WO2022243277A1 - Aerosol generation device with smoothed out pressure drop - Google Patents

Abstract

An aerosol generation device (1) comprises: - an aerosol generation unit (2) arranged for transforming an aerosol- forming substance (4) mixed with air into an aerosol that may be inhaled by a user through successive draws, and - an air flow channel (3) having an inner surface (17), at least one inlet (10) and an outlet (11), allowing air, sucked by the user, to pass through and to be mixed with the aerosol-forming substance (4), and comprising at least one area having an inner section and comprising at least one flexible baffle (18) extending from the inner surface (17) on a part of the inner section and configured during a draw for deflecting when the draw pressure in this area exceeds a predetermined threshold to reduce a pressure drop between sub-areas located upstream and downstream of this area.

Description

AEROSOL GENERATION DEVICE WITH SMOOTHED OUT PRESSURE

DROP

Field of the invention [01] The present invention relates to an aerosol generation device, and more precisely to the variations of the pressure drop experienced by the user of such a device during a vaping session.

Background [02] Some aerosol generation devices comprise an aerosol generation unit arranged for transforming an aerosol-forming substance mixed with air into an aerosol that may be inhaled by a user through successive draws (or puffs or else inhalation phases), and an air flow channel allowing air, sucked by this user, to pass through and to be mixed with this aerosol- forming substance.

[03] When this type of aerosol generation device is portable, i.e. usable when held by a user, it further comprises a battery (or power source) possibly rechargeable and storing electrical energy that is used by the aerosol generation unit for generating the aerosol. In this case the aerosol generation device may be a vaporizer or an electronic cigarette.

[04] In the following description the term “aerosol-forming substance” is used to designate any substance that is aerosolizable in air to form an aerosol. It may, for instance, be in liquid form, in solid form, or in a semi liquid form. So, it may be a liquid, gel, paste or wax or the like, or any combination of these.

[05] The aerosol-forming substance may comprise one or more of nicotine, polyol, caffeine or other active components. An active component may be carried by a carrier which may include propylene glycol or glycerin, for instance. A flavoring may also be present in the aerosol-forming substance. This flavoring may include Ethylvanillin (vanilla), menthol,

Isoamyl acetate (banana oil) or similar, for instance. [06] Moreover, in the following description the term “aerosol” may include a suspension of substance as one or more of solid particles, liquid droplets and gas. Such a suspension may be in a gas including air. Aerosol herein may generally refer to, or include, a vapor, and may include one or more components of the aerosol-forming substance.

[07] During a vaping session the strength of the user suction may vary between draws (or puffs) or even during the same draw (or puff). This induces variations of the pressure drop that are experienced by the user and may affect his inhalation pleasure.

[08] Therefore, an object of this invention is to improve the situation, and notably to allow smoothing out the pressure drop experienced by the user for different suction strengths.

Summary of the invention

[09] The proposed invention provides notably an embodiment of an aerosol generation device comprising:

- an aerosol generation unit arranged for transforming an aerosol-forming substance mixed with air into an aerosol that may be inhaled by a user through successive draws, and

- an air flow channel having an inner surface, at least one inlet and an outlet, and allowing air, sucked by the user, to pass through a vaporization area and to be mixed with the aerosol-forming substance.

[10] This aerosol generation device is characterized in that its air flow channel comprises at least one area having an inner section and comprising at least one flexible baffle extending from its inner surface on a part of the inner section and configured during a draw for deflecting when the draw pressure in this area exceeds a predetermined threshold to reduce a pressure drop between sub-areas located upstream and downstream of this area, wherein deflection of said at least one flexible baffle is operable to increase a mean free airflow path between the at least one inlet and the outlet. [11] Because this deformation increases the mean free air flow path (or passage) in the air flow channel area, this allows an increased air flow rate through the air flow channel, which allows to smooth out the pressure drop experienced by the user for various different suction strengths.

[12] The embodiment of aerosol generation device may comprise other aspects or features, considered separately or combined, as defined hereafter:

• each flexible baffle may be configured for having a deflection that varies with a difference between the draw pressure in its area and the predetermined threshold;

• each flexible baffle may extend in a direction perpendicular to an extension axis of its airflow channel area;

• each flexible baffle may be configured for deflecting in a direction of an extension axis of its airflow channel area;

• its air flow channel may comprise at least two first sub-parts each comprising an inlet and a second sub-part communicating with these first sub-parts and comprising the outlet;

• its air flow channel may comprise at least two areas each comprising at least one flexible baffle. For instance, each air flow channel area may belong to one of the first sub-parts, or each air flow channel area may belong to the second sub-part, or else each of the first and second sub parts may comprise at least one airflow channel area;

• at least two successive flexible baffles may extend from opposite parts of the inner surface and may belong to successive air flow channel areas separated therebetween by a chosen distance;

• at least one air flow channel area may comprise two flexible baffles arranged opposite to each other with a passage therebetween to allow air to pass through;

• at least one air flow channel area may comprise a plurality of flexible baffles together defining a minimum cross-sectional area when undeflected and operable to deflect to together define an increased cross-sectional area;

• the or each flexible baffle may comprise a curved surface having a convex side presented towards said inlet;

• the at least one flexible baffle may define a spiral surface;

• the aerosol-forming substance may comprise a tobacco material or at least one polyol;

• the aerosol generation device may comprise a rechargeable power source storing electrical energy;

• the aerosol generation device may constitute an electronic cigarette.

Brief description of the figures

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

- the figure 1 (FIG.1 ) schematically and functionally illustrates a first example of embodiment of an aerosol generation device according to the invention,

- the figure 2 (FIG.2) schematically and functionally illustrates an air flow channel area of the aerosol generation device of figure 1, comprising a flexible baffle without deflection,

- the figure 3 (FIG.3) schematically and functionally illustrates the air flow channel area of figure 2 with its flexible baffle deflected,

- the figure 4 (FIG.4) schematically and functionally illustrates a second example of embodiment of an aerosol generation device according to the invention,

- the figure 5 (FIG.5) schematically and functionally illustrates an air flow channel area of the aerosol generation device of figure 4, comprising a flexible baffle without deflection, - the figure 6 (FIG.6) schematically and functionally illustrates the air flow channel area of figure 5 with its flexible baffle deflected,

- the figure 7 (FIG.7) schematically and functionally illustrates a third example of embodiment of an aerosol generation device according to the invention,

- the figure 8 (FIG.8) schematically and functionally illustrates a fourth example of embodiment of an aerosol generation device according to the invention,

- the figure 9 (FIG.9) schematically and functionally illustrates a fifth example of embodiment of an aerosol generation device according to the invention,

- the figure 10 (FIG.10) schematically and functionally illustrates a sixth example of embodiment of an aerosol generation device according to the invention, - the figure 11 (FIG.11) schematically and functionally illustrates a seventh example of embodiment of an aerosol generation device according to the invention,

- the figure 12 schematically illustrates an air flow channel area comprising a plurality of flexible baffles in an undeflected state (FIG. 12A) and in a deflected state (FIG. 12B),

- the figure 13 schematically illustrates an air flow channel area comprising a helical flexible baffle in an undeflected state (FIG. 13A) and in a deflected state (FIG. 13B),

- the figure 14 (FIG. 14) schematically illustrates an air flow channel area comprising an alternative helical flexible baffle in an undeflected state, and

- the figure 15 (FIG. 15) schematically illustrates an air flow channel area comprising a further alternative helical flexible baffle in an undeflected state. Detailed description of embodiments

[14] The invention aims, notably, at offering an aerosol generation device 1 that allows smoothing out the pressure drop experienced by the user for different suction strengths. [15] In the following description it will be considered that the aerosol generation device 1 is (or constitutes) an electronic cigarette (or e-cigarette or else personal vaporizer). But an aerosol generation device 1 according to the invention could be of another type, as soon as it is arranged for transforming an aerosol-forming substance mixed with air into an aerosol (possibly close to room temperature) that may be inhaled by a user through successive puffs (or draws or inhalation phases) during a vaping session. More generally, the invention concerns any type of aerosol generation device, and notably the so-called Έ-vapor devices” comprising a resistive or inductive heater for heating a liquid and “T-vapor (or heat-not-burn (or “HnB”)) devices” comprising a heater for heating a “solid” substance (for instance a tobacco stick) and similar to a traditional cigarette.

[16] It is recalled that an “aerosol-forming substance” is used to designate any material that is aerosolizable in air to form an aerosol. It may, for instance, be in liquid form, in solid form, or in a semi liquid form. So, it may be a liquid, gel, paste or wax or the like, or any combination of these, and may comprise one or more of nicotine, polyol, caffeine or other active components, or else flavoring. For instance, the aerosol-forming substance may comprise a tobacco material.

[17] In the following description, the aerosol generation device 1 is considered to be an electronic cigarette. But, as mentioned above the invention concerns any type of aerosol generation device.

[18] Moreover, in the following description, it will be considered that the aerosol-forming substance 4 is either in a liquid form (or state) (figures 1 , 4, 7 and 8), or in a solid form (or state) (figures 9 to 11). [19] It is also recalled that the term “aerosol” may include a suspension of substance as one or more of solid (very small) particles, liquid droplets and gas, and that such a suspension may be in a gas including air.

[20] As illustrated in figures 1 , 4 and 7 to 11 , an aerosol generation device 1, according to the invention, comprises at least an aerosol generation unit 2 and an airflow channel 3.

[21] The aerosol generation unit 2 is arranged for transforming an aerosol forming substance mixed with air into an aerosol that may be inhaled by a user through successive draws (or puffs or inhalation phases) during a vaping session.

[22] For instance, and as illustrated in the non-limiting examples of figures 1, 4, 7 and 8 (where the aerosol generation device 1 is an E-vapor device), the aerosol-forming substance 4 may be contained in an exchangeable cartridge (or capsule) 5 that may be manually replaced or refilled by the user when there is no more aerosol-forming substance in it. This exchangeable cartridge (or capsule) 5 can be installed manually, at least partly, into a dedicated cavity of the aerosol generation unit 2. As illustrated, an ending part 9 of the air flow channel 3 may, for instance, pass through the exchangeable cartridge (or capsule) 5 to collect the vaporized substance mixed with the air, originating from at least one inlet 10 of the air flow channel 3, and defining an aerosol. This ending part 9 comprises an outlet 11 for delivering the aerosol to the user when he is inhaling. In this example the ending part 9 is partly located outside the aerosol generation device 1 and its outlet 11 is temporarily located in the mouth of the user and used as a mouthpiece for inhaling the generated aerosol during each puff (or draw). But this ending part 9 could be connected to a mouthpiece. Thus, the air flow channel 3 extends from the at least one inlet 10 to the outlet 11 , and allows air, sucked by said user, to pass through a vaporization area 3a and to be mixed with said aerosol forming substance. In the case of the non-limiting examples shown in figures 1 , 4, 7 and 8 (where the aerosol generation device 1 is an E-vapor device), the vaporization area 3a lies between the at least one inlet 10 and the outlet 11 , within the dedicated cavity of the aerosol generation unit 2.

[23] In a variant of embodiment illustrated in the non-limiting examples of figures 9 to 11 where the aerosol generation device 1 is a T-vapor device, the aerosol-forming substance 4 is contained in a consumable 6 that may be manually replaced by the user when there is no more aerosol-forming substance in it. This consumable 6 can be installed manually, at least partly, into a dedicated cavity 7 of the aerosol generation unit 2 that may be a heating chamber. As illustrated, the dedicated cavity 7 communicates with an outlet 11 of the air flow channel 3 to be supplied with air originating from at least one inlet 10 of this air flow channel 3. Also as illustrated, the consumable 6 may comprise a filter 8, downstream of the aerosol-forming substance 4. As for a cigarette, the filter 8 may be partly and temporarily located in the mouth of the user and in this case it is used as a mouthpiece for inhaling the generated aerosol during each puff (or draw). In this way the consumable 6, when located within the cavity 7, forms an extension of the air flow channel 3, with a proximal end of the filter 8 constituting a mouthpiece outlet 11a. Thus, the air flow channel 3 extends from the at least one inlet 10 to the outlet 11 , and allows air, sucked by said user, to pass through a vaporization area 3a and to be mixed with said aerosol forming substance as it continues to the mouthpiece outlet 11a. In the case of the non-limiting examples shown in figures 9 to 11 (where the aerosol generation device 1 is a T-vapor device), the vaporization area 3a lies downstream of the at least one inlet 10 and the outlet 11 , within the dedicated cavity 7 of the aerosol generation unit 2.

[24] The aerosol-forming substance 4 is arranged for generating an aerosol when it is heated (without burning) and mixed with air. This heating is performed by a heater 12 supplied with electrical energy originating from a power source 13. This heater 12 belongs to the aerosol generation unit 2.

[25] In the non-limiting examples illustrated in figures 1 , 4, 7 and 8 the heater 12 surrounds the exchangeable cartridge (or capsule) 5 to heat the aerosol-forming substance 4. For instance, the heater 12 may be a coil associated with a susceptor or may be a resistive coil heater. In the first alternative, the coil is arranged for generating an electromagnetic field when it is supplied with an electrical current, and the susceptor is arranged for transforming this electromagnetic field into heat. In a variant of embodiment (not illustrated) the heater 12 could be located inside the exchangeable cartridge (or capsule) 5.

[26] In the non-limiting examples illustrated in figures 9 to 11 the heater 12 surrounds the heating chamber 7 and therefore the aerosol-forming substance 4. For instance, and as illustrated in the non-limiting examples of figures 9 and 10, the heater 12 may be a thin film heater wrapped around the outer surface of the heating chamber 8 to heat its side walls and at least a part of its internal volume. But in a variant illustrated in the non-limiting example of figure 11 the heater 12 may be a coil associated with a susceptor or may be a resistive coil heater. In the first alternative, the coil is arranged for generating an electromagnetic field when it is supplied with an electrical current, and the susceptor is arranged for transforming this electromagnetic field into heat. This susceptor may be a foil of a consumable 6 that surrounds or is located inside the aerosol forming substance 4.

[27] For instance, the heater 12 may heat the aerosol-forming substance 4 to a temperature comprised between 150°C and 350°C.

[28] The power source 13 is housed in a body 14 of the aerosol generation device 1. In the non-limiting examples illustrated in figures 9 to 11 , this body 14 comprises also the aerosol generation unit 2. But this is not mandatory. Indeed, as illustrated in the non-limiting examples of figures 1, 4, 7 and 8 the aerosol generation unit 2 can be housed in (or may comprise) another body coupled to the body 14 by screwing by means of two corresponding threaded portions, or by clipping or else by means of magnets, for instance. [29] Also for instance, the power source 13 may be a rechargeable battery. In this case the body 14 may comprise an electrical connector to which a charger cable may be connected during a charging session of the rechargeable battery 13. Such a charger cable may be coupled to an (AC) adapter or to a wall socket. The charger cable and/or the (AC) adapter may belong to the aerosol generation device 1.

[30] The electrical energy supplied to the heater 12 during a vaping session is controlled by a controller 15. This controller (or control unit) 15 may comprise at least a processor and a memory arranged for performing operations for controlling the aerosol generation unit 2 (and notably its heater 12) during a vaping session and also the power source 13 during a possible charging session.

[31] For instance, the processor may be a digital signal processor (or DSP), or an application specific integrated circuit (ASIC), or else a field programmable gate array (FPGA). More generally, the processor may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected therebetween through wired or wireless connections. The term “integrated (or printed) circuits” refers here to any type of device capable of carrying out at least one electric or electronic operation.

[32] Also for instance, the memory may be a random access memory (or RAM). But it may be any type of device arranged for storing program instructions for the processor.

[33] Generally speaking, the functions of the controller (or control unit) 15 may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually (by the user). These functions may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software.

[34] As illustrated in the non-limiting example of figure 1 , the controller (or control unit) 15 (and notably its processor and memory) may be fixed onto a printed circuit board (or PCB) 16 (here housed in the body 14). [35] The controller (or control unit) 15 may also comprise, in addition to its processor and memory, an input interface, a mass memory (notably for storing intermediate data produced during its calculus and processing), and an output interface for delivering messages and instructions at least for controlling the aerosol generation unit 2 (and notably its heater 12) and the electronic component(s) (such as switch(es)) supplying the electrical power (stored in the power source 13) to the aerosol generation unit 2.

[36] The air flow channel 3 allows the air, sucked by the user and originating from each inlet 10, to pass through and to be mixed with the aerosol-forming substance 4 in a vaporization area 3a of the air flow channel 3. This air flow channel 3 has an inner surface 17 and comprises at least one area 17a having an inner section d1 (specifically, an inner cross-sectional area d1) and comprising at least one flexible baffle 18 extending from the inner surface 17 on a part of the area 17a. This means that in each airflow channel area there is always a passage having at least a minimal section d2 (and specifically, a minimum cross-sectional area d2) to allow the air to pass through when there is no user suction.

[37] Each flexible baffle 18 is configured during a draw for deflecting when the draw pressure in its air flow channel area 17a exceeds a predetermined threshold to reduce the pressure drop between sub-areas located upstream and downstream of this air flow channel area 17a. The deflection of the flexible baffle(s) 18 has the effect of increasing the cross- sectional area of the airflow channel area 17a in which the baffle is located from the minimum cross-sectional area d2 to an increased section d3 (and, specifically, to an increased cross-sectional area d3). This permits an increase in the mean free air flow path through the air flow channel 3, which in turn causes the flow rate through the air flow channel 3 to increase, so reducing the total pressure drop between the at least one inlet 10 and the outlet 11 (and mouthpiece outlet 11a, if different).

[38] Examples of air flow channel areas 17a comprising at least one flexible baffle 18 without deflection are illustrated in figures 2 and 5. Examples of air flow channel areas 17a comprising at least one flexible baffle 18 deflected are illustrated in figures 3 and 6.

[39] The deformation occurs due to the higher fluid force impacting a first face 18a of the flexible baffle 18 receiving the air and the negative pressure recirculating vortex zone 19 formed downstream of this flexible baffle 18 just after its second face 18b (opposite to its first face). This deformation increases the mean free air flow path (or passage) in the air flow channel area, reducing the total pressure drop between the sub-areas located upstream and downstream of this air flow channel area. In other words when there is a deflection the passage section increases from 62 (minimal value) to d3 (> 62) as illustrated in figures 3 and 6. This allows to smooth out the pressure drop experienced by the user for various different suction strengths, and therefore ensures a more constant draw pressure experienced by the user when he increases or decreases his draw strength over time.

[40] In the examples illustrated in figures 2, 3, 5 and 6, each flexible baffle 18 can be thought of as a cantilever beam with a uniformly distributed load (here the suction pressure) across it. For instance, the deflection d along the beam may be modelled by the following equation: d = -(wx²/24EI)^*(6L² - 4Lx + x²), where w is the uniformly distributed load (suction pressure), x is the length along the flexible baffle 18, E is the Young’s modulus of the flexible baffle material, I is the second moment of inertia, and L is the length of the flexible baffle 18. It is important to notice that the above mentioned equation is given as an illustrative and simple example, because it assumes an ideal cantilever beam under ideal uniform distribution loads. So, this equation only aims at giving an idea of the loading case expected, but does not exactly describe the deflection.

[41] For instance, each flexible baffle 18 may be an insert that is attached fixedly to the inner surface 17 in an air flow channel area. But in a variant each flexible baffle 18 could be integral with the inner surface 17. Also for instance, each flexible baffle 18 may be made from a silicone elastomer or a flexible polymer.

[42] Preferably, each flexible baffle 18 is configured for having a deflection that varies with the difference between the draw pressure in its air flow channel area and the predetermined threshold. So, for high suction strength and therefore high flowrates the flexible baffle 18 deflects more to ensure that a very high pressure drop is not experienced, and for a low suction strength the flexible baffle 18 deflects very little (or does not deflect at all) and the pressure drop incurred by the flexible baffle 18 ensures that the experienced pressure drop is similar to the one experienced with a high suction strength.

[43] As illustrated in the non-limiting examples of figures 1 to 11 , each flexible baffle 18 may extend in a direction perpendicular to the extension axis 22 of its air flow channel area. But this is not mandatory. Indeed, a flexible baffle 18 could extend in a direction that is slightly different from this perpendicular direction.

[44] Also preferably, and as illustrated in figures 3 and 6, each flexible baffle 18 is configured for deflecting in the direction of the extension axis of its air flow channel area. To this effect each flexible baffle 18 has a predefined stiffness (Young’s modulus) ensuring that it deforms in the direction of the extension axis (or air flow direction) when an excessive draw pressure is experienced.

[45] As illustrated in the non-limiting examples of figures 1 , 4, 9 and 10, the air flow channel 3 may comprise only one inlet 10 and one outlet 11. But in a variant of embodiment illustrated in figures 7, 8 and 11 the air flow channel 3 may comprise at least two first sub-parts 20-1 and 20-2 each comprising an inlet 10 and a second sub-part 21 communicating with these first sub-parts 20-1 and 20-2 and comprising the outlet 11. Such an embodiment allows to have flexible baffles 18 in parallel in the first sub parts 20-1 and 20-2. [46] Also as illustrated in the non-limiting examples of figures 1 , 4, and 7 to 11 , the air flow channel 3 may comprise at least two areas each comprising at least one flexible baffle 18. But in a variant not illustrated the air flow channel 3 could comprise only one area comprising at least one flexible baffle 18.

[47] Also as illustrated in the non-limiting examples of figures 7, 8 and 11 , in the case where the air flow channel 3 comprises at least two first sub parts 20-1 and 20-2, each air flow channel area may belong to one of the first sub-parts 20-1 and 20-2. But this is not mandatory. Indeed, in a first variant of embodiment (not illustrated) each air flow channel area could belong to the second sub-part 21 , and in a second variant of embodiment (also not illustrated) each of the first 20-1 and 20-2 and second 21 sub parts could comprise at least one airflow channel area.

[48] Also as illustrated in the non-limiting examples of figures 1 , 7, 9 and 11 , in the case where the air flow channel 3 comprises at least two areas, at least two successive flexible baffles 18 may extend from opposite parts of the inner surface 17 and may belong to successive air flow channel areas separated therebetween by a chosen distance. This chosen distance between successive areas may possibly vary when the air flow channel 3 comprises at least three areas.

[49] But in a variant of embodiment illustrated in the non-limiting examples of figures 4 to 6, 8 and 10, at least one air flow channel area 17a may comprise two flexible baffles 18 arranged opposite to each other with a passage therebetween to allow air to pass through (without and with deflection). Without deflection the minimal value of the passage section is equal to d2. It should be noticed that when the air flow channel 3 comprises at least three successive areas (as illustrated), the distance therebetween may possibly vary.

[50] The advantage of using (multiple) pairs of inline or staggered flexible baffles 18 is the ability to more finely control the pressure drop by allowing for multiple different baffle lengths and possibly different materials to be used. This results in different degrees of deflection and pressure drop. So, it offers a smoother control of the pressure drop (a damping effect with multiple baffles). Moreover, the complex air flow path around these flexible baffles 18 may also help in filtering particles contained in the ambient air, and preventing them from reaching the aerosol generation unit 2.

[51] It should be appreciated by those skilled in the art that some block diagrams of figures 1 to 11 herein represent conceptual views of illustrative circuitry embodying the principles of the invention.

[52] It will be appreciated that alternative baffle structures are possible in addition to or as an alternative to the baffles shown in figures 1-11.

[53] For example, figures 12A and 12B illustrate an alternative air flow channel area 17a including a plurality of flexible baffles 18 at substantially the same axial location, which together co-operate to define a minimum cross sectional area d2 (FIG.12A) when undeflected and an increased cross-sectional area d3 (FIG. 12B) when deflected, where d2 < d3 < d1 (being the cross-sectional area of the airflow channel area in the absence of the flexible baffles). Each flexible baffle 18 of the example shown in figures 12A and 12B is curved, so as to present a concave first face towards the inlet and a corresponding concave second surface towards the outlet and the vortex zone 19. The example air flow channel area 17a in figures 12A and 12B includes three flexible baffles. Such a tricuspid valve may take less pressure to open than a bicuspid valve of similar size.

[54] Figures 13A and 13B illustrate a further alternative air flow channel area 17a including a flexible baffle having a generally helical or spiral shape, so as to present a spiral first face towards the inlet. The spiral baffle extends axially in the direction of the extension axis 22, and defines a minimum cross sectional area d2 (FIG.13A) when undeflected and an increased cross-sectional area d3 (FIG. 13B) when deflected, where d2 < d3 < d1 (being the cross-sectional area of the airflow channel area in the absence of the flexible baffles). In addition to permitting an increase in air flow rate in order to reduce the pressure drop through the air flow channel 3, as discussed above, such a spiral baffle may introduce some spiral flow into the air inhaled through the device, which may be beneficial for deposition of larger particles 23 in the device before they reach the user via centrifugal force. A spiral baffle of the type illustrated can be a single component and therefore may be easier to manufacture and assemble into the device than arrangements including multiple separate sequential baffles.

[55] Figures 14 and 15 illustrate further alternative helical baffles 18 located within an air flow channel 3. Each spiral baffle may be defined in terms of a pitch p, being the height of one complete helix turn, measured parallel to the axis of the helix, which here is parallel to the extension axis 22 of the air flow channel 3 in which the baffle is to be located. Where d1 is the air flow channel diameter and L is the baffle length protruding from the wall, then the pitch should preferably be in the range 0.5L < p < 5L, and the baffle length should be less than 0.5d1 , and should be preferably in the range 0.25d1 < L < 0.5d1. In the example shown in figure 14, the baffle length L = 0.453d1 and the pitch p = 0.735L. In the example shown in figure 15, the baffle length L =0.453d1 and the pitch p = 3.68L.

[56] The description and drawings merely illustrate the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.

Claims

1. Aerosol generation device (1 ) comprising: i) an aerosol generation unit (2) arranged for transforming an aerosol-forming substance (4) mixed with air into an aerosol that may be inhaled by a user through successive draws, and ii) an air flow channel (3) having an inner surface (17), at least one inlet (10) and an outlet (11), and allowing air, sucked by said user, to pass through a vaporization area (3a) and to be mixed with said aerosol-forming substance, wherein said air flow channel (3) comprises at least one area (17a) having an inner cross-section (d1) and comprising at least one flexible baffle (18) extending from said inner surface (17) and operable to reduce said inner cross-section of said area to a minimum cross- sectional area (d2), said at least one flexible baffle (18) configured during a draw for deflecting to increase said minimum cross-sectional area (d2) to an increased cross-sectional area (d3) when the draw pressure in said area exceeds a predetermined threshold to reduce a pressure drop between sub-areas located upstream and downstream of said area, wherein deflection of said at least one flexible baffle (18) is operable to increase a mean free air flow path between the at least one inlet (10) and the outlet (11 ).

2. Aerosol generation device according to claim 1, wherein the or each flexible baffle (18) is configured for having a deflection that varies with a difference between the draw pressure in said area and said predetermined threshold.

3. Aerosol generation device according to claim 1 or 2, wherein the or each flexible baffle (18) extends in a direction perpendicular to an extension axis of said airflow channel area.

4. Aerosol generation device according to any one of claims 1 to

3, wherein the or each flexible baffle (18) is configured for deflecting in a direction of an extension axis (22) of said air flow channel area.

5. Aerosol generation device according to any one of claims 1 to 4, wherein said air flow channel (3) comprises at least two first sub-parts

(20-1, 20-2) each comprising an inlet (10) and a second sub-part (21) communicating with said first sub-parts (20-1 , 20-2) and comprising said outlet (11).

6. Aerosol generation device according to any one of claims 1 to

5, wherein said air flow channel (3) comprises at least two areas (17a) each comprising at least one flexible baffle (18).

7. Aerosol generation device according to the combination of claims 5 and 6, wherein each airflow channel area (17a) belongs to one of said first sub-parts (20-1 , 20-2).

8. Aerosol generation device according to the combination of claims 5 and 6, wherein each airflow channel area (17a) belongs to said second sub-part (21 ).

9. Aerosol generation device according to the combination of claims 5 and 6, wherein each of said first (20-1 , 20-2) and second (21) sub-parts comprises at least one airflow channel area (17a).

10. Aerosol generation device according to any one of claims 6 to

9, wherein at least two successive flexible baffles (18) extend from opposite parts of said inner surface (17) and belong to successive air flow channel areas (17a) separated therebetween by a chosen distance.

11 . Aerosol generation device according to any one of claims 1 to

10, wherein at least one air flow channel area (17a) comprises two flexible baffles (18) arranged opposite to each other with a passage therebetween to allow air to pass through.

12. Aerosol generation device according to any one of claims 1 to 10, wherein at least one airflow channel area (17a) comprises a plurality of flexible baffles (18) together defining the minimum cross-sectional area (d2) when undeflected and operable to deflect to together define the increased cross-sectional area (d3).

13. Aerosol generation device according to claim 12, wherein each of said plurality of flexible baffles comprises a curved surface having a convex side presented towards said inlet (10).

14. Aerosol generation device according to any one of claims 1 to 10, wherein at least one flexible baffle defines a spiral surface.

15. Aerosol generation device according to any preceding claim, wherein said aerosol generation device (1) constitutes an electronic cigarette.