Patent Publication Number: US-6655169-B2

Title: Refrigerator airflow distribution assembly

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to refrigerators, and more specifically, to an apparatus for reducing temperature gradients in refrigerator fresh food compartments. 
     Known refrigerators typically regulate a temperature of a fresh food compartment by opening and closing a damper established in flow communication with a freezer compartment, and by operating a fan to draw cold freezer compartment air into the fresh food compartment as needed to maintain a desired temperature in the fresh food compartment. 
     In known refrigerators, however, achieving uniform temperatures in the fresh food compartment is challenging. For a variety of reasons, items placed in upper regions of the fresh food compartment tend to be undercooled, and items placed in lower regions of the fresh food compartment tend to be overcooled. While efforts have been made to control and improve airflow distribution in refrigerator fresh food compartments, see, for example U.S. Pat. No. 6,055,820, lower cost and simpler airflow distribution systems are desired. 
     BRIEF SUMMARY OF THE INVENTION 
     In an exemplary embodiment, an airflow distribution assembly for a refrigerator includes an airflow diverter coupled to a cover and in flow communication with freezer compartment air. The diverter includes a primary flow path and at least one diverter opening therethrough, and the cover and diverter form a secondary flow path in flow communication with the first flow path through the diverter opening. Freezer compartment air is directed to the primary flow path, and a portion of the air in the primary flow path flows through the diverter opening and into the secondary flow path. From the secondary flow path, the cold air is introduced to the fresh food compartment through one or more vents in the cover. 
     More specifically, the diverter includes a plurality of openings between the primary flow path and the secondary flow path of different sizes to obtain desired flow rates into the secondary flow path to achieve balanced airflow into the fresh food compartment through the cover vents, thereby reducing temperature gradients in the fresh food compartment. The secondary flow path includes a longitudinal portion extending substantially vertically in the fresh food compartment, and a plurality of laterally extending portions located adjacent the vents. The cover vents are located adjacent the lateral portions of the secondary flow path, and the cover is rounded to uniformly direct cold air from the secondary flow path into the fresh food compartment. A sealing gasket extends between the diverter and the cover to prevent mixing of cold freezer compartment air with warmer fresh food compartment air except through the cover vents. 
     A lower end of the airflow distribution assembly includes a discharge extending from the cover to supply cold freezer compartment air to a fresh food compartment storage drawer to regulate temperature in the storage drawer, for example, for meat and/or vegetable storage therein. 
     A versatile airflow distribution assembly is therefore provided that improves airflow in a refrigerator fresh food compartment and reduces undesirable temperature gradients in the fresh food compartment, as well as supplying cold air to a storage drawer for regulating temperature therein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a refrigerator including an airflow distribution assembly. 
     FIG. 2 is a partial perspective cut away view of a portion of the refrigerator shown in Figure; 
     FIG. 3 is a front elevational view of a portion of the refrigerator shown in FIG. 1; 
     FIG. 4 is a sectional view of the portion of the refrigerator shown in FIG. 4; 
     FIG. 5 is a perspective view of the airflow distribution assembly shown in FIGS. 1-4; and 
     FIG. 6 is a cross-sectional view of a portion of another embodiment of a refrigerator. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates an exemplary side-by-side refrigerator  100  in which the invention may be practiced. It is contemplated, however, that the teaching of the description set forth below is applicable to other types of refrigeration appliances, including but not limited to top and bottom mount refrigerators wherein undesirable temperature gradients exist. The present invention is therefore not intended to be limited to be limited to any particular type or configuration of a refrigerator, such as refrigerator  100 . 
     Refrigerator  100  includes a fresh food storage compartment  102  and freezer storage compartment  104 , an outer case  106  and inner liners  108  and  110 . A space between case  106  and liners  108  and  110 , and between liners  108  and  110 , is filled with foamed-in-place insulation. Outer case  106  normally is formed by folding a sheet of a suitable material, such as pre-painted steel, into an inverted U-shape to form top and side walls of case. A bottom wall of case  106  normally is formed separately and attached to the case side walls and to a bottom frame that provides support for refrigerator  100 . Inner liners  108  and  110  are molded from a suitable plastic material to form freezer compartment  104  and fresh food compartment  106 , respectively. Alternatively, liners  108 ,  110  may be formed by bending and welding a sheet of a suitable metal, such as steel. The illustrative embodiment includes two separate liners  108 ,  110  as it is a relatively large capacity unit and separate liners add strength and are easier to maintain within manufacturing tolerances. In smaller refrigerators, a single liner is formed and a mullion spans between opposite sides of the liner to divide it into a freezer compartment and a fresh food compartment. 
     A breaker strip  112  extends between a case front flange and outer front edges of liners. Breaker strip  112  is formed from a suitable resilient material, such as an extruded acrylo-butadiene-syrene based material (commonly referred to as ABS). 
     The insulation in the space between liners  108 ,  110  is covered by another strip of suitable resilient material, which also commonly is referred to as a mullion  114 . Mullion  114  also preferably is formed of an extruded ABS material. It will be understood that in a refrigerator with separate mullion dividing an unitary liner into a freezer and a fresh food compartment, a front face member of mullion corresponds to mullion  114 . Breaker strip  112  and mullion  114  form a front face, and extend completely around inner peripheral edges of case  106  and vertically between liners  108 ,  110 . Mullion  114 , insulation between compartments, and a spaced wall of liners separating compartments, sometimes are collectively referred to herein as a center mullion wall  116 . 
     Shelves  118  and slide-out drawers  120 ,  121  normally are provided in fresh food compartment  102  to support items being stored therein. A bottom drawer or pan  122  partly forms a quick chill and thaw system (not shown in FIG. 1) selectively controlled, together with other refrigerator features, by a microprocessor (not shown) according to user preference via manipulation of a control interface  124  mounted in an upper region of fresh food storage compartment  102  and coupled to the microprocessor. Shelves  126  and wire baskets  128  are also provided in freezer compartment  104 . In addition, an ice maker  130  may be provided in freezer compartment  104 . 
     A freezer door  132  and a fresh food door  134  close access openings to fresh food and freezer compartments  102 ,  104 , respectively. Each door  132 ,  134  is mounted by a top hinge  136  and a bottom hinge (not shown) to rotate about its outer vertical edge between an open position, as shown in FIG. 1, and a closed position (not shown) closing the associated storage compartment. Freezer door  132  includes a plurality of storage shelves  138  and a sealing gasket  140 , and fresh food door  134  also includes a plurality of storage shelves  142  and a sealing gasket  144 . 
     For improved airflow and reduced temperature gradients within fresh food compartment  102 , an airflow distribution assembly  150  extends along a rear wall of fresh food compartment  102 . As explained below, airflow distribution assembly provides metered distribution of cold air from freezer compartment  104 . In addition, airflow distribution supplies cold air to slide-out drawer  120  for temperature regulation of meat and/or vegetables stored therein. 
     FIG. 2 is a partial cutaway view of fresh food compartment  102  illustrating storage drawers  120 ,  121  stacked upon one another and positioned above a quick chill and thaw system  160 . Quick chill and thaw system  160  includes an air handler  162  and pan  122  located adjacent a pentagonal-shaped machinery compartment  164  (shown in phantom in FIG. 2) to minimize fresh food compartment space utilized by quick chill and thaw system  160 . Storage drawers  120  includes a rear wall  152  having a cutout portion therein for receiving regulated airflow from airflow distribution assembly  150  (shown in FIG.  1 ). Slide-out drawer  121  is a conventional slide-out drawer without internal temperature control, and a temperature of storage drawer  121  is therefore substantially equal to an operating temperature of fresh food compartment  102 . In an alternative embodiment, drawer  121  also receives cold air from airflow distribution assembly  150 . 
     Quick chill and thaw pan  122  is positioned slightly forward of storage drawers  120  to accommodate machinery compartment  164 , and an air handler  162  selectively controls a temperature of air in pan  122  and circulates air within pan  122  to increase heat transfer to and from pan contents for timely thawing and rapid chilling, respectively. When quick thaw and chill system  160  is inactivated, pan  122  reaches a steady state at a temperature equal to the temperature of fresh food compartment  102 , and pan  122  functions as a third storage drawer. In alternative embodiments, greater or fewer numbers of storage drawers  120 ,  121  and quick chill and thaw systems  160 , and other relative sizes of quick chill pans  122  and storage drawers  120 ,  121  are employed. Further, it is recognized that the benefits of the present invention are achieved independently of quick chill and thaw system  160  and quick chill and thaw pan  122 , and the invention is therefore not limited in any manner whatsoever to refrigerators including a quick chill and thaw system  160 . 
     In accordance with known refrigerators, machinery compartment  164  at least partially contains components for executing a vapor compression cycle for cooling, air. The components include a compressor (not shown), a condenser (not shown), an expansion device (not shown), and an evaporator (not shown) connected in series and charged with a refrigerant. The evaporator is a type of heat exchanger which transfers heat from air passing over the evaporator to a refrigerant flowing, through the evaporator, thereby causing, the refrigerant to vaporize. 
     The vapor cycle components are controlled by a microprocessor and deliver cooled air to freezer compartment  104  (shown in FIG.  1 ). Temperature regulation of fresh food compartment  102  (shown in FIG. 1) is obtained by opening, or closing, a damper in flow communication with an opening through center mullion wall  116  (shown in FIG. 1) and drawing air into fresh food compartment  102  with a fan (not shown). Airflow distribution assembly  150  (shown in FIG. 1) provides even distribution of freezer compartment air throughout fresh food compartment  102  and into slide out drawer  120  for meat and vegetable temperature regulation. 
     FIG. 3 is a front elevational view of fresh food compartment  102  and including air distribution assembly  150  attached to a rear wall of liner  108 . Air distribution assembly  150  is in flow communication with freezer compartment  104  (shown in FIG. 1) through a duct  170  and a damper (not shown) in flow communication with an opening through center mullion wall  116  (shown in FIG.  1 ). Duct  170  is located at the top of fresh food compartment  102 , and a fan (not shown) is used to draw freezer compartment air though the damper and duct  170  and downwardly into fresh food compartment  102  through vents  174  in a cover  176  of air distribution assembly  150 . Cover  176  extends substantially from a top of fresh food compartment  102  to a mid-section of fresh food compartment  102  and is substantially centered between side walls of fresh food liner  108 . A lower end of air distribution assembly includes a discharge  178  having vents for supplying freezer compartment air to storage drawer  120  (shown in FIGS. 1 and 2) and regulate temperature therein. 
     In alternative embodiments, other relative positions of duct  170  and air distribution assembly  150  are employed with respect to one another and with respect to fresh food compartment  102 . For example, in one alternative embodiment, air distribution assembly  150  is attached to a side wall of fresh food liner  108 . In a further alternative embodiment, duct  170  is located elsewhere than at the top of fresh food compartment  102  and air distribution assembly is used to direct air upwardly and/or downwardly from duct  170  to fresh food compartment  102 . In still another alternative embodiment, air distribution assembly  150  is off-centered on one of the vertical walls of liner  108   
     FIG. 4 is a sectional view of fresh food compartment  102  illustrating air distribution assembly extending along a top and rear wall of liner  108 . Air a n distribution assembly includes a hood portion  180  extending along the top of fresh food compartment  102 , discharge  178  positioned for engagement with cutout portion of storage drawer  120  (see FIG.  2 ), and a vent portion  182  extending between hood portion  180  and discharge  178 . In one embodiment, a manually adjustable knob  184  is located proximally to discharge  178  for user adjustment of airflow through discharge  178  into storage drawer  120 . In an alternative embodiment, electronic controls are employed to select, deselect, and adjust airflow into storage drawer  120 . 
     Air distribution assembly  150 , as illustrated in FIG. 4, is compact in size to minimize impact on useable space in fresh food compartment  102 , while providing regulated airflow into lower portions of fresh food compartment  102  to reduce temperature gradients therein. Vents  174  (shown in FIG. 3) are strategically positioned at selected vertical elevations to optimize airflow conditions in fresh food compartment  102  over a range of shelf positions  186  with respect to liner  108 . 
     In a further embodiment, air distribution assembly  150  also directs regulated air downwardly below discharge  178  so that air is directed behind storage drawers  120  and  121  (shown in FIG. 2) and ultimately between storage drawers  120  and  122  toward a front of fresh food compartment  102 . As such, cold air is directed into and around lower bins  142  of fresh food compartment door  134 . 
     FIG. 5 is a perspective view of vent portion  182  of airflow distribution assembly  150  (shown in FIGS. 1,  3  and  4 ). Vent portion  182  includes cover  176  including an inlet end  190  and an outlet end  192 , and a diverter  196  including an inlet end  198  and an outlet end  200  corresponding to ends  190 ,  192  of cover  176 . Diverter  196  is coupled to cover  176 , and a gasket  202  extends between diverter  196  and cover  196  to form an airtight seal between cover  176  and diverter  196 . Diverter  196  is slightly recessed in rounded cover  176 , and when vent portion  182  is attached to fresh food compartment liner  108  (shown in FIGS.  1 - 4 ), gaskets  202  seal vent portion  150  from fresh food compartment  102  and prevent mixing of fresh food compartment air with freezer compartment air inside of vent portion  182 . When attached to liner  108 , diverter  196  extends between liner  108  and cover  176 . Inlet ends  190 ,  198  are placed in flow communication with hood portion  180  (shown in FIG. 4) and outlet ends  192 ,  200  are placed in flow communication with discharge  178  (shown in FIGS.  3  and  4 ). 
     Diverter  196  is closed at inlet end  198  so that freezer compartment air is forced into a primary flow path between diverter  196  and liner  108 . A secondary flow path is created between diverter  196  and cover  106 . Secondary flow path includes a longitudinal portion  204  extending parallel to a longitudinal axis  206  of vent portion  182 , and a plurality of lateral portions  208  extending generally transverse to longitudinal portion  204 . In an exemplary embodiment, diverter  196  is fabricated from expanded polystyrene (EPS), and secondary flow path is integrally formed into diverter  196 . In alternative embodiments, diverter  196  is fabricated from other known materials and in further embodiments is of a multi-piece construction. 
     The secondary flow path of diverter  196  is enclosed by cover  176 . Cover vents  174  (shown in FIGS. 1 and 3) are positioned adjacent lateral portions  208  of secondary path so that freezer compartment air is distributed radially from curved cover  176  at a full width of lateral portions  208  of the secondary flow path. In an exemplary embodiment, cover is fabricated from a known plastic material and contains a separately fabricated diverter  196 . It is contemplated, however, that in alternative embodiments, cover  176  and diverter  196  may be fabricated from the same material, and may even be integrally formed in, for example, a known molding operation. 
     Diverter includes a plurality of diverter openings  210  positioned between inlet end  198  and outlet end  200  and establishing flow communication between the primary flow path and the secondary flow path. A size of openings  210  decreases from inlet end  198  to outlet end  200 , and each opening  210  is positioned within longitudinal portion  204  of the secondary flow path, i.e., away from lateral portions  208  of the secondary flow path. Therefore, as freezer compartment air travels from inlet end  198  to outlet end  200 , a portion of the air in the primary airflow path is diverted through each successive diverter opening  210  and into longitudinal portions  204  of the secondary flow path. Once in the secondary flow path, air flows downwardly to lateral portions  208  of the secondary flow path and a portion of the air in lateral portions  208  flows through vents  174  in cover  176  and into fresh food compartment  102 . 
     As diverter openings are larger near inlet end  198 , more air is diverted from the primary flow path in upper regions of vent portion  182  than in lower regions of vent portion  182 , thereby metering air distribution to select locations in a manner to balance temperature gradients in fresh food compartment  102 . With properly dimensioned diverter openings  210 , secondary flow path portions, and cover vents  174  located at strategic vertical locations in fresh food compartment  102 , a substantially uniform temperature gradient in fresh food compartment  102  is realized. It is appreciated that appropriate dimensions will vary for particular refrigerator capacities, platforms and configurations. 
     Cover outlet end  192  extends beyond diverter outlet end  200  so that the primary and secondary flow paths converge as air is moved toward storage drawer discharge  178  (shown in FIGS.  3  and  4 ). 
     FIG. 6 is a sectional view of another embodiment of a refrigerator  220  wherein common elements with refrigerator  100  (as described in FIGS. 1-5 are illustrated with like reference characters. Air distribution assembly extends along a top and rear wall of liner  108  in fresh food compartment  102 , and includes a hood portion  180  extending along the top of fresh food compartment  102 , a discharge  178  positioned between storage drawers  120  and  121  (also shown in FIG.  2 ), and a vent portion  182  extending between hood portion  180  and discharge  178 . In one embodiment, a manually adjustable knob  184  is located proximally to discharge  178  for user adjustment of airflow through discharge  178  into storage drawer  120 . In an alternative embodiment, electronic controls are employed to select, deselect, and adjust airflow into storage drawer  120 . 
     Air distribution assembly  150 , as illustrated in FIG. 6, is compact in size to minimize impact on useable space in fresh food compartment  102 , while providing regulated airflow into lower portions of fresh food compartment  102  to reduce temperature gradients therein. Vents  174  (shown in FIG. 3) are strategically positioned at selected vertical elevations to optimize airflow conditions in fresh food compartment  102  over a range of shelf positions  186  with respect to liner  108 . By positioning air distribution assembly discharge  178  between storage drawers  120  and  121 , airflow is facilitated between storage drawers  120  and  121  toward a front of fresh food compartment  102  (as illustrated by the arrow in FIG. 6) and into lower bins  142  (shown in FIG. 1) of fresh food compartment door  134  (shown in FIG.  1 ). Thus, unlike refrigerator  100  (shown in FIGS. 1-5) in which air distribution assembly  150  delivers regulated airflow into storage drawer  120  (shown in FIGS.  1  and  2 ), air distribution assembly  150  in refrigerator  220  delivers regulated airflow around storage pans  120 ,  121  to the front of lower fresh food compartment  102 . 
     In a further embodiment, additional air distribution assembly discharges  178  may be positioned between, for example, drawers  121  and  122  to further reduce temperature gradients in a lower portion of fresh food compartment  102 . 
     A cost effective airflow distribution assembly is therefore provided that achieves desirable air temperature balance in a refrigerator fresh food compartment with minimal impact on usable fresh food compartment space and while providing freezer compartment air for temperature regulation of a fresh food drawer. 
     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.