Induction Cookware

• US 20090065500A1
• Filed: 09/05/2008
• Published: 03/12/2009
• Est. Priority Date: 09/07/2007
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Froeschle, Thomas A., England, Raymond O., Beverly, David W.
• Granted Patent: US 8,796,598 B2
• Time in Patent Office: Days
• US Class Current: 219/621
• CPC Class Codes: A47J 27/002 Construction of cooking-vessels; Methods or processes of manufacturing specially adapted for cooking-vessels
• CPC Class Codes: A47J 36/02 Selection of specific materials, e.g. heavy bottoms with copper inlay or with insulating inlay
• CPC Class Codes: A47J 36/36 Shields or jackets for cooking utensils minimising the radiation of heat, fastened or movably mounted
• CPC Class Codes: A47J 39/00 Heat-insulated warming chambers; Cupboards with heating arrangements for warming kitchen utensils
• CPC Class Codes: A47J 41/0077 made of two vessels inserted in each other
• CPC Class Codes: A47J 41/02 Vacuum-jacket vessels, e.g. vacuum bottles
• CPC Class Codes: H01F 41/00 Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
• CPC Class Codes: H05B 6/12 Cooking devices
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

An induction cooking utensil is constructed such that it cooks food within its chamber while maintaining a relatively cool outer surface (e.g., preferably an outer surface that is cool enough to pick up with one'"'"'s bare hands). The cooking utensil includes an inner wall that is made at least in part of an electrically conductive material and an outer wall that is made at least in part of the electrically non-conductive material. A reflective layer, a vacuum-sealed thermal insulator and/or a gas more resistant to conducting heat than air is disposed between the inner and outer walls to resist the transfer of heat from the inner wall to the outer wall.

Claims

1. A cooking utensil for use with an induction cooktop having an induction coil, the cooking utensil comprising:

an inner wall comprising an electrically conductive target layer in which heat is generated by the induction coil;

an outer wall comprising an electrically non-conductive layer that cooperates with the inner wall to form a sealed gap between the inner wall and the outer wall; and

argon gas filling the sealed gap.

2. The cooking utensil of claim 1, wherein the outer wall further comprises a reflective layer disposed on a surface of the outer wall that defines a portion of the gap and faces the inner wall.

3. The cooking utensil of claim 2, wherein the reflective layer is non-contiguous to interrupt a flow of a current induced in the reflective layer by the induction coil.

4. The cooking utensil of claim 1, wherein the outer wall further comprises an impermeable material to aid in reducing the permeation of an atmospheric gas through the outer wall and into the gap.

5. The cooking utensil of claim 1, wherein the outer wall provides a passage opening into the gap to enable the gap to be filled with the argon gas.

6. The cooking utensil of claim 1, wherein the inner wall further comprises a heat spreader layer and a cooking layer.

7. The cooking utensil of claim 6, wherein:

the inner wall has a pan-like shape having a substantially flat bottom portion, having an inner surface defining a cooking chamber, and having an outer surface that defines a portion of the gap and faces the outer wall;

the cooking layer provides substantially all of the inner surface;

the target layer provides the outer surface within the bottom portion; and

the heat spreader layer conducts heat generated in the target layer to at least the cooking layer within the bottom portion.

8. The cooking utensil of claim 1, wherein the argon gas is maintained at a pressure less than atmospheric pressure at sea level.

9. The cooking utensil of claim 1, further comprising a vacuum-sealed thermal insulator disposed within the gap and away from contact with the inner wall, wherein the vacuum-sealed thermal insulator is comprised of a thermally resistant material and a pair of sheets enclosing the thermally resistant material in a vacuum.

10. The cooking utensil of claim 9, further comprising a piece of getter material disposed within the gap to remove a gas other than the argon gas.

11. A cooking utensil for use with an induction cooktop having an induction coil, the cooking utensil comprising:

an inner wall comprising an electrically conductive target layer in which heat is generated by the induction coil;

an outer wall comprising an electrically non-conductive layer that cooperates with the inner wall to form a sealed gap between the inner wall and the outer wall; and

a vacuum-sealed thermal insulator disposed within the gap and away from contact with the inner wall, wherein the vacuum-sealed thermal insulator is comprised of a thermally resistant material and a pair of sheets enclosing the thermally resistant material in a vacuum.

12. The cooking utensil of claim 11, wherein the outer wall further comprises an impermeable material to aid in reducing the permeation of an atmospheric gas through the outer wall and into the gap.

13. The cooking utensil of claim 11, wherein the inner wall further comprises a heat spreader layer and a cooking layer.

14. The cooking utensil of claim 13, wherein the inner wall has a pan-like shape having a substantially flat bottom portion, having an inner surface defining a cooking chamber, and having an outer surface that defines a portion of the gap and faces the outer wall, wherein:

the cooking layer provides substantially all of the inner surface;

the target layer provides the outer surface within the bottom portion; and

the heat spreader layer conducts heat generated in the target layer to at least the cooking layer within the bottom portion.

15. The cooking utensil of claim 11, wherein the thermally resistant material of the vacuum-sealed thermal insulator comprises an aerogel.

16. The cooking utensil of claim 11, wherein at least one sheet of the pair of sheets of the vacuum-sealed thermal insulator comprises silicon-dioxide.

17. The cooking utensil of claim 11, wherein at least one sheet of the pair of sheets of the vacuum-sealed thermal insulator comprises a metalized polymer.

18. The cooking utensil of claim 11, wherein the vacuum-sealed thermal insulator is affixed to an inner surface of the outer wall that defines a portion of the gap.

19. The cooking utensil of claim 11, wherein:

the inner wall and the outer wall cooperate to provide the cooking utensil a pan-like shape having a bottom portion and a side wall portion, and wherein the inner wall is nested within the outer wall; and

the vacuum-sealed thermal insulator is disposed within a portion of the gap within the bottom portion.

20. The cooking utensil of claim 19, further comprising a reflective layer disposed on a surface of the outer wall that defines a portion of the gap within the side wall portion.

21. The cooking utensil of claim 19, further comprising a thermal mat disposed within a portion of the gap within the side wall portion, wherein the thermal mat comprises a fibrous material and an aerogel, and wherein the thermal mat is affixed to a surface of the outer wall that defines a portion of the gap.

22. The cooking utensil of claim 19, wherein the target layer is disposed within a portion of the gap within the bottom portion, and wherein the vacuum-sealed thermal insulator extends further across the bottom portion than does the target layer.

23. The cooking utensil of claim 11, further comprising argon gas filling the gap.

24. A method of making a cooking utensil, the method comprising joining an outer wall comprising an electrically non-conductive layer to an inner wall comprising an electrically conductive target layer in which heat is generated by an induction coil of an induction cooktop to define a gap between the inner wall and the outer wall to enclose argon gas within the gap.

25. The method of claim 24, wherein the joining of the outer wall and the inner wall is performed in an argon gas environment.

26. The method of claim 24, further comprising:

forming a passage through a portion of the outer wall;

filling the gap with argon gas through the passage; and

sealing the passage.

27. The method of claim 24, further comprising:

disposing a piece of getter material within the gap; and

activating the getter material subsequent to joining the outer wall to the inner wall to remove a gas other than argon from within the gap.

28. The method of claim 27, further comprising selecting a quantity and a type of the getter material to remove a selected quantity and composition of gases from within the gap to achieve a gaseous environment within the gap comprised of argon gas at a pressure less than atmospheric pressure at sea level.