WO2022167583A1

WO2022167583A1 - An aerosol generating device, an aerosol generating system and a method for controlling the heating of such an aerosol generating device

Info

Publication number: WO2022167583A1
Application number: PCT/EP2022/052708
Authority: WO
Inventors: Alec WRIGHT
Original assignee: Jt International S.A.
Priority date: 2021-02-08
Filing date: 2022-02-04
Publication date: 2022-08-11

Abstract

An aerosol generating device comprises: - a heating chamber (3) mainly extending in an axial direction (X), bounded by an open end (4) through which an article (20) containing an aerosol substrate (21) is insertable and a bottom end (5) opposed to the open end (4); - detection means (10) configured to detect an axial position along the axial direction (X) of an end of the article (20) inserted in the heating chamber (3); - a plurality of heaters (8) for heating the aerosol substrate (21) of the article (20) in the heating chamber (3), arranged along the axial direction (X) of the heating chamber (3); and - a microcontroller (9) configured to activate only heaters (8) being located axially between the axial position of the end of the article (20) and the open end (4) of the heating chamber (3).

Description

An aerosol generating device, an aerosol generating system and a method for controlling the heating of such an aerosol generating device

Field of the invention

The present invention relates to an aerosol generating device. The invention is particularly applicable to a portable aerosol generating device. Such devices may heat, rather than bum, tobacco or other suitable materials by conduction, convection, and/or radiation, to generate an aerosol for inhalation

The present invention also relates to an aerosol generating system.

Furthermore, the present invention relates to a method for controlling the heating of an aerosol generating device.

Background of the invention

Various devices and systems are available that heat or agitate an aerosol substrate to produce an aerosol and/or vapour for inhalation, as opposed to burning tobacco as in conventional tobacco products.

One type of device is called heat-not-burn device. Devices of this type generate an aerosol and/or vapour by heating a solid aerosol substrate, typically moist leaf tobacco, to a temperature typically in the range 150°C to 300°C. Heating an aerosol substrate, but not combusting or burning it, releases an aerosol and/or vapour that comprises the components sought by the user but not the by-products of combustion and burning.

Aerosol generating devices of this type are thus portable devices comprising a heating chamber for receiving a stick containing an aerosol substrate and an electrical heater powered by a battery and controlled by a microcontroller, for heating the stick by conduction, convection and/or radiation. The power consumption is thus an important design consideration for this type of devices.

A stick looks like a traditional cigarette and includes a predetermined amount of aerosol substrate, a filter and a mouthpiece which mimics the feel of a traditional cigarette. Depending on the brands or the amount of aerosol substrate contained in the sticks, there are now sticks of different sizes, in particular of different lengths.

It might be desirable to make it possible to only heat a part of the stick, corresponding to the aerosol substrate.

For example, the document W02015/140312 discloses an aerosol generating device comprising separated heaters arranged along a cavity around an aerosol substrate. The heaters may be activated only if a sensor near an open end of the cavity senses the presence of the aerosol substrate. In this way the heaters are activated only when the aerosol substrate is in the cavity.

However, the aerosol generating device of W02015/140312 is only suitable for heating a single type of stick of predetermined size or with a fixed amount of aerosol substrate.

Summary of the invention

According to a first aspect of the invention, there is provided an aerosol generating device comprising: a heating chamber mainly extending in an axial direction, bounded by an open end through which an article containing an aerosol substrate is insertable and a bottom end opposed to the open end; detection means configured to detect an axial position along the axial direction of an end of the article inserted in the heating chamber; a plurality of heaters for heating the aerosol substrate of the article in the heating chamber, the heaters being arranged along the axial direction of the heating chamber; and a microcontroller configured to activate only heaters being located axially between the axial position of the end of the article and the open end of the heating chamber.

An article insertable in such an aerosol generating device may have different sizes and in particular different lengths. The length here is the distance between a mouth end intended to be placed in the mouth of a user and an insertable end opposite the mouth end, intended to be inserted into the heating chamber.

These different lengths may allow the article to contain different amounts of aerosol substrate. Thus, it is possible that the longer an article, the more aerosol substrate the article may contain, for example to suit the user needs.

Thus, by knowing the length of the part of the article inserted into the heating chamber, such a device is able to adapt the heaters activation depending on the amount of aerosol substrate contained in the article.

The temperature is set and adjusted easily since the number of activated heaters is reduced to a minimum depending on the amount of aerosol substrate. The distribution of power to the activated heaters is therefore also easier and requires less operations for the microcontroller. In addition, the activation heaters being located in front of the aerosol substrate allows faster heating of the aerosol substrate since the heat transfer is better between these heaters and the aerosol substrate.

Since the aerosol generating devices are mainly portable, their autonomy may be improved in cases where only part of the heaters is activated. Thus, the user of such an aerosol generating device may recharge it less frequently than a device in which all heaters are activated.

In addition, the user does not have to configure the aerosol generating device according to the amount of aerosol substrate contained in the article and inserted into the heating chamber.

According to one embodiment, the detection means comprise a base plate movable along the axial direction in the heating chamber, configured to contact the end of the article inserted into the heating chamber.

By contacting the end of the article inserted in the heating chamber, the base plate may provide the position of the article in the heating chamber along the axial direction. The base plate is also a simple, reliable and inexpensive solution for detecting the position of the article.

In addition, the base plate reduces the likelihood that any loose aerosol substrate fall from the article, which would result in dirtying of the heating chamber. In one embodiment, the detection means further comprise an elastic member connecting the base plate to the bottom of the heating chamber, the elastic member being configured to exert a force along the axial direction when it is compressed. It shall be understood that an elastic member is a component that uses its elastic properties, i.e. return to its original shape after being deformed, to absorb mechanical energy, produce movement or exert effort.

When the article is inserted in the heating chamber of the aerosol generating device, it pushes the base plate towards the bottom end of said heating chamber. Thanks to the elastic member, the base plate is pushed back against the article. Thus, the base plate may be closer to the article and allows to detect more precisely its axial position in the heating chamber.

According to one embodiment, the detection means further comprise a sensor connected to the microcontroller, the sensor being configured to measure the force transmitted by the elastic member when it is compressed.

The microcontroller may then determine the axial position of the aerosol substrate from the force detected by the sensor. The force may usually be produced when the article is inserted into the heating chamber and pushed towards the bottom end. That is, the force is created when the base plate is moved towards the bottom end of the heating chamber and the elastic member is compressed.

Thanks to this configuration, the axial position of the article in the heating chamber is detected by only one sensor. The integration of detection means in such an aerosol generating device only slightly affects the electrical power consumption. Moreover, the electrical power consumed by the sensor is much lower than the electrical power saved by activating some of the heaters instead of all the heaters.

In practice, the elastic member is a spring.

Advantageously, the spring does not require any electrical power supply, making it a power efficient solution. Furthermore, the axial position of the article in the heating chamber may be easily determined by the microcontroller once the parameters of the spring, for example its length or its stiffness, are known.

In one embodiment, the plurality of heaters are identical ring-shaped and arranged equidistant from each other along the axial direction, each heater of the plurality of heaters encircling the heating chamber.

In practice, the heaters are in number between 2 and 6 and have a width between 1 and 10 mm in the axial direction. This arrangement allows better adaptability of heating depending on the amount of aerosol substrate contained in the article and inserted into the heating chamber. In addition, the uniform distribution of heaters along the axial direction avoids less heated areas and allows uniform heating in the heating chamber.

According to one embodiment, the microcontroller is further configured to adapt the duration of activation of the heaters depending on the axial position of the end of article inserted into the heating chamber.

This configuration makes it possible to adapt the heating as well as possible, not by varying the location of the heating along the axial direction, but by varying its duration. In practice, the greater the amount of aerosol substrate, the longer the heaters are activated.

Consumption of the aerosol substrate is improved so that all of the aerosol substrate contained in the article is consumed. This also saves electrical power, for example when the article contains small amounts of aerosol substrate.

According to a second aspect, the present invention relates to a method for controlling the heating of an aerosol generating device as mentioned above, the method comprising, upon insertion of an article through the open end of the heating chamber, the steps of:

- determination by the detection means of an axial position of an end of the article in the heating chamber; and

- activation of heaters located between the axial position of the end of the article and the open end of the heating chamber.

The method for controlling the heating of an aerosol generating device has at least the same advantages as the aerosol generating device as mentioned above.

In one embodiment, wherein the detection means comprise a base plate movable along the axial direction in the heating chamber and an elastic member connecting the base plate to the bottom end of the heating chamber, the following step is performed before the step of determination of the axial position of the end of the article :

- detection by a sensor of a force exerted by the elastic member when it is compressed.

The advantages are the same as those described for the base plate previously.

In one embodiment, the following step is performed after the step of activation of the heaters:

- deactivation of the heaters after a predetermined heating timebased on the axial position of the end of the article in the heating chamber.

The advantages are identical to those described in connection with the configuration of the microcontroller to adapt the duration of activation of the heaters depending on the axial position of the article.

According to a third aspect, the present invention relates to an aerosol generating system comprising an aerosol generating device as previously described, and an article containing an aerosol substrate configured to be inserted in the heating chamber of the aerosol generating device.

The advantages are identical to those described for the aerosol generating device as mentioned above.

In one embodiment, the heating chamber and the article are cylindrical.

Thanks to this arrangement, the article may be inserted into the heating chamber (provided that its diameter is less than the diameter of the heating chamber) without a particular angular position. Thus, the use of the system by a user and in particular the insertion of the aerosol substrate into the heating chamber is facilitated.

In one embodiment, the heating chamber comprise a side wall exerting a frictional force along the axial direction on the article.

The article is held in position both axially and radially in the heating chamber, relatively to the axial direction. On the one hand, the article is held radially by resting against the side wall of the heating chamber and on the other hand it is held axially by the frictional force exerted by the side wall on the article.

In one embodiment, the detection means comprise a base plate movable along the axial direction in the heating chamber and an elastic member connecting the base plate to the bottom end of the heating chamber, the elastic member being configured to exert a force along the axial direction when it is compressed and the force exerted by the elastic member being less than the frictional force exerted by the side wall on the article.

When the article is inserted in the heating chamber of the aerosol generating device, the article pushes the base plate towards the bottom end of said heating chamber. Thanks to the elastic member, the base plate is pushed back against the article. Thus, the base plate may be closer to an end of the article in contact with the base plate and allows to detect more precisely its axial position in the heating chamber.

Due to the frictional force, the article is not ejected from the heating chamber by the force exerted by the elastic member. As a result, the elastic member allows via the base plate to compress the aerosol substrate of the article to reduce its length. This reduction in length by moving the base plate and compressing the aerosol substrate may reduce the number of heaters to be activated.

Brief description of the drawings

Other particularities and advantages of the invention will also emerge from the following description.

In the accompanying drawings, given by way of non-limiting examples:

- Figure 1 represents, in a schematic view, an aerosol generating device with an article according to a first embodiment of the invention;

- Figure 2 represents a schematic cross-sectional view from a side of the aerosol generating device of Figure 1 when no article is inserted in the aerosol generating device; - Figure 3A represents a schematic cross-sectional view from a side of the aerosol generating device of Figure 1 when an article is inserted in the aerosol generating device;

- Figure 3B represents a schematic cross-sectional view from a side of the aerosol generating device of Figure 1 when another article is inserted in the aerosol generating device; and

- Figure 4 represents a flowchart of steps implemented according to one embodiment of the invention.

Detailed Description

Referring to Figure 1 , according to a first embodiment of the invention, an aerosol generating device 1 comprises an outer casing 2 housing various components of the aerosol generating device 1 . The outer casing 2 has substantially a cuboid shape and may be formed of any suitable material, or layers of material. The shape and the material allow the outer casing 2 to be pleasant for a user to hold. Preferably, the outer case 2 of the aerosol generating device 1 is elongate, that is to say extend for a greater length than his width, along an axial direction (arrow X in Figures 1 to 3). Thus, the outer casing 2 has substantially a shape of parallelepiped rectangle as shown in Figure 1. However, edges and angles of the outer casing 2 may be rounded in order to be more peasant for a user. Of course, the outer casing 2 may be of any other shape as long as it allows the components to be housed and to be easily handled by the user. For example, the outer casing 2 may also has a shape of an elongated cylinder, like a pen.

Moreover, one face of the outer casing 2 is provided with an opening to access a heating chamber 3 of the aerosol generating device 1 . In this embodiment, it is one of the faces perpendicular to the axial direction X.

Indeed, the heating chamber 3 is configured to receive an article 20 containing an aerosol substrate 21 (see Figures 3A and 3B). In Figure 1 , the article is not received in the heating chamber 3.

The heating chamber 3 opens on one face of the outer casing 2 of the aerosol generating device 1. The opening on the outer casing 2 corresponds to an open end 4 of the heating chamber 3 through which the article 20 is receivable. The heating chamber 3 further comprises a bottom end 5 located inside the outer casing

2 and opposite the open end 4. In other words, the heating chamber 3 is a blind cavity at its bottom end 5.

As illustrated in Figure 2, the heating chamber 3 mainly extends along the length of the outer case 2, i.e. along the axial direction X. Thus, the heating chamber

3 is axially bounded by the open end 4 and the bottom end 5. The heating chamber 3 is radially bounded by a side wall 6 forming a substantially cylindrical profile. Thus, the heating chamber 3 has a substantially circular cross section and therefore a cylindrical profile. In this embodiment, the section of the heating chamber 3 is constant over its entire length. The length in this context being from the bottom end 5 to the open end 4 of the heating chamber 3.

In a non-illustrated embodiment, the aerosol generating device 1 may comprise a closure element arranged so as to be moveable between at least a closed position, in which the closure element obstructs the open end 4 so that material cannot enter into the heating chamber 3, and an open position, in which the open end 4 is uncovered to allow access to the heating chamber 3.

In the illustrated embodiment, the heating chamber 3 is dimensioned to receive the article 20 in the form of a cylinder as shown in Figure 1 . The dimensions of the heating chamber 3 are therefore slightly larger than the dimensions of the article 20.

A first end 22 of the article 20, illustrated in Figure 1 , is described for convenience as a mouth end of the article 20, by which the user vapes the aerosol. The first end 22 of the article 20 is intended for placement in the mouth of a user. Thus, the first end 22 remains protruding with respect to the outer casing 2 and outside the heating chamber 3 in order to be accessible to the user's mouth.

A second end 23 of the article 20, shown in Figure 1 , is described as an end to be inserted or an insertable end in the heating chamber 3. Typically, the article 20 contains a pre-packaged amount of aerosol substrate 21 such as tobacco or another suitable aerosolisable material that is heatable to generate an aerosol for inhalation. The amount of aerosol substrate 21 may be variable according to the needs of the user.

In a non-illustrated embodiment, the pre-packaged amount of aerosol substrate 21 may be formed of aerosol substrate portions, which are stackable to adjust the amount of aerosol substrate 21 contained in the article 20. The aerosol substrate portions may be distinct. When several aerosol substrate portions are stacked, they form a single portion of aerosol substrate 21. Such aerosol substrate portions may allow the amount of aerosol substrate 21 to be selected to suit the needs of a user of the aerosol generating device 1 .

Typically, the amount of aerosol substrate 21 contained in the article 20 affects the length of the article 20. The length of the article 20 is here described as the distance separating the first end 22 and the second end 23 of the article 20.

Referring to Figures 3A and 3B, the article 20 comprises a pre-packaged amount of the aerosol substrate 21 along with an aerosol treatment region 24 wrapped in an outer layer 25. The aerosol treatment region 24 of the article 20 typically comprises an aerosol cooling portion and a filter. The aerosol substrate 21 is located towards the second end 23 of the article 20. Moreover, the aerosol substrate 21 extends across the entire width or section of the article 20 within the outer layer 25.

The article 20 of Figure 3A contains an amount of aerosol substrate 21 less than that contained in the article 20 in Figure 3B. This difference in the amount of aerosol substrate 21 results in a difference in the length of the article 20. Therefore, the article 20 of Figure 3B containing an amount of aerosol substrate 21 greater than that of the article 20 of Figure 3A, has a greater length.

In the illustrated example, only the part of the article 20 containing the aerosol substrate 21 has a variable length depending of the amount of aerosol substrate 21 , the treatment region 24 has a constant length regardless of the amount of aerosol substrate 21 . The treatment part 24 of the article 20 is typically located on the side of the first end 22 of the article 20 and is not fully inserted into the heating chamber 3 so as to be accessible to the user's mouth.

Such an article 20 is slidably insertable in the heating chamber 3 of the aerosol generating device 1 along the axial direction X. The assembly of the article 20 in the aerosol generating device 1 forms an aerosol generating system 100, as shown in Figures 3A and 3B.

The aerosol generating system 100 may comprise axial stop means (not shown) preventing the introduction of the first end 22 of the article 20 inside the heating chamber 3. The corresponding cylindrical shape between the heating chamber 3 and the article 20 eliminates the need for a particular angular position. This makes it easier for the user to use, especially for insertion of the article 20 into the heating chamber 3.

However, this is not essential and the heating chamber s may receive the article 20 in other forms, such as loose tobacco or aerosol substrate 21 packaged in other ways.

It is also preferable that there is a frictional force when inserting the article 20 into the heating chamber 3. In other words, it is preferable that the aerosol generating system 100 forms a force-fitting assembly.

Such a frictional force between an inner surface of the side wall 6 of the heating chamber 3 and the outer layer 25 of the article 20 makes it possible to hold the article 20 in position inside the heating chamber 3. Preferably, the frictional force is parallel to the axial direction X since the article 20 is already held radially in position by the side wall 6. Thus, the frictional force makes it possible to ensure the axial retention of the article 20 along the axial direction X in the heating chamber 3.

In a non-illustrated embodiment, a plurality of protrusions may be formed in the inner surface of the side wall 6. The protrusions may extend towards and engage the article 20.

Further, in a configuration, the heating chamber s may be removable from the aerosol generation device 1. The heating chamber 3 may therefore be easily cleaned, or replaced.

In this embodiment, the opening on the outer casing 2 corresponding to the open end 4 of the heating chamber 3, is eccentric with respect to the width of the outer casing 2, i.e. along a direction perpendicular to the axial direction X. Thus, the heating chamber 3 is eccentric along the width of the outer casing 2.

On the one hand, the eccentric arrangement of the heating chamber 3 makes it easier for the user to use when he vapes. On the other hand, it leaves a bigger space to house an electrical power source 7, e.g. a battery.

Conversely, the heating chamber 3 may also be centered relative to the width of the outer casing 2. In this case, the components may be arranged around the heating chamber 3 so as to evenly distribute the masses.

In the case where the outer casing 2 is cylindrical (i.e. pen-shaped) the heating chamber is centered along the main axis of the cylinder and the components are arranged side by side along the axial direction X.

In order to heat the aerosol substrate 21 of the article 20, the heating chamber 3 is surrounded by a plurality of heaters 8.

Indeed, the aerosol generating device 1 further comprises a plurality of heaters 8 for heating the inside of the heating chamber 3. Each heater 8 extends around the heating chamber 3. In more detail, the heaters 8 extend around the side wall 6 of the heating chamber 3. In order to evenly heat the interior of the heating chamber s, the heaters 8 are arranged along the axial direction X around the heating chamber 3. Moreover, the heaters 8 extend all the way around the side wall 6, but only over part of the length of the heating chamber 3. This part preferably comprises the lower part of the heating chamber 3, that is to say on the side of the bottom end 5. It is not always necessary that the heaters 8 extend over all the length of the heating chamber 3 since most of the articles 20 comprises aerosol substrate 21 only on part of their length, as shown in Figures 3A and 3B.

As a variant, the heaters 8 may also extend over the entire length of the side wall 6 of the heating chamber 3.

The heaters 8 are preferably placed end to end, without spacing, in the axial direction X.

In the embodiment in which the pre-packaged amount of aerosol substrate 21 contained in the article 20 is formed by several stackable portions, it is preferable that each heater 8 has a length in the direction of the axial direction X substantially equal to the length of an aerosol substrate portion. In this way, each heater 8 is dedicated to heating an aerosol substrate portion. This makes it easy to adjust the heating of the aerosol substrate 21 contained in each portion as best as possible.

In practice, the heaters 8 are in number between two and six. Preferably, the heaters 8 are in number of four. Further, each heater 8 has a width between 1 and 10 mm in the axial direction X. Preferably, each heater 8 has a width of about 5 mm in the axial direction X. Of course, the width of each heater 8 is given by way of example and could for example be between 2 and 8 mm, more particularly between 3 and 7 mm, and even more particularly between 4 and 6 mm. The number of heaters 8 is also given as an example since it depends on the height of the heating chamber 3 but also on the width of the heaters 8.

It will be understood that the heaters 8 of the illustrated example are provided on an external surface of the side wall 6, outside of the heating chamber 3. The heaters 8 are provided in good thermal contact with the heating chamber 3, to allow a good transfer of heat between the heaters 8 and the heating chamber 3.

It should be noted that heat losses necessarily lead to a greater consumption of electrical power to obtain a sufficient quantity of heat inside the heating chamber 3 while compensating for these heat losses. Consequently, the material as well as the thickness of the side wall 6 of the heating chamber 3 are chosen so as to minimize heat losses.

Each heater 8 is powered by the electrical power source 7 of the aerosol generating device 1 . The electrical power source 7 is located in the space left inside the outer casing 2, due to the eccentric position of the heating chamber 3. This allows the electrical power source 7 to be spaced away from the heaters 8, which are located around the heating chamber 3 of the aerosol generation device 1 . Moreover, each heater 8 is coupled to a microcontroller 9, which is coupled to the electrical power source 7. The microcontroller 9 is configured to control the electrical power supplied by the electrical power source 7 to each heater 8. Therefore, the microcontroller 9 is configured to activate, deactivate or control the temperature of each heater 8 independently. The microcontroller 9 is also configured to measure the heating time of each heater 8 and to deactivate a heater 8 after a predetermined heating time of continuous or discontinuous heating.

The microcontroller 9 is provided inside the outer casing 2 and is positioned towards a face of the outer casing 2, preferably opposite to the face on which the heating chamber 3 opens. As for the electric power source 7, it is preferable that the microcontroller 9 is away from the heaters 8. The microcontroller 9 and the electrical power source 7 may also be thermally insulated by material or layers of material well known in the field of thermal insulation.

However, the length of the wiring (not shown) for the coupling of the microcontroller 9 to the heaters 8 and to the electrical power source 7, may affect the consumption of electrical power, in particular by causing losses by the joule effect. In order to reduce these losses and thus the electrical power consumption, the microcontroller 9 is disposed substantially halfway between the heaters 8 and the electric power source 7 to limit the length of the wiring.

In order to further reduce the electrical power consumption, the microcontroller 9 is configured to activate only the heaters 8 located in front of the article 20 or the part of the article 20 inserted in the heating chamber 3. Therefore, the presence of the article 20 in the heating chamber 3 of the aerosol generating device 1 constitutes an area in the heating chamber 3. As shown in Figures 3A and 3B, the area has a variable length along the axial direction X, depending on the amount of aerosol substrate 21 contained in the article 20 inserted into the heating chamber 3.

Such an area necessarily extends from the open end 4 of the heating chamber 3, since the article 20 is insertable only through the open end 4, to the second end 23 of the article 20. Thus, the area is axially delimited by the open end 4 and an axial position corresponding to the position of the second end 23 of the article 20 in the heating chamber 3. This axial position of the second end 23 of the article 20 is between the open end 4 and the bottom end 5 of the heating chamber 3.

Depending on the length of the article 20 or of the amount of aerosol substrate 21 to be inserted into the heating chamber 3, it is advantageous for the electrical power consumption to activate only heaters 8 capable of heating the aerosol substrate 21 as efficiently as possible. In other words, it is advantageous to activate only the heaters 8 in front of the part of the article 20 that contains the aerosol substrate 21.

In order to achieve this, the aerosol generating device 1 comprises detection means 10 configured to detect the axial position of the article 20 along the axial direction X in the heating chamber 3. More precisely, the detection means 10 are configured to detect the axial position of the second end 23 of the article 20 which is inserted into the heating chamber 3.

When the axial position detected by the detection means 10 is equal to the position of the open end 4 of the heating chamber 3, nothing is inserted into the heating chamber 3. In this case, no heater 8 needs to be activated.

Conversely, when the axial position detected by the detection means 10 is equal to the axial position of the bottom end 5 of the heating chamber 3, activation of all heaters 8 is required to heat the area occupied by the article 20.

When the axial position is between the open end 4 and the bottom end 5 of the heating chamber 3 as illustrated in Figure 3A or 3B, only the area between the open end 4 and the detected axial position need to be heated. In other words, only the heaters 8 located between the open end 4 of the heating chamber 3 and the axial position detected by the detection means 10 are activated. In the example illustrated in Figure 3A, only the heater 8 closest to the open end 4 of the heating chamber 3 is activated. In Figure 3A, the three heaters 8 closest to the open end 4 of the heating chamber 3 are activated.

As a reminder, the axial position detected by the detection means 10 corresponds to the axial position of the second end 23 of the article 20 in the heating chamber 3 along the axial direction X.

Consequently, the microcontroller 9 is configured to activate only heaters 8 being located axially between the axial position of the second end 23 of the article 20 and the open end 4 of the heating chamber 3. In this way, only the heaters 8 being axially located in the area occupied by the article 20 are activated by the microcontroller 9. This allows to activate only heaters 9 which can heat the aerosol substrate 21 as efficiently as possible, by adapting to the amount of aerosol substrate 21 contained in the article 20.

In the illustrated embodiment, the detection means 10 comprise a base plate 11 movable in translation along the axial direction X in the heating chamber 3.

The base plate 11 is configured to contact the article 20 in the heating chamber 3 in order to detect the axial position of the article 20. More precisely, the base plate 11 is configured to contact the second end 23 of the article 20 inside the heating chamber 3.

As a reminder, the article 20 is insertable only through the open end 4 of the heating chamber 3. The article 20 is slidably insertable from the open end 4 towards the bottom end 5 of the heating chamber 3.

In this embodiment, the base plate 11 is configured to be pushed towards the bottom end 5 of the heating chamber 3 by the article 20. In order to best detect the axial position of the second end 23 of the article 20 in the heating chamber 3, it is preferable that the base plate 11 is in contact with the second end 23 of the article 20 from the start of insertion into the heating chamber 3. Thus, when no article is inserted into the heating chamber 3, the base plate 11 is located at the open end 4 of the heating chamber 3, as shown in Figure 2.

Further, the base plate 11 is configured to remain inside the heating chamber 3. In this way, the base plate 11 may serve as a cover for protecting the heating chamber 3 of the aerosol generating device 1 from dirt or dust for example.

In addition, the base plate 11 prevents the aerosol substrate 21 from falling from the second end 23 of the article 20 into the heating chamber 3, which would result in dirtying of the heating chamber s. Therefore, it is preferable that the base plate 11 has substantially the same section as the heating chamber 3 at the open end 4.

Further, it is preferable that the base plate 11 is thin to not absorb too much heat. The base plate 11 preferably has a thickness of less than 1 mm. Of course, the thickness of the base plate 11 is given by way of example and could for example be between 1 and 3 mm. The base plate 11 is made from the same material as the heating chamber 3, namely stainless steel. Any other material resistant to the temperatures mentioned above is possible.

Preferably, the base plate 11 is positioned so that its surface configured to contact the second end 23 of the article 20 is aligned with the face of the outer casing 2 when no article 20 is inserted as illustrated in Figure 2. Thus, the base plate 11 is in an initial position when no force is applied to it by an article 20, located at the open end 4 of the heating chamber 3.

In this embodiment, the detections means 10 further comprise an elastic member 12 connecting the base plate 11 to the bottom end 5 of the heating chamber 3.

The term “elastic member” should be understood to mean any component made of elastically deformable material, able to absorb mechanical energy, produce movement, or exert force or torque.

Although the area in which the elastic member 12 is located (i.e. between the base plate 11 and the bottom end 5 of the heating chamber 3) is not heated, the elastic member 12 may however be made from materials resistant to temperatures up to 500°C for example.

When the base plate 11 is pushed by the article 20 towards the bottom end 5 of the heating chamber 3, the elastic member 12 is compressed. Preferably, the elastic member 12 works in compression, i.e. once compressed, it provides a force to restore its initial length.

The force exerted by the elastic member 12 is substantially parallel to the axial direction X.

Thus, when the base plate 11 is movable and the elastic member 12 is compressed, the force pushes the base plate 11 towards the open end 4 of the heating chamber 3 until it reaches its original length.

Otherwise, the elastic member 12 is configured to no longer exert force when the base plate 11 is at the open end 4 of the heating chamber 3, i.e. at its initial position. More precisely, the initial length of the elastic member 12 is predetermined so that it allows the base plate 11 to be located at the open end 4 of the heating chamber 3 when no force is applied.

In this way, the base plate 11 remains in the heating chamber 3 and the elastic member 12 allows to bring it back to its initial position.

As a variant, the heating chamber 3 may comprise instead or in addition of the predetermined initial length of the elastic member 12, an axial abutment to prevent axial displacement of the base plate 11 outside the heating chamber 3.

When the article 20 is inserted into the heating chamber 3, the elastic member 12 is compressed and the base plate 11 is not movable towards the open end 4 of the heating chamber 3. Consequently, the elastic member 12 exerts a force at its ends, i.e. on the base plate 11 and on the bottom end 5 of the heating chamber 3.

Thanks to the properties of the elastic member 12 and the force it exerts, it is generally possible to determine its displacement in the axial direction X. Therefore, it is possible to determine the axial position of the second end 23 of the article 20 in the heating chamber 3.

In the illustrated embodiment, the elastic member 12 is a spring with predetermined properties such as initial length and/or spring stiffness. For example, the spring 12 may have an initial length equal to the length of the heating chamber 3 imputed by the thickness of the base plate 11 along the axial direction X. Further, the stiffness of the spring 12 may be predetermined so that the force to push the article 20 into the heating chamber 3 is not too great for a user but allows enough pressure on the article 20 to compress the aerosol substrate 21 and thus have a more precise axial position of the second end 23 of the article 20 in the heating chamber 3. As shown in Figures 2,3A and 3B, the spring 12 is cylindrical. The diameter of the spring 12 is chosen large enough so that the base plate 11 remains stable, that is to say moves in the heating chamber 3 while remaining substantially parallel to the surface of the bottom end 5 of the heating chamber 3.

Of course the cylindrical shape of the spring 12 is not limited and a wide variety of shapes are possible such as conical shape in order to completely compress the spring for example.

In the case where the elastic member 12 is a spring, the axial position of the second end 23 of the article 20 in the heating chamber 3 is given by the following formula:

F

^X ~ k where k refers to the stiffness of the spring 12 and F refers to the force exerted by the spring at one of its ends.

Thus, the detection means 10 further comprise a sensor 13 configured to measure the force transmitted by the spring 12 at one of its ends. More generally, the detection means 10 comprise a sensor 13 configured to measure the force F transmitted by the elastic member 12.

The sensor 13 is positioned at one end of the elastic member 12. Preferably, the sensor 13 is positioned at the end of the elastic member 12 connected to the bottom end 5 of the heating chamber 3. This arrangement allows the sensor 13 to be close to the microcontroller 9 and thus reduces the length of the wiring for the same reasons explained previously.

Indeed, the sensor 13 is connected to the microcontroller 9 and transmits a signal of an intensity corresponding to the measured force exerted by the elastic member 12. The microcontroller 9 is then configured to receive and process such a signal in order to determine the axial position of second end 23 of the article 20 in the heating chamber 3. Of course, the predetermined properties of the elastic member 12 are previously loaded into a memory of the microcontroller 9.

A correlation table between axial position values and the heaters 8 to be activated may also be loaded into the memory of the microcontroller 9. In this way, the microcontroller 9 is able to activate the corresponding heaters 8 depending on the axial position of the second end 23 of the article 20 in the heating chamber 3. In other words, the microcontroller 9 can activate the corresponding heaters 8 depending on the amount of aerosol substrate 21 contained in the article 20.

Furthermore, the correlation table also includes a predetermined heating time associated with each axial position value. Thus, the microcontroller 9 is further configured to adapt the duration of activation of the heaters 8 depending on the axial position of the second end 23 of the article 20 in the heating chamber 3.

In the following, a method for controlling the heating of the aerosol generating device 1 is described with reference to Figure 4.

During an insertion step S300, the article 20 containing an aerosol substrate 21 is inserted into the heating chamber 3 of the aerosol generating device 1 , as illustrated by Figures 3A and 3B. More precisely, the article 20 is slidably inserted along the axial direction X through the open end 4 of said heating chamber 3. The article 20 is inserted until only part of the article 20 on the side of the first end 22 remains outside the heating chamber 3, as shown in Figures 3A and 3B. This part protrudes from the surface of the outer casing 2 and allows the user to vape by putting it in his mouth.

The aerosol generating device 1 , the article 20, or both may comprise axial stop means (not shown) so as to prevent the introduction of this part on the side of the first end 22 of the article 1 into the heating chamber 3.

During insertion, the second end 23 of the article 20 is in contact with the base plate 11 . The user exerts a force on the article 20 in order to insert it into the heating chamber 3, towards the bottom end 5 of the heating chamber 3 and along the axial direction X.

As a reminder, the aerosol generating system 100 forms a force-fitting assembly. In other words, the side wall 6 of the heating chamber 3 is configured to exert a frictional force on the article 20. During insertion of the article 20, the force exerted by the user overcomes the frictional force exerted by the side wall 6 on the article 20.

The base plate 11 being initially positioned at the open end 4 of the heating chamber 3, is pushed towards the bottom end 5 of the heating chamber 3 by the article 20 until only the part on the side of the first end 22 of the article 20 remains outside the heating chamber 3.

Therefore, the elastic member 12 is compressed between the base plate 11 and the bottom end 5 of the heating chamber 3. The elastic member 12 then exerts a force at its ends, which depends on the axial position of the base plate 11 in the heating chamber 3. In practice, the more the elastic member 12 is compressed, the greater the force exerted by the elastic member 12.

However, the elastic member 12 is chosen so that the force it exerts remains less than the frictional force exerted by the side wall 6 of the heating chamber 3 on the article 20. Thus, the article 20 is not ejected from the heating chamber 3 and the force exerted by the elastic member 12 remains constant.

Once the article 20 has been inserted into the heating chamber 3, in order to know the force exerted by the elastic member 12, the sensor 13 measures the force in a detection step S301 .

Once the force is measured, the sensor 13 sends a signal of an intensity corresponding to the measured force to the microcontroller 9 to which it is connected to.

The axial position of the second end 23 of the article 20 in the heating chamber 3 is then determined by the microcontroller 9 during a determination step S302. Knowing the value of the force exerted by the elastic member 12 and the predetermined parameters of the elastic member 12 previously loaded on a memory of the microcontroller 9, the axial position of the second end 23 of the article 20 in the heating chamber 3 is determined by the microcontroller 9.

Once the axial position of the article 20 in the heating chamber 3 has been determined, it is compared with values of axial position loaded into a memory of the microcontroller 9. The axial position values are for example grouped in a correlation table and associated with heaters 8 to be activated to heat the aerosol substrate 21 contained in the article 20.

Depending on the heaters 8 associated with the corresponding axial position value, the microcontroller 9 activates the corresponding heaters 8 during an activation step S303. In this way only the heaters 8 being in front of the aerosol substrate 21 of the article 20 are activated in order to reduce the electrical power consumption and to better control the heating of the aerosol substrate 21.

In addition to the heaters 8 associated with axial position values, predetermined heating time values are also associated for the activation of these heaters 8. The predetermined heating time values for activation of the heaters 8 are also loaded into a memory of the microcontroller 9 and is preferably included in the correlation table.

Generally, the larger the amount of aerosol substrate 21 contained in the article 20, the greater the heating time of the heaters 8.

However, the axial position of the second end 23 of the article 20 may not correspond to a position in which an integer number of heaters 8 is in front of the article 20. In other words, it is possible that the second end 23 of the article 20 is axially located in the middle of a heater 8.

In this case, only the heaters 8 which are completely in front of the article 20 are activated. In order to compensate the non-activated heater 8, the heating time of the heaters 8 in front of the article 20 is increased. Of course, the axial position values and the associated predetermined heating times corresponding to this case are included into the correlation table loaded in the memory of the microcontroller 9.

Once the heaters 8 are activated, it is determined in a heating time reaching step S304 whether the heating time for the activation of the heaters 8 has been reached.

It should be noted that the activation of the heaters 8 is not necessarily continuous. The predetermined heating time may be decremented in several times.

For example, during a smoking session the user takes several puffs, making interruptions between each puff. The aerosol generating device 1 may comprise a sensor for detecting the user aspiration or a button activable by the user for manually activating the heaters 8. Thus, the heaters 8 may be activated only when the user is vaping. Consequently, the activation of the heaters 8 during a predetermined heating time may correspond to a continuous or discontinuous activation of the heaters 8 for a cumulative duration equal to the predetermined heating time.

When the predetermined heating time has elapsed, the heaters 8 are deactivated during a deactivation step S305. Once this predetermined heating time is reached, it is no longer possible to activate the heaters 8 without having renewed the aerosol substrate 21.

Thanks to the invention, an improved aerosol generating device may be provided, with detection means for adapting the heating according to the amount of aerosol substrate introduced into the heating chamber.

Thanks to the detection means, it is possible to activate only the heaters having the best efficiency to heat the aerosol substrate. Thus, it is possible to reduce the electrical power consumption and therefore to increase the autonomy of the aerosol generating device compared to devices activating all the heaters by detecting only the presence of an article in the heating chamber.

It is then easier to regulate the heating of the aerosol substrate due to the activation of a smaller number of heaters and the good heat transfer between these heaters and the aerosol substrate.

The method for controlling the heating of the aerosol generating device provides the same advantages as the device and allows operation that is simple to implement and does not require a lot of electrical power.

List of references:

1 : aerosol generating article

2 : outer casing

3 : heating chamber

4 : open end 5 : bottom end

6 : side wall

7 : electrical power source

8 : heater 9 : microcontroller

10 : detections means

11 : base plate

12 : elastic member

13 : sensor 20 : article

21 : aerosol substrate

22 : first end

23 : second end

24 : aerosol treatment region 25 : outer layer

100 : aerosol generating system

Claims

25 CLAIMS

1. An aerosol generating device comprising :

- a heating chamber (3) mainly extending in an axial direction (X), bounded by an open end (4) through which an article (20) containing an aerosol substrate (21) is insertable and a bottom end (5) opposed to the open end (4);

- detection means (10) configured to detect an axial position along the axial direction (X) of an end of the article (20) inserted in the heating chamber (3);

- a plurality of heaters (8) for heating the aerosol substrate (21) of the article (20) in the heating chamber (3), arranged along the axial direction (X) of the heating chamber (3); and

- a microcontroller (9) configured to activate only heaters (8) being located axially between the axial position of the end of the article (20) and the open end (4) of the heating chamber (3).

2. The aerosol generating device according to Claim 1 , wherein said detection means (10) comprise a base plate (11) movable along the axial direction (X) in the heating chamber (3), configured to contact the end of the article (20) inserted in the heating chamber (3).

3. The aerosol generating device according to Claim 2, wherein said detection means (10) further comprise an elastic member (12) connecting the base plate (11) to the bottom end (5) of the heating chamber (3), the elastic member (12) being configured to exert a force along the axial direction (X) when it is compressed.

4. The aerosol generating device according to Claim 3, wherein said detection means (10) further comprise a sensor (13) connected to the microcontroller (9), the sensor (13) being configured to measure the force transmitted by the elastic member (12) when it is compressed.

5. The aerosol generating device according to Claims 3 or 4, wherein said elastic member (12) is a spring.

6. The aerosol generating device according to any one of Claims 1 to 5, wherein said plurality of heaters (8) are identical ring-shaped and arranged equidistant from each other along the axial direction (X), each heater (8) of the plurality of heaters (8) encircling the heating chamber (3).

7. The aerosol generating device according to any one of Claims 1 to 6, wherein the heaters (8) are in number between 2 and 6 and have a width between 1 and 10 mm in the axial direction (X).

8. The aerosol generating device according to any one of Claims 1 to 7, wherein said microcontroller (9) is further configured to adapt the duration of activation of the heaters (8) depending on the axial position of the end of the article (20) inserted into the heating chamber (3).

9. A method for controlling the heating of an aerosol generating device (1) according to any one of Claims 1 to 8, said method comprising, upon insertion of an article (20) through the open end (4) of the heating chamber (3), the steps of :

- determination (S302) by the detection means (10) of the axial position of an end (23) of the article (20) in the heating chamber (3); and

- activation (S303) of heaters (8) located between the axial position of the end (23) of the article (20) and the open end (4) of the heating chamber (3).

10. The method for controlling the heating according to Claim 9, wherein the detection means (10) comprise a base plate (11) movable along the axial direction (X) in the heating chamber (3) and an elastic member (12) connecting the base plate (11) to the bottom end (5) of the heating chamber (3), the following step is performed before the step of determination (302) of the axial position of the aerosol substrate (21) :

- detection (S301) by a sensor (13) of a force exerted by the elastic member (12) when it is compressed.

11 . The method for controlling the heating according to Claim 9 or 10, wherein the following step is performed after the step of activation (303) of the heaters (8) :

- deactivation (S305) of the heaters (8) after a predetermined heating time based on the axial position of the end (23) of the article (20) in the heating chamber (3).

12. An aerosol generating system comprising an aerosol generating device (1) according to Claims 1 to 8, and an article (20) containing an aerosol substrate (21) configured to be inserted in the heating chamber (3) of the aerosol generating device (1).

13. The aerosol generating system according to Claim 12, wherein the heating chamber (3) and the article (20) are cylindrical.

14. The aerosol generating system according to Claim 13, wherein said heating chamber (3) comprise a side wall (6) exerting a frictional force along the axial direction (X) on the article (20).

15. The aerosol generating system according to Claim 14, wherein the detection means (10) comprise a base plate (11) movable along the axial direction (X) in the heating chamber (3) and an elastic member (12) connecting the base plate (11 ) to the bottom end (5) of the heating chamber (3), the elastic member (12) being configured to exert a force along the axial direction (X) when it is compressed and the force exerted by the elastic member (12) being less than the frictional force exerted by the side wall (6) on the article (20).