# US 2019/0170363 A1 · Glass-Ceramic Cooking Apparatus and A Method relating to Temperature Limiting Control for Preventing Cooking Oil Ignition > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170363 A1 - Document ID: US20190170363A1 - Status: Published application - Kind: A1 - Application number: 16/003,148 - Filed: 2018-06-08 - Published: 2019-06-06 - Earliest claimed: 2017-12-05 - Assignees: Zhejiang Jiu Kang Electric Appliances Co., Ltd. - Applicants: Zhejiang Jiu Kang Electric Appliances Co., Ltd. - Inventors: Chunlei SHEN; Yun BAI - Web page: https://patentgrep.com/patent/US20190170363A1 ## CPC - F24C 7/088: {on stoves} - A62C 3/006: {for kitchens or stoves} - F24C 7/083: {on tops, hot plates} - F24C 15/102: {electrically heated} - F24C 15/105: {Constructive details concerning the regulation of the temperature} - F24C 15/106: {electric circuits} - H05B 1/0266: {Cooktops} - H05B 3/746: {Protection, e.g. overheat cutoff, hot plate indicator} - H05B 2213/04: Heating plates with overheat protection means - F24C: DOMESTIC STOVES OR RANGES (exclusively for solid fuels F24B); DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION - A62C: FIRE-FIGHTING (fire-extinguishing compositions, use of chemical substances in extinguishing fires A62D1/00; spraying, applying liquids or other fluent materials to surfaces in general B05; alarm arrangements G08B, e.g. fire alarms actuated by smoke or gases G08B17/10) - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A glass-ceramic cooking apparatus and a method relating to temperature limiting control of the glass heating area for preventing cooking oil ignition is disclosed. The apparatus comprises at least one glass surface, at least one heat source under the glass to create a heating area on the glass, one temperature sensor and one control unit for each heat source, wherein the sensor measures the temperature on the underside the glass heating area, and the control unit is electrically connected with the heat source, compares the measured glass temperature with predetermined upper and lower temperature limits that are based on a corresponding relationship between the heating area temperature and the cooking oil temperature within the cooking vessel, and then reduces or increases the output power of the heating source, so that the maximum temperature of the cooking oil in the cooking vessel can be limited in a range that is below the cooking oil ignition point while a minimum temperature can still be maintained for a desired cooking performance. ## Claims ### Claim 1 A glass-ceramic cooking apparatus comprising at least: one glass surface for supporting and heating cooking vessels; at least one heating element mounted below the glass; a temperature sensor for each heating element placed on the underside of the glass for measuring the temperature of the glass heating area; and a control unit for each heating element electrically connected with the heating element for adjusting the output power of the heating element; the control unit compares the temperature sensor's measurement with predetermined upper and lower temperature limits derived from an established relationship between the measured glass temperature and the cooking oil temperature during cooking, whereby when the measured temperature reaches the upper temperature limit, the control unit reduces output power of the heating element, and when the measured temperature reaches the lower temperature limit, the control unit increases output power of the heating element, such that the cooking oil temperature within the cooking vessel is limited in a controlled cycle and kept below the cooking oil ignition point while still maintains the minimum temperature for a desired cooking performance. ### Claim 2 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, wherein the upper temperature limit is determined based on the cooking oil ignition point and the established relationship between the glass temperature measured by the temperature sensor and the cooking oil temperature within the cooking vessel, which takes into account the temperature sensor type, the positioning and mounting of the temperature sensor, the heating element style and output power, and the cooking vessel type, whereby the upper temperature limit is reached when the maximum cooking oil temperature in the cooking vessel approaches but never reaches the cooking oil ignition point. ### Claim 3 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, wherein the lower temperature limit is determined based on the minimum temperature for a desired cooking performance and the established relationship between the glass temperature measured by the temperature sensor and the cooking oil temperature within the cooking vessel, whereby the lower temperature limit is reached when the cooking oil temperature in the cooking vessel reaches the minimum temperature required for the desired cooking performance. ### Claim 4 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, further comprising a temperature limiter, which includes a control unit connected with the heating element and a temperature sensor enclosed within a multi-layer sleeve with an inner insulation layer and an outer insulation layer; the sleeve is adapted to insulate the temperature limiter probe to reduce heat transferring from the heating element, whereby the measured temperature reflects the temperature of the glass heating area; and wherein the temperature limiter's control unit compares the measured temperature with predetermined temperature limits, and then controls the output power of the heating element. ### Claim 5 (depends on 4) The glass-ceramic cooking apparatus according to claim 4, wherein the multi-layer sleeve is made of ceramic, glass or steel. ### Claim 6 (depends on 4) The glass-ceramic cooking apparatus according to claim 4, wherein the multi-layer sleeve further comprises a metallic reflective coating between the inner layer and outer layer. ### Claim 7 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, wherein the temperature sensor is placed on the underside of the glass heating area for measuring the temperature of the glass, and sends the temperature measurement to the control circuit and/or the control unit; the control unit integrated in the control circuit is electrically connected with the heating element. ### Claim 8 (depends on 7) The glass-ceramic cooking apparatus according to claim 7, wherein the temperature sensor comprises a temperature probe, heat insulation material and a ceramic case; the temperature probe contacting in direct with the glass is surrounded by the heat insulating material, wherein the heat insulation material is compressed between the glass and the ceramic case for insulating the heat transferring from the heating element to the probe and the glass within the insulating material, whereby the glass within the insulation material has the heat source mainly from the cookware placed on the glass heating area. ### Claim 9 (depends on 7) The glass-ceramic cooking apparatus according to claim 7, wherein the temperature sensor is glued on the underside of the glass, or—the temperature sensor is pressed against the underside of the glass by an elastic device. ### Claim 10 (depends on 7) The glass-ceramic cooking apparatus according to claim 7, wherein the heating wire in the heating element is placed with a non-heating zone right below the sensor to further reduce the heat transferring from the heating wire to the sensor. ### Claim 11 (depends on 7) The glass-ceramic cooking apparatus according to claim 7, wherein the temperature sensor can be a single device or multiple duplicated devices distributed on the underside of the glass. ### Claim 12 (depends on 7) The glass-ceramic cooking apparatus according to claim 7, wherein the temperature sensor is a fiber optic temperature sensor, a resistive temperature sensor, a high temperature thermistor, a polymer-derived ceramics (PDC) sensor, or a thermocouple. ### Claim 13 (depends on 7) The glass-ceramic cooking apparatus according to claim 7, wherein the temperature sensor is applied with an infrared coating on the sensor surface contacting with the glass for improving the measurement performance. ### Claim 14 (depends on 7) The glass-ceramic cooking apparatus according to claim 7, wherein the control unit is a relay, a set of relays or a silicon-controlled rectifier (SCR). ### Claim 15 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, wherein the temperature sensor and control unit are integrated in one temperature controller, and the temperature controller is placed on the underside of the glass heating area. ### Claim 16 (depends on 15) The glass-ceramic cooking apparatus according to claim 15, wherein the temperature controller comprising a sensor, a control unit, insulation material and a ceramic case; the controller's sensor contacts in direct with the underside of the glass and is connected with the control unit; the controller's control unit is connected with the heating element; the sensor and the control unit are surrounded in the heat insulating material, wherein the heat insulation material is compressed between the glass and the ceramic case for insulating the heat transferring from the heating element to the sensor and the glass within the insulating material, whereby the glass within the insulation material has the heat source mainly from the cookware placed on the glass heating area. ### Claim 17 (depends on 15) The glass-ceramic cooking apparatus according to claim 15, wherein the temperature controller is glued on the underside of the glass, or the temperature controller is pressed against the underside of the glass by an elastic device. ### Claim 18 (depends on 15) The glass-ceramic cooking apparatus according to claim 15, wherein the heating wire in the heating element is placed with a non-heating zone right below the temperature controller to further reduce the heat transferring from the heating wire to the controller. ### Claim 19 (depends on 15) The glass-ceramic cooking apparatus according to claim 15, wherein the temperature controller is a thermostat. ### Claim 20 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, further comprising a “hot surface” indicator connected with a temperature sensor measuring the temperature of the glass heating area and configured to warn the user “the heating surface is hot” when the heating area temperature reaches a predetermined temperature. ### Claim 21 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, further comprising an automatic shutdown switch whereby all heating elements are shut off after the power selector of any heating element is not changed by the user over a predetermined period. ### Claim 22 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, wherein the control unit is configured to limit the temperature cycle time between 10-60 seconds by using a narrow upper and lower temperature limit range to maintain a higher average cooking temperature for a desired cooking performance while still prevent cooking oil ignition. ### Claim 23 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, wherein the heating element has a rated output power between 500 W and 3500 W. ### Claim 24 (depends on 1) The glass-ceramic cooking apparatus according to claim 1, wherein the heating element is a radiant heating element, an infrared halogen lamp or an induction heating element. ### Claim 25 A method of applying temperature limiting control of the heating area on a cooking apparatus to prevent cooking oil ignition during cooking while maintain a desired cooking performance; the method comprises a. testing to establish the relationship between the temperature of the heating area and the cooking oil temperature within the cooking vessel; b. based on said relationship, setting up an upper temperature limit for controlling the heating source output power to limit the maximum cooking oil temperature below the oil ignition point, and setting up a lower temperature limit to maintain the cooking oil temperature above the minimum temperature required for a desired cooking performance; c. creating a heat insulated spot on the heating area; blocking the heat transferring from the heating source to the heat insulated spot; making the heat transferring from the cooking vessel placed on the heating area the main heat source to the heat insulated spot; d. measuring the temperature of the heat insulated spot; e. comparing the measured temperature with the upper and lower temperature limits; reducing output power of the heating source as the measured temperature reaches the upper temperature limit; or increasing output power of the heating source as the measured temperature reaches the lower temperature limit.