Abstract:
A food preparation table for preparing food and refrigerating foodstuffs includes at least one open top food container for holding foodstuffs, a cooling device for absorbing heat from air, an accelerating device for forcing the air to flow and an air supplying device for making a first portion of the air flow around said at least one open top food container and a second portion of the air stacked above the foodstuffs contained in said at least one said at least one open top food container.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a cooling system for use in a food preparation table having open top food containers; and, more particularly, to a cooling system for use in the food preparation table capable of making temperature of the foodstuffs remain in a preferred temperature range by using cold air to keep foodstuffs refrigerated freshly for a long time. 
     BACKGROUND OF THE INVENTION 
     Food preparation tables are generally installed in restaurants and sandwich stores and include more than one open top food containers for holding various refrigerated foodstuffs. The refrigerated foodstuffs include usually various kinds of vegetables, hams, cheeses, etc. In order to keep those stuffs fresh for a long time, the temperature thereof has to be maintained between certain temperatures, e.g., 32° F. and 40° F., a temperature range promulgated by National Sanitation Foundation (NSF). 
     But, since the foodstuffs in the food containers are usually exposed to the ambient air whose temperature tends to be above the temperature range promulgated by NSF, the ambient air supplies heat to the foodstuffs. Therefore, if the food preparation table does not get rid of the heat supplied to the foodstuffs by the ambient air, the temperature of the foodstuffs reaches rapidly to that of the ambient air. 
     To remove the heat transferred to the foodstuffs, the food preparation tables has usually adopted two kinds of methods. One is to employ cold wall refrigeration enclosures around the food containers. The other is to blow cold air onto the foodstuffs and the food container so that the cold air can absorb heat from the foodstuffs and form an air curtain above the foodstuffs to thereby prevent heat from being transferred to the foodstuffs from the ambient air. 
     The first method causes some parts of the foodstuffs to be frozen. So the second method has been widely employed in the food preparation tables. One of such food preparation tables employing the second method is disclosed in U.S. Pat. No. 5,168,719 issued to Branz. In Branz&#39;s device, cold air supplied from a cold air supplying passage disposed around the food containers flows above the foodstuffs contained in the food containers and then enters into a food-storage compartment through a re-entry passage disposed opposite to the cold air supplying passage. 
     However, when the cold air supplied above the foodstuffs enters into the food storage compartment through re-entry passage disposed opposite to the cold air supplying passage, ambient air also enters there. Further, the cold air passing above the foodstuffs contained in the food container absorbs heat from the ambient air as well as the foodstuffs. Accordingly, an apparatus for cooling air, which circulates in the food-preparation table, consumes more electricity than actually needed. 
     In addition, an apparatus for supplying the cold air consumes large amount of electricity in order to form an air curtain between the foodstuffs and the ambient air by jetting the cold air since the apparatus for supplying the cold air needs to jet the cold air without stopping. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a more efficient food preparation table with open top food containers than conventional ones. 
     In accordance with one aspect of the invention, there is provided a food preparation table for preparing food and refrigerating foodstuffs including: 
     at least one open top food container for holding foodstuffs; 
     a cooling device for absorbing heat from air; 
     an accelerating device for forcing the air to flow; and 
     an air-supplying device for making a first portion of the air flow around the open top food container and a second portion of the air stacked above the foodstuffs contained in the open top food container. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects and features of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawings, in which: 
     FIG. 1 shows a perspective view of a food preparation table in accordance with a preferred embodiment of the present invention; 
     FIG. 2 illustrates a cross sectional view taken along the line  2 — 2  in FIG. 1; 
     FIG. 3 describes a cross sectional view taken along the line  3 — 3  in FIG. 1; 
     FIG. 4 offers a perspective exploded view of parts constituting the cooling system of the food preparation table in accordance with the preferred embodiment of the present invention; 
     FIG. 5 provides a cross view of the food preparation table in accordance with the preferred embodiment of the present invention indicating the direction of air flows by the arrows; and 
     FIG. 6 provides a top view of the food preparation table in accordance with the preferred embodiment of the present invention indicating the direction of air flows by the arrows. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, there is shown a perspective view of a food preparation table in accordance with a preferred embodiment of the present invention. The food preparation table  10  for preparing food and refrigerating foodstuffs includes a pair of doors  11 , a counter top  17 , a food container support  13  inserted in a hole formed in the counter top  17 , four open top food containers  12  rested on a ledge  213  (shown in FIG. 2) of the food container support  13  and a cover  14  rotatably fixed to a cover support  27 . 
     As shown in FIG. 2, the food preparation table  10  also includes a food storage compartment  15  for rendering foodstuffs refrigerated therein and a cooling system for keeping foodstuffs  43  in the food containers  12  refrigerated freshly for a long time. 
     The cooling system has an evaporator  35  absorbing heat from circulating air (indicated by arrows) passing across it, a condenser  51 , a compressor  52 , a pair of fans  33  respectively rotated by motors  34 , an air distributing chamber  40  disposed in front of the fans  33 , an air room  41  formed above the air distributing member  40  and in contact with the food container support  13 , a barrier plenum  131  surrounded by the food container support  13  and disposed above the food containers  12 , and a cooling plenum  31  defined by a duct plate  22  and walls of the food containers  12 . 
     The cover  14  rotates about a pair of hinges  114  in the cover support  27  to open or close the barrier plenum  131 . When the cover  14  is closed, the barrier plenum  131  is insulated from ambient air outside the cover  14 . Instead of one-piece cover  14 , more than one cover can be provided to selectively limit access to the food containers  12 . Preferably, the cover  14  can be transparent. 
     Referring to FIG. 3, there is shown a partial cross sectional view taken along the line  3 — 3  in FIG.  1 . The food preparation table  10  has a temperature controller  37  in the food storage compartment  15 , which controls the operation of the compressor  52  and the pair of fans  33  to maintain a certain temperature set by a user. In addition, the preparation table  10  further includes three supporting rods  28 , both ends of which are slidably rested on the ledge  213 . The food container support  13  is insulated from the counter top  17  by an insulating material  30 , e.g., urethane. 
     Referring to FIG. 4, there is shown a perspective exploded view of parts constituting the cooling system of the food preparation table  10 . The air distributing member  40  has a louver plate  23  with a plurality of intake openings  123  and distributing openings  223 , a fan plate  36  attached to the back of the louver plate  23  and provided with a pair of fan openings  45 , a top louver plate  32  disposed above the louver plate  23 , and three dividing plates  39  affixed on the surface of the top louver plate  32  and dividing equally the air room  41  into four portions. The top louver plate  32  has a plurality of air room openings  132  formed at locations where a flow velocity of the circulating air in the air room  41  is very low. In this embodiment, the air room openings  132  are formed at corners of each portion divided by the dividing plates  39  far from the fans  33 . The food container support  13  has two rows of stagnant air openings  113  on a longer side functioning as a side wall of the air room  41 . The duct plate  22  has a plurality of duct openings  122  formed in a front wall  222 . 
     The operation of the cooling system of the preferred embodiment will now be described with reference to FIGS. 5 and 6. 
     When a temperature sensor (not shown) detects an increase in the temperature of the foodstuffs  43  in the food containers  12 , the temperature controller  37  starts to operate the compressor  52  and the motors  34 . The circulating air around the evaporator  35  loses heat and flows to the fans  33 . The fans  33  force the cooled circulating air to flow into an air distributing plenum  50  through the fan openings  45 . Large portion of the circulating air in the air distributing plenum  50  flows into the cooling plenum  31  through the distributing openings  223 . Small portion of the circulating air in the air distributing plenum  50  is pushed into the air room  41  through the air room openings  132  and then into the barrier plenum  131  through the stagnant air openings  113 . 
     As shown in FIG. 4, the distributing openings  223  formed far from the fans  33  are large while the openings  223  formed near to the fans  33  are small, and there is no opening in front of the fans  33 . Accordingly, the large portion of the circulating air flowing out of the air distributing plenum  50  is distributed evenly along the width of the food preparation table  10 . The large portion of the circulating air travels around the food containers  12  absorbing heat from the food containers  12  and foodstuffs  43  so that the temperature of the foodstuffs  43  in the food containers  12  can be decreased. 
     The small portion of the circulating air flowing out of the air room  41  through the stagnant air openings  113  has a very low velocity slightly greater than zero (0) and thus accumulated above the foodstuffs  43  in the food containers as shown in FIG.  6 . The accumulated air  44  absorbs heat from the foodstuffs and forms an insulating barrier, which prevents the foodstuffs  43  from absorbing heat from an outer air having relatively high temperature. 
     Further, the food container support  13  is in contact with the air room  41 , so its temperature can be lower than that of the accumulated air and absorbs heat from the accumulated air in the barrier plenum  131 . 
     The large portion of the circulating air in the cooling plenum  31  flows into the food storage compartment  15  through the duct openings  122  and then to the evaporator  35  through the intake openings  123 . 
     In the food preparation table  10  employing the inventive cooling system described above, since the accumulated air  44  forms the insulating barrier, the food preparation table  10  can prevent the outer air from being absorbed into the food storage compartment  15 . 
     Further, since there is no need to provide the circulating air while the temperature of the accumulated air is maintained at a relatively low level compared with the ambient air, the fans  33  may operate intermittently, thereby making the food preparation table more efficient than conventional ones. 
     While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes and modification may be made without departing from the spirit and scope of the invention as defined in the following.