Food warming apparatus

• US 7,328,654 B2
• Filed: 10/31/2003
• Issued: 02/12/2008
• Est. Priority Date: 07/10/2002
• Status: Active Grant

• Current Assignee: Duke Manufacturing Company
• Original Assignee: Duke Manufacturing Company
• Inventors: Shei, Steven M.
• Primary Examiner(s): ALEXANDER, REGINALD
• Application Number:
  US10/698,693
• Publication Number:
  US 20060185527A1
• Time in Patent Office: 1,565 Days
• Field of Search: 994/83, 994/84, 993/74, 993/89, 994/48, 994/68, 994/74, 994/76, 219/394, 219/413, 219/389, 219/399, 219/385, 219/392, 219/386, 219/214, 219/506, 219/486, 219/494
• US Class Current: 99/468
• CPC Class Codes: A47J 39/006 for either storing and preparing or for preparing food on serving trays, e.g. heating, thawing, preserving
• CPC Class Codes: F24C 7/06 Arrangement or mounting of electric heating elements
• CPC Class Codes: F24C 7/087 of electric circuits regulating heat

Abstract

In general, one embodiment of the invention is directed to apparatus for warming pre-cooked sandwich buns and the like to a desired holding temperature and then holding the buns at such holding temperature. The apparatus comprises a cabinet having at least one compartment with a bottom wall, a top wall and opposite side walls. Adjacent the bottom of the compartment is at least one heat source for delivering heat to buns in the compartment. A control mechanism controls the heat source to deliver heat to the buns to warm the buns to the desired holding temperature and then to vary the amount of heat delivered to the buns to hold the buns at the desired holding temperature. A related method is also disclosed.

Claims

1. Food holding apparatus for holding pre-cooked food at a selected holding temperature, said apparatus comprising:

a cabinet having a plurality of holding compartments for holding said pre-cooked food therein;

a heat source in each compartment of said plurality of compartments for delivering heat to the food in the compartment; and

a control mechanism programmed to vary the heat delivered by each heat source to the food in a respective holding compartment through a duration of holding time during which;

said control mechanism operates to activate said heat source such that said duration comprises a first period of time during which the heat source operates at a first duty cycle whereby the food reaches said selected holding temperature,

said control mechanism operates to activate said heat source such that said duration comprises a second period of time after the first period of time during which the heat source operates at a second duty cycle different from said first duty cycle whereby the food is held at said selected holding temperature, and

said control mechanism operates to activate said heat source such that said duration comprises a third period of time after the second period of time at which the heat source operates at a third duty cycle different from said first and second duty cycles whereby the food is maintained at said selected holding temperature.

2. Food holding apparatus as set forth in claim 1 wherein said second duty cycle is less than said first duty cycle and said third duty cycle is greater than said second duty cycle but less than said first duty cycle.

3. Food holding apparatus as set forth in claim 2 wherein said second duty cycle is zero.

4. Food holding apparatus as set forth in claim 2 wherein said heat source is located in a bottom wall of a respective holding compartment of said plurality of compartments.

5. Apparatus as set forth in claim 3 wherein each compartment of said plurality of compartments comprises opposite side walls which are not heated.

6. Apparatus as set forth in claim 5 wherein each compartment of said plurality of compartments comprises a top wall which is not heated.

7. Food holding apparatus as set forth in claim 1 wherein said second duty cycle is greater than said first duty cycle and said third duty cycle is less than said second duty cycle but greater than said first duty cycle.

8. Food holding apparatus as set forth in claim 7 wherein said first duty cycle is zero.

9. Food holding apparatus as set forth in claim 8 wherein said heat source is located adjacent a top wall of a respective holding compartment of said plurality of compartments for emitting radiant heat down on said food.

10. Apparatus as set forth in claim 1 further comprising a vertical partition in the cabinet dividing the cabinet into a plurality of separate side-by-side compartments, and wherein said control mechanism is programmed for controlling operation of the heat sources independent of one another whereby the temperature in each compartment of said plurality of compartments may be independently controlled.

11. Apparatus as set forth in claim 1 wherein said control mechanism comprises an operator display device for counting down a time remaining in said duration of holding time.

12. Apparatus as set forth in claim 1 wherein said control mechanism comprises at least one sensor in each holding compartment of said plurality of compartments for detecting a characteristic indicative of the temperature of the food in the compartment, the control mechanism being responsive to signals from said sensor to vary the amount of heat delivered by a respective heat source.

13. Apparatus as set forth in claim 12 wherein said sensor is a temperature sensor for detecting the temperature of a surface in a respective compartment of said plurality of compartments.

14. Apparatus as set forth in claim 12 wherein said sensor is operable to detect radiant energy emitted by the food in a respective compartment of said plurality of compartments.

15. Apparatus as set forth in claim 1 wherein said control mechanism is programmed to operate each heat source during each of said first, second and third periods of time in successive time-based cycles, each time-based cycle comprising a predetermined on-time interval during which the heat source is activated and a predetermined off-time interval during which said heat source is de-activated, and wherein said control mechanism is programmed to vary the amount of heat by changing the ratio of said predetermined on-time interval to the sum of said predetermined on-time and off-time intervals.

16. Apparatus as set forth in claim 1 wherein said control mechanism varies the amount of heat delivered by said heat source without deactivating the heat source.

17. Apparatus as set forth in claim 1 further comprising a cover secured to one or more walls of at least one of the compartments of said plurality of compartments for covering a pan in said at least one compartment to inhibit the escape of moisture from food in the pan.

18. Apparatus as set forth in claim 17 wherein said cover floats up and down to accommodate pans having different heights placed in said at least one compartment of said plurality of compartments.

19. Apparatus as set forth in claim 1 wherein the compartments of said plurality of compartments are arranged side-by-side.

20. Apparatus as set forth in claim 19 further comprising a plurality of pans for placement in said plurality of compartments, and wherein each compartment of said plurality of compartments is sized for receiving only one of said pans per compartment.

21. Apparatus as set forth in claim 1 further comprising pre-cooked food in each holding compartment of said plurality of holding compartments, said radiant heat source in the holding compartment being spaced above the food a distance less than 30.5 cm for delivering radiant heat to the food.