Abstract:
A refrigeration system for maintaining edible substances at a low temperature of the present invention includes a serving pan, an element for retaining or holding the serving pan, and a refrigeration tube and a glycol medium surrounding the pan is disclosed. The refrigeration tube and glycol medium act together in order to maintain the pan at a low temperature for a prolonged period of time and to provide an even cooling of the pan. In a second embodiment, the refrigeration tube may be surrounded by the glycol medium. In a further embodiment, the system may be used to heat food rather than to cool food by using a heat pump alone or in combination with electric heating elements. In yet another embodiment, the glycol medium may surround only the sides or only the bottom of the pan.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation-In-Part of co-pending International Application No. PCT/US00/11982, filed May 2, 2000 which is a Continuation of U.S. patent application Ser. No. 09/303,757, filed May 3, 1999 now U.S. Pat. No. 6,085,535 and U.S. patent application Ser. No. 09/505,826, filed Feb. 17, 2000 now U.S. Pat. No. 6,145,333. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention is directed toward refrigeration and heating systems to be used in the food service industry and more particularly, toward serving pans and the like which are maintained at a low or a high temperature for prolonged periods of time and that are cooled or heated uniformly. 
     A problem facing many businesses in the food industry is the inability to maintain the temperature of foods meant to be kept cold or, particularly in a salad bar type of setting or in other settings where it may be necessary to keep foods chilled for extended periods of time after they have been removed from normal refrigeration facilities. Particularly difficult is the inability to maintain cold temperatures at the upper level of the foods which is require by the health authorities. That is, while it is normally too difficult to maintain salad or the like located near the bottom of a serving pan at a relatively cold temperature, it is difficult to maintain salad or a similar food at the top of the pan at an equally cold temperature. 
     In one type of salad bar arrangement, for example, shallow pans are placed within wells of a cabinet or service counter. The crocks or containers of food or food itself is then placed within the pans and crushed ice is then placed around the containers or the food. Alternatively, the ice may be placed within the pans first and then the containers may be placed in the ice. A problem with this type of arrangement is that it is difficult to maintain a suitable temperature for the food. That is, as the ice melts, it is necessary to continuously refill the pans with ice in order to maintain an appropriate temperature. This type of refrigeration system also requires constant supervision and maintenance. 
     Another typical salad bar has a refrigeration coil under the pans holding the crocks or containers of food or the food. Again, the problem with this type of system is that it is difficult to maintain a suitable temperature. That is, the food either freezes if it directly overlies a refrigeration coil or becomes too warm. Furthermore, the cooling tends not to be uniformly distributed to all of the food or containers particularly near the top of the pan. In these types of arrangements, in order to lower the temperature sufficiently near the top of the pan, the refrigeration coils must be so cold that food at the bottom of the pan which may be in close proximity to the coils freezes or deteriorates as a result of the very cold temperature. 
     U.S. Pat. No. 5,247,807 to Jarman et al. discloses a refrigerated condiments container which can be used in a salad bar. The container rests within a chamber which has refrigeration coils. The problem with this system, however, is that it is difficult to maintain a suitable temperature for the food. Also, the containers are not cooled uniformly, therefore the food within the containers is not kept cold with uniformity. 
     U.S. Pat. No. 4,989,419 to Brando et al. discloses a food service tray having a top tray and a bottom tray with a container being held within a hollow member formed in the top tray. The top tray and bottom tray form a chamber therebetween which is filled with a gel in order to keep the container chilled for an extended period of time. The problem with this type of system is that the use of gel still does not allow the food to be maintained at a low enough temperature as there is no way of continuously refrigerating the gel. 
     SUMMARY OF THE INVENTION 
     The present invention is designed to overcome the deficiencies of the prior art discussed above. It is an object of the present invention to provide a refrigeration system for maintaining serving pans and the like at temperatures lower than prior art systems are capable of maintaining. 
     It is another object of the present invention to provide a refrigeration system which allows serving pans to be maintained at a low temperature for a prolonged period of time. 
     It is a further object of the present invention to provide a refrigeration system which allows uniform cooling of serving pans and which allows food near the top of a pan to be cooled without injuring the food near the bottom. 
     It is another object of the present invention to provide a heating system which allows uniform heating of serving pans and which allows food near the top of a pan to be heated without injuring the food near the bottom. 
     In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a refrigeration system which maintains serving pans and the like at a temperature that is lower than the temperature at which prior art pans are maintained. The system includes a pan which fits into a well of a counter or cabinet. The pan includes a compartment within which food is kept. This compartment is surrounded by a layer of glycol medium and surrounding this layer is a refrigeration tube which is surrounded by insulation. 
     In an alternative embodiment of the present invention, the refrigeration tube may be located within the glycol medium. 
     In yet another embodiment, a heat pump and/or electric heating elements may used in either of the embodiments described above. 
     In another embodiment, the glycol medium may surround only the sides or bottom of the pan in any of the embodiments described above. 
     Other objects, features, and advantages of the invention will be readily apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of illustrating the invention, there is shown in the accompanying drawings forms which are presently preferred; it being understood that the invention is not intended to be limited to the precise arrangements and instrumentalities shown. 
     FIG. 1 is a perspective view of a pan of the present invention placed within the well of a counter; 
     FIG. 2 is an exploded view of the pan and the counter of the present invention; 
     FIG. 3 is a cross-sectional view taken along line  3 — 3  of FIG. 1; 
     FIG. 4 is an exploded, cross-sectional view of a portion of the pan of the present invention; 
     FIG. 5 is a cross-sectional view of a second embodiment of the present invention; 
     FIG. 6 is a cross-sectional view of another embodiment of the present invention; and 
     FIG. 7 is a cross-sectional view of a further embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings in detail wherein like reference numerals have been used throughout the various figures to designate like elements, there is shown in FIG. 1 a refrigeration system constructed in accordance with the principles of the present invention and designated generally as  10 . 
     The refrigeration system  10  of the present invention includes a serving pan  12  or any other type of means for holding edible substances. The pan  12  may be made from stainless steel or any other type of metal or other material which is typically used in the food service industry. While the pan  12  has been shown as being generally rectangular, it should be understood that this is merely for illustration purposes and that a pan of substantially any shape may be used. The pan  12  includes a first compartment  14  for holding food and has an inner wall  16  and an outer wall  18 . Secured to the uppermost portions of the inner and outer walls  16  and  18  and extending along the periphery of the pan  12  is a flange  20 . The purpose of the flange  20  will be discussed in greater detail below. 
     Surrounding the bottom and sides of the first compartment  14  is a glycol medium  22  which is contained within a second compartment  24  bounded by walls  18  and  25 . Surrounding the wall  25  which forms the bottom and sides of the second compartment  24  is a third compartment  26  containing a refrigeration tube  28  preferably in the form of a coil or the like. The refrigeration coil  28  is surrounded by insulation  30  which, in turn, is bounded by outer wall  27  of the pan  12 . (See FIG. 3.) 
     Refrigeration coil  28  is preferably comprised of copper tubing or the like filled with a coolant such as Freon or similar material and is welded or otherwise securely affixed directly to the outer surface of wall  25 . Although not specifically shown, it will be understood that the coil  28  is connected to a refrigeration system in order to continuously or intermittently chill the liquid or gas within the coil. This is preferably done utilizing flexible tubing or the like so that the pan  12  can be lifted up or moved for cleaning or other purposes as shown in FIG.  2 . The walls  16 ,  25  and  27  of compartments  14 ,  24 , and  26  are preferably made of stainless steel or similar metal and are secured to each other by welding or any other type of securing means well known in the art. Alternatively, the coil  28  need not be affixed to the outer surface of the wall  25 . 
     The pan  12  fits within a well  32  of a metal counter or cabinet  34  or any other type of means for retaining a serving pan with the flange  20  resting on the top surface  36  of the counter  34  so that the pan  12  is removably held within the well  32 . Secured to the uppermost part of the inner wall  16  and along the top wall  38  which connects inner wall  16  to outermost wall  27  of pan  12  is a plastic breaker strip  40 . The flange  20  is secured to the plastic strip  40  by any means well known in the art, such as heat sealing or through the use of adhesives or the like. The breaker strip  40  acts as an insulator for the pan  12  by separating the metal flange  20  from the metal inner wall  16  and metal top wall  38 . 
     As should be readily apparent to those skilled in the art, by thermally separating the flange  20  from the walls  16  and  38 , heat is prevented from being transferred between the top surface  36  of the counter  34  and the walls  16  and  38 . That is, if the pan  12  were set into the well  32  of the counter  34 , with the flange  20  directly contacting the top surface  36  of the counter  34  and the inner and top walls  16  and  18 , the counter  34  would act as a heat sink so that heat would transfer from the counter to the pan  12 . The flange  20  and breaker strip  40  prevent this dissipation of heat by creating a separation between the operational parts of the pan  12  and the top surface  36  of the counter  34 . Thus, cold is retained by the pan  12 . 
     Extending through the outermost wall  27  of the pan  12  at a position downwardly from the top wall  38  is a fill tube  44  which extends through the third compartment  26  and is used to fill the second compartment  24  with the glycol medium or similar gel or solution  22 . The outside end of the tube  44  is closed by a cap  46  so that once the second compartment  24  has been filled, the tube  44  may be closed. (See FIG. 4.) Another tube  48  is located on another side of the pan  12  and is used as an air vent during the filling of the second compartment. The outside end of tube  48  may also be covered with a cap  50  when not in use. A drain tube  52  extends from the bottom of the first compartment  14  through the walls  16 ,  25  and  27  in order to drain any excess moisture or liquid they may accumulate. The drain tube  52  can either be connected to a flexible drain line or pass through an opening  54  in the wall  56  at the bottom of the well  34 . 
     In the present invention, the refrigeration tube  28  and glycol medium  22  act together as means for more uniformly distributing the refrigeration and maintaining the pan at a lower temperature for a prolonged period of time. The location of the refrigeration tube and medium provides for a more uniform cooling of the pan in that cold is first transferred from the coil  28  to the wall  25 , then to the glycol  22  and then to the inner wall  16 . The present system also provides for maintaining a much lower temperature than prior art refrigeration systems of the same type without fear of spoiling food that would otherwise come into closer contact with a refrigeration coil. As a result, edible substances may be maintained within the pan at more uniform and lower temperatures for a prolonged period of time. Thus, less maintenance and supervision of the pan is required. 
     A second embodiment of the present invention is shown in FIG.  5 . The structure of the system  210  described in this embodiment differs from the system of the first embodiment only to the extent discussed below. All other structural and functional aspects of the two systems are identical and will not be repeated here. 
     In this embodiment the serving pan includes a first compartment  214  for holding food and has an inner wall  216  and an outer wall  218 . Surrounding the bottom and sides of the first compartment  214  is a glycol medium  222  which is contained within a second compartment  224  bounded by walls  218  and  225 . Located within compartment  224  is a refrigeration tube  228  preferably in the form of a coil or the like. Surrounding the wall  225  which forms the bottom and sides of the second compartment  224  is a third compartment  226  which is bounded by outer wall  227  of the pan. 
     Refrigeration coil  228  is preferably comprised of copper tubing or the like and is filled with a coolant as described above. The coil  228  may be welded or otherwise securely affixed directly to the inner surface of wall  225 . Alternatively, the coil  228  need not be affixed to the wall  225 . Although not specifically shown, it should be understood that the coil  228  is connected to a refrigeration system in order to continuously or intermittently chill liquid or gas within the coil. 
     In either embodiment described above, a heat pump may be used to supply a heating system rather than a refrigeration system. That is, the refrigeration coil may be filled with a heated fluid. The system is then reversed in order to heat the medium  22  or  222  rather than to chill the same. The refrigeration system may act as a heat pump so that hot fluid is pumped through the coils. Alternatively, hot fluid may be supplied by a boiler system or other sources of heated fluid. Furthermore, in addition to or in lieu of the coils, electric resistance wires or other heating elements may be used in the system to heat the medium  22  or  222 . 
     A further embodiment of the present invention is shown in FIG.  6 . The structure of the system  310  described in this embodiment differs from the system of the first embodiment only to the extent discussed below. All other structural and functional aspects of the two systems are identical and will not be repeated here. 
     The refrigeration system  310  includes a serving pan or any other type of means for holding edible substances as described in the previous embodiments. The pan includes a first compartment  314  for holding food and has an inner wall  316  and an outer wall  318 . Secured to the uppermost portions of the inner and outer walls  316  and  318  and extending along the periphery of the pan is a flange  320 . 
     Surrounding only the sides or only the bottom of the first compartment  314  is a glycol medium  322  which is contained within a second compartment  324  bounded by walls  318  and  325 . Surrounding the wall  325  which forms the bottom and the sides of the second compartment  324  is a third compartment  326  containing a refrigeration coil  328 . The refrigeration coil  328  is surrounded by insulation  330  which, in turn, is bounded by outer wall  327  of the pan. 
     Yet a further embodiment of the present invention is shown in FIG.  7 . The structure of the system  410  described in this embodiment differs from the system of the second embodiment only to the extent discussed below. All other structural and functional aspects of the two systems are identical and will not be repeated here. 
     In this embodiment the serving pan includes a first compartment  414  for holding food and has an inner wall  416  and an outer wall  418 . Surrounding either only the sides or only the bottom of the first compartment  414  is a glycol medium  422  which is contained within a second compartment  424  bounded by walls  418  and  425 . Located within compartment  424  is a refrigeration tube  428  preferably in the form of a coil or the like. Surrounding the wall  425  which forms the bottom and the sides of the second compartment  424  is a third compartment  426  which is bounded by outer wall  427  of the pan. 
     Refrigeration coil  428  is preferably comprised of copper tubing or the like and is filled with a coolant as described above. The coil  428  may be welded or otherwise securely affixed directly to the inner surface of wall  425 . Alternatively, the coil  428  need not be affixed to the wall  425 . Although not specifically shown, it should be understood that the coil  428  is connected to a refrigeration system in order to continuously or intermittently chill liquid or gas within the coil. 
     In either embodiment shown in FIGS. 6 and 7, a heat pump may be used to supply a heating system rather than a refrigeration system, as described above with regard to the first and second embodiments. 
     The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and accordingly, reference should be made to the appended claims rather than to the foregoing specification as indicating the scope of the invention.