REINFORCED HEAT SOURCE

Abstract

A reinforced heat source (4) for an aerosol-generating article (2), the reinforced heat source comprising: a blind combustible heat source (38) having a length L; and a non-combustible support (40) embedded in the combustible heat source, wherein the non-combustible support does not protrude outwardly from the combustible heat source.

Claims

1. A reinforced heat source for an aerosol-generating article, the reinforced heat source comprising: a blind combustible heat source having a length L; and a non-combustible support embedded in the combustible heat source, wherein the non-combustible support does not protrude outwardly from the combustible heat source.

2. A reinforced heat source according to claim 1 wherein the combustible heat source completely surrounds the non-combustible support.

3. A reinforced heat source according to claim 1 wherein the non-combustible support extends a distance of between about 0.4 L and about 0.9 L within the combustible heat source.

4. A reinforced heat source according to claim 1 wherein the non-combustible support is formed from one or more materials having a melting point of greater than or equal to about 1300° C.

5. A reinforced heat source according to claim 1 wherein the non-combustible support is formed from one or materials selected from the group consisting of chromium, iron, nickel and steel.

6. A reinforced heat source according to claim 1 wherein the non-combustible support comprises one or more non-combustible support elements.

7. A reinforced heat source according to claim 6 wherein the one or more non-combustible support elements have a length of between about 0.4 L and about 0.9 L.

8. A reinforced heat source according to claim 6 wherein the combustible heat source has a volume V and the total volume of the one or more non-combustible support elements is between about 0.00005V and about 0.05V.

9. A reinforced heat source according to claim 1 wherein the non-combustible support comprises one or more elongate rods.

10. A reinforced heat source according to claim 9 wherein the combustible heat source has a diameter D and the one or more elongate rods have a diameter of between about 0.01 D and about 0.3 D.

11. A reinforced heat source according to claim 1 wherein the non-combustible support is formed from a mesh.

12. A reinforced heat source according to claim 1 wherein the combustible heat source comprises an oxidizing agent.

13. A reinforced heat source according to claim 12 wherein the oxidizing agent is an alkaline earth metal peroxide.

14. A reinforced heat source according to claim 12 wherein the oxidizing agent is calcium peroxide.

15. An aerosol-generating article comprising: a reinforced heat source according to claim 1; and an aerosol-generating substrate.

Description

[0340] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

[0341] FIG. 1 shows a schematic longitudinal cross-section of an aerosol-generating article according to the invention;

[0342] FIG. 2 shows a schematic transverse cross-section along the line A-A of the reinforced heat source of the aerosol-generating article shown in FIG. 1;

[0343] FIGS. 3 (a), (b) and (c) show schematic transverse cross-sections of other reinforced heat sources according to the invention;

[0344] FIG. 4 (a) shows a schematic longitudinal cross-section of a further reinforced heat source according to the invention; and

[0345] FIG. 4 (b) shows a schematic transverse cross-section along the line A-A of the reinforced heat source shown in FIG. 4 (a).

[0346] The aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1 comprises a reinforced heat source 4 according to the invention and an aerosol-forming substrate 10 downstream of the reinforced heat source 4. The reinforced heat source 4 has a front end face 6 and an opposed rear end face 8 and is located at the distal end of the aerosol-generating article 2. The aerosol-generating article 2 further comprises a transfer element 12, an aerosol-cooling element 14, a spacer element 16 and a mouthpiece 18. The reinforced heat source 4, aerosol-forming substrate 10, transfer element 12, aerosol-cooling element 14, spacer element 16 and mouthpiece 18 are arranged in abutting coaxial alignment. As shown in FIG. 1, the aerosol-forming substrate 10, transfer element 12, aerosol-cooling element 14, spacer element 16 and mouthpiece 18 and a rear portion of the reinforced heat source 4 are wrapped in an outer wrapper 20 of sheet material such as, for example, cigarette paper, metallised paper, or a metal foil-paper laminate.

[0347] As shown in FIG. 1, a non-combustible substantially air impermeable barrier 22 in the form of a disc of aluminium foil is provided between the rear end face 8 of the reinforced heat source 4 and the aerosol-forming substrate 10. The barrier 22 is applied to the rear end face 8 of the reinforced heat source 4 by pressing the disc of aluminium foil onto the rear end face 8 of the reinforced heat source 4 and abuts the rear end face 8 of the reinforced heat source 4 and the aerosol-forming substrate 10.

[0348] The aerosol-forming substrate 10 is located immediately downstream of the barrier 22 applied to the rear end face 8 of the reinforced heat source 4. The aerosol-forming substrate 10 comprises a gathered crimped sheet of homogenised tobacco material 24 and a wrapper 26 around and in direct contact with the gathered crimped sheet of homogenised tobacco material 24. The gathered crimped sheet of homogenised tobacco material 24 comprises an aerosol former such as, for example, glycerine.

[0349] The transfer element 12 is located immediately downstream of the aerosol-forming substrate 10 and comprises a cylindrical open-ended hollow cellulose acetate or cardboard tube 28.

[0350] The aerosol-cooling element 14 is located immediately downstream of the transfer element 12 and comprises a gathered sheet of biodegradable polymeric material such as, for example, polylactic acid.

[0351] The spacer element 16 is located immediately downstream of the aerosol-cooling element 14 and comprises a cylindrical open-ended hollow paper or cardboard tube.

[0352] In other embodiments of the invention (not shown), the aerosol-cooling element 14 and the spacer element 16 may be replaced by an additional transfer element comprising a cylindrical open-ended hollow cellulose acetate or cardboard tube.

[0353] The mouthpiece 18 is located immediately downstream of the spacer element 16. As shown in FIG. 1, the mouthpiece 18 is located at the proximal end of the aerosol-generating article 2 and comprises a cylindrical plug of filtration material 30 such as, for example, cellulose acetate tow of very low filtration efficiency, wrapped in filter plug wrap 32.

[0354] The aerosol-generating article may further comprise a band of tipping paper (not shown) circumscribing a downstream end portion of the outer wrapper 20.

[0355] As shown in FIG. 1, the aerosol-generating article 2 further comprises a heat-conducting element 34 formed from a thermally conductive material such as, for example, aluminium foil around and in contact with a rear portion 4b of the reinforced heat source 4 and a front portion 10a of the aerosol-forming substrate 10.

[0356] In the aerosol-generating article 2 shown in FIG. 1, the aerosol-forming substrate 10 extends downstream beyond the heat-conducting element 34. That is, the heat-conducting element 34 is not around and in contact with a rear portion of the aerosol-forming substrate 10. However, it will be appreciated that in other embodiments of the invention (not shown), the heat-conducting element 34 may be around and in contact with the entire length of the aerosol-forming substrate 10. It will also be appreciated that in other embodiments of the invention (not shown), one or more additional heat-conducting elements may be provided that overlie the heat-conducting element 34.

[0357] The aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1 comprises one or more air inlets 36 around the periphery of the aerosol-forming substrate 10. As shown in FIG. 1, a circumferential arrangement of air inlets 36 is provided in the wrapper 26 of the aerosol-forming substrate 10 and the overlying outer wrapper 20 to admit cool air (shown by dotted arrows in FIG. 1) into the aerosol-forming substrate 10.

[0358] As shown in FIGS. 1 and 2, the reinforced heat source 4 comprises a blind combustible heat source 38 and a non-combustible support 40 embedded in the combustible heat source 38.

[0359] The combustible heat source 38 is a cylindrical carbonaceous heat source comprising carbon, an oxidizing agent such as, for example, an alkaline earth metal peroxide, and a binding agent. As shown in FIG. 1, the combustible heat source 38 completely surrounds the non-combustible support 40.

[0360] The non-combustible support 40 comprises a single elongate rod 42 formed from a metal or alloy such as, for example, chromium, iron, nickel, steel, or stainless steel. As shown in FIGS. 1 and 2, the single elongate rod 42 extends along the central longitudinal axis of the combustible heat source 38.

[0361] In use, a user ignites the combustible heat source 38. The oxidizing agent in the combustible heat source 38 promotes ignition and sustained combustion of the combustible heat source 38 through the release of oxygen. Once the combustible heat source 38 is ignited the user draws on the mouthpiece 18 of the aerosol-generating article 2. When a user draws on the mouthpiece 18, cool air (shown by dotted arrows in FIG. 1) is drawn into the aerosol-forming substrate 10 of the aerosol-generating article 2 through the air inlets 36.

[0362] The periphery of the front portion 10a of the aerosol-forming substrate 10 is heated by conduction through the rear end face 8 of the reinforced heat source 4 and the barrier 22 and through the heat-conducting element 34.

[0363] The heating of the aerosol-forming substrate 10 by conduction releases aerosol former and other volatile and semi-volatile compounds from the gathered crimped sheet of homogenised tobacco material 24. The compounds released from the aerosol-forming substrate 10 form an aerosol that is entrained in the air drawn into the aerosol-forming substrate 10 of the aerosol-generating article 2 through the air inlets 36 as it flows through the aerosol-forming substrate 10. The drawn air and entrained aerosol (shown by dashed arrows in FIG. 1) pass downstream through the interior of the cylindrical open-ended hollow cellulose acetate tube 28 of the transfer element 12, the aerosol-cooling element 14 and the spacer element 16, where they cool and condense. The cooled drawn air and entrained aerosol pass downstream through the mouthpiece 18 and are delivered to the user through the proximal end of the aerosol-generating article 2. The non-combustible substantially air impermeable barrier 22 on the rear end face 8 of the combustible carbonaceous heat source 4 isolates the combustible heat source 4 from air drawn through the aerosol-generating article 2 such that, in use, air drawn through the aerosol-generating article 2 does not come into direct contact with the combustible heat source 4.

[0364] The non-combustible support 40 embedded in the combustible heat source 38 reinforces the combustible heat source 38 and advantageously prevents or reduces breakage of the combustible heat source 38 during use.

[0365] FIGS. 3 (a), (b) and (c) show schematic transverse cross-sections of other reinforced heat sources 4 according to the invention. The reinforced heat sources 4 shown in FIGS. 3 (a), (b) and (c) each comprising a combustible heat source 38 and a non-combustible support 40 embedded in the combustible heat source 38.

[0366] In each of the embodiments shown in FIGS. 3 (a), (b) and (c), the non-combustible support 40 comprises a plurality of spaced-apart elongate rods 42 formed from a metal or alloy such as, for example, chromium, iron, nickel, steel, or stainless steel. The plurality of spaced-apart elongate rods 42 extend along the longitudinal axis of the combustible heat source 38.

[0367] FIGS. 4 (a) and (b) show schematic longitudinal and transverse cross-sections of a further reinforced heat source according to the invention. The reinforced heat source 4 shown in FIGS. 4 (a) and (b) comprises a combustible heat source 38 and a non-combustible support 40 embedded in the combustible heat source 38.

[0368] The non-combustible support 40 comprises a cylindrical open-ended hollow tube 44 formed from a mesh. The mesh may be formed from a metal or alloy such as, for example, chromium, iron, nickel, steel, or stainless steel. The cylindrical open-ended hollow tube 44 extends along the longitudinal axis of the combustible heat source 38.

[0369] In the reinforced heat sources 4 shown in FIGS. 1, 2, 3 (a), (b) and (c) and 4 (a) and (b) the non-combustible support 40 does not protrude outwardly from the combustible heat source 38 and the combustible heat source 38 completely surrounds the non-combustible support 40. However, it will be appreciated that in other embodiments of the invention (not shown), the non-combustible support may protrude outwardly from the combustible heat source by a distance of up to 0.1 L, where L is the length of the combustible heat source.

[0370] Reinforced heat sources according to the invention comprising a combustible heat source comprising carbon, calcium peroxide and a binding agent and a non-combustible support comprising a single elongate rod formed from stainless steel are produced having the construction shown in FIGS. 1 and 2. Four aerosol-generating articles according to the invention comprising the reinforced heat sources are produced having the construction shown in FIG. 1.

[0371] Comparative heat sources not according to the invention are produced comprising a combustible heat source having the same composition and dimensions as the combustible heat source of the reinforced heat sources according to the invention. The comparative heat sources do not comprise a non-combustible support. Four comparative aerosol-generating articles not according to the invention comprising the comparative heat sources are produced having the same construction as the aerosol-generating articles according to the invention.

[0372] The reinforced heat sources of the four aerosol-generating articles according to the invention and the comparative heat sources of the four comparative aerosol-generating articles not according to the invention are ignited using a conventional yellow flame lighter.

[0373] No ‘fall-off’ or ‘drop-off’ of the reinforced heat sources of the four aerosol-generating articles according to the invention occurs during ignition or combustion of the reinforced heat sources.

[0374] By contrast, ‘fall-off’ or ‘drop-off’ of at least a portion of all of the comparative heat sources of the four aerosol-generating articles not according to the invention occurs during or shortly after ignition of the comparative heat sources.

[0375] The results demonstrate that inclusion of a non-combustible support embedded in the combustible heat source of reinforced heat sources according to the invention advantageously improves the mechanical integrity of reinforced heat sources according to the invention.

[0376] The specific embodiments and examples described above illustrate but do not limit the invention. It is to be understood that other embodiments of the invention may be made and the specific embodiments and examples described herein are not exhaustive.