Smoking article with front-plug and aerosol-forming substrate and method

Abstract

A smoking article is provided, including a plurality of elements including a front-plug and an aerosol-forming substrate. A hole or slit is defined through the front-plug, through which a heating element may be inserted. In use, a heating element is inserted into the smoking article through the hole or slit and the aerosol-forming substrate is heated to generate an aerosol. When the heating element is subsequently withdrawn from the smoking article, the front-plug acts to retain the aerosol-forming substrate within the smoking article.

Claims

1. A smoking article, comprising: a plurality of elements, including a front-plug and an aerosol-forming substrate assembled within a cigarette wrapper and forming a rod having a mouth end and a distal end upstream from the mouth end, the front-plug being disposed upstream of the aerosol-forming substrate within the rod, wherein the front-plug is formed of a resilient material and defines a slit configured for insertion of a heating element therethrough, the front-plug and the aerosol-forming substrate being disposed within the rod such that the heating element, when inserted into the smoking article through the slit, contacts the aerosol-forming substrate, wherein the front-plug is substantially cylindrical and has a diameter of 5 mm or greater and a length of at least 4 mm, wherein the slit is dimensioned so as to wipe a surface of the heating element when the heating element is withdrawn from the front-plug, and so as to clean the surface due to an interference between the surface and the front-plug; and a filter disposed at the mouth end of the rod, wherein the front-plug incorporates the aerosol-forming substrate, and wherein a density of the aerosol-forming substrate incorporated in the front-plug is increased at the distal end of the rod.

2. The smoking article according to claim 1, in which the front-plug comprises a filter material such that air can be drawn through the front-plug.

3. The smoking article according to claim 1, in which the aerosol-forming substrate comprises processed tobacco.

4. The smoking article according to claim 1, in which the front-plug is configured to prevent egress of the aerosol-forming substrate as the heating element is withdrawn from the smoking article.

5. The smoking article according to claim 1, in which the aerosol-forming substrate is a crimped tobacco.

Description

(1) Specific embodiments will now be described with reference to the figures, in which;

(2) FIG. 1 is a schematic cross-sectional diagram of a smoking article according to a first embodiment engaged with an aerosol-generating device;

(3) FIG. 2 is a schematic diagram illustrating a front-end projection of the smoking article according to the first embodiment, showing penetration of the smoking article, through a slit defined in a front-plug, by a heating element;

(4) FIG. 3A is a schematic diagram illustrating a front-end projection of a smoking article according to a second embodiment, showing penetration of the front-plug of the smoking article by a heating element; and

(5) FIG. 3B is a schematic diagram illustrating a front-end projection of a smoking article according to a third embodiment, showing penetration of the front-plug of the smoking article by a heating element.

(6) FIG. 1 illustrates a smoking article 1 according to a first embodiment. The smoking article 1 comprises five elements, a front-plug 2, an aerosol-forming substrate 7, a hollow cellulose acetate tube 6, a transfer section 4, and a mouthpiece filter 3. These five elements are arranged sequentially and in coaxial alignment and are assembled by a cigarette paper 5 to form a rod 15. The rod has a mouth-end 20, which a user inserts into his or her mouth during use, and a distal end 30 located at the opposite end of the rod 15 to the mouth end 20. Elements located between the mouth-end 20 and the distal end 30 can be described as being upstream of the mouth-end 20 or, alternatively, downstream of the distal end 30.

(7) When assembled, the rod 15 is 52 millimetres long and has a diameter of 7.2 millimetres.

(8) The front-plug 2 is a cylindrical portion of cellulose acetate tow having a length of 7 millimetres. The fibres of the cellulose acetate tow are aligned with the longitudinal direction of the rod 15. The front-plug 2 defines eight slits 23 that extend radially from a common point located centrally on an end face of the front-plug 2. The eight slits 23 are angularly separated from each other by 45 degrees and extend through the front-plug 2. As opposing slits are angularly separated by 180 degrees and effectively form a single slit, an alternative way to describe the same arrangement of slits would be four slits that are angularly spaced that intersect at a common point centrally on an end face of the front-plug 2.

(9) The aerosol-forming substrate 7 is located downstream of the front-plug 2 and comprises a bundle of crimped cast-leaf tobacco wrapped in a filter paper. The cast-leaf tobacco includes additives, including glycerine as an aerosol-forming additive.

(10) The tube 6 is located immediately downstream of the aerosol-forming substrate 7 and is formed from cellulose acetate. The tube 6 defines an aperture having a diameter of 3.3 millimetres. One function of the tube 6 is to locate the aerosol-forming substrate 7 towards the distal end 30 of the rod 15 so that it can be contacted with a heating element. The tube 6 acts to prevent the aerosol-forming substrate 7 from being forced along the rod 15 towards the mouth-end 20 when a heating element is inserted.

(11) The transfer section 4 comprises a thin-walled tube of 18 millimetres in length. The transfer section 4 allows volatile substances released from the aerosol-forming substrate 7 to pass along the rod 15 towards the mouth end 20. The volatile substances may cool within the transfer section 4 to form an aerosol.

(12) The mouthpiece filter 3 is a conventional mouthpiece filter formed from cellulose acetate tow, and having a length of 7 millimetres.

(13) The five elements identified above are assembled by being tightly wrapped within a cigarette paper 5. The cigarette paper 5 in this specific embodiment is a conventional cigarette paper. For example, the cigarette paper may be a porous material with a non-isotropic structure comprising cellulose fibres (crisscross of fibres interlinked by hydrogen bonds), one or more fillers and one or more combustion agents. The one or more fillers may be, for example, calcium carbonate (CaCO.sub.3) and the one or more combustion agents may be, for example, one or more of the following: potassium/sodium citrate; sodium acetate; mono-ammonium phosphate (MAP); and di-sodium phosphate (DSP). The final composition of the cigarette paper per square metre may be approximately 25 g cellulose fibres, 10 g calcium carbonate, and 0.2 g combustion agent. The porosity of the cigarette paper may be between approximately 0 Coresta and approximately 120 Coresta. The interface between the cigarette paper 5 and each of the elements locates the elements and defines the rod 15 of the smoking article 1.

(14) Although the specific embodiment described above and illustrated in FIG. 1 has five elements assembled in a cigarette paper, it will now be clear to one of ordinary skill in the art that a smoking article according to the embodiments discussed here may have additional elements and these elements may be assembled in an alternative cigarette wrapper or equivalent. Likewise, a smoking article according to the embodiments discussed here may have fewer elements. Moreover, it will now be apparent to one of ordinary skill in the art that various dimensions for the elements discussed in relation to the various embodiments discussed here are merely exemplary, and that suitable alternative dimensions for the various elements may be chosen without deviating from the spirit of the embodiments discussed herein.

(15) The smoking article of the first embodiment is consumed or smoked in conjunction with a suitable aerosol-generating device. FIG. 1 illustrates the smoking article when engaged with such a device 11 for consumption.

(16) The aerosol-generating device 11 comprises a sheath 12 for receiving the smoking article 1 for consumption. A heating element 8 is located within the sheath 12 and positioned to engage with the distal end 30 of the smoking article 1. The heating element 8 is shaped in the form of a blade terminating in a point 40.

(17) As the smoking article 1 is pushed into the sheath 12 the point 40 of the heating element 8 engages with one or more of the slits 23 defined through the front-plug 2. The heating element 8 is blade-shaped, its width being greater than its thickness. The smoking article 1 may need to be rotated by an angle of up to 22.5 degrees to correctly align with a slit or pair of slits 23, as these are angularly separated by 45 degrees. By applying a force to the smoking article 1 once the blade is engaged with a slit 23, the heating element 8 is inserted through the slit 23 and penetrates the front-plug 2. Material forming the front-plug 2 deforms to allow the heating element 8 to be inserted, and contact is maintained between the front-plug 2 and a surface of the heating element 8.

(18) As the heating element 8 is inserted further into the smoking article 1, the point 40 of the heating element 8 contacts the plug of aerosol-forming substrate 7. The application of further pressure causes the heating element 8 to penetrate into the aerosol-forming substrate 7. Once the optimum engagement position has been reached, further penetration is prevented as the distal end 30 of the smoking article 1 abuts an end wall of the sheath 12, which acts as a stop.

(19) When the smoking article 1 is properly engaged with the aerosol-generating device 11, the heating element 8 has been inserted through the front-plug 2 and is located within the aerosol-forming substrate 7 in contact with aerosol-forming material. An insulating collar 9 may surround a portion of the heating element 8 that is in contact with the front-plug 2. The collar 9 may alternatively be a cool zone provided on the length of the heating element 8. Such a collar may prevent the heating element 8 from burning or melting the front-plug 2.

(20) FIG. 2 is a front-end view of the smoking article 1 when engaged with the heating element 8. This view shows the cigarette paper 5 in contact with the front-plug 2. The heating element 8, which can be seen to have a blade shaped cross-section, has been inserted through slits 23 extending through the front-plug 2. The heating element 8 has deformed the cellulose acetate material forming the front-plug 2 slightly on passing through the slits 23, and the resilience of this cellulose acetate material results in contact between the front-plug 2 and outer surfaces of the heating element 8.

(21) The aerosol-generating device 11 comprises a power supply and electronics (not shown) that allow the heating element 8 to be actuated. Such actuation may be manually operated or may occur automatically in response to a user drawing on the smoking article 1. When the heating element 8 is actuated, the aerosol-forming substrate 7 is heated and volatile substances are generated or evolved. As a user draws on the mouth end 20 of the smoking article 1, air is drawn into the smoking article 1 and the volatile substances condense to form an inhalable aerosol. This aerosol passes through the mouth-end 20 of the smoking article 1 and into the user's mouth.

(22) The heating element 8 is heated to a temperature of about 375 degrees Celsius in order to generate an aerosol from the aerosol-forming substrate 7. As volatile substances are driven off the aerosol-forming substrate 7 by heat, the aerosol-forming substrate 7 dries out and shrinks. This can result in the aerosol-forming substrate 7 gripping the heating element 8. Simultaneously, the shrinkage of the aerosol-forming substrate 7 may cause a loss in contact with the cigarette paper 5. In the first embodiment the aerosol-forming substrate 7 is in the form of a plug, and the shrinkage causes this plug to become loose within the rod 15 of the smoking article 1.

(23) After use, the user withdraws the smoking article 1 from the aerosol-generating device 11. The smoking article 1 is withdrawn from the sheath 12 and the heating element 8 slides out of the front-plug 2. Because the adherence between the heating element 8 and the aerosol-forming substrate 7 is greater than the adherence between the aerosol-forming substrate 7 and the cigarette paper 5, the aerosol-forming substrate 7 moves towards the distal end 30 with the heating element 8. However, the front-plug 2 blocks the path of the aerosol-forming substrate 7. This allows the heating element 8 to be withdrawn from the aerosol-forming substrate 7 without removing the aerosol-forming substrate 7 from the smoking article 1.

(24) Particles of the aerosol-forming substrate 7 or residues derived from the aerosol-forming substrate 7 may become stuck to the heating element 8 during operation. As the heating element 8 is withdrawn from the smoking article 1, the outer surface of the heating element 8 is wiped by the front-plug 2. Thus, the heating element 8 is automatically cleaned by wiping every time a smoking article 1 is removed from the aerosol-generating device 11.

(25) The first embodiment described above with reference to FIGS. 1 and 2 describes a smoking article 1 having its distal end closed by a front-plug 2 that has a plurality of through slits 23. Such a front-plug 2 requires a heating element 8 to be forced through the slits 23 defined through the front-plug 2 to contact the aerosol-forming substrate 7.

(26) A second embodiment of a smoking article 100 is illustrated in FIG. 3A (end view only). The smoking article 100 of FIG. 3A is identical to the smoking article 1 of the first embodiment described above apart from the configuration of the front-plug 102. The front-plug 102 is formed from cellulose acetate and is assembled in contact with a cigarette paper 5, but the front-plug 102 defines a substantially circular through-hole 103 allowing through-access to a heating element of an aerosol-generating device. The heating element can pass through the front-plug 102 with minimal insertion force required. The circular shape of the hole 103 means that there is no special orientation relationship required between the smoking article 100 and the heating element in order to engage the smoking article 100 with the aerosol-generating device.

(27) In use, the front-plug 102 of the smoking article 100 acts in the same way as described above to prevent egress of an aerosol-forming substrate from the smoking article 100.

(28) A third embodiment of a smoking article 300 is illustrated in FIG. 3B (end view only). The smoking article 300 of FIG. 3B is identical to the smoking article 1 of the first embodiment described above apart from the configuration of the front-plug 302. The front-plug 302 is formed from cellulose acetate and is assembled in contact with a cigarette paper 5, but the front-plug defines a star-shaped hole 303 allowing through-access to a heating element of an aerosol-generating device. The hole 303 lowers the insertion force required to insert a heating element into the smoking article 300. The star-shape of the hole 303 allows the heating element to engage with the front-plug 302 of the smoking article 300 and prevent rotation of the smoking article 300 while it is being consumed.

(29) In use, the front-plug 302 of the smoking article 300 acts in the same way as described above to prevent egress of an aerosol-forming substrate from the article.

(30) The exemplary embodiments described above are not limiting. In view of the above discussed exemplary embodiments, other embodiments consistent with the above exemplary embodiments will now be apparent to one of ordinary skill in the art.