Aerosol Generating Device

A system includes an aerosol generating device and a portion of aerosol generating substrate, the device including first and second housing elements configured to move between open and closed positions, wherein, in the closed position, the housing elements together define an aerosol generation chamber configured to enclose the portion, and further define an air flow channel including an inlet, an outlet and the chamber, the first housing element including a recess for receiving the portion, wherein the recess includes a flat bottom surface, and the second housing element includes a compression surface for compressing the portion towards the bottom surface, the compression and bottom surfaces being opposing surfaces of the chamber, wherein the portion is cuboid and a thickness of the portion before use in the device is greater than a distance between the compression and bottom surfaces when the first and second housing elements are in the closed position.

TECHNICAL FIELD

The present disclosure relates to an aerosol generation device in which an aerosol generating substrate is heated to form an aerosol. The disclosure is particularly applicable to a portable aerosol generation device, which may be self-contained and low temperature. Such devices may heat, rather than burn, tobacco or other suitable aerosol substrate materials by conduction, convection, and/or radiation, to generate an aerosol for inhalation.

BACKGROUND

The popularity and use of reduced-risk or modified-risk devices (also known as vaporisers) has grown rapidly in the past few years as an aid to assist habitual smokers wishing to quit smoking traditional tobacco products such as cigarettes, cigars, cigarillos, and rolling tobacco. Various devices and systems are available that heat or warm aerosolisable substances as opposed to burning tobacco in conventional tobacco products.

A commonly available reduced-risk or modified-risk device is the heated substrate aerosol generation device or heat-not-burn device. Devices of this type generate an aerosol or vapour by heating an aerosol substrate that typically comprises moist leaf tobacco or other suitable aerosolisable material to a temperature typically in the range 150° C. to 350° C. Heating an aerosol substrate, but not combusting or burning it, releases an aerosol that comprises the components sought by the user but not the toxic and carcinogenic by-products of combustion and burning. Furthermore, the aerosol produced by heating the tobacco or other aerosolisable material does not typically comprise the burnt or bitter taste resulting from combustion and burning that can be unpleasant for the user and so the substrate does not therefore require the sugars and other additives that are typically added to such materials to make the smoke and/or vapour more palatable for the user.

In such devices, a user must wait for an initial activation time while the aerosolisable material is heated to generate the aerosol, before it is possible to inhale a puff of aerosol. In order to improve user convenience it is desirable to decrease the initial activation time.

Additionally, it is desirable to increase the aerosol yield from aerosolisable material.

SUMMARY

According to a first aspect, the present disclosure provides an aerosol generating device comprising first and second housing elements configured to move between an open position and a closed position, wherein, in the closed position, the first and second housing elements together define an aerosol generation chamber configured to enclose a portion of aerosol generating substrate, and further define an air flow channel comprising an inlet, an outlet and the aerosol generation chamber, the first housing element comprising a recess for receiving the portion of aerosol generating substrate, wherein the recess comprises a flat bottom surface, and the second housing element comprising a compression surface for compressing the portion of aerosol generating substrate towards the bottom surface of the recess, the compression surface and bottom surface being opposing surfaces of the aerosol generation chamber.

By compressing the aerosol generating substrate towards the bottom surface of the recess, the thermal conductivity of the substrate can be improved, thereby decreasing the initial activation time. Furthermore, compressing the aerosol generating substrate can improve aerosol yield for a given quantity of substrate.

Optionally, the first and second housing members are connected by a hinge.

By connecting the housing members by a hinge, the housing members can be easily separated to access the aerosol generation chamber and insert and remove the aerosol generating substrate before and after aerosol generation. Furthermore, a hinge guides the housing members to compress the portion of aerosol generating substrate between the compression surface and the bottom surface of the recess.

Optionally, the device comprises a fastener for holding the first and second housing elements in the closed position.

By providing a fastener, it is not necessary for the user to apply a compression force throughout aerosol generation, making the device easier to use.

Optionally, the device comprises a gasket configured to, in the closed position, seal the air flow channel.

By sealing the air flow channel, air flows more efficiently from the outlet to the inlet through the aerosol generation chamber, and aerosol can be inhaled from the device more easily.

Optionally, the device comprises a heating element arranged to supply heat to the aerosol generation chamber through the bottom surface or the compression surface.

A heating element provides a convenient way of heating the aerosol generating substrate in the aerosol generation chamber. In alternatives, the substrate can be heated in other ways, for example, using a disposable heat source provided in the portion of aerosol generating substrate.

Optionally, the first housing element and/or the second housing element comprises an insulating member at least partly enclosing the aerosol generation chamber.

The insulating member improves efficiency of heating the aerosol generating substrate in the aerosol generation chamber.

Optionally, the second housing element additionally comprises an air flow channel configured to connect to the aerosol generation chamber in the closed position, and to provide the inlet and outlet.

Optionally, the air flow channel comprises a groove in a surface of the second housing element. A surface groove may be easily cleaned.

Optionally, the air flow channel comprises a groove in the compression surface. This increases air flow adjacent to where the compression surface compresses the substrate and improves aerosol extraction from the substrate.

Optionally, the air flow channel comprises a plurality of grooves in the compression surface connected between the inlet and the outlet.

Optionally, the inlet comprises a plurality of distinct inlets connected to the plurality of grooves.

Optionally, the plurality of grooves are arranged in parallel between the inlet and the outlet.

Optionally, a plurality of sections of the compression surface are separated by the one or more grooves of the air flow channel, and each of the plurality of sections of the compression surface is configured to compress the portion of aerosol generating substrate towards the bottom surface of the recess. This distributes air flow and compression across the substrate.

Optionally, the device comprises an electrical power source, wherein the aerosol generating device is a portable handheld device.

According to a second aspect, the present disclosure provides a system comprising an aerosol generating device according to any preceding claim and a portion of aerosol generating substrate, wherein a thickness of the portion before use in the aerosol generating device is greater than a distance between the compression surface and the bottom surface of the recess when the first and second housing elements are in the closed position.

According to a third aspect, the present disclosure provides a kit comprising an aerosol generating device according to any preceding claim and a portion of aerosol generating substrate, wherein a thickness of the portion before use in the aerosol generating device is greater than a distance between the compression surface and the bottom surface of the recess when the first and second housing elements are in the closed position.

DETAILED DESCRIPTION

FIGS.1A,1B and1Care schematic cross-sections of an aerosol generating device1, with lines x, y and z showing the relative planes of the cross-sections.

The aerosol generating device1comprises a first housing element11and a second housing element12. When the aerosol generating device1is in a closed position as shown inFIGS.1B and1C, the first housing element11and the second housing element12together define an aerosol generation chamber13in which a portion2of aerosol generating substrate aerosol is enclosed, and aerosol is generated from the portion2of aerosol generating substrate.

The first housing element11comprises a recess131for receiving the portion2of aerosol generating substrate, and the second housing element12comprises a compression surface132arranged to oppose a flat bottom surface of the recess131. When the aerosol generating device1is in the closed position as shown inFIGS.1B and1C, the compression surface132is arranged to oppose the bottom surface of the recess131, and the portion2is compressed by the compression surface132towards the bottom surface of the recess131. In this embodiment, the compression surface132is simply an extension of a surrounding flat surface of the second housing element12, and is the part of the flat surface which is arranged to oppose the recess131in the closed position.

In some embodiments, compression alone may be sufficient to cause release of the aerosol from the substrate. However, in many embodiments, a heating element14is arranged to supply heat to the aerosol generation chamber13in order to heat the aerosol generating substrate and generate the aerosol. In such embodiments, the application of pressure increases the yield of aerosol from the aerosol generating substrate compared to heating alone. In the embodiment ofFIGS.1A to1C, the heating element is arranged to supply heat through the bottom surface of the recess131. The heating element14may, for example, comprise a resistive track that is powered by electricity.

In further alternative embodiments, heating may be supplied without the use of a heating element14in the device1. For example, the portion2of aerosol generating substrate may also comprise a pressure-activated heat generating element such as a capsule of ingredients for an exothermic reaction.

The first housing element11may be formed from a thermally conductive material, such as a metal (e.g. aluminium), in order to allow heat transfer from the heating element14to the aerosol generating chamber13. However, the spacing between the heating element14and the aerosol generating chamber13is preferably minimized, and the first and second housing elements11,12preferably comprise a heat-resistant material such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polyamide (PA) in order to prevent thermal deformation or melting. The heat-resistant material may be a super engineering plastic such as polyimide (PI), polyphenylenesulfide (PPS) or polyether ether ketone (PEEK).

The device1also comprises an air flow channel15through the aerosol generation chamber13, which is provided in order to extract the generated aerosol from the aerosol generation chamber13. In the embodiment ofFIGS.1A to1C, the air flow channel15comprises an inlet151connected between the exterior of the device1and one end of the aerosol generation chamber13, and an outlet152connected between the exterior of the device1and another end of the aerosol generation chamber13. The exterior of the device1around the outlet152is configured as a mouthpiece so that a user can inhale air and aerosol through the device1. Alternatively, air may be artificially pumped through the air flow channel15, for example using a fan.

In the embodiment shown inFIGS.1A to1C, the first and second housing members11and12are connected by one or more fasteners16, which are hinges in this case, along a pivot line that is approximately aligned with a length direction between the inlet151and the outlet152. By rotating on the hinges16, the first and second housing elements11,12move between an open position (shown inFIG.1A) and a closed position (shown inFIGS.1B and1C). In the open position, the recess131is exposed, and the portion2of aerosol generating substrate can be added or removed, and the device can be cleaned. In the closed position, the aerosol generation chamber is completed and the aerosol can be generated. In other embodiments, the first and second housing members11and12may be fully separated in the open position, and may be connected together in the closed position by, for example, one or more releasable fasteners such as magnets or snap-fit connectors.

FIGS.2A and2Bare schematic perspective illustrations of alternative portions of aerosol generating substrate.

InFIG.2A, the portion21is a simple cuboid having length L, width W and depth D. In a typical example, the substrate is typically 18×12×1.2 mm, with each of L, W and D being selected within a range of +/−40%, for example.

The substrate may for example comprise nicotine or tobacco and an aerosol former. Tobacco may take the form of various materials such as shredded tobacco, granulated tobacco, tobacco leaf and/or reconstituted tobacco. Suitable aerosol formers include: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, acids such as lactic acid, glycerol derivatives, esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerin or vegetable glycerin. In some embodiments, the aerosol generating agent may be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. The substrate may also comprise at least one of a gelling agent, a binding agent, a stabilizing agent, and a humectant.

The substrate is porous such that air can flow through the substrate and collect aerosol as it does so. The substrate may for example be a foam, or packed strands or fibres. The substrate may be formed through an extrusion and/or rolling process into a stable shape.

The portion of aerosol generating substrate is designed to be thicker (larger depth D) than the distance between the compression surface132and the bottom surface of the recess131when the device1is in the closed position. This means that the portion2must be compressed in order to reach the closed position with a portion2of aerosol generating substrate in the device1.

As shown inFIG.2B, in addition to being porous, the portion22of aerosol generating substrate may be shaped to provide one or more air flow channels. These can be aligned with the air flow channel15of the aerosol generating device1in order to increase air flow through the aerosol generation chamber13.

In each ofFIGS.2A and2B, the portion2has a bare external surface in which the aerosol generating substrate is exposed. Alternatively, the portion2may comprise an air permeable wrapper covering at least part of a surface of the aerosol generating substrate. The wrapper may, for example, comprise paper and/or non-woven fabric.

FIGS.3A and3Bare schematic illustrations of compression of the aerosol generating substrate.

As shown inFIG.3A, while the recess131may be a cuboid recess of length L, width W and configured to receive a cuboid portion21with the same length L, width W, a depth d of the recess131is however smaller than a natural depth D of the portion of aerosol generating substrate2. As a result, when the device is in the closed position shown inFIG.3B, it may be estimated that the aerosol generating substrate is compressed by a factor of d divided by D.

The inventors have found that compression of a substrate may result in improved heat transfer to the entire substrate, due to reduced amounts of air gaps therein, thus contributing to a shorter heat-up time to a suitable operating temperature, and a uniform amount of aerosol generation and an associated flavor throughout when the aerosol is inhaled.

Too weak compression i.e. too large ratio may not cause the anticipated results, and too strong compression i.e. too small ratio may cause an adverse effect due to reduced air-permeability through the substrate, such as an increased resistance to draw through a mouthpiece, and a reduced amount of aerosol delivery to a user.

FIGS.4A to4Eare schematic cross-sections of different aerosol generating devices having alternative or optional features.

FIG.4Aillustrates an alternative aerosol generating device1in the open position. In this example, the compression surface132(1321,1322) is not simply a part of a flat surface of the second housing element12, but is raised or recessed relative to the surrounding surface.

FIG.4Billustrates the recessed case, in which the consumable2partly engages with the recessed compression surface1321. The thickness of the first and second housing elements11,12is partly dictated by a required strength to reduce the chance of the elements breaking in use. Using a part of the second housing element12as space for the portion2of aerosol generating substrate uses the minimum volume of the device1(as dictated by strength requirements) more efficiently and increases the amount of aerosol which can be generated from the device1.

Additionally, and independently from the specific compression surface1321, the example ofFIG.4Billustrates how the heating element14may alternatively be located in the second housing element12to supply heat to the aerosol generation chamber through the compression surface132.

FIG.4Cillustrates the case where the compression surface1322is raised relative to the surrounding surface of the second housing element12. A raised compression surface1322allows a minimum depth of the recess131to be provided even for small portions2of the aerosol generating substrate.

Additionally, and independently from the specific compression surface1322, the example ofFIG.4Cillustrates how multiple heating elements141,142may be arranged generally in the first and/or second housing elements11,12.

Furthermore, the example ofFIG.4Cillustrates an insulating member17in the first housing element11. The insulating member17comprises a material with lower thermal conductivity than the first housing element11, such as an aerogel, inorganic fibers, or a foamed resin. Alternatively, the insulating member17may comprise a vacuum insulator. The insulating member17is arranged to partially enclose the aerosol generating chamber13and the heating element14in order to improve heating efficiency. For example, the insulating member17may be arranged to extend along one or more sides of a heating element14that are not facing the aerosol generating chamber13or one or more sides of the aerosol generating chamber13. An insulating member17is similarly provided in the second housing element12to further insulate the aerosol generating chamber13. In one example, the housing elements11,12may be formed from a material which is not specialised for insulation, such as a metal, for example aluminium. At the same time, the insulating member17is formed from a substantially more insulating material such as polyimide (PI), polyphenylenesulfide (PPS) or polyetheretherketone (PEEK).

FIGS.4D and4Eillustrate an alternative configuration of the compression surface in which a plurality of protrusions1323(or alternatively recesses) are arranged to oppose the recess131in the closed position. By providing multiple protrusions1323spaced apart from each other, the pressure applied to the portion2of aerosol generating substrate varies through the substrate, and air flow is higher in between protrusions. As a result, areas of higher aerosol generation (where pressure is applied by a protrusion1323) are adjacent to areas of higher air flow, increasing the amount of aerosol which is extracted by drawing air through the aerosol generating substrate.

FIGS.5A to5Dare schematic cross-sections of further different aerosol generating devices having alternative or optional features.

InFIGS.5A and5B, the inlet151and outlet152are rearranged as surface groove features of an air flow channel in the second housing element12extending through the compression surface1324.

On the other hand, inFIGS.5C and5D, the air flow channel15is embedded within the second housing element12and, in the closed position, connects to the aerosol generation chamber13via one or more openings153in the compression surface1325.

The alternative configurations ofFIG.5have the advantage that air flow through the air flow channel15is not directly impeded by the portion2of aerosol generating substrate, and the aerosol is added to the air flow by evaporation, meaning that the pressure difference for drawing air through the device1is fixed and the strength of aerosol drawn from the device can be controlled according to the rate of drawing air through the device.

Additionally, the configuration ofFIGS.5A and5Bhas the advantage that it is easier to clean a groove than an embedded channel.

As an additional variation, the air flow channel15may be provided partly in features of the first housing element11and partly in features of the second housing element12. For example, each housing element may have a surface groove which, in the closed position, provides a part of the air flow channel15.

FIGS.6A to6Dare schematic cross-sections of different aerosol generating devices having further alternative or optional features. In particular,FIGS.6A to6Dshow variations on the housing elements11,12and the fastener16ofFIG.1.

InFIG.6A, the first housing element11comprises a main portion111and a mouthpiece portion112. The main portion111operates similarly to the example ofFIG.1, and opposes the second housing element12in the closed position in order to form the aerosol generating chamber13. However, in this example, the second housing element12does not extend as far as the outlet152meaning that the mouthpiece portion112is fixed.

Similarly, inFIG.6B, the first housing element11comprises a main portion111and an inlet portion113, where the second housing element12opposes the main portion111to form the aerosol generating chamber13.

By providing a fixed outlet portion112or inlet portion113, the air flow through the device1can be more predictably defined, even if the first housing element11and second housing element12are not perfectly positioned in the closed position, making the device1easier to operate.

FIGS.6C and6Dillustrate an alternative aerosol generating device1in which the fasteners16are aligned perpendicular to the length direction between the inlet151and the outlet152. This configuration may be easier for a user to operate and move between open and closed positions with one hand, leaving the other hand free for handling the portion2of aerosol generating substrate.

FIG.7is a perspective view of a first specific example of an aerosol generating device in the open position.

In this example, each of the first and second housing elements11,12comprises an inner portion111,121and an outer portion114,122. The outer portions114,122provide an outer casing which is configured to be handheld. For example, the outer portions114,122may comprise a rigid metal casing supporting weaker inner portions111,121. Additionally or alternatively, the outer portions114,122may have lower thermal conductivity than the inner portions, in order to protect a user's hand, for example by providing an elastomer grip on an outer surface of the device.

Additionally, in the first specific example, the air flow channel15comprises a plurality of distinct inlets1511(two in this case) in one end of the outer portion122of the second housing element12, to provide the inlet151. Air then flows into two channels extending in parallel, the channels being formed as grooves on a surface of the inner portion121of the second housing element12connected between the inlet and the outlet. The grooves are surrounded by and separated by portions of the compression surface132, with a similar effect to the example ofFIG.4Dof providing regions of improved aerosol generation adjacent to regions of improved airflow in the portion2of aerosol generating substrate.

The grooves provide a channel of varying width between the inlets and the outlet, with small inlets and a comparatively large outlet. When air is drawn through the device1in the closed position, this configuration creates a pressure gradient in the air flow channel15and reduces the air pressure adjacent to the portion2of aerosol generating substrate, further increasing aerosol generation.

Additionally, in the first specific example, the heating element14(not shown inFIG.7but configured similarly toFIGS.1B and1Cadjacent to the flat bottom surface of the recess131) is driven by an external power source connected by electrical wire18. The device1can be manufactured for use with an external power source, by cutting or moulding space for the electrical wire18in the inner portion111of the first housing element11, and then providing a glue fill section181to separate the air flow channel15from the electrical wire18. Alternatively section181could be an additional solid component that is fitted in place, such as a snap-fit or press-fit component. In some embodiments, the electrical wire18connecting to an external power source can be replaced with an internal power source. With an internal power source, the aerosol generating device can be provided as a portable handheld device.

Furthermore, in the first specific example, the device1comprises several closing means191,192and193for improving the closure of the device1in the closed position and thereby making the device1easier to operate with good aerosol generation.

Firstly, the first and second housing elements11,12are held in place in the closed position using one or more releasable fasteners (e.g. pairs of opposing magnets191) opposed to the hinge16. Providing releasable fasteners means that the device1need not be held in the closed position by hand throughout aerosol generation, making the device easier to use.

Secondly, tab surfaces192are provided which can be manually operated by a user's hand to open and close the device1between the open and closed positions. Providing the tab surfaces192means that the strength of the releasable fasteners can be increased without making it difficult for a user to move the device1from the closed position to the open position.

Thirdly, a gasket193is provided which, in the closed position, improves sealing of the air flow channel15between the inlet(s) and the outlet. The gasket may, for example, be formed from an elastomer such as rubber.

The first specific example of device1may suitably be used with a portion2of aerosol generating substrate that has a thickness D that gives a compression ratio d/D of between 0.6 and 0.9, more preferably between 0.7 and 0.8, wherein d is the depth of the recess131.

FIG.8is a perspective view of the first specific example in the closed position (where the electrical wire18is not shown for simplicity).

As shown inFIG.8, the device1has a mouthpiece portion112similar toFIG.6Asurrounding the outlet152. As further shown inFIG.8, an exterior surface of the second housing portion12is configured to align with an exterior surface of the mouthpiece portion112in the closed position, to provide a smooth exterior shape.FIG.8also illustrates that the tab surfaces192in the first specific example are configured to align in the closed position such that they can be easily pinched by hand in order to open the device1.

Aerosol generating substrate includes tobacco, for example in dried or cured form, in some cases with additional ingredients for flavouring or producing a smoother or otherwise more pleasurable experience. In some examples, the substrate such as tobacco may be treated with a vaporising agent. The vaporising agent may improve the generation of vapour from the substrate. The vaporising agent may include, for example, a polyol such as glycerol, or a glycol such as propylene glycol. In some cases, the substrate may contain no tobacco, or even no nicotine, but instead may contain naturally or artificially derived ingredients for flavouring, volatilisation, improving smoothness, and/or providing other pleasurable effects. The substrate may be provided as a solid or paste type material in shredded, pelletised, powdered, granulated, strip or sheet form, optionally a combination of these. Additionally, the aerosol substrate may comprise a liquid or gel.

The aerosol generating device1could in some embodiments be referred to as a “heated tobacco device”, a “heat-not-burn tobacco device”, a “device for vaporising tobacco products”, and the like, with this being interpreted as a device suitable for achieving these effects. The features disclosed herein are equally applicable to devices which are designed to vaporise any aerosol substrate.

The aerosol generating device1may be arranged to receive the portion2of aerosol generating substrate in a pre-packaged substrate carrier. Filters, vapour collection regions, cooling regions, and other structure may also be included in some designs or the aerosol generating device1.

As used herein, the term “fluid” shall be construed as generically describing non-solid materials of the type that are capable of flowing, including, but not limited to, liquids, pastes, gels, powders and the like. “Fluidized materials” shall be construed accordingly as materials which are inherently, or have been modified to behave as, fluids. Fluidization may include, but is not limited to, powdering, dissolving in a solvent, gelling, thickening, thinning and the like.

As used herein, the term “volatile” means a substance capable of readily changing from the solid or liquid state to the gaseous state. As a non-limiting example, a volatile substance may be one which has a boiling or sublimation temperature close to room temperature at ambient pressure. Accordingly “volatilize” or “volatilise” shall be construed as meaning to render (a material) volatile and/or to cause to evaporate or disperse in vapour.

As used herein, the term “vapour” (or “vapor”) means: (i) the form into which liquids are naturally converted by the action of a sufficient degree of heat; or (ii) particles of liquid/moisture that are suspended in the atmosphere and visible as clouds of steam/smoke; or (iii) a fluid that fills a space like a gas but, being below its critical temperature, can be liquefied by pressure alone.

Consistently with this definition the term “vaporise” (or “vaporize”) means: (i) to change, or cause the change into vapour; and (ii) where the particles change physical state (i.e. from liquid or solid into the gaseous state).

As used herein, the term “atomise” (or “atomize”) shall mean: (i) to turn (a substance, especially a liquid) into very small particles or droplets; and (ii) where the particles remain in the same physical state (liquid or solid) as they were prior to atomization.

As used herein, the term “aerosol” shall mean a system of particles dispersed in the air or in a gas, such as mist, fog, or smoke. Accordingly the term “aerosolise” (or “aerosolize”) means to make into an aerosol and/or to disperse as an aerosol. Note that the meaning of aerosol/aerosolise is consistent with each of volatilise, atomise and vaporise as defined above. For the avoidance of doubt, aerosol is used to consistently describe mists or droplets comprising atomised, volatilised or vaporised particles. Aerosol also includes mists or droplets comprising any combination of atomised, volatilised or vaporised particles.