# US 11,432,589 B2 · Electronic vapor provision system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,432,589 B2 - Document ID: US11432589B2 - Status: Granted - Kind: B2 - Application number: 16/478,725 - Filed: 2018-01-10 - Published: 2020-02-13 - Granted: 2022-09-06 - Earliest claimed: 2017-01-23 - Assignees: Nicoventures Trading Limited - Applicants: Nicoventures Trading Limited - Inventors: Kenny Otiaba; David Leadley - Web page: https://patentgrep.com/patent/US11432589B2 ## CPC - A24F 40/53: Monitoring, e.g. fault detection - A24F 40/46: Shape or structure of electric heating means - A24F 40/57: Temperature control - G01R 27/02: Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only G01R25/00) - H05B 1/0297: {Heating of fluids for non specified applications} - A24F 40/10: Devices using liquid inhalable precursors - A24F: SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES (inhaling appliances for medical purposes, shaped like cigars, cigarettes or pipes A61M15/06) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract An electronic vapor provision device includes a first electrical resistive heater for vaporizing a precursor material to generate vapor in an airflow for inhalation by a user and a second electrical resistive heater for vaporizing the precursor material and/or heating said airflow. The first electrical resistive heater has a first thermal coefficient of resistance which is less than a second thermal coefficient of resistance of the second electrical resistive heater. The device further includes a control system to monitor for a change in the resistance of at least the second electrical resistive heater. The second electrical resistance heater therefore serves both as a heater and as a temperature monitor. ## Claims ### Claim 1 An electronic vapor provision device comprising: a first electrical resistive heater for vaporizing a liquid precursor material to generate vapor in an airflow for inhalation by a user; a second electrical resistive heater for at least one of vaporizing the liquid precursor material or heating the airflow, wherein the first electrical resistive heater has a first thermal coefficient of resistance which is less than a second thermal coefficient of resistance of the second electrical resistive heater; a control system configured to monitor for a change in resistance of at least the second electrical resistive heater; and a wick for transferring the liquid from a reservoir to the first electrical resistive heater, wherein the second thermal coefficient of resistance is greater than 1×10−3 K−1 at room temperature, and wherein the control system is configured to monitor for a change in resistance indicating that at least a portion of the wick has dried out. ### Claim 2 An electronic vapor provision device comprising: a first electrical resistive heater for vaporizing a precursor material to generate vapor in an airflow for inhalation by a user; a second electrical resistive heater for at least one of vaporizing the precursor material or heating the airflow, wherein the first electrical resistive heater has a first thermal coefficient of resistance which is less than a second thermal coefficient of resistance of the second electrical resistive heater; and a control system configured to monitor for a change in resistance of at least the second electrical resistive heater, wherein the second thermal coefficient of resistance is greater than 1×10−3K−1 at room temperature, and wherein the control system is configured to monitor for a change in the resistance of at least the second electrical resistive heater by detecting a decrease in current after a predetermined time threshold. ### Claim 3 (depends on 2) The electronic vapor provision device of claim 2, wherein the first electrical resistive heater is a wire coil. ### Claim 4 (depends on 2) The electronic vapor provision device claim 2, wherein the second electrical resistive heater is a wire coil. ### Claim 5 (depends on 2) The electronic vapor provision device of claim 2, wherein the first electrical resistive heater comprises a first wire coil, and the second electrical resistive heater comprises a second wire coil, and wherein the first wire coil and the second wire coil are coaxial. ### Claim 6 (depends on 2) The electronic vapor provision device of claim 2, wherein the second thermal coefficient of resistance is greater than the first thermal coefficient of resistance by a factor of at least two. ### Claim 7 (depends on 2) The electronic vapor provision device of claim 2, wherein the first thermal coefficient of resistance is less than 1×10−3 K−1 at room temperature. ### Claim 8 (depends on 2) The electronic vapor provision device of claim 2, wherein the second thermal coefficient of resistance is greater than 2.5×10−3 K−1 at room temperature. ### Claim 9 (depends on 2) The electronic vapor provision device of claim 2, wherein the second electrical resistive heater is substantially made of titanium or nickel. ### Claim 10 (depends on 2) The electronic vapor provision device of claim 2, wherein the first electrical resistive heater is substantially made of nichrome. ### Claim 11 (depends on 2) The electronic vapor provision device of claim 2, wherein the first electrical resistive heater is electrically in parallel with the second electrical resistive heater. ### Claim 12 (depends on 2) The electronic vapor provision device of claim 2, wherein the first electrical resistive heater is electrically in series with the second electrical resistive heater. ### Claim 13 (depends on 2) The electronic vapor provision device of claim 2, wherein the first electrical resistive heater is configured to dissipate greater power than the second electrical resistive heater. ### Claim 14 (depends on 2) The electronic vapor provision device of claim 2, wherein the control system is configured to monitor for a change in the resistance of at least the second electrical resistive heater indicative of a significant rise in temperature. ### Claim 15 (depends on 2) The electronic vapor provision device of claim 2, wherein the electronic vapor provision device comprises a re-usable portion including the control system, and a disposable portion including the first electrical resistive heater and the second electrical resistive heater. ### Claim 16 (depends on 15) The electronic vapor provision device of claim 15, wherein the re-usable portion and the disposable portion are joined using two electrical contacts, representing positive and negative polarity. ### Claim 17 (depends on 16) The electronic vapor provision device of claim 16, wherein the control system is configured to monitor for a change in resistance of the disposable portion as a whole, including the second electrical resistive heater. ### Claim 18 (depends on 15) The electronic vapor provision device of claim 15, wherein the second electrical resistive heater is responsible for a majority of a temperature sensitivity of an electrical resistance of the disposable portion. ### Claim 19 (depends on 2) The electronic vapor provision device of claim 2, wherein the control system comprises a current sensor in combination with a controller. ### Claim 20 (depends on 2) The electronic vapor provision device of claim 2, wherein the electronic vapor provision device is configured to provide thermal contact between the first electrical resistive heater and the second electrical resistive heater. ### Claim 21 An electronic vapor provision device comprising: a first electrical resistive heater for vaporizing a precursor material to generate vapor in an airflow for inhalation by a user; a second electrical resistive heater for at least one of vaporizing the precursor material or heating the airflow, wherein the first electrical resistive heater has a first thermal coefficient of resistance which is less than a second thermal coefficient of resistance of the second electrical resistive heater; and a control system configured to monitor for a change in resistance of at least the second electrical resistive heater, wherein the second thermal coefficient of resistance is greater than 1×10−3K−1 at room temperature, and wherein the control system is configured to reduce or cut off a supply of power to at least one of the first electrical resistive heater or the second electrical resistive heater based on a change in the resistance of at least the second electrical resistive heater satisfying one or more predetermined criteria.