Patent Publication Number: US-6701735-B1

Title: Multi deck merchandiser with horizontal air curtains

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a refrigerated display case. 
     Refrigerated display cases found in supermarkets and convenience stores may have an open viewing area that permits consumers to reach into the display case without opening a door to retrieve refrigerated product from the display cases shelves. To keep the product refrigerated within the display case, these refrigerated merchandisers have an air curtain that extends from near the top to near the bottom of the display case over the viewing area. An outlet at the top of the display case blows air vertically down to a warm air return near the bottom of the display case. This air is drawn into the warm air return by a fan that then blows the warmed air over a refrigeration coil and recycles the air back to the air outlet at the top of the display case through a duct extending from the refrigeration coil to the air outlet. 
     Due to the relative locations of the air inlet and air outlet, the air curtain generally extends over the entire viewing area. The air curtain is consequently very large. Because of the size of the air curtain, it is more susceptible to the intrusion of ambient warm air from outside the display case. It thus takes a significant amount of energy to cool product within the display case. While display cases exist that direct air over the product from the back to the front of the display case (horizontally), air from these outlets continues to be returned to an air inlet at the bottom of the display case resulting in a longer than necessary air curtain. 
     A need therefore exists for an energy efficient display merchandiser that offers the benefits of an open viewing area without excessive energy consumption. 
     SUMMARY OF THE INVENTION 
     The inventive refrigeration system directs an air curtain over products on a shelf from an air outlet located near the back of the display case to an air inlet located at the front of the shelf rather than near the bottom of the display case. In this way, the display case limits the size of the air curtain to about the length of the shelf. By shortening the size of the air curtain, less energy is consumed resulting in more efficient refrigeration. Also, a horizontal air curtain is more effective as gravity will tend to hold the air curtain on the product in the display case. 
     Like other refrigerator display cases, the inventive display case has a display space. A cooling element, such as a refrigeration coil, cools air for the display case. This air is directed across the cooling element to an air outlet that guides the air directly into the display space. However, unlike existing display cases, the inventive display case has a shelf with an air inlet that serves to draw air from the air outlet so that air travels just about the length of the shelf instead over the entire viewing area. 
     The inventive system may have several shelves, each with their own air inlet. An air mover, such as a blower, may direct air to the multiple air outlets on one end of each shelf, which in turn direct air to an associated air inlet located on the other end of the shelf. The air outlet may guide the air across the length of each shelf and be place above the anticipated height of product on the shelves. Air from each air inlet may then be returned through the shelf to a cooling element and then recycled back to the air outlet. 
     The shelves may be wider on one end than the other. Moreover, one end of the shelves may be at a higher elevation than the other. The shelves may be placed at various elevations, including the bottom of the display case. 
     The shelves may have a duct to communicate air from the air inlet back to the cooling element. The shelves may themselves act like a duct. An additional duct may serve to channel air from the air inlet directly to the refrigeration coil. Also, each of the shelves may have their own coil and fan so that air may circulate around each shelf. 
     The invention limits the size of the air curtain and improves product refrigeration without significantly increasing costs. Moreover, the path of the air serves to expel warm air from the display space. Without significant expense, the inventive display case provides an energy efficient merchandiser to refrigerate product. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows: 
     FIG. 1 illustrates a side view of the inventive refrigeration system, showing display case, air outlet, and air inlet. 
     FIG. 2 illustrates a perspective view of the inventive refrigeration system. 
     FIG. 3 illustrates a variation of the inventive refrigeration system. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG. 1, inventive refrigeration system  10  comprises display case  14  having front area  18 , back area  22  defined by back wall  101 , top area  26  and bottom area  30 . Each of these areas helps to define display space  34  contained within display case  14 . As shown, display case  14  has viewing area  35 , an open area that permits consumers to reach into display case  14  to retrieve product  74  stored on shelves  50 . FIG. 2 shows a perspective view of display case  14 . These features of display case  14  are well known. 
     In contrast to existing display cases, refrigeration system  10  has air curtains  11 ,  12 ,  13  that extend generally horizontally (from back of display case to front) from air outlets  46  located on back wall  101  to air inlets  62  on shelves  50 . As shown in FIGS. 1 and 2, rather than extend across viewing area  35 , air curtains  11 ,  12 ,  13  may extend only over products  74  on shelves  50 . The size and orientation of each of these individual air curtains  11 ,  12  and  13  is less than viewing area  35 , resulting in less ambient air infiltration from outside display case  14 . As detailed below, the size of each air curtain  11 ,  12 , and  13  is limited by the novel location of air inlets  62  on shelves  50 . 
     Air curtains  11 ,  12  and  13  are created by air mover  42 , such as a blower, like a fan panel, or other air moving devices, that blows air out of air outlets  46  to air inlets  62 . Air outlets  46  may direct air downward toward shelves  50  or simply to front area  18  from back area  22 . Air inlets  62  on shelves  50  serve to draw air expelled from air outlets  46  via air mover  42 , which uses air inlets  62  as a source for air for air outlets  46 . Rather than place air inlets  62  at the bottom of display case as known, inventive refrigeration system  10  places air inlets  62  on shelves  50 , thereby limiting the size of air curtains  11 ,  12  and  13  to the distance between air outlet  46  on one side of the shelf and air inlet  62  on the other. Thus, air travels from air outlet  46  from back area  22  of display case  14  to air inlet  62  on shelves  50  near front area  18  instead of to an air inlet located at the bottom of the display case. Moreover, air outlets  46  may be placed at a predetermined height above the expected height of product  70  so that air flows over product rather than through product  74 . 
     As further shown in FIG. 1, shelves  50  have first portion  54  having width W 1  and second portion  58  having width W 2 . Width W 1  is less than width W 2 , resulting in angled shelves that permit air curtain  11 ,  12  and  13  to flow down product  74  from air outlet  46  to air inlet  62 . Air inlet  62  is at height H 1 , which is at a lower height than air outlet  46 , which is at height H 2 . This design takes advantage of the fact that cool air tends downward. 
     Once air has passed from air outlet  46  to air inlet  62 , air then passes underneath shelves  50  through ducts  52  that may extend through shelves  50  to vertical return ducts  70 . This air is then cycled back to cooling element  38 , such as a refrigeration coil, via air mover  42 , which draws the warmed air over cooling element  38  and then returns cooled air to air outlets  46  through supply duct  68 . A worker in this art would understand that the FIG. 1 is a somewhat schematic view, and the blower, passages, parts, etc. may have a different arrangement. 
     As shown in FIG. 2, product  74  is insulated from ambient warm air by air curtains  11 ,  12  and  13  that extend from air outlets  46  to air inlets  62  on shelves  50 . Air outlets  46  may direct air downward from back area  22  to front area  34  away from top area  26 . In this way, each air curtain is smaller resulting in an energy efficient refrigeration system design. The positioning of air curtains in a more horizontal rather than vertical fashion further permits air curtains  11 ,  12  and  13  to take advantage of forces on the air curtain, such as buoyancy forces, that tend to pull the cold air curtain down. Moreover, the Coanda-effect, a viscous effect, acts to keep air curtains II,  12  and  13  on a continuous surface as provided by shelves  50 . As a consequence of this horizontal orientation of air curtains  11 ,  12  and  13  cold air is kept on the product. 
     FIG. 3 illustrates a variation of the inventive refrigeration system. Within shelf  50  are air mover  80 , a fan, and cooling element  84 , a refrigeration coil. Air mover  80  receives air through air inlet  62  and directs the air to cooling element  84 , which cools the received air. The air is then cycled back over product  74  on shelf  50  through air outlet  46 . Multiple shelves may be used, each with their own air mover  80  and cooling element  84 . 
     The aforementioned description is exemplary rather that limiting. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed. However, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. Hence, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For this reason the following claims should be studied to determine the true scope and content of this invention.