Abstract
An aerosol generating article including a tubular element is provided, the tubular element including: a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body, the cavity having an area as measured perpendicular to a longitudinal direction of the tubular element; and a folded end portion forming a first end wall at a first end of the tubular body, the first end wall delimiting an opening for airflow between the cavity and an exterior of the tubular element, the opening having an area, as measured perpendicular to the longitudinal direction of the tubular element, of from about 0.6 percent to about 60 percent of an area of the cavity.
Claims
1.-15. (canceled)
16. An aerosol generating article comprising a tubular element, the tubular element comprising: a tubular body defining a cavity extending from a first end of the tubular body to a second end of the tubular body, the cavity having an area as measured perpendicular to a longitudinal direction of the tubular element; and a folded end portion forming a first end wall at a first end of the tubular body, the first end wall delimiting an opening for airflow between the cavity and an exterior of the tubular element, wherein the opening has an area, as measured perpendicular to the longitudinal direction of the tubular element, of from about 0.6 percent to about 60 percent of an area of the cavity.
17. The aerosol generating article according to claim 16, wherein the opening has an area, as measured perpendicular to the longitudinal direction of the tubular element, of from about 2.5 percent to about 9.5 percent of the area of the cavity.
18. The aerosol generating article according to claim 16, wherein the opening has a diameter of from about 0.5 millimetre to about 5 millimetres.
19. The aerosol generating article according to claim 18, wherein the opening has a diameter of from about 1 millimetre to about 2 millimetres.
20. The aerosol generating article according to claim 16, wherein the tubular body has an outer diameter, and wherein the opening of the first end wall has a diameter of from about 7 percent to about 70 percent of the outer diameter of the tubular body.
21. The aerosol generating article according to claim 16, wherein the tubular element is formed from a paper material.
22. The aerosol generating article according to claim 16, wherein at least a first portion of the tubular element forming the first end wall is air impermeable.
23. The aerosol generating article according to claim 16, wherein the first end wall extends partially into the cavity of the tubular body and forms an angle of less than 90 degrees with an inner surface of the tubular body.
24. The aerosol generating article according to claim 16, further comprising a first element comprising an aerosol-generating substrate, wherein the tubular element is positioned upstream or downstream of the first element.
25. The aerosol generating article according to claim 24, wherein the tubular element is adjacent to the first element.
26. The aerosol generating article according to claim 25, wherein the first end wall of the tubular element is adjacent to the first element.
27. The aerosol generating article according to claim 26, wherein the first end wall of the tubular element is in contact with the aerosol-generating substrate.
28. The aerosol generating article according to claim 24, wherein the aerosol-generating substrate is a rod of aerosol-generating substrate, and wherein the first element further comprises a susceptor element arranged within the rod of aerosol-generating substrate.
29. The aerosol generating article according to claim 24, wherein the tubular element is a first tubular element, and is positioned downstream of the aerosol forming substrate with the first end wall of the first tubular element being adjacent to a downstream end of the aerosol-generating substrate.
30. The aerosol generating article according to claim 16, wherein there is no ventilation zone about the tubular body of the tubular element.
Description
[0307] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:
[0308] FIG. 1 shows a schematic side sectional view of an aerosol-generating article in accordance with a first embodiment of the invention;
[0309] FIG. 2 shows a schematic side sectional view of an aerosol-generating article in accordance with a second embodiment of the invention;
[0310] FIG. 2 shows a schematic side sectional view of an aerosol-generating article in accordance with a third embodiment of the invention;
[0311] FIG. 4 shows a perspective view of a tubular element of the aerosol-generating article of the first embodiment of the invention; and
[0312] FIGS. 5A to 5D show schematic side sectional views depicting the stages of formation of the tubular element of the aerosol-generating article of FIG. 1;
[0313] FIG. 6 shows a schematic side sectional view of an aerosol-generating article in accordance with a fourth embodiment of the invention;
[0314] FIG. 7 shows a schematic side sectional view of an aerosol-generating article in accordance with a fifth embodiment of the invention;
[0315] FIG. 8 shows a schematic side sectional view of an aerosol-generating article in accordance with a sixth embodiment of the invention;
[0316] FIG. 9 shows a schematic side sectional view of an aerosol-generating article not in accordance with an embodiment of the invention;
[0317] FIGS. 10A and 10B depict air flow fields comparing an aerosol-generating article in accordance with an embodiment of the invention with an aerosol-generating article not in accordance the invention;
[0318] FIGS. 11A and 11B depict air flow fields comparing an aerosol-generating article in accordance with an embodiment of the invention with an aerosol-generating article not in accordance the invention; and
[0319] FIG. 12 shows a schematic side sectional view of the tubular element of FIG. 1.
[0320] FIG. 1 shows an aerosol-generating article 1 article in accordance with a first embodiment of the invention. The aerosol-generating article 1 comprises a first element 11 comprising an aerosol-generating substrate 12 and a downstream section 14 at a location downstream of the first element 11. Further, the aerosol-generating article 1 comprises an upstream section 16 at a location upstream of the first element 11. Thus, the aerosol-generating article 1 extends from an upstream or distal end 18 to a downstream or mouth end 20.
[0321] The aerosol-generating article has an overall length of about 45 millimetres.
[0322] The downstream section 14 comprises a tubular element 100 located immediately downstream of the first element 11, the tubular element 100 being in longitudinal alignment with the first element 11. In the embodiment of FIG. 1, the upstream end of the tubular element 100 abuts the downstream end of the first element 11 and in particular the downstream end of the aerosol-generating substrate 12.
[0323] In addition, the downstream section 14 comprises a mouthpiece element 42 at a location downstream of the tubular element 100. In more detail, the mouthpiece element 42 is positioned immediately downstream of the tubular element 100. As shown in FIG. 1, an upstream end of the mouthpiece element 42 abuts the downstream end 40 of the tubular element 100.
[0324] The mouthpiece element 42 is provided in the form of a cylindrical plug of low-density cellulose acetate. The mouthpiece element 42 has a length of about 12 millimetres and an external diameter of about 7.25 millimetres. The RTD of the mouthpiece element 42 is about 12 millimetres H.sub.2O.
[0325] The aerosol-generating article 1 comprises a ventilation zone 60 provided at a location along the tubular element 100. In more detail, the ventilation zone is provided at about 4 millimetres from the downstream end of the tubular element 100. A ventilation level of the aerosol-generating article 10 is about 40 percent.
[0326] The first element 11 is in the form of a rod comprising the aerosol-generating substrate 12 of one of the types described above. The aerosol-generating substrate 12 may substantially define the structure and dimensions of the rod 11. The rod 11 may further comprise a wrapper (not shown) circumscribing the aerosol-generating substrate 12. The rod 11 comprising the aerosol-generating substrate has an external diameter of about 7.25 millimetres and a length of about 12 millimetres.
[0327] The first element 11 also comprises an elongate susceptor element 44 within the aerosol-generating substrate 12. In more detail, the susceptor element 44 is arranged substantially longitudinally within the aerosol-generating substrate 12, such as to be approximately parallel to the longitudinal direction of the rod 11. As shown in the drawing of FIG. 1, the susceptor element 44 is positioned in a radially central position within the rod and extends effectively along the longitudinal axis of the rod 11.
[0328] The susceptor element 44 extends all the way from an upstream end to a downstream end of the aerosol-generating substrate 12. In effect, the susceptor element 44 has substantially the same length as the first element 11 comprising the aerosol-generating substrate 12.
[0329] In the embodiment of FIG. 1, the susceptor element 44 is provided in the form of a strip and has a length of about 12 millimetres, a thickness of about 60 micrometres, and a width of about 4 millimetres.
[0330] The upstream section 16 comprises an upstream element 46 located immediately upstream of the first element 11, the upstream element 46 being in longitudinal alignment with the first element 11. In the embodiment of FIG. 1, the downstream end of the upstream element 46 abuts the upstream end of the first element 11 and in particular the upstream end of the aerosol-generating substrate 12. This advantageously prevents the susceptor element 44 from being dislodged. Further, this ensures that the consumer cannot accidentally contact the heated susceptor element 44 after use.
[0331] The upstream element 46 is provided in the form of a cylindrical plug of cellulose acetate circumscribed by a stiff wrapper. The upstream element 46 has a length of about 5 millimetres. The RTD of the upstream element 46 is about 30 millimetres H.sub.2O.
[0332] The aerosol-generating article 1 further includes an outer wrapper 109 circumscribing at least the tubular element. As shown in FIG. 1, the outer wrapper also circumscribes the first element 11, the mouthpiece element 42 and the upstream element 46. The outer wrapper 109 extends from an upstream or distal end 18 to a downstream or mouth end 20.
[0333] The tubular element 100 comprises a tubular body 103 defining a cavity 106 extending from a first end 101 of the tubular body 103 to a second end 102 of the tubular body 103. The tubular element 100 also comprises a folded end portion forming a first end wall 104 at the first end 101 of the tubular body 103. The first end wall 104 delimits and opening 105, which permits airflow between the cavity 106 and the exterior of the tubular element 100. In particular, the embodiment of FIG. 1 is configured so that aerosol may flow from the first element 11 through the opening 105 into the cavity 106.
[0334] The cavity 106 of the tubular body 103 is substantially empty, and so substantially unrestricted airflow is enabled along the cavity 106. Consequently, the RTD of the tubular element 100 can be localised at a specific longitudinal position of the tubular element 100namely, at the first end wall 104and can be controlled through the chosen configuration of the first end wall 104 and its corresponding opening 105. In the embodiment of FIG. 1, the RTD of the tubular element 100 (which is essentially the RTD of the first end wall 104) is substantially 10 millimetres H.sub.2O. In the embodiment of FIG. 1, the tubular element 100 has a length of about 16 millimetres, an external diameter of about 7.25 millimetres, and an internal diameter (D.sub.FTS) of about 6.5 millimetres. Thus, a thickness of a peripheral wall of the tubular body 103 is about 0.375 millimetres.
[0335] As shown in FIG. 1, and also in more detail in the perspective view of FIG. 4, the first end wall 104 extends substantially transverse to the longitudinal direction of the aerosol generating article 1 and the longitudinal direction of the tubular element 100. The opening 105 is the only opening in the first end wall 104 and the opening 105 is positioned in a generally radially central position of the tubular element 100. Consequently, the first end wall 104 is generally annular shaped.
[0336] The combination of the first end wall 104 and its corresponding opening 105 provide an effective barrier arrangement which may restrict movement of the aerosol-generating substrate, whilst also enabling one or both of air and aerosol to flow from the first element 11 and through the opening 105 into the cavity 106. The opening 105 is generally aligned with the radially central position of the susceptor element 44 of the first element 11. This may be advantageous as it helps to keep a distance between the first end wall 105 and the susceptor, and thus mitigate undesirable heating of the first end wall 105. This may also be advantageous as it can provide direct unimpeded downstream flow of aerosol produced by the portion of the aerosol-generating substrate in close proximity to the susceptor element 44.
[0337] As will be described in more detail below with respect to FIGS. 5A-5D, the first end wall 104 is formed by folding an end portion of the tubular element 100 about a fold point. The fold point generally corresponds to the first end of the tubular body 103 of the tubular element 100.
[0338] FIG. 2 shows an aerosol-generating article 2 in accordance with a second embodiment of the invention. The aerosol-generating article 2 of the second embodiment is generally the same as the aerosol-generating article 1 of the first embodiment, with the exception that the aerosol-generating article 2 of the second embodiment does not comprise an upstream element 46 is provided in the form of a cylindrical plug of cellulose acetate circumscribed by a stiff wrapper. Instead, the aerosol-generating article 2 of the second embodiment comprises a second tubular element 200 located immediately upstream of the first element 11. Consequently, in this second embodiment, the tubular element 100 located immediately downstream of the first element 11 is referred to as a first tubular element 100.
[0339] The second tubular element 200 comprises a tubular body 203 defining a cavity 206 extending from a first end of the tubular body 203 to a second end of the tubular body 203. The tubular element 200 also comprises a folded end portion forming a first end wall 204a at the first end of the tubular body 103. The first end wall 204a delimits and opening 205a, which permits airflow between the cavity 206 and the exterior of the second tubular element 200. In particular, the embodiment of FIG. 2 is configured so that air may flow from the cavity 206 through the opening 205a and into the first element 11.
[0340] The second tubular element 200 is therefore similar to the first tubular element 100 in that an end portion of the tubular element 200 is folded to form an end wall 205a, which extends substantially transverse to the longitudinal direction of the aerosol-generating article, and which is disposed adjacent to an end of the aerosol-generating substrate 12. In this case, the second tubular element 200 is disposed upstream, rather than downstream, of the first element 11 comprising the aerosol-generating substrate 12, meaning that the end wall 204a is disposed adjacent to the upstream end of the aerosol-generating substrate 12.
[0341] However, unlike the first tubular element, the second tubular element 200 also comprises a second end wall 204b at the second end of its tubular body 203. This second end wall 204b is formed by folding an end portion of the second tubular element 200 at the second end of the tubular body of the second tubular element 200. The second end wall 204b delimits and opening 205b, which also permits airflow between the cavity 206 and the exterior of the second tubular element 200. In the case of the second end wall 204b, the opening 205b is configured to so that air may flow from the exterior of the aerosol-generating article 2 through the opening 205b and into the cavity 206. The opening 205b therefore provides the conduit through which air can be drawn into the aerosol-generating article 2 and through the aerosol-generating substrate 12. In the embodiment of FIG. 2, the first end wall 204a of the second tubular element 200 may be referred to as the downstream end wall of the second tubular element 200. Similarly, the second end wall 204b of the second tubular element 200 may be referred to as the upstream end wall of the second tubular element 200.
[0342] FIG. 3 shows an aerosol-generating article 3 in accordance with a third embodiment of the invention. The aerosol-generating article 3 of the third embodiment is generally the same as the aerosol-generating article 1 of the first embodiment, with the exception that the aerosol-generating article 3 of the third embodiment does not comprise any form of upstream element 46 upstream of the first element 11. Consequently, the upstream or distal end 18 of the aerosol-generating article 3 is defined by the first element 11. Furthermore, in the third embodiment of the invention the first element 11 does not comprise a susceptor element 44 located within the aerosol-generating substrate 12. Such an aerosol-generating article 3 may therefore be one which is configured to receive a heater blade of an aerosol-generating device. The heater blade may be inserted into the aerosol-generating substrate 12 through the upstream end 18 of the aerosol-generating article 3.
[0343] The tubular element 300 of the aerosol-generating article 3 of the third embodiment is substantially the same as the tubular element 100 of the aerosol-generating article 1 of the first embodiment, with the exception that the tubular element 300 is longer than the tubular element 100.
[0344] FIGS. 5A to 5D show a tubular element for an aerosol generating article in according with the invention, through different stages of its formation. These Figures therefore illustrate a method of forming the tubular element, such as the tubular element 100 of FIG. 1.
[0345] As illustrated by FIG. 5A, the method commences by providing a tubular element 500 comprising a first end portion 504 and a tubular body 103 adjacent to and integral with the first end portion 504. To form the first end wall 104, a folding force is applied to the tubular element 500 to bend the first end portion 504 about a fold point 501 corresponding to the first end of the tubular body 103.
[0346] The folding force deflects the first end portion 504 inwards relative to the tubular body 103 (as indicated by the dashed curved arrows in FIGS. 5A, 5B and 5C) and towards the cavity 106 of the tubular body 103. The folding force continues to be applied until the first end portion 504 has been folded by an angle of greater than 90 degrees, as measured relative to the walls of the tubular body 103. Such a position is depicted in FIG. 5C. As can be seen from FIG. 5C, in such a position, at least part of the first end portion 504 of the tubular element 500 extends into the cavity 106 of the tubular body 103. Put another way, at least part of the first end portion 504 of the tubular element 500 has a longitudinal position which resides between that of the first end of the tubular body 103 and that of the second end of the tubular body 103.
[0347] Once the first end portion 504 reaches the position of FIG. 5C, the folding force ceases to be applied. At this point, the inherent resilient properties of the paper material (such as paper, paperboard or cardboard) of the tubular element 500 will cause the first end portion 504 to partially revert back along its folding path, such that the first end portion 504 reaches a positon in which it extends substantially transverse to the longitudinal direction of the tubular body 103. This position is illustrated by FIG. 5D, which depicts the fully formed tubular element 100. In particular, the folded first end portion 504 forms a first end wall 104 at the first end of the tubular body 103, the first end wall 104 delimiting an opening 105 for airflow between the cavity 106 and the exterior of the tubular element 100.
[0348] In the arrangement of FIGS. 5A to 5D the second end of the tubular element 500 is not folded; however, it will be appreciated that similar method steps may be applied to this second end of the tubular element 500 in order to arrive at a tubular element having two folded end portions, each forming respective first and second end walls for the tubular element.
[0349] FIG. 6 shows an aerosol-generating article 6 in accordance with a fourth embodiment of the invention. The aerosol-generating article 6 of the fourth embodiment is generally the same as the aerosol-generating article 3 of the third embodiment and like-for-like reference numerals are used where appropriate. However, the aerosol-generating article 6 of the fourth embodiment does not comprise a mouthpiece element 42 at a location downstream of the tubular element 600. Instead, the tubular element 600 of FIG. 6 extends all the way from the downstream end of the aerosol-forming substrate 12 to the mouth end 20 of the aerosol-generating article 6. The downstream section 14 of the aerosol-generating article 6 in FIG. 6 is therefore entirely formed by the tubular element 600.
[0350] Furthermore, in the embodiment of FIG. 6, the first end wall 604 of the tubular element 600 is not disposed adjacent to the downstream end of the aerosol-forming substrate 12. Instead, the first end wall 604 of the tubular element 600 is disposed at the mouth end 20 of the aerosol-generating article 6. The first end wall 604 delimits and opening 605, which permits airflow between the cavity 606 and the exterior of the tubular element 600. The opening 605 is configured so that one or both of air and aerosol may flow from the cavity 606 through the opening 605b to the exterior of the aerosol-generating article 6.
[0351] FIG. 7 shows an aerosol-generating article 7 in accordance with a fifth embodiment of the invention. The aerosol-generating article 7 of the fifth embodiment is generally the same as the aerosol-generating article 6 of the fourth embodiment and like-for-like reference numerals are used where appropriate. However, the aerosol-generating article 7 of the fifth embodiment now comprises a mouthpiece element in the form of a hollow tube 742 at a location downstream of the tubular element 700. The tubular element 700 of FIG. 7 therefore extends all the way to the upstream end of this hollow tube 742. The downstream section 14 of the aerosol-generating article 6 in FIG. 6 is therefore defined by the tubular element 700 and the hollow tube 742.
[0352] FIG. 8 shows an aerosol-generating article 8 in accordance with a sixth embodiment of the invention. The aerosol-generating article 8 of the sixth embodiment is generally the same as the aerosol-generating article 1 of the first embodiment and like-for-like reference numerals are used where appropriate.
[0353] However, in the embodiment of FIG. 8, the tubular element 800 is not in contact with the first element 11 comprising the aerosol-generating substrate 12. Instead, an empty space 850 exists between the downstream end of the first element 11 and the first end wall 804 at the upstream end 801 of the tubular element 800. Consequently, in the embodiment of FIG. 8, the first end wall 804 of the tubular element 800 does not provide a barrier which is in contact with the aerosol-generating substrate 12 for restricting movement of the aerosol-generating substrate 12. However, the empty space 850 does provide a region in which any loose particles or pieces from the aerosol-generating substrate 12 may congregate during use of the aerosol-generating article 8. The first end wall 804 may, with the assistance of gravity, prevent such loose particles or pieces from moving further downstream within the aerosol-generating article 8.
[0354] FIG. 9 shows an aerosol-generating article 9 not in accordance the invention. The aerosol-generating article 9 has similarities with the aerosol-generating article 1 of the first embodiment of the invention in FIG. 1, and like-for-like reference numerals are used where appropriate. However, the aerosol-generating article 9 of FIG. 9 does not comprise a tubular element in accordance with the invention. In particular, in contrast to the aerosol-generating article 1 of FIG. 1, the aerosol-generating article 9 of FIG. 9 does not comprise a tubular element 100 between the first element 100 and the mouthpiece element 42. Instead, the aerosol-generating article 9 of FIG. 9 comprises two hollow acetate tubes between the first element 100 and the mouthpiece element 42. These are a first hollow acetate tube 980 located immediately downstream of the first element 11 and a second hollow acetate tube 990 located immediately downstream of the first hollow acetate tube 980.
[0355] FIGS. 10A and 10B depict air flow fields generated in a Computational Fluid Dynamics (CFD) simulation comparing an aerosol-generating article in accordance with FIG. 1 comprising tubular element (hereinafter referred to as Example A) with an aerosol-generating article in accordance with FIG. 9 comprising two known hollow acetate tubes (hereinafter referred to as Comparative Example A). FIG. 10A shows the air flow fields 0.25 seconds into a simulated puff, and FIG. 10B shows the air flow fields 1 second into a simulated puff.
[0356] The aerosol-generating article of Example A consists of the following elements placed adjacent to one another starting from the upstream end of the aerosol-generating article: a cylindrical plug of cellulose acetate (length: 5 millimetres); an aerosol-forming substrate formed of a gathered crimped sheet of tobacco surrounding a susceptor (length: 12 millimetres); a tubular element having a folded end portion forming a first end wall adjacent to the aerosol-forming substrate (length: 16 millimetres); and a mouth end plug of cellulose acetate (length: 12 millimetres).
[0357] The aerosol-generating article of Comparative Example A consists of like-for-like elements to the article of Example A except that the tubular element has been replaced with two hollow acetate tubes of a combined equivalent length. Therefore, the aerosol-generating article of Comparative Example A consists of the following elements placed adjacent to one another starting from the upstream end of the aerosol-generating article: a cylindrical plug of cellulose acetate (length: 5 millimetres); an aerosol-forming substrate formed of a gathered crimped sheet of tobacco surrounding a susceptor (length: 12 millimetres); a first hollow acetate tube (length: 8 millimetres); a second hollow acetate tube (length: 8 millimetres); and a mouth end plug of cellulose acetate (length: 12 millimetres).
[0358] A single line of ventilation providing a ventilation level of 40 percent is provided around the tubular element of Example A and is disposed 5 millimetres from the downstream end of the tubular element. A single line of ventilation providing a ventilation level of 40 percent is also provided around the second hollow acetate tube of Comparative Example A and is disposed 5 millimetres from the downstream end of the second hollow acetate tube.
[0359] As can be seen from FIG. 10A, after 0.25 seconds of a puff, mixing of air drawn through the aerosol-forming substrate with fresh air drawn through the ventilation holes is noticeably more prominent in Example A than in Comparative Example A. Higher speed values are also more notable in Example A when compared with Comparative Example A.
[0360] This phenomenon develops further as the puff progresses in time, as illustrated by FIG. 10B. In particular, in FIG. 10B, after 1 second of a puff, jet instabilities and further velocity increases can be seen with Example A, which are not present in Comparative Example A. Such jet instabilities may improve the mixing of hot air drawn through the aerosol-forming substrate with fresh air drawn through the ventilation holes. This may lead to more favourable conditions for nucleation and growth of aerosol particles within the tubular element, when compared to that of the hollow acetates tube of Comparative Example A. Without wishing to be bound by theory, it is thought that such favourable conditions are particularly promoted in Example A through the combined use of the first end wall of the tubular element and the ventilation line disposed around the tubular element. In particular, the first end wall of the tubular element can provide a partial restriction of where air can flow into and out of the tubular element. This partial restriction, when combined with presence of ventilation downstream of the restriction, appears to be particularly effective at promoting the mixing of hot air drawn through the aerosol-forming substrate with fresh air drawn through the ventilation holes.
[0361] FIGS. 11A and 11B depict air temperature fields generated in a Computational Fluid Dynamics (CFD) simulation, and provide a comparison of these for the aerosol-generating article of Example A with the aerosol-generating article of Comparative Example A. FIG. 11A shows the air temperature fields 0.25 seconds into a simulated puff, and FIG. 10B shows the air temperature fields 1 second into a simulated puff. As can be clearly seen in FIGS. 11A and 11B, a more evenly distributed and higher temperature is achieved within the tubular element of Example A when compared with the hollow acetate tubes of Comparative Example A. This is noticeable after 0.25 seconds of a puff, and also noticeable after 1 second of a puff.
[0362] FIG. 12 shows a schematic side sectional view of the tubular element of FIG. 1, and illustrates various dimensions of the tubular element. In particular, a first double ended arrow 1201 is included in FIG. 12 to illustrate the internal diameter of the cavity 106 of the tubular body, a second double ended arrow 1202 is included in FIG. 12 to illustrate the outer diameter of the tubular body, and a third double ended arrow 1203 is included in FIG. 12 to illustrate the diameter of the opening 105 of the first end wall. These diameters may be used to calculate corresponding areas, as measured perpendicular to the longitudinal direction of the tubular element. In particular, the internal diameter of the cavity 106 can be used to calculate the area of the cavity, as measured perpendicular to the longitudinal direction of the tubular element.
[0363] In FIG. 12, the tubular element 100 has an external diameter 1202 of about 7.25 millimetres, and an internal diameter 1201 of about 6.5 millimetres. Thus, a thickness of a peripheral wall of the tubular body 103 is about 0.375 millimetres. The diameter 1203 of the opening is about 2.2 millimetres. Thus, the area of the opening in FIG. 12 is about 3.8 millimetres squared. The area of the cavity defined by the internal diameter 1201 of the tubular body is about 33.2 millimetres squared. The area corresponding to the outer diameter 1202 of the tubular body is about 41.3 millimetres squared.
[0364] The following table, Table 1, details the measured yields of Nicotine and Glycerol produced by the following four aerosol-generating articles when subjected to identical smoking tests: Example B, Example C, and Comparative Example 1.
[0365] The aerosol-generating article of Example B consists of the following elements placed adjacent to one another starting from the upstream end of the aerosol-generating article: a cylindrical plug of an aerosol-forming substrate; a tubular element having a folded end portion forming a first end wall adjacent to the aerosol-forming substrate, the first end wall delimiting an opening; and a mouth end plug of cellulose acetate. The opening of the first end wall has a diameter of 1.5 millimetres.
[0366] The aerosol-generating article of Example C is identical to the aerosol-generating article of Example B, except that the opening of the first end wall has a diameter of 3 millimetres.
[0367] The aerosol-generating article of Comparative Example 1 is identical to the aerosol-generating article of Example B, except that the tubular element does not have a folded end portion forming a first end wall. The tubular element is instead a hollow tube having a constant cross section along its length with an empty internal cavity.
TABLE-US-00001 TABLE 1 Type of Aerosol- Comparative generating Article Example 1 Example B Example C Nicotine yield 1073 1254 1128 (g/stick) Glycerol yield 4240 5768 4759 (g/stick)
As illustrated by Table 1, both Example B and Example C were found to produce aerosols having nicotine yields and glycerol yields noticeably higher than those of Comparative Example 1. Example B was found to produce particularly high yields for both nicotine and glycerol in comparison to Comparative Example 1. It has also been noted by the inventors that the glycerol yield per puff peaked and plateaued at an earlier puff in the smoking cycle for an aerosol-generating article with a tubular element having a 2 millimetre diameter opening when compared to an identical aerosol-generating article having a tubular element with a 3 millimetre diameter opening.
