Apparatus for Heating Smokeable Material

Abstract

An apparatus is configured to heat smokeable material to volatilize at least one component of the smokeable material. The apparatus comprises a heater comprising a carbonisable electrical insulating material. The heater is arranged to carbonise the insulating material to cause progressive heating of the smokeable material.

Description

TECHNICAL FIELD

The present invention relates to apparatus for heating smokeable material.

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 that burn tobacco by creating products that release compounds without burning. Examples of such products are so-called heat-not-burn products which release compounds by heating, but not burning, the material. The material may be for example tobacco or other non-tobacco products, which may or may not contain nicotine.

SUMMARY

According to the present invention, there is provided an apparatus configured to heat smokeable material to volatilize at least one component of the smokeable material, wherein the apparatus comprises a heater comprising a carbonisable electrical insulating material, and wherein the heater is arranged to carbonise the insulating material to cause progressive heating of the smokeable material.

In use, the carbonisation of the electrical insulating material supplies heat to the smokeable material to volatilize at least one component of the material.

The heater may be configured to trigger carbonisation of the electrical insulating material.

The heater may be configured to trigger carbonisation of the electrical insulating material in response to a user action.

The heater may be configured to trigger carbonisation of the electrical insulating material by heating the electrical insulating material to a carbonisation temperature of the electrical insulating material.

The heater may comprise a heating element arranged to trigger carbonisation of the electrical insulating material by heating the electrical insulating material to the carbonisation temperature.

The heating element may be in contact with a first end of the electrical insulating material.

The heating element may traverse the electrical insulating material. Thus, the heating element may extend from one side or one end of the electrical insulating material to the other. The heating element may be positioned substantially on a surface of the electrical insulating material, and may extend across the surface. Alternatively, the heating element may to some extent be encompassed by the electrical insulating material. For example, the heating element may extend through a portion of the electrical insulating material.

The apparatus may be configured to trigger carbonisation of the electrical insulating material by causing an electrical current to pass through the heating element.

The heating element may be resistively heated by the electrical current to the carbonisation temperature of the electrical insulating material.

The heater may comprise a plurality of electrodes, which may be separated and electrically isolated by the electrical insulating material. The plurality of electrodes comprises at least one electrode of each polarity. In particular, the plurality of electrodes may comprise two electrodes, one of each polarity, or a plurality of pairs of electrodes in which each pair comprises one electrode of each polarity. Alternatively, the plurality of electrodes may comprise a plurality of electrodes of a first polarity paired with a single electrode of a second polarity, or a single electrode of the first polarity paired with a plurality of electrodes of the second polarity.

The electrodes may extend from a first end of the heater to a second end of the heater. Electrodes of opposite polarity may be separated from one another along their entire length by the electrical insulating material.

The apparatus may be configured to trigger carbonisation of the electrical insulating material by causing a current to pass between electrodes of opposite polarity.

The heating element may be connected between electrodes of opposite polarity.

The heater may be arranged such that in use, the electrical insulating material is carbonised at the first end of the heater when a current is passed between electrodes of opposite polarity. The carbonisation temperature of the electrical insulating material may be more than 100° C., such as more than 120° C. or more than 150° C. The carbonisation temperature may, for example, be between 150° C. and 250° C., such as approximately 170° C.

The heating element may comprise a sacrificial overload device which heats the electrical insulating material to the carbonisation temperature in response to a predetermined electrical current through the device.

The electrodes of opposite polarity may be coupled at a first end of the heater by the sacrificial overload device, such as a length of fuse wire. The sacrificial overload device may be arranged such that when supplied with a predetermined electrical current, the sacrificial overload device overheats to a temperature exceeding the carbonisation temperature of the electrical insulating material.

The electrical insulating material may be pre-carbonised, for example at a first end of the heater, to provide an electrically conductive bridge between electrodes of opposite polarity.

The electrical insulating material may be configured to carbonise progressively from a first end to a second end in response to carbonisation being initially triggered by the heating element. The progressive carbonisation of the electrical insulating material may occur without further heating by the heating element.

Progressive carbonisation of the electrical insulating material may cause corresponding progressive heating of the smokeable material. The progression may cause consecutive heating of previously unheated sections of smokeable material over the progressive carbonisation period of the electrical insulating material.

Progressive carbonisation of the electrical insulating material may be caused by an electrical arc which progresses from a first end of the electrical insulating material to a second end of the electrical insulating material.

The electrical arc may extend between electrodes of opposite polarity across the electrical insulating material.

The heater may be arranged such that in use, a current passing between electrodes of opposite polarity causes carbonisation of the electrical insulating material to occur progressively from the first end of the heater to the second end. For example, the rate of migration may be such that the smokeable material is progressively heated by the progressive carbonisation of the electrical insulating material over a period of between approximately 4 and 8 minutes.

In use, the heater may provide a region of elevated temperature (a “heating zone”), and this region may be small in comparison to the total surface area of the heater. For example, the region of elevated temperature may comprise less than 10%, less than 20%, or less than 40% of the total surface area of the heater.

The region of elevated temperature may migrate progressively from a first end of the heater to its second end to progressively heat the smokeable material.

The heater may be positioned in a cavity within a charge of smokeable material, for example, within an annular charge of smokeable material.

The heater may be positioned around a periphery of a charge of smokeable material, which may be a cylindrical charge of smokeable material.

The heater may be enclosed within a gas impermeable container.

The gas impermeable container may be thermally conductive.

The thermal conductivity of the gas impermeable container may be greater in a lateral dimension than in a longitudinal dimension. This may aid the formation of a lateral heating band around the container, which progresses along the container as the electrical insulating material progressively carbonises.

The gas impermeable container may include a vent, which may comprise a one-way valve, to allow any gases produced by the heater to escape from the container. The vent may not be in fluid communication with the smokeable material.

The electrical insulating material may be a cellulosic or fibrous material, or a resin. The electrical insulating material may comprise a paper material.

The apparatus may be configured to heat the smokeable material without combusting the smokeable material.

In use, the carbonisation of the electrical insulating material supplies heat to the smokeable material.

BRIEF DESCRIPTION OF THE FIGURES

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

FIG. 1 is a perspective, partially cut-away illustration of an example of an apparatus configured to heat smokeable material, according to a first embodiment;

FIG. 2 is an exploded, partially cut-away view of the apparatus of FIG. 1;

FIG. 3 is a perspective view of an example of a heater in the apparatus shown in FIG. 1;

FIG. 4A is a transverse cross-sectional view of an example of a heater and smokeable material in the apparatus shown in FIG. 1;

FIG. 4B is a transverse cross-sectional view of an example of heaters and smokeable material of a second embodiment of the invention, comprising two heaters;

FIG. 4C is a transverse cross-sectional view of an example of heaters and smokeable material of a third embodiment of the invention, comprising three heaters;

FIG. 5A is a transverse cross-sectional view of an example of a heater of a fourth embodiment of the invention;

FIG. 5B is a transverse cross-sectional view of an example of a heater of a fifth embodiment of the invention;

FIG. 6A is a transverse cross-sectional view of an example of a heater of a seventh embodiment of the invention;

FIG. 6B is a transverse cross-sectional view of an example of a heater of an eighth embodiment of the invention; and

FIG. 6C is a transverse cross-sectional view of an example of a heater of a ninth embodiment of the invention.

DETAILED DESCRIPTION

As used herein, the term “smokable material” includes materials that provide volatilized components upon heating, typically in the form of an aerosol. “Smokable material” includes any tobacco-containing material and may, for example, include one or more of tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes. “Smokable material” also may include other, non-tobacco, products, which, depending on the product, may or may not contain nicotine.

FIG. 1 shows an example of an apparatus for heating smokeable material according to a first embodiment.

As shown in FIG. 1, the apparatus 1 comprises an energy source 2, a heater 3, and a heating chamber 4 which contains smokeable material 5.

The energy source 2 of this example comprises a Li-ion battery. Any suitable type of energy source, such as a Ni battery, alkaline battery and/or the like, may alternatively be used. The energy source 2 may be rechargeable. The energy source 2 is electrically coupled to the heater 3 to supply electrical energy to the heater 3 in use.

The heating chamber 4 is configured to receive smokeable material 5 so that the smokeable material 5 can be heated in the heating chamber 4. The heater 3 and heating chamber 4 are arranged so that the heater 3 is able to heat the heating chamber 4. Generally, and in the embodiment shown in FIG. 1, the heating chamber 4 is located adjacent to the heater 3 so that thermal energy from the heater 3 heats the smokeable material 5 in the heating chamber 4. The heater 3 is configured to heat the heating chamber 4 sufficiently to volatilize aromatic compounds and nicotine in the smokeable material 5 without burning the smokeable material 5.

In the embodiment shown in FIG. 1, the heater 3 is in the form of a substantially cylindrical, elongate rod, which extends along part of a central longitudinal axis of the apparatus 1, towards the mouth end. The heating chamber 4 is located around the circumferential, longitudinal surface of the heater 3. The smokeable material 5 is in the form of a hollow, annular cylinder which fits within the heating chamber 4. The smokeable material 5 is located within the apparatus 1 such that the heater 3 is positioned within the central longitudinal cavity of the smokeable material 5. The smokeable material 5 thus fits closely around the heater 3 to ensure efficient heat transfer from the heater 3 to the smokeable material 5. The heating chamber 4 and smokeable material 5 therefore comprise co-axial layers around the heater 3. However, as will be evident from the discussion below, in other embodiments, other shapes and configurations of the heater 3, heating chamber 4, and smokeable material 5 can alternatively be used.

As outlined above, the smokeable material 5 may comprise tobacco, for example in the form of a tobacco blend, or some other volatisable material.

FIG. 2 is an exploded diagram of the apparatus shown in FIG. 1. As shown in FIG. 2, the apparatus 1 further comprises an annular mouthpiece 6 and a housing 7 in which the components of the apparatus 1 such as the energy source 2 and heater 3 are contained.

In the embodiment shown, the housing 7 comprises an approximately cylindrical tube with the energy source 2 located towards its first end 8, and the heater 3 and heating chamber 4 located towards its opposite, second end 9. As shown in FIG. 1, the energy source 2 and heater 3 are aligned along the central longitudinal axis of the housing 7.

The mouthpiece 6 attaches to the second end 9 of the housing 7, which may also be considered to be the mouth end of the apparatus 1. The mouthpiece 6 is located adjacent to the heating chamber 4 and smokeable material 5, such that the annular mouthpiece 6 provides a passageway 10 for fluid communication between the mouth of the user and the heating chamber 4.

Thermal insulation 11 is provided between the smokeable material 5 and the housing 7 to reduce heat loss from the apparatus 1 and therefore improve the efficiency with which the smokeable material 5 is heated. For example, a layer of thermal insulation 11, comprising a substantially tubular length of thermal insulation 11, may be located co-axially around the heating chamber 4 and smokeable material 5.

As shown in FIG. 2, the layer of thermal insulation 11 in this example comprises vacuum insulation, and in particular in this example comprises a double-wall arrangement 12 enclosing an internal region 13. An example of a suitable material for the double wall arrangement 12 is stainless steel and an example of a suitable thickness for the walls of the double wall arrangement 12 is approximately 100 μm. The internal region or core 13 of the insulation 11 comprises a void. In other embodiments, the internal region 13 may include open-cell porous materials comprising, for example, polymers, aerogels or other suitable materials, which may be evacuated to a low pressure. The pressure in the internal region 13 is generally in the range of 0.1 to 0.001 mbar. The thermal conductivity of the thermal insulation 11 is generally in the range of 0.004 to 0.005 W/mK.

A reflective coating may be applied to the internal surfaces of the double wall arrangement 12 to further reduce heat losses through the thermal insulation 11. The coating may, for example, comprise an aluminium infrared (IR) reflective coating.

The apparatus 1 comprises air conduits 14, which allow external air to be drawn into the housing 7 and through the heating chamber 4 when the apparatus 1 is in use. The air conduits 14 comprise apertures 14 in the housing 7 which are located upstream from the smokeable material 5 and heating chamber 4 towards the first end 8 of the housing 7. The air conduits 14 may also allow any excess heat from the energy source 2 to be dissipated.

The heating chamber 4 comprises inlet valves 15 which, when closed, prevent gaseous flow from the air conduits 14 into the heating chamber 4. The valves 15 thereby reduce the diffusion of air and smokeable material flavours from the heating chamber 4, as discussed in more detail below. The valves 15 may be located within a cylindrical buffer 16 which is positioned at the end of the heating chamber 4 towards the first end 8 of the housing 7. More specifically, the cylindrical buffer 16 may be positioned to separate the energy source 2 and air conduits 14 on one side, from the heater 3, heating chamber 4, and smokeable material 5 on the other side of the cylindrical buffer 16. The buffer 16 thereby provides heat insulation between the energy source 2 and the heater 3 to prevent direct transfer of heat from one to the other. The buffer 16 also comprises an arrangement (not shown) for electrically coupling the heater 3 to the energy source 2.

An example of the heater 3 is shown in detail in FIG. 3. The heater 3 comprises a heater assembly 17 enclosed within a container 18. The heater assembly 17 comprises first and second electrodes 19, 20, and these electrodes 19, 20 are separated and electrically isolated from one another by an electrical insulating material 21.

The container 18 is thermally conductive to allow heat generated by the heater assembly 17 to be efficiently transmitted to the heating chamber 4. The container 18 is not gas permeable and any gases that may be produced by the heater assembly 17 cannot pass through the container 18, for example to enter the heating chamber 4. The container 18 may in some embodiments comprise a vent or one-way valve to allow any gases produced by the heater assembly 17 to escape from the container. However, the vent is generally not in fluid communication with the smokeable material 5 or mouthpiece 6 so that any gases emitted by the heater assembly 17 cannot dilute the aromatic compounds and nicotine released from the smokeable material 5, and cannot be inhaled by the user.

In general, the container 18 may be composed of any gas impermeable, thermally stable, and thermally conductive material. In the embodiment shown in FIG. 3, the container 18 comprises aluminium. Other suitable materials include plastics, metals, glass, and ceramics. While the container 18 should be thermally conductive to allow efficient heat transfer to the heating chamber 4, it may be configured such that thermal conduction along the length of the container 18 is minimised to ensure that only a small section of the outer circumferential surface of the heater 3 is at an elevated temperature at any given time. The small section of elevated temperature may comprise, for example a circumferential band around the container 18. To minimise the effect of thermal conduction longitudinally along the heater 3, in the embodiment shown in FIG. 3, the container 18 comprises a plurality of individual panels of thermally conductive material, such as aluminium 22. The panels 22 are thermally separated from one another to substantially prevent the panels 22 from heating each other. For example, the panels 22 may be bonded together using a thermally insulating bonding agent. Other arrangements may be used in other embodiments. In general, any suitable arrangement may be used which permits the efficient conduction of thermal energy from the inside to the outside of the heater 3, but inhibits or reduces the conduction of thermal energy longitudinally along the length of the heater 3. For example, instead of comprising individual panels, the container 18 may comprise a thermally conductive material that is coiled or wound around the heater assembly 17 to form the container 18.

The first and second electrodes 19, 20 comprise rods of electrically conductive material, such as copper, which extend from one end of the heater to the other. The rods may be approximately 0.5 mm in diameter.

Between the first and second electrodes 19, 20 is an electrical insulating material 21. The electrical insulating material 21 electrically isolates the first and second electrodes 19, 20. In addition, the electrical insulating material 21 is capable of being carbonised. In the embodiment shown in FIG. 3, the electrical insulating material 21 comprises a paper material which is in close contact with both the first and second electrodes 19, 20.

The first and second electrodes 19, 20 are electrically coupled to the energy source 2. The electrical coupling between one or both of the electrodes 19, 20 and the energy source 2 is controlled by means of a switch (not shown), which may be user-operable. For example, the switch may comprise a push-button or similar at the exterior of the apparatus 1 or may be puff-activated. At one end of the heater assembly 17 the first electrode 19 is connected to the second electrode 20 by a heating element 23, which is described in further detail below. The heating element 23 is also in contact with the electrical insulating material 21. The heating element 23 is configured to trigger progressive carbonisation of the electrical insulating material 21 by heating an initial section of the electrical insulating material 21 to a carbonisation temperature. For example, the heating element 23 may be configured to initiate an electrical arc between electrodes 19, 20 across the electrical insulating material 21. The electrical arc may cause the electrical insulating material 21 to progressively carbonise as the arc progresses from one end of the heater assembly 17 to the other. The heating element 23 may be any material or device that heats to a temperature exceeding the carbonisation temperature of the electrical insulating material 21, such as between about 200° C. and 350° C. For example, the heating element 23 may be a fuse wire, and may overheat to this temperature when carrying a particular value of electrical current. The heating element 23 may be destroyed in the process of heating the insulating material 21 to the carbonisation temperature. For example, when the heating element 23 is a fuse wire, the heating element 23 may melt. Alternatively, the heating element 23 may not be destroyed. The electrical current is supplied to the heating element 23 by the energy source 2. Other suitable materials for the heating element 23 may, for example, include carbon-containing materials such as a carbon paste.

The heater 3 is activated by engaging the switch which causes a current to pass between the first and second electrodes 19, 20. In the embodiment shown, the heating element 23 is a fuse wire. The current overloads the heating element 23, and causes it to melt and release thermal energy. The heating element 23 is in contact with the electrical insulating material 21, and at the melting temperature of the fuse wire 23 the electrical insulating material 21 is carbonised. This process may include striking the electrical arc between electrodes 19, 20, as referred to above. As used herein, “carbonised”, “carbonisation” and similar terms refer to the conversion of the carbon-containing electrical insulating material 21 to carbon or a carbon-rich residue.

In other embodiments, any other type of heating element 23 can be used. The heating element 23 may comprise a sacrificial overload device, which may be, for example, a fuse wire, as discussed above. Sacrificial devices other than a fuse wire may alternatively be used. In general, the sacrificial overload device should be arranged such that when supplied with a predetermined electrical current the device overheats to a temperature exceeding the carbonisation temperature of the electrical insulating material 21. In some embodiments, there may be no sacrificial overload device. For example, in such embodiments, the heating element 23 may comprise a pre-carbonised tip of the electrical insulating material 21. In these embodiments, the carbonised tip 23, being electrically conductive, serves as a conductive bridge between the two electrodes 19, 20 to initiate the carbonisation of the remaining electrical insulating material 21. In some embodiments, the tip of the electrical insulating material may be carbonised and also connected by means of a sacrificial overload device such as a fuse wire.

Since the carbonised material 21 has a high carbon content it is capable of conducting electricity, and an electrical bridge between the first and second electrodes 19, 20 is thus maintained after the heating element 23 has heated an initial portion of the electrical insulating material 21 to its carbonisation temperature. The electrical current passing between the electrodes 19, 20, together with the exothermic nature of the carbonisation process, helps to cause the native electrical insulating material 21 which is adjacent to the carbonised material to also become carbonised. The carbonisation of the electrical insulating material 21 thereby continues, gradually consuming the electrical insulating material 21 from one end of the heating apparatus 17 to the other. The partition between carbonised and native electrical insulating material 21 migrates at a substantially constant rate along the heating assembly 17.

By this arrangement, the heater 3 utilises the exothermic carbonisation of the electrical insulating material 21 to provide heat. The heat is provided in a narrow circumferential band around the heater 3, in a position substantially corresponding to the region of electrical insulating material 21 that is in the process of being carbonised. Because the carbonisation of the electrical insulating material 21 occurs at the interface between carbonised and native material, the circumferential band of heat provided by the exothermic carbonisation process is relatively narrow. That is, only a relatively small proportion of the longitudinal length of the heater assembly 17 is at an elevated temperature at any given time. The area of elevated temperature provided by the heater assembly is small in comparison to the total surface area of the heater assembly, and may comprise, for example, 10%, 20% or 50% of the total surface area of the heater assembly. The circumferential band of heat provided by the heater 3 is hereinafter referred to as the “heating zone”. To the extent that the electrical insulating material 21 is consistent throughout the length of the heater assembly 17, for example, in terms of its composition, density, thickness, etc., the heating zone will migrate at a substantially constant rate.

The width of the heating zone may in general be influenced by a number of factors. For example, the capacity of the container 18 to conduct heat longitudinally, the rate of migration of the heating zone, the current provided by the energy source 2, and the inherent carbonisation properties of the electrical insulating material 21, may all be contributing factors. In general, the heating zone may be between approximately 1 mm and 20 mm wide.

The rate at which the heating zone migrates may also be influenced by a number of factors. For example, different insulating materials may be carbonised at different temperatures. The thickness of the electrical insulating material 21 may also be important, wherein the rate of migration of the carbonisation may occur more slowly in thicker material. The current provided by the energy source 2 may also be important, wherein the greater the current, the greater the rate of carbonisation. The electrical insulating material 21 may carbonise along its length at a rate of between approximately 5 mm and 30 mm every 60 seconds, thereby providing migration of the heating zone at a corresponding rate.

The carbonisation process continues until the electrical insulating material 21 has been completely carbonised, or until the supply of electrical current is terminated. Once the electrical supply is disconnected, it may be necessary to provide a replacement heating element 23, before the carbonisation process can be restarted. In these embodiments, once switched off or consumed, if the apparatus 1 is to be reused, the heater assembly 17 may be replaced in order to supply the replacement heating element 23.

In other embodiments, the carbonisation process may be restarted even in the absence of a sacrificial overload device or other ignition device 23 between the electrodes. In these embodiments, the carbonised electrical insulating material may be sufficient to provide an electrically conductive bridge between the electrodes suitable to reignite the process.

In use, the apparatus 1 provides volatilized smokeable material compounds for inhalation by the user via the mouthpiece 6.

To use the apparatus 1, the user activates the heater 3 as described above using the switch. As shown in FIG. 1 and discussed above, the heater 3 may be located in a central region of the housing 7, and the heating chamber 4 and smokeable material 5 may be located around the longitudinal surface of the heater 3. In this arrangement, in use, thermal energy emitted by the heater 3 travels in a radial direction outwards from the longitudinal surface of the heater 3 into the heating chamber 4 and the smokeable material 5.

The heater 3 is arranged so that the heating zone produced by the heater 3 migrates towards the second, mouth end 9 of the apparatus 1.

Because the heater 3 provides a narrow circumferential heating zone, it supplies thermal energy to the smokeable material 5 located radially adjacent to that region of the heater 3 without substantially heating the remainder of the smokeable material 5. The heated section of smokeable material 5 may comprise a section, such as a ring, of smokeable material 5 which lies directly circumferentially adjacent to the heating zone produced by the heater 3. In this way, a small distinct section of the smokeable material 5 can be heated individually. The section of smokeable material 5 that is heated has a mass and volume which is significantly less than the body of smokeable material 5 as a whole. Furthermore, since the heating zone produced by the heater 3 migrates along the longitudinal length of the heater 3, the specific section of smokeable material 5 being heated also migrates along the length of the smokeable material 5, and the precise section of smokeable material 5 that is being heated is continually changing.

If the smokeable material 5 comprises tobacco for example, a suitable temperature for volatilizing the nicotine and other aromatic compounds may be above 120° C., such between 150° C. and 250° C. or between 130° C. and 180° C. Therefore, examples of temperatures in the heating zone include 180° C. and 250° C.

The region of the heating assembly that is immediately in front of the heating zone, into which the heating zone is progressing as the progressive carbonisation of the electrical insulating material 21 continues, may be pre-heated by longitudinal thermal conduction along the container 18 from the heating zone. This region may comprise a pre-volatilizing region of the heating assembly, which heats up the smokeable material 5 in preparation for its components to be volatilized by the approaching heating zone. This pre-heating does not heat the smokeable material 5 to a sufficient temperature to volatilize nicotine. A suitable temperature could be less than 120° C., such as approximately 100° C.

Once the heater 3 has been activated, the smokeable material 5 is heated and the user may obtain volatilized smokeable material compounds by drawing on the mouthpiece 6 of the apparatus 1. As the user draws on the mouthpiece 6, air is drawn into the heating chamber 4 of the apparatus 1 via the air conduits 14 and the valves 15. As it is drawn through the heated smokeable material 5 in the heating chamber 4, the air is enriched with smokeable material vapours, such as aroma vapours, before being inhaled by the user at the mouthpiece 6.

Between draws, the valves 15 may be closed so that all volatilized substances remain contained inside the chamber 4 pending the next draw. The partial pressure of the volatilized substances between puffs approaches the saturated vapour pressure and the amount of evaporated substances therefore depends largely on the temperature in the heating chamber 4. This helps to ensure that the delivery of volatilized nicotine and aromatic compounds remains constant throughout the use of the smoking article. The valves 15 open as the user draws on the mouthpiece 6 so that gaseous flow may be drawn through the heating chamber 4 to carry volatilized smokeable material components to the user via the mouthpiece 6. In some embodiments, a membrane may be located in the valves 15 to ensure that no oxygen enters the chamber 4. The valves 15 may be breath-actuated so that they open when the user draws on the mouthpiece 6. The valves 15 may close when the user stops drawing. Alternatively, the valves 15 may, for example, close following the elapse of a predetermined period after their opening. Optionally, a mechanical or other suitable opening/closing arrangement may be present so that the valves 15 open and close automatically.

In an alternative configuration of heater 3, the heater 3 comprises a spiral-shape or helical heater 3. The smokeable material 5 may be configured to screw onto the spiral-shape heater 3. The spiral-shape heater 3 may comprise a spiral-shape container 18 containing a spiral-shape heater assembly 17 so as to operate in substantially the same manner as the linear, elongate heater 3 described above.

In general, in apparatus of the type described herein, the length of the housing 7 may be approximately 130 mm, the length of the energy source may be approximately 59 mm, and the length of the heater 3 and heating region 4 may be approximately 50 mm. Other embodiments may have different dimensions. The diameter of the housing 7 may be between approximately 15 mm and approximately 18 mm. For example, the diameter of the housing's first end 8 may be 18 mm whilst the diameter of the mouthpiece 6 at the housing's second end 9 may be 15 mm. The depth of the heating chamber 4 may be approximately 5 mm and the heating chamber 4 may have an exterior diameter of approximately 10 mm. The diameter of the energy source 2 may be between approximately 14 mm and approximately 15 mm, such as for example 14.6 mm.

In the embodiment shown in FIGS. 1-3, the diameter of the heater 3 may be between approximately 2 mm and approximately 6 mm. The diameter of the heater 3 may, for example, be between approximately 4 mm and approximately 4.5 mm or between approximately 2 mm and approximately 3 mm. Heater diameters outside these ranges may alternatively be used.

In other embodiments, the apparatus may comprise different heater arrangements, which nevertheless work in accordance with the same principle and offer the same advantages as those relating to the embodiments described above.

In some embodiments, for example, the apparatus 1 may comprise a plurality of heaters 3 of the type described above in respect of the embodiment shown in FIGS. 1-3. Example embodiments are shown in FIGS. 4B and 4C. For comparison, FIG. 4A is a diagram showing the arrangement of smokeable material 5 and heater 3 of the embodiment shown in FIGS. 1-3. As described above, in this embodiment, the heater 3 is positioned in the centre of the smokeable material 5. FIGS. 4B and 4C show related embodiments in which the apparatus 1 comprises two and three heaters 3, respectively. In other embodiments, the apparatus may comprise any suitable number of heaters, such as four, five, six, eight, ten, twelve, or more heaters. The plurality of heaters 3 may have any arrangement within the smokeable material 5. In the embodiments shown in FIGS. 4B and 4C, the heaters 3 are positioned within the smokeable material 5 such that they are evenly spaced in order to most efficiently heat the smokeable material 5. In embodiments comprising a plurality of heaters 3, the same considerations regarding the arrangement of smokeable material 5 apply as described above in respect of the embodiment of FIG. 1. In particular, the smokeable material 5 should fit within the heating chamber 4 in a suitable manner to efficiently receive thermal energy from the heaters 3.

In some embodiments in which the apparatus 1 comprises a plurality of heaters 3, the heaters are generally arranged such that the narrow circumferential heating zone produced by each heater 3 migrates along the heater 3 at substantially the same rate, so that a narrow section of the smokeable material 5 is heated. In other embodiments, however, the heating zones of the different heaters may migrate at different rates. For example, the apparatus 1 may be provided with a heating zone which progresses at a faster rate than the other heating zones so as to provide the pre-heating effect referred to previously.

In some embodiments the arrangement of the heater assembly 17 within the heater 3 may be different to that described above and shown in FIGS. 3 and 4.

In the embodiment shown in FIG. 5A, the heater assembly 17 comprises a plurality of first electrodes 19 and a plurality of second electrodes 20. The first and second electrodes 19, 20 comprise rods of electrically conductive material, such as copper as described previously, which extend from one end of the heater to the other. The rods may be approximately 0.5 mm in diameter, although other diameters could alternatively be used.

As explained previously, all of the electrodes 19, 20 are embedded within the electrical insulating material 21. The electrodes 19, 20 are also separated and electrically isolated from one another by the electrical insulating material 21. The electrical insulating material 21 is capable of being carbonised. In the embodiment shown in FIG. 5A, the electrical insulating material 21 comprises a wood pulp material which is in close contact with both the first and second electrodes 19, 20, although other materials could be used.

Each of the first electrodes 19 is connected to one of the second electrodes 20 by a heating element 23, such as a short length of fuse wire, to form a number of electrode pairs. Each of the heating elements 23 is also embedded within and thus in close contact with the insulating material 21.

As described above, the heater 3 is activated by passing a current between each of the paired first and second electrodes 19, 20. The current causes the heating element 23 connecting the electrodes to release thermal energy. The heating elements 23 are in contact with the electrical insulating material 21, and heat an initial portion of the electrical insulating material 21 to its carbonisation temperature. A heating zone is thus established which migrates along the length of the heater assembly 17 as described above in respect of other heater embodiments. In the embodiment of FIG. 5A, carbonisation of the electrical insulating material 21 is driven by electrical bridges between the first and second electrodes 19, 20 within each of the electrode pairs.

This heater assembly arrangement may be advantageous, for example, to drive faster migration of the heating zone, to generate a heating zone having an increased temperature, or for use in connection with different electrical insulating materials, for example, thicker or denser electrical insulating materials, which may have different properties such as different carbonisation temperatures.

In the embodiment shown in FIG. 5B, the heater 3 is composed of a number of co-axial layers. The heater assembly 17 comprises first and second electrodes 19, 20, and these electrodes 19, 20 are separated and electrically isolated from one another by an electrical insulating material 21.

The first electrode 19 comprises the core of the heater assembly 17, and extends from one end of the heater 3 to the other. It may comprise a copper rod and may be approximately 0.5 mm in diameter although, as referred to previously, other diameters could alternatively be used.

The first electrode 19 is encompassed by an electrical insulating material 21. The electrical insulating material 21 electrically isolates the first and second electrodes 19, 20. In addition, the electrical insulating material 21 is capable of being carbonised. In the embodiment shown in FIG. 5B, the electrical insulating material 21 comprises a paper material which is tightly wrapped around the first electrode. All of the circumferential surface of the first electrode 19 is in close contact with the electrical insulating material 21. Other carbonisable electrical insulating materials 21 may alternatively be used.

The second electrode 20 is arranged to form part of an external surface of the heater assembly 17. The second electrode 20 is configured to minimally inhibit the transfer of heat produced by the carbonisation of the electrical insulating material 21 to the heating chamber 4. In the embodiment shown in FIG. 5B, the second electrode comprises a plurality of fine strands of copper wire extending longitudinally along the circumferential surface of the electrical insulating material 21. In some embodiments, for example, the fine strands may be woven to form a mesh, or one or more wires may be wound around the electrical insulating material 21.

The first electrode 19 is connected to each of the fine strands comprising the second electrode 20 by a plurality of heating elements 23, such as short fuse wires 23, which are also in close contact with the electrical insulating material 21.

The heater 3 is activated by passing a current between the first and second electrodes 19, 20. The current activates the plurality of heating elements 23 and causes them to release thermal energy. The heating elements 23 are in contact with the electrical insulating material 21, and heat an initial portion of the electrical insulating material 21 to its carbonisation temperature. A heating zone is thus established which migrates along the length of the heater assembly 17 as described above in respect of other heater assembly embodiments.

In some embodiments, the apparatus 1 may comprise a heater 3 which extends circumferentially around the outer surface of the smokeable material 5. In particular, the heater 3 may comprise a substantially elongate tube, which may be cylindrical, wherein the heating chamber 4 is located inside the hollow centre of the tube 3 rather than around the heater's outer circumference.

Exemplary embodiments of this arrangement are shown in FIGS. 6A, 6B, and 6C.

In the embodiment shown in FIG. 6A the heater 3 comprises a plurality of heater assemblies 17 of the type described above in relation to the embodiment of FIGS. 1-3. The plurality of heater assemblies 17 extend longitudinally along the length of the heater 3 and are circumferentially arranged around the heater 3 within the container 18. The heater assemblies 17 are generally arranged such that the heating zone produced by each heater assembly 17 migrates along the heater 3 at the same rate, so that only a narrow section, such as a disk-section, of the smokeable material 5 is heated to a volatilizing temperature at any one time.

The heater 3 shown in FIG. 6A comprises a number of heater assemblies 17 within a single container 18. In other embodiments, however, each of the heater assemblies 17 may be contained within a dedicated container 18, such that the heater 3 comprises a plurality of individual heaters.

FIG. 6B shows an alternative embodiment in which the circumferential heater 3 is similar to that described in connection with FIG. 5A. The heater assembly 17 comprises a plurality of first electrodes 19 and a plurality of second electrodes 20, distributed within the container 18 around the circumference of the heater 3. The first and second electrodes 19, 20 comprise rods of electrically conductive material, such as copper rods, which extend from one end of the heater 3 to the other. As described previously, the rods may have a diameter of approximately 0.5 mm, although other diameters could alternatively be used.

All of the electrodes 19, 20 are embedded within an electrical insulating material 21. The electrodes 19, 20 are also separated and electrically isolated from one another by the electrical insulating material 21. The electrical insulating material 21 is capable of being carbonised and in the embodiment shown in FIG. 6B, the insulating material 21 comprises a wood pulp material although other materials could be used.

Each of the first electrodes 19 is connected to one of the second electrodes 20 by a heating element 23, such as a short length of fuse wire, to form a number of electrode pairs. Each of the heating elements 23 is also embedded within and thus in close contact with the insulating material 21.

As described above, the heater 3 is activated by passing a current between each of the paired first and second electrodes 19, 20. The current activates the heating element 23 connecting the electrodes and causes it release thermal energy. The heating elements 23 are in contact with the electrical insulating material 21, and heat an initial portion of the electrical insulating material 21 to its carbonisation temperature. A heating zone is thus established which migrates along the length of the heater assembly 17 as described above in respect of other heater embodiments. In the embodiment of FIG. 6B, carbonisation of the electrical insulating material 21 is driven by electrical bridges formed between the first and second electrodes 19, 20 within each of the electrode pairs.

Another embodiment is shown in FIG. 6C. The heater arrangement of this embodiment works in a manner analogous to that described above with reference to FIG. 5B.

The heater assembly 17 comprises first and second electrodes 19, 20, and these electrodes 19, 20 are separated and electrically isolated from one another by an electrical insulating material 21.

The first electrode 19 comprises the outer casing of the heater assembly 17, and may, for example, comprise a copper tube which extends from one end of the heater 3 to the other.

Within the tubular first electrode 19 is an electrical insulating material 21. The electrical insulating material 21 electrically isolates the first and second electrodes 19, 20. In addition, the electrical insulating material 21 is capable of being carbonised. In the embodiment shown in FIG. 6C, the electrical insulating material 21 comprises a paper material which lines the tubular first electrode 19 although other materials could be used.

The second electrode 20 forms the innermost layer of the tubular heater assembly 17. In the embodiment shown in FIG. 5B, the second electrode comprises a mesh comprising a plurality of fine strands of copper wire extending longitudinally along the inner surface of the electrical insulating material 21.

The first electrode 19 is connected to each of the fine strands comprising the second electrode 20 by a plurality of heating elements 23 such as short fuse wires, which are also in close contact with the electrical insulating material 21.

The heater 3 is activated by passing a current between the first and second electrodes 19, 20. The current activates the plurality of heating elements 23 and causes them to release thermal energy. The heating elements 23 are in contact with the electrical insulating material 21, and heat an initial portion of the electrical insulating material 21 to its carbonisation temperature. A heating zone is thus established which migrates along the length of the heater assembly 17 as described above in respect of other heater assembly embodiments.

In each of the embodiments in which the heater 3 is a circumferential heater positioned around the periphery of the heating chamber 4, the heater assembly 17 is enclosed within a container 18. The same considerations regarding the container apply as discussed above in connection with the embodiment shown in FIGS. 1-3. In general, any suitable arrangement of container may be used which permits the efficient conduction of thermal energy from the inside to the outside of the heater 3 in a radial direction to the smokeable material 5, but inhibits or reduces the conduction of thermal energy longitudinally along the length of the heater 3. The container 18 may in some embodiments comprise a vent, which may comprise a one-way valve, to allow any gases produced by the heater assembly 17 to escape from the container. However, the vent is generally not in fluid communication with the smokeable material 5 or mouthpiece 6 so that any gases emitted by the heater assembly 17 cannot dilute the aromatic compounds and nicotine, if present, released from the smokeable material 5, and cannot be inhaled by the user.

In some embodiments, the heating chamber 4 may be heated by heaters 3 positioned within the chamber 4, for example, as shown in FIGS. 1-5, and also by a heater 3 positioned circumferentially around the periphery of the chamber, as shown, for example, in FIG. 6.

In general, the electrical insulating material 21 of any embodiment may comprise any electrically insulating, carbonisable material. Suitable materials may be naturally occurring materials or derived from naturally occurring materials such as, for example, cellulosic or fibrous materials such as wood pulp, flax, bast, cotton, hemp, alginates, or nut shell materials such as coconut shell. Synthetic materials may also be used, such as, for example, resins (such as novolak or other phenolic resins). The resin material may be coated on to the surface of the electrodes or the electrodes could be buried within the resin.

In general, the first and second electrodes 19, 20 may comprise any electrically conductive material. The electrodes 19, 20 may comprise the same or different materials. In some embodiments, the electrodes 19, 20 may be durable and not consumed during the operation of the heater 3. In other embodiments, one or more of the electrodes 19, 20 may be consumed when the heater 3 is in use, for example one or more of the electrodes 19, 20 may comprise carbon material.

The mass of the smokeable material 5 which is heated by the heater 3 may be in the range of 0.2 to 1 g. The temperature to which the smokeable material 5 is heated may be user controllable, for example to any temperature within the temperature range of 120° C. to 250° C. as previously described The temperature to which the smokeable material 5 is heated to volatilize components of the smokeable material 5 may be, for example, any temperature within the temperature range of 120° C. to 250° C. as previously described. The mass of the apparatus 1 as a whole may be in the range of 70 to 125 g, although a smaller mass is also possible. An example battery 2 has a capacity of 1000 to 3000 mAh and a voltage of 3.7V.

In some embodiments, the smokeable material 5 may be comprised in a cartridge which can be inserted into the heating chamber 4. For example, as shown in FIGS. 1 and 2, the cartridge may comprise a smokeable material tube 5 which can be introduced into the apparatus 1 by removal of the mouthpiece 6 and insertion against the buffer 16. The smokeable material cartridge fits around the heater 3 so that the internal surface of the smokeable material tube 5 faces an outer longitudinal surface of the heater 3, such that the tube 5 is a close fit around the heater 3 to ensure efficient heat transfer. Alternatively, for example as shown in FIGS. 6A to 6C, the cartridge may comprise a substantially solid body of smokeable material which can be inserted into a bore-type heating cavity 4, in which one or a plurality of heaters 3 is arranged around the periphery of the bore. As with the tube-type cartridge referred to above, the solid cartridge can be inserted into the heating chamber 4 by removal of the mouthpiece 6 and insertion against the buffer 16. The external surface of the body of smokeable material 5 faces the longitudinal interior surface of the heater 3, such that the smokeable material body 5 is a close fit inside the bore-like heating chamber 4 to ensure efficient heat transfer. The cartridge 5 is generally not longer than the heater 3 and may be approximately equal to the length of the heater 3 so that the heater 3 can heat the cartridge 5 along its whole length.

In some embodiments, the thermal insulation 11 may be provided as part of the smokeable material cartridge 5, located co-axially around the outside of the smokeable material 5.

An advantage of the apparatus 1, and in particular the heater 3, is that there is no requirement for a dedicated control system to regulate the heating of the smokeable material 5, and/or to adjust the section of smokeable material that is being heated. Instead, once the disclosed apparatus is activated, a small section of the smokeable material 5 is heated and the area of heating migrates at a substantially constant rate from one end of the smokeable material 5 to the other. Furthermore, the degree of heat and the rate of migration can easily be controlled and predetermined by adjusting the composition and arrangement of the heater assembly 17.

A further advantage of this arrangement is that activating only a small portion of the heater 3 means that the energy required to heat the smokeable material 5 is reduced in comparison to that required to heat the full amount of smokeable material over the entire period of use of the article 1.

Furthermore, much of the thermal energy provided by the heater 3 is supplied by the chemical energy that is released upon the exothermic carbonisation of the electrical insulating material 21, and not all of the thermal energy is derived from the energy source 2. Thus, the required power output of the energy source 2 is reduced. This means that a smaller and lighter energy source 2 can be installed in the apparatus 1.

A further advantage is that once activated the apparatus is permanently ready and able to provide smokeable material components to the user because the smokeable material is continually being heated. This allows the aromatics, and nicotine if present, to be inhaled by the user without substantial delay, for example, whilst a heater is activated to heat the smokeable material in response to detection of the user drawing on the apparatus.

It will be appreciated that any of the alternatives described above can be used singly or in combination. For example, as discussed above, the heater 3 may be located around the outside of the smokeable material 5 rather than the smokeable material 5 being located around the heater 3. The heater 3 may therefore circumscribe the smokeable material 5 to apply heat to the smokeable material 5 in a substantially radially inward direction.

Although the heating element 23 has predominately been described as a fuse wire, it will be appreciated that any of the embodiments may employ an alternative heating element 23 to initiate carbonisation of the insulating material 21.

In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration and example various embodiments in which the claimed invention may be practised and which provide for a superior apparatus arranged to heat but not burn smokable material. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. They are presented only to assist in understanding and teach the claimed and otherwise disclosed features. It is to be understood that advantages, embodiments, examples, functions, features, structures and/or other aspects of the disclosure are not to be considered limitations on the disclosure 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 and/or spirit of the disclosure. Various embodiments may suitably comprise, consist of, or consist in essence of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. The disclosure may include other inventions not presently claimed, but which may be claimed in future.

Claims

1. An apparatus configured to heat smokeable material to volatilize at least one component of the smokeable material, wherein the apparatus comprises a heater comprising a carbonisable electrical insulating material, and wherein the heater is arranged to carbonise the electrical insulating material to cause progressive heating of the smokeable material.

2. The apparatus according to claim 1, wherein the heater is configured to trigger carbonisation of the electrical insulating material.

3. The apparatus according to claim 1, wherein the heater is configured to trigger carbonisation of the electrical insulating material in response to a user action.

4. The apparatus according to claim 1, wherein the heater is configured to trigger carbonisation of the electrical insulating material by heating the electrical insulating material to a carbonisation temperature of the electrical insulating material.

5. The apparatus according to claim 1, wherein the electrical insulating material is configured to progressively carbonise from a first end of the heater to a second end of the heater in response to carbonisation being initially triggered by the heater.

6. The apparatus according claim 5, wherein the apparatus is arranged to progressively heat the smokeable material by the progressive carbonisation of the electrical insulating material.

7. The apparatus according to claim 1, wherein the heater comprises a plurality of electrodes which are separated and electrically isolated by the electrical insulating material.

8. The apparatus according to claim 7, configured to trigger carbonisation of the electrical insulating material by causing a current to pass between electrodes.

9. The apparatus according to claim 8, wherein the electrical insulating material is carbonised to provide an electrically conductive bridge between electrodes of opposite polarity.

10. The apparatus according to claim 7, wherein the heater is arranged to pass a current between electrodes of opposite polarity to cause progressive carbonisation of the electrical insulating material to occur from a first end of the heater to a second end of the heater.

11. The apparatus according to claim 1, wherein the heater is positioned in a cavity within a charge of smokeable material.

12. The apparatus according to claim 1, wherein the heater is enclosed within a gas-impermeable container.

13. The apparatus according to claim 12, wherein the container is thermally conductive, and wherein the thermal conductivity of the container is greater in a lateral dimension than in a longitudinal dimension.

14. The apparatus according to claim 1, wherein the electrical insulating material is a cellulosic material.

15. The apparatus according to claim 14, wherein the electrical insulating material comprises a paper material.

16. The apparatus according to claim 1, configured to heat the smokeable material without combusting the smokeable material.

17. The apparatus according to claim 1, wherein the heater is positioned around a periphery of a charge of smokeable material.

18. The apparatus according to claim 1, wherein the electrical insulating material is a fibrous material.

19. The apparatus according to claim 1, wherein the electrical insulating material is a resin.