Aerosol generating device with leak prevention means and related aerosol generating assembly - Patents.com

Abstract

Aerosol generating device and associated aerosol generating assembly with leak prevention means. The present invention relates to an aerosol generating device configured to operate with a tobacco article having a substrate portion, the device comprising: a device body configured to receive the substrate portion and comprising a heating chamber defining an opening; and a mouthpiece secured to the device body and forming an interior volume between a fixed end and an inner surface of the mouthpiece, the mouthpiece configured to engage a mouthpiece portion of the tobacco article and defining at least one air flow inlet (65) on its inner surface in fluid communication with a closed end of the heating chamber, the aerosol generating device further comprising leak prevention means (180) for preventing leakage of flow from the interior volume (47) via the air flow inlet (65).

Description

[Technical field]

[0001] The present invention relates to an aerosol generating device equipped with a leak prevention means.

[0002] In particular, the aerosol generating device according to the invention is adapted to operate with tobacco articles, e.g., flat-shaped tobacco articles, that comprise, e.g., a solid substrate capable of forming an aerosol when heated. Thus, these types of aerosol generating devices, also known as heat-non-combustion devices, are adapted to generate an aerosol for inhalation by heating, rather than burning, the substrate, by conduction, convection, and / or radiation.

[0003] The present invention also relates to an aerosol generation assembly associated with such a device. [Background technology]

[0004] The popularity and use of risk reduction or risk modification devices (also known as vaporizers) has grown rapidly in recent years as an aid to assist habitual smokers wishing to quit smoking traditional tobacco products such as cigarettes, cigars, cigarillos and rolling tobacco. A variety of devices and systems are available that heat or warm a vaporizable substance, as opposed to burning tobacco in traditional tobacco products.

[0005] A commonly available risk reduction or risk modification device is the substrate heated aerosol generator or heat-not-burn device. This type of device generates an aerosol or vapor by heating an aerosol substrate, typically comprising moist tobacco or other suitable vaporizable material, to a temperature typically ranging from 150°C to 350°C. By heating, rather than burning or combusting, the aerosol substrate releases an aerosol that contains the ingredients desired by the user but does not contain the toxic and carcinogenic by-products of combustion and burning. Furthermore, the aerosol generated by heating tobacco or other vaporizable material typically does not contain the burnt or bitter taste resulting from combustion and burning that can be unpleasant to the user, and therefore the substrate does not require sugars and other additives that are typically added to such materials to make the smoke and / or vapor more palatable to the user.

[0006] Tobacco articles that can be used with such types of aerosol generating devices can take a variety of shapes. Some of them can be elongated sticks, or other suitable shapes, such as flattened shapes. However, the design of a tobacco article often involves a trade-off between its aesthetics and heating efficiency.

[0007] Some known aerosol generating devices that operate with solid tobacco substrates generate high levels of vapor at the substrate area, and in current designs, the vapor does not travel all the way through the designed path, including the mouthpiece area of ​​the article, and instead can travel back up and escape the device, reducing overall vapor efficiency. Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide an aerosol generating device with improved vapor efficiency. [Means for solving the problem]

[0009] To this end, the present invention relates to an aerosol generating device adapted to operate with a tobacco article comprising a substrate portion and a mouthpiece portion arranged successively along an article axis, the aerosol generating device comprising: - a device body along the device axis from the fixed end, the device body being configured to receive a substrate portion of a tobacco article and comprising a heating chamber defining an opening adjacent the fixed end of the device body and a closed end opposite the opening along the device axis; - a mouthpiece secured to a fixed end of the device body and defining an interior volume between the fixed end and an inner surface of the mouthpiece, the mouthpiece configured to engage a mouthpiece portion of the tobacco article and defining at least one air flow inlet on its inner surface in fluid communication with the closed end of the heating chamber; Equipped with.

[0010] The aerosol generating device further comprises a leak prevention means for preventing leakage of flow from the interior volume through the air inlet.

[0011] Thanks to these features, it is possible to avoid leakage of flow from the internal volume of the mouthpiece and thus improve the overall vapor efficiency of the device. In particular, it has been observed that in devices that define an internal volume below the mouthpiece, backflow may occur while the user is puffing, which flow may exit the device through the air inlet. The leakage prevention means according to the invention prevents such a situation and thus improves the overall vapor efficiency of the device.

[0012] According to some embodiments, the leak prevention means comprises a valve disposed in the air inlet.

[0013] According to some embodiments, the valve is configured to open while the user is puffing and close when the user is not puffing.

[0014] These features allow for a simple and inexpensive way to prevent leakage of flow from the air inlet, so the valve forms a one-way fluid valve that allows air to enter the device when the user puffs, but prevents vapour from escaping back out.

[0015] According to some embodiments, the valve opens directly into the interior volume.

[0016] These features allow the airflow to be easily guided to the heating chamber. Additionally, in some cases, the incoming airflow can contact the tobacco article, such as the mouthpiece portion of the tobacco article, which can cool the mouthpiece portion and improve the user's perception of the inhaled flow.

[0017] According to some embodiments, the valve is a duckbill valve.

[0018] Duckbill valves are the preferred valve of choice because they can be made in small sizes and are easy to implement, although other types such as conventional spring-assisted check valves can also be used.

[0019] According to some embodiments, an air flow path is formed between the air inlet and the closed end of the heating chamber, the air flow path being formed by an upstream portion extending from the air inlet through the interior volume and a downstream portion extending from the upstream portion to the closed end of the heating chamber.

[0020] These features allow air from the exterior of the device to be directed to the closed end of the heating chamber. The air then passes through the interior of the tobacco article, first through the substrate portion and then through the mouthpiece portion. After the mouthpiece portion, the flow is directly inhaled by the user.

[0021] According to some embodiments, the downstream portion of the air flow path extends outside or inside the heating chamber.

[0022] According to some embodiments, the downstream portion of the air flow passage extends along a sidewall of the heating chamber.

[0023] When the downstream portion extends into the interior of the heating chamber, it can extend from the opening to a closed end of the heating chamber. The downstream portion can extend, for example, between a wall of the heating chamber and a wall of the tobacco article. To this end, the cross-section of the heating chamber can have at least one dimension that is larger than a corresponding dimension of the cross-section of the tobacco article.

[0024] When the downstream portion extends outside the heating chamber, the downstream portion can extend along at least one wall of the heating chamber, such as a side wall (also referred to herein as a narrow wall), and open at a closed end of the heating chamber. This improves the amount of air drawn through the substrate portion and reduces the importance of consumable fit within the heating chamber. This also provides a more consistent pressure drop from one tobacco article to another.

[0025] According to some embodiments, the leak prevention means comprises a bypass flow path forming an upstream portion of the air flow path, the bypass flow path being fluidly isolated from the interior volume.

[0026] Thanks to these features, it is possible to isolate the internal volume of the mouthpiece from the air inlet. Therefore, it is possible to avoid backflow near the air inlet. According to this embodiment, the air inlet may or may not be provided with a valve as described above. Specifically, when no valve is provided, backflow is avoided only by the bypass flow path. When a valve is provided, backflow is avoided using both the valve and the bypass flow path elements.

[0027] According to some embodiments, at least a portion of the bypass flow path is bounded by a tube extending through the interior volume.

[0028] Thanks to these features, a bypass flow path can be easily implemented to isolate the internal volume.

[0029] According to some embodiments, the mouthpiece defines at least two air inlets on an interior surface thereof in fluid communication with the closed end of the heating chamber, and the aerosol generating device includes a leak prevention means for each air inlet.

[0030] These features allow a greater amount of airflow through the tobacco article. The air inlets can be provided with the same or different leak prevention means. For example, at least one air inlet can be provided with a valve as described above and at least one air inlet can be provided with a bypass flow path as described above. According to another embodiment, each air inlet is provided with a valve as described above or a bypass flow path as described above.

[0031] According to some embodiments, the mouthpiece defines a through hole configured to engage with a mouthpiece portion of a tobacco article.

[0032] Thanks to these features, the through-hole can be adapted to fit tightly with the tobacco article and thus avoid or minimize flow leakage between the mouthpiece and the tobacco article. In addition, the through-hole can be adapted to maintain the tobacco article, for example, during removal of the tobacco article from the device and / or insertion into the device. In addition, in some cases, the mouthpiece can also be adapted to maintain the tobacco article in the heating chamber at a distance from the heating wall. Thus, it is possible to ensure heating of the tobacco article by convection instead of conduction, for example.

[0033] According to some embodiments, the air inlets are located on different sides of the through hole.

[0034] The air inlets can, for example, be arranged symmetrically with respect to the through-hole. In addition, the leakage prevention means can also be arranged symmetrically with respect to the through-hole.

[0035] According to some embodiments, it is configured to operate with flat shaped tobacco articles.

[0036] These features allow the tobacco article to be easily heated while still being compact and easy for the user to handle.

[0037] The present invention also relates to an aerosol generation assembly comprising a tobacco article and an aerosol generation device as defined above configured to operate with the tobacco article.

[0038] The invention and its advantages will be better understood on reading the following description, given by way of non-limiting example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0039] [Figure 1] FIG. 1 is a perspective view of an aerosol generation assembly according to the present invention, the aerosol generation assembly comprising an aerosol generation device according to the present invention and a tobacco article usable with the aerosol generation device. [Diagram 2] FIG. 2 is a perspective view of the tobacco article of FIG. 1. [Diagram 3] 2 is a partial cross-sectional view of the aerosol generation assembly of FIG. 1 taken along a longitudinal vertical plane of FIG. 1. [Figure 4] 2 is a partial cross-sectional view of the aerosol generation assembly of FIG. 1 along a longitudinal horizontal plane of FIG. 1, the aerosol generation device being provided with a leak prevention means according to a first embodiment of the present invention; [Diagram 5] 5 is a detailed view illustrating the operation of the leak prevention means of FIG. 4. [Figure 6] FIG. 5 is a partial cross-sectional view similar to that of FIG. 4, showing an aerosol generating device equipped with a leak prevention means according to a second embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Before the present invention is described, it is to be understood that the invention is not limited to the details of construction set forth in the following description, as it will be apparent to one skilled in the art having the benefit of this disclosure that the invention is capable of other embodiments and of being practiced or carried out in various ways.

[0041] As used herein, the term "aerosol generating device" or "device" may include a vaping device for delivering aerosol to a user, including aerosol for vaping, using a heater element, as described in more detail below. The device may be portable. "Portable" may refer to a device for use while held by a user. The device may be adapted to generate a variable amount of aerosol (as opposed to a metered spray of aerosol), for example by activating the heater element for a variable amount of time, which may be controlled by a trigger. The trigger may be user-activated, such as a vaping button and / or an inhalation sensor. The inhalation sensor may be sensitive to inhalation intensity and duration to allow for providing a variable amount of vapor (to mimic the smoking effect of a conventional combustion smoking article, such as a cigarette, cigar, or pipe). The device may include a temperature regulation control for driving the temperature of the heater and / or heated aerosol-generating material (aerosol precursor) to a specified target temperature and then maintaining the temperature at a target temperature that allows for efficient generation of aerosol.

[0042] As used herein, the term "aerosol" may include a suspension of vaporizable material as one or more of solid particles, liquid droplets, or gas. The suspension may be in a gas, including air. Aerosol herein may generally refer to / include a vapor. Aerosol may include one or more components of vaporizable material.

[0043] As used herein, the term "vaporizable material" or "precursor" may refer to a smokable material that may include, for example, nicotine or tobacco and an aerosol-forming agent. Tobacco may take the form of various materials, such as cut tobacco, granulated tobacco, tobacco leaf, and / or reconstituted tobacco. Suitable aerosol-forming agents include polyols (e.g., sorbitol, glycerol, and glycols, such as propylene glycol or triethylene glycol), non-polyols (e.g., 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 include at least one of a gelling agent, a binder, a stabilizer, and a humectant.

[0044] Figure 1 shows an aerosol generating assembly 10 comprising an aerosol generating device 11 and a tobacco article 12. The aerosol generating device 11 is intended to operate with a tobacco article 12, which is shown in more detail in Figure 2.

[0045] In this example of FIG. 2, the tobacco article 12 is a flat-shaped tobacco article, e.g., a flat rectangular parallelepiped extending along the article axis X and having external dimensions L×W×D. In a typical example, the length L of the article 12 along the article axis X is approximately equal to 33 mm, while its width W and depth D are approximately equal to 12 mm and 1.2 mm, respectively. According to different examples, the values ​​L, W and D can be selected, for example, within a range of ±40%. The depth D of the tobacco article 12 is formed by a pair of parallel walls 13A, 13B, hereinafter referred to as narrow walls 13A, 13B, and the width W of the substrate is formed by a pair of parallel walls 14A, 14B, hereinafter referred to as wide walls 14A, 14B. In some embodiments, the edges between the wide and narrow walls 13A, 13B, 14A, 14B may be rounded. According to other embodiments of the present invention, the tobacco article 12 can have other suitable flat shapes and / or external dimensions. According to yet other embodiments, the tobacco article 12 may take on other suitable shapes, such as, for example, a stick shape.

[0046] The tobacco article 12 comprises a substrate portion 15 and a mouthpiece portion 16 arranged along the article axis X. The substrate portion 15 may, for example, be slightly longer than the mouthpiece portion 16. For example, the length L2 of the substrate portion 15 along the article axis X may be substantially equal to 18 mm, and the length L1 of the mouthpiece portion 16 along the article axis X may be substantially equal to 15 mm. The substrate 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 substrate portion 15 and the mouthpiece portion 16 may be secured to each other by a wrapper 21 extending around the substrate axis X. 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 the same wrapping sheet. In other embodiments, the wrapper 21 is formed from separate wrapping sheets that separately wrap the portions 15, 16 and are secured one to the other by other suitable means. The wrapper 21 may comprise, for example, paper, and / or a nonwoven fabric, and / or aluminum foil. The wrapper 21 may be porous or air impermeable and defines a plurality of air passages extending into the interior of the article 12 between the abutting end 18 and the mouth end 20.

[0047] The mouthpiece portion 16 comprises a core 27 intended to act as a cooler, for example to slightly cool the vapour before the user inhales. The core 27 may for example comprise cardboard for this purpose. The core 27 may be formed into a stable shape through an extrusion and / or rolling process. Advantageously, the core 27 is arranged inside the mouthpiece portion 16 so as to be in full contact with the inner surface of the wrapper 21 and to delimit this mouthpiece portion 16.

[0048] As will be discussed in more detail below, substrate portion 15 includes a vaporizable material and is intended to be heated by a heating chamber.

[0049] 1, the aerosol generating device 11 comprises a device body 40 extending along a device axis Y, and a mouthpiece 42. According to the example described below, the mouthpiece 42 and the device body 40 form two different parts. In particular, according to this example, the mouthpiece 42 is designed to be fixed to a fixed end of the device body 40.

[0050] As shown in FIG. 3, the mouthpiece 42 comprises a central portion 43 and a peripheral portion 44 extending around the central portion 43. The peripheral portion 44 defines, for example, a collar that partially covers the outer surface of the device body 40 when the mouthpiece 42 is fixed to the fixed end of the device body 40. For example, the peripheral portion 44 can be designed to cooperate with a gasket 45 disposed at the fixed end of the device body 40 to seal a space formed between the peripheral portion 44 and the outer surface of the device body 40. The peripheral portion 44 also defines an intermediate portion that extends, for example, transversely to the device axis Y and forms a transition between the central portion 43 of the mouthpiece 42 and the collar defined by the peripheral portion 44. The central portion 43 of the mouthpiece 42 defines a through hole 46 adapted to at least partially receive the tobacco article 12. Specifically, the through hole 46 can be adapted to receive at least a portion of the mouthpiece portion 16 of the tobacco article 12, as shown in FIG. 3. Advantageously, the through hole 46 may be adapted to fit tightly with the mouthpiece portion 16 of the tobacco article 12 so as to avoid or minimize flow leakage between the walls bounding the through hole 46 and the exterior surface of the tobacco article 12. In some embodiments, the tobacco article 12 may be held within the through hole 46, for example, by friction. In this case, for example, it is possible to first insert the mouthpiece portion 16 of the tobacco article 12 inside the through hole 46 and then secure both elements to the fixed end of the device body 40.

[0051] 3, an interior volume 47 is defined between an inner surface 48 of the mouthpiece 42 and the fixed end of the device body 40. This interior volume 47 is traversed by the tobacco article 12 when the tobacco article 12 is inserted within the device body 40. For example, the tobacco article 12 may divide the interior volume 47 into two symmetrical portions.

[0052] The device body 40 defines an interior space of the device 11 that houses various elements designed to perform different functions of the device 11. This interior space may house, for example, a battery for powering the device 11, a control module for controlling the operation of the device 11, a heating chamber 50 for heating the substrate portion 15 of the tobacco article 12, etc. Of these elements, only the heating chamber 50 will be described in further detail with reference to FIG.

[0053] Specifically, as shown in this Figure 3, the heating chamber 50 may form a cup shape adapted to receive at least the substrate portion 15 of the tobacco article 12, and in some cases at least a portion of the mouthpiece portion 16. Similar to the tobacco article 12, the heating chamber 50 may also form a rectangular parallelepiped shape extending along the device axis Y, with a pair of parallel narrow walls 53A, 53B (shown in Figures 4 and 6) extending along the device axis Y, a pair of parallel wide walls 54A, 54B also extending along the device axis Y, and a bottom wall 58 adjacent said walls and extending perpendicular to the device axis Y. The bottom wall 58 thus forms a closed end of the chamber 50. The heating chamber 50 defines an opening 60 opposite the bottom wall 58 that is configured to receive the tobacco article 12 such that the corresponding broad walls 14A, 14B of the tobacco article 12 face the corresponding broad walls 54A, 54B of the heating chamber 50, the corresponding narrow walls 13A, 13B of the tobacco article 12 face the corresponding narrow walls 53A, 53B of the heating chamber 50, and the abutment end 18 of the tobacco article 12 abuts the bottom wall 58 or at least a rib extending from the bottom wall 58. Alternatively, the abutment end 18 faces the bottom wall 58 without contacting the bottom wall 58. Thus, the heating chamber 50 is configured to receive the tobacco article 12 such that the narrow wall 13A (or 13B) of the tobacco article 12 faces the narrow wall 53B (or 53A) of the heating chamber 50, and the wide wall 14A (or 14B) of the tobacco article 12 faces the wide wall 54B (or 54A) of the heating chamber 50. The opposing wide walls 14A, 14B, 54A, 54B and the opposing narrow walls 13A, 13B, 53A, 53B can be in contact with each other or can be spaced apart from each other.

[0054] The heating chamber 50 further comprises one or more heating elements (not shown) arranged to heat the substrate portion 15 of the tobacco article 12. According to different embodiments of the invention, the or each heating element may represent, for example, a resistive element arranged adjacent to at least one of the walls 53A, 53B, 54A, 54B of the heating chamber 50. Advantageously, a resistive heating element, for example a heating track or a polyimide film heater, is arranged adjacent to each wide wall 54A, 54B of the heating chamber 50, for example on the outer surface of such wall. According to other embodiments of the invention, the or each heating element represents other suitable means, for example a heating blade penetrating the substrate portion 15 of the tobacco article 12. According to yet another embodiment, the or each heating element represents a magnetic element capable of causing heating of a plurality of susceptors included in the substrate portion 15 by magnetic induction.

[0055] To ensure a user's puff, an air flow passage is formed inside the aerosol generating device 11, extending from an air inlet 65 (shown in Figures 4 and 6) to the closed end of the heating chamber 50. Thus, air enters the heating chamber 50 through the air flow passage, passes first through the substrate portion 15, then through the mouthpiece portion 16 of the tobacco article 12, and is then delivered to the user. According to the present invention, the air inlet 65 is disposed in the mouthpiece 42, advantageously in the middle portion of the periphery 44 of the mouthpiece 42. The air inlet 65 may be formed by a through hole.

[0056] The air flow path is formed by an upstream portion extending from the air inlet 65 and a downstream portion extending from the upstream portion to the closed end of the heating chamber 50. According to different embodiments of the invention, the downstream portion can extend inside or outside the heating chamber 50. For example, according to one embodiment, the downstream portion extends inside the heating chamber 50 from the opening 60 to the closed end of the heating chamber 50. In this case, the downstream portion can be formed between the narrow walls 13A, 13B of the tobacco article 12 and the corresponding narrow walls 53A, 53B of the heating chamber 50. According to another embodiment, the downstream portion extends outside the heating chamber through a dedicated flow path, for example extending along the narrow walls 53A, 53B of the heating chamber 50. In this case, the downstream portion opens into the closed end of the heating chamber 50. The location of the upstream portion depends on the different embodiments of the invention, which are explained in more detail below.

[0057] In some embodiments, multiple air flow paths can be formed inside the aerosol generating device 11, each of which is similar to the flow paths described above. For example, the air flow paths can be arranged symmetrically with respect to the through hole 46 of the mouthpiece 42. In the illustrated example, two air flow paths are arranged symmetrically with respect to the through hole 46.

[0058] According to the invention, the aerosol generating device 11 further comprises leak prevention means 180, 280 for preventing leakage of the flow from the internal volume 47. The implementation of these leak prevention means 180, 280 depends on the different embodiments of the invention, which are explained in more detail below.

[0059] [First embodiment] A leak prevention means 180 according to a first embodiment of the present invention will now be described with reference to FIG.

[0060] According to this embodiment, the leakage prevention means 180 comprise a valve arranged at the or each air inlet 65. In addition, according to this embodiment, the or each air inlet 65 opens directly into the internal volume 47. Thus, in this case, an upstream part of the corresponding air flow path extends through this internal volume 47, for example without being bounded inside this volume.

[0061] An example of a valve forming the leak prevention means 180 is shown in Figure 5. According to this example, the valve is a duckbill valve configured to be open while the user is puffing (configuration shown in the upper part of the figure) and to be closed when the user is not puffing (configuration shown in the lower part of the figure). In other words, the valve is configured to be open when there is air flow from the outside to the inside of the device 11 and to be closed otherwise.

[0062] [Second embodiment] A leakage prevention means 280 according to a second embodiment of the present invention will now be described with reference to FIG.

[0063] According to this embodiment, the leak prevention means 280 comprises a bypass flow path extending from the air inlet 60 through the internal volume 47 while being fluidly isolated from the internal volume 47. The bypass flow path thus forms an upstream portion of a corresponding air flow path. In a preferred embodiment, in this case, a downstream portion of the corresponding air flow path extends outside the heating chamber 50.

[0064] According to some examples of the second embodiment, the bypass flow path 280 is bounded by a tube extending through the interior volume 47. According to other examples, the bypass flow path 280 is at least partially defined by one or more surfaces bounding the interior volume 47.

[0065] The second embodiment can be combined with the first embodiment, in which at least one air flow path can be associated simultaneously with a valve and a bypass flow path. According to another example, at least one air flow path can be associated with a valve and at least one other air flow path can be associated with a bypass flow path.

Claims

1. 1. An aerosol generating device (11) configured to operate with a tobacco article (12) comprising a substrate portion (15) and a mouthpiece portion (16) arranged successively along an article axis (X), said aerosol generating device (11) comprising: a device body (40) extending from a fixed end along a device axis (Y), the device body (40) being configured to receive the substrate portion (15) of the tobacco article (12), the device body (40) comprising a heating chamber (50) defining an opening (60) adjacent the fixed end of the device body (40) and a closed end opposite the opening (60) according to the device axis (Y); a mouthpiece (42) secured to the fixed end of the device body (40) and defining an interior volume (47) between the fixed end and an inner surface (48) of the mouthpiece (42), the mouthpiece (42) being configured to engage the mouthpiece portion (16) of the tobacco article (12) and defining at least one air inlet (65) on the inner surface (48) in fluid communication with the closed end of the heating chamber (50); Equipped with the aerosol generating device (11) further comprises a leakage prevention means (180, 280) for preventing leakage of air from the internal volume (47) through the air inlet (65); Aerosol generator (11).

2. 2. The aerosol generating device (11) according to claim 1, wherein the leak prevention means (180) comprises a valve arranged in the air inlet (65).

3. 3. The aerosol generating device (11) of claim 2, wherein the valve (180) is configured to open while a user is puffing and to close when the user is not puffing.

4. 3. The aerosol generating device (11) of claim 2, wherein the valve (180) opens directly into the internal volume (47).

5. 3. The aerosol generating device (11) of claim 2, wherein the valve (180) is a duckbill valve.

6. 2. The aerosol generating device (11) of claim 1, wherein an air flow path is formed between the air inlet (65) and the closed end of the heating chamber (50), the air flow path being formed by an upstream portion extending from the air inlet (65) through the internal volume (47) and a downstream portion extending from the upstream portion to the closed end of the heating chamber (50).

7. 7. The aerosol generating device (11) according to claim 6, wherein the downstream portion of the air flow path extends outside or inside the heating chamber (50).

8. 7. The aerosol generating device (11) according to claim 6, wherein the downstream portion of the air flow path extends along a side wall of the heating chamber (50).

9. 7. The aerosol generating device (11) of claim 6, wherein the leak prevention means (280) comprises a bypass flow path forming the upstream portion of the air flow path, the bypass flow path being fluidically isolated from the internal volume (47).

10. 10. The aerosol generating device (11) of claim 9, wherein at least a portion of the bypass flow path (280) is bounded by a tube extending through the interior volume (47).

11. the mouthpiece (42) defines at least two air inlets (65) on the interior surface (48) that are in fluid communication with the closed end of the heating chamber (50); The aerosol generating device (11) is provided with a leak prevention means (180, 280) for each air inlet.

2. An aerosol generating device (11) according to claim 1.

12. 2. The aerosol generating device (11) of claim 1, wherein the mouthpiece (42) defines a through-hole (46) configured to engage the mouthpiece portion (16) of the tobacco article (12).

13. 13. The aerosol generating device (11) according to claim 12, wherein the air inlets (65) are arranged on different sides of the through-hole (46).

14. 10. The aerosol generating device (11) of claim 1, configured to operate with a flat-shaped tobacco article (12).

15. An aerosol-generating assembly (10) comprising a tobacco article (12) and an aerosol-generating device (11) according to any one of claims 1 to 14 configured to operate with the tobacco article (12).

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