Induction Cooking

• US 20120132646A1
• Filed: 11/30/2011
• Published: 05/31/2012
• Est. Priority Date: 11/30/2010
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: England, Raymond O., Beverly, David W., Mathieu, Randall
• Granted Patent: US 8,754,351 B2
• Time in Patent Office: Days
• US Class Current: 219/622
• CPC Class Codes: H05B 2213/07 Heating plates with temperature control means
• CPC Class Codes: H05B 6/062 for cooking plates or the like

Abstract

An induction cooking system with an induction heating system, a cooktop, and cool touch cookware that has a target layer that is heated by induction. An absolute cookware temperature is directly sensed at one or more locations of the cookware. A relative cookware temperature can be determined based on the value of an electrical variable of a circuit that includes the target layer. The cookware can include a layer of thermal insulation directly below and spaced from the target layer by a gap. The insulation and gap act as the major heat insulating elements to keep the outer surface of the cookware cool. The cooktop can be cooled by placing a cooling chamber just below the cooktop and drawing air through the cooling chamber. The induction coil can be located in the cooling chamber.

Claims

1. An induction cooking system comprising:

(i) an induction cooking appliance comprising;

a cooktop having an upper and lower surface;

power electronics located below the lower surface of the cooktop;

an electrical coil positioned below the lower surface of the cooktop, wherein the electrical coil is operatively connected to the power electronics and configured to produce an electromagnetic field when the coil is energized by the power electronics; and

(ii) custom cookware configured to be placed on the cooktop above the electrical coil, the custom cookware comprising;

an inner wall comprising a target layer formed of an electrically conductive material, wherein an electrical current is induced in the target layer by the electromagnetic field generated by the coil; and

an outer wall formed at least partially of a first layer of thermal insulation material, wherein the first layer of thermal insulation material is spaced from the target layer such that there is a gap between the thermal insulation and the target layer, wherein the outer wall is configured to rest on the upper surface of the cooktop above the electrical coil during cooking.

2. The induction cooking system of claim 1 wherein the electrical coil is positioned immediately below and spaced from the lower surface of the cooktop.

3. The induction cooking system of claim 1 wherein the pressure in the gap is less than 14.7 pounds per square inch.

4. The induction cooking system of claim 1 wherein the gap comprises a gas that is less heat conductive than air.

5. The induction cooking system of claim 1 wherein the custom cookware further comprises:

a seal between the inner and outer walls;

a space between the inner and outer walls;

wherein the target layer is in the space between the inner and outer walls, physically coupled to the inner wall and spaced from the outer wall;

a temperature sensor operatively coupled to the target layer; and

a transmitter operatively coupled to the temperature sensor.

6. The induction cooking system of claim 5 further comprising a controller operatively coupled to the transmitter.

7. The induction cooking system of claim 6 further comprising one or more cooktop cooling fans, wherein the controller controls the cooling fans based at least in part on the temperature of the target layer.

8. The induction cooking system of claim 6 wherein the controller is arranged to determine whether the seal has failed by determining one or more of:

whether a structure that is in contact with the outer wall of the cookware has exceeded a predetermined temperature;

whether a temperature in the space between the inner and outer walls has exceeded a predetermined temperature;

whether a pressure in the space between the inner and outer walls is outside of a predetermined pressure range;

whether a pressure in the space between the inner and outer walls is not changing in a predetermined manner as the cookware temperature changes; and

whether one or more physical portions of the cookware that are in or exposed to the space between the inner and outer walls have been displaced.

9. The induction cooking system of claim 5 wherein the temperature sensor comprises a direct contact temperature sensor physically coupled to the target.

10. The induction cooking system of claim 5 wherein the temperature sensor comprises a non-contact temperature sensor.

11. The induction cooking system of claim 5 wherein the cookware further comprises a power coil tuned to couple to an electromagnetic field produced by the electrical coil to generate electrical power sufficient to operate the transmitter.

12. The induction cooking system of claim 5 wherein the transmitter comprises an RF enabled microprocessor.

13. The induction cooking system of claim 5 wherein the cookware outer wall is made at least in part of electrically non-conductive material, and wherein the transmitter is spaced from the first layer of thermal insulation material.

14. The induction cooking system of claim 5 wherein the transmitter comprises a second temperature sensor.

15. The induction cooking system of claim 5 further comprising a gas or vacuum in the space between the inner and outer walls, and wherein the thermal resistance of the space between the inner and outer walls and the first layer of thermal insulation material in combination is at least 10 degrees C. per watt.

16. An induction cooking system comprising:

(i) an induction cooking appliance comprising;

power electronics;

a plurality of electrical coils operatively connected to the power electronics, the coils when energized by the power electronics producing an electromagnetic field;

a cooktop located above the electrical coils; and

(ii) custom cookware configured to be placed on the cooktop above an electrical coil, the custom cookware comprising;

an inner wall;

an outer wall;

a seal between the inner and outer walls;

a space between the inner and outer walls;

a target layer in which electrical current is induced by the electromagnetic field, wherein the target is located in the space between the inner and outer walls, physically coupled to the inner wall and spaced from the outer wall;

a layer of thermal insulation located below and spaced from the target layer;

a temperature sensor operatively coupled to the target layer;

a transmitter operatively coupled to the temperature sensor;

a power coil tuned to couple to an electromagnetic field produced by the electrical coils to generate electrical power sufficient to operate the transmitter; and

a gas or vacuum in the space between the inner and outer walls, wherein the thermal resistance of the space between the inner and outer walls and the layer of thermal insulation in combination is at least 10 degrees C. per watt.

17. The induction cooking system of claim 16 wherein the electrical coil is positioned immediately below and spaced from the lower surface of the cooktop.

18. The induction cooking system of claim 16 further comprising a controller operatively coupled to the transmitter and one or more cooktop cooling fans, wherein the controller controls the cooling fans based at least in part on the temperature of the target.