Smoking article filter with annular restrictor and downstream ventilation
A smoking article includes a tobacco rod adapted to produce mainstream smoke, and a filter having an upstream end portion and a downstream end portion. The filter includes a ventilated cavity and a flow restrictor segment having an impermeable insert at least partially surrounded by a tubular segment of an air transmissive material upstream of the cavity. In an embodiment, the tubular segment at least partially defines the cavity.
1. A smoking article comprising:
a tobacco rod adapted to produce mainstream smoke;
a filter operative with said tobacco rod, said filter having an upstream end portion and a downstream end portion, said filter comprising:
a central cavity located between said upstream end portion and said downstream end portion;
a flow restricting filter segment located upstream of said cavity and including an impermeable insert surrounded by a tubular segment of an air transmissive material; and
a ventilation zone at a location along said cavity and downstream of said flow restricting segment, said ventilation zone in communication with said cavity.
2. The smoking article of claim 1 , wherein the tubular segment has a length equal to or exceeding a length of the insert.
3. The smoking article of claim 1 , wherein said air transmissive material is selected from the group consisting of a hollow acetate tube, carbon on tow, carbon paper, thick and/or heavy paper, and combinations thereof.
4. The smoking article of claim 1 , wherein said insert is in a condition of having been plunged into said tubular segment.
5. The smoking article of claim 1 , wherein said tubular segment at least partially defines said cavity.
6. The smoking article of claim 1 , wherein said insert is fully contained within said tubular segment.
7. The smoking article of claim 1 , wherein said insert has a sliding fit with said tubular segment.
8. The smoking article of claim 1 , wherein said insert is coextensive with the filter length and/or there is no filtering material between the flow restricting filter segment and a downstream end of the tobacco rod.
9. The smoking article of claim 1 , wherein said filter and tobacco rod are attached with tipping paper and wherein said ventilation zone is defined by at least one row of perforations in said tipping paper.
10. The smoking article of claim 1 , wherein said smoking article includes an optional first filter plug upstream of said flow restricting filter segment and a second filter plug at a mouth end of said filter.
11. The smoking article of claim 10 , wherein at least one of said first filter plug segment and said second filter plug segment comprises cellulose acetate tow of about 5 denier to about 25 denier per filament.
12. The smoking article of claim 1 , wherein the predetermined resistance-to-draw of said smoking article is approximately 40 millimeters water or above.
13. The smoking article of claim 1 , wherein said insert is formed from a material selected from high density polyethylene, polypropylene, nylon, compressed or extruded cellulosic material, closed cell foams, and/or combinations thereof.
14. The smoking article of claim 1 , wherein said insert includes at least one flavorant.
15. The smoking article of claim 1 , wherein said insert has end-to-end symmetry.
16. The smoking article of claim 1 , wherein said insert includes an impermeable end wall.
17. The smoking article of claim 1 , wherein said insert is a solid plug press fitted into a hollow acetate tube.
18. The smoking article of claim 1 , wherein said insert is injection molded.
19. The smoking article of claim 1 , wherein said smoking article has a ventilation level at least about 25%.
20. The smoking article of claim 1 , wherein said smoking article has a ventilation level at least about 50% to about 90%.