Abstract:
A refrigerator includes a refrigerating compartment configured to preserve food, the compartment including a plurality of walls forming a cavity, a door coupled to the compartment configured to cover the cavity when in a closed position, and a passageway positioned on at least one of the walls and the door such that air within the cavity is in flow communication with air outside the cavity when the door is in the closed position.

Description:
BACKGROUND OF INVENTION 
   This invention relates generally to refrigerators, and more specifically, to controlling humidity in a refrigerator fresh food compartment. 
   At least some known refrigerators regulate the temperature of the 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. The temperature of the evaporator surface in the freezer compartment is typically much lower than the air temperature in the fresh food compartment. This drives moisture from the fresh food compartment to the freezer compartment where it mostly freezes on the evaporator surface. This reduces the relative humidity in the fresh food compartment. Relative air humidity in the fresh food compartment of the refrigerator has a high influence on the fresh food quality. Deterioration of some foods such as vegetables, fruits, mushrooms, bread, and the like in a low humidity environment is rapid and irreversible. 
   As is well known with humidors, freshness of items that are stored at room temperatures is readily accomplished merely by sealing a storage container to prevent the entry of air. This is not effective, however, in a refrigerated environment where temperatures are maintained well below a normal room temperature of, for instance, 70 degrees. In known refrigerators, maintaining fresh food quality is a challenge. While covered crisper pans and meat storage pans are typically provided in the fresh food compartment to retard the drying out of items placed therein, there is no provision for controlling the relative humidity of the remainder of the fresh food compartment of the refrigerator. 
   SUMMARY OF INVENTION 
   In one aspect, a refrigerator includes a refrigerating compartment configured to preserve food, the compartment including a plurality of walls forming a cavity, a door coupled to the compartment configured to cover the cavity when in a closed position, and a passageway positioned on at least one of the walls and the door such that air within the cavity is in flow communication with air outside the cavity when the door is in the closed position. 
   In another aspect, a refrigerator includes a refrigerating compartment configured to preserve food, the compartment including a plurality of walls forming a cavity, a door coupled to the compartment configured to cover the cavity when in a closed position, and a gasket positioned between the compartment and the door when the door is in the closed position, and a passageway positioned in the gasket such that air within the cavity is in flow communication with air outside the cavity when the door is in the closed position. 
   In another aspect, a refrigerator includes a refrigerating compartment configured to preserve food, the compartment including a plurality of walls forming a cavity, a door coupled to the compartment configured to cover the cavity when in a closed position, and a user interface operationally coupled to the cavity, the interface configured to receive a relative humidity setting, and maintain the relative humidity within the cavity about the received relative humidity setting by controlling an exchange of outside air with the cavity. 
   In another aspect, a method for manufacturing a refrigerator includes forming a refrigerating compartment configured to preserve food, the compartment including a plurality of walls forming a cavity, coupling a door to the compartment such that the door covers the cavity when in a closed position, and coupling a passageway to at least one of the cavity and the door such that air within the cavity is in flow communication with air outside the cavity when the door is in the closed position. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a perspective view of a refrigerator. 
       FIG. 2  is a partial perspective view of an exterior surface of the refrigerator of FIG.  1 . 
       FIG. 3  is a cross sectional view of a refrigerator sidewall including a passageway. 
       FIG. 4  is a cross sectional view of a refrigerator sidewall including another embodiment of a passageway. 
       FIG. 5  is front perspective view of a refrigerator with a control interface. 
       FIG. 6  is a cross sectional view of a refrigerator side wall with an automatically controlled vent. 
   

   DETAILED DESCRIPTION 
     FIG. 1  illustrates an exemplary side-by-side refrigerator  100 . It is contemplated, however, that the teaching of the description set forth herein is applicable to other types of refrigeration appliances, including but not limited to top and bottom mount refrigerators where humidity control in the fresh food compartment is desirable. The present invention is therefore not intended 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  106 . 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 . 
     FIG. 2  is a partial view of door  134  and the exterior sidewall  250  and top  260  of fresh food compartment  102  of refrigerator  100 . Rear panel  270  is opposite door  134 . Shown in sidewall  250  is a sizing member  210  which is partially obstructing a passageway  204  which is shown in more detail in  FIGS. 3 and 4 . Passageway  204  extends from inner panel  108  to outer case  106  in sidewall  250  and connects fresh food compartment  102  to outside air through a plurality of openings  220  which may be positioned on outer case  106  of sidewall  250  as shown in  FIG. 2  or on inner liner  108  as shown in FIG.  3 . In one embodiment, a filtering member  230  is positioned within passageway  204 . In another embodiment, filtering member  230  is adjacent passageway  204 . In another embodiment, a plurality of louvers  240  are positioned at one end of passageway  204 . Sizing member  210  is positioned on either the refrigerator exterior as shown in  FIGS. 2 and 3  or the interior as depicted in FIG.  4 . 
   Humidity control in fresh food compartment  102  is achieved by the controlled communication of outside air with fresh food compartment  102  through passageway  204 . Sizing member  210  is movable to allow adjustment of air flow through passageway  204 . In one embodiment, sizing member  210  is user adjustable. In another embodiment, sizing member  210  is automatically moved. Filtering member  230  facilitates keeping foreign particles from entering fresh food compartment  102  through passageway  204 . In another embodiment, louvers  240  facilitate keeping foreign particles from entering fresh food compartment  102 . Though shown on the sidewall  250  of refrigerator  100 , in  FIG. 2 , in an alternative embodiment, passageway  204  is located on the refrigerator top  260  or rear panel  270  or in refrigerator door  134 . Passageway  204  can be of any shape and can extend linearly as shown in  FIGS. 3 and 4  or could extend at least partially arcuately between inner liner  108  and case  106 . In another embodiment, passageway  204  is positioned on sealing gasket  144 . 
     FIG. 5  illustrates a control interface  324  of refrigerator  100 . Interface  324  includes a humidity sensor  340  that senses the relative humidity of the air inside fresh food compartment  102 , and a display panel  330  that numerically displays the sensed value. In addition to humidity control, other control features associated with the refrigerator may be incorporated into control interface  324 . 
   Control interface  324  provides for automatic operation of the humidity control system. In  FIG. 6 , automatic vent  400  is shown within a side wall of refrigerator between inner liner  108  and outer case  106 . Vent  400  includes a damper  410  positioned in passageway  204  and an actuator such as servomotor  420 . Damper  410  is pivoted at pivot end  412  and is movable to open and close vent  400  by opening and closing air passageways  430  in the outer case. Damper  410  is connected to servomotor  420  by an actuating rod  414 . Servomotor  420 , controlled by the refrigerator control system, opens and closes the vent passage  400  based on the humidity level detected by sensor  340  and a humidity level selected by the user through an adjustment dial  350 . For example, control interface  324  receives a relative humidity setting from a user and controls actuator  420  to maintain the humidity level in fresh food compartment  102  about the selected humidity level. In one embodiment, the relative humidity is maintained within 2% of the received setting. That is, for a selected setting of 70%, the relative humidity within fresh food compartment  102  is maintained within the range of 68% to 72%. In another embodiment, the relative humidity is maintained within 4% of the selected level. Alternatively, in another embodiment, control interface  324  maintains the relative humidity within 8% of the selected level. 
   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.