Patent Description:
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 generating device or heat-not-burn device. Devices of this type generate an aerosol or vapour by heating an aerosol generating substrate that typically comprises moist leaf tobacco or other suitable aerosolisable material to a temperature typically in the range <NUM> to <NUM>. Heating an aerosol generating 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 it is desirable to improve heating speed and efficiency. It is therefore desirable to provide alternative configurations for a heater which can improve one or more of heating speed and heating efficiency, or which can be controlled to improve heating speed or heating efficiency.

In a previous application <CIT> by the applicant, the above problems were addressed with a layered heating structure in which heat is conducted from a conductive track, through an electrical insulation layer, and then through a heat conduction layer (such as a layer of stainless steel) to supply heat at a heating surface on an opposite side of the heating layer. With this arrangement, the conductive track is protected away from the heating surface, and the heating surface can be easily cleaned. However, the heating speed and efficiency could still be further improved.

<CIT>, <CIT>, <CIT> and <CIT> all disclose heaters for aerosol generating devices.

According to a first aspect, the present disclosure provides a heater for heating a consumable comprising a solid aerosol generating substrate, the heater comprising: a base; and a heating element attached to a support surface of the base, wherein the heating element comprises a moulding surface configured to deform and heat the aerosol generating substrate.

With this configuration, the heating element reaches closer to a centre of the aerosol generating substrate and can thus more efficiently deliver heat throughout the aerosol generating substrate.

Optionally, the heating element comprises a thick conductive track extending along and protruding from the support surface. With this configuration, the site of heat generation is placed as close as possible to the aerosol generating substrate, to further improve heating efficiency.

Optionally, the heater comprises a substrate protruding from the base to form a moulding shape or blade shape, and a conductive track on the substrate. With this configuration, the moulding surface can be provided without increasing a thickness of the heating element.

Optionally, the substrate is an extension of the base.

Optionally, the conductive track has a serpentine configuration. This configuration increases the resistance of the conductive track in a given area of the support surface.

Optionally, the heating element protrudes from the support surface by a protrusion distance of at least <NUM>.

Optionally, the base comprises a porous ceramic material, and at least part of the support surface is exposed to receive a vapour or aerosol generated from the aerosol generating substrate. This configuration provides additional volume for vapour/aerosol formation adjacent to the aerosol generating substrate.

According to a second aspect, the present disclosure provides an aerosol generation device comprising a substrate storage chamber configured to receive a consumable comprising a solid aerosol generating substrate, the substrate storage chamber comprising a heater according to the first aspect arranged on a surface of the heating chamber with the support surface facing into the substrate storage chamber.

Optionally, the aerosol generation device further comprises an air flow channel for drawing air through the aerosol generation device, wherein the heater is arranged between the substrate storage chamber and the air flow channel. This configuration provides a physical barrier between the substrate and the air flow channel, ensuring that the substrate does not enter the air flow channel and simplifying maintenance of the air flow channel.

Optionally, the heating element extends substantially across the whole of the surface of the substrate storage chamber.

Optionally, the aerosol generation device further comprises a compression element configured to compress the consumable against the heater. Compressing the substrate improves efficiency of heating and vapour/aerosol generation.

According to a third aspect, the present disclosure provides an aerosol generation system comprising a heater according to first aspect and a consumable, wherein the heating element protrudes from the surface of the ceramic base by at least <NUM>% of a thickness of the consumable.

<FIG> is a perspective schematic illustration of a heater <NUM>.

The heater comprises a base <NUM>, and a heating element <NUM> attached to a support surface of the base <NUM>. Specifically, in this example the heating element <NUM> is a first electrically conductive track.

The first electrically conductive track <NUM> is operable to generate heat by resistive heating when a current is passed along the track. The first electrically conductive track <NUM> may, for example, have a serpentine configuration in order to increase the length and resistance of the track. At each end <NUM> of the first electrically conductive track <NUM>, there is an electrical connector for attaching a power source to the first electrically conductive track <NUM>. In this embodiment, the electrical connector is a soldering pad, although any other type of electrical connector may be used.

The heater <NUM> also optionally comprises a second electrically conductive track <NUM> attached to the support surface of the base <NUM>. The second electrically conductive track <NUM> is used to sense a temperature based on a resistance-temperature characteristic of the second electrically conductive track <NUM>. In other words, by measuring a resistance value of the second track <NUM> and converting the resistance value to a temperature value using the resistance-temperature characteristic, a temperature is indirectly sensed by the second electrically conductive track <NUM>. The resistance-temperature characteristic may be measured specifically for the second electrically conductive track <NUM>, or may be calculated based on the materials and dimensions of the second electrically conductive track <NUM>. At each end <NUM> of the second electrically conductive track <NUM>, there is an electrical connector for attaching a power source to the second electrically conductive track <NUM>. In this embodiment, the electrical connector is a soldering pad, although any other type of electrical connector may be used.

The heating element <NUM> and the second electrically conductive track <NUM> may each be formed from an electrically conductive material such as copper or graphite.

More preferably, the heating element <NUM> (and optionally also the second electrically conductive track <NUM>) is formed from an inert material such as gold or platinum, which will not oxidise when heated.

The second electrically conductive track <NUM> is configured to have a higher electrical resistance than the heating element <NUM> at a given temperature (e.g. room temperature, <NUM>). The higher resistance increases the sensitivity of the second track <NUM> to temperature variation, whereas the lower resistance of the heating element <NUM> increases the current draw and the heating speed of the heating element <NUM>. The difference in resistance may be provided by using different materials. For example, the heating element <NUM> may comprise copper while the second electrically conductive track <NUM> comprises platinum, stainless steel or an electrically-conductive ceramic. Platinum in particular has the advantage that its resistance varies with temperature in a highly linear manner. Additionally or alternatively, the difference in resistance may be provided by using different dimensions for the tracks. For example, as shown in <FIG>, the second electrically conductive track <NUM> is longer and narrower than the first electrically conductive track <NUM>.

In some embodiments, rather than having two electrically conductive tracks that are specialised for the separate functions of heating and temperature sensing, a single electrically conductive track may perform both functions. In other words, the second electrically conductive track <NUM> may be omitted, and a temperature may be sensed by measuring a resistance of the first electrically conductive track <NUM> and by using a resistance-temperature characteristic of the first electrically conductive track <NUM>. Furthermore, a separate temperature sensor, not forming part of the structure of <FIG>, may be used.

Additionally, in some embodiments, two or more heating elements (e.g. electrically conductive tracks) may be independently configured for generating heat, allowing for a variable total heating rate by changing a number of heating elements which receive a power supply.

<FIG> is a schematic cross-section illustration of the heater <NUM> along the dashed line X marked in <FIG>. <FIG> is a schematic cross-section illustration of the heater <NUM> arranged in use to deliver heat to an aerosol generating substrate <NUM>.

The heating element <NUM> is operable to emit heat in use as shown in <FIG>, in order to deliver heat to the aerosol generating substrate <NUM>.

As the aerosol generating substrate <NUM> is heated, vapour forms which subsequently cools to form an aerosol.

The base <NUM> preferably comprises a porous material, such as a porous ceramic, and at least part of the support surface on which the heating element <NUM> is located is exposed to receive vapour or aerosol. A porous ceramic has pores through which vapour or aerosol may travel and thus the porous base can receive vapour or aerosol generated from the aerosol generating substrate <NUM>, providing additional space for vapour to form and cool into aerosol particles. Additionally, the porous ceramic can transport vapour or aerosol away from the aerosol generating substrate <NUM> and towards a site at which, for example, a user may inhale the aerosol. On the other hand, using a ceramic material has the advantage of high heat tolerance, meaning that the a porous ceramic can assist with vapour/aerosol generation without being damaged near to the heating element <NUM>. For example, the porous ceramic may be similar to the liquid conducting body described in <CIT>.

Alternatively, in some embodiments, the base <NUM> need not be porous, and may instead comprise a stainless steel such as steel grade <NUM> (<NUM>) or <NUM> (<NUM>). In such embodiments, electrical insulation may be located between the heating element <NUM> and the base <NUM>.

As shown in <FIG>, the heating element <NUM> may comprise a thick conductive track that protrudes from the support surface of the base <NUM>, in addition to extending along the support surface as shown in <FIG>. A thick conductive track of this kind forms a moulding surface which will deform a solid aerosol generating substrate, and thus reach closer to a centre of the substrate and deliver heat more efficiently to the substrate. In order to avoid lowering the resistance of the resistive track, the thick conductive track may be configured as a thin blade protrusion from the support surface.

As further shown in <FIG>, a protective layer <NUM> is provided to cover the heating element <NUM> and the second electrically conductive track <NUM>. The protective layer <NUM> is configured to protect the heating element <NUM> and the second electrically conductive track <NUM> from oxidizing when they becomes hot in use. Furthermore, a material for the protective layer <NUM> may be selected to be an electrical insulator in order to enable more dense packing of a winding route in the first and second electrically conductive tracks <NUM>, <NUM> without risk of short-circuit. The protective layer <NUM> may, for example, comprise silica, a polyimide, alumina, or a photoresist material. The protective layer <NUM> may have a thickness of, for example, <NUM>-<NUM>.

However, the protective layer <NUM> is preferably omitted in order to maximise thermal contact between the heating element <NUM> and the aerosol generating substrate <NUM>. This can be achieved if the heating element <NUM> is formed from an inert material that will not oxidise when hot.

In order to improve the correspondence between a temperature sensed by the second electrically conductive track <NUM> and a temperature caused by heat generation at the heating element <NUM>, the second electrically conductive tracks is preferably arranged nearby to the heating element <NUM>.

Correspondence between a temperature sensed by the second electrically conductive track <NUM> and a temperature caused by heat generation at the first electrically conductive track <NUM> is to arrange the first electrically conductive track <NUM> to surround the second electrically conductive track <NUM>. Referring again to <FIG>, the first electrically conductive track <NUM> forms an open loop between two electrical contacts at its ends <NUM>, which are arranged at a side of the heater assembly <NUM>. The second electrically conductive track <NUM> is confined between the first electrically conductive track <NUM> and the side of the layered heater assembly where the contacts <NUM> are located, meaning that the second electrically conductive track <NUM> is substantially surrounded by the first electrically conductive track <NUM>.

Advantageously, the second electrically conductive track <NUM> may similarly form an open loop between its two ends <NUM>, and electrical contacts for both tracks may be arranged along a single side of the heater.

Turning to <FIG>, the heater <NUM> is oriented for a use case where an aerosol generating substrate <NUM> rests on the heating element <NUM> and on the support surface of the base <NUM> of the heater <NUM>.

The aerosol generating substrate <NUM> is a solid substrate which may for example comprise nicotine or tobacco and an aerosol former. Here the term solid includes soft materials and loose materials, and used primarily to distinguish from liquid aerosol generating substrates <NUM>. 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 thick conductive track of a heating element <NUM> may protrude from the support surface by a protrusion distance of at least <NUM>% of a thickness D of the consumable. In absolute terms, the protrusions distance is preferably at least around <NUM>, and more preferably at least around <NUM>.

<FIG> is a schematic cross-section illustration of an alternative heater <NUM> along the dashed line X marked in <FIG>.

In the alternative heater <NUM> of <FIG>, the heater <NUM> additionally comprises an extension <NUM> protruding from the base <NUM> to form one or more moulding shapes or blade shapes that are configured to deform the aerosol generating substrate <NUM>.

In the alternative heater <NUM> of <FIG>, the heating element <NUM> need not be thick, and the moulding surface of the heating element <NUM> can simply comprise a planar heating element <NUM> laid on top of the extension <NUM>. For example, the extension <NUM> may protrude from the base <NUM> by a protrusion distance of at least around <NUM>, and more preferably protrude by at least around <NUM>. On the other hand, the heating element <NUM> may be a thin electrically conductive track with a thickness of as little as the order of <NUM> to <NUM>. In one specific example, the first electrically conductive track <NUM> has a thickness of <NUM> and the second electrically conductive track <NUM> has a thickness of <NUM>.

Preferably, the extension <NUM> is a monolithic part of the base <NUM>. In the case where the base <NUM> is porous, the extension <NUM> thus provides additional surface area for vapour/aerosol to travel out of the aerosol generating substrate <NUM> when the heating element <NUM> heats the aerosol generating substrate <NUM>.

<FIG> are schematic cross-sections of an example of an aerosol generating device <NUM> incorporating a heater assembly <NUM> as described above with reference to <FIG> or <FIG>, with lines x, y and z showing the relative planes of the cross-sections.

The aerosol generating device <NUM> comprises a first housing element <NUM> and a second housing element <NUM>. When the aerosol generating device <NUM> is in a closed position as shown in <FIG>, the first housing element <NUM> and the second housing element <NUM> together define a substrate storage chamber <NUM> in which a portion <NUM> of aerosol generating substrate aerosol is enclosed, and aerosol is generated from the portion <NUM> of aerosol generating substrate.

The first housing element <NUM> comprises a recess <NUM> (receiving means) for receiving the portion <NUM> of aerosol generating substrate, and the second housing element <NUM> comprises a lid surface <NUM> arranged to oppose a flat bottom surface <NUM> of the recess. The recess <NUM> may be substantially cuboid with a length L and width W in the plane of <FIG>, and a depth d. The portion <NUM> of aerosol generating substrate may correspondingly have a length L and width W, but may have a depth D.

Additionally, when the aerosol generating device <NUM> is in the closed position, the lid surface <NUM> is arranged to oppose the bottom surface <NUM> of the recess <NUM>, and in a case where the depth D of the portion <NUM> is larger than the depth d of the recess <NUM>, the portion <NUM> is compressed by the lid surface <NUM> towards the bottom surface <NUM> of the recess <NUM>. In this embodiment, the lid surface <NUM> is simply an extension of a surrounding flat surface of the second housing element <NUM>, and is the part of the flat surface which is arranged to oppose the bottom surface of the recess <NUM> in the closed position.

The heater assembly <NUM> is arranged to supply heat to the substrate storage chamber <NUM> at surface <NUM>, in order to heat the aerosol generating substrate and generate the aerosol. In other words, the support surface of the base <NUM> is arranged to correspond to the surface <NUM>, facing into the substrate storage chamber <NUM>. Preferably, the heating element <NUM> extends substantially across the whole of the surface <NUM>, in order to increase the surface area for delivering heat to the aerosol generating substrate <NUM>.

Compression between the surfaces <NUM> and <NUM>, in combination with the heater <NUM> of the invention, means that the compression causes the moulding surface of the heater <NUM> to deform the portion <NUM> of aerosol generating substrate according to the moulding surface of the heating element <NUM>. Because the pressure causes the heating element <NUM> to deform the portion <NUM>, the heating element <NUM> conforms to a larger surface area of the aerosol generating substrate <NUM>. Additionally, the compression of certain parts of the aerosol generating substrate according to the moulding surface improves the efficiency of heating the aerosol generating substrate.

However, compressing the aerosol generating substrate also reduces the spare volume in the aerosol generating substrate in which vapour/aerosol can form. A porous base <NUM> can compensate for this by providing additional porous volume in which the vapour/aerosol can form.

The portion <NUM> of aerosol generating substrate may optionally also comprise a pressure-activated heat generating element such as a capsule of ingredients for an exothermic reaction.

The device <NUM> also comprises an air flow channel <NUM> through the substrate storage chamber <NUM>, which is provided in order to extract the generated aerosol from the substrate storage chamber <NUM>. In the embodiment of <FIG>, the air flow channel <NUM> comprises an inlet <NUM> connected between the exterior of the device <NUM> and one end of the substrate storage chamber <NUM>, and an outlet <NUM> connected between the exterior of the device <NUM> and another end of the substrate storage chamber <NUM>. The exterior of the device <NUM> around the outlet <NUM> is configured as a mouthpiece so that a user can inhale air and aerosol through the device <NUM>. Alternatively, air may be artificially pumped through the air flow channel <NUM>, for example using a fan.

In the embodiment shown in <FIG>, the first and second housing members <NUM> and <NUM> are connected by one or more fasteners <NUM>, which are hinges in this case, along a pivot line that is approximately aligned with a length direction between the inlet <NUM> and the outlet <NUM>. By rotating on the hinges <NUM>, the first and second housing elements <NUM>, <NUM> move between an open position (shown in <FIG>) and a closed position (shown in <FIG>). In the open position, the recess <NUM> is exposed, and the portion <NUM> of aerosol generating substrate can be added or removed, and the device <NUM> (and in particular the heater assembly <NUM>) can be cleaned. In the closed position, the substrate storage chamber is completed and the aerosol can be generated. In other embodiments, the first and second housing members <NUM> and <NUM> may 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.

<FIG> is a perspective view of a first specific example of an aerosol generating device <NUM> in the open position, corresponding to the more general device illustrated in <FIG>.

In this example, each of the first and second housing elements <NUM>, <NUM> comprises an inner portion <NUM>, <NUM> and an outer portion <NUM>, <NUM>. The outer portions <NUM>, <NUM> provide an outer casing which is configured to be handheld. For example, the outer portions <NUM>, <NUM> may comprise a rigid metal casing supporting weaker inner portions <NUM>, <NUM>. Additionally or alternatively, the outer portions <NUM>, <NUM> may 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 channel <NUM> comprises a plurality of distinct inlets <NUM> (two in this case) in one end of the outer portion <NUM> of the second housing element <NUM>, to provide the inlet <NUM>. Air then flows into two channels extending in parallel, the channels being formed as grooves on a surface of the inner portion <NUM> of the second housing element <NUM> connected between the inlet and the outlet. The grooves are surrounded by and separated by portions of the compression surface <NUM>, with the effect of providing regions of improved aerosol generation adjacent to regions of improved airflow in the portion <NUM> of 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 device <NUM> in the closed position, this configuration creates a pressure gradient in the air flow channel <NUM> and reduces the air pressure adjacent to the portion <NUM> of aerosol generating substrate, further increasing aerosol generation.

Additionally, in the first specific example, the heater assembly (not shown in <FIG> but configured similarly to <FIG> at the flat bottom surface of the recess <NUM>) is driven by an external power source connected by electrical wire <NUM>. The device <NUM> can be manufactured for use with an external power source, by cutting or moulding space for the electrical wire <NUM> in the inner portion <NUM> of the first housing element <NUM>, and then providing a glue fill section <NUM> to separate the air flow channel <NUM> from the electrical wire <NUM>. Alternatively section <NUM> could be an additional solid component that is fitted in place, such as a snap-fit or press-fit component. In some embodiments, the electrical wire <NUM> connecting 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 device <NUM> comprises several closing means <NUM>, <NUM> and <NUM> for improving the closure of the device <NUM> in the closed position and thereby making the device <NUM> easier to operate with good aerosol generation.

Firstly, the first and second housing elements <NUM>, <NUM> are held in place in the closed position using one or more releasable fasteners (e.g. pairs of opposing magnets <NUM>) opposed to the hinge <NUM>. Providing releasable fasteners means that the device <NUM> need not be held in the closed position by hand throughout aerosol generation, making the device easier to use.

Secondly, tab surfaces <NUM> are provided which can be manually operated by a user's hand to open and close the device <NUM> between the open and closed positions. Providing the tab surfaces <NUM> means that the strength of the releasable fasteners can be increased without making it difficult for a user to move the device <NUM> from the closed position to the open position.

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

<FIG> is a schematic illustration of a second specific example of the aerosol generating device in an open position.

In the second specific example, first and second housing elements <NUM>, <NUM> are connected by a pivot line that is perpendicular to a length direction between an inlet <NUM> and an outlet <NUM>. In this case, the inlet may be a gap between the first and second housing elements <NUM>, <NUM> along the pivot line.

Additionally, in order to improve a seal provided by gasket <NUM>, the gasket is arranged to engage with an outer recess wall <NUM> of the first housing element <NUM> extending around the recess <NUM> and the heater assembly <NUM>.

Furthermore, as shown in <FIG>, in some embodiments, the electrical wire <NUM> connecting to an external power source can be replaced with an internal power source <NUM>. With an internal power source, the aerosol generating device <NUM> can be provided as a portable handheld device. In the example of <FIG>, the internal power source <NUM> is provided in an extended inlet portion <NUM> of the device <NUM>, although other arrangements of the internal power source would be apparent to the skilled person.

<FIG> are schematic cross-sections of an alternative example of an aerosol generating device <NUM> incorporating a heater <NUM> as described above with reference to <FIG> or <FIG>, with lines x, y and z showing the relative planes of the cross-sections.

The alternative example is largely similar to the example described above with reference to <FIG>, and only the differences are described here.

In the alternative example, the heater <NUM> is arranged between the substrate storage chamber <NUM> and the air flow channel <NUM>, as shown in <FIG>.

As mentioned above, the base <NUM> of the heater <NUM> in some embodiments incorporates a porous material such as a porous ceramic. As such, vapour and/or aerosol can travel through the porous structure of the base <NUM> to the air flow channel <NUM>.

As an addition or alternative to the porous structure of the bulk material of the base, the base <NUM> may comprise one or more specifically constructed ducts through which vapour and/or aerosol may travel from the substrate storage chamber <NUM> to the air flow channel <NUM>.

As air is drawn along the air flow channel <NUM>, the pressure in the air flow channel <NUM> may be reduced adjacent to the base <NUM>, further drawing vapour and/or aerosol into the air flow channel <NUM>, through the porous structure or ducts.

In order to accommodate this rearrangement of the heater <NUM>, the first housing element <NUM> and a second housing element <NUM> may be configured to divide the device <NUM> in a plane which does not include the air flow channel <NUM>, contrary to the first example of <FIG>.

Specifically, the plane of the open aerosol generating device <NUM> shown in <FIG> corresponds to the lines x and z illustrated in <FIG>, and this plane is separated from the air flow channel <NUM>, meaning that the air flow channel <NUM> is now fully enclosed within the first housing element <NUM>.

Claim 1:
A heater (<NUM>) for heating a consumable comprising a solid aerosol generating substrate (<NUM>), the heater comprising:
a base (<NUM>); and
a heating element (<NUM>) attached to a support surface of the base,
wherein the heating element comprises a moulding surface configured to deform and heat the aerosol generating substrate, and
wherein the heating element comprises a thick conductive track extending along and protruding from the support surface.