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Title:
AEROSOL-GENERATING DEVICE COMPRISING A MEMS VAPOR GENERATION UNIT AND A FILTER
Document Type and Number:
WIPO Patent Application WO/2023/052469
Kind Code:
A1
Abstract:
The invention relates to an aerosol-generating device (1) comprising a vapor generation unit (5) adapted to transform an aerosol forming material into vapor, the vapor generation unit (5) comprising a micro electro-mechanical system (MEMS), a reservoir (2) configured to store an aerosol forming material and a filter module (12) comprising a filter (13) disposed so as to remove particles from said aerosol forming material passing from said reservoir (2) towards the vapor generation unit (5). The filter module (12) is removable from the aerosol-generating device (1 ) to be cleaned or exchanged. If clogging of the filter occurs, the filter can be changed or cleaned, allowing a long-term use of the aerosol-generating device (1).

Inventors:
WRIGHT ALEC (GB)
ROGAN ANDREW ROBERT JOHN (GB)
Application Number:
PCT/EP2022/077050
Publication Date:
April 06, 2023
Filing Date:
September 28, 2022
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
JT INT SA (CH)
International Classes:
A24F40/10; A24F40/48; A24F40/85
Foreign References:
EP3157587A12017-04-26
EP2172239A22010-04-07
US20200008473A12020-01-09
CN113424996A2021-09-24
US20200008473A12020-01-09
Attorney, Agent or Firm:
SANTARELLI (FR)
Download PDF:
Claims:
CLAIMS

1. Aerosol-generating device (1) comprising:

- a vapor generation unit (5) adapted to transform an aerosol forming material into vapor, the vapor generation unit (5) comprising a micro electro-mechanical system (MEMS),

- a reservoir (2) configured to store an aerosol forming material; and

- a filter module (12) comprising a filter (13) disposed so as to remove particles from said aerosol forming material passing from said reservoir (2) towards the vapor generation unit (5), wherein the filter module (12) is removable from the aerosol-generating device (1) to be cleaned or exchanged.

2. Aerosol-generating device (1) according to claim 1 , wherein it has an elongated shape along a main axis of extension (X), and the filter (13) extends in a plane transverse to this main axis.

3. Aerosol-generating device (1 ) according to claim 1 or claim 2, wherein the filter module (12) is removable from the rest of the aerosol-generating device by translation of the filter module in a direction perpendicular to a main axis of extension of said aerosol generating device.

4. Aerosol-generating device (1) according to any one of the preceding claims, wherein the filter (13) comprises a mesh.

5. Aerosol-generating device (1 ) according to claim 4, wherein the mesh is made of stainless steel.

6. Aerosol-generating device (1 ) according claim 4 or claim 5, wherein the mesh has a porosity lower than 50% and preferably equal to 34%.

7. Aerosol-generating device (1) according to any one of the preceding claims, wherein the filter module (12) comprises a housing, the filter (13) being incorporated in the housing. 8. Aerosol-generating device (1) according to any one of the preceding claims, wherein it comprises a slot (14) for insertion and removal of the filter module (12).

9. Aerosol-generating device (1) according to any one of the preceding claims, wherein it comprises a release mechanism configured such that the actuation of the release mechanism results in the release of the filter module for removal from the aerosol-generating device (1).

10. Aerosol-generating device (1) according to claim 9, wherein the actuation of the release mechanism is performed by pressing on a dedicated push-button.

11. Aerosol-generating device (1) according to claim 9, wherein the actuation of the release mechanism is performed by sliding a release command.

12. Aerosol-generating device (1) according to claim 9, wherein the release mechanism is configured to be actuated only by an adapted tool.

13. Aerosol-generating device (1) according to claim 12, wherein the release mechanism is configured to be actuated only by a pin tool (15).Aerosol-generating device (1) according to any one of the preceding claims, wherein it comprises a capsule of aerosol forming material as reservoir (2) and the filter module is interposed between the capsule and the vapor generation unit (5), the filter module (12) being in fluidic communication with said capsule and with said vapor generation unit (5).

14. Aerosol-generating device (1) according to claim 13, wherein the capsule comprises a pad (18) of porous material at the outlet of the capsule, thereby forming a first filtration stage of aerosol forming material before it reaches the filter (13).

15. Aerosol-generating device (1) according to claim 14, wherein the pad (18) is made of cotton.

Description:
Aerosol-generating device comprising a MEMS vapor generation unit and a filter

Field of the invention

The present invention relates to an aerosol-generating device.

An aerosol-generating device allows aerosolization of an aerosol-forming material. An aerosol-generating device can also be referred to a vapor generation device.

Background of the invention

An aerosol-generating device generally comprises a battery-powered vapor generation unit which produces an aerosol from a vaporizable material to be inhaled by a user. Where the vaporizable material is a liquid, a usual configuration of a vapor generation unit comprises a resistive heating element arranged to heat a wick element soaked with liquid vaporizable material.

Alternative vapor generation units are known, that use a microfluidic device. Such microfluidic vapor generation unit corresponds to a so-called “micro electro-mechanical system”, also designated by the acronym “MEMS”. MEMS technology can be defined as miniaturized mechanical and electro-mechanical elements that are made using micro fabrication techniques. MEMS technology may also referred to as microsystem technology (MST).

Document US2020008473 discloses for instance an electronic cigarette comprising a MEMS. The MEMS used in the vapor generation unit comprises at least one microfluidic structure, called a MEMS die. MEMS dies comprise a series of small chambers, each containing a heater therein.

Advantages of aerosol-generating devices using a microfluidic vapor generation unit or more generally a micro electro-mechanical system include small size, compact structure, lower power consumption, lower cost, increased reliability and higher precision, and high heat transfer efficiency.

Because of their small dimensions, MEMS dies are prone to be clogged by any impurity present in the fluid passing through them. More generally, any dust or impurity present in the fluid which passes through the MEMS die may degrade its operation and I or damage it.

For this reason, a filter may be associated to the MEMS die to remove particles from a liquid vaporizable material delivered to the MEMS die of vapor generation unit before vaporization thereof.

For example, document US2020008473 discloses a vaporizer head for an electronic cigarette product, comprising a wick structure assembly for supplying a MEMS heating element with a vaporizable liquid contained in a reservoir. The wick structure comprises a filter layer.

The filtration of the liquid vaporizable material (i.e. of the aerosol forming product) constitutes a relevant protection for a MEMS die. However, the filter, which must be very fine to effectively protect the MEMS die, is itself easily clogged. A filter clogging blocks the passage of the liquid vaporizable material or at least greatly increases the pressure drop generated by the filter, making the aerosol-generating device using such MEMS die potentially unusable.

The present invention thus aims to provide an aerosol-generating device comprising a vapor generation unit comprising a MEMS, which addresses one or several of the above-mentioned problems. Summary of the invention

The present invention thus relates to an aerosol-generating device comprising a vapor generation unit adapted to transform an aerosol forming material into vapor, the vapor generation unit comprising a micro electro-mechanical system (MEMS). The aerosol-generating device comprises a reservoir configured to store an aerosol forming material. The aerosol-generating device comprises a filter module comprising a filter arranged to remove particles from said aerosol forming material passing from the at least one reservoir towards the vapor generation unit. According to the invention, the filter module is removable from the aerosolgenerating device to be cleaned or exchanged.

The invention thus allows effective protection of the MEMS system (in particular of the MEMS system allowing the vaporization of the aerosol forming material), while ensuring that the aerosol-generating device remains usable for a long time, even in the event of clogging of the filter. The filter module including a filter may consist of the filter or may include a filter and other parts (e.g., a filter retaining frame). The filter module may comprise a housing and a filter incorporated in the housing. Depending on the nature and configuration of the filter module, cleaning or replacing the filter makes it possible to place a clean, unclogged and undamaged filter back into the aerosol-generating device.

The aerosol-generating device may have an elongated shape along a main axis of extension, and the filter may extend in a plane transverse to this main axis.

This is a simple device configuration. It also makes it possible to provide for an extraction of the filter module in the transverse direction (perpendicular to the direction of extension of the aerosol-generating device), through a lateral face of the aerosol-generating device. For instance, the filter module may be removable from the rest of the aerosol-generating device by translation of the filter module in a direction perpendicular to the main axis of extension of said aerosol generating device.

More particularly, the aerosol-generating device may comprise a slot for insertion and removal of the filter module.

The aerosol-generating device may comprise a release mechanism configured such that the actuation of the release mechanism results in the release of the filter module for removal from the aerosol-generating device.

For example, the actuation of the release mechanism may be performed by pressing on a dedicated push-button. According to another example, the actuation of the release mechanism is performed by sliding a release command.

The release mechanism may be configured to be actuated only by an adapted tool. For example, the release mechanism may be configured to be actuated only by a pin tool.

When the aerosol-generating device comprises a slot for insertion and removal of the filter module and a release mechanism that may be actuated by a pin tool, the system for receiving and retaining the filter module in the aerosol-generating device can therefore be similar to the system that is employed in most smartphones for inserting, retaining and removing the SIM card. Such a system is compact, reliable, easy to use, and does not require complex developments.

The filter module may be located adjacent to the vapor generation unit.

This provides maximum protection for the MEMS system. In addition, this makes it possible to constitute an aerosol-generating device in which the functional distribution between the storage of the product forming an aerosol and the vaporization of the product is clearly distinct. It is thus easily possible to design an aerosol-generating device with an interchangeable reservoir, for example with a reservoir in the form of a capsule. The aerosol-generating device may thus comprise a capsule of aerosol forming material and the filter module can be interposed between the capsule and the vapor generation unit, the filter module being in fluidic communication with said capsule and with said vapor generation unit.

The capsule may comprise a pad of porous material at the outlet of the capsule, thereby forming a first filtration stage of the aerosol forming material before it reaches the filter. The pad can may be made of cotton.

This enhances the filtration of the aerosol generating material and limits the occurrence of the filter changes or filter cleaning.

The filter may comprise a mesh. The mesh may be made of stainless steel. The mesh may have a porosity lower than 50% and preferably equal to 34%.

Many constitutions are possible for the filter of the filter module. The filter may be a grid. It may be textile. It may in particular be formed of interlaced or noninterlaced (woven or non-woven, knit or non-knit) fibers.

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 three-dimensional view, an aerosolgenerating device according to an embodiment of the invention;

- Figure 2 represents, in a schematic three-dimensional view, an example of a vapor generation unit that can be used in the invention;

- Figure 3 represents, in a schematic diagram, an aerosol-generating device according to an embodiment of the invention with its filter module in place; - Figure 4 represents, in a schematic diagram, an aerosol-generating device according to an embodiment of the invention with its filter module removed.

Detailed Description

Figure 1 represents schematically part of an aerosol-generating device 1 according to an embodiment of the invention. The device is normally covered with a casing omitted here to show the inner parts of the aerosol-generating device.

The aerosol-generating device 1 comprises a reservoir 2. The reservoir 2 is arranged to store an aerosolizable material, also called aerosol-forming material. The term aerosol-forming material is used to designate any material that is aerosolizable in air to form an aerosol. The aerosol-forming material may, for example, be in liquid form (usually called e-liquid), in solid form, or in a semi liquid form. The aerosol-forming material thus comprises or consists of an aerosolgenerating liquid, gel, paste or wax or the like, or any combination of these. E-liquid is mostly a mix of water, propylene glycol (PG), and vegetable glycerine or glycerol (VG).

The reservoir 2 can form an exchangeable and/or refillable capsule (also called cartridge). The reservoir 2 comprises one or several volumes (e.g. tubes) containing the aerosol forming material. For example, the reservoir 2 forms a removable component that can be detached from the aerosol-generating device 1 (such as when the reservoir is empty of liquid). For example, the reservoir provided as a capsule can be fixed in a removable way to a capsule holder of the aerosol generating device. However, the reservoir can alternatively be permanently installed in the aerosol-generating device if it is configured to be refillable.

The aerosol-generating device 1 comprises a battery 3 or any power supply unit adapted to supply power to electronic components of the device, in particular to a vapor generation unit comprising a MEMS die (not shown in Figure 1).

The battery 3 is for example connected to a main printed circuit board 4 of the aerosol-generating device. The main printed circuit board 4 constitutes the main support structure for various elements of the aerosol-generating device.

The aerosol-generating device 1 also comprises a vapor generation unit

5, shown in Figure 2, arranged to aerosolize the product received from the reservoir in order to generate aerosol.

More particularly, Figure 2 represents an example of a vapor generation unit that is particularly adapted to be used in the embodiment of Figure 1 .

The vapor generation unit 5 comprises a micro-electro-mechanical- system, also commonly called MEMS. The represented vapor generation unit comprises two microfluidic structures or MEMS dies 6. According to embodiments of the invention, the vapor generation unit can comprise one or several MEMS dies

6. Use of a plurality of vapor generation units can help produce a sufficient quantity of aerosol and/or provide a large aerosol production surface to obtain a homogeneous aerosol.

The vapor generation unit shown in Figure 2 is integrated into a printed circuit board, also named here secondary printed circuit board 7 or daughter board.

The two MEMS dies 6 are fastened, e.g. soldered, to the secondary printed circuit board 7.

Each MEMS die 6 presents an upper surface 8, on the upper surface of the vapor generation unit 5.

On the opposite side of the secondary printed circuit board 6, the vapor generation unit 5 comprises two inlet ports 9. Each inlet port 9 is configured to be flu id ical ly connected to an inner volume of the reservoir 2 of the aerosol-generating device.

The MEMS dies 6 comprise a series of small chambers, each containing a heater therein.

The most significant advantage of MEMS is their ability to communicate easily with electrical elements in semiconductor chips. Other advantages include small size, compact structure, lower power consumption, lower cost, increased reliability and higher precision, and high heat transfer efficiency.

In the present invention, the aerosolization does not involve a phase change from the aerosolizable material to gas. It generally creates an aerosol using thermal firing chambers. The working principle is similar for example to that of thermal inkjet functioning. The aerosolizable material droplets are ejected from at least one MEMS die by applying a pulse of pressure to the material supplied in the chambers of the MEMS die.

To create this pressure pulse, the “thermal inkjet” principle can be applied as follows. The aerosol forming material is heated by the heater of the at least one MEMS die until it starts to boil and a gas bubble is created. The gas bubble is comprised of a phase change of the aerosol forming material, usually liquid, and potentially air trapped in the liquid. The amount of the aerosol forming material boiled is about 1 % of the total amount. In other words, around 1 % of the aerosol forming material is superheated to form a gas bubble. This 1 % consists of the amount of aerosol forming material that is the closest to the heater. A same quantity of a component being more voluminous in gaseous form than in liquid form, it provides the force to push out aerosol forming material from the vapor generation unit. This allows approximately 80-90% of the aerosol forming material above the gas bubble to be ejected.

Gas bubbles grow as they are heated until they are large enough that they force out liquid droplets to be ejected. The gas bubbles also escape when the liquid droplets are ejected. This creates a vacuum which causes more liquid to be drawn into the vapor generation unit 5 from the reservoir 2. The process then repeats.

It shall be noted that the propylene glycol (PG) and the vegetable glycerine (VG) that may be present in the aerosol forming material may possibly not vaporize as boiling points of these components are higher than the boiling point of water at the same atmospheric pressure. However, without being bound by theory because the high temperature’s heater, it is considered thatall of the aerosol forming material near the heater, regardless of composition, is superheated and undergoes the phase change to the gas bubble. In other words, the 1 % amount of the aerosol forming material that is superheated can be made up of a mixture of components that is similar to that of the rest of the aerosol forming material.

The aerosol-generating device 1 further comprises a mouthpiece 10 having an aerosol outlet 11 . The mouthpiece 10 consists of the portion from which a consumer inhales the aerosol.

The aerosol-generating device 1 thus comprises an aerosol flow path extending from the vapor generation unit 5, and arranged to fluidically communicate with the mouthpiece 10 and with the aerosol outlet 11 to allow the generated aerosol to flow from the vapor generation unit 5 to the mouthpiece 10 and to be inhaled by a user of the aerosol generating device.

The aerosol flow path, which may also be referred to as an airflow path of the aerosol-generating device, is thus a channel through which air flows substantially in a direction towards the mouthpiece when a consumer draws upon the mouthpiece.

In the embodiment of the invention represented in Figure 1 , the aerosolgenerating device has an elongated shape along a main axis of extension (X). The mouthpiece 10 is located at one end of the aerosol-generating device 1. The reservoir 2 is located under the vapor generation unit 5 when the aerosol generating device is in the use position. Use position shall mean the position in which is put the aerosol generating device when ready for use or being used, namely the position in which the mouthpiece 7 is upwards.

The aerosol generating device of the invention also comprises a filter module 12, comprising a filter 13 or formed by the filter 13 (shown in Figures 3 and 4).

The filter 13 is configured to remove particles from the aerosol forming material passing from the reservoir 2 to the vapor generation unit 5.

The filter 13 is thus fluidically connected on the one side to the reservoir 2, and on the other side to the vapor generation unit 5.

The filter module and filter 13 can have various configurations. The filter 13 can comprise for example a mesh. The mesh is preferably made of a stainless- steel material. The mesh can be a Dutch twill weave. The mesh count can be for example of 400 x 2800, and the mesh thickness 0.067 mm. Preferably, the mesh has a low porosity. In particular, the porosity of the mesh is preferably lower than 50%, for example equal to 34%.

The filter can for example be configured to remove any particle of 3 pm or more, or of 1 .5 pm or more from the aerosol-generating material that flows through the filter.

According to the present invention, the filter module can be removed or extracted, from the rest of the aerosol-generating device 1. To this end, and as represented in Figure 1 , the aerosol generating device can comprise a slot 14.

The filter module 13 can be inserted into the slot 14 where it is held when the aerosol generating device is in use. The aerosol generating device is thus advantageously provided with a release mechanism. The release mechanism is a mechanism that is configured such that its actuation results in the release of the filter module for removal from the aerosol-generating device, e.g. from the slot 14.

The actuation of the release mechanism can be performed in embodiments of the invention by pressing on a dedicated push-button, or by sliding a release command. According to other embodiments an adapted actuation tool can be required to actuate the release mechanism.

The release mechanism can be adapted to be actuated by a pin tool 15. A pin tool 15 is a tool comprising an elongate pin that can be inserted into a small hole 16 situated near the slot 14 to actuate the release mechanism. Such mechanism and pin tool are used in most smartphones to release the SIM card.

Figure 3 represents an aerosol-generating device according to an embodiment of the invention with its filter module in place. The schematic diagram of Figure 3 is a simplified sectional view of the aerosol-generating device 1.

Figure 3 shows more particularly a possible arrangement of:

- the housing 17 of the aerosol generating device;

- the main circuit board 4;

- the succession, along the main axis of extension (X) of: the battery 3, the reservoir 2, the filter module 12, the secondary circuit board 7 comprising the vapor generation unit 5;

- the mouthpiece 10.

In Figure 3, the filter module is in place in the housing of the aerosol generating device. The slot through which the filter module is introduced is not visible in this figure because it is closed for example by a suitable door.

The filter module and the filter extend orthogonally to the main axis of extension (X) of the aerosol generating device. In the represented embodiment, the filter module is situated adjacent to the outlet of the reservoir 2. A fluidic connection or liquid channel 19 is arranged to transport the filtered aerosol forming material to the vapor generation unit 5.

In the embodiment of Figure 3, the outlet of the reservoir 2 (i.e. of the capsule in this embodiment) is provided with a pad 18. The pad 18 is formed of a porous material, such as cotton, and forms a first stage of filtration.

The filtration carried out by the pad 18 is coarser than that carried out by the filter 13, but it makes it possible to avoid sudden clogging of the filter 13 by particles of relatively large dimensions. For example, the pad 18 can retain all particles having a diameter of the order of 10 pm or more.

In Figure 4, the filter module 12 is removed from the rest of the aerosolgenerating device. The aerosol-generating device 1 of Figure 4 is the same as the aerosol-generating device shown in Figure 3, and thus the above description of Figure 3 applies to Figure 4.

The filter module 12 has been removed from the rest of the aerosolgenerating device by translation of the filter module in a direction perpendicular to the main axis of extension (x). Figure 4 further show the chamber 20 accommodated by the slot 14 for receiving the filter module 12.

The chamber 20 is in fluidic communication with the reservoir 2 and with the liquid channel 19. The chamber is configured such that, when the filter module 12 is in place within the chamber 19, the aerosol forming material must flow through the filter 13 to reach the vapor generation unit 5.

It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be covered by the appended claims. The present invention thus provides an aerosol-generating device comprising a vapor generation unit benefiting from the advantages provided by the MEMS technology while protecting the MEMS die from damages and malfunction and enabling a long-term use of this device.

References used for the figures