Cigarette filter to reduce smoke deliveries in later puffs

Abstract

A smoking article having a tobacco rod adapted to produce mainstream smoke, and a filter having an upstream end portion and a downstream end portion, and wherein the filter is arranged to receive mainstream smoke at the upstream end portion. The filter includes a first filter segment of low particulate efficiency at the upstream end portion; a channeled flow segment adjacent to the first filter segment, the channeled flow segment including a flow channel establishing a substantial portion of a predetermined resistance to draw of the smoking article; a mouthpiece filter segment of low particulate efficiency at the downstream end portion; and a tubular body segment at least partially defining a portion of a cavity between the mouthpiece filter and the channeled flow segment. Tipping paper attaches the filter with the tobacco rod and includes an air-admissible ventilation zone at a location along the tubular body segment.

1 . A smoking article comprising:
 a tobacco rod adapted to produce mainstream smoke;   a filter having an upstream end portion and a downstream end portion, the filter arranged to receive mainstream smoke at the upstream end portion, the filter comprising:
 a first filter segment of low particulate efficiency at the upstream end portion; 
 a channeled flow segment at a location downstream of the first filter segment, the channeled flow segment including a flow channel establishing a substantial portion of a predetermined resistance to draw of the smoking article; 
 a mouthpiece filter segment of low particulate efficiency at the downstream end portion; and 
 a tubular body segment at least partially defining a portion of a cavity between the mouthpiece filter and the flow channel of the channeled flow segment; and 
   tipping paper attaching the filter with the tobacco rod and including an air-admissible ventilation zone at a location along the tubular body segment.   
     
     
         2 . The smoking article of  claim 1 , wherein the channeled flow segment is spaced from the mouthpiece filter segment by a distance sufficient to reduce impaction of a mainstream smoke component upon an upstream end portion of the mouthpiece filter. 
     
     
         3 . The smoking article of  claim 1 , wherein the air-admissible ventilation zone comprises a row of perforations extending through the tipping paper and the tubular body segment. 
     
     
         4 . The smoking article of  claim 1 , wherein the ventilation zone is spaced from the mouthpiece filter segment by a distance sufficient to promote mixing of air drawn through the ventilation zone and mainstream smoke drawn from the tobacco rod. 
     
     
         5 . The smoking article of  claim 1 , wherein at least one of the first filter segment and the mouthpiece filter segments comprises cellulose acetate tow of low resistance to draw. 
     
     
         6 . The smoking article of  claim 1 , wherein the flow channel is coaxially positioned within the channeled flow segment. 
     
     
         7 . The smoking article of  claim 1 , wherein the flow channel is in an outer periphery of the channeled flow segment. 
     
     
         8 . The smoking article of  claim 1 , wherein the flow channel has a relatively constant diameter extending from an upstream end to a downstream end of the channeled flow segment. 
     
     
         9 . The smoking article of  claim 1 , wherein the flow channel is a spiral channel. 
     
     
         10 . The smoking article of  claim 1 , wherein the flow channel includes a sintered porous plastic. 
     
     
         11 . The smoking article of  claim 1 , wherein the channel flow segment is a a plate having at least one orifice. 
     
     
         12 . The smoking article of  claim 11 , wherein the plate has a thickness of less than 2 mm and the at least one orifice has a diameter of 0.2 mm to 0.6 mm. 
     
     
         13 . A filter having an upstream end portion and a downstream end portion and arranged to receive mainstream smoke at the upstream end portion, the filter comprising:
 a first filter segment of low particulate efficiency at the upstream end portion;   a channeled flow segment at a location downstream of the first filter segment, the channeled flow segment including a flow channel establishing a substantial portion of a predetermined resistance to draw of the smoking article;   a mouthpiece filter segment of low particulate efficiency at the downstream end portion; and   a tubular body segment at least partially defining a portion of a cavity between the mouthpiece filter and the flow channel of the channeled flow segment.   
     
     
         14 . The filter of  claim 13 , wherein the channeled flow segment is spaced from the mouthpiece filter segment by a distance sufficient to reduce impaction of a mainstream smoke component upon an upstream end portion of the mouthpiece filter. 
     
     
         15 . The filter of  claim 13 , wherein at least one of the first filter segment and the mouthpiece filter segments comprises cellulose acetate tow of low resistance to draw. 
     
     
         16 . The filter of  claim 13 , wherein the flow channel is coaxially positioned within the channeled flow segment. 
     
     
         17 . The filter of  claim 13 , wherein the flow channel is in an outer periphery of the channeled flow segment. 
     
     
         18 . The filter of  claim 13 , wherein the flow channel has a relatively constant diameter extending from an upstream end to a downstream end of the channeled flow segment. 
     
     
         19 . The filter of  claim 13 , wherein the flow channel is a spiral channel. 
     
     
         20 . The filter of  claim 13 , wherein the flow channel includes a sintered porous plastic. 
     
     
         21 . A method of reducing total FTC tar delivery of a smoking article by drawing mainstream smoke during each puff through an upstream, channeled filter segment and a downstream filter portion having a ventilation zone, said upstream channeled filter segment accumulating tar as smoking progresses through a puff count such that delivered FTC tar is decreased in the later puffs of the puff counts when compared to a conventional cigarette.