Aerosol-generating device with substrate sensor

Abstract

An aerosol-generating device is provided, including: a cavity configured to receive an aerosol-forming substrate; an airflow channel through the cavity; a substrate sensor arranged at a base of the cavity, the substrate sensor being a pH sensor and being configured to detect a pH value of aerosol being drawn through the airflow channel indicative of a depletion degree of the aerosol-forming substrate; and a controller configured to generate a signal, based upon an output of the substrate sensor, if the depletion degree of the aerosol-forming substrate falls under a predetermined threshold, the signal being indicative of the depletion degree of the aerosol-forming substrate. An aerosol-generating system including the aerosol-generating device is also provided. A method for detecting a depletion degree of an aerosol-forming substrate of an aerosol-generating article or of a cartridge in the aerosol-generating device is also provided.

1 .- 17 . (canceled) 
     
     
         18 . An aerosol-generating device, comprising:
 a cavity configured to receive an aerosol-forming substrate;   an airflow channel through the cavity;   a substrate sensor arranged at a base of the cavity, wherein the substrate sensor is a pH sensor and is configured to detect a pH value of aerosol being drawn through the airflow channel indicative of a depletion degree of the aerosol-forming substrate; and   a controller configured to generate a signal, based upon an output of the substrate sensor, if the depletion degree of the aerosol-forming substrate falls under a predetermined threshold, wherein the signal is indicative of the depletion degree of the aerosol-forming substrate.   
     
     
         19 . The aerosol-generating device according to  claim 18 , wherein the substrate sensor has a measurement range of between 2 pH and 10 pH. 
     
     
         20 . The aerosol-generating device according to  claim 18 , wherein the substrate sensor has a measurement range of between 3 pH and 9 pH. 
     
     
         21 . The aerosol-generating device according to  claim 18 , wherein the substrate sensor has a measurement range of between 5 pH and 8 pH. 
     
     
         22 . The aerosol-generating device according to  claim 18 , wherein the substrate sensor has a measurement accuracy at pH 7 of ±0.02 pH. 
     
     
         23 . The aerosol-generating device according to  claim 18 , wherein the substrate sensor has a measurement accuracy at pH 7 of ±0.01 pH. 
     
     
         24 . The aerosol-generating device according to  claim 18 , wherein the substrate sensor has a drift at pH 7 of less than 0.05 pH per day. 
     
     
         25 . The aerosol-generating device according to  claim 18 , wherein the substrate sensor is arranged in or adjacent the base of the cavity. 
     
     
         26 . The aerosol-generating device according to  claim 18 , wherein the signal is one or more of a signal of a user interface, a light emitting signal, a sound signal, and a vibration signal. 
     
     
         27 . The aerosol-generating device according to  claim 18 , wherein the controller is further configured to end operation of the aerosol-generating device after a predetermined time or a predetermined number of puffs of a user, if the depletion degree of the aerosol-forming substrate is under the predetermined threshold. 
     
     
         28 . The aerosol-generating device according to  claim 18 , wherein the depletion degree of the aerosol-forming substrate is a pH value of aerosol being drawn through the airflow channel. 
     
     
         29 . The aerosol-generating device according to  claim 18 ,
 further comprising an activation button,   wherein the substrate sensor is further configured to start detecting the depletion degree of the aerosol-forming substrate after a predetermined time after pressing of the activation button or after a predetermined number of puffs of a user after pressing of the activation button.   
     
     
         30 . The aerosol-generating device according to  claim 29 , wherein the substrate sensor is further configured to detect the depletion degree of the aerosol-forming substrate continuously during operation of the aerosol-generating device or close to an estimated depletion of the aerosol-forming substrate. 
     
     
         31 . The aerosol-generating device according to  claim 30 , wherein the depletion estimation is based upon the predetermined time after pressing of the activation button or upon the predetermined number of puffs of a user after pressing of the activation button. 
     
     
         32 . The aerosol-generating device according to  claim 18 , wherein the airflow channel passes between side walls of an aerosol-forming substrate and side walls that define the cavity. 
     
     
         33 . The aerosol-generating device according to  claim 18 , wherein the substrate sensor is arranged to face an upstream end of the aerosol-forming substrate. 
     
     
         34 . An aerosol-generating system comprising an aerosol-generating device according to  claim 18  and one of an aerosol-generating article comprising an aerosol-forming substrate and a cartridge comprising liquid aerosol-forming substrate. 
     
     
         35 . A method for detecting a depletion degree of an aerosol-forming substrate of an aerosol-generating article or of a cartridge in an aerosol-generating device according to  claim 18 , the method comprising detecting, by the substrate sensor, a pH value of aerosol being drawn through the airflow channel indicative of a depletion degree of the aerosol-forming substrate.