Induction-based food holding/warming system and method

• US 9,066,374 B2
• Filed: 06/25/2014
• Issued: 06/23/2015
• 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): Ross, Dana
• Assistant Examiner(s): LAFLAME JR, MICHAEL A
• Application Number:
  US14/314,931
• Publication Number:
  US 20140305931A1
• Time in Patent Office: 363 Days
• Field of Search: 219/608, 219/618, 219/621, 219/620, 219/624, 219/630, 219/632, 219/108, 219/200, 219/102, 219/112, 219/162, 336/15, 336/65, 994/51
• US Class Current: 1/1
• 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 method for holding and warming food. The method includes the steps of: using a container formed of 300-series stainless steel, wherein the container is formed by a cold working process; and applying to the container a magnetic field from an induction coil, wherein the magnetic field is sufficient to induce a current in the container to heat the container.

Claims

1. A method for holding and warming food, the method comprising the steps of:

disposing a container consisting of 300-series stainless steel in a receptacle for receiving the container, wherein the container is formed by a cold working process; and

applying to the container a magnetic field from an induction coil, wherein the magnetic field is sufficient to induce a current in the container to heat the container,

wherein the container includes a rim extending around a perimeter thereof, and wherein the rim of the container rests on an edge of the receptacle.

2. The method of claim 1, wherein the induction coil applies a magnetic field produced by 200 to 440 ampere-turns.

3. The method of claim 1, wherein the induction coil applies a magnetic field produced by 300 to 600 ampere-turns.

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

5. The method of claim 1, further comprising monitoring a temperature of the container using a temperature sensor in direct contact with an underside of the container.

6. The method of claim 1, wherein the temperature sensor operates in a closed loop with the container and the induction coil.

21. The method of claim 1, wherein the induction coil applies a magnetic field produced by at least 200 ampere-turns.

22. The method of claim 6, wherein the temperature sensor is biased toward the container.

7. An apparatus for holding and warming food, the apparatus comprising:

a container consisting of 300-series stainless steel formed to contain food, wherein the container is formed by a cold working process;

a receptacle for receiving the container;

an induction coil having a plurality of turns, the induction coil located below the receptacle; and

a circuit electrically connected to the induction coil to supply a first current to the induction coil,

wherein

the induction coil applies a magnetic field produced by at least 200 ampere-turns such that the magnetic field is sufficient to induce a second current in the container to heat the container,

the container includes a rim extending around a perimeter thereof,

the rim of the container rests on an edge of the receptacle.

8. The apparatus of claim 7, wherein the induction coil applies a magnetic field produced by 200 to 440 ampere-turns.

9. The apparatus of claim 7, wherein the induction coil applies a magnetic field produced by 300 to 600 ampere-turns.

10. The apparatus of claim 7, wherein the container has a relative magnetic permeability less than 100.

11. The apparatus of claim 7, further comprising a temperature sensor in direct contact with an underside of the container for monitoring a temperature of the container.

12. The apparatus of claim 11, wherein the temperature sensor operates in a closed loop with the container and the induction coil.

23. The apparatus of claim 12, wherein the temperature sensor is biased toward the container.

13. An apparatus for holding and warming food, the apparatus comprising:

a container consisting of 300-series stainless steel formed to contain food, wherein the container is formed by a cold working process;

a receptacle for receiving the container;

an induction coil having a plurality of turns, the induction coil located below the receptacle; and

a circuit electrically connected to the induction coil to supply a first current to the induction coil; and

a temperature sensor to directly measure a temperature on an underside of the container,

wherein the induction coil applies a magnetic field sufficient to induce a second current in the container to heat the container.

14. The apparatus of claim 13, wherein the container has a relative magnetic permeability less than 100.

15. The apparatus of claim 13, wherein the temperature sensor is in direct contact with an underside of the container.

16. The apparatus of claim 15, wherein the temperature sensor operates in a closed loop with the container and the induction coil.

19. The apparatus of claim 13, wherein the temperature sensor is in direct contact with an underside of the container.

20. The apparatus of claim 19, wherein the temperature sensor operates in a closed loop with the container and the induction coil.

24. The apparatus of claim 13, wherein the container includes a rim extending around a perimeter thereof and wherein the rim of the container rests on an edge of the receptacle.

25. The apparatus of claim 24, wherein the induction coil applies a magnetic field produced by at least 200 ampere-turns.

26. The apparatus of claim 16, wherein the temperature sensor is biased toward the container.

28. The apparatus of claim 20, wherein the temperature sensor is biased toward the container.

17. An apparatus for holding and warming food, the apparatus comprising:

a container consisting of 300-series stainless steel formed to contain food, wherein the container is formed by a cold working process;

a receptacle for receiving the container;

an induction coil having a plurality of turns, the induction coil located below the receptacle;

a circuit electrically connected to the induction coil to supply a first current to the induction coil; and

a temperature sensor to directly measure a temperature of an underside of the container,

wherein

the induction coil applies a magnetic field sufficient to induce a second current in the container to heat the container, and

the container includes a rim extending around a perimeter thereof and the rim of the container rests on an edge of the receptacle.

18. The apparatus of claim 17, wherein the container has a relative magnetic permeability less than 100.

27. The apparatus of claim 17, wherein the induction coil applies a magnetic field produced by at least 200 ampere-turns.