embodiment of the invention. However, according to the second embodiment of the invention, the mouthpiece 132 and the housing 134 form a single piece. In this case, the aerosol generating substrate can for example be loaded directly from an opening 164 of the mouthpiece 132. This opening 164 also forms a flow outlet 164 similar to the flow outlet 64 explained before. The aerosol generating substrate 12 can be extracted from the same opening 164 using for example an internal extracting mechanism which can be actuated by an actuator 142 arranged on the side wall 140.

The or each side wall 140 has for example a smooth external surface and defines a transition zone between the mouthpiece 132 and the housing 134. Furthermore, as in the previous case, the transition zone defines an opening 166 forming a flow inlet 166.

The interior part of the aerosol generating device 110 is similar to the interior part of the aerosol generating device 10 explained above. Particularly, the aerosol generating device 110 comprises the same heating chamber as the heating chamber 45 explained before and forming at least two heating walls. As in the previous case, a heating element is attached on the heating wall and can be controlled separately from each other heating element by a controller similar to the controller 43 explained above.

The operation of the aerosol generating device 110 is also similar to the operation of the aerosol generating device 10 explained above. The unique difference consists in the way of loading/extracting of the aerosol generating substrate 12.

THIRD EMBODIMENT OF INVENTION

Figure 9 shows an aerosol generating device 210 according to a third embodiment of the invention. This aerosol generating device 210 is similar to the aerosol generating device 110 according to the second embodiment of the invention and notably, is configured to operate with the same aerosol generating substrate 12 shown on Figure 2. 19

The aerosol generating device 210 according to the third embodiment of the invention also comprises a device body 230 defining at least one side wall 240 of the device 210. Contrary to the previous embodiments, the device body 230 according to the third embodiment of the invention does not define a mouthpiece. As it is shown on Figure 9, a mouthpiece is formed by at least a part of the mouthpiece part 16 of the aerosol generating substrate 12.

Particularly, according to this embodiment, the device body 230 forms an insertion opening 236 extending perpendicularly to the device axis Y at one of the ends of the device body 230. As in the second embodiment of the invention, the opening 236 is suitable to receive at least the heater part 15 of the aerosol generating substrate 12. Particularly, as in the previous cases, the opening 236 communicates with a heating chamber arranged inside the device body 230. This heating chamber is similar to the heating chamber explained above and notably, is adapted to receive the heater part 15 of the aerosol generating substrate 12. Additionally, as in the previous cases, at least two heating elements configured to be operated separately by a controller are provided.

Contrary to the previous cases, at least a part of the mouthpiece part 16 of the aerosol generating substrate 12 protrudes from the opening 236 forming thus a mouthpiece. In other words, this protruding part of the aerosol generating substrate 12 is designed to be in contact with the user’s lips and mouth while using the device 210 and forms a flow outlet 264.

As in the previous cases, a flow inlet 266 is formed on the side wall 240 of the device body 230. This flow inlet 266 is in a fluid communication with each of the airflow channels formed between the lateral walls of the heating chamber and the aerosol generating substrate 12. Additionally, as in the previous cases, the flow is forced inside the chamber to follow a “U” turn to flow inside the aerosol generating substrate 12 until the flow outlet

264.

When the aerosol generating substrate 12 comprises venting holes 22, these venting holes 22 may be arranged on the protruding part of the mouthpiece part 16 of the substrate 12 as it is shown on Figure 9. According to another example, the venting holes 22 are arranged on the part of the mouthpiece part 16 of the substrate 12 which is received inside 20 the device body 230, advantageously to face the flow inlet 266 as in the second embodiment of the invention.

As in the second embodiment of the invention, an actuator 242 may be arranged on the side wall 240 of the device 210 to facilitate the extraction of the aerosol generating substrate 12. According to another example, no actuator is provided on the side wall and the substrate 12 is extracted by pulling its protruding part.

FOURTH EMBODIMENT OF THE INVENTION

An aerosol generating device according to a fourth embodiment of the invention has the same structure as the aerosol generating device 110 according to the second embodiment of the invention, the only difference being in the nature of the substrate 12 that the aerosol generating device according to the fourth embodiment is able to receive. Particularly, it can be adapted to receive aerosol generating substrates of different lengths. For example, the aerosol generating device according to the fourth embodiment of the invention may be adapted to receive an aerosol generating substrate of a “normal” length, i.e. a substrate similar to the substrate of Figure 2. In this case, this aerosol generating device may operate like the aerosol generating device 110 according to the second embodiment of the invention, i.e. it may form a mouthpiece making a part of the device body. The aerosol generating device according to the fourth embodiment of the invention may also be adapted to receive an elongated aerosol generating substrate. In this case, the substrate can protrude from the device body and form a mouthpiece. In other words, in this case, the aerosol generating device according to the fourth embodiment of the invention may operate as the aerosol generating device 210 according to the third embodiment of the invention.