Heated aerosol-generating article with liquid aerosol-forming substrate and combustible heat generating element

Abstract

A heated aerosol-generating article is provided, including a plurality of components assembled in the form of a rod, the article having a mouth end and a distal end upstream from the mouth end, and the article further including a combustible heat-generating element disposed at the distal end of the article and configured to heat air drawn into the article, and a liquid aerosol-forming substrate disposed downstream of the combustible heat-generating element.

Claims

1. A heatable aerosol-generating article, comprising: a plurality of components assembled in the form of a rod, the article having a mouth end and a distal end upstream from the mouth end; a combustible heat-generating element disposed at the distal end of the article and being configured to heat air drawn into the article; a liquid aerosol-forming substrate disposed downstream of the combustible heat-generating element, the liquid aerosol-forming substrate being releasably contained within a frangible capsule, and the liquid aerosol-forming substrate comprising a nicotine solution and at least one aerosol-former; a liquid retention medium configured to retain the liquid aerosol-forming substrate within the article, wherein the frangible capsule is disposed within the liquid retention medium; and a heat diffuser being in thermal contact with the combustible heat-generating element and disposed between the combustible heat-generating element and the liquid aerosol-forming substrate, air entering the article through an inlet flowing through the heat diffuser to be heated before flowing over the liquid aerosol-generating substrate to form an aerosol.

2. The heatable aerosol-generating article according to claim 1, wherein the liquid retention medium is in the form of a tube having a lumen and the frangible capsule is disposed within the lumen of the tube.

3. The heatable aerosol-generating article according to claim 1, wherein the liquid retention medium comprises an absorbent polymeric material.

4. The heatable aerosol-generating article according to claim 1, further comprising a cooling section disposed downstream from the liquid aerosol-forming substrate.

5. The heatable aerosol-generating article according to claim 1, wherein the at least one aerosol-former comprises at least one polyhydric alcohol.

6. The heatable aerosol-generating article according to claim 1, wherein the liquid aerosol-forming substrate comprises between 10 weight percent and 25 weight percent water, an aerosol former, and at least one flavourant.

7. The heatable aerosol-generating article according to claim 1, further comprising a mouthpiece filter disposed at the mouth end of the article.

8. The heatable aerosol-generating article according to claim 1, wherein the plurality of components are assembled within a wrapper, the wrapper being formed from a sheet of liquid-impervious material.

9. The heatable aerosol-generating article according to claim 8, wherein the wrapper is a sheet of polymeric material, a sheet of treated paper, or a sheet of metallic foil.

10. The heatable aerosol-generating article according to claim 1, wherein the heat diffuser comprises a solid aerosol-forming substrate, the article thereby being configured to generate the aerosol from both the solid aerosol-forming substrate and the liquid aerosol-forming substrate.

11. The heatable aerosol-generating article according to claim 10, wherein the solid aerosol-forming substrate is homogenised tobacco material.

Description

(1) The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

(2) FIG. 1 shows a schematic representation of a first embodiment of a heated aerosol-generating article according to the present invention comprising a blind combustible heat-generating element;

(3) FIG. 2 shows the heated aerosol-generating article of FIG. 1 wherein the frangible capsule has been ruptured; and

(4) FIG. 3 shows a schematic representation of a second embodiment of a heated aerosol-generating article according to the present invention comprising a heat diffuser in the form of a solid aerosol-forming substrate.

(5) FIG. 1 shows a schematic representation of a heated aerosol-generating article 2 in accordance with a first embodiment the present invention.

(6) The heated aerosol-generating article 1 comprises a combustible heat-generating element 3, a heat diffuser 4, a tubular liquid retention medium 8, a cylindrical aerosol-generation section having an aerosol-cooling element 13 and a transfer element 14, and a mouthpiece filter 15. These components are arranged co-axially and circumscribed by a wrapper 16. The heated aerosol-generating article is in the form of a substantially cylindrical rod and has a mouth end at the mouthpiece filter 15 and a distal end, opposite to the mouth end, at the combustible heat-generating element 3. The total length of the article 10 is 73 mm and it has an outer diameter of 7.2 mm.

(7) The tubular liquid retention medium 8 comprises a lumen 9 and a frangible capsule 10 is located within a lumen 9 of the tubular liquid retention medium 8. The frangible capsule 10 comprises an outer shell 11 containing a liquid aerosol-forming substrate 12.

(8) The combustible heat-generating element 3 comprises a substantially circularly cylindrical body of carbonaceous material, having a length of about 10 millimetres. The combustible heat-generating element 3 is a blind combustible heat-generating element. In other words, the combustible heat-generating element 3 does not comprise any air channels extending therethrough.

(9) The heated aerosol-generating article 2 further comprises a heat diffuser 4. The heat diffuser 4 is a substantially cylindrical element formed from glass fibre. The heat diffuser may be made from other porous materials such as ceramic fibres, ceramic foams, or sintered metals. The heat diffuser 4 is arranged between the combustible heat-generating element 3 and the liquid retention medium 8. The heat diffuser 4 is in thermal contact with the combustible heat-generating element 3.

(10) A non-combustible, substantially air impermeable first barrier 6 is arranged between the proximal end of the combustible heat-generating element 3 and a distal end of the heat diffuser 4. The first barrier 6 comprises a disc of aluminium foil. The first barrier 6 also forms a heat-conducting member between the combustible heat-generating element 3 and the heat diffuser 4, for conducting heat from the proximal face of the combustible heat-generating element 3 to the distal face of the heat diffuser 4.

(11) A heat-conducting element 7 circumscribes a proximal portion of the combustible heat-generating element 3 and a distal portion of the heat diffuser 4. The heat-conducting element 7 comprises a tube of aluminium foil. The heat-conducting element 7 is in direct contact with the proximal portion of the combustible heat-generating element 3 and the heat diffuser 4.

(12) The heated aerosol-generating article 2 further comprises a liquid retention medium 8 arranged at the proximal end of the heat diffuser 4. The liquid retention medium 8 comprises a cylindrical open-ended hollow tube of high retention material, such as PET fibres. The liquid retention medium 8 has a central lumen 9 extending centrally through the liquid retention medium 8 and aligned with the longitudinal axis of the heated aerosol-generating article.

(13) The tubular liquid retention medium 8 has a length of 8 mm and is formed from fibrous cellulose acetate material. The liquid retention medium 8 has a capacity to absorb 35 microlitres of liquid. The lumen 9 of the tubular liquid retention medium 8 provides an air flow path through the liquid retention medium and also acts to locate the frangible capsule 10. The material of the liquid retention medium may be any other suitable fibrous or porous material.

(14) The frangible capsule 10 is shaped as an oval spheroid and has the long dimension of the oval aligned with the axis of the lumen. The oval spheroid shape of the capsule 10 may mean that it is easier to break than if it was circular spherical in shape, but other shapes of capsule may be used. The capsule has an outer shell 11 comprising a gelatin based polymeric material surrounding a liquid aerosol-forming substrate.

(15) The liquid aerosol-forming substrate 12 comprises propylene glycol, nicotine extract, and 20 weight percent water. A wide range of flavourants may be optionally added. A wide range of aerosol-formers may be used as alternative, or in addition to, propylene glycol. The capsule 10 has a long axis that is about 4 mm in length and contains a volume of about 33 microlitres of liquid aerosol-forming substrate.

(16) The aerosol-cooling element 13 comprises a crimped and gathered sheet of polymeric material. The sheet of polymeric material is not densely packed and the aerosol-cooling element does not cause significant pressure drop in air passing through the section. The aerosol-cooling element has a length of about 18 mm, an outer diameter of about 7.12 mm, and an inner diameter of about 6.9 mm. In one embodiment, the aerosol-cooling element is formed from a sheet of polylactic acid having a thickness of 50 mm±2 mm. The sheet of polylactic acid has been crimped and gathered to define a plurality of channels that extend along the length of the aerosol-cooling element. The total surface area of the aerosol-cooling element is between 8000 mm.sup.2 and 9000 mm.sup.2, which is equivalent to approximately 500 mm.sup.2 per mm length of the aerosol-cooling element. The specific surface area of the aerosol-cooling element is approximately 2.5 mm.sup.2/mg and it has a porosity of between 60% and 90% in the longitudinal direction. The polylactic acid is kept at a temperature of 160 degrees Celsius or less during use.

(17) Porosity is defined herein as a measure of unfilled space in a rod including material such as an aerosol-cooling element. For example, if a diameter of the rod was 50% unfilled by the aerosol-cooling element, the porosity would be 50%. Likewise, a rod would have a porosity of 100% if the inner diameter was completely unfilled and a porosity of 0% if completely filled. The porosity may be calculated using known methods.

(18) The transfer element 14 comprises a hollow tube of polymeric material having a length of about 18 mm, an outer diameter of about 7.12 mm, and an inner diameter of about 6.9 mm.

(19) The aerosol-generating section may not comprise both the aerosol-cooling element and the transfer element. The aerosol-generating section may comprise one of the aerosol-cooling element and the transfer element.

(20) The mouthpiece filter 15 has a length of 7 mm and is formed from cellulose acetate tow. Other suitable mouthpiece filters are known in the art.

(21) The wrapper 16 is a non-porous wrapper. Suitable non-porous materials are known, for example polymeric films or hydrophobic papers. In some embodiments, a traditional cigarette paper may be used.

(22) A plurality of air inlets 17 are arranged over the heat diffuser 4, proximal to the heat-conducting element 7, to enable ambient air to be drawn into the heated aerosol-generating article 2. The air inlets 17 comprise a plurality of perforations through the liquid impervious layer 16.

(23) The heated aerosol-generating article 2 comprises an airflow path extending between the plurality of air inlets 17 and the mouthpiece filter 15. The heat diffuser 4 is arranged within the air flow path of the heated aerosol-generating article.

(24) When a user draws on the mouthpiece 15 of the heated aerosol-generating article 2, ambient air is drawn into the heated aerosol-generating article 2 through the plurality of air inlets 17. The air drawn into the heated aerosol-generating article 2 flows through the heat diffuser 4 to the liquid retention medium 8, and from the liquid retention medium 8 to the cooling element 13, the spacer element 14 and the mouthpiece 15, where the air is delivered to the user for inhalation.

(25) A method of using the heated aerosol-generating article 2 will be described with relation to the embodiment of FIG. 1.

(26) The first step is to release the liquid aerosol-forming substrate from its frangible capsule. This is achieved by squeezing the article in the region of the capsule between forefinger and thumb to apply an external force to rupture the frangible capsule. Once ruptured, the liquid aerosol-forming substrate is released onto and rapidly absorbed by the liquid retention medium. The article is thus primed and ready for ignition of the combustible heat-generating element, as shown in FIG. 2.

(27) A user ignites the combustible heat-generating element 3 by exposing the combustible heat-generating element 3 to an external heat source, such as a lighter. The combustible heat-generating element 3 begins to combust and generate heat. Heat is transferred from the combustible heat-generating element 3 to the heat diffuser 4, via conduction through the heat-conducting member 6 and the heat-conducting element 7. When the user draws on the mouthpiece 15, ambient air is drawn into the aerosol-generating article 2, through air inlets 17. The air drawn into the aerosol-generating article 2 is drawn directly into the heat diffuser 4. The air is heated as it is drawn proximally through the heat diffuser 4 and into the liquid retention medium 8. The heated air heats the liquid retention medium 8, heating the liquid aerosol-forming substrate 12, and volatile components of the heated aerosol-forming substrate 12 are vapourised and entrained in the heated air. The entrained vapour is drawn out of the liquid retention medium 8 towards the mouthpiece 15. As the vapour is drawn towards the mouthpiece 15, through the aerosol-cooling element 13 and spacer element 14, the vapour cools to form an aerosol. The aerosol is draw into the mouthpiece 15 and out of the proximal end of the article 2 to be delivered to the user for inhalation.

(28) It will be appreciated that the substantially air-impermeable first barrier 6 inhibits air being drawn through the combustible heat-generating element 3 and into the heat diffuser 4. As such, the first barrier 6 substantially isolates the airflow pathway of the heated aerosol-generating article 2 from the combustible heat-generating element 3.

(29) FIG. 3 illustrates a heated aerosol-generating article 102 according to a second embodiment of the present invention. The heated aerosol-generating article 102 is identical to the article 2 described in relation to FIG. 1, with the difference that the glass fibre heat diffuser 4 has been replaced by a cylindrical body of solid aerosol-forming substrate 104 wrapped in a filter plug wrap 105. Airflow through the article 102 is also identical to the airflow through the article 2 described in relation to FIG. 1, with the difference being that as the air is heated as it is being drawn proximally through the heat diffuser 4 and into the liquid retention medium 8, volatile components of the heated solid aerosol-forming substrate 104 are vapourised and entrained in the heated air.

(30) The specific embodiments described above are intended to illustrate the invention. However, other embodiments may be made without departing from the scope of the invention as defined in the claims, and it is understood that the specific embodiments described above are not intended to be limiting.