Abstract:
A food holding cabinet for holding and keeping hot food safe and fresh at a desired temperature until ready to be served. Radiant heaters disposed in food compartment walls supply radiant heat to the interior of the food holding compartment. The radiant heat is transferred from the radiant heaters via metallic heat sink plates. The radiant heat is supplied from two vertical walls and one horizontal wall to provide a uniformity of heat distribution across all tray levels.

Description:
CROSS-REFERENCED APPLICATIONS 
       [0001]    This application is a National Stage Application of PCT/US2011/062108, filed on Nov. 23, 2011, which claims priority to US Provisional Application No. 61/537529, filed on Sep. 21, 2011, both of which are incorporated in their entireties by reference thereto. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    This disclosure relates to a food holding cabinet and method for holding and keeping hot pre-cooked food safe and fresh at a desired temperature until it is ready to be served. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    Food holding cabinets are used to keep pre-cooked food hot. Some known food holding cabinets have been characterized with uneven distribution of heat transferred into the food holding compartment. A challenge is to retain moisture in the food while keeping the food warm. Some known food holding cabinets use a hot air blowing method. Moisture injection is sometimes used to maintain a proper humidity in the food compartment. These methods require adding a fan box and/or moisture generating capability. This adds manufacturing expense, extra size, extra maintenance and extra power consumption. 
         [0004]    There is a need for a food holding cabinet and method that provides uniform heat distribution at all levels within the food holding compartment. 
         [0005]    There is also a need for a food holding cabinet and method that retains moisture in the food and the flavor of the original taste without using a moving hot air stream with moisture injection. 
       SUMMARY OF THE DISCLOSURE 
       [0006]    A holding cabinet for holding hot food according to one embodiment of the present disclosure comprises a plurality of walls that define a compartment having a holding structure for holding hot food. One or more of the walls comprises an internal panel and an external panel. A radiant heating element is disposed in a space between the internal panel and the external panel. A heat sink plate is disposed in the space in contact with the internal panel such that radiant heat is transferred from the radiant heating element via the heat sink plate and the internal panel into an interior of the compartment. 
         [0007]    In another embodiment of a holding cabinet for holding hot food according to the present disclosure, the heat sink plate is selected from the group consisting of: aluminum, an alloy of aluminum and other metal. 
         [0008]    In another embodiment of a holding cabinet for holding hot food according to the present disclosure, the radiant heating element comprises at least one silicon heating pad. 
         [0009]    In another embodiment of a holding cabinet for holding hot food according to the present disclosure, a plate is disposed in the space that presses the radiant heating element against the heat sink plate. 
         [0010]    In another embodiment of a holding cabinet for holding hot food according to the present disclosure, thermal insulation is disposed between the plate and the radiant heating element. 
         [0011]    In another embodiment of a holding cabinet for holding hot food according to the present disclosure, the one or more walls is selected from the group consisting of: one vertical wall, two vertical walls, one vertical wall and one horizontal wall, two vertical walls and one horizontal wall, and two vertical walls and two horizontal walls. 
         [0012]    In another embodiment of a holding cabinet for holding hot food according to the present disclosure, the one or more walls provide radiant heat flow horizontally and vertically within the compartment. 
         [0013]    In another embodiment of a holding cabinet for holding hot food according to the present disclosure, a door is provided for the compartment and an adjustable vent to ambient is disposed in the door to control uniformity of heat distribution within the compartment. 
         [0014]    A method according to the present disclosure keeps pre-heated food warm in a closed compartment of a holding cabinet, by: 
         [0015]    providing radiant heat vertically and horizontally to the compartment; and 
         [0016]    controlling uniformity of the radiant heat within the compartment. 
         [0017]    In another embodiment of the method of the present disclosure, the providing step comprises: transferring the radiant heat from one or more radiant heating elements via one or more heat sink plates to the compartment. 
         [0018]    In another embodiment of the method of the present disclosure, at least one of the radiant heating elements is flush against at least one of the heat sink plates. 
         [0019]    In another embodiment of the method of the present disclosure, the controlling step comprises: adjusting a vent to ambient disposed on the compartment. 
         [0020]    In another embodiment of the method of the present disclosure, the vent is disposed in a door of the compartment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    Other and further objects, advantages and features of the present disclosure 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: 
           [0022]      FIG. 1  is a perspective view of a food holding cabinet according to the present disclosure; 
           [0023]      FIG. 2  is a front view of the food holding cabinet of  FIG. 1  with doors removed; 
           [0024]      FIG. 3  is a cross-sectional view taken along line  3  of  FIG. 2 ; 
           [0025]      FIG. 4  is an enlarged view of detail A of  FIG. 3 ; and 
           [0026]      FIG. 5  is an exploded perspective view of a sidewall of the holding cabinet of  FIG. 1 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0027]    Referring to  FIGS. 1 and 2 , a food holding cabinet  20  according to the present disclosure comprises an upper section  22  and a lower section  24 . Upper section  22  comprises sidewalls  26  and  28 , a back wall  29 , a top wall  30  and a wall  32 , which define an upper compartment  34 . Lower section  24  comprises sidewalls  36  and  38 , a back wall  39 , a bottom wall  40  and wall  32 , which define a lower compartment  42 . Wall  32  serves as a bottom wall for upper compartment  34  and as a top wall for lower compartment  42 . 
         [0028]    An upper door  44  is attached to sidewall  26  of upper compartment  34  with hinges  46 . A lower door  48  is attached to sidewall  36  of lower compartment  42  with hinges  50 . Upper and lower doors  44  and  48  have handles  52  and  54 , respectively. Gaskets  78  are mounted on upper and lower doors  44  and  48 . Upper and lower doors  44  and  48  also comprise air pressure adjusters  56  and  58 , respectively. Air pressure adjusters  56  and  58 , for example, may be manually operated slider vents that vent air within upper and lower compartments  34  and  42  to ambient. 
         [0029]    Food holding cabinet  20  further comprises a control section  60  mounted above upper compartment  34 . Control section  60  includes a control panel  62  that has temperature adjusting knobs  64  and  66  for upper and lower compartments  34  and  42 , respectively. Control section  60  further includes various control items, such as connections to temperature sensors (not shown) disposed in upper and lower compartments  34  and  42  to allow temperature adjustments, to a power source (not shown), e.g., a conventional ac electrical power source and the like. 
         [0030]    A plurality of caster wheels  68  is fastened to a bottom of food holding cabinet  20 . The caster wheels  68  fastened to the back are rigid without brakes and the caster wheels  68  fastened to the front are swivel with brakes. 
         [0031]    Tray holding racks  70  and  72  are mounted to interior surfaces of side walls  26  and  28 , respectively, of upper compartment  34  and tray holding racks  74  and  76  are mounted to interior surfaces of sidewalls  36  and  38 , respectively, of lower compartment  42 . Upper tray racks  70  and  72  are smaller in depth than lower tray tracks  74  and  76  in order to handle larger tray sizes (for example, 20.9 inches by 25.6 inches). On the other hand, lower tray tracks  74  and  76  handle smaller trays (for example, 18 inches by 25.6 inches). It will be appreciated that in some embodiments tray racks  70  and  72  can be sized for tray sizes other than the above examples or even sized equally for same sized trays. 
         [0032]    Sidewalls  26 ,  28 ,  36  and  38 , wall  32  and bottom wall  40  are substantially identical to one another. Because of this, only sidewall  28  will be described in detail. 
         [0033]    Referring to  FIGS. 3-5 , sidewall  28  comprises an external panel  80  and an internal panel  82 . A pair of rails  110  and  112  (shown in  FIG. 5 ) are mounted near opposite vertical edges of an interior surface of internal panel  82 . A heat sink plate  84  is disposed between rails  110  and  112  on the interior surface of internal panel  82  in a space  86  between external panel  80  and internal panel  82 . Preferably, heat sink plate  84  has a surface that is mounted flush to the interior surface of internal panel  82 . A heating element  90  is disposed in space  86  and has a surface flush to an opposite surface of heat sink plate  84 . A plate  92  is disposed in space  86  and is mounted flush to an opposite surface of heating element  90 . 
         [0034]    An insulation layer  98 , a plate cover  94 , an insulation layer  100 , a frame  108  and external panel  80  extend vertically of sidewalls  28  and  38 . Plate cover  94  is disposed in space  86  parallel to external panel  80  and internal panel  82  to form a region  96  in each sidewall  28  and  38  between plate  92  and plate cover  94 . Three bosses  88  extend from heat sink plate  84  in region  96  to physical contact with plate cover  94 . Bosses  88  are positioned to hold heating element  90  in a desired location on heat sink plate  84 . In the illustrated embodiment, one boss  88  is located near a bottom edge of heat sink plate  84  and the other two bosses  88  are located near opposite vertical edges of heat sink plate  84 . 
         [0035]    A slot  85  is positioned adjacent a vertical edge of heating element  90  in a mating relationship with the boss  88  adjacent a vertical edge of heat sink plate  84 . Plate  92  also has a notch  91  that is positioned on a vertical edge so as to be in registry with slot  85  of heating element  90  and the boss  88  adjacent a vertical edge of plate  92 . A frame  102  extends from a bottom edge and the vertical edges of plate  92  in region  96  to physical contact with plate cover  94 . A thermal insulation layer  98  is disposed in region  96  in sufficient amount to press or clamp plate  92 , heating element  90 , heat sink plate  84  and internal panel  82  together in the aforementioned flush relationships. An insulation layer  100  is disposed in space  86  between external panel  80  and plate cover  94  in sufficient amount to press or clamp plate cover  94  to bosses  88  of heat sink plate  84  and a frame  102  of plate  92 . 
         [0036]    Preferably, heating element  90  and heat sink plate  84  cover a substantial portion of internal panel  82 . Heating element  90  comprises a radiant heating element that provides radiant heat in a medium wavelength range of 5 to 8 micrometers. One example of a preferred radiant heating element  90  is a silicon heater pad, available from Alden Works as model no. R30-653 &amp; R30-654. Heat sink plate  84  is preferably a metal plate, for example, aluminum or other metal that is capable of transferring radiant heat from heating element  90  into upper compartment  34 . 
         [0037]    External panel  80 , internal panel  82  and frame  108  are preferably a suitable metal, such as stainless steel. Plate  92  and plate cover  94  are preferably a galvanized metal. Insulation layer  98  is preferably a thermal insulation, such as ceramic wool insulation. Insulation layer  100  is preferably a thermal insulation, such as rock wool insulation. 
         [0038]    When connected to a source of electrical energy, heating element  90  emits radiant heat, which is transferred via heat sink plate  84  into upper compartment  34  or lower compartment  42 . In the preferred embodiment, radiant heat is supplied both horizontally and vertically in upper and/or lower compartments  34  and  42 . Preferably, the radiant heat is supplied from both sidewalls  26  and  28  and bottom wall  32  in upper compartment  34 . In lower compartment  42 , the radiant heat is supplied from both sidewalls  36  and  38  and bottom wall  40 . For this embodiment, the radiant heat flow is as shown in  FIG. 2  by horizontal arrows  104  and vertical arrows  106 . In this embodiment, the hot air is distributed uniformly across all tray levels within upper compartment  34  and lower compartment  42 . This distribution is assisted by air pressure adjusters  56  and  58 , which vent hot air to ambient as well as control the air pressure within the upper and lower compartments  34  and  42 . 
         [0039]    In other embodiments, heat can be supplied from one vertical wall, two vertical walls, one vertical wall and one horizontal wall, and two vertical walls and two horizontal walls. 
         [0040]    Temperature adjuster knobs  64  and  66  are manually operable to set the temperature in upper and lower compartments  34  and  42 . Upper and lower temperature sensors (not shown) are located in upper compartment  34  and lower compartment  42 , respectively, and provide a temperature signal to control section  60 . A control unit (not shown) in control section  60  responds to the temperature signal to operate the heating elements  90  to attain and maintain the set temperature within upper and lower compartments  34  and  42 . Separate temperature adjuster knobs  64  and  66  allow different temperatures to be set in upper and lower compartments  34  and  42 , so as to accommodate different food types in food holding cabinet  20 . 
         [0041]    The present disclosure 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 disclosure as defined in the appended claims.