Aerosol provision system with variable aerosol stream concentration

Abstract

An aerosol provision system ( 1 ) including at least an aerosol generator ( 48 ) for generating an aerosol from an aerosol-generating material ( 44 ) in an aerosol-generating region ( 45 ); a first air pathway ( 52 ) passing through the aerosol generation region ( 45 ); a second air pathway ( 53 ) not passing through the aerosol generation region ( 45 ); and an adjustment mechanism ( 170 ) configured to vary the ratio of the resistance-to-draw of the first air pathway ( 52 ) to the resistance-to-draw of the second air pathway ( 53 ) based upon a draw strength of a user inhalation.

1 . An aerosol provision system comprising:
 an aerosol generator for generating an aerosol from an aerosol-generating material in an aerosol-generating region;   a first air pathway passing through the aerosol generation region;   a second air pathway not passing through the aerosol generation region; and   an adjustment mechanism configured to vary the ratio of the resistance-to-draw of the first air pathway to the resistance-to-draw of the second air pathway based upon a draw strength of a user inhalation.   
     
     
         2 . The aerosol provision system of  claim 1 , wherein the adjustment mechanism is configured to vary the resistance-to-draw of the first air pathway. 
     
     
         3 . The aerosol provision system of  claim 1 , wherein the adjustment mechanism is configured to vary the resistance-to-draw of the second air pathway. 
     
     
         4 . The aerosol provision system of  claim 1 , wherein the adjustment mechanism is configured to provide a first ratio of the resistance-to-draw of the first air pathway to the resistance-to-draw of the second air pathway when the draw strength of the user inhalation is a first value; and
 wherein the adjustment mechanism is configured to provide a second ratio of the resistance-to-draw of the first air pathway to the resistance-to-draw of the second air pathway when the draw strength of the user inhalation is a second value which is different to the first value.   
     
     
         5 . The aerosol provision system of  claim 4 , wherein the first ratio is greater than the second ratio when the first value is greater than the second value. 
     
     
         6 . The aerosol provision system of  claim 1 , wherein the resistance-to-draw of the first air pathway is determined by the cross-section of the narrowest section of the first air pathway and the resistance-to-draw of the second air pathway is determined by the cross-section of the narrowest section of the second air pathway, and wherein the adjustment mechanism is configured to vary the ratio of the resistance-to-draw of the first air pathway to the resistance-to-draw of the second air pathway by varying the cross-section of at least one of the first air pathway and the second air pathway. 
     
     
         7 . The aerosol provision system of  claim 1 , wherein the adjustment mechanism comprises a valve provided in the second air pathway and configured to restrict air flow when the draw strength of a user inhalation exceeds a threshold value. 
     
     
         8 . The aerosol provision system of  claim 7 , wherein the valve is configured to prevent the flow of air along the second air pathway when the draw strength of the user inhalation exceeds the threshold value. 
     
     
         9 . The aerosol provision system of  claim 1 , wherein the first air pathway and second air pathway are fluidly coupled at their downstream ends to a common airflow pathway comprising a mouthpiece outlet through which a user inhales in use. 
     
     
         10 . The aerosol provision system of  claim 1 , wherein the adjustment mechanism is electronically controlled, and wherein the aerosol provision system comprises a sensor configured to estimate the draw strength of the user inhalation and a controller configured to control the adjustment mechanism. 
     
     
         11 . The aerosol provision system of  claim 10 , wherein the controller is configured to further control the adjustment mechanism based on a user input. 
     
     
         12 . The aerosol provision system of  claim 11 , wherein controller is configured to select a discrete mode of operation based on the user input, where the controller is configured to decrease the ratio of the resistance-to-draw of the first pathway to the resistance-to-draw of the second pathway in comparison to a normal mode to reduce a visibility of an aerosol produced by the aerosol generator. 
     
     
         13 . A method of controlling an aerosol provision system comprising an aerosol generator for generating an aerosol from an aerosol-generating material in an aerosol-generating region, and a first air pathway passing through the aerosol generation region, a second air pathway not passing through the aerosol generation region, the method comprising:
 providing an adjustment mechanism configured to vary the ratio of the resistance-to-draw of the first air pathway to the resistance-to-draw of the second air pathway based upon a draw strength of a user inhalation; and   adjusting the adjustment mechanism to vary the ratio of the resistance-to-draw of the first pathway to the resistance-to-draw of the second pathway.   
     
     
         14 . The method of  claim 13 , wherein adjusting the adjustment mechanism to vary the ratio of the resistance-to-draw of the first pathway to the resistance-to-draw of the second pathway comprises:
 estimating the draw strength of the user inhalation using a sensor; and   controlling the adjustment mechanism based on the estimated draw strength using a controller.   
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . An aerosol provision device for use with an aerosol generating article comprising aerosol generating material, which together form an aerosol provision system, wherein the aerosol provision system comprises an aerosol generator for generating an aerosol from an aerosol-generating material in an aerosol-generating region, a first air pathway passing through the aerosol generation region, a second air pathway not passing through the aerosol generation region, and an adjustment mechanism configured to vary the ratio of the resistance-to-draw of the first air pathway to the resistance-to-draw of the second air pathway based upon a draw strength of a user inhalation, wherein the aerosol provision device comprises:
 circuitry configured to control the adjustment mechanism to cause the adjustment mechanism configured to vary the ratio of the resistance-to-draw of the first air pathway to the resistance-to-draw of the second air pathway based upon a draw strength of a user inhalation.   
     
     
         18 . The aerosol provision device of  claim 17 , wherein at least a part of the first air pathway is provided in the aerosol provision device and/or wherein at least a part of the second air pathway is provided in the aerosol provision device, and wherein the adjustment mechanism is provided in the aerosol provision device and is arranged to vary the ratio of the resistance-to-draw of the first air pathway to the resistance-to-draw of the second air pathway by varying the resistance-to-draw of the at least a part of the first air pathway and/or the resistance-to-draw of the at least a part of the second air pathway.