Aerosol generation device and method of assembling such a device

Abstract

An aerosol generation device (2) comprising an absorber (14) positioned adjacent to a reservoir (9) is disclosed. The reservoir (9) comprises an aerosol forming substrate (28) which is a suspension of a solid fraction and a liquid fraction. The absorber (14) is configured to separate the liquid fraction from the solid fraction by absorbing the liquid fraction. A heater (6) is provided in thermal contact with the absorber, thereby heating the liquid fraction of the aerosol forming substrate (28). A controller is also provided that is configured to control a supply of power to the heater (6). A method of assembling a component for use in the aerosol generation device (2) is also disclosed.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to an aerosol generation device. The disclosure is particularly applicable to a portable aerosol generation device, which may be self-contained and low temperature. Specifically, the present disclosure relates to aerosol generation devices that can vaporise a liquid aerosol forming substrate.BACKGROUND

[0002] Consumer interest in reduced-risk or modified-risk aerosol generation devices (also known as vaporisers or electronic cigarettes) has increased significantly in recent years. Vaporisers offer an aid to habitual smokers wishing to quit using traditional tobacco products such as: cigarettes, cigars, cigarillos, and rolling tobacco. Traditional tobacco products burn the tobacco to produce an aerosol that the user inhales. Conversely, vaporisers generate an aerosol, or vapour, by heating an aerosol forming substrate. The present disclosure is directed to a type of aerosol generation device that vaporises a liquid aerosol forming substrate to generate an aerosol.

[0003] Traditionally, aerosol generation devices, or electronic cigarettes, produce the desired aerosol, but the aerosol forming substrate may also comprise non-volatile compounds that are not vaporised and are subsequently deposited on a heating element of the device. This effect, known in the art as fouling, can insulate the heating element, thereby reducing the efficiency of the heating element, and requiring a greater supply of power to achieve the same heating effect. By increasing power demand, the device may deplete its power supply more quickly than expected, and may require more frequent charging operations. Alternatively, more power may not be provided to the heating element, to compensate for the insulating effect of fouling, in which case the device may become progressively less capable of producing the desired volume of aerosol. The non-volatile compounds, or foulants, may themselves be vaporised, which may lead to the production of undesirable chemicals. Ultimately, this provides an unsatisfactory experience for the user.

[0004] The present invention aims to address one or more of these issues.SUMMARY OF INVENTION

[0005] In an aspect of the invention there is provided an aerosol generation device, comprising: a reservoir configured to store an aerosol forming substrate having solid and liquid fractions; an absorber positioned adjacent the reservoir, configured to separate the liquid fraction of the aerosol forming substrate from the solid fraction by absorbing the liquid fraction from the reservoir; a heater arranged to be in thermal contact with the separated liquid fraction of the aerosol forming substrate; and a controller configured to control a supply of power to the heater.

[0006] In this way, only the liquid fraction of the aerosol forming substrate may be in contact with the heater. This may lead to a reduction in, or prevent entirely, the effects of fouling which are caused by the solid fraction being in contact with the heater. This in-turn may improve the efficiency of the heater by preventing the solid fraction from insulating the heater. This may also prevent the formation of undesirable chemicals caused by vaporizing the solid fraction. By providing a controller to control a supply of power to the heater, the temperature of the heater may be controlled. This may also reduce, or prevent, fouling.

[0007] Preferably, the absorber is positioned below the reservoir, in use, so that a gravitational force is applied to the aerosol forming substrate in the reservoir, towards the absorber. This may increase a rate at which the solid and liquid fractions separate from one another. In some designs the device may be inverted from its normal operating position to place the absorber below the reservoir and allow gravity to act on the aerosol forming substrate in the reservoir.

[0008] Preferably, the aerosol generation device further comprises a compressor configured to apply a pressure to the aerosol forming substrate in the reservoir thereby to promote the absorption of liquid in the absorber.

[0009] Preferably, the compressor is positioned adjacent the absorber and is configured to compress the absorber towards the reservoir to promote the absorption of liquid in the absorber. After compressing the absorber towards the reservoir, the compressor may be configured to move away from the reservoir, thereby allowing the absorber to decompress. As this occurs, a negative pressure may be created in the absorber to further promote absorption of liquid from the reservoir.

[0010] Preferably, the absorber comprises a compressible material that can absorb liquid and a porous, non-compressible material that is positioned at the interface with the reservoir. The absorber may comprise polyamide (PA) polypropylene (PP) polyethylene terephthalate (PET) polyethylene (PE) or a combination thereof. The density of the absorber may therefore be between 0.02 and 0.2 g / cm3. The volume of the absorber may be between 20% to 200% of the volume occupied by the aerosol forming substrate in the reservoir. The non-compressible material may comprise: metal, resin, hard silicon, polymers, or a combination thereof. The non-compressible material may be shaped in a mesh.

[0011] Preferably, the heater comprises a plurality of electrically resistive tracks formed in a mesh. A mesh heater may provide a more uniform heat distribution compared to other heaters, which reduces, or prevents, fouling by reducing local hot spots.

[0012] In another aspect of the invention, there is provided a method of assembling a component for use in an aerosol generating device, comprising steps of: filling a reservoir with an aerosol forming substrate having solid and liquid fractions; positioning an absorber adjacent to the reservoir; separating the liquid fraction of the aerosol forming substrate from the solid fraction by absorbing the liquid fraction in the absorber from the reservoir; and positioning a heater in thermal contact with the separated liquid fraction.

[0013] Preferably, the method includes at least one of: compressing the absorber towards the reservoir, applying a differential gas pressure to promote absorption of the liquid fraction by an absorber; positioning the absorber below the reservoir to promote absorption of the liquid fraction by the absorber by gravity; and applying a rotation to promote absorption of the liquid fraction by the absorber by the centrifugal effect. The method may involve inverting the device from its normal operating orientation in order to place the absorber below the reservoir.

[0014] In another aspect of the invention, there is provided an aerosol generation device, comprising: a reservoir configured to store an aerosol forming substrate having solid and liquid fractions; a mechanical piston positioned adjacent the reservoir, configured to separate the liquid fraction of the aerosol forming substrate from the solid fraction; a heater arranged to be in thermal contact with the separated liquid fraction of the aerosol forming substrate; and a controller configured to control a supply of power to the heater, wherein the mechanical piston is movable relative to the aerosol forming substrate in the reservoir, and wherein the piston comprises a porous filter for separating the liquid fraction from the solid fraction.

[0015] In this way, the piston may be pressed in a direction towards the reservoir such that the porous filter compresses the aerosol forming substrate held therein, thereby separating the solid and the liquid fractions. The pores of the porous filter may be provided with a radius that is large enough to prevent the pressure of forcing the liquid fraction through the filter from becoming too great, while simultaneously being provided with a radius that is small enough to prevent a substantial amount of the solid fraction from passing through the pores. To this effect, the radius of the pores may be between 100µm and 500µm. If the pores are not circular, then half of the width of the pores may be between 100µm and 500µm. The separator may comprise hard resins, plastics, metal, or a combination thereof.

[0016] Preferably, the mechanical piston comprises a cavity in which the separated liquid fraction can be retained.

[0017] Preferably the porous filter is provided on an end face of the mechanical piston, which is supported by longitudinal pillars. The longitudinal pillars may prevent movement of the end face in a longitudinal direction. Therefore, the end face may be reinforced when compressing the aerosol forming substrate.

[0018] Preferably, the aerosol generation device further comprises reinforcement struts that connect the longitudinal pillars together at respective positions that are longitudinally separated from the porous end face. The reinforcement structs may prevent motion of the longitudinal pillars in a lateral direction. The reinforcement structs may comprise through-holes to allow passage of the liquid fraction.

[0019] Preferably, the mechanical piston comprises at least one o-ring at a position that is longitudinally distal from the porous filter. The o-ring may create a seal between the reservoir and the piston. This may secure the piston in use.BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1A is a schematic view of an aerosol generation device comprising a cartridge, in an embodiment of the invention; Figure 1B is a cross-sectional view of the cartridge, showing its interior, positioned in a normal orientation of use with a mouthpiece end positioned towards the top, in an embodiment of the invention; Figure 2A shows a series of steps in a method of producing the cartridge, in an embodiment of the invention; Figure 2B demonstrates an alternative series of steps in a production process for the cartridge; Figure 3A depicts a portion of an aerosol generation device in an alternative arrangement; and Figure 3B shows an enlarged version of the separator shown in Figure 3A. DETAILED DESCRIPTION

[0021] Figure 1A is a schematic view of an aerosol generation device 2 comprising a cartridge 4. Figure 1B is a cross-sectional view of the cartridge 4, showing its interior, positioned in a normal orientation of use with a mouthpiece end 11 positioned towards the top. The cartridge 4 has a generally cylindrical shape with a hollow interior. A channel 20 is positioned in the hollow interior and the channel 20 extends from a bottom portion 13 of the cartridge 4 to the mouthpiece end 11, through the centre. The channel 20 comprises a flared opening 3 in the mouthpiece end 11. In use, a user inhales generated aerosol through the flared opening 3.

[0022] A reservoir 9 is provided within the cartridge 4. The reservoir 9 has an annular shape in a ring around the channel 20, and is configured to store an aerosol forming substrate. The reservoir 9 is provided towards the mouthpiece end 11 of the cartridge 4.

[0023] An absorber 14 is provided in contact with the base of the reservoir 9. The absorber 14 is annular in shape and comprises a compressible porous material that can absorb liquid from the reservoir 9. In practice, the absorber 14 and the reservoir 9 are provided within a single, internal, annular-shaped cavity. In an optional arrangement, the absorber may be structurally supported by inserts 18 on internal and external radial surfaces. In some examples, the inserts 18 comprise plastics. The inserts 18 provide structural rigidity that allow the absorber 14 to be more easily assembled around the channel 20 and to be more easily loaded into the cartridge 4. In some embodiments the absorber 14 may be a foam comprising: polyamide (PA), polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE), or a combination thereof. The density of the absorber 14 is therefore between 0.02 g / cm 3< and 0.2 g / cm 3< . In some examples, the volume of the absorber is between 20% to 200% of the volume occupied by the reservoir 9. In some examples of the invention, a non-compressible separator 16 may be provided between the absorber 14 and the base of the reservoir 9. The separator 16 is an annular disc comprising a metal, resin, hard silicon, or polymer mesh that is designed to allow liquid to pass through, but to prevent passage of solid material from the reservoir 9.

[0024] A heater 6 is provided towards the bottom portion 13 of the cartridge 4. The heater 6 is located inside a heating chamber, which is configured to receive aerosol forming substrate from the absorber 14. A wicking material 17 is provided in fluid communication with the absorber 14 in order to create a flow path that allows the aerosol forming substrate to flow towards the heater 6. The heater 6 has a cylindrical shape and is positioned around the bottom end of the channel 20. In some embodiments, the heater surface is formed from a plurality of electrically resistive tracks formed in a mesh. The heater 6 is in contact with the wicking material 17.

[0025] The aerosol forming substrate provided in the reservoir 9 comprises solid and liquid fractions. The solid fraction is initially suspended in the liquid fraction when the aerosol forming substrate is loaded in the reservoir 9. Once the cartridge 4 has been assembled, the absorber 14 is positioned above the heater 6. Liquid is drawn into the absorber 14 from the reservoir 9 by capillary action. Liquid from the absorber 14 flows into the wicking material 17 under the effect of gravity and by capillary action. The liquid can be vaporised by the heater 6 to produce an aerosol that can escape the cartridge 4 through the channel 20.

[0026] The shape of the cartridge 4 is not limited to being cylindrical. For example, the cartridge 4 may be planar. In one design, the absorber 14, separator 16 and inserts 18 (if provided) may be positioned to one side of a channel 20, rather than surrounding it.

[0027] The aerosol generation device 2 comprises a controller 8 configured to control a supply of power to the heater 6 to control the temperature of the heater 6. The power is supplied by a power supply 19 which, in the examples of Figure 1A and Figure 1B, is a battery. In some embodiments, the controller 8 implements pulse width modulation to control the temperature of the heater.

[0028] Figure 2A shows a series of steps in a method of producing the abovementioned cartridge 4. The method begins, at step 100, by loading the aerosol forming substrate 28, which is a paste comprising solid and liquid fractions, into the reservoir 9. At step 101 an absorber 14 is provided. At step 102, the absorber 14 is positioned between the inserts 18 and on top of the separator 16. At step 104 the absorber 14, inserts 18, and separator 16, are then installed above the aerosol forming substrate 28 in the reservoir 9, in the inverted configuration of the device shown in Figure 2A. At step 106, the heater 6, which is positioned within the wicking material 17, is installed in the device in contact with the top surface of the absorber 14 (in the inverted orientation depicted in Figure 2A). In operation, the liquid fraction of the aerosol forming substrate 28 is drawn into the absorber 14, through the separator 16, by capillary action. In this way, separation of the solid fraction and the liquid fraction of the aerosol forming substrate 28 is achieved. The rate of separation of these two fractions can be increased by inverting the cartridge 4 after step 106. That is, the cartridge 4 is orientated such that the bottom portion 13 is beneath the mouthpiece end 11 and, accordingly, gravity can act on the liquid fraction to encourage it to be drawn into the absorber 14 from the aerosol forming substrate 28.

[0029] Figure 2B demonstrates an alternative production process for the cartridge 4. At step 200 the aerosol forming substrate 28 is introduced to the reservoir 9. At step 202 the absorber 14 is installed on top of the aerosol forming substrate 28, such that the two are in contact. Optionally, a separator 16 may be provided at this step and positioned between the absorber 14 and the aerosol forming substrate 28. At step 204, a compressor 29 is positioned adjacent to the absorber 14 and compresses the absorber towards the reservoir 9. The compressor 29 is a piston that is formed, in some arrangements, from a rigid plastic. After compressing the absorber 14 towards the reservoir 9, the compressor 29 is withdrawn. At step 206 the absorber 14 decompresses and a negative pressure is created to draw the liquid fraction from the aerosol forming substrate 28 into the absorber 14.

[0030] In other examples (not shown) other mechanisms can be provided to encourage the separation of the liquid and solid fractions, and the absorption of liquid by the absorber 14. In one example, a vacuum pump may be provided at the upper end of the cartridge 4 as shown in the inverted configuration of Figure 2B in order to create a differential gas pressure and draw liquid into the absorber 14. In further examples, the cartridge 4 may be positioned within a centrifuge which applies a rotation thereby promoting, by the centrifugal effect, absorption of the liquid fraction by the absorber 14.

[0031] Following step 206, it can be seen that the solid fraction remains within the reservoir 9, while the liquid fraction is substantially drawn into the absorber 14. Figure 3A depicts a portion of an aerosol generation device in an alternative configuration. In Figure 3A, a cartridge 30 is provided comprising an open base portion 37. The cartridge also comprises a mouthpiece portion 31 and a central channel 33 positioned therein. The channel 33 extends through the cartridge 30 along its central axis. A reservoir with an annular shape is positioned around the channel 33 for holding an aerosol forming substrate 28 which initially comprises solid and liquid fractions.

[0032] In Figure 3A a unitary heater 32 is shown. The unitary heater 32 can be installed in the channel 33 in the cartridge 30 so that it can be positioned in fluid communication with the reservoir and the aerosol forming substrate 28.

[0033] A piston 40 is provided which is configured to be inserted into the cartridge 30 through the open base portion 37. The piston 40 may be made of hard resin, plastic, metal, or a combination thereof. Figure 3B shows an enlarged version of the piston 40. The piston 40 comprises an end face 42 having a porous filter 41. The porous filter 41 is an annular disc with a series of through-holes that can allow passage of the liquid fraction of the aerosol forming substrate 28, while preventing passage of the solid fraction. The piston 40 comprises a central cavity 43 configured fit around the channel 33 in the cartridge 30, upon the piston 40 being inserted into the cartridge 30 at the open base portion 37. The end face 42 of the piston 40 is supported by longitudinal pillars 44, which are provided with support struts 45 which are provided in a ring at a position that is longitudinally spaced from the end face 42. The longitudinal pillars 44 help to prevent movement of the end face 42 in a longitudinal direction. The support struts 45 are provided with through-holes 46 that allow passage of the liquid fraction of the aerosol forming substrate 28, and they can provide structural rigidity to the pillars 44 in a lateral direction. An o-ring 47 is provided on an outer surface 49 of the piston 40 at a position that is longitudinally distal from the porous filter 41.

[0034] In use, the piston 40 is inserted into the cartridge 30 through the open base end 37. The piston 40 can be slid into the cartridge 30 so that it moves relative to the aerosol forming substrate 28 in the reservoir 9. As it is inserted, the porous filter 41 makes contact with the aerosol forming substrate 28. The porous filter 41 begins to compress the aerosol forming substrate 28 thereby forcing the liquid fraction through the through-holes, while acting as a barrier to the solid fraction. The through-holes of the porous filter 41 are provided with a radius that is large enough to prevent the pressure of forcing the liquid fraction through the filter 41 from becoming too great, while simultaneously being provided with a radius that is small enough to prevent a substantial amount of the solid fraction from passing through. To this effect, the radius of the through-holes 41 has been selected to be between 100µm and 500µm.

[0035] Once the piston 40 is fully inserted into the cartridge 30, the o-ring 47 is positioned in contact with the interior of the rim of the base end 37. This forms a liquid-tight seal between the piston 40 and the cartridge 30. Two or more o-rings 47 may be provided.

[0036] In other examples of this arrangement (not shown), the piston 40 is provided with an absorber positioned adjacent to the end face 42. The absorber can be made from a porous material. The absorber may comprise: foam Nylon, Polytetrafluoroethylene, Polyvinylidene fluoride, Polyethersulfone, Cellulose Acetate, Regenerated Cellulose, Polypropylene, Glass Fiber, Track Etched Polycarbonate Filter, or combinations thereof. The absorber may be provided in the form of a disk, a soft net, or rigid net. The absorber is positioned on either surface of the end face 42. This can provide a further filtration effect to enhance the separation of solid and liquid fractions.

Claims

1. An aerosol generation device, comprising: a reservoir configured to store an aerosol forming substrate having solid and liquid fractions; an absorber positioned adjacent the reservoir, configured to separate the liquid fraction of the aerosol forming substrate from the solid fraction by absorbing the liquid fraction from the reservoir; a heater arranged to be in thermal contact with the separated liquid fraction of the aerosol forming substrate; and a controller configured to control a supply of power to the heater.

2. The aerosol generation device of claim 1, wherein the absorber is positioned below the reservoir, in use, so that a gravitational force is applied to the aerosol forming substrate in the reservoir, towards the absorber.

3. The aerosol generation device of claim 1 or claim 2, further comprising a compressor configured to apply a pressure to the aerosol forming substrate in the reservoir thereby to promote the absorption of liquid in the absorber.

4. The aerosol generation device of claim 3 wherein the compressor is positioned adjacent the absorber and is configured to compress the absorber towards the reservoir to promote the absorption of liquid in the absorber.

5. The aerosol generation device of claim 4, wherein the absorber comprises a compressible material that can absorb liquid and a porous, non-compressible material that is positioned at the interface with the reservoir.

6. The aerosol generation device of any of the preceding claims, wherein the heater comprises a plurality of electrically resistive tracks formed in a mesh.

7. A method of assembling a component for use in an aerosol generating device, comprising steps of: filling a reservoir with an aerosol forming substrate having solid and liquid fractions; positioning an absorber adjacent to the reservoir; separating the liquid fraction of the aerosol forming substrate from the solid fraction by absorbing the liquid fraction in the absorber from the reservoir; and positioning a heater in thermal contact with the separated liquid fraction.

8. The method of claim 7, wherein the method includes at least one of: compressing the absorber towards the reservoir; applying a differential gas pressure to promote absorption of the liquid fraction by an absorber; positioning the absorber below the reservoir to promote absorption of the liquid fraction by the absorber by gravity; and applying a rotation to promote absorption of the liquid fraction by the absorber by the centrifugal effect.

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