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> discloses a smoking article incorporating foamed tobacco materials, and discloses a smoking article incorporating a cartridge containing tobacco and an aerosol-forming material.

<CIT> discloses a smoking article having a flavour unit comprising an electrical heater, tobacco flavor material and a fibrous mat used as a carrier for the tobacco flavor material. This document also discloses tobacco flavor material being a foam.

<CIT> discloses a flavour generating article having a disposable filter/flavor portion or cartridge. The cartridge comprises a flavour segment being a cylindrical portion of an extruded open-cell foamed tobacco product.

<CIT> discloses a foamed product extruded in the shape of a solid rod as an intermediate product in the fabrication of a foamed, extruded, tobacco-containing smoking article.

<CIT> discloses a cigarette having a tobacco web comprising a layer of tobacco flavor material which may include a foam.

<CIT> discloses cigarettes comprising filler material contained in a wrapping material, including low density filler material provided by employing foamed reconstituted tobacco.

<CIT> discloses an aerosol-generating article comprising a blade-shaped susceptor within an aerosol-forming substrate comprising a gathered sheet of crimped homogenised tobacco material. This document also discloses a solid aerosol-forming substrate provided on or embedded in a thermally stable carrier, wherein the carrier may take the form of powder, granules, pellets, shreds, strands, strips or sheets, and the solid aerosol-forming substrate may be deposited on the surface of the carrier in the form of, for example, a sheet, foam, gel or slurry.

<CIT> discloses a cartridge for an electronic vapour inhaler, having an elongate induction heatable element an a flavour-release medium adhered to the surface of the elongate induction heatable element. This document also discloses a cartridge for an electronic vapour inhaler, with particulate induction heatable material dispersed throughout a flavour-release medium.

<CIT> discloses an aerosol-forming substrate having a solid material which is capable of releasing volatile compounds that can form an aerosol upon heating of the aerosol-forming substrate, and a first and second susceptor materials for heating the aerosol-forming substrate.

<CIT>, forming part of the prior art under Art. <NUM>(<NUM>) EPC, shows an aerosol-forming article with a hybrid aerosol-forming element comprising a tobacco plug of a solid aerosol-forming substrate material comprising a gathered sheet of crimped homogenised tobacco material, a susceptor blade located along a radially central axis of the aerosol-forming element, and a liquid retention material tube arranged around the tobacco plug and adapted to retain an amount of aerosol-forming liquid. The liquid in the retention material may leave the retention material only into the direction of the aerosol plug.

<CIT>, forming part of the prior art under Art. <NUM>(<NUM>) EPC, discloses a capsule containing aerosol-forming substrate. The shell of the capsule or the entire capsule may be made from a susceptor material capable of being inductively heated such as to heat and vaporize the aerosol-forming substrate in the capsule. This document also discloses a capsule with a high liquid retention material, which may be a sponge material, to substantially prevent leakage of a liquid aerosol-forming substrate.

According to the invention, there is provided an article according to claim <NUM> and a system according to claim <NUM>. The dependent claims <NUM>-<NUM> and <NUM> define embodiments of the invention as claimed. The following aspects and embodiments of the disclosure need not fall within the scope of the claims, but may contain features present in embodiments of the invention as claimed.

A first aspect of the present disclosure provides an article for use with apparatus for heating smokable material to volatilise at least one component of the smokable material, the article including a foam comprising smokable material.

In an exemplary embodiment, the foam comprises gas dispersed in a solid medium.

In an exemplary embodiment, the solid medium comprises the smokable material.

In an exemplary embodiment, the solid medium comprises a carrier.

In an exemplary embodiment, the carrier comprises cellulose or starch, such as starch-lignin.

In an exemplary embodiment, the foam is an open-cell foam.

In an exemplary embodiment, the foam extends from one end of the article to an opposite end of the article.

In an exemplary embodiment, a first portion of the foam has a first density, a second portion of the foam has a second density, and the second density is greater than the first density.

In an exemplary embodiment, the article is elongate, and the first and second portions of the foam are located at different positions along a length of the article.

In an exemplary embodiment, the article further comprises heating material that is heatable by penetration with a varying magnetic field, and the heating material is in thermal contact with the smokable material.

In an exemplary embodiment, the foam is fixed or adhered to the heating material.

In an exemplary embodiment, the heating material is in the form of a body that extends from one end of the article to an opposite end of the article.

In an exemplary embodiment, the heating material comprises one or more materials selected from the group consisting of: an electrically-conductive material, a magnetic material, and a magnetic electrically-conductive material.

In an exemplary embodiment, the heating material comprises a metal or a metal alloy.

In an exemplary embodiment, the heating material comprises one or more materials selected from the group consisting of: aluminium, gold, iron, nickel, cobalt, conductive carbon, graphite, plain-carbon steel, stainless steel, ferritic stainless steel, copper, and bronze.

In an exemplary embodiment, the article comprises elements disbursed through the foam, each of the elements comprises heating material that is heatable by penetration with a varying magnetic field, and the heating material is in thermal contact with the smokable material.

In an exemplary embodiment, the elements are disbursed evenly, or substantially evenly, through the foam.

In an exemplary embodiment, each of the elements comprises a closed circuit of the heating material.

In an exemplary embodiment, the article is free from heating material that is heatable by penetration with a varying magnetic field.

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

A second aspect of the present disclosure provides a system, comprising: an article including a foam comprising smokable material; and apparatus for heating the smokable material to volatilise at least one component of the smokable material, wherein the apparatus comprises a heating zone for receiving at least a portion of the article.

In an exemplary embodiment, the apparatus is for heating the smokable material to volatilise at least one component of the smokable material without combusting the smokable material.

In an exemplary embodiment, the article of the system of the second aspect is the article of the first aspect. The article of the system of the second aspect may have any one or more of the features discussed above as being present in respective exemplary embodiments of the article of the first aspect.

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

As used herein, the term "foam" includes substances comprising gas dispersed in a liquid medium or in a solid medium. In some embodiments, the foam comprises a gas dispersed in a solid medium, and the solid medium comprises the smokable material. In some embodiments, the solid medium consists of, or consists substantially entirely of, the smokable material. The foam may be an open-cell foam, a closed-cell foam, or a foam comprising both open and closed cells. In some embodiments, an open-cell foam may allow fluid flow through the foam to pick up volatilised components of the smokable material in use. In some embodiments, a closed-cell foam may be porous to allow fluid flow through the foam to pick up volatilised components of the smokable material in use. In some embodiments, the foam may be a closed-cell foam that becomes an open-cell foam upon heating.

In some embodiments, the solid medium comprises a carrier, which may for example be cellulose or starch, such as starch-lignin. The smokable material may be mixed with the carrier. In some embodiments, the solid material may be thermally conductive to promote heat transfer. In some embodiments, as discussed below, the solid material may comprise heating material that is heatable by penetration with a varying magnetic field.

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 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 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.

Referring to <FIG> there is shown a schematic perspective view of an example of an article, not according to the invention as claimed. The article <NUM> comprises a foam <NUM> that comprises smokable material. The article <NUM> is for use with apparatus for heating the smokable material to volatilise at least one component of the smokable material without burning the smokable material, such as the apparatus <NUM> shown in <FIG> and described below.

In this embodiment, the foam <NUM> is in the form of a cylindrical rod. The rod has a substantially circular cross-section. The foam extends from one end of the article <NUM> to an opposite end of the article. Thus, in use, air may be drawn into the foam <NUM> at one end of the article <NUM>, the air may pass through the foam <NUM> and pick up volatilised components released from the smokable material, and then the volatilised components, typically in the form of vapour or an aerosol, may be drawn out of the foam <NUM> at the opposite end of the article <NUM>. In this embodiment in which the article <NUM> is elongate, these ends of the article <NUM> between which the foam <NUM> extends are opposite longitudinal ends of the article <NUM>. However, in other embodiments, the ends may be any two ends or sides of the article, such as any two opposite ends or sides of the article.

The foam <NUM> comprises gas dispersed in a solid medium. That is, walls of cells of the foam <NUM> are made of a solid as opposed to, say, a liquid. The solid medium comprises a carrier and the smokable material. The carrier comprises cellulose or starch, but in other embodiments other materials may be used. In this embodiment, the gas is air, but in other embodiments one or more other gases could be used, such as oxygen.

In the article <NUM> of this embodiment, the foam <NUM> is an open-cell foam. The use of an open-cell foam facilitates the flow of air drawn into the foam <NUM> and through the foam <NUM> by a user. Moreover, when the smokable material is heated in use, the open-cell nature of the foam <NUM> facilitates the flow of volatilised components released from the smokable material, typically in the form of vapour or an aerosol, through and out of the foam <NUM> as drawn by a user.

In this embodiment, the foam <NUM> has a density of about <NUM>/m<NUM>, although in other embodiments the density may be a density less than <NUM>/m<NUM>, such as a density of between <NUM>/m<NUM> and <NUM>/m<NUM>. The density of the foam <NUM> may be chosen to help deliver desired levels of thermal conductivity of the foam <NUM>, and/or water retention of the foam <NUM>, and/or ease of fluid flow through the foam <NUM> in use.

The article <NUM> of this embodiment has a cover <NUM> around the foam <NUM>. The cover <NUM> helps to protect the foam <NUM> from damage during transport and use of the article <NUM>. During use, the cover <NUM> may also help to direct the flow of air into and through the foam <NUM>, and help to direct the flow of vapour or aerosol through and out of the foam <NUM>.

In this embodiment, the cover <NUM> comprises a wrapper <NUM> that is wrapped around the foam <NUM> so that free ends of the wrapper <NUM> overlap each other. The wrapper <NUM> thus forms all of, or a majority of, a circumferential outer surface of the article <NUM>. The wrapper <NUM> may be formed from paper, reconstituted smokable material, such as reconstituted tobacco, or the like. The cover <NUM> of this embodiment also comprises an adhesive <NUM> 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 <NUM> helps prevent the overlapped free ends of the wrapper <NUM> from separating. It is to be noted that the size of the adhesive <NUM> relative to the wrapper <NUM> is accentuated in <FIG> for clarity.

The cover <NUM> defines an outer surface of the article <NUM> and may contact the apparatus in use. In this embodiment, the article <NUM> is elongate and cylindrical with a substantially circular cross-section. However, in other embodiments, the article may have a cross-section other than circular and/or not be elongate and/or not be cylindrical. In this embodiment, the article <NUM> has proportions approximating those of a cigarette. The cover <NUM> may be made of a thermally-conductive material, for transferring heat energy from the apparatus to the foam <NUM> in use.

Referring to <FIG> there are shown a schematic perspective view and a schematic cross-sectional view of an example of another article according to an embodiment of the invention as claimed.

The article <NUM> of <FIG> is free from heating material that is heatable by penetration with a varying magnetic field. The article <NUM> of <FIG> is identical to the article <NUM> of <FIG>, except that the article <NUM> of <FIG> comprises such heating material. Therefore, in the interests of conciseness features common to the two embodiments will not be described again in detail. The article <NUM> is for use with apparatus for heating the smokable material to volatilise at least one component of the smokable material without burning the smokable material, such as the apparatus <NUM> shown in <FIG> and described below. Any of the herein-described possible variations to the article <NUM> of <FIG> may be made to the article <NUM> of <FIG> to form separate respective embodiments.

In this embodiment, in addition to the cover <NUM> and the foam <NUM>, the article <NUM> comprises heating material that is heatable by penetration with a varying magnetic field. The heating material is in thermal contact with the smokable material. Therefore, the heating material is heatable in use to heat the smokable material. More specifically, the article <NUM> comprises elements <NUM> disbursed through the foam <NUM>, and each of the elements <NUM> comprises the heating material. The elements <NUM> are disbursed evenly, or substantially evenly, through the foam <NUM>. This substantially even distribution helps to provide substantially even heating of the smokable material in use. In other embodiments, the elements <NUM> may instead be disbursed through the foam <NUM> unevenly so that a first region of the article has a greater density or proportion of heating material than a second region. Such uneven distribution of the elements <NUM> could help provide progressive heating of the smokable material in use, as the smokable material in the first region may be heated more quickly than the second region, so that the first region releases volatilised components before the second region. The first region may also reach a higher maximum temperature than the second region in use.

In this embodiment, each of the elements <NUM> comprises a closed circuit of the heating material. More specifically, each of the elements <NUM> is loop-shaped. Yet more specifically, in this embodiment, each of the elements <NUM> is ring-shaped. A loop-shaped element may be of any shape that defines a path that starts and ends at the same point so as to create a closed circuit, whereas a ring-shaped element necessarily is circular or substantially circular. A ring shaped element has a relatively a large surface area to weight ratio, which can help to avoid the elements <NUM> tending to cluster by settling due to gravity. A ring shaped element can have a small cross-sectional area to diameter ratio. Therefore, the circulating current in the ring when subjected to a varying magnetic field may penetrate most or all of the ring, rather than be confined to just a "skin" thereof, as can be the case when a susceptor has too great a thickness. Thus, a more efficient use of material is achieved and, in turn, costs are reduced. In this embodiment, each of the elements <NUM> consists entirely, or substantially entirely, of the heating material. However, in other embodiments, one or more of the elements <NUM> may comprise a loop- or ring-shaped body that is free from heating material and that carries the closed circuit of heating material. For example, one or more of the elements may comprise a ring-shaped body free from heating material with a closed-circuit of the heating material coated thereon.

In variations to this embodiment, some or each of the elements <NUM> may be irregularly-shaped, spherical, a particle, or a discrete strand. When discrete strands of the heating material are provided, the strands may overlap and/or contact one another to define one or more closed circuits of the heating material. The strands may all be made of the same heating material. The strands may be linear or curved, for example, such as helical. In some embodiments, as mentioned above, each of the elements <NUM> may comprise a body that is free from heating material and that carries heating material. The heating material carried by the body may be in the form of a closed circuit.

In variations to the illustrated embodiment, the heating material may not form closed circuits. That is, the elements <NUM> may be free from closed circuits of heating material.

In some embodiments, the elements <NUM> may comprise elements of a first material and elements of a second material that is different from the first material. The first and second materials may be heatable by a given varying magnetic field at different rates.

The article <NUM> of <FIG> is identical to the article <NUM> described above with reference to <FIG>, except that the article <NUM> comprises heating material that is heatable by penetration with a varying magnetic field. Therefore, in the interests of conciseness features common to the two embodiments will not be described again in detail. The article <NUM> is for use with apparatus for heating the smokable material to volatilise at least one component of the smokable material without burning the smokable material, such as the apparatus <NUM> shown in <FIG> and described below. Any of the herein-described possible variations to the article <NUM> of <FIG> may be made to the article <NUM> of <FIG> to form separate respective embodiments.

In this embodiment, in addition to the cover <NUM> and the foam <NUM>, the article <NUM> comprises heating material that is heatable by penetration with a varying magnetic field. More specifically, the article <NUM> comprises a body of the heating material <NUM> within the foam <NUM>. The heating material is in thermal contact with the smokable material. Therefore, the heating material is heatable in use to heat the smokable material. In this embodiment, the foam <NUM> is fixed to the heating material of the body <NUM>. This is achieved by adhering the foam <NUM> to the body <NUM>. However, in other embodiments, the fixing may be by other than adhesion. In some embodiments the foam <NUM> may not be fixed to the heating material as such.

In this embodiment, the body of heating material <NUM> is elongate and extends from one end of the foam <NUM> to an opposite end of the foam <NUM>. This can help to provide more uniform heating of the smokable material of the foam <NUM> in use. However, in other embodiments, the body of heating material <NUM> may not extend to either of the opposite ends of the foam <NUM>, or may extend to only one of the ends of the foam <NUM> and be spaced from the other of the ends of the foam <NUM>.

In this embodiment, the body of heating material <NUM> extends from one end of the article <NUM> to an opposite end of the article <NUM>. This can aid manufacturing of the article <NUM>. However, in other embodiments, the body of heating material <NUM> may not extend to either of the opposite ends of the article <NUM>, or may extend to only one of the ends of the article <NUM> and be spaced from the other of the ends of the article <NUM>.

In this embodiment, the body of heating material <NUM> extends along a longitudinal axis that is substantially aligned with a longitudinal axis of the article <NUM>. This can aid manufacturing of the article <NUM>. In this embodiment, the aligned axes are coincident. In a variation to this embodiment, the aligned axes may be parallel to each other. However, in other embodiments, the axes may be oblique to each other.

In this embodiment, the body of heating material <NUM> is encircled by the foam <NUM>. That is, the foam <NUM> extends around the body of heating material <NUM>. In embodiments in which the body of heating material <NUM> does not extend to either of the opposite ends of the foam <NUM>, the foam <NUM> may extend around the body of heating material <NUM> and also cover the ends of the body of heating material <NUM>, so that the body of heating material <NUM> is surrounded by the foam <NUM>.

In this embodiment, the body <NUM> is impermeable to air or volatilised material, and is substantially free from discontinuities. The body <NUM> may thus be relatively easy to manufacture. However, in variations to this embodiment, the body <NUM> may be permeable to air and/or permeable to volatilised material created when the smokable material is heated. Such a permeable nature of the body <NUM> may help air passing through the article <NUM> to pick up the volatilised material created when the smokable material is heated.

In this embodiment, the body of heating material <NUM> has a rectangular, or substantially rectangular, cross-section perpendicular to its length. The body of heating material <NUM> has two opposing major surfaces joined by two minor surfaces. Therefore, the depth or thickness of the body <NUM> is relatively small as compared to the other dimensions of the body <NUM>. However, in other embodiments, the body <NUM> may have a cross-section that is a shape other than rectangular, such as circular, elliptical, annular, polygonal, square, triangular, X-shaped, T-shaped, star-shaped, or radially-finned.

In this embodiment, the cross-section of the body of heating material <NUM> is constant along the length of the body <NUM>. Moreover, in this embodiment, the body of heating material <NUM> is planar, or substantially planar. The body of heating material <NUM> of this embodiment can be considered a flat strip or ribbon. However, in other embodiments, this may not be the case.

In some embodiments, the body of heating material <NUM> may be non-planar. For example, the body <NUM> may follow a wavelike or wavy path, be twisted, be corrugated, be helical, have a spiral shape, comprise a plate or strip or ribbon having protrusions thereon and/or indentations therein, comprise a mesh, comprise expanded metal, or have a non-uniform non-planar shape. Such non-planar shapes may help air passing through the article to pick up the volatilised material created when the smokable material is heated. Non-planar shapes can provide a tortuous path for air to follow, creating turbulence in the air and causing better heat transfer from the heating material to the smokable material. The non-planar shapes can also increase the surface area of the body of heating material <NUM> per unit length of the body <NUM>. This can result in greater or improved Joule heating of the body <NUM>, and thus greater or improved heating of the smokable material. In some embodiments, the body of heating material <NUM> may be hollow or perforated.

Referring to <FIG> there are shown schematic cross-sectional views of examples of other articles according to respective embodiments of the disclosure. The article <NUM> of <FIG>, not according to the invention as claimed, is identical to the article <NUM> described above with reference to <FIG>, except for the form of the foam <NUM> of the article <NUM>. The article <NUM> of <FIG>, according to the invention as claimed, is identical to the article <NUM> described above with reference to <FIG>, except for the form of the foam <NUM> of the article <NUM>. The article <NUM> of <FIG>, according to the invention as claimed, is identical to the article <NUM> described above with reference to <FIG>, except for the form of the foam <NUM> of the article <NUM>. In the interests of conciseness, features common to two embodiments will not be described again in detail. Each of the articles <NUM>, <NUM>, <NUM> is for use with apparatus for heating the smokable material to volatilise at least one component of the smokable material without burning the smokable material, such as the apparatus <NUM> shown in <FIG> and described below.

Any of the herein-described possible variations to the article <NUM> of <FIG> may be made to the article <NUM> of <FIG> to form separate respective embodiments. Similarly, any of the herein-described possible variations to the article <NUM> of <FIG> may be made to the article <NUM> of <FIG> to form separate respective embodiments, and any of the herein-described possible variations to the article <NUM> of <FIG> may be made to the article <NUM> of <FIG> to form separate respective embodiments.

In each of the articles <NUM>, <NUM>, <NUM> of <FIG>, a first portion 20a of the foam <NUM> has a first density and a second portion 20b of the foam <NUM> has a second density. In these embodiments the second density is greater than the first density, but in respective variations to these embodiments the first density may be greater than the second density. As will be appreciated from consideration of the Figures, the first and second portions 20a, 20b of the foam <NUM> are located at different positions along the length of the elongate articles <NUM>, <NUM>, <NUM>. Therefore, in use, vapour or aerosol flows from one of the first and second portion 20a, 20b of the foam <NUM> to and through the other of the first and second portions 20a, 20b of the foam <NUM>. The first and second portions 20a, 20b of the foam <NUM> may be held together by the cover <NUM>.

Providing the first and second portions 20a, 20b of the foam <NUM> with different respective densities may help to determine or affect different relative characteristics of the first and second portions 20a, 20b of the foam <NUM>, such as their relative strengths, their relative masses, their relative thermal conductivities, their relative resistances to airflow, the relative amounts of smokable material they contain, and their relative rates of releasing volatilised components of the smokable material in use. The densities may also help determine or affect the centre of mass of the article.

Foams that have different densities but are otherwise identical may heat at different rates in use. Therefore, by providing the first and second portions 20a, 20b of foam <NUM> with different densities, progressive heating of the article <NUM> by heating of the heating material may be provided.

In the embodiment of <FIG>, the elements <NUM> comprising heatable material are disbursed evenly, or substantially evenly, through all the foam <NUM>. Alternatively, in other embodiments, the density of distribution of the elements <NUM> in the first portion 20a of the foam <NUM> may differ to that in the second portion 20b of the foam <NUM>. For example, there may be less dense distribution of the elements <NUM> in the first portion 20a of the foam <NUM> than in the second portion 20b of the foam <NUM>, or there may be less dense distribution of the elements <NUM> in the second portion 20b of the foam <NUM> than in the first portion 20a of the foam <NUM>.

In variations to the embodiment of <FIG>, the density of the foam <NUM> could instead vary with distance from the body of heating material <NUM>, or could vary with both distance from and distance along the body of heating material <NUM>. This may help to tailor the release of aerosol as the article is heated in use. For example, the first and second portions of the foam <NUM> may be arranged with the relatively denser portion of foam closer to the body of heating material <NUM> than the less dense portion of foam. Alternatively, the less dense portion of foam may be closer to the body of heating material <NUM> than the relatively denser portion of the foam. For example, in some embodiments, one of the first and second portions of foam may be tubular and encircling the body of heating material <NUM>, and the other of the first and second portions of foam may be tubular and encircling the other of the first and second portions of foam.

In each of the embodiments discussed above that comprises heating material, the heating material is steel. However, in other embodiments, the heating material 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 heating material may comprise a metal or a metal alloy. In some embodiments, the heating material may comprise one or more materials selected from the group consisting of: aluminium, gold, iron, nickel, cobalt, conductive carbon, graphite, plain-carbon steel, stainless steel, ferritic stainless steel, copper, and bronze. Other heating material(s) may be used in other embodiments. It has been found that, when magnetic electrically-conductive material is used as the heating material, magnetic coupling between the magnetic electrically-conductive material and an electromagnet of the apparatus in use may be enhanced. In addition to potentially enabling magnetic hysteresis heating, this can result in greater or improved Joule heating of the heating material, and thus greater or improved heating of the smokable material.

In each of the articles <NUM>, <NUM>, <NUM>, <NUM> shown in <FIG>, the heating material is in surface contact with the smokable material. Thus, when the heating material is heated by penetration with a varying magnetic field, heat may be transferred directly from the heating material to the smokable material. In other embodiments, the heating material may be kept out of surface contact with the smokable material. For example, in some embodiments, the article <NUM>, <NUM>, <NUM>, <NUM> may comprise a thermally-conductive barrier that is free from heating material and that spaces the heating material from the smokable material. In some embodiments, the thermally-conductive barrier may be a coating on the heating material. The provision of such a barrier may be advantageous to help to dissipate heat to alleviate hot spots in the heating material.

The heating material 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 heating material has a relatively small thickness, a greater proportion of the heating material 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.

The use of a foam may help to provide a large surface area from which volatilised components of the smokable material may be picked up by fluid flow through the foam in use. The use of a foam may, for example, enhance thermal conductivity in the article as compared, say, to a cut-rag smokable material rod. In turn, this may help provide faster and/or more even heating of the smokable material, or the article as a whole. The use of a foam and the characteristics of the foam may also help to determine the strength of the article, the thermal conductivity of the article, and the resistance to airflow through the article.

The foam may comprise smokable material, a binder (such as sodium alginate), a foam enhancer (such as hydroxypropyl cellulose (HPC)), and an aerosol forming agent (such as glycerol, propylene glycol, triacetin, or diethylene glycol).

In some embodiments, the foam may be manufactured by hydrating a material (such as an alginate, e.g. sodium alginate) to form a paste. An aerosol forming agent and smokable material (such as in the form of ground smokable material) may be added to the paste. A foam enhancer (such as hydroxypropyl cellulose (HPC)) may be added, which may help to trap a gas (such as air) to form a foam. A citrate (such as sodium citrate or calcium citrate) may be added to help retain the structure of the foam.

In some embodiments, the foam may be made as a sheet, and then rolled or coiled for use in an article embodying the invention. Alternatively, the foam may be made as a sheet, and then a portion of the foam for use in an article embodying the invention may be punched or cut from the sheet. Alternatively, the foam may be made as a sheet, and then shredded for use in an article embodying the invention. The formed shreds of foam may be combined to form a rod.

In some embodiments, the foam may be made from a sheet material (comprising smokable material) that is manufactured using a bandcast process. This process itself gives the sheet material some porosity. In order to increase the fill value of the sheet material, foaming may be introduced to increase structural voids at a reduced density. It is possible to tailor the porosity, density, and pore size of the sheet material accordingly. Activated carbon may be incorporated into the sheet material, for example in an amount of <NUM> to <NUM>% (such as wt%). It has been found that a significant portion of the carbon's microstructure may be maintained and not covered by the sheet making process.

In some embodiments, the foam may comprise reconstituted smokable material, such as reconstituted tobacco. During manufacture of reconstituted smokable material, there is flexibility to introduce ingredient(s) that could enhance foaming, such as during separate processing of a base web/fibre and a liquid extract.

The above two processes may be usable to form sheet material that is pliable, yet has sufficiently low density and high firmness to allow good pressure drop, and thus good aerosol flow through the material in use.

In some embodiments, the smokable material may be applied as an extract to a foam substrate. The foam substrate may be foamed reconstituted smokable material or foamed inert material. The inert material may be free from smokable material.

Each of the above-described articles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and described variants thereof may be used with an apparatus for heating the smokable material to volatilise at least one component of the smokable material. The apparatus may be to heat the smokable material to volatilise the at least one component of the smokable material without burning the smokable material. Any one of the article(s) <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and such apparatus may be provided together as a system. The system may take the form of a kit, in which the article <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is separate from the apparatus. Alternatively, the system may take the form of an assembly, in which the article <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is combined with the apparatus. An example system will now be described with reference to <FIG>.

Referring to <FIG> there is shown a schematic cross-sectional view of an example of a system according to an embodiment of the disclosure, The system <NUM> of this embodiment comprises an article <NUM> comprising a foam comprising smokable material, and apparatus <NUM> for heating the smokable material of the article <NUM> to volatilise at least one component of the smokable material. In this embodiment, not according to the invention as claimed, the article <NUM> of the system <NUM> is the article <NUM> of <FIG>. However, in other embodiments, the article of the system <NUM> may be an article other than the article <NUM> of <FIG>, such as one of the articles <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of <FIG>, <FIG>, wherein the system is according to the invention as claimed if the article is one of the articles <NUM>, <NUM>, <NUM> and <NUM>, and is not according to the invention as claimed if the article is article <NUM>. Broadly speaking, the apparatus <NUM> comprises a heating zone <NUM> for receiving at least a portion of the article <NUM>. In this embodiment, the apparatus <NUM> comprises a heater <NUM> for heating the heating zone <NUM>, wherein the heater <NUM> comprises heating material that is heatable by penetration with a varying magnetic field; and a magnetic field generator <NUM> for generating a varying magnetic field that penetrates the heating material of the heater <NUM>.

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 an article inserted in the heating zone <NUM> to an exterior of the apparatus <NUM>. In this embodiment, the mouthpiece <NUM> of the apparatus <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 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> of the apparatus <NUM> and/or by the mouthpiece <NUM> of the apparatus <NUM>. A user may be able to inhale the volatilised component(s) of the smokable 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, 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 <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> in order to co-operate with, or receive, the article <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. In this embodiment, the heating zone <NUM> is elongate, and is sized and shaped to receive the article <NUM>. In this embodiment, the heating zone <NUM> accommodates the whole article <NUM>. In other embodiments, the heating zone <NUM> may be dimensioned to receive only a portion of the article <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

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>.

In this embodiment, the electrical power source <NUM> 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> is in a fixed position relative to the heater <NUM> and the heating zone <NUM>. In this embodiment, the coil <NUM> encircles the heater <NUM> and the heating zone <NUM>. In this embodiment, the coil <NUM> extends along a longitudinal axis that is substantially aligned with a longitudinal axis A-A of the heating zone <NUM>. In this embodiment, the aligned axes are coincident. In a variation to this embodiment, the aligned axes may be parallel to each other. However, in other embodiments, the axes may be oblique to each other. Moreover, in this embodiment, the coil <NUM> extends along a longitudinal axis that is substantially coincident with a longitudinal axis of the heater <NUM>. This can help to provide more uniform heating of the heater <NUM> in use, and can also aid manufacturability of the apparatus <NUM>. In other embodiments, the longitudinal axes of the coil <NUM> and the heater <NUM> may be aligned with each other by being parallel to each other, or may be oblique 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>, so as to cause the coil <NUM> to generate an alternating magnetic field. The coil <NUM> and the heater <NUM> of the apparatus <NUM> are suitably relatively positioned so that the alternating magnetic field produced by the coil <NUM> penetrates the heating material of the heater <NUM>. When the heating material of the heater <NUM> is an electrically-conductive material, this may cause the generation of one or more eddy currents in the heating material. The flow of eddy currents in the heating material against the electrical resistance of the heating material causes the heating material to be heated by Joule heating. In this embodiment, the heating material is made of a magnetic material, and so the orientation of magnetic dipoles in the heating material changes with the changing applied magnetic field, which causes heat to be generated in the heating material.

The heater <NUM> outputs substantially the same amount of heat at each position along its length. Therefore, the foam <NUM> of the article <NUM> is substantially uniformly heated along its length. As the densities of the first and second portions 20a of the foam <NUM> differ from each other, one of the first and second portions 20a, 20b of the foam <NUM> may be heated before the other in use. For example, the denser portion of the foam <NUM> may heat quicker than the less dense portion of the foam.

In this embodiment, an impedance of the coil <NUM> of the magnetic field generator <NUM> is equal, or substantially equal, to an impedance of the heater <NUM>. If the impedance of the heater <NUM> were instead lower than the impedance of the coil <NUM>, then the voltage generated across the heater <NUM> in use may be lower than the voltage that may be generated across the heater <NUM> when the impedances are matched. Alternatively, if the impedance of the heater <NUM> were instead higher than the impedance of the coil <NUM>, then the electrical current generated in the heater <NUM> in use may be lower than the current that may be generated in the heater <NUM> when the impedances are matched. In embodiments of the system <NUM> comprising one of the articles <NUM>, <NUM>, of <FIG>, similarly the impedance of the coil <NUM> may be equal, or substantially equal, to an impedance of the part of the article <NUM>, <NUM>, <NUM>, <NUM> comprising heating material. Matching the impedances may help to balance the voltage and current to maximise the heating power generated at the heater <NUM> or heating material of the article <NUM>, <NUM>, <NUM>, <NUM> when heated in use. In some embodiments, the impedance of the device <NUM> may be equal, or substantially equal, to a combined impedance of the coil <NUM> and the heater <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 smokable material within an article <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> located in the heating zone <NUM> is heated sufficiently to volatilise at least one component of the smokable material without combusting the smokable material. Accordingly, the controller <NUM>, and the apparatus <NUM> as a whole, is arranged to heat the smokable material to volatilise the at least one component of the smokable material without combusting the smokable 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 heating material may have a Curie point temperature selected on the basis of the maximum temperature to which it is desired to heat the heating material, so that further heating above that temperature by induction heating the heating material is hindered or prevented.

In an embodiment that is a variation to the system <NUM> shown in <FIG>, the coil <NUM> may be arranged to generate an alternating or otherwise varying magnetic field that penetrates heating material of the article <NUM>, <NUM>, <NUM>, <NUM> when the apparatus <NUM> and the article <NUM>, <NUM>, <NUM>, <NUM> are suitably relatively positioned with the article <NUM>, <NUM>, <NUM>, <NUM> in the heating zone <NUM>. When the heating material of the article <NUM>, <NUM>, <NUM>, <NUM> is an electrically-conductive material, this may cause the generation of one or more eddy currents in the heating material. The flow of eddy currents in the heating material against the electrical resistance of the heating material causes the heating material to be heated by Joule heating. As mentioned above, when the heating material is made of a magnetic material, the orientation of magnetic dipoles in the heating material changes with the changing applied magnetic field, which causes heat to be generated in the heating material. In some embodiments, heat generated in the heating material of the heater <NUM> of the apparatus <NUM> could be transferred to the article <NUM>, <NUM>, <NUM>, <NUM> to heat, or further heat, the smokable material therein when the portion of the article is in the heating zone <NUM>. In other embodiments, the heater <NUM> may be omitted from the apparatus <NUM>.

In each of the above described embodiments, the apparatus <NUM> is configured to cause heating of heating material, and thus the smokable material, using induction heating. However, in other embodiments, the apparatus may be configured to use a different form of heating, such as resistive heating. In some such embodiments, the magnetic field generator <NUM> may be omitted from the apparatus <NUM>.

In each of the above described embodiments, the smokable material comprises tobacco. However, in respective variations to each of these embodiments, the smokable material may consist of tobacco, may consist substantially entirely of tobacco, may comprise tobacco and smokable material other than tobacco, may comprise smokable material other than tobacco, or may be free from tobacco. In some embodiments, the smokable material may comprise a vapour or aerosol forming agent or a humectant, such as glycerol, propylene glycol, triacetin, or diethylene glycol.

An article embodying the present invention may be a cartridge, for example.

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

In some embodiments, the apparatus discussed above is sold, supplied or otherwise provided separately from the articles <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> with which the apparatus is usable. However, in some embodiments, the apparatus and one or more of the articles <NUM>, <NUM>, <NUM>, <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:
An article (<NUM>, <NUM>, <NUM>, <NUM>) for use with an apparatus (<NUM>) for heating smokable material to volatilise at least one component of the smokable material, the article including:
a foam (<NUM>) comprising gas dispersed in a solid medium, wherein the solid medium comprises the smokable material; and
a body of heating material (<NUM>) that is heatable by penetration with a varying magnetic field, wherein the heating material is within the foam and in thermal contact with the smokable material.