EP4287860A1

EP4287860A1 - An aerosol-generating device comprising a filter

Info

Publication number: EP4287860A1
Application number: EP22704345.2A
Authority: EP
Inventors: Alec WRIGHT; Andrew Robert John ROGAN; Kyle ADAIR; Gordon MONTGOMERY
Original assignee: JT International SA
Current assignee: JT International SA
Priority date: 2021-02-04
Filing date: 2022-02-02
Publication date: 2023-12-13
Also published as: WO2022167486A1; US20240099382A1; CA3207340A1

Abstract

The invention, relates an aerosol-generating device comprising a vapor generation unit (20), at least one reservoir (33) configured to store an aerosol forming material (34), and a filter (22) disposed so as to remove particles from said aerosol forming material (34) passing from said at least one reservoir (33) to the vapor generation unit (20), the vapor generation unit (20) comprising a micro electromechanical system (MEMS). The aerosol-generating device (1) is characterized in that the filter (22) is configured to heat the aerosol forming material (34) passing through it.

Description

An aerosol-generating device comprising 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 as an electronic cigarette or vapor generation device.

Background of the invention

An aerosol-generating device generally comprises a battery-powered vapor generation unit which produces the aerosol that is inhaled. For this purpose, many vapor generation unit have been designed in prior art, among which microfluidic devices or more generally units comprising a micro-electro-mechanical- system (MEMS). Document US2020008473 discloses for instance an electronic cigarette comprising a MEMS.

The MEMS technology can be defined as miniaturized mechanical and electro-mechanical elements that are made using the techniques of micro fabrication. MEMS technology is also referred to as microsystem technology (MST) in Europe.

The vapor generation units comprising a MEMS present many advantages, in particular in size and power consumption. However, aerosolgenerating devices comprising such a vapor generation unit do not usually produce warm aerosol as the aerosol forming material does not undergo phase changes before vaporization. Therefore, the produced aerosol is at ambient temperature or as low as 1 ° Celsius above the ambient temperature. This is because a small amount of the aerosol forming material goes through a phase change during aerosol generation and gets heated to boiling point. Inhaling a cold aerosol could be odd for the consumer who generally enjoys inhaling warm aerosol.

Therefore, the present invention aims at improving the user experience by providing an aerosol-generating device comprising a vapor generation unit comprising a MEMS and capable of producing warm aerosol without increasing the size of the aerosol-generating device and in a cost-efficient way.

Summary of the invention

The present invention thus relates to an aerosol-generating device comprising a vapor generation unit, at least one reservoir configured to store an aerosol forming material, and a filter disposed so as to remove particles from said aerosol forming material passing from said at least one reservoir to the vapor generation unit, the vapor generation unit comprising a micro electro-mechanical system (MEMS).

According to the invention, the filter is configured to heat the aerosol forming material passing through it.

In other words, the filter is configured to heat the aerosol forming material passing through it without the use of a separate heater. For example, the filter can comprise a portion configured to heat the aerosol forming material passing through it. In another example, the entire filter can be configured to heat the aerosol forming material passing through it. As a non-limiting example, said portion or the entire filter can be configured to be resistively heated. Said otherwise, said portion or the entire filter can be made of a conductor able to produce heat by Joule heating.

Thanks to this configuration, the aerosol forming material is filtered and heated in the same time. This way, there is no need to add a separate element, namely a heater, in the aerosol-generating device, in order to produce warm vapor since the filter itself is used to heat the aerosol forming material.

This presents thus the advantage of providing warm vapor to the consumer of a vapor generation unit type aerosol-generating device in an easy, inexpensive and compact way. Moreover, heating the aerosol forming material before its passage into the vapor generation unit helps improving the user experience.

According to an embodiment, micro electro-mechanical system of the vapor generation unit comprises at least one MEMS die.

According to one embodiment, the filter is located adjacent to the vapor generation unit.

Preferably, the filter is located adjacent to said at least one MEMS die.

According to one embodiment, the filter is located below the vapor generation unit in a longitudinal direction of the aerosol-generating device when the aerosol-generating device is in a use position.

Preferably, the filter is located below said at least one MEMS die.

According to one embodiment, the filter is in contact with or almost in contact with the vapor generation unit.

Preferably, the filter is in contact with or almost in contact with said at least one MEMS die.

Thanks to these features, temperature drop of the aerosol forming material before it reaches the vapor generation unit is reduced as much as possible. According to one embodiment, the filter comprises a mesh, preferably made of stainless-steel material. According to one embodiment, the filter comprises at least one wire configured to heat all or part of the rest of the filter by conduction when power is applied to said at least one wire.

This configuration enables the heating of the filter in an easy and efficient way.

According to one embodiment, said at least one wire of the filter extends through the mesh.

According to one embodiment, said at least one wire is embedded in the mesh.

According to one embodiment, said at least one wire is in contact with at least 30% of a lateral surface of the mesh, preferably at least 50%, and more preferably 60% of a lateral surface of the mesh.

According to one embodiment, said at least one wire is a resistance wire adapted to convert electrical energy into heat when power is applied to it.

According to one embodiment, said at least one wire is heated by an external heating source, such as a resistive heater.

According to one embodiment, the aerosol-generating device comprises an induction coil configured to inductively heat said at least one wire.

According to one embodiment, the mesh has a porosity lower than 50% and preferably equal to 34%.

This improves the heating of the aerosol forming material passing through the filter. Indeed, thanks to the low porosity, a high surface to volume ratio is ensured in the filter and the aerosol forming material is this way in contact with a large heated surface. According to one embodiment, the aerosol-generating device comprises a battery configured to directly heat the filter.

According to one embodiment, the filter is heated so as to bring the aerosol forming material to a temperature ranging between 50°C to 100°C.

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 is a partial schematic cross-sectional view of an aerosolgenerating device according to an embodiment of the invention;

- Figure 2 represents, in a schematic three-dimensional view, an aerosol-generating device according to a second example embodiment of the invention;

- Figure 3a represents, in a schematic three-dimensional view, an example vapor generation unit that can be used in the invention; and

- Figure 3b represents in a cross-sectional diagram a portion of an example of an aerosol-generation device comprising a vapor generation unit that can be used in the invention.

Detailed Description

Figure 1 represents schematically part of an aerosol-generating device 1 according to one embodiment of the invention.

An aerosol-generating device generally comprises a main body 2 and a cartridge 3. Only part of the body 2 is represented on the figure. The cartridge 3 comprises a first end 30 configured to engage with the body 2 and a second end 31 arranged as a mouthpiece portion having an aerosol outlet 32.

The cartridge 3 further comprises at least one reservoir 33. The reservoir is arranged to store an aerosol forming material 34 also named aerosolizable material 34. In the represented embodiment, the cartridge 3 comprises two reservoirs 33.

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 (called e-liquid), in solid form, or in a semi liquid form, thus comprise or consist of an aerosol-generating 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 33 forms a removable component that can be detached from the aerosol-generating device 1 (such as when the reservoir is empty of liquid). However, the reservoir can also be permanently installed on the aerosol-generating device if it is configured to be refillable.

The reservoir 33 can be, by way of example, a one-piece plastic part, for example obtained by injection molding.

The cartridge 3 also comprises an aerosol flow path 35 extending from the body 2 and arranged to fluidically communicate with the mouthpiece 31 to allow the generated aerosol to flow from the body 2 to the mouthpiece 31. The aerosol flow path extends here between the two reservoirs 33.

The aerosol flow path 35, which may also be referred to as an airflow channel, is a channel through which air flows substantially in a direction A (represented on the figure) towards the mouthpiece 31 when a consumer draws upon the mouthpiece 31. In other words, the airflow channel is arranged to transport generated aerosol to the mouthpiece through which the aerosol is inhaled by a consumer. In the represented embodiment, the aerosol flow path 35 is a central tube that is mainly formed by the reservoir 33. The aerosol flow is represented by arrows.

The cartridge 3 can be entirely or partly removable and replaceable.

The body 2 comprises a power supply unit or battery, other functional electrical components and connecting elements configured to connect with the cartridge 3. These components and elements are not represented on the figure.

The body 2 also comprises a vapor generation unit 20 arranged to aerosolize the material received from the reservoir and generate an aerosol.

The vapor generation unit 20 comprises a micro-electro-mechanical- systems (MEMS). The vapor generation unit 20 is integrated to a printed circuit board (not shown on the figure) of the aerosol-generating device.

The MEMS comprises at least one microfluidic structure, called a MEMS die. MEMS dies 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.

The MEMS vapor generation unit 20 has a first surface 21 that faces toward the aerosol flow path 35 of the aerosol-generating device. In other words, the aerosol flow path extends from the MEMS vapor generation unit 20 towards the mouthpiece 31.

In an embodiment, the aerosol-generating device 1 may comprise more than one vapor generation unit 20. Use of a plurality of vapor generation units can help producing a sufficient quantity of aerosol and/or to provide a large aerosol production surface to obtain a homogeneous aerosol.

In the present invention, the aerosolization doesn’t involve a phase change from the aerosol forming material to gas. It generally creates an aerosol using thermal firing chambers. The working principle is similar for example to that of the thermal inkjet functioning. The aerosol forming 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, “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 being 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. Gas being much more voluminous than liquid, it provides the force to push out from the vapour 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 being large enough that they force 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 20 from the reservoir 33. 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 not vaporize as boiling points of these components are higher than the boiling point of water at the same atmospheric pressure. However, because the high temperature’s heater, it is very possible that all 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 body 2 further comprises a filter 22 connected on the one side to the at least one reservoir 33 and on the other side to the vapor generation unit 20. In the represented embodiment, the filter 22 is fluidically connected to the two reservoirs 33 by liquid channels 23. The aerosol-generating device 1 comprises here two liquid channels 23.

The filter 22 is configured to remove particles from the aerosol forming material 34 passing from the reservoirs to the vapor generation unit.

The filter 22 comprises a body. The body is 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 of 0,067 mm. Preferably, the mesh has a low porosity. In particular, the porosity of the mesh is lower than 50%, for example equal to 34%. Such a low porosity provides a high surface area to volume ratio to the filter 22.

The aerosol-generating device 1 is configured to heat the filter 22.

In an embodiment, the filter 22 comprises at least one wire (not shown on the figures) adapted to heat the filter 22. Preferably, the filter 22 comprises a plurality of wires.

In an embodiment, the wires can form part of the body of the filter 22.

In another embodiment, the wires can cover at least partially the body of the filter. Preferably, the wires are in direct contact with the body of the filter 22. The wires are thus adapted to heat the body of the filter 22 by conduction.

Preferably, the wires cover or form a sufficient amount of surface of the body of the filter to enable a good heat of the filter. The wires are in contact with or form at least 30% of a surface of the body of the filter, preferably at least 50%, and more preferably 60%.

The wires can be woven around the body of the filter 22 or be part of the body of the filter 22.

In another embodiment, the wires are embedded within the body of the filter 22. The wires can be in such a case in contact with an internal surface of the filter 22.

The wires can consist of many thin wire strands, individually insulated. The wires can be twisted or woven together.

For example, the wires of the filter 22 extend through the stainless-steel mesh.

The wires can be resistance wires adapted to convert electrical energy into heat when power is applied to them. In a different embodiment, the wires may be heated by an external heating source, such as a resistive heater. In another embodiment, the wires may be inductively heated.

In yet another embodiment, the filter 22 may be directly heated, without the use of wires. The filter 22 can be heated by means of the battery of the aerosolgenerating device.

The filter 22 is preferably adjacent to the vapor generation unit 20. Adjacent shall mean directly in contact with or almost in contact with. In other words, the distance separating the filter 22 from the vapor generation unit 20 is very small or inexistent so as to ensure that the aerosol forming material 34 exiting the filter at a certain temperature arrives to the vapor generation unit 20 substantially at the same temperature. In the represented embodiment, the vapor generation unit 20 and the filter 22 are in a facing arrangement in the longitudinal direction of the aerosol generating device. In particular, the filter 22 extends below the vapor generation unit 20 when the aerosol generating device is in a 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 31 is upwards.

The filter 22 can be directly integrated to the printed circuit board with the vapor generation unit 20.

Figure 2 represents an aerosol-generating device according to a second example embodiment of the invention. The device of Figure 2 is normally covered with a casing omitted here to show the inner parts of the aerosol-generating device.

In this embodiment, the aerosol-generating device has an elongated shape. The mouthpiece 31 is located at one extremity of the aerosol-generating device. The at least one reservoir 33 is located under the vapor generation unit 20 when the aerosol generating device is in the use position. In this example, the aerosol-generating device also comprises two reservoirs 33 formed. The reservoirs 33 comprise two distinct hollow tubes.

Figure 2 shows a battery 4 and a main printed circuit board 5 (PCB). The battery 4 is fastened to the main printed circuit board 5 of the aerosol-generating device. The main printed circuit board 5 constitutes the main support structure for the various elements of the aerosol-generating device.

Figure 3a represents an example of vapor generation unit that is particularly adapted to be used in the example embodiment of Figure 2. The vapor generation unit 20 comprises here two microfluidic structures or MEMS dies 200. The two MEMS dies 200 are fastened, e.g. soldered, to a printed circuit board 201.

Each MEMS die 200 has an upper surface 202. The two upper surfaces 202 are coplanar and thus form the upper surface of the vapor generation unit 20.

On the opposite side of the printed circuit board 201 , the vapor generation unit 20 comprises two inlet ports 203. Each inlet port 203 is configured to be fluidically connected to an inner volume of the reservoir 33 of the aerosolgenerating device.

In operation, the aerosol forming material 34 is drawn from the reservoirs into the filter 22. The aerosol forming material 34 then travels into and through the vapor generation unit 20 for instance by capillary action.

Thanks to power supplied by the battery, the filter 22 is heated. In particular, the wires of the filter 22 are configured to heat all or part of the rest of the filter 22 by conduction when power is applied to the wires. In turn, the filter 22 heats the aerosol forming material 34 passing through it.

Therefore, thanks to this configuration, there is no need to use a separate heater to heat the aerosol forming material 34.

The hot aerosol forming material 34 then exists the filter 22 to pass through the vapor generation unit 20. The vapor generation unit 20 finally transforms the aerosol forming material 34 into aerosol.

The aerosol generated by the vapor generation unit 20 enters the airflow channel 35 of the aerosol-generating device and travels to the mouthpiece 31.

Thanks to this configuration, the aerosol generated by the aerosolgenerating device 1 is warm.

Figure 3b represents in a cross-sectional diagram a portion of an example of an aerosol-generation device comprising in a different configuration a vapor generation unit 20. The vapor generation unit 20 of figure 3b is similar to that of figure 3a and is also particularly adapted to be used in the embodiment of figure 1.

The vapor generation unit 20 also comprises here two microfluidic structures or MEMS dies 200. Each MEMS die 200 of the vapor generation unit 20 has an upper surface or vaporization surface 202. The vapor generation unit 20 is in fluid communication with two fluidic connections or liquid channels 23 each of which is arranged to transport the liquid aerosol forming material from the reservoir 33 to the vapor generation unit 20. Each liquid channel 23 is connected to a MEMS die 200 through an inlet port 203. Liquid aerosol forming material is drawn from each liquid channel 23 to a MEMS die 200 by capillary force.

Two aerosol flow paths 35 are arranged here to fluidly communicate with the mouthpiece of the aerosol-generating device. Each aerosol flow path 35 allows thus the generated aerosol to flow from a MEMS die 200 of the vapor generation unit 20 to the mouthpiece. n other words, the aerosol flow paths 35 connect air inlets (not shown) within the aerosol-generating device to the mouthpiece for the passage of air through the aerosol-generating device.

A downstream end of each aerosol flow path 35 forms a nozzle 36. The nozzles 36 and the vaporization surfaces 202 are usually on parallel planes. In other words, each nozzle 36 face a vaporization surface 202.

Each nozzle 36 can be offset from the vaporization surface 202 or alternatively, the nozzle 36 and the vaporization surface 202 may align direction one above the other.

When a user draws on the mouthpiece 31 , air is brought into the aerosol flow paths 35 through the air inlets connected to the aerosol flow paths 35 so as to create a pressure change that draws the generated aerosol flow to the mouthpiece as it passes over the vaporization surface 202.

In a setup where each nozzle 36 is offset from a corresponding vaporization surface 202, incoming air through the air inlets can flow sideways along the vaporization surface 202 and then pulls up from the nozzle 36. Alternatively incoming air through the air inlets can flow directly into the aerosol flow path 35 over the vaporization surface 202. The nozzle 36 is jetting either perpendicular to, or in parallel with the airflow of the mouthpiece.

The filter 22 is not shown on figure 3b but it shall be understood that the filter 22 is positioned such as to remove particles from the aerosol forming material 34 passing from the reservoirs 33 towards the vapor generation unit 20.

The filter 22 can be dimensioned depending on the size of the nozzles 36.

In an embodiment where the filter 22 is the last (or the only) part where the aerosol forming material 34 is filtered before exiting through the nozzles 36, the filter 22 is dimensioned to remove particles that are bigger than the nozzles 36. In other words, the filter 22 is sized to eliminate particles that are 100% of the nozzle diameter or larger.

In a preferred embodiment, the filter 22 is sized to remove particles that are around 50% diameter of the nozzle 36. For example, for a 3 pm nozzle diameter, the filter 22 is preferably a 1 .5 pm filter.

Furthermore, the filter 22 also needs to have a large enough flow area to minimize pressure drop. The calculations for pressure drop are performed at the end of life, i.e. when the total volume of aerosol forming material for the device has pass through the filter.

In the case of a very small filter 22, a pre-filter can be added that can filter particles of higher dimensions. For example, for a 1 pm or 2 pm filter, a pre-filter can be added that can filter particles in a 6 to 10 pm range. This will extend the life of the small filter while allowing for an overall smaller filter to be used.

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 a compact and inexpensive aerosol- generating device comprising a vapor generation unit benefiting therefore from the advantages provided by the MEMS technology while enabling the consumer to inhale a warm aerosol.

References used for the figures

Claims

CLAIMS An aerosol-generating device comprising a vapor generation unit (20), at least one reservoir (33) configured to store an aerosol forming material (34), and a filter (22) disposed so as to remove particles from said aerosol forming material (34) passing from said at least one reservoir (33) to the vapor generation unit (20), the vapor generation unit (20) comprising a micro electro-mechanical system (MEMS), the aerosol-generating device (1) being characterized in that the filter (22) is configured to heat the aerosol forming material (34) passing through it. The aerosol-generating device according to claim 1 wherein the micro electro-mechanical system of the vapor generation unit (20) comprises at least one MEMS die (200). The aerosol-generating device according to any one of claims 1 or 2 wherein the filter (22) is located adjacent to the vapor generation unit (20). The aerosol generation device according to any of claims 1 to 3, wherein the filter (22) is located below the vapor generation unit (20) in a longitudinal direction of the aerosol-generating device when the aerosol-generating device is in a use position. The aerosol generation device according to any one of claims 1 to 4, wherein the filter (22) is in contact with or almost in contact with the vapor generation unit (20). 6. The aerosol-generating device according to any one of claims 1 to 5, wherein the filter (22) comprises a mesh, preferably made of stainless- steel material.

7. The aerosol-generating device according to claim 6, wherein said filter (22) comprises at least one wire configured to heat all or part of the rest of the filter (22) by conduction when power is applied to the at least one wire.

8. The aerosol-generating device according to claim 7, wherein said at least one wire of the filter (22) extends through the mesh.

9. The aerosol-generating device according to any one of claims 7 or 8, wherein said at least one wire is embedded in the mesh.

10. The aerosol-generating device according to any one of claims 7 to 9, wherein said at least one wire is in contact with at least 30% of a lateral surface of the mesh, preferably at least 50%, and more preferably at least 60% of a lateral surface of the mesh.

11 . The aerosol-generating device according to any one of claims 7 to 10, wherein said at least one wire is a resistance wire adapted to convert electrical energy into heat when power is applied to it.

12. The aerosol-generating device according to any one of claims 7 to 10, wherein said at least one wire is heated by an external heating source, such as a resistive heater. 19

13. The aerosol-generating device according to any one of claims 7 to 12, wherein it comprises an induction coil configured to inductively heat said at least one wire. 14. The aerosol-generating device according to any one of claims 6 to 13, wherein the mesh has a porosity lower than 50% and preferably equal to 34%.

15. The aerosol-generating device according to any one of claims 1 to 14, wherein it comprises a battery configured to directly heat the filter.

16. The aerosol-generating device according to any one of claims 1 to 15, wherein the filter (22) is heated so as to bring the aerosol forming material to a temperature ranging between 50°C to 100°C.