WO2003071909A1

WO2003071909A1 - Hot food holding cell and method

Info

Publication number: WO2003071909A1
Application number: PCT/US2003/005183
Authority: WO
Inventors: Keith A. Stanger; Paul Molloy
Original assignee: The Delfield Company
Priority date: 2002-02-22
Filing date: 2003-02-21
Publication date: 2003-09-04
Also published as: AU2003217617A1

Abstract

A hot food well having a hot air convection assembly (50) that heats pans (36) of food suspended in the well (22). The hot air assembly (50) includes a fan (52), a thermally conductive heat sink (60) which is heated by a heater (56) and a baffle (58). The baffle (58) provides a substantially uniform airflow about the pan well (22).

Description

HOT FOOD HOLDING CELL AND METHOD

FIELD OF THE INVENTION This invention relates to a hot food well and method for holding and keeping hot foods warm as in a food service line.

BACKGROUND OF THE INVENTION

Some known hot food wells have used hot water and/or steam to maintain pans of food warm in a food service line. This has required hot water heaters and/or steam generators as well as plumbing and valving. A disadvantage of hot water and/or steam heated food wells is that water contains various minerals that build up a scale on the food well and pan surfaces. Scale cleaning is periodically required and lengthens clean up time. Another disadvantage is that hot water heated food wells consume a lot of energy. A further disadvantage is that the scale, high energy usage, and flowing water result in high maintenance and repair cost.

Other known hot food wells have used either heat by conduction, natural convection or both. These hot food wells also have the disadvantages of high energy usage.

Accordingly, there is a need for an improved hot food well having reduced energy consumption, maintenance cost and clean up time.

SUMMARY OF THE INVENTION

A hot food well of the present invention comprises a pan well that is capable of holding one or more pans and a hot air convection assembly disposed to heat the pans by forced hot air convection.

In a preferred embodiment, the hot air convection assembly comprises a heat sink having a heated surface area and a fan that circulates an airflow along at least a portion of the surface area and among the pans, thereby heating the pans. In an alternate embodiment, the hot air convection assembly further comprises a baffle disposed about the fan to provide a uniform distribution of the airflow about a periphery of the heat sink toward the pans. The baffle preferably surrounds the fan. The baffle preferably comprises a plurality of ports arranged to provide the uniform distribution of air flow.

In another alternate embodiment, the heat sink is disposed in the pan well below the pans. The airflow circulates from the fan along the portion of the surface area and around the heat sink, among the pans and back to the fan via an aperture in the heat sink.

In the other alternate embodiment, the heat sink comprises a metallic sheet having a top and a bottom and the airflow is circulated around a periphery of the heat sink. The fan is preferably disposed in registry with the aperture of the heat sink. A baffle is disposed to provide a uniform distribution of the airflow around the periphery of the heat sink.

In another alternate embodiment, the heat sink comprises a metallic sheet having a bottom and a top, and a plurality of bosses extending from the top. Preferably, the bosses may be disk shaped.

In a further embodiment of the hot food well of the present invention, the pans are also heated by thermal conduction. In this embodiment, the bottoms of the pans are in thermal contact with the heat sink. For example, the heat sink includes one or more bosses in thermal contact with the pan bottoms.

In the above mentioned embodiments, a heater may be disposed to heat the heat sink.

In the above mentioned embodiments, the heat sink is preferably removably disposed in the pan well to facilitate cleaning thereof. The method of the present invention keeps food laden pans warm in a hot food well by circulating an airflow among the pans and heating the airflow, thereby heating the airflow and heating the pans by forced hot air convection.

In one embodiment of the method of the invention, the heating step comprises heating a heat sink disposed in a path of the airflow. Preferably, the circulating step circulates the airflow along a surface of the heat sink.

In another embodiment of the method of the present invention, the circulating step distributes the airflow uniformly around a periphery of the heat sink toward the pans.

In a further embodiment of the method of the present invention, the pans are also heated by thermal conduction.

BRIEF DESCRIPTION OF THE DRAWINGS

Other and further objects, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference characters denote like elements of structure and:

Fig. 1 is a perspective view of a hot food well of the present invention;

Fig. 2 is a cross-sectional view taken along line 2-2 of Fig. 1 ;

Fig. 3 is a cross-sectional view taken along line 3-3 of Fig. 1 ;

Fig. 4 is a perspective and skeletal view of the hot food well of Fig. 1 with the food well wall partially removed; Fig. 5 is a perspective view of the hot food well of Fig. 1 with the pans removed;

Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 4; and

Fig. 7 is a cross-sectional view similar to Fig. 3, but modified for another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Figs. 1 -3, a hot food well 20 according to the present invention comprises a pan well 22 and a pan holding frame 24. Pan well 22 may have any suitable shape and is shown in a preferred rectangular shape. Pan well 22 has four side walls 26, 28, 30 and 32 and a bottom wall 34. Pan holding frame 24 is disposed to hold one or more pans 36 in pan well 22. Preferably, pan holding frame 24 is removably disposed in pan well 22. For example, side walls 26, 28, 30 and 32 may suitably include a ledge 38 disposed near the top thereof. Ledge 38 provides a support surface for pan holding frame 24. It will be apparent to those skilled in the art that alternative forms of removably disposing pan holding frame 24 in pan well 22 may be used.

Pan holding frame 24 can be sized to hold pans 36 of any desired sizes and any desired number. Each pan 36 is provided with a cover 46. Pan holding frame 24 holds pans 36 in suspended relationship so that each pan extends into pan well 22. Each pan 36 includes a lip 48 so that when pan 36 is inserted into pan holding frame 24, lip 48 rests on pan holding frame 24.

Side walls 26, 28, 30 and 32 and bottom wall 34 are similar in construction. For example, bottom wall 34 has an exterior metallic skin 40 and an interior metallic skin 42 with insulation 44 disposed therebetween. This construction provides thermally conductive interior surfaces for pan well 22 as well as protection from thermal loss by insulation 44. Referring to Figs. 2-5, a hot air convection assembly 50 is at least partially disposed in pan well 22 to provide a heated airflow that circulates in and among pans 36, thereby heating pans 36. Hot air convection assembly 50 comprises a fan 52, a fan motor 54, a heater 56, a baffle 58 and a heat sink 60.

Baffle 58 is disposed in pan well 22 and is affixed to bottom wall 34. Baffle 58 includes one or more sections extending upwardly and arranged in a pattern surrounding fan 52. Baffle 58 in the preferred embodiment for a rectangular pan well 22 has a cruciform shape surrounding fan 52 as shown in Fig. 4. It will be apparent to those skilled in the art that other shapes may be used. Baffle 58 has a plurality of ports 62 arranged along its length. Baffle 58 baffles the airflow from fan 52 to provide a substantially uniform air flow. Additionally, baffle 58 provides a support for heater 56 and heat sink 60.

Referring to Fig. 6, baffle 58 preferably comprises a bracket 64 having a vertical portion 66 in which ports 60 are disposed and horizontal portions 66 and 68, which extend from either end of vertical portion 64 in opposite directions. Horizontal portion 66 is affixed to bottom wall 34 by any suitable fastener (not shown). For example, the fastener might be a screw, bolt, weldment and the like. Horizontal portion 68 provides a support for heater 56, which may be fastened thereto by any suitable fastener that permits easy replacement of heater 56. For example, the fastener may be a clamp 70 fastened by screws to horizontal portion 68. Baffle 58 and clamp 70 may suitably be a metal, such as stainless steel.

Heater 56 is preferably an electrical heater in the form of one or more elements wound in a pattern that has substantial exposure to the airflow from fan 52. As noted above, the heater element 56 (or elements) is fastened to baffle 58. For example, heater 56 may be a tubular and/or sheath type heater. Those skilled in the art will appreciate that other heaters, electric or gas, may be used.

Referring to Figs. 2, 3 and 5, heat sink 60 comprises a thermally conductive sheet 74 having a bottom surface 76, a top surface 78 and a plurality of thermally conductive bosses 80 extending upwardly from top surface 78. Preferably, bosses 80 are disk shaped. Heat sink 60 is removably disposed in pan well 22 above baffle 58 and heater 56 so that bottom surface 76 rests on clamp (or clamps 70) so as to be in good thermal transfer with heater 56. Heat sink 60 is sized to form a gap 72 (Figs. 2 and 3) between the edges thereof and an inside periphery of pan well 22.

Bosses 80 are arranged so as to provide substantial exposure to the airflow from fan 52. Preferably, bosses 80 are arranged slightly inwardly of the edges of heat sink 60. Bosses 80 are preferably metallic so as to have good thermal conductivity. Bosses 80 may be formed integrally with top surface 78 or may be attached thereto by any suitable fastener, such as a screw, a bolt, a weldment and the like.

Fan 52 is disposed in pan well 22 in registry with an aperture 82 that is disposed in heat sink 60. Fan 52 is preferably a forward incline fan. Fan 52 is driven by fan motor 54 that is coupled to fan 52 by a shaft 84. A fan cover 86 is disposed above fan 52 and aperture 82 so as to provide a gap 88 for a suction inlet for the air flow, gap 88 being between top surface 78 of heat sink 60 and fan cover 86. Heat sink 60, bosses 80 and fan cover 86 are preferably aluminum, but may alternately be any suitable metal having good thermal conductivity.

With pans 36 installed, fan 52 provides an airflow that circulates under heat sink 60, through baffle 58, upwardly through gap 72, in and among pans 36 and through gap 88 to back to fan 52 as shown by the arrows in Figs. 2 and 3. Heater 56 heats heat sink 60 to provide a large heated surface area (bottom surface 76, top surface 78 and bosses 80 for heating the airflow. Baffle 58 baffles the airflow to provide a substantially uniform airflow through gap 72 to pans 36. If a pan 36 is empty, the efficiency and energy consumption can be improved by placing a cover 46 thereon.

A controller 92 controls the operation of fan 52, heater 56 and an axial fan 90. A temperature probe 94 is provided in pan well 22 to provide a signal indicative of sensed temperature in pan well 22. Controller 92, for example, uses the temperature probe signal to operate fan 52 and heater 56 to maintain the temperature of pan well 22 at a desired temperature.

Controller 92, fan motor 54 and axial fan 90 are disposed in a control box 96 located adjacent bottom wall 34 of pan well 22. Axial fan 90 provides cooling to controller 92, motor 54 and other parts (not shown) that may be located in control box 96.

Referring to Fig. 7, another embodiment of the hot food well 20 of the present invention provides cooling by both forced hot air convection as well as by thermal conduction. In this embodiment, the heights of bosses 80, fan cover 86 and pans 36 are dimensioned so that the bottoms of pans 36 are in thermal contact with either a boss 80 or fan cover 86. Thus, pans 36 are heated by both the forced hot air convection provided by heat sink 60 and fan 52 as well as by conduction due to thermal contact with one or more bosses 80 and/or fan cover 86.

Thus, hot food well 20 of the present invention has easily removable pans 36, pan holding frame 24 and heat sink 60 for periodic cleaning purposes. Hot food well 20, as compared to a traditional hot water heated food well, has a 57% reduction in energy consumption and reduced maintenance due to elimination of a heated water bath and scale problem.

The present invention having been thus described with particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A hot food well comprising:

a pan well that is capable of holding one or more pans; and

a hot air convection assembly disposed to heat said pans by forced hot air convection.

2. The hot food well of claim 1 , wherein said hot air convection assembly comprises a heat sink and a fan that circulates an airflow along at least a portion of said heat sink and among said pans, thereby heating said airflow and said pans.

3. The hot food well of claim 2, wherein said hot air convection assembly further comprises a baffle disposed about said fan to provide a uniform distribution of said airflow about a periphery of said heat sink toward said pans.

4. The hot food well of claim 3, wherein said baffle surrounds said fan.

5. The hot food well of claim 3, wherein said baffle comprises a plurality of ports arranged to provide said uniform distribution of air flow.

6. The hot food well of claim 2, wherein said heat sink is disposed in said pan well below said pans, and wherein said airflow circulates from said fan along said portion of said heat sink and around said heat sink, among said pans and back to said fan via an aperture in said heat sink.

7. The hot food well of claim 6, wherein said fan is disposed in registry with said aperture.

8. The hot food well of claim 6, wherein said heat sink comprises a metallic sheet having a top and a bottom that corresponds to said portion.

9. The hot food well of claim 8, wherein said airflow is circulated around a periphery of said heat sink.

10. The hot food well of claim 9, wherein said fan is disposed in registry with said aperture.

11. The hot food well of claim 10, wherein said hot air convection assembly further comprises a fan cover located above said top and said aperture.

12. The hot food well of claim 11 , wherein said hot air convection assembly further comprises a baffle disposed to provide a uniform distribution of said airflow around said periphery of said heat sink.

13. The hot food well of claim 2, wherein said heat sink comprises a metallic sheet having a bottom and a top, and a plurality of bosses extending from said top.

14. The hot food well of claim 2, wherein said hot air convection assembly further comprises a heater disposed to heat said heat sink.

15. The hot food well of claim 2, wherein said heat sink is removably disposed in said pan well to facilitate cleaning thereof.

16. The hot food well of claim 2, wherein said pans are in thermal contact with said heat sink so as to also be heated by thermal conduction

17. The hot food well of claim 16, wherein each of said pans has a bottom that is in contact with said heat sink.

18. The hot food well of claim 17, wherein said heat sink includes one or more bosses that make thermal contact with said bottoms of the pans.

19. A method of keeping food laden pans warm in a hot food well, comprising:

circulating an airflow among said pans; and

heating said airflow, thereby heating said pans by forced hot air convection.

20. The method of claim 19, wherein said heating step comprises heating a heat sink disposed in a path of said airflow.

21. The method of claim 20, wherein said circulating step circulates said airflow along a surface of said heat sink, thereby heating said airflow.

22. The method of claim 20, wherein said circulating step distributes said airflow uniformly around a periphery of said heat sink toward said pans.

23. The method of claim 19, further comprising heating said pans by thermal conduction.

24. The method of claim 23, wherein said heating step comprises heating a heat sink disposed in a path of said airflow, and wherein said heat sink includes one or more bosses in thermal contact with said pans.