TECHNICAL FIELD

The present invention relates an aerosol provision device, an aerosol provision system and a method of generating an aerosol.

BACKGROUND

Smoking articles such as cigarettes, cigars and the like burn tobacco during use to create tobacco smoke. Attempts have been made to provide alternatives to these articles by creating products that release compounds without combusting. Examples of such products are so-called “heat not burn” products or tobacco heating devices or products, which release compounds by heating, but not burning, material. The material may be, for example, tobacco or other non-tobacco products, which may or may not contain nicotine.

Aerosol provision systems, which cover the aforementioned devices or products, are known. Common systems use heaters to create an aerosol from a suitable medium which is then inhaled by a user. Often the medium used needs to be replaced or changed to provide a different aerosol for inhalation. It is known to use resistive heating systems as heaters to create an aerosol from a suitable medium. Separately induction heating systems are known to be used as heaters.

SUMMARY

According to an aspect there is provided an aerosol provision device comprising: a heater element having an outer diameter Dp, a volume Vp and an outer surface area Sp, wherein the heater element is configured to be inserted into an article, wherein the article comprises a first cylindrical portion comprising aerosol generating material, wherein the first cylindrical portion has an outer diameter De, a volume Vc and an outer curved surface area Sc; and wherein Sc/Sp is in the range 3.6-4.2.

Optionally, the heater element comprises a pin-shaped heater element.

Optionally, the pin-shaped heater element comprises a cylindrical body and a conical tip.

Optionally, the pin-shaped heater element comprises an elongate body having a cavity and one or more heater coils arranged within the cavity. Optionally, the heater element comprises a blade-shaped heater element.

Optionally, the blade-shaped heater element comprises one or more conductive or resistive tracks. The conductive or resistive tracks may comprise NiChrome (Ni20Cr80).

Optionally, the heater element comprises a resistive heater element.

Optionally, the heater element comprises an inductive heater element.

Optionally, Dc/Dp is in the range 3.1-3.6.

Optionally, Dc/Dp is in the range 3.2-3.5.

Optionally, Dc/Dp is in the range 3.3-3.4.

Optionally, Vc/Vp is in the range 11.0-16.0.

Optionally, Vc/Vp is in the range 12.0-15.0.

Optionally, Vc/Vp is in the range 13.0-14.0.

Optionally, Vc/Vp, shell is in the range 31.0-131.0.

Optionally, Vc/Vp, shell is in the range 81.0-131.0.

Optionally, Vc/Vp shell is in the range 101.0-131.0.

Optionally, Sc/Sp is in the range 3.7-4.1.

Optionally, Sc/Sp is in the range 3.8-4.0.

The aerosol provision device may further comprise a controller configured to control the heater element during a session of use, wherein during a session of use the controller is configured to control the heater element to heat to a first target operating temperature T 1 during a first time period tO-t1 , to heat to a second target operating temperature T2 during a second time period t1-t2, to heat to a third target operating temperature T3 during a third time period t2-t3 and to heat to a fourth target operating temperature T4 during a fourth time period t3-t4, wherein time to < t1 < t2 < t3 < t4 Optionally, temperature T1 > T2 > T3 > T4. Optionally, T4 > 300 °C. According to another aspect there is provided an aerosol provision system comprising: an aerosol provision device as described above; and an article comprising aerosol generating material.

Optionally, the article comprising aerosol generating material may comprise bandcast reconstituted tobacco.

According to another aspect there is provided a method of generating an aerosol comprising: providing an aerosol provision device as described above; at least partially inserting an article comprising aerosol generating material into a receiving portion of a heating chamber of the aerosol provision device; and activating the aerosol provision device in order to generate aerosol from the article.

The aerosol provision device may comprise a controller which is arranged to set target operating temperatures for the heater element according to a heating profile. The heating profile may comprise an initial first target operating temperature after which the heating profile may progressively step down during the course of a session of use or an aerosol generation session. In particular, the heating profile may have a profile wherein the desired operating temperature which is set for the heater element may be arranged to step down in a series of e.g. four steps during the course of a session of use or an aerosol generation session. The heating profile having e.g. four steps down as a progression of time may correspond with a first, standard or regular mode of operation known as a “base” mode of operation. When the aerosol provision device is operating in a first or base mode of operation, an aerosol generation session may be arranged to last for, for example, 300 s (5 mins).

According to various embodiments a session of use may commence at a time to and may end at a time t4 when the controller may switch the heater element OFF. Once a session of use has been commenced at time to, there may be a ramp up time or time to first puff before an aerosol may be generated. The ramp up time or time to first puff may end at a time t_start. An aerosol generation session may be considered as commencing at a time t_start and may, for example, be considered as ending at a time t4 when the heater element may be switched OFF.

The aerosol provision device may be operated in a second mode of operation known as a “boost” mode of operation. When the aerosol provision device is operated in a second or boost mode of operation, the session of use and corresponding aerosol generation session time may be shorter. For example, the length of an aerosol generation session may be shortened to, for example, 180 s (3 mins). According to various embodiments during the first operating mode and/or during the second operating mode the temperature set for heater element may remain > 300 °C throughout the entirety of the session of use (and hence also throughout the entirety of an aerosol generation session). A maximum operating temperature of the heater element during a session of use (and hence during an aerosol generation session) may be higher when the aerosol provision device is operated in a second or boost mode of operation compared with the maximum operating temperature of the heater element when operated in a first or base mode of operation. According to various embodiments, the maximum operating temperature may be approx. 350 °C. According to various embodiments the controller may be arranged to seek to maintain the temperature of the heater element in the range 300-350 °C during a session of use.

The heater element may be arranged to internally heat an aerosol generating article. Alternatively, the heater element may be arranged to externally heat an aerosol generating article.

The aerosol provision device may comprise a power source, a controller and a heating chamber in which an aerosol generating article is removeable received. The aerosol provision device may be configured for wireless charging.

The aerosol provision device may comprise one or more indicator devices or signalling devices for indicating or signalling to a user when the heater element has reached a desired operating temperature and/or when the aerosol provision device is ready to use e.g. after an initial ramp up time. For example, the one or more indicator devices or signalling devices may be arranged to be activated or change state at time t_start i.e. after an initial ramp up time or time to first puff.

An aerosol provision system may be provided comprising an aerosol provision device as described above in combination with a charging unit. The charging unit may comprise a cavity for removably receiving the aerosol provision device. The charging unit may comprise a moveable cover which is configured to cover the aerosol provision device in a closed configuration. The charging unit may comprise a user display. The user display may be visible to a user when the moveable cover is in a closed position and may be partially or fully concealed or obscured from sight by the cover when the cover is an open position.

The aerosol provision device may comprise a controller and a user interface. The user interface may be activated by a user to cause the aerosol provision device to operate in a first (e.g. base) mode of operation wherein the controller is configured to control the heater element so that the heater element heats to a series of target operating temperatures according to a first heating profile as a function of time. The user interface may also be activated by a user to cause the aerosol provision device to operate in a second (e.g. boost) mode of operation wherein the controller is configured to control the heater element so that the heater element heats to a series of target operating temperatures according to a second different heating profile as a function of time. The first heating profile may relate to a session of use having a total duration tuotai and wherein the heater element may be set target operating temperatures between a minimum target operating temperature Timin and a maximum target operating temperature Timax. The second heating profile may relate to a session of use having a total duration tuotai and wherein the heater element may be set target operating temperatures between a minimum target operating temperature T2min and a maximum target operating temperature T2max. The duration of an aerosol generation session may correspond with the period of time subsequent to an initial time to first puff (or ramp up time) i.e. from a time t_start onwards through to a time corresponding to the end of an aerosol generation session when no aerosol is intended to be generated. At the end of an aerosol generation session the controller may set a target operating temperature for the heater element which is too low to cause an aerosol to be generated e.g. 20°C. At the end of an aerosol generation session the heater element may be switched OFF i.e. zero current may be supplied to the heater element. According to various embodiments tuotai > t2totai and/or T2max > Timax and/or T2min > Timin. According to various embodiments Ti min — 300 °C and/or T2min s 300 °C.

The aerosol provision device may further comprise a temperature sensor for monitoring or sensing the temperature of the heater element during the course of session of use or an aerosol generation session. The temperature sensor may comprise a thermocouple, a thermopile or a resistance temperature detector (“RTD”) which may also be referred to as a resistance thermometer. Temperature data measured by the temperature sensor may be communicated to the controller. In particular, when the temperature sensor determines that the heater element has reached a target operating temperature (e.g. T1 , T2, T3 or T4) at a point in time during a session of use the controller may be arranged to change the supply of power to heater element. The controller may comprise a proportional integral derivative (“PID”) controller which uses a control feedback loop mechanism to control the temperature of the heater element based on data, information or signal(s) supplied from the one or more temperature sensors.

The article comprising aerosol generating material may comprise a capsule which may be fragmented in order to introduce an additional flavourant or other agent into an aerosol generated in an aerosol generating portion of the article. The article may comprise one or more filters which may comprise e.g. cellulose acetate. The article may comprise one or more ventilation holes formed through an outer layer of the article to aid with cooling of the article. The one or more ventilation holes may be provided > 5 mm from the proximal (mouth) end of the article.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments will now be described, by way of example only, and with reference to the accompanying drawings, in which:

Fig. 1 shows a perspective view of an aerosol provision system comprising an aerosol provision device located within a charging unit, wherein the aerosol provision device comprises a heater element;

Fig. 2 shows a schematic cross-sectional view of part of the aerosol provision device as shown in Fig. 1 , wherein the aerosol provision device comprises a pin-shaped heater element;

Fig. 3 shows a schematic cross-sectional view of part of the aerosol provision device as shown in Fig. 1 and an aerosol generating article, wherein the pin-shaped heater element is shown inserted into a distal end of the aerosol generating article;

Fig. 4 shows a perspective view of standalone aerosol provision device according to another embodiment, wherein the standalone aerosol provision device may be charged directly rather than being charged by a charging unit into which the aerosol provision device is inserted;

Fig. 5 shows a schematic cross-sectional view of the aerosol provision device as shown in Fig. 4 and shows that the aerosol provision device may comprise a pin-shaped heater element which, in use, may be inserted into a distal end of an aerosol generating article;

Fig. 6 shows a schematic cross-sectional view of a pin-shaped heater element which may be used to heat an aerosol generating article according to various embodiments;

Fig. 7A shows a standalone or one-piece aerosol provision device according to an embodiment with an aerosol generating article shown partially inserted into a heating chamber of the aerosol provision device and Fig. 7B shows a cross-sectional view of internal detail of the aerosol provision device shown in Fig. 7A and shows a pin-shaped heater element inserted into a distal end of a cylindrical aerosol generating article, wherein the aerosol generating article comprises a first portion and further portions, and wherein the pin-shaped heater element is shown inserted into the first portion of the aerosol generating article;

Fig. 8A illustrates a first computer aided design (“CAD”) model of a pin-shaped heater element surrounded by a first cylindrical portion of an aerosol generating article and Fig. 8B shows a simplified second CAD model which was utilised in computational fluid dynamics (“CFD”) simulations, wherein the simplified second CAD model comprised a consumable which was modelled as being held in a consumable holder, a pin-shaped heater element and wherein a number of air inlets were modelled as being provided in a base portion of the consumable holder;

Fig. 9 shows a heating profile which was utilised in various computational fluid dynamics (CFD) simulations, wherein the heating profile illustrates the temperature which the pin-shaped heater element was modelled as obtaining during the course of a simulation which was modelled as lasting 300 s (5 mins) and wherein the heating profile comprised four steps down in temperature during the course of the simulation;

Fig. 10 illustrates a pin-shaped heater element which was modelled in CAD to permit various CFD simulations to be performed, wherein a coil heater element was modelled as being located within a pin-shaped heater element, wherein the pin-shaped heater element had a diameter Dp and a wall thickness Tp, wherein the length of the pin was modelled as being Lp, with the coil heater element being displaced a distance Lh from a reference point, and wherein a cylindrical consumable portion was modelled as surrounding the pin-shaped heater element, wherein the cylindrical consumable portion was modelled as having a length Lc and a diameter De;

Fig. 11 shows a table illustrating various parameters of the pin-shaped heater element shown in Fig. 10 together with minimum and maximum values of the parameters were used in various CFD simulations;

Fig. 12A shows an image from a CFD simulation of the pin-shaped heater element and consumable as were modelled with reference to the parameters shown in Figs. 10 and 11 and illustrates that an average volume temperature in the consumable Tvoi.avg.c may be determined from the CFD simulations;

Fig. 12B shows how the average volume temperature in the consumable Tvoi.avg.c was determined from CFD simulations to vary as a function of the ratio of the diameter of the consumable (De) to the diameter of the pin-shaped heater element (Dp) at a point in time corresponding to taking a tenth puff from the consumable;

Fig. 12C shows how the average volume temperature in the consumable T _vo i.avg.c was determined from CFD simulations to vary as a function of the ratio of the volume of the consumable (Vc) to the volume of the pin-shaped heater element (Vp) at a point in time corresponding to taking a tenth puff from the consumable;

Fig. 12D shows how the average volume temperature in the consumable T _vo i.avg.c was determined from CFD simulations to vary as a function of the ratio of the surface area of the consumable (Sc) to the surface area of the pin-shaped heater element (Sp) at a point in time corresponding to taking a tenth puff from the consumable;

Fig. 12E shows how the average volume temperature in the consumable Tvoi.avg.c was determined from CFD simulations to vary as a function of the ratio of the volume of the consumable (Vc) to the volume of the pin-shaped heater element (Vp, shell) at a point in time corresponding to taking a tenth puff from the consumable;

Fig. 13A shows an image from a CFD simulation of the pin-shaped heater element and consumable as were modelled with reference to the parameters shown in Figs. 10 and 11 and illustrates that an outer surface average temperature of the consumable Tsurf.avg.c may be determined from the CFD simulations;

Fig. 13B shows how the outer surface average temperature of the consumable Tsurf.avg.c was determined from CFD simulations to vary as a function of the ratio of the diameter of the consumable (De) to the diameter of the pin-shaped heater element (Dp) at a point in time corresponding to taking a tenth puff from the consumable;

Fig. 13C shows how the outer surface average temperature of the consumable Tsurf.avg.c was determined from CFD simulations to vary as a function of the ratio of the volume of the consumable (Vc) to the volume of the pin-shaped heater element (Vp) at a point in time corresponding to taking a tenth puff from the consumable;

Fig. 13D shows how the outer surface average temperature of the consumable Tsurf.avg.c was determined from CFD simulations to vary as a function of the ratio of the surface area of the consumable (Sc) to the surface area of the pin-shaped heater element (Sp) at a point in time corresponding to taking a tenth puff from the consumable;

Fig. 13E shows how the outer surface average temperature of the consumable Tsurf.avg.c was determined from CFD simulations to vary as a function of the ratio of the volume of the consumable (Vc) to the volume of the pin-shaped heater element (Vp, shell) at a point in time corresponding to taking a tenth puff from the consumable;

Fig. 14 is a side-on cross sectional view of an aerosol generating article partially inserted into a receiving portion or recess of an aerosol provision device according to various embodiments, wherein the aerosol provision device comprises a pin-shaped heater element; and

Fig. 15 is a cross sectional view of the aerosol generating article shown in Fig. 14 taken along line A-A’ as shown in Fig. 14.

DETAILED DESCRIPTION

According to the present disclosure, a “non-combustible” aerosol provision system is one where a constituent aerosol generating material of the aerosol provision system (or component thereof) is not combusted or burned in order to facilitate delivery of at least one substance to a user.

In some embodiments, the delivery system is a non-combustible aerosol provision system, such as a powered non-combustible aerosol provision system.

In some embodiments, the non-combustible aerosol provision system is an electronic cigarette, also known as a vaping device or electronic nicotine delivery system (END), although it is noted that the presence of nicotine in the aerosol generating material is not a requirement.

In some embodiments, the non-combustible aerosol provision system is an aerosol generating material heating system, also known as a heat-not-burn system. An example of such a system is a tobacco heating system.

In some embodiments, the non-combustible aerosol provision system is a hybrid system to generate aerosol using a combination of aerosol generating materials, one or a plurality of which may be heated. Each of the aerosol generating materials may be, for example, in the form of a solid, liquid or gel and may or may not contain nicotine. In some embodiments, the hybrid system comprises a liquid or gel aerosol generating material and a solid aerosol generating material. The solid aerosol generating material may comprise, for example, tobacco or a non-tobacco product.

Typically, the non-combustible aerosol provision system may comprise a non-combustible aerosol provision device and a consumable for use with the non- combustible aerosol provision device.

In some embodiments, the non-combustible aerosol provision device may comprise an area for receiving the consumable, an aerosol generator, an aerosol generation area, a housing, a mouthpiece, a filter and/or an aerosol-modifying agent. In some embodiments, the consumable for use with the non-combustible aerosol provision device may comprise aerosol generating material, an aerosol generating material storage area, an aerosol generating material transfer component, an aerosol generator, an aerosol generation area, a housing, a wrapper, a filter, a mouthpiece, and/or an aerosol-modifying agent.

As used herein, the term “aerosol generating material” is a material that is capable of generating aerosol, for example when heated, irradiated or energized in any other way. Aerosol-generating material may, for example, be in the form of a solid, liquid or semi-solid (such as a gel) which may or may not contain an active substance and/or flavourants.

The aerosol generating material may comprise one or more active substances and/or flavours, one or more aerosol-former materials, and optionally one or more other functional material.

The aerosol generating material may comprise a binder, such as a gelling agent, and an aerosol former. Optionally, a substance to be delivered and/or filler may also be present. Optionally, a solvent, such as water, is also present and one or more other components of the aerosol generating material may or may not be soluble in the solvent. In some embodiments, the aerosol generating material is substantially free from botanical material. In particular, in some embodiments, the aerosol generating material is substantially tobacco free.

The aerosol generating material may comprise or be in the form of an aerosol generating film. The aerosol generating film may comprise a binder, such as a gelling agent, and an aerosol former. Optionally, a substance to be delivered and/or filler may also be present. The aerosol generating film may be substantially free from botanical material. In particular, in some embodiments, the aerosol generating material is substantially tobacco free.

The aerosol generating film may have a thickness of about 0.015 mm to about 1 mm. For example, the thickness may be in the range of about 0.05 mm, 0.1 mm or 0.15 mm to about 0.5 mm or 0.3 mm.

The aerosol generating film may be continuous. For example, the film may comprise or be a continuous sheet of material. The sheet may be in the form of a wrapper, it may be gathered to form a gathered sheet or it may be shredded to form a shredded sheet. The shredded sheet may comprise one or more strands or strips of aerosol generating material. The aerosol generating film may be discontinuous. For example, the aerosol generating film may comprise one or more discrete portions or regions of aerosol generating material, such as dots, stripes or lines, which may be supported on a support. In such embodiments, the support may be planar or non-planar.

The aerosol generating film may be formed by combining a binder, such as a gelling agent, with a solvent, such as water, an aerosol-former and one or more other components, such as one or more substances to be delivered, to form a slurry and then heating the slurry to volatilise at least some of the solvent to form the aerosol generating film.

An aerosol provision device can receive an article comprising aerosol generating material for heating. An “article” in this context is a component that includes or contains in use the aerosol generating material, which is heated to volatilise the aerosol generating material, and optionally other components in use. A user may insert the article into or onto the aerosol provision device before it is heated to produce an aerosol, which the user subsequently inhales. The article may be, for example, of a predetermined or specific size that is configured to be placed within or over a heater of the device which is sized to receive the article.

An aerosol generator is an apparatus configured to cause aerosol to be generated from the aerosol generating material. In some embodiments, the aerosol generator is a heater configured to subject the aerosol generating material to heat energy, so as to release one or more volatiles from the aerosol generating material to form an aerosol. In some embodiments, the aerosol generator is configured to cause an aerosol to be generated from the aerosol generating material without heating. For example, the aerosol generator may be configured to subject the aerosol generating material to one or more of vibration, increased pressure, or electrostatic energy.

A consumable is an article comprising or consisting of aerosol generating material, part or all of which is intended to be consumed during use by a user. A consumable may comprise one or more other components, such as an aerosol generating material storage area, an aerosol generating material transfer component, an aerosol generation area, a housing, a wrapper, a mouthpiece, a filter and/or an aerosolmodifying agent. A consumable may also comprise an aerosol generator, such as a heater, that emits heat to cause the aerosol generating material to generate aerosol in use. The heater may, for example, comprise combustible material, a material heatable by electrical conduction, or a susceptor. A susceptor is a heating material that is heatable by penetration with a varying magnetic field, such as an alternating magnetic field. The susceptor may be an electrically-conductive material, so that penetration thereof with a varying magnetic field causes induction heating of the heating material. The heating material may be magnetic material, so that penetration thereof with a varying magnetic field causes magnetic hysteresis heating of the heating material. The susceptor may be both electrically- conductive and magnetic, so that the susceptor is heatable by both heating mechanisms. The susceptor may be only magnetic, or only electrically-conductive. The aerosol provision device that is configured to generate the varying magnetic field is referred to as a magnetic field generator, herein.

Non-combustible aerosol provision systems may comprise a modular assembly including both a reusable aerosol provision device and a replaceable aerosol generating article. In some implementations, the non-combustible aerosol provision device may comprise a power source and a controller (or control circuitry). The power source may, for example, comprise an electric power source, such as a battery or rechargeable battery. In some implementations, the non-combustible aerosol provision device may also comprise an aerosol generating component. However, in other implementations the aerosol generating article may comprise partially, or entirely, the aerosol generating component.

The present disclosure relates to an aerosol provision device as described below with reference to Figs. 1-6. The aerosol provision device may comprise a controller and a heater element, such as a pin-shaped heater element. The controller may be arranged to set the heater element a series of different target operating temperatures according to a heating profile such as the heating profile shown in Fig. 9. According to various embodiments the aerosol provision device comprises a heater element having an outer diameter Dp, a volume Vp and an outer surface area Sp, wherein the heater element is configured to be inserted into an article, wherein the article comprises a first cylindrical portion comprising aerosol generating material, wherein the first cylindrical portion has an outer diameter De, a volume Vc and an outer curved surface area Sc. It is has been that there are various optimum ratios for the above parameters. For example, according to various embodiments if Dc/Dp is in the range 3.1-3.6 then CFD simulations show that optimum performance in terms of various temperatures related to the consumable is achieved. Similarly, it has been found that optimally Vc/Vp should be in the range 11. CI- 16.0. In addition, it has been found that optimally Sc/Sp should be in the range 3.6-4.2.

Fig. 1 shows an aerosol provision system 10 comprising an aerosol provision device 100 and a charging unit 101. The device is shown located within a cavity of a charging unit 101. The aerosol provision device 100 is arranged to generate aerosol from an aerosol generating article which may be inserted, in use, into the aerosol provision device 100. The aerosol provision device 100 and an article may together form part of an aerosol provision system 10.

As will be discussed in more detail below, the aerosol provision device 100 comprises a heater element. For example, the aerosol provision device 100 may comprise a pin-shaped heater element as will be described in more detail below. The aerosol provision device may further comprise a controller which may be configured to control the heater element during a session of use. During a session of use the controller may be configured to control the heater element so as that the heater element assumes a first target operating temperature T 1 during a first time period tO-t1 , a second target operating temperature T2 during a second time period t1-t2, a third target operating temperature T3 during a third time period t2-t3 and a fourth target operating temperature T4 during a fourth time period t3-t4. According to various embodiments the controller may arrange for the target operating temperature to step down in temperature during the course of a session of use. For example, temperature T1 > T2 > T3 > T4. According to embodiments T4 > 300 °C. Accordingly, the controller may be configured to cause the heater element to heat to a series of target operating temperatures during session of use wherein the target operating temperatures progressively step down as function of time. For example, the heater element may be controlled by the controller to follow a heating profile wherein the target operating temperature steps down four times during the course of a session of use. According to embodiments at all times the target operating temperature of the heater element during a session of use may be > 300 °C.

At an initial time to, the aerosol provision device 100 and the heater element may be at ambient temperature e.g. 20 °C. Other embodiments are contemplated wherein a previous aerosol generation session has been performed and wherein the temperature of the heater element has dropped to a temperature < 50 °C. Accordingly, at an initial time tO the heater element may be at a temperature < 50 °C.

The aerosol provision device 100 may comprise an elongate structure extending along a longitudinal axis. The aerosol provision device 100 has a proximal end, which is closest to the user (e.g. the user’s mouth) when in use by the user to inhale aerosol generated by the aerosol provision device 100. The aerosol provision device 100 also has a distal end which will be furthest from the user when in use. The proximal end may also be referred to as the “mouth end”. The aerosol provision device 100 comprises an opening which leads into a heating chamber.

The aerosol provision device 100 may be removably inserted into the charging unit 101 in order to be charged. However, as discussed in more detail below the aerosol provision device may comprise a standalone aerosol provision device which can be charged directly without requiring a charging unit 101 to recharge the aerosol provision device.

The charging unit 101 comprises a cavity for receiving the aerosol provision device 100. The aerosol provision device 100 may be inserted into the cavity of the charging unit 101 via an opening. The cavity of the charging unit 101 may comprise a longitudinal opening. A portion of the aerosol provision device 100 may comprise a first side. One or more user-operable control elements such as buttons 106 which may be activated in order to operate the aerosol provision device 100 (and in particular to select a desired mode of operation) may be provided on the first side of the aerosol provision device 100. The first side of the aerosol provision device 100 may be received in the longitudinal opening provided in the charging unit 101.

The cavity of the charging unit 101 may have a cross-sectional profile which only permits that the aerosol provision device 100 be inserted into the charging unit 101 in a single orientation. The outer profile of the aerosol provision device 100 may comprise an arcuate portion and a linear portion. The cross-sectional profile of the cavity provided in the charging unit 101 may also comprise a similar arcuate portion and a linear portion. The linear portion of the cross-sectional profile of the cavity may correspond with the longitudinal opening. The charging unit 101 may include a slidable cover 103. When the aerosol provision device 100 is inserted into the charging unit 101 in order to be recharged, the slidable cover 103 may be closed so as to cover the opening into the aerosol provision device 100. In other embodiments, the charging unit 101 may have an alternative cover configuration, such as a hinged or pivoted cover, or no cover may be provided. The charging unit 101 may include a user interface such as display 108, which may be provided at any convenient location, such as in the position shown in Fig. 1.

Fig. 2 shows a cross sectional view of a portion of an aerosol provision device 100 according to various embodiments. The aerosol provision device 100 comprises a main housing 200. The main housing 200 defines a device body of the device 100. The aerosol provision device 100 defines a heating chamber 201. A receptacle 205 may be provided which defines a heating chamber 201. An opening 203 may be provided to provide access to the heating chamber 201. The receptacle 205 may comprise a receptacle side wall 205a and a receptacle base 205b. The receptacle base 205b may be provided at the distal end of the receptacle 205. A heating zone 201a may be provided which is configured to receive at least a portion of an aerosol generating article. A heater element 301 may be provided in a portion of the main housing 200 and the heater element 301 may extend or project into the heating chamber 201. The heater element 301 may comprise a base portion 301a which may be located in a recess provided in a portion of the body of the aerosol provision device 100.

The heater element 301 may comprise an elongate heater element such as a pin- shaped heater element 301. The pin-shaped heater element 301 may comprise a metal such as stainless steel or aluminium. Alternatively, the pin-shaped heater element 301 may comprise a ceramic material. Other embodiments are contemplated wherein the heater element may comprise a blade-shaped heater element (not shown). The heater element 301 may be inserted, in use, into a distal end of an aerosol generating article which is received within the heating chamber 201 in order to internally heat the aerosol generating article.

The housing 200 may comprise a housing wall 200a. The housing wall 200a may extend along the longitudinal axis of the aerosol provision device 100 and may surround the heating chamber 201. The housing wall 200a may, at least in part, define a receiving chamber of the aerosol provision device 100, as the volume which is enclosed within the wall 200a. The housing 200 may comprise a housing base 200b at the distal end of the housing wall 200a. The heater element 301 may be arranged so as upstand from the housing base 200b. The heater element 301 may be arranged so as to protrude through the receptacle base 205b. An aperture 206 may be formed in the receptacle base 205b through which the heater element 301 may protrude. The heater element 301 may be mounted to the receptacle base 205b.

The aerosol provision device 100 may optionally comprise a removal mechanism 204 which may be removably retained to the main housing 200 of the aerosol provision device 100. However, according to other embodiments the removal mechanism 204 may be omitted. The removal mechanism 204 may comprise a tubular wall portion 207a and a base wall portion 207b. After an aerosol generation session has been completed, the removal mechanism 204 may be removed from the main housing 200 of the aerosol provision device 100. As the removal mechanism 204 is removed, the base wall portion 207b of the removal mechanism 204 may be arranged to engage with a distal end of an article which has been located on the pin-shaped heater element 301 so that as the removal mechanism is removed, the base wall portion 207b of the removal mechanism dislodges a spent aerosol generating article from the heater element 301. As a result, the removal mechanism 204 may assist in removing a spent aerosol generating article from a heater element such as a pin-shaped heater element 301.

Fig. 3 shows the distal end of an article 50 comprising aerosol generating material located on a pin-shaped heater element 301 of an aerosol provision device 100.

Fig. 4 shows a one-piece aerosol provision device 400 for generating aerosol from an article 50 comprising aerosol generating material. The aerosol provision device 400 comprises an elongate housing 500 which surrounds and houses various components of the aerosol provision device 400. The aerosol provision device 400 has an opening 504 at one end through which the article 50 may be inserted for heating by the aerosol provision device 400. The article 50 may be fully or partially inserted into the aerosol provision device 400 for heating by the aerosol provision device 400. The aerosol provision device 400 may comprise a user-operable control element 506, such as a button or switch, for operating the aerosol provision device 400. For example, the user-operable control element 506 may be pressed in order to cause the aerosol provision device 400 to enter either a first operating mode or a second operating mode. The aerosol provision device 400 defines a longitudinal axis 509 along which an article 50 may extend when inserted into the aerosol provision device 400. The opening 504 is aligned on the longitudinal axis 509.

As will be discussed in more detail below, the aerosol provision device 400 may be operated in a first or base operating mode wherein the desired operating temperature of a heater element may, for example, be arranged to step down in a series of e.g. four steps during the course of an aerosol generation session which may last, for example, 300 s (5 mins). The aerosol provision device 400 may also be operated in a second or boost operating mode wherein the desired operating temperature of the heater element may also be arranged to step down in a series of e.g. four steps over a shorter time period of time. For example, the aerosol generation session may be arranged to last, for example, 180 s (3 mins) in the second or boost operating mode. The maximum operating temperature of the heater element during a session of use or an aerosol generation session may be higher when the aerosol provision device is operated in a second or boost mode of operation.

Fig. 5 shows a cross-sectional schematic view of an aerosol provision device 400 with an aerosol generating article 50 received within a heating chamber of the aerosol provision device 400. The aerosol provision device 400 comprises a power source 410, a controller 420 and a heating chamber 401 in which the aerosol generating article 50 is removeable received. The aerosol provision device 400 further comprises a heater element. The a heater element may comprise a heater element 301. The controller 420 may be configured so as to control the heater element 301 to heat to a first target operating temperature T 1 during a first time period tO-t1 , to heat to a second target operating temperature T2 during a second time period t1-t2, to heat to a third target operating temperature T3 during a third time period t2-t3 and to heat to a fourth target operating temperature T4 during a fourth time period t3-t4. The temperatures T1 > T2 > T3 > T4 and time to < t1 < t2 < t3 < t4. The heater element 301 may be inserted, in use, into a distal end of the aerosol generating article 50 which is received within the heating chamber 401 in order to internally heat the aerosol generating article 50.

The aerosol provision device 400 may comprise a resistive heater element such as a resistive heating coil which is arranged to be actuated to heat the heater element 301. An electrical current may be applied directly to the resistive heater element, and the resulting flow of current in the heater element may cause the heater element to be heated by Joule heating. The resistive heater element may comprise resistive material which is configured to generate heat when a suitable electrical current is passed through it. The aerosol provision device 400 may further comprise electrical contacts for supplying electrical current to the resistive material. The resistive heater element may be arranged to transfer thermal energy to the heater element 301 by conduction. Similarly, the heater element 301 may transmit thermal energy to a portion of the aerosol generating article 50 by conduction. The provision of a resistive heating arrangement allows for a compact arrangement to be achieved thereby facilitating device miniaturisation. Furthermore, heating a portion of an aerosol generating article 50 using a resistive heater element such as a pin-shaped heater element 301 wherein the pinshaped heater element 301 is inserted into a distal end of the aerosol generating article enables a high energy efficiency to be achieved since thermal losses can be minimised.

Fig. 6 shows in greater detail a heater element 301 according to various embodiments. The heater element 301 comprises an elongate housing 302 having an inner void 308 or cavity and a resistive heater element 350 located within the inner void 308 or cavity. The elongate housing 302 may be formed from a thermally conductive material such as aluminium or stainless steel. The elongate housing 302 may comprise a coating on its outer surface. The elongate housing 302 is configured to transfer heat from the resistive heater element 350 to an aerosol generating article. The elongate housing 302 has a base end 303 and a free end 304. The base end 303 may be attached to a heating chamber. A mount 305 may be provided at the base end 303 to secure the heater element 301. A groove 302a or region of reduced cross sectional diameter may be provided in the elongate housing 302 towards the base end 303 of the elongate housing 302. The groove 302a or region of reduced cross sectional diameter may act as a thermal break which reduces heat bleed from the heater element 301 into the mount 305 or more generally into a mounting point. The inner void 308 may be at least partially filled, for example, with a filler material.

The filler material may comprise one or more of: (i) a potting compound; (ii) an adhesive; (iii) a thermosetting plastic; or (iv) an epoxy resin. For example, the inner cavity may be at least partially filled with a thermally insulating material. The thermally insulating material may be a potting compound, an adhesive, a thermosetting plastic or an epoxy resin. The potting compound may comprise an epoxy resin. For example, a two-component epoxy may be used consisting of a polymer resin and a hardener which when mixed together causes a chemical reaction which cross-links chemical bonds in the polymer chains to create a tough, rigid and strong compound. The potting compound may alternatively comprise a polyurethane (“Pll”) e.g. a thermoset plastic. This may comprise a two-component compound consisting of a base resin with an isocyanate curing agent. Alternatively, the potting compound may comprise a silicone. For example, silicone rubber may be utilised comprising a synthetic polysiloxane polymer that uses an additive catalyser (such as platinum) to transition from a liquid to a solid state.

The heater element 311 has a tip 311 which extends to an apex 312. The resistive heater element 350 may comprise a heating coil 351. The heating coil 351 may comprise an electrically insulative coating, such as a ceramic, to electrically insulate the heating coil 351 from the elongate housing 302. Electrical connection paths may extend from each end of the heater element 350. A base electrical connection path 352 may extend from the distal end of the heater element 350. A return electrical connection path 353 may extend from the proximal end of the heater element 350. The heating coil 351 may be formed from a resistive material, such as a nickel/chrome alloy such as nichrome 80/20 (80% nickel, 20% chromium), an iron/chrome/aluminium alloy or a copper/nickel alloy.

Fig. 7A shows a standalone or one-piece aerosol provision device 400 according to an embodiment. An aerosol generating article 50 is shown partially inserted into a heating chamber of the aerosol provision device 400.

Fig. 7B shows a cross-sectional view of internal detail of the aerosol provision device 400 shown in Fig. 7A and shows a pin-shaped heater element 801 inserted into a distal end of a cylindrical aerosol generating article. As will be discussed in more detail below with reference to Figs. 14 and 15, the aerosol generating article may comprise a plurality of portions i.e. the aerosol generating article may comprise a first portion, a second portion and optionally a third portion. The aerosol generating article may comprise a fourth portion. The first portion may be positioned at a distal end of the aerosol generating article. The second and optional third and optional fourth portions may be located upstream from the first portion. According to various embodiments, the aerosol generating article may comprise a first (distal) portion, a second (intermediate) portion, a third (intermediate) portion and a fourth (proximal) portion. At least one of the second, third or fourth portions may include a filter. At least one of the second, third or fourth portions may include ventilation holes. At least one of the second, third or fourth portions may include frangible capsule which may be fragmented in order to introduce an additional flavourant or other agent into an aerosol generated in an aerosol generating portion of the aerosol generating article e.g. the first portion of the aerosol generating article. The fourth portion may comprise a mouth-end wherein a user may draw aerosol from the mouth-end. The pin-shaped heater element 301 is shown inserted into a first portion of the aerosol generating article. The first portion of the aerosol generating article may comprise aerosol generating material 801.

Fig. 8A illustrates a first computer aided design (“CAD”) model of a pin-shaped heater element 301 wherein the pin-shaped heater element 301 was modelled as being hollow and was modelled as having a coiled heater element 802 located within a cavity formed by the pin-shaped heater element 301. The pin-shaped heater element 301 was modelled as comprising a hollow body having a first cylindrical body portion and a tip portion. The coiled heater element 802 was modelled as being located within the cylindrical body portion of the pin-shaped heater element 301. The cylindrical body portion of the pin-shaped heater element 301 was modelled as having a wall thickness of 200 pm. The interior of the pin-shaped heater element 301 was modelled as being filled with a filter material. According to the first CAD model, the pin-shaped heater element 301 was modelled as being surrounded by a first cylindrical portion of an aerosol generating article.

Fig. 8B shows a simplified second CAD model which was utilised in various computational fluid dynamics (“CFD”) simulations. The second simplified second CAD model was modelled as comprising a consumable held in a consumable holder 803. The pin-shaped heater element 301 was modelled as comprising a coil heater element 802. A number of air inlets 805 were modelled as being provided in a base portion of the consumable holder 803.

It will understood that computational fluid dynamics (CFD) is a scientific simulation technique that is capable of providing spatially and temporally resolved predictions of complex physical problems involving the dynamics of a fluid. A preprocessing step may be performed wherein the geometry and the physical bounds of the problem may be defined using a model created by computer aided design (CAD). Once an initial CAD model has been created, data can then be suitably processed (i.e. cleaned-up) and fluid volume data (or fluid domain) can be extracted. The volume occupied by a fluid may be divided into discrete cells which may be referred to as a mesh. The mesh may be uniform or non-uniform. The mesh may be structured or unstructured. The mesh may comprise a combination of hexahedral, tetrahedral, prismatic, pyramidal or polyhedral elements. Physical modelling may then be defined e.g. various equations of fluid motion and other equations relating to e.g. heat flow may be input and various boundary conditions may be defined. The process of establishing boundary conditions may involve specifying the fluid behaviour and properties at all bounding surfaces of the fluid domain. For transient problems, initial conditions may also be defined. A simulation may then be commenced and the various physical modelling equations may be solved iteratively as a steady-state or transient. The simulation data may then be subjected to postprocessing in order to aid in the analysis and visualisation of the resulting solution.

Fig. 9 shows a heating profile which was set for the heater element modelled in Fig. 8B above and wherein a series of computational fluid dynamics (“CFD”) simulations were performed involving dynamic modelling of the heater element and consumable. The heater profile as shown in Fig. 9 and which was used in the CFD simulations had an overall session time of 300 s (i.e. 5 mins). The heating profile has modelled as having four progressive steps down in time during the course of a session of use whilst the temperature was maintained > 300 °C during the course of the session of use.

According to the model the heater element may be modelled as taking a few seconds to obtain the first desired target operating temperature (e.g. 350 °C). At the end of the simulation the heater element was modelled as assuming a temperature of 0 °C.

Time to may correspond with the time that the model assumes that the heater element is switched ON. According to the heating profile shown in Fig. 8 the heater element obtained a first operating temperature T1 for a time period tO-t1. The heater element is then modelled as being set a second lower operating temperature T2 for a time period t1-t2. The heater element is then modelled as being set a third lower operating temperature T3 for a time period t2-t3. Finally, the heater element is modelled as being set a fourth and final operating temperature T4 for a time period t3-t4. The total time period t0-t4 was modelled as being 300 s (5 mins). The heating profile as shown in Fig. 8 may be considered as comprising a base heating profile wherein the heater element is modelled as assuming a temperature > 300 °C throughout a simulated session of use.

It will be understood that although Fig. 9 shows a heating profile which was used for simulation purposes, an aerosol provision device according to various embodiments may be activated by a user at time to in order to cause a controller to set the heater element a desired heating profile. For example, a user may activate a user interface (see, for example, user interface 106 as shown in Fig. 1) provided on the aerosol provision device in order cause the heater element to follow a desired heating profile during a session of use. Once a user has interacted with the user interface and the controller has set a desired heating profile for the heater element there may be a short time delay before the heater element reaches a desired operating temperature and sufficient aerosol can be generated from an aerosol generating article at least partially inserted into the aerosol provision device. The time delay may be referred to as the ramp up time or time to first puff and may be approx. 10-20 s.

Fig. 10 illustrates how a pin-shaped heater element 301 was modelled in CAD in order to enable various CFD simulations to be performed. According to the CAD model, a coil heater element was modelled as being located within a pin-shaped heater element. The pin-shaped heater element was modelled as having a diameter Dp and a wall thickness T p. The length of the pin-shaped heater element was modelled as being Lp. The coil heater element was modelled as being displaced a distance Lh from a reference point. A cylindrical consumable portion was modelled as surrounding the pin-shaped heater element 301. The cylindrical consumable portion was modelled as having a length Lc and a diameter De.

Fig. 11 shows a table illustrating various parameters of the pin-shaped heater element as shown in the CAD model shown and described above with reference to Fig. 10. The table of parameters includes in the penultimate column minimum values of the parameters which were used in the various CFD simulations. The table of parameters also includes in the final column maximum values of the parameters which were used in the various CFD simulations. For example, in various CFD simulations which were performed the diameter of the pin-shaped heater element was varied in different CAD models which were used for the CFD simulations. For example, CFD simulations were run where the diameter of the pin-shaped heater element was modelled as being in the range 1.5-2.6 mm.

Fig. 12A shows an image from a CFD simulation of the pin-shaped heater element and consumable as were modelled with reference to the parameters shown in Figs. 10 and 11 and illustrates that an average volume temperature in the consumable Tvoi.avg.c may be determined from the CFD simulations.

Fig. 12B shows how the average volume temperature in the consumable Tvoi.avg.c was determined from CFD simulations to vary as a function of the ratio of the diameter of the consumable (De) to the diameter of the pin-shaped heater element (Dp) at a point in time corresponding to taking a tenth puff from the consumable.

Fig. 12C shows how the average volume temperature in the consumable T _vo i.avg.c was determined from CFD simulations to vary as a function of the ratio of the volume of the consumable (Vc) to the volume of the pin-shaped heater element (Vp) at a point in time corresponding to taking a tenth puff from the consumable.

Fig. 12D shows how the average volume temperature in the consumable T _vo i.avg.c was determined from CFD simulations to vary as a function of the ratio of the surface area of the consumable (Sc) to the surface area of the pin-shaped heater element (Sp) at a point in time corresponding to taking a tenth puff from the consumable.

Fig. 12E shows how the average volume temperature in the consumable T _vo i.avg.c was determined from CFD simulations to vary as a function of the ratio of the volume of the consumable (Vc) to the volume of the pin-shaped heater element (Vp, shell) at a point in time corresponding to taking a tenth puff from the consumable.

Fig. 13A shows an image from a CFD simulation of the pin-shaped heater element and consumable as were modelled with reference to the parameters shown in Figs. 10 and 11 and illustrates that an outer surface average temperature of the consumable Tsurf.avg.c may be determined from the CFD simulations.

Fig. 13B shows how the outer surface average temperature of the consumable Tsurf.avg.c was determined from CFD simulations to vary as a function of the ratio of the diameter of the consumable (De) to the diameter of the pin-shaped heater element (Dp) at a point in time corresponding to taking a tenth puff from the consumable.

Fig. 13C shows how the outer surface average temperature of the consumable Tsurf.avg.c was determined from CFD simulations to vary as a function of the ratio of the volume of the consumable (Vc) to the volume of the pin-shaped heater element (Vp) at a point in time corresponding to taking a tenth puff from the consumable.

Fig. 13D shows how the outer surface average temperature of the consumable Tsurf.avg.c was determined from CFD simulations to vary as a function of the ratio of the surface area of the consumable (Sc) to the surface area of the pin-shaped heater element (Sp) at a point in time corresponding to taking a tenth puff from the consumable.

Fig. 13E shows how the outer surface average temperature of the consumable Tsurf.avg.c was determined from CFD simulations to vary as a function of the ratio of the volume of the consumable (Vc) to the volume of the pin-shaped heater element (Vp, shell) at a point in time corresponding to taking a tenth puff from the consumable.

The CFD simulations which were performed established that a heater element having a surface area Sp and arranged to heat a consumable having a surface area Sc resulted in a desired volume average temperature T _vo i.avg.c of approx. 40 °C as shown and described above with reference to Figs. 12A and 12D when the ratio Sc/Sp was in the range 3.6-4.2. In particular, the CFD simulations which were performed have established that when a heater element having an outer diameter Dp, a volume Vp and an outer surface area Sp was modelled in a CAD design and wherein the CAD design modelled the heater element as being surrounded by a first cylindrical portion which was modelled as comprising aerosol generating material, wherein the first cylindrical portion had an outer diameter De, a volume Vc and an outer curved surface area Sc, then a ratio Sc/Sp in the range 3.6-4.2 was found to result in a desired volume average temperature Tvoi.avg.c of the consumable of approx. 40 °C after ten simulated puffs. Furthermore, the CFD simulations also established that if the ratio Sc/Sp were in the range 3.6-4.2 then this resulted in a desired outer surface average temperature Tsurf.avg.c of the consumable of approx. 75-85 °C after ten simulated puffs. Sp is the surface area of the heater element which faces the consumable. This includes the tip, the portion surrounding the heater coil and the portion leading up to the coil heater, as depicted in Fig. 10. Accordingly, the CFD simulations that were performed established that for a heater element having a surface area Sp which is used to heat a cylindrical consumable having a surface area Sc, then there is an optimum ratio of Sc/Sp which may be selected in order to result in a desired optimum performance in terms of the volume average temperature of the consumable and/or the outer surface average temperature of the consumable. In particular, the ratio Sc/Sp may be selected to be 3.6-4.2. According to various embodiments, the ratio Sc/Sp may be selected to be in the range 3.7-4.1 in order to result in a desired optimum performance in terms of the volume average temperature of the consumable and/or the outer surface average temperature of the consumable. According to further embodiments, the ratio Sc/Sp may be selected to be in the range 3.8-4.0 in order to result in a desired optimum performance in terms of the volume average temperature of the consumable and/or the outer surface average temperature of the consumable.

Related to the above and the optimum ratio Sc/Sp which may be selected to be in the range 3.6-4.2 in order to result in a desired optimum characteristic being generated in the consumable, other ratios have also been established as being particularly beneficial. For example, according to various embodiments (and as shown by Fig. 12C) the ratio Vc/Vp may be selected to be in the range 11.0-16.0 in order to result in a desired optimum performance. In particular, Vc/Vp may be selected to be in the range 12.0-15.0. According to other embodiments Vc/Vp may be selected to be in the range 13.0-14.0. Vp is the volume that the heater element occupies inside the consumable. In the simulations and other tests described herein, this includes the volume of the material of the heater element and the internal volume of the heater element, both covering the tip, the portion of the heater element surrounding the coil heater and the portion of the heater element leading up to the coil heater, as depicted in Fig. 10.

In a similar manner, in addition to the optimum ratio Sc/Sp which may be selected being in the range 3.6-4.2, according to various embodiments (and as shown by Fig. 12B) the ratio Dc/Dp may be selected to be in the range 3.1-3.6 in order to result in a desired optimum performance. In particular, Dc/Dp may be selected to be in the range 3.2-3.5. According to other embodiments Dc/Dp may be selected to be in the range 3.3- 3.4.

In a similar manner, the CFD simulations that were performed established that for a heater element having a volume Vp, shell which is used to heat a cylindrical consumable having a volume Vc, then there is an optimum ratio of Vc/Vp, shell which may be selected in order to result in a desired optimum performance in terms of the volume average temperature of the consumable (shown in Fig. 12E) and/or the outer surface average temperature of the consumable (shown in Fig. 13E). In particular, the ratio Vc/Vp, shell may be selected to be at least 31.0. According to various embodiments, the ratio Vc/Vp, shell may be selected to be in the range 31.0-131.0 in order to result in a desired optimum performance in terms of the volume average temperature of the consumable and/or the outer surface average temperature of the consumable. According to further embodiments, the ratio Vc/Vp, shell may be selected to be in the range 81.0-131.0 in order to result in a desired optimum performance in terms of the volume average temperature of the consumable and/or the outer surface average temperature of the consumable. In further embodiments, the ratio Vc/Vp, shell may be selected to be in the range 101.0-131.0 in order to result in a desired optimum performance in terms of the volume average temperature of the consumable and/or the outer surface average temperature of the consumable.

The volume Vp, shell of the heater element is the volume of an outer shell of the heater element, and does not include the volume of the cavity defined by the outer shell. In the simulations and other tests described herein, this includes the volume of the entire outer shell, including the tip of the outer shell. With reference to Figure 8A, the heater element 301 may comprise a heater element 802 arranged within an outer shell 807. As such, the volume Vp may be the volume defined by the material forming the outer shell 807.

An aerosol provision device having a heater element with surface area Sp was tested with a consumable having a surface area Sc, wherein Sc/Sp =3.9, as indicated by the dashed lines on Fig. 12D and Fig. 13D. Accordingly, an aerosol provision device was tested wherein the ratio Sc/Sp was in the range 3.6-4.2. A heating profile as shown in Fig. 9 was applied to the heating element. An initial assessment on sensory attributes such as visible aerosol generation, the feeling on the mouth, the sensation at the back of the throat (i.e. impact), taste quality and whether or not there any off notes were detected was made. The initial assessment confirmed that a positive sensory experience resulted.

An aerosol provision device having a heater element with surface area Sp was then subjected to further more detailed testing with a consumable having surface area Sc, wherein Sc/Sp = 3.9. Further parameters of the aerosol provision device subjected to the testing and the more detailed testing are defined in the highlighted first data column of Fig. 11 (i.e. with Tp = 0.2 mm, Dp = 2.15 mm, De = 7.23 mm, Lp = 11 mm, Lc = 12 mm and Lh = 2 mm, giving Dc/Dp = 3.4 and Vc/Vp = 13.5, as indicated by the dashed lines on Fig. 12B, Fig. 12C, Fig. 13B and Fig. 13C). In the more detailed testing, the aerosol provision device was tested by a panel of 6-10 users and the sensory experience was assessed using a sequential monadic testing methodology involving taking 10 puffs during the course of a session. It was found to result in an excellent overall sensory experience. In particular, sixteen different sensory attributes were assessed. Six of the sensory attributes related to “immediacy” and were assessed after the first two puffs in a session. These sensory attributes were draw resistance, aerosol warmth, visible aerosol, impact, irritation and flavour amplitude. A further ten sensory attributes relating to “overall experience” were assessed after taking 10 puffs during the course of a session of use. These attributes were draw resistance, aerosol warmth, visible aerosol, impact, irritation, tobacco taste intensity, flavour amplitude, overall flavour intensity, off taste and flavour consistency. The sensory testing confirmed that an aerosol provision device having a heater element with a surface area Sp when used with a consumable having a surface area Sc resulted in an excellent sensory experience when the ratio Sc/Sp was arranged to be in the range 3.6-4.2.

It has also been found that an aerosol provision device having a heater element with a surface area Sp when used with a consumable having a surface area Sc, and wherein the ratio Sc/Sp was arranged to be in the range 3.6-4.2 was found not to result in undesirable hot puffs. Furthermore, the temperature of the aerosol provision device in the hand of the user was also found to be within acceptable safety limits. A yet further benefit of utilising an aerosol provision device having a heater element with a surface area Sp when used with a consumable having a surface area Sc, and wherein the ratio Sc/Sp is in the range 3.6-4.2 is that the generation of undesirable condensate is substantially avoided.

According to various embodiments an aerosol provision device having a heater element with a surface area Sp when used with a consumable having a surface area Sc, and wherein the ratio Sc/Sp is arranged to be in the range 3.6-4.2 may be provided wherein after a ramp time t_start and/or when the heater element has reached a first target operating temperature T 1 , one or more indicator devices may indicate to the user that the aerosol provision device is ready for use. For example, the indicator device may comprise one or more light emitting diodes (LEDs) provided on a user interface of the aerosol provision device. The number of LEDs illuminated and/or the colour of one or illuminated LEDs and/or the intensity of one or more illuminated LEDs may indicate to a user when the aerosol provision device is ready for use. Additionally or alternatively, the indicator device may comprise a haptic feedback device. Embodiments are also contemplated wherein the indicator device may additionally or alternatively comprise an audible indicator device. One or more indicator devices as described above may also indicate to a user when an aerosol generation session has been completed.

As will be discussed in more detail below with reference to Fig. 14, embodiments are contemplated wherein the aerosol provision device may be utilised in conjunction with an aerosol generating article having a flavour capsule. The aerosol provision device may be operated in either a first or base heating mode of operation or in a second or boost heating mode of operation. The first heating mode of operation may provide an optimum sensory experience when the flavour capsule is not fragmented and the second heating mode of operation may provide an optimum sensory experience when the flavour capsule is fragmented. Other embodiments are contemplated wherein the first heating mode may provide an optimum sensory experience when the flavour capsule is fragmented and the second heating mode may provide an optimum sensory experience when the flavour capsule is not fragmented.

According to embodiments the aerosol provision device may comprise a first heater element and a second heater element. The first heater element may be provided so as to form a first heating zone which is arranged to heat a portion of an aerosol generating article and the second heater element may be provided so as to form a second heating zone which is arranged to heat a different portion of the aerosol generating article.

According to various embodiments an aerosol provision device is provided comprising a controller. The controller may be arranged to set a heating profile for the heater element which may comprise a pin-shaped heater element (or a blade-shaped heater element). The heater element is configured to heat an aerosol generating article comprising a plurality of different sections or portions. The aerosol generating article may, in particular, comprise a cylindrical article comprising e.g. a cylindrical portion of aerosol generating material provided in a distal portion of the article. The cylindrical portion of aerosol generating material may have a diameter of approx. 7.0 mm and a length of 12.0 mm. Upstream of the cylindrical portion of aerosol generating material may be provided a first tubular element having a length of about 7 mm and an outer diameter of approx. 7.0 mm. Upstream of the first tubular element a second tubular element may be provided having a length of about 17 mm and an outer diameter of approx. 7 mm. The cylindrical portion of aerosol generating material, the first tubular element and the second tubular element may be wrapped in one or more outer wrappings which may have a total thickness of approx. 200 pm.

Fig. 14 shows a side-on cross sectional view of an aerosol generating article 1001 which may be utilised with an aerosol provision device 1003 comprising, for example, a pin-shaped heater element 1002a as discussed in more detail above according to various embodiments. The pin-shaped heater element 1002a may be controlled by a controller (not shown) and according to various embodiments a heating profile such as a heating profile as shown and described above in relation to Fig. 9 may be set for the heater element 1002a. In particular, the heater element 1002a may be operated in a first or base mode of operation so that a heating profile as shown in Fig. 9 may be set for the pin-shaped heater element 1002a according to an embodiment. As discussed above, the heating profile may have a profile comprising a series of four steps down during the course of a session of use. The temperature set for the heater element 1002a may be maintained > 300 °C throughout a session of use. According to other embodiments the heater element 1002a may be operated in a second or boost mode of operation so that a different heating profile may be set for the pin-shaped heater element 1002a. As discussed above, the heating profile may have a profile comprising a series of four steps down during the course of a session of use. The temperature set for the heater element 1002a may be maintained > 300 °C throughout a session of use. It is noted that whereas a first or base mode of operation may enable a user to experience an aerosol generation session which lasts for approx. 300 s after the initial time to first puff (t_start), a second or base mode of operation may enable a user to experience a different sensory experience wherein an aerosol generation session lasts for a shorter period of time e.g. 180 s after the initial time to first puff (t_start). The different sensory experience may in part be achieved by ensuring that the average temperature set for the heater element 1002a during the second or boost mode of operation is higher than the average temperature set for the heater element 1002a during the first or base mode of operation.

According to various embodiments the aerosol provision device 1003 may more generally comprise a heater element having an outer diameter Dp, a volume Vp and an outer surface area Sp. The heater element may be configured to be inserted into an article 1001 , wherein the article 1001 comprises a first cylindrical portion comprising aerosol generating material. The first cylindrical portion has an outer diameter De, a volume Vc and an outer curved surface area Sc. The heater element may be arranged to have a surface area such that Sc/Sp is in the range 3.6-4.2.

The aerosol generating article 1001 may comprise an aerosol generating section 1004 which in use may be inserted into a receiving portion 1002 of an aerosol provision device 1003. The receiving portion 1002 may comprise a recess in the aerosol provision device 1003. The aerosol provision device 1003 may comprise a heater element such as a pin-shaped heater 1002a. The pin-shaped heater 1002a may be located within the receiving portion 1002 of the aerosol provision device 1003 and the pin-shaped heater may be arranged to penetrate the aerosol generating section 1004 of the aerosol generating article 1001 as the aerosol generating article 1001 is inserted, in use, into the aerosol provision device 1003. The pin-shaped heater 1002a may be resistively heated and may comprise a resistive heater element. However, alternative embodiments are contemplated wherein the heater element 1002a may comprise a blade-shaped heater element. Further embodiments are contemplated wherein the heater element may comprise a heater element formed of a heating material which may be inductively heated and may comprise a susceptor element. A magnetic field generator may be provided which is arranged to induce an alternating electric current in the susceptor element thereby causing heating of the susceptor element. The article 1001 may comprise a downstream section 1005 downstream of the aerosol generating section 1004. The downstream section 1005 may comprise or may include a mouthpiece designed to be inserted into a user’s mouth in use. The downstream section 1005 may comprise an upstream end 1005a and a downstream end 1005b. The aerosol generating section 1004 may comprise a source of aerosol generating material in the form of a cylindrical rod of aerosol generating material. In other examples, the aerosol generating section 1004 may comprise a cavity for receiving a source of aerosol generating material. The aerosol generating material may include at least 5% of an aerosol-former material by weight of the aerosol generating material, calculated on a dry weight basis. The aerosol aerosol-former material may, for example, comprise glycerol or propylene glycol.

The mouthpiece or downstream portion 1005 may include a first tubular element 1008a arranged immediately downstream of the aerosol generating section 1004. The first tubular element 1008a may define a first hollow cavity. The first tubular element 1008a may be in an abutting relationship with the aerosol generating section 1004. The first tubular element 1008a may have a first tubular wall. The mouthpiece or downstream portion 1005 may also include a second tubular element 1008b immediately downstream of the first tubular element 1008a. The second tubular element 1008b may be in an abutting relationship with the first tubular element 1008a. The second tubular element 1008b may have a second tubular wall having a wall thickness of less than about 320 pm. The second tubular element 1008b may have an axial length of 15-25 mm, for example 17 mm. A body of material 1006 may be provided at the downstream end 1005b of the downstream section 1005. The first and second tubular elements 1008a, 1008b and the body of material 1006 may each define a cylindrical outer shape and may be arranged end-to-end on a common axis. The first and second tubular elements 1008a, 1008b, the aerosol generating section 1004 and the body of material 1006 may be arranged to have approximately the same outer diameter.

The first and second tubular elements 1008a, 1008b together may define a chamber into which aerosol formed in the aerosol generating section 1004 is drawn and expands and cools. The provision of discrete first and second tubular elements 1008a, 1008b enables these components to be designed to achieve different functional effects. For instance, the first tubular element 1008a may be effective in reducing movement of the aerosol generating material when the article 1001 is inserted into the recess 1002 and on to the pin-shaped heater element 1002a. For this purpose, the first tubular element 1008a may have a wall thickness of 1.0-3.5 mm e.g. 1.5-2.5 mm. The first tubular element 1008a may assist with providing rigidity to the article 1001. The first tubular element 1008a may also be arranged to encourage aerosol to flow predominantly through an axial region of the second tubular element 1008b in order to assist with aerosol formation. By contrast, the second tubular element 1008b may be arranged to define a relatively large chamber as compared to the first tubular element 1008a thereby providing a greater space into which the aerosol formed in the aerosol generating section 1004 can be drawn into so that the aerosol expands and cools.

The aerosol generating article 1001 may have a circumference of 22.1 mm corresponding to a diameter of 7.0 mm. The aerosol generating section 1004 may have a length of 12.0 mm, the first tubular element 1008a may have a length of 7.0 mm and the second tubular element may have a length of 17.0 mm. According to various embodiments aerosol generating material provided in the aerosol generating section 1004 may comprise a plurality of strands or strips of aerosol generating material. The strands or strips of aerosol generating material may be arranged such that their longitudinal dimension is substantially parallel with the longitudinal axis of the aerosol generating article 1003. The aerosol generating material may be in the form of reconstituted sheet tobacco material, such as bandcast reconstituted tobacco. The wall of the second tubular element 1008b may comprise first and second overlapping paper layers each extending around substantially the whole circumference of the second tubular element 1008b. The first and second overlapping paper layers may each have a thickness of 30-150 pm. The aerosol provision device 1003 may comprise a housing 1009 and an aperture 1010 in the housing 1009 into which the article 1001 may be inserted in use. When the article 1001 is fully inserted into the aerosol provision device 1003, the second tubular element 1008b may extends at least about 5 mm within and at least 8 mm beyond the housing 1009. The article 1001 may be inserted into the aerosol provision device 1003 to an insertion depth of about 25 mm, as shown by arrow ‘B’ in Fig. 14.

It will be understood by those skilled in the art that bandcast reconstituted tobacco has a relatively high density. It is noted that the heating profile as disclosed above with reference to Fig. 9 has a relatively high maximum target operating temperature of e.g. 350 °C and also a relatively high minimum target operating temperature of e.g. 300 °C. Over the course of a session of use, a heating profile such as the one discussed above with reference to Fig. 9 may have an average target operating temperature > 300 °C. The relatively high target operating temperatures are particularly suitable for generating aerosol from an article comprising bandcast reconstituted tobacco.

The article 1001 may comprise one or more ventilation apertures 1012 extending through the second tubular element 1008b at a location in the second tubular element 1008b which is outside the housing 1009 when the article 1001 is fully inserted into the aerosol provision device 1003. The one or more ventilation apertures 1012 may be provided as one or more rows of apertures, such as laser or mechanically formed perforations, circumscribing the article 1001. The cylindrical rod of aerosol generating material may comprise a plurality of strands and/or strips of aerosol generating material which are circumscribed by a wrapper 1015. The wrapper 1015 may be a moisture impermeable wrapper. The plurality of strands or strips of aerosol generating material may be aligned within the aerosol generating section 1004 such that their longitudinal dimension is in parallel alignment with the longitudinal axis, X-X’ of the article 1001. Alternatively, the strands or strips may generally be arranged such that their longitudinal dimension aligned is transverse to the longitudinal axis of the article 1001. Where the majority of the strands or strips are arranged in the aerosol generating section 1004 such that their longitudinal axis is parallel with the longitudinal axis of the aerosol generating section 1004 of the article 1001 , the force required to insert an heater element, such as a heater element 1002a into the aerosol generating material may be relatively low. This can result in an article 1001 which is easier to use.

The rod of aerosol generating material may have a circumference of about 22.1 mm (corresponding to a diameter of 7.0 mm). The first tubular element 1008a may be formed from filamentary tow such as plasticised cellulose acetate tow. The wall of the first tubular element 1008a may be relatively non-porous, such that at least 80% of the aerosol generated by the aerosol generating material passes longitudinally through the hollow channels through the tube rather than through the wall material itself. The first and second tubular elements 1008a, 1008b may be configured to provide a temperature differential of at least 40 °C between a heated volatilised component entering a first upstream end of the first and second tubular elements 1008a, 1008b and a heated volatilised component exiting a second downstream end of the first and second tubular elements 1008a, 1008b. This temperature differential across the length of the first and second tubular elements 1008a, 1008b may protect a temperature sensitive body of material 1006 from the high temperatures of the aerosol generating material when it is heated.

The moisture impermeable wrapper 1015 which circumscribes the rod of aerosol generating material may comprise aluminium foil. The body of material 1006 may be wrapped in a first plug wrap 1007. A second plug wrap 1013 may be provided to connect the body of material 1006, the first tubular element 1008a and second tubular element 1008b. The length of the body of material 1006 may be less than about 15 mm e.g. 12 mm. The body of material 1006 may be formed from filamentary tow. For example, the tow may comprise plasticised cellulose acetate tow or polylactic acid (PLA).

As shown in Fig. 15 a tipping paper 1016 may be wrapped around the full length of the downstream portion 1005 and over part of the rod of aerosol generating material. The tipping paper 1016 may have an adhesive on its inner surface to connect the downstream portion 1005 and the rod of aerosol generating material. The rod of aerosol generating material may be wrapped in a wrapper 1015, which forms a first wrapping material, and the tipping paper 1016 may form an outer wrapping material which extends at least partially over the rod of aerosol generating material to connect the downstream portion 1005 and the rod of aerosol generating material. The tipping paper 1016 may extend 5 mm over the rod of aerosol generating material to provide a secure attachment. The article 1001 may have a ventilation level of about 25% of the aerosol drawn through the article 1001. The article 1001 may include ventilation apertures provided into the second tubular element 1008b. A second hollow cavity defined by the second tubular element 1008b may have a diameter of about 6.6 mm and a radius ‘r’ as shown in Fig. 11 of about 3.3 mm.

An aerosol modifying agent may be provided within the body of material 1006 in the form of an additive release component. As shown in Fig. 14, the additive release component may comprise a capsule 1011. However, it should be understood that the capsule 1011 is optional and may be omitted according to various embodiments. If the article 1003 comprises a capsule 1011 then the first plug wrap 1007 may comprise an oil-resistant first plug wrap 1007. The capsule 1011 may comprise a breakable capsule i.e. a solid frangible shell surrounding a liquid payload. The capsule 11 may comprise a shell encapsulating a liquid agent such as a flavourant or other agent. The shell of the capsule may be ruptured by a user to release the flavourant or other agent into the body of material 1006. The capsule 1011 may be spherical and may have a diameter of about 3 mm. The aerosol generating material may comprise an aerosol-former material. The aerosol-former material may comprise, for example, glycerol or propylene glycol. The aerosol generating material may comprise an aerosol modifying agent such as menthol.

The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and/or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc, other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.