Patent Publication Number: US-9901189-B2

Title: Air duct for refrigeration case

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of prior-filed, U.S. Provisional Application Ser. No. 61/873,612, filed Sep. 4, 2013, the entire contents of which is incorporated by reference herein. 
    
    
     BACKGROUND 
     The present invention relates to refrigeration cases and, more particularly, to an air flow system for a refrigeration display case. 
     Refrigeration cases circulate air through a refrigeration coil to keep the displayed product cool. Air is typically moved through the case in a circular pattern with warm air entering an evaporator for cooling and cold air exiting the evaporator. Product disposed near the cold air outlet is often cooled to a greater extent than product that is positioned near the warm air inlet to the evaporator. 
     SUMMARY 
     In one embodiment, a refrigeration case includes a housing having a top wall and a rear wall and defining an interior chamber having an upper portion and a lower portion, a door pivotably coupled to the housing opposite the rear wall and operable to selectively open and close the interior chamber, a first shelf positioned proximate the lower portion of the interior chamber, a second shelf positioned above the first shelf, a duct wall, a fan, and a diverter. The duct wall is positioned proximate the rear wall and extends between the upper portion of the interior chamber and the lower portion of the interior chamber. The duct wall at least partially defines a flow channel extending between at least the first shelf and the second shelf. The duct wall includes a first opening above the first shelf and a second opening above the second shelf. The fan provides cool air flow and is in fluid communication with the flow channel. The diverter is positioned in the flow channel proximate the second shelf and directs air flow through the second opening and over the second shelf. 
     In another aspect, a refrigeration case includes a housing including a top wall and a rear wall and defining an interior chamber, a door pivotably coupled to the housing opposite the rear wall and operable to selectively open and close the interior chamber, a fan for providing cool air flow, a shelf positioned within the interior chamber proximate the top wall, a flow channel, and a return duct. The shelf includes a front end proximate the door and a rear end positioned away from the door. The flow channel has an inlet in fluid communication with the fan and circulates air flow within the interior chamber. The return duct is positioned above the shelf and includes a first portion and a second portion. The first portion includes a first return opening in fluid communication with the fan and positioned proximate front end of the shelf. The second portion includes a second opening in fluid communication with the fan and positioned proximate the rear end of the shelf. 
     In yet another aspect, a refrigeration case includes a housing including a top wall and a rear wall and defining an interior chamber, a door pivotably coupled to the housing opposite the rear wall and operable to selectively open and close the interior chamber, a first shelf, a second shelf, a third shelf, a fan for providing cool air flow and positioned proximate the top wall, a duct wall, a diverter, and a return duct. The first shelf is positioned proximate the lower portion of the interior chamber. The second shelf is positioned above the first shelf. The third shelf is positioned above the second shelf. The duct wall is positioned proximate the rear wall and at least partially defines a flow channel extending between at least the first shelf and the second shelf. The duct wall includes a first opening proximate the first shelf and a second opening proximate the second shelf. The diverter is positioned in the flow channel proximate the second shelf, and the diverter directs air flow through the second opening and over the second shelf. The return duct is positioned above the third shelf and includes a first return opening and a second return opening. The first return opening is in fluid communication with the fan and is positioned proximate a front end of the shelf. The second opening is in fluid communication with the fan and is positioned proximate the rear end of the shelf. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a refrigeration case. 
         FIG. 2  is a right side view of the refrigeration case of  FIG. 1  with a right wall removed. 
         FIG. 3  is an enlarged right side view of a portion of the case of  FIG. 2 . 
         FIG. 4  is a perspective view of the portion of the case of  FIG. 3 . 
         FIG. 5  is a perspective view of a fan housing. 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” and “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. 
     DETAILED DESCRIPTION 
       FIG. 1  shows a refrigeration case  10  including a rear wall  14 , a pair of doors  18  opposite the rear wall  14 , a pair of side walls  22 , a top  26 , and a bottom  30 , and these components define an interior chamber. The doors  18  swing open to provide access to the contents of the interior chamber of the case  10 . In other embodiments, the case  10  may include fewer or more doors  18  or may include sliding doors. 
     As shown in  FIGS. 2-4 , the case  10  further includes a fan  34  ( FIG. 3 ), an evaporator coil  38 , an air duct wall  42 , and multiple shelves  44  positioned in a stacked configuration between the air duct wall  42  and the front door  18 . The air duct wall  42  extends from an upper portion of the case  10  toward the bottom  30  ( FIG. 2 ) of the case  10 , parallel to the rear wall  14 . A space between the air duct wall  42  and the rear wall  14  defines an air flow channel. In the illustrated embodiment, the fan  34  is positioned adjacent a return duct  46  ( FIG. 3 ) proximate a top shelf  44   a  of the case  10 . The coil  38  is positioned in an upper portion of the case  10 , between the fan  34  and an inlet  50  of the air flow channel. 
     As shown in  FIG. 4 , multiple openings  54  are spaced apart along the length and width of the air duct wall  42  to allow air to flow from the air flow channel, through the air duct wall  42  and over product (not shown) supported on the shelves  44 . In one embodiment, the air duct wall  42  includes a set of openings  54  positioned between each shelf  44  (e.g., a first set of openings positioned above the shelf  44   b  but below the shelf  44   a , a second set of openings positioned between the shelf  44   b  and the shelf  44   c , etc.). 
     In addition, a flow diverter or parabolic diffuser or wedge  58  is positioned in the air flow channel. The wedge  58  has a slanted surface  62  forming an acute angle with respect to the air duct wall  42 . The slanted surface  62  faces the air inlet  50  in order to reduce the pressure drop of the air flowing over the wedge  58 . In the illustrated embodiment, the wedge  58  is coupled to the rear wall  14  and is positioned opposite a portion of the air duct wall  42  proximate an upper shelf  44   b . The angled surface  62  is positioned above the shelf  44   b , thereby constricting flow in the air flow channel past the shelf  44   b . As a result, cool air flow is directed through the openings  54  and over the shelf  44   b . In one embodiment, the wedge  58  is made of a foam material, such as expandable polystyrene (EPS). 
     Referring to  FIGS. 3 and 4 , the return duct  46  includes a first portion or ceiling  66  and a second portion or wall  70 . The ceiling  66  provides a false ceiling adjacent the inside of the top  26  and forming a flow channel between the top  26  and the ceiling  66 . The ceiling  66  also includes openings forming a grill  74  positioned proximate the front of the case  10 . The wall  70  is positioned behind the grill  74  (i.e., proximate the rear of the shelf  44   a , behind the product supported by the top shelf  44   a ), and includes multiple openings  78  ( FIG. 4 ). In the illustrated embodiment, the wall  70  is substantially vertical and the grill  74  is slanted such that the grill  74  is oriented at an acute angle with respect to the top  26  of the case  10 .  FIG. 5  shows the return duct  46  in further detail. 
     Referring now to  FIG. 3 , the fan  34  draws air through the grill  74  and openings  78  of the return duct  46 . The fan  34  pushes the air over the coil  38  and into the air flow channel. The air is cooled as it passes over the coil  38 . As the air passes through the air flow channel, the air is directed through the openings  54  ( FIG. 4 ) of the air duct wall  42  and over the shelves  44   b  and  44   c  to cool any products supported on the shelves  44   b  and  44   c . In particular, the wedge  58  “squeezes” the air in a portion of the air flow channel and acts like a weir, thereby reducing or metering a portion of the air in the area in front of the wedge  58 . This metering action diverts a portion of the air flow through the openings  54  and onto an upper shelf  44   b . Thus, a larger portion of cool air flows over the upper shelf  44   b  than if the wedge  58  was not present. The remaining air flows around the wedge  58  and passes over the lower shelves  44   c.    
     After the cool air flows over the shelves  44   b  and  44   c , the warmed air is drawn by the suction of the fan  34  to the return duct  46 . A portion of the air passes through the grill  74  and into the channel formed between the ceiling  66  and the top  26 . Another portion of the air flows over the product on the top shelf  44   a  and through the openings  78  ( FIG. 4 ) in the wall  70  of the return duct  46 . 
     The openings  78  in the wall  70  increase the flow of cool air over the warmest products in the case  10  (i.e., the product on the top shelf  44   a ). The increased air flow cools the products in the case  10  more efficiently and reduces temperature variations between the products on the lower shelves  44   c  and the products on the top shelf  44   a . In addition, the openings  78  permit a greater volume of air to be discharged through the fan  34  near the top  26  of the case  10 , eliminating the dead space beneath the ceiling  66 . In one embodiment, the increased air flow over the top shelf  44   a  and the increased air flow over the upper shelf  44   b  through the air duct wall  42  results in a temperature reduction of the product on those shelves  44   a  and  44   b  by approximately 1-2 degrees Fahrenheit. 
     Thus, the invention provides, among other things, an air duct for a refrigeration case. Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described.