# US 11,998,060 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 11,998,060 B2 - Document ID: US11998060B2 - Status: Granted - Kind: B2 - Application number: 17/929,536 - Filed: 2022-09-02 - Published: 2023-04-06 - Granted: 2024-06-04 - Earliest claimed: 2017-01-23 - Assignees: Nicoventures Trading Limited - Applicants: Nicoventures Trading Limited - Inventors: Kenny Otiaba; David Leadley - Web page: https://patentgrep.com/patent/US11998060B2 ## 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 comprises: 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 having a first thermal coefficient of resistance; a second electrical resistive heater having a second thermal coefficient of resistance that is at least two times larger than the first thermal coefficient of resistance; a wick for transporting e-liquid from a reservoir to the first electrical resistive heater and the second electrical resistive heater; and a control system configured to monitor for a change in resistance of the second electrical resistive heater, wherein the first electrical resistive heater and the second electrical resistive heater are each mounted around the wick. ### Claim 2 (depends on 1) The electronic vapor provision device of claim 1, wherein the first electrical resistive heater comprises a first coil and the second electrical resistive heater comprises a second coil and wherein the first coil and the second coil are each wrapped around the wick. ### Claim 3 (depends on 2) The electronic vapor provision device of claim 2, wherein the first coil comprises nichrome and the second coil comprises titanium. ### Claim 4 (depends on 2) The electronic vapor provisional device of claim 2, wherein the second coil has a second radius that is larger than a first radius of the first coil. ### Claim 5 (depends on 2) The electronic vapor provisional device of claim 2, wherein the second coil has a second length that is less than a first length of the first coil. ### Claim 6 (depends on 1) The electronic vapor provision device of claim 1, wherein the first electrical resistive heater comprises a first coil and the second electrical resistive heater comprises one or more strip heaters. ### Claim 7 (depends on 1) The electronic vapor provision device of claim 1, wherein the second thermal coefficient of resistance is at least four times larger than the first thermal coefficient of resistance. ### Claim 8 (depends on 7) The electronic vapor provision device of claim 7, wherein the second thermal coefficient of resistance is at least eight times larger than the first thermal coefficient of resistance. ### Claim 9 (depends on 1) The electronic vapor provision device of claim 1, wherein the control system comprises a current sensor to monitor a current level of the second electrical resistive heater. ### Claim 10 (depends on 1) The electronic vapor provision device of claim 1, wherein the first electrical resistive heater and the second electrical resistive heater are arranged to aerosolize the same e-liquid from the reservoir. ### Claim 11 A cartridge for use in an electronic vapor provision device, the cartridge comprising: a first electrical resistive heater having a first thermal coefficient of resistance; a second electrical resistive heater having a second thermal coefficient of resistance that is at least two times larger than the first thermal coefficient of resistance; a wick for transporting e-liquid from a reservoir to the first electrical resistive heater and the second electrical resistive heater; and a connection for electrically connecting the cartridge to a control system configured to monitor for a change in resistance of the second electrical resistive heater, wherein the first electrical resistive heater and the second electrical resistive heater are each mounted around the wick. ### Claim 12 (depends on 11) The cartridge of claim 11, wherein the first electrical resistive heater comprises a first coil and the second electrical resistive heater comprises a second coil and wherein the first coil and the second coil are each wrapped around the wick. ### Claim 13 (depends on 12) The cartridge of claim 12, wherein the first coil comprises nichrome and the second coil comprises titanium. ### Claim 14 (depends on 12) The cartridge of claim 12, wherein the second coil has a second radius that is larger than a first radius of the first coil. ### Claim 15 A method of operating an electronic vapor provision device, comprising: transporting e-liquid from a reservoir to a wick; vaporizing a precursor material using the first electrical resistive heater mounted on the wick to generate vapor in an airflow for inhalation by a user; vaporizing the precursor material using the second electrical resistive heater mounted on the wick to generate vapor in an airflow for inhalation by a user, wherein the second electrical resistive heater has a second thermal coefficient of resistance that is at least two times larger than a first thermal coefficient of resistance of the first electrical resistive heater; and monitoring, by a control system, for a change in resistance of the second electrical resistive heater.