Induction-based food holding/warming system and method

• US 9,848,463 B2
• Filed: 02/24/2017
• Issued: 12/19/2017
• Est. Priority Date: 05/20/2011
• Status: Active Grant

• Current Assignee: Cooktek Induction Systems, LLC (Middleby Corporation)
• Original Assignee: Cooktek Induction Systems, LLC (Middleby Corporation)
• Inventors: Graber, Warren S., Metz, Reinhard, Visher, Robert J.
• Primary Examiner(s): LAFLAME JR, MICHAEL A
• Application Number:
  US15/441,444
• Publication Number:
  US 20170164428A1
• Time in Patent Office: 298 Days
• Field of Search: 219608, 219618, 219621, 219620, 219624, 219630, 219632, 336 15, 336 65
• CPC Class Codes: A47J 36/24 Warming devices
• CPC Class Codes: A47J 36/2483 with electrical heating means
• CPC Class Codes: H05B 2213/07 Heating plates with temperature control means
• CPC Class Codes: H05B 6/062 for cooking plates or the like
• CPC Class Codes: H05B 6/105 using a susceptor
• CPC Class Codes: H05B 6/12 Cooking devices
• CPC Class Codes: H05B 6/1209 induction cooking plates or the like and devices to be used in combination with them
• CPC Class Codes: H05B 6/36 Coil arrangements
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A system for holding and warming food includes a container for holding and warming food. The container consists of 300-series stainless steel. The system further includes an induction heating unit with an induction heating circuit for induction heating the container. The induction heating circuit includes a 120 volt induction coil having 40 or more turns. The induction heating circuit operates at a frequency greater than 30 kilohertz.

Claims

1. A system for holding and warming food, the system comprising:

a container for holding and warming food, the container consisting of 300-series stainless steel; and

an induction heating unit with an induction heating circuit for induction heating the container, the induction heating circuit including a 120 volt induction coil having 40 or more turns, and wherein the induction heating circuit operates at a frequency greater than 30 kilohertz.

2. The system of claim 1, wherein the frequency that the induction heating circuit operates at is 40 kilohertz to 60 kilohertz.

3. The system of claim 1, wherein the induction coil comprises 14 gauge wire.

4. The system of claim 1, wherein the induction coil has an inductance of at least 820 microhenries.

5. The system of claim 1, wherein the induction coil operates at a current of 5 amperes to 11 amperes.

6. The system of claim 1, wherein the container has a relative magnetic permeability less than 100.

7. The system of claim 1, further comprising an electronic device for determining a temperature measurement of the container.

8. The system of claim 7, wherein the temperature measurement is used in a closed loop control to limit and maintain a temperature of the container at a desired value.

9. The system of claim 8, wherein the temperature measurement is used to generate a ramped inverter power profile facilitating lateral heat transfer in the container.

10. The system of claim 7, wherein the electronic device for determining the temperature measurement of the container is mounted beneath the container in a manner to facilitate maintaining contact with the container despite variations in shape or size of the container.

11. A system for holding and warming food, system comprising:

a container for holding and warming food, the container consisting of 300-series stainless steel; and

an induction heating unit with an induction heating circuit for induction heating the container, the induction heating circuit including a 240 volt induction coil having 75 or more turns, and wherein the induction heating circuit operates at a frequency greater than 30 kilohertz.

12. The system of claim 11, wherein the frequency that the induction heating circuit operates at is 40 kilohertz to 60 kilohertz.

13. The system of claim 11, wherein the induction coil comprises 18 gauge wire.

14. The system of claim 11, wherein the induction coil has an inductance of at least 250 microhenries.

15. The system of claim 11, wherein the induction coil operates at a current of 4 amperes to 8 amperes.

16. The system of claim 11, wherein the container has a relative magnetic permeability less than 100.

17. The system of claim 11, further comprising an electronic device for determining a temperature measurement of the container.

18. The system of claim 17, wherein the temperature measurement is used in a closed loop control to limit and maintain a temperature of the container at a desired value.

19. The system of claim 18 wherein the temperature measurement is used to generate a ramped inverter power profile facilitating lateral heat transfer in the container.

20. The system of claim 17, wherein the electronic device for determining the temperature measurement of the container is mounted beneath the container in a manner to facilitate maintaining contact with the container despite variations in shape or size of the container.