Patent Description:
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.

<CIT> describes an article for use with apparatus for heating smokable material.

<CIT> describes an apparatus for heating smokable material and an article for use therewith.

<CIT> describes an aerosol generating article with internal susceptor.

<CIT> describes an aerosol generating article with multi-material susceptor.

<CIT> describes a smoke generating device.

A first aspect of the present invention provides a heating element as defined in claim <NUM> for use in heating aerosolisable material to volatilise at least one component of the aerosolisable material, wherein the heating element comprises a heat resistant support and a coating on the support, and wherein the coating comprises cobalt.

In an exemplary embodiment, the heating element is planar or substantially planar.

In an exemplary embodiment, the heating element is tubular or substantially tubular.

In an exemplary embodiment, the coating is located radially outwards of the support.

In an exemplary embodiment, the coating has a thickness of no more than <NUM> microns. In an exemplary embodiment, the coating has a thickness of no more than <NUM> microns.

The support comprises one or more materials selected from the group consisting of: a metal, or a metal alloy. In an exemplary embodiment, the support comprises stainless steel.

In an exemplary embodiment, the heating element comprises a heat resistant protective coating, and the coating comprising cobalt is located between the support and the heat resistant protective coating.

In an exemplary embodiment, the cobalt coating is encapsulated. In an exemplary embodiment, the heat resistant protective coating and the support together encapsulate the cobalt coating. In an exemplary embodiment, the heat resistant protective coating encapsulates the cobalt coating and the support.

In an exemplary embodiment, the heat resistant protective coating comprises one or more materials selected from the group consisting of: a ceramics material, metal nitride, titanium nitride, and diamond.

In an exemplary embodiment, the heat resistant protective coating has a thickness of no more than <NUM> microns. In an exemplary embodiment, the heat resistant protective coating has a thickness of no more than <NUM> microns.

A second aspect of the present invention provides an article as defined in claim <NUM> for use with apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material, wherein the article comprises the heating element of the first aspect of the present invention, and aerosolisable material in thermal contact with the heating element.

In an exemplary embodiment, the aerosolisable material is in surface contact with the heating element.

In an exemplary embodiment, the aerosolisable material is reconstituted, cellulosic, or in gel form.

In an exemplary embodiment, the aerosolisable material comprises tobacco and/or one or more humectants.

In an exemplary embodiment, the article is substantially cylindrical.

A third aspect of the present invention provides a system as defined in claim <NUM> for heating aerosolisable material to volatilise at least one component of the aerosolisable material, the system comprising: the article of the second aspect of the present invention; and apparatus for heating the aerosolisable material of the article to volatilise at least one component of the aerosolisable material of the article, the apparatus comprising a heating zone for receiving the article, and a device for causing heating of the heating element of the article when the article is in the heating zone.

In an exemplary embodiment, the device comprises a magnetic field generator for generating a varying magnetic field for penetrating the heating element of the article when the article is in the heating zone.

A fourth aspect of the present invention provides apparatus as defined in claim <NUM> for heating aerosolisable material to volatilise at least one component of the aerosolisable material, the apparatus comprising: a heating zone for receiving an article comprising aerosolisable material; the heating element of the first aspect of the present invention for heating the heating zone; and a device for causing heating of the heating element.

In an exemplary embodiment, the device comprises a magnetic field generator for generating a varying magnetic field for penetrating the heating element in use.

In an exemplary embodiment, the heating element projects into the heating zone.

A fifth aspect of the present invention provides a system as defined in claim <NUM> for heating aerosolisable material to volatilise at least one component of the aerosolisable material, the system comprising: the apparatus of the fourth aspect of the present invention; and the article for locating in the heating zone of the apparatus.

As used herein, the term "aerosolisable material" includes materials that provide volatilised components upon heating, typically in the form of vapour or an aerosol. "Aerosolisable material" may be a non-tobacco-containing material or a tobacco-containing material. "Aerosolisable material" may, for example, include one or more of tobacco per se, tobacco derivatives, expanded tobacco, reconstituted tobacco, tobacco extract, homogenised tobacco or tobacco substitutes. The aerosolisable material can be in the form of ground tobacco, cut rag tobacco, extruded tobacco, reconstituted tobacco, reconstituted aerosolisable material, liquid, gel, gelled sheet, powder, or agglomerates, or the like. "Aerosolisable material" also may include other, non-tobacco, products, which, depending on the product, may or may not contain nicotine. "Aerosolisable material" may comprise one or more humectants, such as glycerol or propylene glycol.

As used herein, the term "heating material" or "heater material" refers to material that is heatable by penetration with a varying magnetic field.

Induction heating is a process in which an electrically-conductive object is heated by penetrating the object with a varying magnetic field. The process is described by Faraday's law of induction and Ohm's law. An induction heater may comprise an electromagnet and a device for passing a varying electrical current, such as an alternating current, through the electromagnet. When the electromagnet and the object to be heated are suitably relatively positioned so that the resultant varying magnetic field produced by the electromagnet penetrates the object, one or more eddy currents are generated inside the object. The object has a resistance to the flow of electrical currents. Therefore, when such eddy currents are generated in the object, their flow against the electrical resistance of the object causes the object to be heated. This process is called Joule, ohmic, or resistive heating. An object that is capable of being inductively heated is known as a susceptor.

It has been found that, when the susceptor is in the form of a closed electrical circuit, magnetic coupling between the susceptor and the electromagnet in use is enhanced, which results in greater or improved Joule heating.

Magnetic hysteresis heating is a process in which an object made of a magnetic material is heated by penetrating the object with a varying magnetic field. A magnetic material can be considered to comprise many atomic-scale magnets, or magnetic dipoles. When a magnetic field penetrates such material, the magnetic dipoles align with the magnetic field. Therefore, when a varying magnetic field, such as an alternating magnetic field, for example as produced by an electromagnet, penetrates the magnetic material, the orientation of the magnetic dipoles changes with the varying applied magnetic field. Such magnetic dipole reorientation causes heat to be generated in the magnetic material.

When an object is both electrically-conductive and magnetic, penetrating the object with a varying magnetic field can cause both Joule heating and magnetic hysteresis heating in the object. Moreover, the use of magnetic material can strengthen the magnetic field, which can intensify the Joule and magnetic hysteresis heating.

In each of the above processes, as heat is generated inside the object itself, rather than by an external heat source by heat conduction, a rapid temperature rise in the object and more uniform heat distribution can be achieved, particularly through selection of suitable object material and geometry, and suitable varying magnetic field magnitude and orientation relative to the object. Moreover, as induction heating and magnetic hysteresis heating do not require a physical connection to be provided between the source of the varying magnetic field and the object, design freedom and control over the heating profile may be greater, and cost may be lower.

During induction heating, energy from a varying magnetic field is transferred to the susceptor to induce one or more varying currents in the susceptor, causing the temperature of the susceptor to rise. In order that the susceptor heats up as efficiently as possible, the transfer of energy to the susceptor should be as lossy as possible, so that the energy in the currents is quickly converted to heat. Reducing the thermal mass of the susceptor increases the change in temperature for a given energy input, and reducing the overall magnitude of the induced currents can help to reduce or avoid energy being reflected back into the magnetic field generator.

In producing a practical system for a consumer product, many aspects have to be taken into account, including cost, material availability, ease of forming during manufacture and longevity (including resistance to corrosion). Although mild steel has some of these benefits, due to its vulnerability to corrosion it may be unsuitable for prolonged use. Additionally, and possibly due to reasons linked with its vulnerability to corrosion, very thin sheets of mild steel have limited availability.

Conversely, stainless steel is more widely available and is far more robust than mild steel in use. Unfortunately, for an induction heating system, its use is limited due to a lack of ferromagnetic properties. From the perspective of ohmic heating, stainless steel can be around six to seven times more resistive than mild steel, but the ability of stainless steel to be magnetised is negligible due to its value of relative permeability (µr) being around one. By way of comparison, the corresponding value for mild steel can be about one hundred. There are some stainless-steel alloys that have higher values of value of relative permeability (µr), such as the <NUM> grades of stainless steel, but these tend to lie at the specialist ends of the market and are not widely available, particularly in thin cross sections.

The present invention is predicated on a finding of the inventors of how an acceptable compromise between cost and performance can be achieved to produce a practical induction heater susceptor.

For conductive (and magnetisable) media there is a characteristic depth (the "skin depth") into which the electromagnetic field is able to penetrate. In mild steel, the electromagnetic field will penetrate with an exponential dependence on distance from the surface. Therefore, the field strength, and by implication the energy contained therein, will be mostly absorbed in approximately <NUM> microns of material. The calculation for stainless steel gives a characteristic absorption depth of approximately <NUM> microns, indicating that a much thicker susceptor would be needed to extract the same amount of energy from a given magnetic field.

The present inventors have found that, if a surface of a heating element, such as a surface facing the magnetic field generator, is coated with a thin coating (such as a few microns) of pure nickel, then the coating need only be approximately <NUM> microns thick to effect the same absorption as a thicker mild steel plate. The nickel could for example be applied by a chemical plating method, an electro-chemical plating method, or by vacuum evaporation. Moreover, if cobalt is used instead of nickel, the coating or layer thickness can be reduced to approximately <NUM> microns. A thickness of one or more skin depths should help to ensure that a majority of the available energy is directed into the susceptor. A thickness of around two skin depths may be optimal in some embodiments. Cobalt also can be applied by plating.

Furthermore, cobalt has a higher Curie point temperature than nickel (around <NUM>,<NUM> to <NUM>,<NUM> degrees Celsius, versus <NUM> to <NUM> degrees Celsius). The Curie point temperature, or Curie Temperature, is the temperature at which certain magnetic materials undergo a sharp change in their magnetic properties. It is understood that the Curie point temperature is the temperature below which there is spontaneous magnetisation in the absence of an externally applied magnetic field, and above which the material is paramagnetic. For example, the Curie point temperature is the magnetic transformation temperature of a ferromagnetic material between its ferromagnetic and paramagnetic phase. When such a magnetic material reaches its Curie point temperature, its magnetic permeability reduces or ceases, and the ability of the material to be heated by penetration with a varying magnetic field also reduces or ceases. That is, it may not be possible to heat the material above its Curie point temperature by magnetic hysteresis heating. As cobalt has a Curie point temperature well above the normal operating temperatures of heating elements of embodiments of the present invention, the effect of the Curie point temperature will be much less pronounced (or even, in some embodiments, indiscernible) during normal operation than if nickel were to be used instead.

The support on which the cobalt coating or layer is provided need not interact with the applied varying magnetic field to generate heat in the support. That is, the support need not itself be heatable by penetration with a varying magnetic field. All the support need be able to achieve is supporting the cobalt coating while resisting the heat generated therein. Accordingly, the support can be made from any suitable heat resistant material. Example materials are aluminium, steel, copper, and high temperature polymers such as polyether ether ketone (PEEK) or Kapton.

Accordingly, heating elements of example embodiments of the present invention enable efficient transfer of energy from a varying magnetic field into the heating element while retaining the benefits of relatively low cost, ease of material availability, and ease of forming during manufacture.

The cobalt coating may become increasingly susceptible to oxidation as it increases in temperature. This can increase heat loss due to radiation by increasing the relative emissivity (εr) relative to the unoxidised metal surface, enhancing the rate at which energy is lost through radiation. If the energy radiated ends up being lost to the environment, then such radiation can reduce the system energy efficiency. Oxidation can also reduce the resistance of the cobalt coating to chemical corrosion, which could result in shortening the service life of the heating element. In some embodiments, therefore, the cobalt coating is coated with a heat resistant protective coating, such as titanium nitride. Titanium nitride can be applied using physical vapour deposition, for example. Other example heat resistant protective coatings are a ceramics material, metal nitride, and diamond. In some embodiments, the heat resistant protective coating can be provided in a different way, such as by chemically treating the cobalt coating to encourage growth of a protective film over the cobalt coating, or formation of a protective oxide layer using a process such as anodisation. In addition to protecting the underlying cobalt coating from oxidation, the heat resistant protective coating may also help to physically protect the cobalt coating from mechanical wear. In some embodiments, the cobalt coating is encapsulated. In some embodiments, the heat resistant protective coating and the support may together encapsulate the cobalt coating. In some embodiments, the heat resistant protective coating may encapsulate the cobalt coating and the support.

In some embodiments, the heat resistant protective coating may have low or no electrical conductivity, so as not to (or not to significantly) result in the induction of electric currents in the heat resistant protective coating rather than the cobalt coating.

Some example embodiments will now be described with reference to the drawings.

<FIG> shows a schematic cross-sectional side view of an example of a heating element according to an embodiment of the invention. The heating element <NUM> is for use in heating aerosolisable material to volatilise at least one component of the aerosolisable material. The heating element <NUM> may be for use in apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material, and/or may be for use in an article for use with apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material. The heating element <NUM> is planar or substantially planar. However, in other embodiments the heating element <NUM> may be non-planar.

The heating element <NUM> comprises a heat resistant support 1a. The heat resistant support 1a of this embodiment comprises steel, and more specifically stainless steel. However, in other embodiments, the heat resistant support 1a may for example comprise one or more materials selected from the group consisting of: a metal, a metal alloy, a ceramics material, and a plastics material. For example, in some embodiments, the heat resistant support 1a may comprise steel, mild steel, aluminium, copper, or a high temperature polymer such as polyether ether ketone (PEEK) or Kapton.

The heating element <NUM> comprises a layer, film or coating 1b on the support 1a. The coating 1b comprises cobalt. In this embodiment, the cobalt coating 1b has a thickness of about <NUM> microns. However, in other embodiments, the cobalt coating 1b may have a different thickness, such as a thickness of no more than <NUM> microns or no more than <NUM> microns. The coating may be a plating.

<FIG> shows a schematic cross-sectional side view of an example of another heating element according to an embodiment of the invention. The heating element <NUM> of <FIG> comprises a heat resistant support 2a, and a coating 2b comprising cobalt located on the support 2a. The heating element <NUM> may be for use in apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material, and/or may be for use in an article for use with apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material.

The heating element <NUM> is planar or substantially planar. However, in other embodiments the heating element <NUM> may be non-planar. The heating element <NUM> of <FIG> is the same as the heating element <NUM> of <FIG> except that the heating element <NUM> of <FIG> also comprises a heat resistant protective coating 2c. The heat resistant protective coating 2c is provided on the cobalt coating 2b. More specifically, the cobalt coating 2b is located between the support 2a and the heat resistant protective coating 2c. The heat resistant protective coating 2c of this embodiment comprises titanium nitride. However, in other embodiments, the heat resistant protective coating 2c may for example comprise one or more materials selected from the group consisting of: a ceramics material, metal nitride, titanium nitride, and diamond. In this embodiment, the heat resistant protective coating 2c has a thickness of about <NUM> microns. However, in other embodiments, the heat resistant protective coating 2c may have a different thickness, such as a thickness of no more than <NUM> microns or no more than <NUM> microns. Any of the herein-described possible variations to the embodiment of <FIG> may be made to the embodiment of <FIG> to form further embodiments.

<FIG> shows a schematic cross-sectional side view of an example of another heating element according to an embodiment of the invention. The heating element <NUM> of <FIG> comprises a heat resistant support 3a, a coating 3b comprising cobalt located on the support 3a, and a heat resistant protective coating 3c arranged so that the cobalt coating 3b is located between the support 3a and the heat resistant protective coating 3c. The heating element <NUM> may be for use in apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material, and/or may be for use in an article for use with apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material.

The heating element <NUM> is planar or substantially planar. However, in other embodiments the heating element <NUM> may be non-planar. The heating element <NUM> of <FIG> is the same as the heating element <NUM> of <FIG> except that, in the embodiment of <FIG>, the cobalt coating 2b and the heat resistant protective coating 2c are located only on one side of the heat resistant support 2a, whereas in the embodiment of <FIG> the cobalt coating 3b and the heat resistant protective coating 3c are located on each of two opposite major sides of the heat resistant support 3a. That is, in the embodiment of <FIG>, the support 3a is located between two volumes of the cobalt coating 3b, and the combination of the support 3a and the volumes of the cobalt coating 3b is located between two volumes of the heat resistant protective coating 3c. In another embodiment, the heat resistant protective coating 3c may be omitted or provided on only one side of the combination of the support 3a and the volumes of the cobalt coating 3b. Any of the herein-described possible variations to the embodiments of <FIG> may be made to the embodiment of <FIG> to form further embodiments.

<FIG> shows a schematic cross-sectional side view of an example of a heating element according to another embodiment of the invention. The heating element <NUM> of <FIG> again comprises a heat resistant support 4a, a coating 4b comprising cobalt located on the support 4a, and a heat resistant protective coating 4c arranged so that the cobalt coating 4b is located between the support 4a and the heat resistant protective coating 4c. The heating element <NUM> may be for use in apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material, and/or may be for use in an article for use with apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material.

In this embodiment, the heating element <NUM> is substantially cylindrical with a substantially circular cross section, but in other embodiments the heating element <NUM> may have an oval or elliptical cross section or be other than cylindrical. In some embodiments, the heating element <NUM> may have a polygonal, quadrilateral, rectangular, square, triangular, star-shaped, or irregular cross section, for example. In this embodiment, the heating element <NUM> is tubular with a hollow inner region 4d. In other embodiments, the heating element <NUM> may have an axially-extending gap in its circumference yet the heating element <NUM> may still be substantially tubular. In some embodiments, the heating element <NUM> may be a rod. In some embodiments, material, such as aerosolisable material, may be located in, or fill, the inner region 4d.

In this embodiment, the heating element <NUM> is elongate and has a longitudinal axis A-A. In other embodiments, the heating element <NUM> is may not be elongate. In some such other embodiments, the heating element <NUM> is still has an axial direction A-A that is perpendicular to the cross section of the heating element <NUM>.

In this embodiment, the cobalt coating 4b is located radially outwards of the heat resistant support 4a. That is, the cobalt coating 4b is on an outer side of the heat resistant support 4a. Moreover, in this embodiment, a radially inward facing side of the heat resistant support 4a is free from a cobalt coating 4b. In other embodiments, a cobalt coating 4b may be provided radially inwards of the heat resistant support 4a in addition to, or alternatively to, radially outwards of the heat resistant support 4a. However, if a cobalt coating 4b is provided radially inwardly in addition to radially outwardly, the thermal mass of the heating element <NUM> may be increased, which can reduce the rate at which the heating element <NUM> is heatable by a given varying magnetic field in use.

In this embodiment, the heat resistant protective coating 4c is located radially outwards of the heat resistant support 4a and the cobalt coating 4b. That is, the heat resistant protective coating 4c is on an outer side of the cobalt coating 4b. Moreover, in this embodiment, a radially inward facing side of the heat resistant support 4a is free from a heat resistant protective coating 4c. However, in other embodiments, a heat resistant protective coating 4c may be provided radially inwards of the heat resistant support 4a in addition to, or alternatively to, radially outwards of the heat resistant support 4a. However, again, if a heat resistant protective coating 4c is provided radially inwardly in addition to radially outwardly, the thermal mass of the heating element <NUM> may be increased.

In some embodiments that are respective variations to the illustrated embodiments, the cobalt coating 2b, 3b, 4b is encapsulated. In some embodiments that are respective variations to the illustrated embodiments, the heat resistant protective coating 2c, 3c, 4c and the support 2a, 3a, 4a together encapsulate the cobalt coating 2b, 3b, 4b. In some other embodiments that are respective variations to the illustrated embodiments, the heat resistant protective coating 2c, 3c, 4c encapsulates the cobalt coating 2b, 3b, 4b and the support 2a, 3a, 4a.

<FIG> shows a schematic cross-sectional side view of an example of an article according to an embodiment of the invention. The article <NUM> is for use with apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material.

The article <NUM> comprises the heating element <NUM> of <FIG>, and aerosolisable material <NUM>. The aerosolisable material <NUM> may be any of the aerosolisable materials discussed herein, such as reconstituted aerosolisable material (e.g. reconstituted tobacco) or in the form of a gel. The article <NUM> may comprise a substrate, such as a paper, that is impregnated or coated with the aerosolisable material <NUM>, such as a gel. The aerosolisable material <NUM> may be cellulosic aerosolisable material.

The article <NUM> is substantially cylindrical with a substantially circular cross section, but in other embodiments the article <NUM> may have an oval or elliptical cross section or be other than cylindrical. In some embodiments, the article <NUM> may have a polygonal, quadrilateral, rectangular, square, triangular, star-shaped, or irregular cross section, for example. In this embodiment, the article <NUM> is a rod.

In this embodiment, the article <NUM> is elongate and has a longitudinal axis B-B. The longitudinal axis B-B of the article <NUM> is coincident with the longitudinal axis A-A of the heating element <NUM>. In other embodiments, the article <NUM> may not be elongate. In some such other embodiments, the article <NUM> still has an axial direction B-B that is perpendicular to the cross section of the article <NUM>.

The aerosolisable material <NUM> is in thermal contact with the heating element <NUM>. Accordingly, in use, heat generated in the heating element <NUM> is usable to heat the aerosolisable material <NUM> to volatilise at least one component of the aerosolisable material <NUM>. In some embodiments, the aerosolisable material <NUM> is in surface contact with the heating element <NUM>. Thus, heat may be conducted directly from the heating element to the aerosolisable material <NUM>. This can help to further increase the efficiency of heating of the aerosolisable material <NUM>. In other embodiments, the heating element <NUM> may be kept out of surface contact with the aerosolisable material <NUM>. For example, in some embodiments, a thermally-conductive barrier that is free from heating material and aerosolisable material may space the heating element <NUM> from the aerosolisable material <NUM>. In some embodiments, the thermally-conductive barrier may be a coating on the aerosolisable material <NUM> or on the heating element <NUM>. The provision of such a barrier may be advantageous to help to dissipate heat to alleviate hot spots in the heating element <NUM>.

The article <NUM> also comprises a wrapper <NUM> that is wrapped around the aerosolisable material <NUM>. The wrapper <NUM> encircles the aerosolisable material <NUM> and may help to protect the aerosolisable material <NUM> from damage during transport and use. During use, the wrapper <NUM> may also help to direct the flow of air into and through the aerosolisable material <NUM>, and may help to direct the flow of vapour or aerosol through and out of the aerosolisable material <NUM>.

In this embodiment, the wrapper <NUM> is wrapped around the aerosolisable material <NUM> so that free ends of the wrapper <NUM> overlap each other. The wrapper <NUM> may form all of, or a majority of, a circumferential outer surface of the article <NUM>. The wrapper <NUM> could be made of any suitable material, such as paper, card, reconstituted aerosolisable material (e.g. reconstituted tobacco), or heating material (e.g. a metal or metal alloy foil, such as aluminium foil). The wrapper <NUM> may also comprise an adhesive (not shown) that adheres the overlapped free ends of the wrapper <NUM> to each other. The adhesive may comprise one or more of, for example, gum Arabic, natural or synthetic resins, starches, and varnish. The adhesive helps prevent the overlapped free ends of the wrapper <NUM> from separating. In other embodiments, the adhesive may be omitted or the wrapper <NUM> may take a different from to that described. Any one of these types of wrapper may be applied to the other articles described or illustrated herein to form further embodiments. In some embodiments, the wrapped <NUM> may be omitted.

In some embodiments, the article <NUM> may comprise one or more further components. For example, the article <NUM> could comprise a filter for filtering aerosol or vapour released from the aerosolisable material <NUM> of the article <NUM> in use. The filter could be of any type used in the tobacco industry. For example, the filter may be made of cellulose acetate. The filter may be substantially cylindrical with a substantially circular cross section and a longitudinal axis. In other embodiments, the filter may have a different cross section, such as any of those discussed herein for articles, and/or be other than cylindrical, and/or not be elongate. In some embodiments, the filter abuts a longitudinal end of the aerosolisable material <NUM> and is axially aligned with the heating element <NUM>. In other embodiments, the filter may be spaced from the aerosolisable material <NUM>, such as by a gap and/or by one or more further components of the article <NUM>. Example further component(s) are an additive or flavour source (such as an additive- or flavour-containing capsule or thread), which may be held by a body of filtration material or between two bodies of filtration material, for example.

In some embodiments, the article <NUM> comprises a wrap that is wrapped around the aerosolisable material <NUM> and the filter (when provided) to retain the filter relative to the aerosolisable material <NUM>. The wrap may encircle the aerosolisable material <NUM> and the filter. During use, the wrap may also help to direct the flow of air into and through the aerosolisable material <NUM>, and may help to direct the flow of vapour or aerosol through and out of the aerosolisable material <NUM>. The wrap may be wrapped around the aerosolisable material <NUM> and the filter so that free ends of the wrap overlap each other. The wrap may form all of, or a majority of, a circumferential outer surface of the article <NUM>. The wrap could be made of any suitable material, such as paper, card, or reconstituted aerosolisable material (e.g. reconstituted tobacco). The wrap may also comprise an adhesive (not shown), such as one of those discussed elsewhere herein, that adheres the overlapped free ends of the wrap to each other. The adhesive helps prevent the overlapped free ends of the wrap from separating. In other embodiments, the adhesive may be omitted or the wrap may take a different from to that described. In other embodiments, the filter may be retained relative to the aerosolisable material <NUM> by a connector other than the wrap, such as an adhesive.

<FIG> shows a schematic cross-sectional side view of an example of another article according to an embodiment of the invention. The article <NUM> is for use with apparatus for heating aerosolisable material to volatilise at least one component of the aerosolisable material. The article <NUM> of <FIG> is the same as that of <FIG>, except that the article <NUM> has the heating element <NUM> of <FIG> in place of the heating element <NUM> of <FIG>. The article <NUM> is tubular with a hollow inner region defined by the hollow inner region 4d of the heating element <NUM>, and the wrapper <NUM> is wrapped around the aerosolisable material <NUM> and the heating element <NUM>. Any of the possible variations to the article <NUM> of <FIG> discussed herein may be made to the article <NUM> of <FIG> to form further embodiments. Moreover, in some embodiments, material, such as aerosolisable material, may be located in, or fill, the inner region 4d of the heating element <NUM>.

In some embodiments, the article <NUM>, <NUM> may be provided together with apparatus for heating the aerosolisable material <NUM>, <NUM> of the article <NUM>, <NUM> to volatilise at least one component of the aerosolisable material <NUM>, <NUM>. Together, the article <NUM>, <NUM> and the apparatus may be comprised in a system.

For example, <FIG> shows a schematic cross-sectional side view of an example of a system according to an embodiment of the invention. The system <NUM> comprises the article <NUM> of <FIG> and apparatus <NUM> for heating the aerosolisable material <NUM> of the article <NUM> to volatilise at least one component of the aerosolisable material <NUM>. In other embodiments, the article <NUM> may be replaced by any of the other articles described herein. In this embodiment, the apparatus <NUM> is a tobacco heating product (also known in the art as a tobacco heating device or a heat-not-burn device).

Broadly speaking, the apparatus <NUM> comprises a heating zone <NUM> for receiving the article <NUM>, and a device <NUM> for causing heating of the heating element <NUM> of the article <NUM> when the article <NUM> is in the heating zone <NUM>.

More specifically, the apparatus <NUM> of this embodiment comprises a body <NUM> and a mouthpiece <NUM>. The mouthpiece <NUM> may be made of any suitable material, such as a plastics material, cardboard, cellulose acetate, paper, metal, glass, ceramic, or rubber. The mouthpiece <NUM> defines a channel <NUM> therethrough. The mouthpiece <NUM> is locatable relative to the body <NUM> so as to cover an opening into the heating zone <NUM>. When the mouthpiece <NUM> is so located relative to the body <NUM>, the channel <NUM> of the mouthpiece <NUM> is in fluid communication with the heating zone <NUM>. In use, the channel <NUM> acts as a passageway for permitting volatilised material to pass from aerosolisable material of an article inserted in the heating zone <NUM> to an exterior of the apparatus <NUM>. In this embodiment, the mouthpiece <NUM> is releasably engageable with the body <NUM> so as to connect the mouthpiece <NUM> to the body <NUM>. In other embodiments, the mouthpiece <NUM> and the body <NUM> may be permanently connected, such as through a hinge or flexible member. In some embodiments, such as embodiments in which the article itself comprises a mouthpiece, the mouthpiece <NUM> of the apparatus <NUM> may be omitted.

The apparatus <NUM> may define an air inlet (not shown) that fluidly connects the heating zone <NUM> with the exterior of the apparatus <NUM>. Such an air inlet may be defined by the body <NUM> and/or by the mouthpiece <NUM>. A user may be able to inhale the volatilised component(s) of the aerosolisable material by drawing the volatilised component(s) through the channel <NUM> of the mouthpiece <NUM>. As the volatilised component(s) are removed from the article <NUM>, air may be drawn into the heating zone <NUM> via the air inlet of the apparatus <NUM>.

In this embodiment, the body <NUM> comprises the heating zone <NUM>. In this embodiment, the heating zone <NUM> comprises a recess <NUM> for receiving at least a portion of the article <NUM>. In other embodiments, the heating zone <NUM> may be other than a recess, such as a shelf, a surface, or a projection, and may require mechanical mating with the article in order to co-operate with, or receive, the article. In this embodiment, the heating zone <NUM> is elongate, and is sized and shaped to accommodate the whole article <NUM>. In other embodiments, the heating zone <NUM> may be other than elongate and/or dimensioned to receive only a portion of the article <NUM>.

In this embodiment, the device <NUM> comprises a magnetic field generator <NUM> for generating a varying magnetic field for penetrating the heating element <NUM> of the article <NUM> when the article <NUM> is in the heating zone <NUM>. However, in other embodiments, other forms of device <NUM> could be used.

In this embodiment, the magnetic field generator <NUM> comprises an electrical power source <NUM>, a coil <NUM>, a device <NUM> for passing a varying electrical current, such as an alternating current, through the coil <NUM>, a controller <NUM>, and a user interface <NUM> for user-operation of the controller <NUM>.

The electrical power source <NUM> of this embodiment is a rechargeable battery. In other embodiments, the electrical power source <NUM> may be other than a rechargeable battery, such as a non-rechargeable battery, a capacitor, a battery-capacitor hybrid, or a connection to a mains electricity supply.

The coil <NUM> may take any suitable form. In this embodiment, the coil <NUM> is a helical coil of electrically-conductive material, such as copper. In some embodiments, the magnetic field generator <NUM> may comprise a magnetically permeable core around which the coil <NUM> is wound. Such a magnetically permeable core concentrates the magnetic flux produced by the coil <NUM> in use and makes a more powerful magnetic field. The magnetically permeable core may be made of iron, for example. In some embodiments, the magnetically permeable core may extend only partially along the length of the coil <NUM>, so as to concentrate the magnetic flux only in certain regions. In some embodiments, the coil may be a flat coil. That is, the coil may be a two-dimensional spiral. In this embodiment, the coil <NUM> encircles the heating zone <NUM>. The coil <NUM> extends along a longitudinal axis that is substantially aligned with a longitudinal axis of the heating zone <NUM>. The aligned axes are coincident. In variations to this embodiment, the axes may be parallel, oblique or perpendicular to each other.

In this embodiment, the device <NUM> for passing a varying current through the coil <NUM> is electrically connected between the electrical power source <NUM> and the coil <NUM>. In this embodiment, the controller <NUM> also is electrically connected to the electrical power source <NUM>, and is communicatively connected to the device <NUM> to control the device <NUM>. More specifically, in this embodiment, the controller <NUM> is for controlling the device <NUM>, so as to control the supply of electrical power from the electrical power source <NUM> to the coil <NUM>. In this embodiment, the controller <NUM> comprises an integrated circuit (IC), such as an IC on a printed circuit board (PCB). In other embodiments, the controller <NUM> may take a different form. In some embodiments, the apparatus may have a single electrical or electronic component comprising the device <NUM> and the controller <NUM>. The controller <NUM> is operated in this embodiment by user-operation of the user interface <NUM>. In this embodiment, the user interface <NUM> is located at the exterior of the body <NUM>. The user interface <NUM> may comprise a push-button, a toggle switch, a dial, a touchscreen, or the like. In other embodiments, the user interface <NUM> may be remote and connected to the rest of the apparatus wirelessly, such as via Bluetooth.

In this embodiment, operation of the user interface <NUM> by a user causes the controller <NUM> to cause the device <NUM> to cause an alternating electrical current to pass through the coil <NUM>. This causes the coil <NUM> to generate an alternating magnetic field. The coil <NUM> and the heating zone <NUM> of the apparatus <NUM> are suitably relatively positioned so that, when the article <NUM> is located in the heating zone <NUM>, the varying magnetic field produced by the coil <NUM> penetrates the heating element <NUM> of the article <NUM>. As the cobalt of the cobalt coating 3b of the heating element <NUM> is an electrically-conductive material, this penetration causes the generation of one or more eddy currents in the cobalt coating 3b of the heating element <NUM>. The flow of eddy currents against the electrical resistance of the cobalt causes the cobalt coating 3b to be heated by Joule heating. As cobalt is ferromagnetic, the orientation of magnetic dipoles in the cobalt may change with the changing applied magnetic field, which causes heat to be generated in the cobalt coating 3b of the heating element <NUM>. The heat energy generated in the cobalt coating 3b passes to the aerosolisable material of the article <NUM>.

The apparatus <NUM> of this embodiment comprises a temperature sensor <NUM> for sensing a temperature of the heating zone <NUM>. The temperature sensor <NUM> is communicatively connected to the controller <NUM>, so that the controller <NUM> is able to monitor the temperature of the heating zone <NUM>. On the basis of one or more signals received from the temperature sensor <NUM>, the controller <NUM> may cause the device <NUM> to adjust a characteristic of the varying or alternating electrical current passed through the coil <NUM> as necessary, in order to ensure that the temperature of the heating zone <NUM> remains within a predetermined temperature range. The characteristic may be, for example, amplitude or frequency or duty cycle. Within the predetermined temperature range, in use the aerosolisable material within an article located in the heating zone <NUM> is heated sufficiently to volatilise at least one component of the aerosolisable material without combusting the aerosolisable material. Accordingly, the controller <NUM>, and the apparatus <NUM> as a whole, is arranged to heat the aerosolisable material to volatilise the at least one component of the aerosolisable material without combusting the aerosolisable material. In some embodiments, the temperature range is about <NUM> to about <NUM>, such as between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, or between about <NUM> and about <NUM>. In some embodiments, the temperature range is between about <NUM> and about <NUM>. In other embodiments, the temperature range may be other than this range. In some embodiments, the upper limit of the temperature range could be greater than <NUM>. In some embodiments, the temperature sensor <NUM> may be omitted. In some embodiments, the coating 3b of the heating element <NUM> may comprise an alloy of cobalt that has a Curie point temperature selected on the basis of the maximum temperature to which it is desired to heat the coating 3b, so that further heating above that temperature by induction heating the coating 3b is hindered or prevented.

<FIG> shows a schematic cross-sectional side view of an example of another system according to an embodiment of the invention. The system <NUM> comprises the article <NUM> of <FIG> and apparatus <NUM> for heating the aerosolisable material <NUM> of the article <NUM> to volatilise at least one component of the aerosolisable material <NUM>. In other embodiments, the article <NUM> may be replaced by any of the other articles described herein. Any of the herein-described possible variations to the apparatus of <FIG> may be made to the apparatus of <FIG> to form further embodiments of apparatus and/or further embodiments of a system.

In this embodiment, the apparatus <NUM> is the same as the apparatus <NUM> shown in <FIG> (and so like features are indicated with like reference numerals), except that the apparatus <NUM> of <FIG> comprises a support <NUM> that is locatable in the hollow inner region 4d of the article <NUM> to position the article <NUM> at a predetermined location in the heating zone <NUM> in use. This can help correctly position the heating element <NUM> of the article <NUM> relative to the coil <NUM> of the apparatus <NUM>. Operation of the apparatus <NUM> and its effect on the article <NUM> is otherwise substantially as described above and so will not be described again for conciseness.

<FIG> shows a schematic cross-sectional side view of an example of another system according to an embodiment of the invention. The system <NUM> comprises an article <NUM> comprising aerosolisable material. The system <NUM> also comprises apparatus <NUM> for heating the aerosolisable material of the article <NUM> to volatilise at least one component of the aerosolisable material. In other embodiments, the article <NUM> may be replaced by any of the other articles described herein. Any of the herein-described possible variations to the apparatus of <FIG> may be made to the apparatus of <FIG> to form further embodiments of apparatus and/or further embodiments of a system.

In this embodiment, the apparatus <NUM> is the same as the apparatus <NUM> shown in <FIG> (and so like features are indicated with like reference numerals), except that the apparatus <NUM> of <FIG> itself comprises a heating element <NUM> for heating the heating zone <NUM>. The heating element <NUM> projects into the heating zone <NUM>. The heating element <NUM> is the same as the heating element <NUM> of <FIG>, and so comprises a heat resistant support 3a, a coating 3b comprising cobalt located on the support 3a, and a heat resistant protective coating 3c arranged so that the cobalt coating 3b is located between the support 3a and the heat resistant protective coating 3c. Any of the herein-described possible variations to the heating element <NUM> of <FIG> may be made to the heating element <NUM> of the apparatus of <FIG> to form further embodiments of apparatus and/or further embodiments of a system. For example, in some embodiments, the heat resistant protective coating 3c may be omitted from the heating element <NUM> of the apparatus <NUM>. In some embodiments, the heating element of the apparatus <NUM> at least partially surrounds the heating zone <NUM> additionally or alternatively to projecting into the heating zone <NUM>.

<FIG> shows a schematic cross-sectional side view of an example of another system according to an embodiment of the invention. The system <NUM> comprises an article <NUM> comprising aerosolisable material. The system <NUM> also comprises apparatus <NUM> for heating the aerosolisable material of the article <NUM> to volatilise at least one component of the aerosolisable material. In other embodiments, the article <NUM> may be replaced by any of the other articles described herein. Any of the herein-described possible variations to the apparatus of <FIG> or <FIG> may be made to the apparatus of <FIG> to form further embodiments of apparatus and/or further embodiments of a system.

In this embodiment, the apparatus <NUM> is the same as the apparatus <NUM> shown in <FIG> (and so like features are indicated with like reference numerals), except that the heating element of the apparatus <NUM> of <FIG> is the same as the heating element <NUM> of <FIG>. The heating element <NUM> therefore comprises a heat resistant support 4a, a coating 4b comprising cobalt located on and radially outwards of the support 4a, and a heat resistant protective coating 4c arranged so that the cobalt coating 4b is located between the support 4a and the heat resistant protective coating 4c. Any of the herein-described possible variations to the heating element <NUM> of <FIG> may be made to the heating element <NUM> of the apparatus of <FIG> to form further embodiments of apparatus and/or further embodiments of a system. For example, in some embodiments, the heat resistant protective coating 4c may be omitted from the heating element <NUM> of the apparatus <NUM>.

In each of the systems <NUM>, <NUM> of <FIG>, the coil <NUM> and the heating element <NUM>, <NUM> of the apparatus <NUM>, <NUM> are suitably relatively positioned so that the varying magnetic field produced by the coil <NUM> penetrates the heating element <NUM>, <NUM> in use. As the cobalt of the cobalt coating 3b, 4b of the heating element <NUM>, <NUM> is an electrically-conductive material, this penetration causes the generation of one or more eddy currents in the cobalt coating 3b, 4b of the heating element <NUM>, <NUM>. The flow of eddy currents against the electrical resistance of the cobalt causes the heating element <NUM>, <NUM> to be heated by Joule heating. As cobalt is ferromagnetic, the orientation of magnetic dipoles in the cobalt may change with the changing applied magnetic field, which causes heat to be generated in the cobalt coating 3b, 4b of the heating element <NUM>, <NUM>.

In each of the systems <NUM>, <NUM> of <FIG>, the heating element <NUM>, <NUM> is locatable in the article <NUM>, <NUM> (such as in a pre-existing hollow region of the article <NUM>, <NUM>, or by displacing some of the aerosolisable material of the article <NUM>, <NUM>) when the article <NUM>, <NUM> is inserted into the heating zone <NUM>, so that the heat generated in the heating element <NUM>, <NUM> is efficiently passed by conduction (and/or possibly convection) to the aerosolisable material of the article <NUM>, <NUM> when the article <NUM>, <NUM> is located in the heating zone <NUM>. Operation of the apparatus <NUM>, <NUM> and its effect on the article <NUM>, <NUM> is otherwise substantially as described above and so will not be described again for conciseness.

In some embodiments, the article <NUM>, <NUM> of one of the systems <NUM>, <NUM> may include a heating element that is heatable by penetration with a varying magnetic field produced by the coil <NUM>. Accordingly, the aerosolisable material of the article <NUM>, <NUM> may be heated by one or both of the heating element of the article <NUM>, <NUM> and the heating element <NUM>, <NUM> of the apparatus <NUM>, <NUM>.

In some embodiments, the coating comprising cobalt consists only of cobalt. However, in other embodiments, in addition to cobalt, the coating may comprise one or more materials selected from the group consisting of: an electrically-conductive material, a magnetic material, and a magnetic electrically-conductive material. In some embodiments, the coating may comprise a cobalt alloy. In some embodiments, the coating comprising cobalt may also comprise one or more materials selected from the group consisting of: aluminium, gold, iron, nickel, conductive carbon, graphite, steel, plain-carbon steel, mild steel, stainless steel, ferritic stainless steel, copper, and bronze. Other heating material(s) in addition to cobalt may be used in other embodiments.

In some embodiments, the heating element is a free from holes or discontinuities. In some embodiments, the heating element comprises a foil. However, in some embodiments, the heating element may have holes or discontinuities. For example, in some embodiments, the heating element may comprise a mesh, a perforated sheet, or a perforated foil.

In some embodiments, the heating element comprises or consists of a stainless steel heat resistant support, a cobalt coating on the support, and a heat resistant protective coating comprising titanium nitride, the cobalt coating being located between the support and the heat resistant protective coating.

The cobalt coating may have a skin depth, which is an exterior zone within which most of an induced electrical current and/or induced reorientation of magnetic dipoles occurs. By providing that the cobalt coating has a relatively small thickness, a greater proportion of the cobalt coating may be heatable by a given varying magnetic field, as compared to heating material having a depth or thickness that is relatively large as compared to the other dimensions of the heating material. Thus, a more efficient use of material is achieved and, in turn, costs are reduced.

In some embodiments, the aerosolisable material comprises tobacco. However, in other embodiments, the aerosolisable material may consist of tobacco, may consist substantially entirely of tobacco, may comprise tobacco and aerosolisable material other than tobacco, may comprise aerosolisable material other than tobacco, or may be free from tobacco. In some embodiments, the aerosolisable material may comprise a vapour or aerosol forming agent or a humectant, such as glycerol, propylene glycol, triacetin, or diethylene glycol. In some embodiments, the aerosolisable material is non-liquid aerosolisable material, and the apparatus is for heating non-liquid aerosolisable material to volatilise at least one component of the aerosolisable material.

In some embodiments, the article <NUM>, <NUM>, <NUM> is a consumable article. Once all, or substantially all, of the volatilisable component(s) of the aerosolisable material in the article <NUM>, <NUM>, <NUM> has/have been spent, the user may remove the article <NUM>, <NUM>, <NUM> from the heating zone <NUM> of the apparatus <NUM>, <NUM>, <NUM>, <NUM> and dispose of the article <NUM>, <NUM>, <NUM>. The user may subsequently re-use the apparatus <NUM>, <NUM>, <NUM>, <NUM> with another of the articles <NUM>, <NUM>, <NUM>. However, in other respective embodiments, the article may be non-consumable, and the apparatus and the article may be disposed of together once the volatilisable component(s) of the aerosolisable material has/have been spent.

In some embodiments, the article <NUM>, <NUM>, <NUM> is sold, supplied or otherwise provided separately from the apparatus <NUM>, <NUM>, <NUM>, <NUM> with which the article <NUM>, <NUM>, <NUM> is usable. However, in some embodiments, the apparatus <NUM>, <NUM>, <NUM>, <NUM> and one or more of the articles <NUM>, <NUM>, <NUM> may be provided together as a system, such as a kit or an assembly, possibly with additional components, such as cleaning utensils.

Claim 1:
A heating element (<NUM>, <NUM>, <NUM>, <NUM>) for use in heating aerosolisable material (<NUM>, <NUM>) to volatilise at least one component of the aerosolisable material, wherein the heating element comprises a heat resistant support (1a, 2a, 3a, 4a) and a coating on the support (1b, 2b, 3b, 4b); characterized in that the coating comprises cobalt and the support comprises one or more materials selected from the group consisting of: a metal and a metal alloy.