Smoking article with valve

Abstract

A smoking article having a cylinder of smoking material, a hollow tube within the cylinder of smoking material, and a filter attached to the cylinder of smoking material. The filter includes an upstream segment containing an aerosol former, a downstream segment containing a sorbent material, and a valve positioned between the upstream segment and the downstream segment. The valve has a first position in which the valve is closed and a second position in which the valve is open and allows the passage of smoke through the filter.

1 . A smoking article comprising:
 a cylinder of smoking material;   a hollow tube within the cylinder of smoking material; and   a filter attached to the cylinder of smoking material, the filter comprising:
 an upstream segment containing an aerosol former; 
 a downstream segment containing a sorbent material; and 
 a valve positioned between the upstream and the downstream segments, wherein the valve includes a first position in which the valve is closed, and a second position in which the valve is open and allows the passage of smoke through the filter. 
   
   
   
       2 . The smoking article of  claim 1 , wherein the valve is designed to open at a minimum operational pressure and remains open as long as the minimum operational pressure is maintained; or the valve has a predetermined range of operational pressures, and the valve opens at a minimum operational pressure and closes if the operational pressure is higher than a maximum operational pressure. 
   
   
       3 . The smoking article of  claim 1 , wherein the sorbent material is an activated carbon material. 
   
   
       4 . The smoking article of  claim 1 , wherein the upstream and the downstream segments are cellulose acetate tow. 
   
   
       5 . The smoking article of  claim 2 , wherein the sorbent material comprises an activated carbon composition mixed with cellulose acetate fibers. 
   
   
       6 . The smoking article of  claim 1 , wherein the aerosol former is selected from a group comprising glycerin, propylene, glycol, triacetin, propylene carbonate and triethyl citrate. 
   
   
       7 . The smoking article of  claim 1 , wherein the upstream segment is a fibrous material; and the downstream segment of sorbent material is between a pair of segments of cellulose acetate tow. 
   
   
       8 . The smoking article of  claim 7 , wherein the fibrous material is selected from a group comprising crimped paper, modified celluloses, carbon felts and foams, or encapsulated aerosol formers. 
   
   
       9 . The smoking article of  claim 1 , further comprising a plurality of ventilation holes within the filter on a downstream side of the valve. 
   
   
       10 . The smoking article of  claim 1 , further comprising a plurality of ventilation holes within the filter on an upstream side of the valve. 
   
   
       11 . A smoking article comprising:
 a cylinder of smoking material;   a hollow tube within the cylinder of smoking material; and   a filter attached to the cylinder of smoking material, the filter having a segment containing an aerosol former, a valve having a first position in which the valve is closed, and a second position in which the valve is open and allows the passage of smoke through the filter, and at least one segment of filtering material.   
   
   
       12 . The smoking article of  claim 11 , wherein the valve is designed to open at a minimum operational pressure and remains open as long as the minimum operational pressure is maintained. 
   
   
       13 . The smoking article of  claim 11 , wherein the valve has a pre-determined range of operational pressures, and the valve opens at a minimum operational pressure and closes if the operational pressure is higher than a maximum operational pressure. 
   
   
       14 . The smoking article of  claim 11 , further comprising a plurality of ventilation holes within the filter on a downstream side of the valve; or a plurality of ventilation holes within the filter on an upstream side of the valve 
   
   
       15 . A filter for a smoking article comprising:
 an upstream segment containing an aerosol former;   a downstream segment containing a sorbent material; and   a valve positioned between the upstream segment and the downstream segments, wherein the valve includes a first position in which the valve is closed, and a second position in which the valve is open and allows the passage of smoke through the filter.   
   
   
       16 . The filter of  claim 15 , wherein the valve is designed to open at a minimum operational pressure and remains open as long as the minimum operational pressure is maintained. 
   
   
       17 . The filter of  claim 15 , wherein the valve has a pre-determined range of operational pressures, and the valve opens at a minimum operational pressure and closes if the operational pressure is higher than a maximum operational pressure. 
   
   
       18 . The filter of  claim 15 , wherein the smoking article is an electrically heated smoking system. 
   
   
       19 . The filter of  claim 15 , wherein the smoking article comprises a cigarette holder and a cigarette. 
   
   
       20 . A method of making a smoking article, comprising:
 forming a tobacco rod portion of the smoking article by placing smoking material between a hollow tube and an outer layer of wrapper paper;   forming a filter portion of the smoking article having a plurality of segments comprising an upstream segment containing an aerosol former, a valve having a first position in which the valve is closed, and a second position in which the valve is open and allows the passage of smoke through the filter, and at least one filtering material segment; and   joining said tobacco rod portion in end-to-end relationship with the filter portion.