AEROSOL GENERATING ARTICLE COMPRISING A HOLLOW ROD OF AEROSOL GENERATING SUBSTRATE

Abstract

An aerosol-generating article is provided for producing an inhalable aerosol when heated, the aerosol-generating article including: a hollow cylindrical rod of aerosol-generating substrate; a wrapper circumscribing the hollow cylindrical rod; and a hollow tube extending along a longitudinal axis of the hollow cylindrical rod and defining a central airflow channel of the aerosol-generating article, the hollow tube including a plurality of openings extending through a wall of the hollow tube, such that the aerosol-generating substrate in the hollow cylindrical rod is in fluid communication with the central airflow channel through the plurality of openings, and such that a ratio between a cumulative cross-sectional area of the plurality of openings and a cross-sectional area of the central airflow channel is from about 0.042 to about 0.672.

Claims

1 -13. (canceled)

14. An aerosol-generating article for producing an inhalable aerosol when heated, the aerosol-generating article comprising: a hollow cylindrical rod of aerosol-generating substrate; a wrapper circumscribing the hollow cylindrical rod; and a hollow tube extending along a longitudinal axis of the hollow cylindrical rod and defining a central airflow channel of the aerosol-generating article, the hollow tube comprising a plurality of openings extending through a wall of the hollow tube, such that the aerosol-generating substrate in the hollow cylindrical rod is in fluid communication with the central airflow channel through the plurality of openings, wherein a ratio between a cumulative cross-sectional area of the plurality of openings and a cross-sectional area of the central airflow channel is from about 0.042 to about 0.672.

15. The aerosol-generating article according to claim 14, wherein at least one opening of the plurality of openings comprises at least a first row of openings spaced about a circumference of the hollow tube at a predetermined distance from a first end of the hollow tube.

16. The aerosol-generating article according to claim 15, wherein the at least one opening further comprises at least a second row of openings spaced about the circumference of the hollow tube, the second row of openings being longitudinally spaced from the first row of openings by at least about 1 cm.

17. The aerosol-generating article according to claim 14, wherein the plurality of openings are arranged helically about an outer surface of the hollow tube.

18. The aerosol-generating article according to claim 14, wherein an outer diameter of the hollow tube is from about 2.0 mm to about 2.5 mm.

19. The aerosol-generating article according to claim 14, wherein an equivalent diameter of an opening among the plurality of openings is from about 0.5 mm to about 0.7 mm.

20. The aerosol-generating article according to claim 14, wherein a thickness of the hollow tube is from about 0.4 mm to about 1 mm.

21. The aerosol-generating article according to claim 14, wherein the hollow tube has a resistance-to-draw (RTD) of at least about 60 mm H.sub.2O.

22. The aerosol-generating article according to claim 14, wherein the at least one opening has a resistance-to-draw (RTD) less than 50 percent of the RTD of the hollow tube.

23. An aerosol-generating system, comprising: an aerosol-generating article and an electrically operated aerosol-generating device, the electrically operated aerosol-generating device comprising a heater and an elongate heating chamber configured to receive the aerosol-generating article such that the aerosol-generating article is heated in the elongate heating chamber, and the aerosol-generating article comprising: a hollow cylindrical rod of aerosol-generating substrate, a wrapper circumscribing the hollow cylindrical rod, and a hollow tube extending along a longitudinal axis of the hollow cylindrical rod and defining a central airflow channel of the aerosol-generating article, the hollow tube comprising at least one opening extending through a wall of the hollow tube, such that the aerosol-generating substrate in the hollow cylindrical rod is in fluid communication with the central airflow channel through the at least one opening.

24. The aerosol-generating system according to claim 23, wherein a cross-sectional surface area of the central airflow channel is from about 3.14 mm.sup.2 to about 4.52 mm.sup.2, and wherein a cross-sectional area of the at least one opening is from about 0.19 mm.sup.2 to about 0.38 mm.sup.2.

25. The aerosol-generating system according to claim 23, wherein the heater comprises a substantially cylindrical, elongate heating element, and the elongate heating chamber is disposed about a circumferential, longitudinal surface of the heater.

26. The aerosol-generating system according to claim 23, further comprising insulation arranged between the heating chamber and an exterior of the system configured to reduce heat loss from the aerosol-generating substrate when the aerosol-generating substrate is heated.

Description

[0068] The invention will now be further described with reference to the drawing of FIG. 1, which shows a schematic longitudinal cross-sectional view of an aerosol generating article in accordance with the present invention.

[0069] The aerosol generating article 10 shown in FIG. 1 comprises a hollow cylindrical rod 12 of aerosol generating substrate circumscribed by a paper wrapper 14. The rod 12 comprises a plurality of strands or strips of homogenised tobacco material substantially randomly arranged within the rod. The strands have a width of about 1.4 millimetres and a length of at least about 10 millimetres. An external diameter of the rod 12 is about 7.4 millimetres. An internal diameter of the rod is about 4.2 millimetres. A length of the rod 12 is about 50 millimetres.

[0070] Further, the aerosol generating article 10 comprises a hollow tube 14 made of a polymeric material extending along a longitudinal axis of the rod and defining a central airflow channel 16 of the aerosol generating article. The hollow tube 14 has an external diameter of about 4.2 millimetres and a wall thickness of about 1 millimetre. Thus, an internal diameter of the hollow tube is about 2.2 millimetres, and a cross-sectional area of the central airflow channel is about 3.8 square millimetres.

[0071] The hollow tube comprises a plurality of openings 18 extending through the wall of the tube, which establish fluid communication between the aerosol generating substrate in the rod 12 and the central airflow channel 16. Each opening 18 has a diameter of about 0.6 millimetre, and a cross-section of about 0.28 square millimetres. Thus, a ratio between the area of the cross-section of each single opening 18 and the area of the cross-section of the central airflow channel 16 is about 0.073.

[0072] The openings 18 are provided as four pairs of openings located at diametrically opposed locations about the periphery of the hollow tube 14. Adjacent pairs of openings are longitudinally spaced about 9 millimetres from each other. The cumulative cross-sectional area of the eight openings 18 is about 2.24 square millimetres. Thus, a ratio between the cumulative cross-sectional area of the openings 18 and the area of the cross-section of the central airflow channel 16 is about 0.59.

[0073] At the downstream end, the aerosol generating article 10 comprises a filter 20. In use, the aerosol generating article 10 described above is received in an elongate heating chamber of an electrically operated aerosol generating device comprising a heater configured to supply heat to the aerosol generating article in the heating chamber. To this purpose, the heater may comprise a substantially cylindrical, elongate heating element, the heating chamber being disposed about a circumferential, longitudinal surface of the heater. The consumer draws on the mouth end of the aerosol generating article, and air is drawn into the aerosol generating article at the opposite end. The arrow in FIG. 1 indicates schematically a direction of flow of a mainstream airflow travelling along the central airflow channel 16.