Food temperature maintenance apparatus

• US 6,073,547 A
• Filed: 09/13/1999
• Issued: 06/13/2000
• Est. Priority Date: 09/13/1999
• Status: Expired due to Term

• Current Assignee: Afs All-American Millwork and Fabrication LLC
• Original Assignee: Standex International Corporation
• Inventors: Delbridge, Randal L., Westbrooks, John W. Jr.
• Primary Examiner(s): SIMONE, TIMOTHY F
• Application Number:
  US09/395,016
• Time in Patent Office: 274 Days
• Field of Search: 99/330-334, 99/339, 99/340, 99/357, 99/467-470, 99/473-476, 99/483, 99/484, 99/516, 99/517, 62/237, 62/331, 165/48.1, 165/61, 165/206, 165/63, 165/64, 165/918, 165/919, 219/400, 219/387, 312/236, 312/410
• US Class Current: 99/468
• CPC Class Codes: A47J 39/003 with forced air circulation
• 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: F25D 17/06 by forced circulation
• CPC Class Codes: F25D 23/12 Arrangements of compartments additional to cooling compartments; Combinations of refrigerators with other equipment, e.g. stove
• CPC Class Codes: F25D 2400/38 Refrigerating devices characterised by wheels
• CPC Class Codes: Y10S 165/919 Wheeled

Abstract

A food temperature maintenance cart transports meals of hot and cold food items prepared at a meal assembly area to a meal serving area where the meals are to be served, while keeping hot foods hot and cold foods cold for extended periods of time. The cart includes a cabinet having tray storage compartments for storing meal serving trays containing refrigerated and heated food items. Thermal barriers subdivide each of the tray storage compartments into a refrigerated compartment for maintaining refrigerated foods in a refrigerated state and a heated compartment for maintaining heated foods in a heated state. A refrigerated air delivery compartment separates adjacent refrigerated compartments and produces laminar flows of refrigerated air across refrigerated food items contained on the trays. A refrigeration blower pulls return air from the lower portion of the refrigerated compartments, up through a refrigeration return plenum containing a refrigeration coil which re-cools the air, and then forces the refrigerated air downwardly through refrigerated air supply plenums and out into the refrigerated compartments in laminar flow across the trays. Each of the heated compartments are heated by a vertically oriented, elongate resistance heating element positioned within a heated air supply plenum. A heater blower pulls return air from the upper portion of the heated compartment and forces the return air downwardly across the elongate heating element which re-heats the air. The heated air is then forced out of the heated air supply plenum into the heated compartment in laminar flow across the trays.

Claims

1. A food temperature maintenance apparatus for maintaining refrigerated food items placed on meal serving trays in a refrigerated state and for maintaining heated food items placed on the meal serving trays in a heated state, the apparatus comprising:

a cabinet having a front, a back, a top, and a bottom, said cabinet including;

a first tray storage compartment for storing meal serving trays containing refrigerated and heated food items;

a second tray storage compartment for storing meal serving trays containing refrigerated and heated food items, said second tray storage compartment separated from the first tray storage compartment by a refrigerated air delivery compartment;

a first thermal barrier for thermally isolating refrigerated and heated food items on meal serving trays in the first tray storage compartment, said first thermal barrier dividing the first tray storage compartment into a first refrigerated compartment adjacent the refrigerated air delivery compartment for maintaining refrigerated food items on the meal serving trays in a refrigerated state and a first heated compartment for maintaining heated food items on the meal serving trays in a heated state;

a second thermal barrier for thermally isolating refrigerated and heated food items on meal serving trays in the second tray storage compartment, said second thermal barrier dividing the second tray storage compartment into a second refrigerated compartment adjacent the refrigerated air delivery compartment for maintaining refrigerated food items on the meal serving trays in a refrigerated state and a second heated compartment for maintaining heated food items on the meal serving trays in a heated state;

a first door adjacent the front of the cabinet for accessing the first tray storage compartment; and

a second door adjacent the front of the cabinet for accessing the second tray storage compartment;

a refrigerator for providing refrigerated air within the refrigerated air delivery compartment;

said refrigerated air delivery compartment including;

a first refrigeration supply plenum adjacent the first refrigerated compartment and including a plurality of through openings;

a second refrigeration supply plenum adjacent the second refrigerated compartment and including a plurality of through openings;

a refrigeration return plenum having an inlet adjacent the bottom of the cabinet for receiving air from the first and second refrigerated compartments;

a refrigeration coil forming a part of said refrigerator and positioned in said refrigeration return plenum; and

a refrigerator blower for producing and circulating refrigerated air through the first and second refrigerated compartments by causing air within the first and second refrigerated compartments to be passed across the refrigeration coil and provided to the first and second refrigeration supply plenums;

wherein refrigerated air within the first refrigeration supply plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across refrigerated food items on meal serving trays in the first refrigerated compartment, downwardly along a forward air return area between the front of the trays and the first door and a rearward air return area between the back of the trays and the back of the cabinet, and to the refrigeration return plenum inlet where the refrigerated air is cycled back across the refrigeration coil by the blower;

wherein refrigerated air within the second refrigeration supply plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across refrigerated food items on meal serving trays in the second refrigerated compartment, downwardly along a forward air return area between the front of the trays and the second door and a rearward air return area between the back of the trays and the back of the cabinet, and to the refrigeration return plenum inlet where the refrigerated air is cycled back across the refrigeration coil by the blower; and

means for heating said first and second heated compartments.

2. The apparatus of claim 1 wherein said means for heating includes:

a first heater for providing heated air to the first heated compartment, said first heater including;

a first heated air plenum having a plurality of through openings for supplying heated air to the first heated compartment;

a first elongate heating element positioned in said first heated air plenum for generating heat;

a first inlet adjacent the top of the cabinet in communication with said first heated air plenum for receiving air from the first heated compartment; and

a first heater blower for forcing air received through the first inlet across the first elongate heating element to produce heated air;

wherein heated air within the first heated air plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across heated food items on meal serving trays in the first heated compartment, upwardly along a forward air return area between the front of the trays and the first door, and to the first heated air plenum inlet where the heated air is cycled back across the first elongate heating element by the first heater blower; and

a second heater for providing heated air to the second heated compartment, said second heater including;

a second heated air plenum having a plurality of through openings for supplying heated air to the second heated compartment;

a second elongate heating element positioned in said second heated air plenum for generating heat;

a second inlet adjacent the top of the cabinet in communication with said second heated air plenum for receiving air from the second heated compartment; and

a second heater blower for forcing air received through the second inlet across the second elongate heating element to produce heated air;

wherein heated air within the second heated air plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across heated food items on meal serving trays in the second heated compartment, upwardly along a forward air return area between the front of the trays and the second door, and to the second heated air plenum inlet where the heated air is cycled back across the second elongate heating element by the second heater blower.

3. The apparatus of claim 2 wherein each of said first and second elongate heating elements includes a vertically oriented electrical resistance heating element having a length at least as great as 50% of the height of the cabinet.

4. The apparatus of claim 1 wherein each of said first and second thermal barriers includes a plurality of thermal dividers vertically arranged within said cabinet to thermally isolate a heated compartment from a refrigerated compartment, wherein each of said dividers is filled with an insulating material.

5. The system of claim 4 wherein each of said food serving trays includes:

a refrigerated food section positioned within a refrigerated compartment;

a heated food section positioned within a heated compartment; and

a tray divider section separating the refrigerated food and heated food sections;

wherein each of said thermal dividers is separated from another thermal divider by a divider gap;

said tray divider section of each meal serving tray being slidably positioned at a divider gap.

6. A food temperature maintenance apparatus for maintaining refrigerated food items placed on meal serving trays in a refrigerated state and for maintaining heated food items placed on the meal serving trays in a heated state, the apparatus comprising:

a cabinet having a front, a back, a top, and a bottom, said cabinet including;

a first tray storage compartment for storing meal serving trays containing refrigerated and heated food items;

a second tray storage compartment for storing meal serving trays containing refrigerated and heated food items;

a first thermal barrier for thermally isolating refrigerated and heated food items on to meal serving trays in the first tray storage compartment, said first thermal barrier dividing the first tray storage compartment into a first refrigerated compartment for maintaining refrigerated food items on the meal serving trays in a refrigerated state and a first heated compartment for maintaining heated food items on the meal serving trays in a heated state;

a second thermal barrier for thermally isolating refrigerated and heated food items on meal serving trays in the second tray storage compartment, said second thermal barrier dividing the second tray storage compartment into a second refrigerated compartment for maintaining refrigerated food items on the meal serving trays in a refrigerated state and a second heated compartment for maintaining heated food items on the meal serving trays in a heated state;

a first door adjacent the front of the cabinet for accessing the first tray storage compartment; and

a second door adjacent the front of the cabinet for accessing the second tray storage compartment;

a first heater for providing heated air to the first heated compartment, said first heater including;

a first heated air plenum having a plurality of through openings for supplying heated air to the first heated compartment;

a first elongate heating element positioned in said first heated air plenum for generating heat;

a first inlet adjacent the top of the cabinet in communication with said first heated air plenum for receiving air from the first heated compartment; and

a first heater blower for forcing air received through the first inlet across the first elongate heating element to produce heated air;

wherein heated air within the first heated air plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across heated food items on meal serving trays in the first heated compartment, upwardly along a forward air return area between the front of the trays and the first door, and to the first heated air plenum inlet where the heated air is cycled back across the first elongate heating element by the first heater blower; and

a second heater for providing heated air to the second heated compartment, said second heater including;

a second heated air plenum having a plurality of through openings for supplying heated air to the second heated compartment;

a second elongate heating element positioned in said second heated air plenum for generating heat;

a second inlet adjacent the top of the cabinet in communication with said second heated air plenum for receiving air from the second heated compartment; and

a second heater blower for forcing air received through the second inlet across the second elongate heating element to produce heated air;

wherein heated air within the second heated air plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across heated food items on meal serving trays in the second heated compartment, upwardly along a forward air return area between the front of the trays and the second door, and to the second heated air plenum inlet where the heated air is cycled back across the second elongate heating element by the second heater blower; and

means for providing refrigerated air the first and second refrigerated compartments.

7. The apparatus of claim 6 wherein each of said first and second elongate heating elements includes a vertically oriented electrical resistance heating element having a length at least as great as 50% of the height of the cabinet.

8. The apparatus of claim 6 wherein said means for providing refrigerated air includes:

a refrigerated air delivery compartment separating the first and second refrigerated compartments said refrigerated air delivery compartment including;

a first refrigeration supply plenum adjacent the first refrigerated compartment and including a plurality of through openings;

a second refrigeration supply plenum adjacent the second refrigerated compartment and including a plurality of through openings;

a refrigeration return plenum having an inlet adjacent the bottom of the cabinet for receiving air from the first and second refrigerated compartments;

a refrigeration coil forming a part of said refrigerator and positioned in said refrigeration return plenum; and

a refrigerator blower for producing and circulating refrigerated air through the first and second refrigerated compartments by causing air within the first and second refrigerated compartments to be passed across the refrigeration coil and provided to the first and second refrigeration supply plenums;

wherein refrigerated air within the first refrigeration supply plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across refrigerated food items on meal serving trays in the first refrigerated compartment, downwardly along a forward air return area between the front of the trays and the first door and a rearward air return area between the back of the trays and the back of the cabinet, and to the refrigeration return plenum inlet where the refrigerated air is cycled back across the refrigeration coil by the blower; and

wherein refrigerated air within the second refrigeration supply plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across refrigerated food items on meal serving trays in the second refrigerated compartment, downwardly along a forward air return area between the front of the trays and the second door and a rearward air return area between the back of the trays and the back of the cabinet, and to the refrigeration return plenum inlet where the refrigerated air is cycled back across the refrigeration coil by the blower.

9. The apparatus of claim 6 wherein each of said first and second thermal barriers includes a plurality of thermal dividers vertically arranged within said cabinet to thermally isolate a heated compartment from a refrigerated compartment, wherein each of said dividers is filled with an insulating material.

10. The system of claim 6 wherein each of said food serving trays includes:

a refrigerated food section positioned within a refrigerated compartment;

a heated food section positioned within a heated compartment; and

a tray divider section separating the refrigerated food and heated food sections;

wherein each of said thermal dividers is separated from another thermal divider by a divider gap;

said tray divider section of each meal serving tray being slidably positioned at a divider gap.

11. An apparatus for transporting prepared meals of refrigerated and heated food items to a meal serving area and for maintaining the refrigerated and heated food items in their refrigerated and heated states for extended periods of time, the apparatus comprising:

a food temperature maintenance cart having;

a cabinet having a front, a back, a top, and a bottom, said cabinet including;

a first tray storage compartment for storing meal serving trays containing refrigerated and heated food items;

a second tray storage compartment for storing meal serving trays containing refrigerated and heated food items;

a first thermal barrier for thermally isolating refrigerated and heated food items on meal serving trays in the first tray storage compartment, said first thermal barrier dividing the first tray storage compartment into a first refrigerated compartment for maintaining refrigerated food items on the meal serving trays in a refrigerated state and a first heated compartment for maintaining heated food items on the meal serving trays in a heated state;

a second thermal barrier for thermally isolating refrigerated and heated food items on meal serving trays in the second tray storage compartment, said second thermal barrier dividing the second tray storage compartment into a second refrigerated compartment for maintaining refrigerated food items on the meal serving trays in a refrigerated state and a second heated compartment for maintaining heated food items on the meal serving trays in a heated state;

a first door adjacent the front of the cabinet for accessing the first tray storage compartment; and

a second door adjacent the front of the cabinet for accessing the second tray storage compartment;

a first heater for providing heated air to the first heated compartment, said first heater including;

a first heated air plenum having a plurality of through openings for supplying heated air to the first heated compartment;

a first elongate heating element positioned in said first heated air plenum for generating heat;

a first inlet adjacent the top of the cabinet in communication with said first heated air plenum for receiving air from the first heated compartment; and

a first heater blower for forcing air received through the first inlet across the first elongate heating element to produce heated air;

wherein heated air within the first heated air plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across heated food items on meal serving trays in the first heated compartment, upwardly along a forward air return area between the front of the trays and the first door, and to the first heated air plenum inlet where the heated air is cycled back across the first elongate heating element by the first heater blower; and

a second heater for providing heated air to the second heated compartment, said second heater including;

a second heated air plenum having a plurality of through openings for supplying heated air to the second heated compartment;

a second elongate heating element positioned in said second heated air plenum for generating heat;

a second inlet adjacent the top of the cabinet in communication with said second heated air plenum for receiving air from the second heated compartment; and

a second heater blower for forcing air received through the second inlet across the second elongate heating element to produce heated air;

wherein heated air within the second heated air plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across heated food items on meal serving trays in the second heated compartment, upwardly along a forward air return area between the front of the trays and the second door, and to the second heated air plenum inlet where the heated air is cycled back across the second elongate heating element by the second heater blower; and

means for providing refrigerated air the first and second refrigerated compartments.

12. The apparatus of claim 11 wherein each of said first and second elongate heating elements includes a vertically oriented electrical resistance heating element having a length at least as great as 50% of the height of the cabinet.

13. The apparatus of claim 11 wherein said means for providing refrigerated air includes:

a refrigerated air delivery compartment separating the first and second refrigerated compartments said refrigerated air delivery compartment including;

a first refrigeration supply plenum adjacent the first refrigerated compartment and including a plurality of through openings;

a second refrigeration supply plenum adjacent the second refrigerated compartment and including a plurality of through openings;

a refrigeration return plenum having an inlet adjacent the bottom of the cabinet for receiving air from the first and second refrigerated compartments;

a refrigeration coil forming a part of said refrigerator and positioned in said refrigeration return plenum; and

a refrigerator blower for producing and circulating refrigerated air through the first and second refrigerated compartments by causing air within the first and second refrigerated compartments to be passed across the refrigeration coil and provided to the first and second refrigeration supply plenums;

wherein refrigerated air within the first refrigeration supply plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across refrigerated food items on meal serving trays in the first refrigerated compartment, downwardly along a forward air return area between the front of the trays and the first door and a rearward air return area between the back of the trays and the back of the cabinet, and to the refrigeration return plenum inlet where the refrigerated air is cycled back across the refrigeration coil by the blower; and

wherein refrigerated air within the second refrigeration supply plenum is forced out of the plenum through the plurality of through openings and flows substantially laminarly across refrigerated food items on meal serving trays in the second refrigerated compartment, downwardly along a forward air return area between the front of the trays and the second door and a rearward air return area between the back of the trays and the back of the cabinet, and to the refrigeration return plenum inlet where the refrigerated air is cycled back across the refrigeration coil by the blower.

14. The apparatus of claim 11 wherein each of said first and second thermal barriers includes a plurality of thermal dividers vertically arranged within said cabinet to thermally isolate a heated compartment from a refrigerated compartment, wherein each of said dividers is filled with an insulating material.

15. The system of claim 11 wherein each of said food serving trays includes:

a refrigerated food section positioned within a refrigerated compartment;

a heated food section positioned within a heated compartment; and

a tray divider section separating the refrigerated food and heated food sections;

wherein each of said thermal dividers is separated from another thermal divider by a divider gap;

said tray divider section of each meal serving tray being slidably positioned at a divider gap.